xref: /linux/drivers/scsi/sg.c (revision 757dea93e136b219af09d3cd56a81063fdbdef1a)
1 /*
2  *  History:
3  *  Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
4  *           to allow user process control of SCSI devices.
5  *  Development Sponsored by Killy Corp. NY NY
6  *
7  * Original driver (sg.c):
8  *        Copyright (C) 1992 Lawrence Foard
9  * Version 2 and 3 extensions to driver:
10  *        Copyright (C) 1998 - 2005 Douglas Gilbert
11  *
12  *  Modified  19-JAN-1998  Richard Gooch <rgooch@atnf.csiro.au>  Devfs support
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2, or (at your option)
17  * any later version.
18  *
19  */
20 
21 static int sg_version_num = 30534;	/* 2 digits for each component */
22 #define SG_VERSION_STR "3.5.34"
23 
24 /*
25  *  D. P. Gilbert (dgilbert@interlog.com, dougg@triode.net.au), notes:
26  *      - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
27  *        the kernel/module needs to be built with CONFIG_SCSI_LOGGING
28  *        (otherwise the macros compile to empty statements).
29  *
30  */
31 #include <linux/module.h>
32 
33 #include <linux/fs.h>
34 #include <linux/kernel.h>
35 #include <linux/sched.h>
36 #include <linux/string.h>
37 #include <linux/mm.h>
38 #include <linux/errno.h>
39 #include <linux/mtio.h>
40 #include <linux/ioctl.h>
41 #include <linux/fcntl.h>
42 #include <linux/init.h>
43 #include <linux/poll.h>
44 #include <linux/smp_lock.h>
45 #include <linux/moduleparam.h>
46 #include <linux/cdev.h>
47 #include <linux/seq_file.h>
48 #include <linux/blkdev.h>
49 #include <linux/delay.h>
50 #include <linux/scatterlist.h>
51 
52 #include "scsi.h"
53 #include <scsi/scsi_dbg.h>
54 #include <scsi/scsi_host.h>
55 #include <scsi/scsi_driver.h>
56 #include <scsi/scsi_ioctl.h>
57 #include <scsi/sg.h>
58 
59 #include "scsi_logging.h"
60 
61 #ifdef CONFIG_SCSI_PROC_FS
62 #include <linux/proc_fs.h>
63 static char *sg_version_date = "20061027";
64 
65 static int sg_proc_init(void);
66 static void sg_proc_cleanup(void);
67 #endif
68 
69 #define SG_ALLOW_DIO_DEF 0
70 #define SG_ALLOW_DIO_CODE /* compile out by commenting this define */
71 
72 #define SG_MAX_DEVS 32768
73 
74 /*
75  * Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
76  * Then when using 32 bit integers x * m may overflow during the calculation.
77  * Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m
78  * calculates the same, but prevents the overflow when both m and d
79  * are "small" numbers (like HZ and USER_HZ).
80  * Of course an overflow is inavoidable if the result of muldiv doesn't fit
81  * in 32 bits.
82  */
83 #define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))
84 
85 #define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
86 
87 int sg_big_buff = SG_DEF_RESERVED_SIZE;
88 /* N.B. This variable is readable and writeable via
89    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
90    of this size (or less if there is not enough memory) will be reserved
91    for use by this file descriptor. [Deprecated usage: this variable is also
92    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
93    the kernel (i.e. it is not a module).] */
94 static int def_reserved_size = -1;	/* picks up init parameter */
95 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
96 
97 static int scatter_elem_sz = SG_SCATTER_SZ;
98 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
99 
100 #define SG_SECTOR_SZ 512
101 #define SG_SECTOR_MSK (SG_SECTOR_SZ - 1)
102 
103 #define SG_DEV_ARR_LUMP 32	/* amount to over allocate sg_dev_arr by */
104 
105 static int sg_add(struct class_device *, struct class_interface *);
106 static void sg_remove(struct class_device *, struct class_interface *);
107 
108 static DEFINE_RWLOCK(sg_dev_arr_lock);	/* Also used to lock
109 							   file descriptor list for device */
110 
111 static struct class_interface sg_interface = {
112 	.add		= sg_add,
113 	.remove		= sg_remove,
114 };
115 
116 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
117 	unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
118 	unsigned short sglist_len; /* size of malloc'd scatter-gather list ++ */
119 	unsigned bufflen;	/* Size of (aggregate) data buffer */
120 	unsigned b_malloc_len;	/* actual len malloc'ed in buffer */
121 	struct scatterlist *buffer;/* scatter list */
122 	char dio_in_use;	/* 0->indirect IO (or mmap), 1->dio */
123 	unsigned char cmd_opcode; /* first byte of command */
124 } Sg_scatter_hold;
125 
126 struct sg_device;		/* forward declarations */
127 struct sg_fd;
128 
129 typedef struct sg_request {	/* SG_MAX_QUEUE requests outstanding per file */
130 	struct sg_request *nextrp;	/* NULL -> tail request (slist) */
131 	struct sg_fd *parentfp;	/* NULL -> not in use */
132 	Sg_scatter_hold data;	/* hold buffer, perhaps scatter list */
133 	sg_io_hdr_t header;	/* scsi command+info, see <scsi/sg.h> */
134 	unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
135 	char res_used;		/* 1 -> using reserve buffer, 0 -> not ... */
136 	char orphan;		/* 1 -> drop on sight, 0 -> normal */
137 	char sg_io_owned;	/* 1 -> packet belongs to SG_IO */
138 	volatile char done;	/* 0->before bh, 1->before read, 2->read */
139 } Sg_request;
140 
141 typedef struct sg_fd {		/* holds the state of a file descriptor */
142 	struct sg_fd *nextfp;	/* NULL when last opened fd on this device */
143 	struct sg_device *parentdp;	/* owning device */
144 	wait_queue_head_t read_wait;	/* queue read until command done */
145 	rwlock_t rq_list_lock;	/* protect access to list in req_arr */
146 	int timeout;		/* defaults to SG_DEFAULT_TIMEOUT      */
147 	int timeout_user;	/* defaults to SG_DEFAULT_TIMEOUT_USER */
148 	Sg_scatter_hold reserve;	/* buffer held for this file descriptor */
149 	unsigned save_scat_len;	/* original length of trunc. scat. element */
150 	Sg_request *headrp;	/* head of request slist, NULL->empty */
151 	struct fasync_struct *async_qp;	/* used by asynchronous notification */
152 	Sg_request req_arr[SG_MAX_QUEUE];	/* used as singly-linked list */
153 	char low_dma;		/* as in parent but possibly overridden to 1 */
154 	char force_packid;	/* 1 -> pack_id input to read(), 0 -> ignored */
155 	volatile char closed;	/* 1 -> fd closed but request(s) outstanding */
156 	char cmd_q;		/* 1 -> allow command queuing, 0 -> don't */
157 	char next_cmd_len;	/* 0 -> automatic (def), >0 -> use on next write() */
158 	char keep_orphan;	/* 0 -> drop orphan (def), 1 -> keep for read() */
159 	char mmap_called;	/* 0 -> mmap() never called on this fd */
160 } Sg_fd;
161 
162 typedef struct sg_device { /* holds the state of each scsi generic device */
163 	struct scsi_device *device;
164 	wait_queue_head_t o_excl_wait;	/* queue open() when O_EXCL in use */
165 	int sg_tablesize;	/* adapter's max scatter-gather table size */
166 	Sg_fd *headfp;		/* first open fd belonging to this device */
167 	volatile char detached;	/* 0->attached, 1->detached pending removal */
168 	volatile char exclude;	/* opened for exclusive access */
169 	char sgdebug;		/* 0->off, 1->sense, 9->dump dev, 10-> all devs */
170 	struct gendisk *disk;
171 	struct cdev * cdev;	/* char_dev [sysfs: /sys/cdev/major/sg<n>] */
172 } Sg_device;
173 
174 static int sg_fasync(int fd, struct file *filp, int mode);
175 /* tasklet or soft irq callback */
176 static void sg_cmd_done(void *data, char *sense, int result, int resid);
177 static int sg_start_req(Sg_request * srp);
178 static void sg_finish_rem_req(Sg_request * srp);
179 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
180 static int sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp,
181 			 int tablesize);
182 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
183 			   Sg_request * srp);
184 static ssize_t sg_new_write(Sg_fd * sfp, const char __user *buf, size_t count,
185 			    int blocking, int read_only, Sg_request ** o_srp);
186 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
187 			   unsigned char *cmnd, int timeout, int blocking);
188 static int sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind,
189 		      int wr_xf, int *countp, unsigned char __user **up);
190 static int sg_write_xfer(Sg_request * srp);
191 static int sg_read_xfer(Sg_request * srp);
192 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
193 static void sg_remove_scat(Sg_scatter_hold * schp);
194 static void sg_build_reserve(Sg_fd * sfp, int req_size);
195 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
196 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
197 static struct page *sg_page_malloc(int rqSz, int lowDma, int *retSzp);
198 static void sg_page_free(struct page *page, int size);
199 static Sg_fd *sg_add_sfp(Sg_device * sdp, int dev);
200 static int sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
201 static void __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
202 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
203 static Sg_request *sg_add_request(Sg_fd * sfp);
204 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
205 static int sg_res_in_use(Sg_fd * sfp);
206 static int sg_allow_access(unsigned char opcode, char dev_type);
207 static int sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len);
208 static Sg_device *sg_get_dev(int dev);
209 #ifdef CONFIG_SCSI_PROC_FS
210 static int sg_last_dev(void);
211 #endif
212 
213 static Sg_device **sg_dev_arr = NULL;
214 static int sg_dev_max;
215 static int sg_nr_dev;
216 
217 #define SZ_SG_HEADER sizeof(struct sg_header)
218 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
219 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
220 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
221 
222 static int
223 sg_open(struct inode *inode, struct file *filp)
224 {
225 	int dev = iminor(inode);
226 	int flags = filp->f_flags;
227 	struct request_queue *q;
228 	Sg_device *sdp;
229 	Sg_fd *sfp;
230 	int res;
231 	int retval;
232 
233 	nonseekable_open(inode, filp);
234 	SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
235 	sdp = sg_get_dev(dev);
236 	if ((!sdp) || (!sdp->device))
237 		return -ENXIO;
238 	if (sdp->detached)
239 		return -ENODEV;
240 
241 	/* This driver's module count bumped by fops_get in <linux/fs.h> */
242 	/* Prevent the device driver from vanishing while we sleep */
243 	retval = scsi_device_get(sdp->device);
244 	if (retval)
245 		return retval;
246 
247 	if (!((flags & O_NONBLOCK) ||
248 	      scsi_block_when_processing_errors(sdp->device))) {
249 		retval = -ENXIO;
250 		/* we are in error recovery for this device */
251 		goto error_out;
252 	}
253 
254 	if (flags & O_EXCL) {
255 		if (O_RDONLY == (flags & O_ACCMODE)) {
256 			retval = -EPERM; /* Can't lock it with read only access */
257 			goto error_out;
258 		}
259 		if (sdp->headfp && (flags & O_NONBLOCK)) {
260 			retval = -EBUSY;
261 			goto error_out;
262 		}
263 		res = 0;
264 		__wait_event_interruptible(sdp->o_excl_wait,
265 			((sdp->headfp || sdp->exclude) ? 0 : (sdp->exclude = 1)), res);
266 		if (res) {
267 			retval = res;	/* -ERESTARTSYS because signal hit process */
268 			goto error_out;
269 		}
270 	} else if (sdp->exclude) {	/* some other fd has an exclusive lock on dev */
271 		if (flags & O_NONBLOCK) {
272 			retval = -EBUSY;
273 			goto error_out;
274 		}
275 		res = 0;
276 		__wait_event_interruptible(sdp->o_excl_wait, (!sdp->exclude),
277 					   res);
278 		if (res) {
279 			retval = res;	/* -ERESTARTSYS because signal hit process */
280 			goto error_out;
281 		}
282 	}
283 	if (sdp->detached) {
284 		retval = -ENODEV;
285 		goto error_out;
286 	}
287 	if (!sdp->headfp) {	/* no existing opens on this device */
288 		sdp->sgdebug = 0;
289 		q = sdp->device->request_queue;
290 		sdp->sg_tablesize = min(q->max_hw_segments,
291 					q->max_phys_segments);
292 	}
293 	if ((sfp = sg_add_sfp(sdp, dev)))
294 		filp->private_data = sfp;
295 	else {
296 		if (flags & O_EXCL)
297 			sdp->exclude = 0;	/* undo if error */
298 		retval = -ENOMEM;
299 		goto error_out;
300 	}
301 	return 0;
302 
303       error_out:
304 	scsi_device_put(sdp->device);
305 	return retval;
306 }
307 
308 /* Following function was formerly called 'sg_close' */
309 static int
310 sg_release(struct inode *inode, struct file *filp)
311 {
312 	Sg_device *sdp;
313 	Sg_fd *sfp;
314 
315 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
316 		return -ENXIO;
317 	SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
318 	sg_fasync(-1, filp, 0);	/* remove filp from async notification list */
319 	if (0 == sg_remove_sfp(sdp, sfp)) {	/* Returns 1 when sdp gone */
320 		if (!sdp->detached) {
321 			scsi_device_put(sdp->device);
322 		}
323 		sdp->exclude = 0;
324 		wake_up_interruptible(&sdp->o_excl_wait);
325 	}
326 	return 0;
327 }
328 
329 static ssize_t
330 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
331 {
332 	Sg_device *sdp;
333 	Sg_fd *sfp;
334 	Sg_request *srp;
335 	int req_pack_id = -1;
336 	sg_io_hdr_t *hp;
337 	struct sg_header *old_hdr = NULL;
338 	int retval = 0;
339 
340 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
341 		return -ENXIO;
342 	SCSI_LOG_TIMEOUT(3, printk("sg_read: %s, count=%d\n",
343 				   sdp->disk->disk_name, (int) count));
344 
345 	if (!access_ok(VERIFY_WRITE, buf, count))
346 		return -EFAULT;
347 	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
348 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
349 		if (!old_hdr)
350 			return -ENOMEM;
351 		if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
352 			retval = -EFAULT;
353 			goto free_old_hdr;
354 		}
355 		if (old_hdr->reply_len < 0) {
356 			if (count >= SZ_SG_IO_HDR) {
357 				sg_io_hdr_t *new_hdr;
358 				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
359 				if (!new_hdr) {
360 					retval = -ENOMEM;
361 					goto free_old_hdr;
362 				}
363 				retval =__copy_from_user
364 				    (new_hdr, buf, SZ_SG_IO_HDR);
365 				req_pack_id = new_hdr->pack_id;
366 				kfree(new_hdr);
367 				if (retval) {
368 					retval = -EFAULT;
369 					goto free_old_hdr;
370 				}
371 			}
372 		} else
373 			req_pack_id = old_hdr->pack_id;
374 	}
375 	srp = sg_get_rq_mark(sfp, req_pack_id);
376 	if (!srp) {		/* now wait on packet to arrive */
377 		if (sdp->detached) {
378 			retval = -ENODEV;
379 			goto free_old_hdr;
380 		}
381 		if (filp->f_flags & O_NONBLOCK) {
382 			retval = -EAGAIN;
383 			goto free_old_hdr;
384 		}
385 		while (1) {
386 			retval = 0; /* following macro beats race condition */
387 			__wait_event_interruptible(sfp->read_wait,
388 				(sdp->detached ||
389 				(srp = sg_get_rq_mark(sfp, req_pack_id))),
390 				retval);
391 			if (sdp->detached) {
392 				retval = -ENODEV;
393 				goto free_old_hdr;
394 			}
395 			if (0 == retval)
396 				break;
397 
398 			/* -ERESTARTSYS as signal hit process */
399 			goto free_old_hdr;
400 		}
401 	}
402 	if (srp->header.interface_id != '\0') {
403 		retval = sg_new_read(sfp, buf, count, srp);
404 		goto free_old_hdr;
405 	}
406 
407 	hp = &srp->header;
408 	if (old_hdr == NULL) {
409 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
410 		if (! old_hdr) {
411 			retval = -ENOMEM;
412 			goto free_old_hdr;
413 		}
414 	}
415 	memset(old_hdr, 0, SZ_SG_HEADER);
416 	old_hdr->reply_len = (int) hp->timeout;
417 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
418 	old_hdr->pack_id = hp->pack_id;
419 	old_hdr->twelve_byte =
420 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
421 	old_hdr->target_status = hp->masked_status;
422 	old_hdr->host_status = hp->host_status;
423 	old_hdr->driver_status = hp->driver_status;
424 	if ((CHECK_CONDITION & hp->masked_status) ||
425 	    (DRIVER_SENSE & hp->driver_status))
426 		memcpy(old_hdr->sense_buffer, srp->sense_b,
427 		       sizeof (old_hdr->sense_buffer));
428 	switch (hp->host_status) {
429 	/* This setup of 'result' is for backward compatibility and is best
430 	   ignored by the user who should use target, host + driver status */
431 	case DID_OK:
432 	case DID_PASSTHROUGH:
433 	case DID_SOFT_ERROR:
434 		old_hdr->result = 0;
435 		break;
436 	case DID_NO_CONNECT:
437 	case DID_BUS_BUSY:
438 	case DID_TIME_OUT:
439 		old_hdr->result = EBUSY;
440 		break;
441 	case DID_BAD_TARGET:
442 	case DID_ABORT:
443 	case DID_PARITY:
444 	case DID_RESET:
445 	case DID_BAD_INTR:
446 		old_hdr->result = EIO;
447 		break;
448 	case DID_ERROR:
449 		old_hdr->result = (srp->sense_b[0] == 0 &&
450 				  hp->masked_status == GOOD) ? 0 : EIO;
451 		break;
452 	default:
453 		old_hdr->result = EIO;
454 		break;
455 	}
456 
457 	/* Now copy the result back to the user buffer.  */
458 	if (count >= SZ_SG_HEADER) {
459 		if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
460 			retval = -EFAULT;
461 			goto free_old_hdr;
462 		}
463 		buf += SZ_SG_HEADER;
464 		if (count > old_hdr->reply_len)
465 			count = old_hdr->reply_len;
466 		if (count > SZ_SG_HEADER) {
467 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
468 				retval = -EFAULT;
469 				goto free_old_hdr;
470 			}
471 		}
472 	} else
473 		count = (old_hdr->result == 0) ? 0 : -EIO;
474 	sg_finish_rem_req(srp);
475 	retval = count;
476 free_old_hdr:
477 	kfree(old_hdr);
478 	return retval;
479 }
480 
481 static ssize_t
482 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
483 {
484 	sg_io_hdr_t *hp = &srp->header;
485 	int err = 0;
486 	int len;
487 
488 	if (count < SZ_SG_IO_HDR) {
489 		err = -EINVAL;
490 		goto err_out;
491 	}
492 	hp->sb_len_wr = 0;
493 	if ((hp->mx_sb_len > 0) && hp->sbp) {
494 		if ((CHECK_CONDITION & hp->masked_status) ||
495 		    (DRIVER_SENSE & hp->driver_status)) {
496 			int sb_len = SCSI_SENSE_BUFFERSIZE;
497 			sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
498 			len = 8 + (int) srp->sense_b[7];	/* Additional sense length field */
499 			len = (len > sb_len) ? sb_len : len;
500 			if (copy_to_user(hp->sbp, srp->sense_b, len)) {
501 				err = -EFAULT;
502 				goto err_out;
503 			}
504 			hp->sb_len_wr = len;
505 		}
506 	}
507 	if (hp->masked_status || hp->host_status || hp->driver_status)
508 		hp->info |= SG_INFO_CHECK;
509 	if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
510 		err = -EFAULT;
511 		goto err_out;
512 	}
513 	err = sg_read_xfer(srp);
514       err_out:
515 	sg_finish_rem_req(srp);
516 	return (0 == err) ? count : err;
517 }
518 
519 static ssize_t
520 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
521 {
522 	int mxsize, cmd_size, k;
523 	int input_size, blocking;
524 	unsigned char opcode;
525 	Sg_device *sdp;
526 	Sg_fd *sfp;
527 	Sg_request *srp;
528 	struct sg_header old_hdr;
529 	sg_io_hdr_t *hp;
530 	unsigned char cmnd[MAX_COMMAND_SIZE];
531 
532 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
533 		return -ENXIO;
534 	SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n",
535 				   sdp->disk->disk_name, (int) count));
536 	if (sdp->detached)
537 		return -ENODEV;
538 	if (!((filp->f_flags & O_NONBLOCK) ||
539 	      scsi_block_when_processing_errors(sdp->device)))
540 		return -ENXIO;
541 
542 	if (!access_ok(VERIFY_READ, buf, count))
543 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
544 	if (count < SZ_SG_HEADER)
545 		return -EIO;
546 	if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
547 		return -EFAULT;
548 	blocking = !(filp->f_flags & O_NONBLOCK);
549 	if (old_hdr.reply_len < 0)
550 		return sg_new_write(sfp, buf, count, blocking, 0, NULL);
551 	if (count < (SZ_SG_HEADER + 6))
552 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
553 
554 	if (!(srp = sg_add_request(sfp))) {
555 		SCSI_LOG_TIMEOUT(1, printk("sg_write: queue full\n"));
556 		return -EDOM;
557 	}
558 	buf += SZ_SG_HEADER;
559 	__get_user(opcode, buf);
560 	if (sfp->next_cmd_len > 0) {
561 		if (sfp->next_cmd_len > MAX_COMMAND_SIZE) {
562 			SCSI_LOG_TIMEOUT(1, printk("sg_write: command length too long\n"));
563 			sfp->next_cmd_len = 0;
564 			sg_remove_request(sfp, srp);
565 			return -EIO;
566 		}
567 		cmd_size = sfp->next_cmd_len;
568 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
569 	} else {
570 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
571 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
572 			cmd_size = 12;
573 	}
574 	SCSI_LOG_TIMEOUT(4, printk(
575 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
576 /* Determine buffer size.  */
577 	input_size = count - cmd_size;
578 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
579 	mxsize -= SZ_SG_HEADER;
580 	input_size -= SZ_SG_HEADER;
581 	if (input_size < 0) {
582 		sg_remove_request(sfp, srp);
583 		return -EIO;	/* User did not pass enough bytes for this command. */
584 	}
585 	hp = &srp->header;
586 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
587 	hp->cmd_len = (unsigned char) cmd_size;
588 	hp->iovec_count = 0;
589 	hp->mx_sb_len = 0;
590 	if (input_size > 0)
591 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
592 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
593 	else
594 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
595 	hp->dxfer_len = mxsize;
596 	hp->dxferp = (char __user *)buf + cmd_size;
597 	hp->sbp = NULL;
598 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
599 	hp->flags = input_size;	/* structure abuse ... */
600 	hp->pack_id = old_hdr.pack_id;
601 	hp->usr_ptr = NULL;
602 	if (__copy_from_user(cmnd, buf, cmd_size))
603 		return -EFAULT;
604 	/*
605 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
606 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
607 	 * is a non-zero input_size, so emit a warning.
608 	 */
609 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV)
610 		if (printk_ratelimit())
611 			printk(KERN_WARNING
612 			       "sg_write: data in/out %d/%d bytes for SCSI command 0x%x--"
613 			       "guessing data in;\n" KERN_WARNING "   "
614 			       "program %s not setting count and/or reply_len properly\n",
615 			       old_hdr.reply_len - (int)SZ_SG_HEADER,
616 			       input_size, (unsigned int) cmnd[0],
617 			       current->comm);
618 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
619 	return (k < 0) ? k : count;
620 }
621 
622 static ssize_t
623 sg_new_write(Sg_fd * sfp, const char __user *buf, size_t count,
624 	     int blocking, int read_only, Sg_request ** o_srp)
625 {
626 	int k;
627 	Sg_request *srp;
628 	sg_io_hdr_t *hp;
629 	unsigned char cmnd[MAX_COMMAND_SIZE];
630 	int timeout;
631 	unsigned long ul_timeout;
632 
633 	if (count < SZ_SG_IO_HDR)
634 		return -EINVAL;
635 	if (!access_ok(VERIFY_READ, buf, count))
636 		return -EFAULT; /* protects following copy_from_user()s + get_user()s */
637 
638 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
639 	if (!(srp = sg_add_request(sfp))) {
640 		SCSI_LOG_TIMEOUT(1, printk("sg_new_write: queue full\n"));
641 		return -EDOM;
642 	}
643 	hp = &srp->header;
644 	if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
645 		sg_remove_request(sfp, srp);
646 		return -EFAULT;
647 	}
648 	if (hp->interface_id != 'S') {
649 		sg_remove_request(sfp, srp);
650 		return -ENOSYS;
651 	}
652 	if (hp->flags & SG_FLAG_MMAP_IO) {
653 		if (hp->dxfer_len > sfp->reserve.bufflen) {
654 			sg_remove_request(sfp, srp);
655 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
656 		}
657 		if (hp->flags & SG_FLAG_DIRECT_IO) {
658 			sg_remove_request(sfp, srp);
659 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
660 		}
661 		if (sg_res_in_use(sfp)) {
662 			sg_remove_request(sfp, srp);
663 			return -EBUSY;	/* reserve buffer already being used */
664 		}
665 	}
666 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
667 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
668 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
669 		sg_remove_request(sfp, srp);
670 		return -EMSGSIZE;
671 	}
672 	if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
673 		sg_remove_request(sfp, srp);
674 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
675 	}
676 	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
677 		sg_remove_request(sfp, srp);
678 		return -EFAULT;
679 	}
680 	if (read_only &&
681 	    (!sg_allow_access(cmnd[0], sfp->parentdp->device->type))) {
682 		sg_remove_request(sfp, srp);
683 		return -EPERM;
684 	}
685 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
686 	if (k < 0)
687 		return k;
688 	if (o_srp)
689 		*o_srp = srp;
690 	return count;
691 }
692 
693 static int
694 sg_common_write(Sg_fd * sfp, Sg_request * srp,
695 		unsigned char *cmnd, int timeout, int blocking)
696 {
697 	int k, data_dir;
698 	Sg_device *sdp = sfp->parentdp;
699 	sg_io_hdr_t *hp = &srp->header;
700 
701 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
702 	hp->status = 0;
703 	hp->masked_status = 0;
704 	hp->msg_status = 0;
705 	hp->info = 0;
706 	hp->host_status = 0;
707 	hp->driver_status = 0;
708 	hp->resid = 0;
709 	SCSI_LOG_TIMEOUT(4, printk("sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
710 			  (int) cmnd[0], (int) hp->cmd_len));
711 
712 	if ((k = sg_start_req(srp))) {
713 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: start_req err=%d\n", k));
714 		sg_finish_rem_req(srp);
715 		return k;	/* probably out of space --> ENOMEM */
716 	}
717 	if ((k = sg_write_xfer(srp))) {
718 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: write_xfer, bad address\n"));
719 		sg_finish_rem_req(srp);
720 		return k;
721 	}
722 	if (sdp->detached) {
723 		sg_finish_rem_req(srp);
724 		return -ENODEV;
725 	}
726 
727 	switch (hp->dxfer_direction) {
728 	case SG_DXFER_TO_FROM_DEV:
729 	case SG_DXFER_FROM_DEV:
730 		data_dir = DMA_FROM_DEVICE;
731 		break;
732 	case SG_DXFER_TO_DEV:
733 		data_dir = DMA_TO_DEVICE;
734 		break;
735 	case SG_DXFER_UNKNOWN:
736 		data_dir = DMA_BIDIRECTIONAL;
737 		break;
738 	default:
739 		data_dir = DMA_NONE;
740 		break;
741 	}
742 	hp->duration = jiffies_to_msecs(jiffies);
743 /* Now send everything of to mid-level. The next time we hear about this
744    packet is when sg_cmd_done() is called (i.e. a callback). */
745 	if (scsi_execute_async(sdp->device, cmnd, hp->cmd_len, data_dir, srp->data.buffer,
746 				hp->dxfer_len, srp->data.k_use_sg, timeout,
747 				SG_DEFAULT_RETRIES, srp, sg_cmd_done,
748 				GFP_ATOMIC)) {
749 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: scsi_execute_async failed\n"));
750 		/*
751 		 * most likely out of mem, but could also be a bad map
752 		 */
753 		sg_finish_rem_req(srp);
754 		return -ENOMEM;
755 	} else
756 		return 0;
757 }
758 
759 static int
760 sg_srp_done(Sg_request *srp, Sg_fd *sfp)
761 {
762 	unsigned long iflags;
763 	int done;
764 
765 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
766 	done = srp->done;
767 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
768 	return done;
769 }
770 
771 static int
772 sg_ioctl(struct inode *inode, struct file *filp,
773 	 unsigned int cmd_in, unsigned long arg)
774 {
775 	void __user *p = (void __user *)arg;
776 	int __user *ip = p;
777 	int result, val, read_only;
778 	Sg_device *sdp;
779 	Sg_fd *sfp;
780 	Sg_request *srp;
781 	unsigned long iflags;
782 
783 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
784 		return -ENXIO;
785 	SCSI_LOG_TIMEOUT(3, printk("sg_ioctl: %s, cmd=0x%x\n",
786 				   sdp->disk->disk_name, (int) cmd_in));
787 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
788 
789 	switch (cmd_in) {
790 	case SG_IO:
791 		{
792 			int blocking = 1;	/* ignore O_NONBLOCK flag */
793 
794 			if (sdp->detached)
795 				return -ENODEV;
796 			if (!scsi_block_when_processing_errors(sdp->device))
797 				return -ENXIO;
798 			if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
799 				return -EFAULT;
800 			result =
801 			    sg_new_write(sfp, p, SZ_SG_IO_HDR,
802 					 blocking, read_only, &srp);
803 			if (result < 0)
804 				return result;
805 			srp->sg_io_owned = 1;
806 			while (1) {
807 				result = 0;	/* following macro to beat race condition */
808 				__wait_event_interruptible(sfp->read_wait,
809 					(sdp->detached || sfp->closed || sg_srp_done(srp, sfp)),
810 							   result);
811 				if (sdp->detached)
812 					return -ENODEV;
813 				if (sfp->closed)
814 					return 0;	/* request packet dropped already */
815 				if (0 == result)
816 					break;
817 				srp->orphan = 1;
818 				return result;	/* -ERESTARTSYS because signal hit process */
819 			}
820 			write_lock_irqsave(&sfp->rq_list_lock, iflags);
821 			srp->done = 2;
822 			write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
823 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
824 			return (result < 0) ? result : 0;
825 		}
826 	case SG_SET_TIMEOUT:
827 		result = get_user(val, ip);
828 		if (result)
829 			return result;
830 		if (val < 0)
831 			return -EIO;
832 		if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
833 		    val = MULDIV (INT_MAX, USER_HZ, HZ);
834 		sfp->timeout_user = val;
835 		sfp->timeout = MULDIV (val, HZ, USER_HZ);
836 
837 		return 0;
838 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
839 				/* strange ..., for backward compatibility */
840 		return sfp->timeout_user;
841 	case SG_SET_FORCE_LOW_DMA:
842 		result = get_user(val, ip);
843 		if (result)
844 			return result;
845 		if (val) {
846 			sfp->low_dma = 1;
847 			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
848 				val = (int) sfp->reserve.bufflen;
849 				sg_remove_scat(&sfp->reserve);
850 				sg_build_reserve(sfp, val);
851 			}
852 		} else {
853 			if (sdp->detached)
854 				return -ENODEV;
855 			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
856 		}
857 		return 0;
858 	case SG_GET_LOW_DMA:
859 		return put_user((int) sfp->low_dma, ip);
860 	case SG_GET_SCSI_ID:
861 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
862 			return -EFAULT;
863 		else {
864 			sg_scsi_id_t __user *sg_idp = p;
865 
866 			if (sdp->detached)
867 				return -ENODEV;
868 			__put_user((int) sdp->device->host->host_no,
869 				   &sg_idp->host_no);
870 			__put_user((int) sdp->device->channel,
871 				   &sg_idp->channel);
872 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
873 			__put_user((int) sdp->device->lun, &sg_idp->lun);
874 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
875 			__put_user((short) sdp->device->host->cmd_per_lun,
876 				   &sg_idp->h_cmd_per_lun);
877 			__put_user((short) sdp->device->queue_depth,
878 				   &sg_idp->d_queue_depth);
879 			__put_user(0, &sg_idp->unused[0]);
880 			__put_user(0, &sg_idp->unused[1]);
881 			return 0;
882 		}
883 	case SG_SET_FORCE_PACK_ID:
884 		result = get_user(val, ip);
885 		if (result)
886 			return result;
887 		sfp->force_packid = val ? 1 : 0;
888 		return 0;
889 	case SG_GET_PACK_ID:
890 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
891 			return -EFAULT;
892 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
893 		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
894 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
895 				read_unlock_irqrestore(&sfp->rq_list_lock,
896 						       iflags);
897 				__put_user(srp->header.pack_id, ip);
898 				return 0;
899 			}
900 		}
901 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
902 		__put_user(-1, ip);
903 		return 0;
904 	case SG_GET_NUM_WAITING:
905 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
906 		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
907 			if ((1 == srp->done) && (!srp->sg_io_owned))
908 				++val;
909 		}
910 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
911 		return put_user(val, ip);
912 	case SG_GET_SG_TABLESIZE:
913 		return put_user(sdp->sg_tablesize, ip);
914 	case SG_SET_RESERVED_SIZE:
915 		result = get_user(val, ip);
916 		if (result)
917 			return result;
918                 if (val < 0)
919                         return -EINVAL;
920 		val = min_t(int, val,
921 				sdp->device->request_queue->max_sectors * 512);
922 		if (val != sfp->reserve.bufflen) {
923 			if (sg_res_in_use(sfp) || sfp->mmap_called)
924 				return -EBUSY;
925 			sg_remove_scat(&sfp->reserve);
926 			sg_build_reserve(sfp, val);
927 		}
928 		return 0;
929 	case SG_GET_RESERVED_SIZE:
930 		val = min_t(int, sfp->reserve.bufflen,
931 				sdp->device->request_queue->max_sectors * 512);
932 		return put_user(val, ip);
933 	case SG_SET_COMMAND_Q:
934 		result = get_user(val, ip);
935 		if (result)
936 			return result;
937 		sfp->cmd_q = val ? 1 : 0;
938 		return 0;
939 	case SG_GET_COMMAND_Q:
940 		return put_user((int) sfp->cmd_q, ip);
941 	case SG_SET_KEEP_ORPHAN:
942 		result = get_user(val, ip);
943 		if (result)
944 			return result;
945 		sfp->keep_orphan = val;
946 		return 0;
947 	case SG_GET_KEEP_ORPHAN:
948 		return put_user((int) sfp->keep_orphan, ip);
949 	case SG_NEXT_CMD_LEN:
950 		result = get_user(val, ip);
951 		if (result)
952 			return result;
953 		sfp->next_cmd_len = (val > 0) ? val : 0;
954 		return 0;
955 	case SG_GET_VERSION_NUM:
956 		return put_user(sg_version_num, ip);
957 	case SG_GET_ACCESS_COUNT:
958 		/* faked - we don't have a real access count anymore */
959 		val = (sdp->device ? 1 : 0);
960 		return put_user(val, ip);
961 	case SG_GET_REQUEST_TABLE:
962 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
963 			return -EFAULT;
964 		else {
965 			sg_req_info_t *rinfo;
966 			unsigned int ms;
967 
968 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
969 								GFP_KERNEL);
970 			if (!rinfo)
971 				return -ENOMEM;
972 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
973 			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
974 			     ++val, srp = srp ? srp->nextrp : srp) {
975 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
976 				if (srp) {
977 					rinfo[val].req_state = srp->done + 1;
978 					rinfo[val].problem =
979 					    srp->header.masked_status &
980 					    srp->header.host_status &
981 					    srp->header.driver_status;
982 					if (srp->done)
983 						rinfo[val].duration =
984 							srp->header.duration;
985 					else {
986 						ms = jiffies_to_msecs(jiffies);
987 						rinfo[val].duration =
988 						    (ms > srp->header.duration) ?
989 						    (ms - srp->header.duration) : 0;
990 					}
991 					rinfo[val].orphan = srp->orphan;
992 					rinfo[val].sg_io_owned =
993 							srp->sg_io_owned;
994 					rinfo[val].pack_id =
995 							srp->header.pack_id;
996 					rinfo[val].usr_ptr =
997 							srp->header.usr_ptr;
998 				}
999 			}
1000 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1001 			result = __copy_to_user(p, rinfo,
1002 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1003 			result = result ? -EFAULT : 0;
1004 			kfree(rinfo);
1005 			return result;
1006 		}
1007 	case SG_EMULATED_HOST:
1008 		if (sdp->detached)
1009 			return -ENODEV;
1010 		return put_user(sdp->device->host->hostt->emulated, ip);
1011 	case SG_SCSI_RESET:
1012 		if (sdp->detached)
1013 			return -ENODEV;
1014 		if (filp->f_flags & O_NONBLOCK) {
1015 			if (scsi_host_in_recovery(sdp->device->host))
1016 				return -EBUSY;
1017 		} else if (!scsi_block_when_processing_errors(sdp->device))
1018 			return -EBUSY;
1019 		result = get_user(val, ip);
1020 		if (result)
1021 			return result;
1022 		if (SG_SCSI_RESET_NOTHING == val)
1023 			return 0;
1024 		switch (val) {
1025 		case SG_SCSI_RESET_DEVICE:
1026 			val = SCSI_TRY_RESET_DEVICE;
1027 			break;
1028 		case SG_SCSI_RESET_BUS:
1029 			val = SCSI_TRY_RESET_BUS;
1030 			break;
1031 		case SG_SCSI_RESET_HOST:
1032 			val = SCSI_TRY_RESET_HOST;
1033 			break;
1034 		default:
1035 			return -EINVAL;
1036 		}
1037 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1038 			return -EACCES;
1039 		return (scsi_reset_provider(sdp->device, val) ==
1040 			SUCCESS) ? 0 : -EIO;
1041 	case SCSI_IOCTL_SEND_COMMAND:
1042 		if (sdp->detached)
1043 			return -ENODEV;
1044 		if (read_only) {
1045 			unsigned char opcode = WRITE_6;
1046 			Scsi_Ioctl_Command __user *siocp = p;
1047 
1048 			if (copy_from_user(&opcode, siocp->data, 1))
1049 				return -EFAULT;
1050 			if (!sg_allow_access(opcode, sdp->device->type))
1051 				return -EPERM;
1052 		}
1053 		return sg_scsi_ioctl(filp, sdp->device->request_queue, NULL, p);
1054 	case SG_SET_DEBUG:
1055 		result = get_user(val, ip);
1056 		if (result)
1057 			return result;
1058 		sdp->sgdebug = (char) val;
1059 		return 0;
1060 	case SCSI_IOCTL_GET_IDLUN:
1061 	case SCSI_IOCTL_GET_BUS_NUMBER:
1062 	case SCSI_IOCTL_PROBE_HOST:
1063 	case SG_GET_TRANSFORM:
1064 		if (sdp->detached)
1065 			return -ENODEV;
1066 		return scsi_ioctl(sdp->device, cmd_in, p);
1067 	case BLKSECTGET:
1068 		return put_user(sdp->device->request_queue->max_sectors * 512,
1069 				ip);
1070 	default:
1071 		if (read_only)
1072 			return -EPERM;	/* don't know so take safe approach */
1073 		return scsi_ioctl(sdp->device, cmd_in, p);
1074 	}
1075 }
1076 
1077 #ifdef CONFIG_COMPAT
1078 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1079 {
1080 	Sg_device *sdp;
1081 	Sg_fd *sfp;
1082 	struct scsi_device *sdev;
1083 
1084 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1085 		return -ENXIO;
1086 
1087 	sdev = sdp->device;
1088 	if (sdev->host->hostt->compat_ioctl) {
1089 		int ret;
1090 
1091 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1092 
1093 		return ret;
1094 	}
1095 
1096 	return -ENOIOCTLCMD;
1097 }
1098 #endif
1099 
1100 static unsigned int
1101 sg_poll(struct file *filp, poll_table * wait)
1102 {
1103 	unsigned int res = 0;
1104 	Sg_device *sdp;
1105 	Sg_fd *sfp;
1106 	Sg_request *srp;
1107 	int count = 0;
1108 	unsigned long iflags;
1109 
1110 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))
1111 	    || sfp->closed)
1112 		return POLLERR;
1113 	poll_wait(filp, &sfp->read_wait, wait);
1114 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1115 	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1116 		/* if any read waiting, flag it */
1117 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1118 			res = POLLIN | POLLRDNORM;
1119 		++count;
1120 	}
1121 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1122 
1123 	if (sdp->detached)
1124 		res |= POLLHUP;
1125 	else if (!sfp->cmd_q) {
1126 		if (0 == count)
1127 			res |= POLLOUT | POLLWRNORM;
1128 	} else if (count < SG_MAX_QUEUE)
1129 		res |= POLLOUT | POLLWRNORM;
1130 	SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
1131 				   sdp->disk->disk_name, (int) res));
1132 	return res;
1133 }
1134 
1135 static int
1136 sg_fasync(int fd, struct file *filp, int mode)
1137 {
1138 	int retval;
1139 	Sg_device *sdp;
1140 	Sg_fd *sfp;
1141 
1142 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1143 		return -ENXIO;
1144 	SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
1145 				   sdp->disk->disk_name, mode));
1146 
1147 	retval = fasync_helper(fd, filp, mode, &sfp->async_qp);
1148 	return (retval < 0) ? retval : 0;
1149 }
1150 
1151 static struct page *
1152 sg_vma_nopage(struct vm_area_struct *vma, unsigned long addr, int *type)
1153 {
1154 	Sg_fd *sfp;
1155 	struct page *page = NOPAGE_SIGBUS;
1156 	unsigned long offset, len, sa;
1157 	Sg_scatter_hold *rsv_schp;
1158 	struct scatterlist *sg;
1159 	int k;
1160 
1161 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1162 		return page;
1163 	rsv_schp = &sfp->reserve;
1164 	offset = addr - vma->vm_start;
1165 	if (offset >= rsv_schp->bufflen)
1166 		return page;
1167 	SCSI_LOG_TIMEOUT(3, printk("sg_vma_nopage: offset=%lu, scatg=%d\n",
1168 				   offset, rsv_schp->k_use_sg));
1169 	sg = rsv_schp->buffer;
1170 	sa = vma->vm_start;
1171 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
1172 	     ++k, ++sg) {
1173 		len = vma->vm_end - sa;
1174 		len = (len < sg->length) ? len : sg->length;
1175 		if (offset < len) {
1176 			page = virt_to_page(page_address(sg->page) + offset);
1177 			get_page(page);	/* increment page count */
1178 			break;
1179 		}
1180 		sa += len;
1181 		offset -= len;
1182 	}
1183 
1184 	if (type)
1185 		*type = VM_FAULT_MINOR;
1186 	return page;
1187 }
1188 
1189 static struct vm_operations_struct sg_mmap_vm_ops = {
1190 	.nopage = sg_vma_nopage,
1191 };
1192 
1193 static int
1194 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1195 {
1196 	Sg_fd *sfp;
1197 	unsigned long req_sz, len, sa;
1198 	Sg_scatter_hold *rsv_schp;
1199 	int k;
1200 	struct scatterlist *sg;
1201 
1202 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1203 		return -ENXIO;
1204 	req_sz = vma->vm_end - vma->vm_start;
1205 	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
1206 				   (void *) vma->vm_start, (int) req_sz));
1207 	if (vma->vm_pgoff)
1208 		return -EINVAL;	/* want no offset */
1209 	rsv_schp = &sfp->reserve;
1210 	if (req_sz > rsv_schp->bufflen)
1211 		return -ENOMEM;	/* cannot map more than reserved buffer */
1212 
1213 	sa = vma->vm_start;
1214 	sg = rsv_schp->buffer;
1215 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
1216 	     ++k, ++sg) {
1217 		len = vma->vm_end - sa;
1218 		len = (len < sg->length) ? len : sg->length;
1219 		sa += len;
1220 	}
1221 
1222 	sfp->mmap_called = 1;
1223 	vma->vm_flags |= VM_RESERVED;
1224 	vma->vm_private_data = sfp;
1225 	vma->vm_ops = &sg_mmap_vm_ops;
1226 	return 0;
1227 }
1228 
1229 /* This function is a "bottom half" handler that is called by the
1230  * mid level when a command is completed (or has failed). */
1231 static void
1232 sg_cmd_done(void *data, char *sense, int result, int resid)
1233 {
1234 	Sg_request *srp = data;
1235 	Sg_device *sdp = NULL;
1236 	Sg_fd *sfp;
1237 	unsigned long iflags;
1238 	unsigned int ms;
1239 
1240 	if (NULL == srp) {
1241 		printk(KERN_ERR "sg_cmd_done: NULL request\n");
1242 		return;
1243 	}
1244 	sfp = srp->parentfp;
1245 	if (sfp)
1246 		sdp = sfp->parentdp;
1247 	if ((NULL == sdp) || sdp->detached) {
1248 		printk(KERN_INFO "sg_cmd_done: device detached\n");
1249 		return;
1250 	}
1251 
1252 
1253 	SCSI_LOG_TIMEOUT(4, printk("sg_cmd_done: %s, pack_id=%d, res=0x%x\n",
1254 		sdp->disk->disk_name, srp->header.pack_id, result));
1255 	srp->header.resid = resid;
1256 	ms = jiffies_to_msecs(jiffies);
1257 	srp->header.duration = (ms > srp->header.duration) ?
1258 				(ms - srp->header.duration) : 0;
1259 	if (0 != result) {
1260 		struct scsi_sense_hdr sshdr;
1261 
1262 		memcpy(srp->sense_b, sense, sizeof (srp->sense_b));
1263 		srp->header.status = 0xff & result;
1264 		srp->header.masked_status = status_byte(result);
1265 		srp->header.msg_status = msg_byte(result);
1266 		srp->header.host_status = host_byte(result);
1267 		srp->header.driver_status = driver_byte(result);
1268 		if ((sdp->sgdebug > 0) &&
1269 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1270 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1271 			__scsi_print_sense("sg_cmd_done", sense,
1272 					   SCSI_SENSE_BUFFERSIZE);
1273 
1274 		/* Following if statement is a patch supplied by Eric Youngdale */
1275 		if (driver_byte(result) != 0
1276 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1277 		    && !scsi_sense_is_deferred(&sshdr)
1278 		    && sshdr.sense_key == UNIT_ATTENTION
1279 		    && sdp->device->removable) {
1280 			/* Detected possible disc change. Set the bit - this */
1281 			/* may be used if there are filesystems using this device */
1282 			sdp->device->changed = 1;
1283 		}
1284 	}
1285 	/* Rely on write phase to clean out srp status values, so no "else" */
1286 
1287 	if (sfp->closed) {	/* whoops this fd already released, cleanup */
1288 		SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, freeing ...\n"));
1289 		sg_finish_rem_req(srp);
1290 		srp = NULL;
1291 		if (NULL == sfp->headrp) {
1292 			SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, final cleanup\n"));
1293 			if (0 == sg_remove_sfp(sdp, sfp)) {	/* device still present */
1294 				scsi_device_put(sdp->device);
1295 			}
1296 			sfp = NULL;
1297 		}
1298 	} else if (srp && srp->orphan) {
1299 		if (sfp->keep_orphan)
1300 			srp->sg_io_owned = 0;
1301 		else {
1302 			sg_finish_rem_req(srp);
1303 			srp = NULL;
1304 		}
1305 	}
1306 	if (sfp && srp) {
1307 		/* Now wake up any sg_read() that is waiting for this packet. */
1308 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1309 		write_lock_irqsave(&sfp->rq_list_lock, iflags);
1310 		srp->done = 1;
1311 		wake_up_interruptible(&sfp->read_wait);
1312 		write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1313 	}
1314 }
1315 
1316 static struct file_operations sg_fops = {
1317 	.owner = THIS_MODULE,
1318 	.read = sg_read,
1319 	.write = sg_write,
1320 	.poll = sg_poll,
1321 	.ioctl = sg_ioctl,
1322 #ifdef CONFIG_COMPAT
1323 	.compat_ioctl = sg_compat_ioctl,
1324 #endif
1325 	.open = sg_open,
1326 	.mmap = sg_mmap,
1327 	.release = sg_release,
1328 	.fasync = sg_fasync,
1329 };
1330 
1331 static struct class *sg_sysfs_class;
1332 
1333 static int sg_sysfs_valid = 0;
1334 
1335 static int sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1336 {
1337 	struct request_queue *q = scsidp->request_queue;
1338 	Sg_device *sdp;
1339 	unsigned long iflags;
1340 	void *old_sg_dev_arr = NULL;
1341 	int k, error;
1342 
1343 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1344 	if (!sdp) {
1345 		printk(KERN_WARNING "kmalloc Sg_device failure\n");
1346 		return -ENOMEM;
1347 	}
1348 
1349 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
1350 	if (unlikely(sg_nr_dev >= sg_dev_max)) {	/* try to resize */
1351 		Sg_device **tmp_da;
1352 		int tmp_dev_max = sg_nr_dev + SG_DEV_ARR_LUMP;
1353 		write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1354 
1355 		tmp_da = kzalloc(tmp_dev_max * sizeof(Sg_device *), GFP_KERNEL);
1356 		if (unlikely(!tmp_da))
1357 			goto expand_failed;
1358 
1359 		write_lock_irqsave(&sg_dev_arr_lock, iflags);
1360 		memcpy(tmp_da, sg_dev_arr, sg_dev_max * sizeof(Sg_device *));
1361 		old_sg_dev_arr = sg_dev_arr;
1362 		sg_dev_arr = tmp_da;
1363 		sg_dev_max = tmp_dev_max;
1364 	}
1365 
1366 	for (k = 0; k < sg_dev_max; k++)
1367 		if (!sg_dev_arr[k])
1368 			break;
1369 	if (unlikely(k >= SG_MAX_DEVS))
1370 		goto overflow;
1371 
1372 	SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
1373 	sprintf(disk->disk_name, "sg%d", k);
1374 	disk->first_minor = k;
1375 	sdp->disk = disk;
1376 	sdp->device = scsidp;
1377 	init_waitqueue_head(&sdp->o_excl_wait);
1378 	sdp->sg_tablesize = min(q->max_hw_segments, q->max_phys_segments);
1379 
1380 	sg_nr_dev++;
1381 	sg_dev_arr[k] = sdp;
1382 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1383 	error = k;
1384 
1385  out:
1386 	if (error < 0)
1387 		kfree(sdp);
1388 	kfree(old_sg_dev_arr);
1389 	return error;
1390 
1391  expand_failed:
1392 	printk(KERN_WARNING "sg_alloc: device array cannot be resized\n");
1393 	error = -ENOMEM;
1394 	goto out;
1395 
1396  overflow:
1397 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1398 	sdev_printk(KERN_WARNING, scsidp,
1399 		    "Unable to attach sg device type=%d, minor "
1400 		    "number exceeds %d\n", scsidp->type, SG_MAX_DEVS - 1);
1401 	error = -ENODEV;
1402 	goto out;
1403 }
1404 
1405 static int
1406 sg_add(struct class_device *cl_dev, struct class_interface *cl_intf)
1407 {
1408 	struct scsi_device *scsidp = to_scsi_device(cl_dev->dev);
1409 	struct gendisk *disk;
1410 	Sg_device *sdp = NULL;
1411 	struct cdev * cdev = NULL;
1412 	int error, k;
1413 	unsigned long iflags;
1414 
1415 	disk = alloc_disk(1);
1416 	if (!disk) {
1417 		printk(KERN_WARNING "alloc_disk failed\n");
1418 		return -ENOMEM;
1419 	}
1420 	disk->major = SCSI_GENERIC_MAJOR;
1421 
1422 	error = -ENOMEM;
1423 	cdev = cdev_alloc();
1424 	if (!cdev) {
1425 		printk(KERN_WARNING "cdev_alloc failed\n");
1426 		goto out;
1427 	}
1428 	cdev->owner = THIS_MODULE;
1429 	cdev->ops = &sg_fops;
1430 
1431 	error = sg_alloc(disk, scsidp);
1432 	if (error < 0) {
1433 		printk(KERN_WARNING "sg_alloc failed\n");
1434 		goto out;
1435 	}
1436 	k = error;
1437 	sdp = sg_dev_arr[k];
1438 
1439 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, k), 1);
1440 	if (error)
1441 		goto cdev_add_err;
1442 
1443 	sdp->cdev = cdev;
1444 	if (sg_sysfs_valid) {
1445 		struct class_device * sg_class_member;
1446 
1447 		sg_class_member = class_device_create(sg_sysfs_class, NULL,
1448 				MKDEV(SCSI_GENERIC_MAJOR, k),
1449 				cl_dev->dev, "%s",
1450 				disk->disk_name);
1451 		if (IS_ERR(sg_class_member))
1452 			printk(KERN_WARNING "sg_add: "
1453 				"class_device_create failed\n");
1454 		class_set_devdata(sg_class_member, sdp);
1455 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1456 					  &sg_class_member->kobj, "generic");
1457 		if (error)
1458 			printk(KERN_ERR "sg_add: unable to make symlink "
1459 					"'generic' back to sg%d\n", k);
1460 	} else
1461 		printk(KERN_WARNING "sg_add: sg_sys INvalid\n");
1462 
1463 	sdev_printk(KERN_NOTICE, scsidp,
1464 		    "Attached scsi generic sg%d type %d\n", k,scsidp->type);
1465 
1466 	return 0;
1467 
1468 cdev_add_err:
1469 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
1470 	kfree(sg_dev_arr[k]);
1471 	sg_dev_arr[k] = NULL;
1472 	sg_nr_dev--;
1473 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1474 
1475 out:
1476 	put_disk(disk);
1477 	if (cdev)
1478 		cdev_del(cdev);
1479 	return error;
1480 }
1481 
1482 static void
1483 sg_remove(struct class_device *cl_dev, struct class_interface *cl_intf)
1484 {
1485 	struct scsi_device *scsidp = to_scsi_device(cl_dev->dev);
1486 	Sg_device *sdp = NULL;
1487 	unsigned long iflags;
1488 	Sg_fd *sfp;
1489 	Sg_fd *tsfp;
1490 	Sg_request *srp;
1491 	Sg_request *tsrp;
1492 	int k, delay;
1493 
1494 	if (NULL == sg_dev_arr)
1495 		return;
1496 	delay = 0;
1497 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
1498 	for (k = 0; k < sg_dev_max; k++) {
1499 		sdp = sg_dev_arr[k];
1500 		if ((NULL == sdp) || (sdp->device != scsidp))
1501 			continue;	/* dirty but lowers nesting */
1502 		if (sdp->headfp) {
1503 			sdp->detached = 1;
1504 			for (sfp = sdp->headfp; sfp; sfp = tsfp) {
1505 				tsfp = sfp->nextfp;
1506 				for (srp = sfp->headrp; srp; srp = tsrp) {
1507 					tsrp = srp->nextrp;
1508 					if (sfp->closed || (0 == sg_srp_done(srp, sfp)))
1509 						sg_finish_rem_req(srp);
1510 				}
1511 				if (sfp->closed) {
1512 					scsi_device_put(sdp->device);
1513 					__sg_remove_sfp(sdp, sfp);
1514 				} else {
1515 					delay = 1;
1516 					wake_up_interruptible(&sfp->read_wait);
1517 					kill_fasync(&sfp->async_qp, SIGPOLL,
1518 						    POLL_HUP);
1519 				}
1520 			}
1521 			SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d, dirty\n", k));
1522 			if (NULL == sdp->headfp) {
1523 				sg_dev_arr[k] = NULL;
1524 			}
1525 		} else {	/* nothing active, simple case */
1526 			SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d\n", k));
1527 			sg_dev_arr[k] = NULL;
1528 		}
1529 		sg_nr_dev--;
1530 		break;
1531 	}
1532 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1533 
1534 	if (sdp) {
1535 		sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1536 		class_device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, k));
1537 		cdev_del(sdp->cdev);
1538 		sdp->cdev = NULL;
1539 		put_disk(sdp->disk);
1540 		sdp->disk = NULL;
1541 		if (NULL == sdp->headfp)
1542 			kfree((char *) sdp);
1543 	}
1544 
1545 	if (delay)
1546 		msleep(10);	/* dirty detach so delay device destruction */
1547 }
1548 
1549 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1550 module_param_named(def_reserved_size, def_reserved_size, int,
1551 		   S_IRUGO | S_IWUSR);
1552 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1553 
1554 MODULE_AUTHOR("Douglas Gilbert");
1555 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1556 MODULE_LICENSE("GPL");
1557 MODULE_VERSION(SG_VERSION_STR);
1558 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1559 
1560 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1561                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1562 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1563 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1564 
1565 static int __init
1566 init_sg(void)
1567 {
1568 	int rc;
1569 
1570 	if (scatter_elem_sz < PAGE_SIZE) {
1571 		scatter_elem_sz = PAGE_SIZE;
1572 		scatter_elem_sz_prev = scatter_elem_sz;
1573 	}
1574 	if (def_reserved_size >= 0)
1575 		sg_big_buff = def_reserved_size;
1576 	else
1577 		def_reserved_size = sg_big_buff;
1578 
1579 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1580 				    SG_MAX_DEVS, "sg");
1581 	if (rc)
1582 		return rc;
1583         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1584         if ( IS_ERR(sg_sysfs_class) ) {
1585 		rc = PTR_ERR(sg_sysfs_class);
1586 		goto err_out;
1587         }
1588 	sg_sysfs_valid = 1;
1589 	rc = scsi_register_interface(&sg_interface);
1590 	if (0 == rc) {
1591 #ifdef CONFIG_SCSI_PROC_FS
1592 		sg_proc_init();
1593 #endif				/* CONFIG_SCSI_PROC_FS */
1594 		return 0;
1595 	}
1596 	class_destroy(sg_sysfs_class);
1597 err_out:
1598 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1599 	return rc;
1600 }
1601 
1602 static void __exit
1603 exit_sg(void)
1604 {
1605 #ifdef CONFIG_SCSI_PROC_FS
1606 	sg_proc_cleanup();
1607 #endif				/* CONFIG_SCSI_PROC_FS */
1608 	scsi_unregister_interface(&sg_interface);
1609 	class_destroy(sg_sysfs_class);
1610 	sg_sysfs_valid = 0;
1611 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1612 				 SG_MAX_DEVS);
1613 	kfree((char *)sg_dev_arr);
1614 	sg_dev_arr = NULL;
1615 	sg_dev_max = 0;
1616 }
1617 
1618 static int
1619 sg_start_req(Sg_request * srp)
1620 {
1621 	int res;
1622 	Sg_fd *sfp = srp->parentfp;
1623 	sg_io_hdr_t *hp = &srp->header;
1624 	int dxfer_len = (int) hp->dxfer_len;
1625 	int dxfer_dir = hp->dxfer_direction;
1626 	Sg_scatter_hold *req_schp = &srp->data;
1627 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1628 
1629 	SCSI_LOG_TIMEOUT(4, printk("sg_start_req: dxfer_len=%d\n", dxfer_len));
1630 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1631 		return 0;
1632 	if (sg_allow_dio && (hp->flags & SG_FLAG_DIRECT_IO) &&
1633 	    (dxfer_dir != SG_DXFER_UNKNOWN) && (0 == hp->iovec_count) &&
1634 	    (!sfp->parentdp->device->host->unchecked_isa_dma)) {
1635 		res = sg_build_direct(srp, sfp, dxfer_len);
1636 		if (res <= 0)	/* -ve -> error, 0 -> done, 1 -> try indirect */
1637 			return res;
1638 	}
1639 	if ((!sg_res_in_use(sfp)) && (dxfer_len <= rsv_schp->bufflen))
1640 		sg_link_reserve(sfp, srp, dxfer_len);
1641 	else {
1642 		res = sg_build_indirect(req_schp, sfp, dxfer_len);
1643 		if (res) {
1644 			sg_remove_scat(req_schp);
1645 			return res;
1646 		}
1647 	}
1648 	return 0;
1649 }
1650 
1651 static void
1652 sg_finish_rem_req(Sg_request * srp)
1653 {
1654 	Sg_fd *sfp = srp->parentfp;
1655 	Sg_scatter_hold *req_schp = &srp->data;
1656 
1657 	SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
1658 	if (srp->res_used)
1659 		sg_unlink_reserve(sfp, srp);
1660 	else
1661 		sg_remove_scat(req_schp);
1662 	sg_remove_request(sfp, srp);
1663 }
1664 
1665 static int
1666 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1667 {
1668 	int sg_bufflen = tablesize * sizeof(struct scatterlist);
1669 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1670 
1671 	/*
1672 	 * TODO: test without low_dma, we should not need it since
1673 	 * the block layer will bounce the buffer for us
1674 	 *
1675 	 * XXX(hch): we shouldn't need GFP_DMA for the actual S/G list.
1676 	 */
1677 	if (sfp->low_dma)
1678 		 gfp_flags |= GFP_DMA;
1679 	schp->buffer = kzalloc(sg_bufflen, gfp_flags);
1680 	if (!schp->buffer)
1681 		return -ENOMEM;
1682 	schp->sglist_len = sg_bufflen;
1683 	return tablesize;	/* number of scat_gath elements allocated */
1684 }
1685 
1686 #ifdef SG_ALLOW_DIO_CODE
1687 /* vvvvvvvv  following code borrowed from st driver's direct IO vvvvvvvvv */
1688 	/* TODO: hopefully we can use the generic block layer code */
1689 
1690 /* Pin down user pages and put them into a scatter gather list. Returns <= 0 if
1691    - mapping of all pages not successful
1692    (i.e., either completely successful or fails)
1693 */
1694 static int
1695 st_map_user_pages(struct scatterlist *sgl, const unsigned int max_pages,
1696 	          unsigned long uaddr, size_t count, int rw)
1697 {
1698 	unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
1699 	unsigned long start = uaddr >> PAGE_SHIFT;
1700 	const int nr_pages = end - start;
1701 	int res, i, j;
1702 	struct page **pages;
1703 
1704 	/* User attempted Overflow! */
1705 	if ((uaddr + count) < uaddr)
1706 		return -EINVAL;
1707 
1708 	/* Too big */
1709         if (nr_pages > max_pages)
1710 		return -ENOMEM;
1711 
1712 	/* Hmm? */
1713 	if (count == 0)
1714 		return 0;
1715 
1716 	if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_ATOMIC)) == NULL)
1717 		return -ENOMEM;
1718 
1719         /* Try to fault in all of the necessary pages */
1720 	down_read(&current->mm->mmap_sem);
1721         /* rw==READ means read from drive, write into memory area */
1722 	res = get_user_pages(
1723 		current,
1724 		current->mm,
1725 		uaddr,
1726 		nr_pages,
1727 		rw == READ,
1728 		0, /* don't force */
1729 		pages,
1730 		NULL);
1731 	up_read(&current->mm->mmap_sem);
1732 
1733 	/* Errors and no page mapped should return here */
1734 	if (res < nr_pages)
1735 		goto out_unmap;
1736 
1737         for (i=0; i < nr_pages; i++) {
1738                 /* FIXME: flush superflous for rw==READ,
1739                  * probably wrong function for rw==WRITE
1740                  */
1741 		flush_dcache_page(pages[i]);
1742 		/* ?? Is locking needed? I don't think so */
1743 		/* if (TestSetPageLocked(pages[i]))
1744 		   goto out_unlock; */
1745         }
1746 
1747 	sgl[0].page = pages[0];
1748 	sgl[0].offset = uaddr & ~PAGE_MASK;
1749 	if (nr_pages > 1) {
1750 		sgl[0].length = PAGE_SIZE - sgl[0].offset;
1751 		count -= sgl[0].length;
1752 		for (i=1; i < nr_pages ; i++) {
1753 			sgl[i].page = pages[i];
1754 			sgl[i].length = count < PAGE_SIZE ? count : PAGE_SIZE;
1755 			count -= PAGE_SIZE;
1756 		}
1757 	}
1758 	else {
1759 		sgl[0].length = count;
1760 	}
1761 
1762 	kfree(pages);
1763 	return nr_pages;
1764 
1765  out_unmap:
1766 	if (res > 0) {
1767 		for (j=0; j < res; j++)
1768 			page_cache_release(pages[j]);
1769 		res = 0;
1770 	}
1771 	kfree(pages);
1772 	return res;
1773 }
1774 
1775 
1776 /* And unmap them... */
1777 static int
1778 st_unmap_user_pages(struct scatterlist *sgl, const unsigned int nr_pages,
1779 		    int dirtied)
1780 {
1781 	int i;
1782 
1783 	for (i=0; i < nr_pages; i++) {
1784 		struct page *page = sgl[i].page;
1785 
1786 		if (dirtied)
1787 			SetPageDirty(page);
1788 		/* unlock_page(page); */
1789 		/* FIXME: cache flush missing for rw==READ
1790 		 * FIXME: call the correct reference counting function
1791 		 */
1792 		page_cache_release(page);
1793 	}
1794 
1795 	return 0;
1796 }
1797 
1798 /* ^^^^^^^^  above code borrowed from st driver's direct IO ^^^^^^^^^ */
1799 #endif
1800 
1801 
1802 /* Returns: -ve -> error, 0 -> done, 1 -> try indirect */
1803 static int
1804 sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len)
1805 {
1806 #ifdef SG_ALLOW_DIO_CODE
1807 	sg_io_hdr_t *hp = &srp->header;
1808 	Sg_scatter_hold *schp = &srp->data;
1809 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1810 	int mx_sc_elems, res;
1811 	struct scsi_device *sdev = sfp->parentdp->device;
1812 
1813 	if (((unsigned long)hp->dxferp &
1814 			queue_dma_alignment(sdev->request_queue)) != 0)
1815 		return 1;
1816 
1817 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1818         if (mx_sc_elems <= 0) {
1819                 return 1;
1820         }
1821 	res = st_map_user_pages(schp->buffer, mx_sc_elems,
1822 				(unsigned long)hp->dxferp, dxfer_len,
1823 				(SG_DXFER_TO_DEV == hp->dxfer_direction) ? 1 : 0);
1824 	if (res <= 0) {
1825 		sg_remove_scat(schp);
1826 		return 1;
1827 	}
1828 	schp->k_use_sg = res;
1829 	schp->dio_in_use = 1;
1830 	hp->info |= SG_INFO_DIRECT_IO;
1831 	return 0;
1832 #else
1833 	return 1;
1834 #endif
1835 }
1836 
1837 static int
1838 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1839 {
1840 	struct scatterlist *sg;
1841 	int ret_sz = 0, k, rem_sz, num, mx_sc_elems;
1842 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1843 	int blk_size = buff_size;
1844 	struct page *p = NULL;
1845 
1846 	if ((blk_size < 0) || (!sfp))
1847 		return -EFAULT;
1848 	if (0 == blk_size)
1849 		++blk_size;	/* don't know why */
1850 /* round request up to next highest SG_SECTOR_SZ byte boundary */
1851 	blk_size = (blk_size + SG_SECTOR_MSK) & (~SG_SECTOR_MSK);
1852 	SCSI_LOG_TIMEOUT(4, printk("sg_build_indirect: buff_size=%d, blk_size=%d\n",
1853 				   buff_size, blk_size));
1854 
1855 	/* N.B. ret_sz carried into this block ... */
1856 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1857 	if (mx_sc_elems < 0)
1858 		return mx_sc_elems;	/* most likely -ENOMEM */
1859 
1860 	num = scatter_elem_sz;
1861 	if (unlikely(num != scatter_elem_sz_prev)) {
1862 		if (num < PAGE_SIZE) {
1863 			scatter_elem_sz = PAGE_SIZE;
1864 			scatter_elem_sz_prev = PAGE_SIZE;
1865 		} else
1866 			scatter_elem_sz_prev = num;
1867 	}
1868 	for (k = 0, sg = schp->buffer, rem_sz = blk_size;
1869 	     (rem_sz > 0) && (k < mx_sc_elems);
1870 	     ++k, rem_sz -= ret_sz, ++sg) {
1871 
1872 		num = (rem_sz > scatter_elem_sz_prev) ?
1873 		      scatter_elem_sz_prev : rem_sz;
1874 		p = sg_page_malloc(num, sfp->low_dma, &ret_sz);
1875 		if (!p)
1876 			return -ENOMEM;
1877 
1878 		if (num == scatter_elem_sz_prev) {
1879 			if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1880 				scatter_elem_sz = ret_sz;
1881 				scatter_elem_sz_prev = ret_sz;
1882 			}
1883 		}
1884 		sg->page = p;
1885 		sg->length = (ret_sz > num) ? num : ret_sz;
1886 
1887 		SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k=%d, num=%d, "
1888 				 "ret_sz=%d\n", k, num, ret_sz));
1889 	}		/* end of for loop */
1890 
1891 	schp->k_use_sg = k;
1892 	SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, "
1893 			 "rem_sz=%d\n", k, rem_sz));
1894 
1895 	schp->bufflen = blk_size;
1896 	if (rem_sz > 0)	/* must have failed */
1897 		return -ENOMEM;
1898 
1899 	return 0;
1900 }
1901 
1902 static int
1903 sg_write_xfer(Sg_request * srp)
1904 {
1905 	sg_io_hdr_t *hp = &srp->header;
1906 	Sg_scatter_hold *schp = &srp->data;
1907 	struct scatterlist *sg = schp->buffer;
1908 	int num_xfer = 0;
1909 	int j, k, onum, usglen, ksglen, res;
1910 	int iovec_count = (int) hp->iovec_count;
1911 	int dxfer_dir = hp->dxfer_direction;
1912 	unsigned char *p;
1913 	unsigned char __user *up;
1914 	int new_interface = ('\0' == hp->interface_id) ? 0 : 1;
1915 
1916 	if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_TO_DEV == dxfer_dir) ||
1917 	    (SG_DXFER_TO_FROM_DEV == dxfer_dir)) {
1918 		num_xfer = (int) (new_interface ? hp->dxfer_len : hp->flags);
1919 		if (schp->bufflen < num_xfer)
1920 			num_xfer = schp->bufflen;
1921 	}
1922 	if ((num_xfer <= 0) || (schp->dio_in_use) ||
1923 	    (new_interface
1924 	     && ((SG_FLAG_NO_DXFER | SG_FLAG_MMAP_IO) & hp->flags)))
1925 		return 0;
1926 
1927 	SCSI_LOG_TIMEOUT(4, printk("sg_write_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n",
1928 			  num_xfer, iovec_count, schp->k_use_sg));
1929 	if (iovec_count) {
1930 		onum = iovec_count;
1931 		if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum))
1932 			return -EFAULT;
1933 	} else
1934 		onum = 1;
1935 
1936 	ksglen = sg->length;
1937 	p = page_address(sg->page);
1938 	for (j = 0, k = 0; j < onum; ++j) {
1939 		res = sg_u_iovec(hp, iovec_count, j, 1, &usglen, &up);
1940 		if (res)
1941 			return res;
1942 
1943 		for (; p; ++sg, ksglen = sg->length,
1944 		     p = page_address(sg->page)) {
1945 			if (usglen <= 0)
1946 				break;
1947 			if (ksglen > usglen) {
1948 				if (usglen >= num_xfer) {
1949 					if (__copy_from_user(p, up, num_xfer))
1950 						return -EFAULT;
1951 					return 0;
1952 				}
1953 				if (__copy_from_user(p, up, usglen))
1954 					return -EFAULT;
1955 				p += usglen;
1956 				ksglen -= usglen;
1957 				break;
1958 			} else {
1959 				if (ksglen >= num_xfer) {
1960 					if (__copy_from_user(p, up, num_xfer))
1961 						return -EFAULT;
1962 					return 0;
1963 				}
1964 				if (__copy_from_user(p, up, ksglen))
1965 					return -EFAULT;
1966 				up += ksglen;
1967 				usglen -= ksglen;
1968 			}
1969 			++k;
1970 			if (k >= schp->k_use_sg)
1971 				return 0;
1972 		}
1973 	}
1974 
1975 	return 0;
1976 }
1977 
1978 static int
1979 sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind,
1980 	   int wr_xf, int *countp, unsigned char __user **up)
1981 {
1982 	int num_xfer = (int) hp->dxfer_len;
1983 	unsigned char __user *p = hp->dxferp;
1984 	int count;
1985 
1986 	if (0 == sg_num) {
1987 		if (wr_xf && ('\0' == hp->interface_id))
1988 			count = (int) hp->flags;	/* holds "old" input_size */
1989 		else
1990 			count = num_xfer;
1991 	} else {
1992 		sg_iovec_t iovec;
1993 		if (__copy_from_user(&iovec, p + ind*SZ_SG_IOVEC, SZ_SG_IOVEC))
1994 			return -EFAULT;
1995 		p = iovec.iov_base;
1996 		count = (int) iovec.iov_len;
1997 	}
1998 	if (!access_ok(wr_xf ? VERIFY_READ : VERIFY_WRITE, p, count))
1999 		return -EFAULT;
2000 	if (up)
2001 		*up = p;
2002 	if (countp)
2003 		*countp = count;
2004 	return 0;
2005 }
2006 
2007 static void
2008 sg_remove_scat(Sg_scatter_hold * schp)
2009 {
2010 	SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
2011 	if (schp->buffer && (schp->sglist_len > 0)) {
2012 		struct scatterlist *sg = schp->buffer;
2013 
2014 		if (schp->dio_in_use) {
2015 #ifdef SG_ALLOW_DIO_CODE
2016 			st_unmap_user_pages(sg, schp->k_use_sg, TRUE);
2017 #endif
2018 		} else {
2019 			int k;
2020 
2021 			for (k = 0; (k < schp->k_use_sg) && sg->page;
2022 			     ++k, ++sg) {
2023 				SCSI_LOG_TIMEOUT(5, printk(
2024 				    "sg_remove_scat: k=%d, pg=0x%p, len=%d\n",
2025 				    k, sg->page, sg->length));
2026 				sg_page_free(sg->page, sg->length);
2027 			}
2028 		}
2029 		kfree(schp->buffer);
2030 	}
2031 	memset(schp, 0, sizeof (*schp));
2032 }
2033 
2034 static int
2035 sg_read_xfer(Sg_request * srp)
2036 {
2037 	sg_io_hdr_t *hp = &srp->header;
2038 	Sg_scatter_hold *schp = &srp->data;
2039 	struct scatterlist *sg = schp->buffer;
2040 	int num_xfer = 0;
2041 	int j, k, onum, usglen, ksglen, res;
2042 	int iovec_count = (int) hp->iovec_count;
2043 	int dxfer_dir = hp->dxfer_direction;
2044 	unsigned char *p;
2045 	unsigned char __user *up;
2046 	int new_interface = ('\0' == hp->interface_id) ? 0 : 1;
2047 
2048 	if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_FROM_DEV == dxfer_dir)
2049 	    || (SG_DXFER_TO_FROM_DEV == dxfer_dir)) {
2050 		num_xfer = hp->dxfer_len;
2051 		if (schp->bufflen < num_xfer)
2052 			num_xfer = schp->bufflen;
2053 	}
2054 	if ((num_xfer <= 0) || (schp->dio_in_use) ||
2055 	    (new_interface
2056 	     && ((SG_FLAG_NO_DXFER | SG_FLAG_MMAP_IO) & hp->flags)))
2057 		return 0;
2058 
2059 	SCSI_LOG_TIMEOUT(4, printk("sg_read_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n",
2060 			  num_xfer, iovec_count, schp->k_use_sg));
2061 	if (iovec_count) {
2062 		onum = iovec_count;
2063 		if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum))
2064 			return -EFAULT;
2065 	} else
2066 		onum = 1;
2067 
2068 	p = page_address(sg->page);
2069 	ksglen = sg->length;
2070 	for (j = 0, k = 0; j < onum; ++j) {
2071 		res = sg_u_iovec(hp, iovec_count, j, 0, &usglen, &up);
2072 		if (res)
2073 			return res;
2074 
2075 		for (; p; ++sg, ksglen = sg->length,
2076 		     p = page_address(sg->page)) {
2077 			if (usglen <= 0)
2078 				break;
2079 			if (ksglen > usglen) {
2080 				if (usglen >= num_xfer) {
2081 					if (__copy_to_user(up, p, num_xfer))
2082 						return -EFAULT;
2083 					return 0;
2084 				}
2085 				if (__copy_to_user(up, p, usglen))
2086 					return -EFAULT;
2087 				p += usglen;
2088 				ksglen -= usglen;
2089 				break;
2090 			} else {
2091 				if (ksglen >= num_xfer) {
2092 					if (__copy_to_user(up, p, num_xfer))
2093 						return -EFAULT;
2094 					return 0;
2095 				}
2096 				if (__copy_to_user(up, p, ksglen))
2097 					return -EFAULT;
2098 				up += ksglen;
2099 				usglen -= ksglen;
2100 			}
2101 			++k;
2102 			if (k >= schp->k_use_sg)
2103 				return 0;
2104 		}
2105 	}
2106 
2107 	return 0;
2108 }
2109 
2110 static int
2111 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
2112 {
2113 	Sg_scatter_hold *schp = &srp->data;
2114 	struct scatterlist *sg = schp->buffer;
2115 	int k, num;
2116 
2117 	SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n",
2118 				   num_read_xfer));
2119 	if ((!outp) || (num_read_xfer <= 0))
2120 		return 0;
2121 
2122 	for (k = 0; (k < schp->k_use_sg) && sg->page; ++k, ++sg) {
2123 		num = sg->length;
2124 		if (num > num_read_xfer) {
2125 			if (__copy_to_user(outp, page_address(sg->page),
2126 					   num_read_xfer))
2127 				return -EFAULT;
2128 			break;
2129 		} else {
2130 			if (__copy_to_user(outp, page_address(sg->page),
2131 					   num))
2132 				return -EFAULT;
2133 			num_read_xfer -= num;
2134 			if (num_read_xfer <= 0)
2135 				break;
2136 			outp += num;
2137 		}
2138 	}
2139 
2140 	return 0;
2141 }
2142 
2143 static void
2144 sg_build_reserve(Sg_fd * sfp, int req_size)
2145 {
2146 	Sg_scatter_hold *schp = &sfp->reserve;
2147 
2148 	SCSI_LOG_TIMEOUT(4, printk("sg_build_reserve: req_size=%d\n", req_size));
2149 	do {
2150 		if (req_size < PAGE_SIZE)
2151 			req_size = PAGE_SIZE;
2152 		if (0 == sg_build_indirect(schp, sfp, req_size))
2153 			return;
2154 		else
2155 			sg_remove_scat(schp);
2156 		req_size >>= 1;	/* divide by 2 */
2157 	} while (req_size > (PAGE_SIZE / 2));
2158 }
2159 
2160 static void
2161 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
2162 {
2163 	Sg_scatter_hold *req_schp = &srp->data;
2164 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
2165 	struct scatterlist *sg = rsv_schp->buffer;
2166 	int k, num, rem;
2167 
2168 	srp->res_used = 1;
2169 	SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
2170 	rem = size;
2171 
2172 	for (k = 0; k < rsv_schp->k_use_sg; ++k, ++sg) {
2173 		num = sg->length;
2174 		if (rem <= num) {
2175 			sfp->save_scat_len = num;
2176 			sg->length = rem;
2177 			req_schp->k_use_sg = k + 1;
2178 			req_schp->sglist_len = rsv_schp->sglist_len;
2179 			req_schp->buffer = rsv_schp->buffer;
2180 
2181 			req_schp->bufflen = size;
2182 			req_schp->b_malloc_len = rsv_schp->b_malloc_len;
2183 			break;
2184 		} else
2185 			rem -= num;
2186 	}
2187 
2188 	if (k >= rsv_schp->k_use_sg)
2189 		SCSI_LOG_TIMEOUT(1, printk("sg_link_reserve: BAD size\n"));
2190 }
2191 
2192 static void
2193 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2194 {
2195 	Sg_scatter_hold *req_schp = &srp->data;
2196 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
2197 
2198 	SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n",
2199 				   (int) req_schp->k_use_sg));
2200 	if ((rsv_schp->k_use_sg > 0) && (req_schp->k_use_sg > 0)) {
2201 		struct scatterlist *sg = rsv_schp->buffer;
2202 
2203 		if (sfp->save_scat_len > 0)
2204 			(sg + (req_schp->k_use_sg - 1))->length =
2205 			    (unsigned) sfp->save_scat_len;
2206 		else
2207 			SCSI_LOG_TIMEOUT(1, printk ("sg_unlink_reserve: BAD save_scat_len\n"));
2208 	}
2209 	req_schp->k_use_sg = 0;
2210 	req_schp->bufflen = 0;
2211 	req_schp->buffer = NULL;
2212 	req_schp->sglist_len = 0;
2213 	sfp->save_scat_len = 0;
2214 	srp->res_used = 0;
2215 }
2216 
2217 static Sg_request *
2218 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2219 {
2220 	Sg_request *resp;
2221 	unsigned long iflags;
2222 
2223 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2224 	for (resp = sfp->headrp; resp; resp = resp->nextrp) {
2225 		/* look for requests that are ready + not SG_IO owned */
2226 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
2227 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2228 			resp->done = 2;	/* guard against other readers */
2229 			break;
2230 		}
2231 	}
2232 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2233 	return resp;
2234 }
2235 
2236 #ifdef CONFIG_SCSI_PROC_FS
2237 static Sg_request *
2238 sg_get_nth_request(Sg_fd * sfp, int nth)
2239 {
2240 	Sg_request *resp;
2241 	unsigned long iflags;
2242 	int k;
2243 
2244 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2245 	for (k = 0, resp = sfp->headrp; resp && (k < nth);
2246 	     ++k, resp = resp->nextrp) ;
2247 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2248 	return resp;
2249 }
2250 #endif
2251 
2252 /* always adds to end of list */
2253 static Sg_request *
2254 sg_add_request(Sg_fd * sfp)
2255 {
2256 	int k;
2257 	unsigned long iflags;
2258 	Sg_request *resp;
2259 	Sg_request *rp = sfp->req_arr;
2260 
2261 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2262 	resp = sfp->headrp;
2263 	if (!resp) {
2264 		memset(rp, 0, sizeof (Sg_request));
2265 		rp->parentfp = sfp;
2266 		resp = rp;
2267 		sfp->headrp = resp;
2268 	} else {
2269 		if (0 == sfp->cmd_q)
2270 			resp = NULL;	/* command queuing disallowed */
2271 		else {
2272 			for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2273 				if (!rp->parentfp)
2274 					break;
2275 			}
2276 			if (k < SG_MAX_QUEUE) {
2277 				memset(rp, 0, sizeof (Sg_request));
2278 				rp->parentfp = sfp;
2279 				while (resp->nextrp)
2280 					resp = resp->nextrp;
2281 				resp->nextrp = rp;
2282 				resp = rp;
2283 			} else
2284 				resp = NULL;
2285 		}
2286 	}
2287 	if (resp) {
2288 		resp->nextrp = NULL;
2289 		resp->header.duration = jiffies_to_msecs(jiffies);
2290 	}
2291 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2292 	return resp;
2293 }
2294 
2295 /* Return of 1 for found; 0 for not found */
2296 static int
2297 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2298 {
2299 	Sg_request *prev_rp;
2300 	Sg_request *rp;
2301 	unsigned long iflags;
2302 	int res = 0;
2303 
2304 	if ((!sfp) || (!srp) || (!sfp->headrp))
2305 		return res;
2306 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2307 	prev_rp = sfp->headrp;
2308 	if (srp == prev_rp) {
2309 		sfp->headrp = prev_rp->nextrp;
2310 		prev_rp->parentfp = NULL;
2311 		res = 1;
2312 	} else {
2313 		while ((rp = prev_rp->nextrp)) {
2314 			if (srp == rp) {
2315 				prev_rp->nextrp = rp->nextrp;
2316 				rp->parentfp = NULL;
2317 				res = 1;
2318 				break;
2319 			}
2320 			prev_rp = rp;
2321 		}
2322 	}
2323 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2324 	return res;
2325 }
2326 
2327 #ifdef CONFIG_SCSI_PROC_FS
2328 static Sg_fd *
2329 sg_get_nth_sfp(Sg_device * sdp, int nth)
2330 {
2331 	Sg_fd *resp;
2332 	unsigned long iflags;
2333 	int k;
2334 
2335 	read_lock_irqsave(&sg_dev_arr_lock, iflags);
2336 	for (k = 0, resp = sdp->headfp; resp && (k < nth);
2337 	     ++k, resp = resp->nextfp) ;
2338 	read_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2339 	return resp;
2340 }
2341 #endif
2342 
2343 static Sg_fd *
2344 sg_add_sfp(Sg_device * sdp, int dev)
2345 {
2346 	Sg_fd *sfp;
2347 	unsigned long iflags;
2348 	int bufflen;
2349 
2350 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2351 	if (!sfp)
2352 		return NULL;
2353 
2354 	init_waitqueue_head(&sfp->read_wait);
2355 	rwlock_init(&sfp->rq_list_lock);
2356 
2357 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2358 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2359 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2360 	sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2361 	    sdp->device->host->unchecked_isa_dma : 1;
2362 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2363 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2364 	sfp->parentdp = sdp;
2365 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
2366 	if (!sdp->headfp)
2367 		sdp->headfp = sfp;
2368 	else {			/* add to tail of existing list */
2369 		Sg_fd *pfp = sdp->headfp;
2370 		while (pfp->nextfp)
2371 			pfp = pfp->nextfp;
2372 		pfp->nextfp = sfp;
2373 	}
2374 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2375 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
2376 	if (unlikely(sg_big_buff != def_reserved_size))
2377 		sg_big_buff = def_reserved_size;
2378 
2379 	bufflen = min_t(int, sg_big_buff,
2380 			sdp->device->request_queue->max_sectors * 512);
2381 	sg_build_reserve(sfp, bufflen);
2382 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp:   bufflen=%d, k_use_sg=%d\n",
2383 			   sfp->reserve.bufflen, sfp->reserve.k_use_sg));
2384 	return sfp;
2385 }
2386 
2387 static void
2388 __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2389 {
2390 	Sg_fd *fp;
2391 	Sg_fd *prev_fp;
2392 
2393 	prev_fp = sdp->headfp;
2394 	if (sfp == prev_fp)
2395 		sdp->headfp = prev_fp->nextfp;
2396 	else {
2397 		while ((fp = prev_fp->nextfp)) {
2398 			if (sfp == fp) {
2399 				prev_fp->nextfp = fp->nextfp;
2400 				break;
2401 			}
2402 			prev_fp = fp;
2403 		}
2404 	}
2405 	if (sfp->reserve.bufflen > 0) {
2406 		SCSI_LOG_TIMEOUT(6,
2407 			printk("__sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2408 			(int) sfp->reserve.bufflen, (int) sfp->reserve.k_use_sg));
2409 		sg_remove_scat(&sfp->reserve);
2410 	}
2411 	sfp->parentdp = NULL;
2412 	SCSI_LOG_TIMEOUT(6, printk("__sg_remove_sfp:    sfp=0x%p\n", sfp));
2413 	kfree(sfp);
2414 }
2415 
2416 /* Returns 0 in normal case, 1 when detached and sdp object removed */
2417 static int
2418 sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2419 {
2420 	Sg_request *srp;
2421 	Sg_request *tsrp;
2422 	int dirty = 0;
2423 	int res = 0;
2424 
2425 	for (srp = sfp->headrp; srp; srp = tsrp) {
2426 		tsrp = srp->nextrp;
2427 		if (sg_srp_done(srp, sfp))
2428 			sg_finish_rem_req(srp);
2429 		else
2430 			++dirty;
2431 	}
2432 	if (0 == dirty) {
2433 		unsigned long iflags;
2434 
2435 		write_lock_irqsave(&sg_dev_arr_lock, iflags);
2436 		__sg_remove_sfp(sdp, sfp);
2437 		if (sdp->detached && (NULL == sdp->headfp)) {
2438 			int k, maxd;
2439 
2440 			maxd = sg_dev_max;
2441 			for (k = 0; k < maxd; ++k) {
2442 				if (sdp == sg_dev_arr[k])
2443 					break;
2444 			}
2445 			if (k < maxd)
2446 				sg_dev_arr[k] = NULL;
2447 			kfree((char *) sdp);
2448 			res = 1;
2449 		}
2450 		write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2451 	} else {
2452 		/* MOD_INC's to inhibit unloading sg and associated adapter driver */
2453 		/* only bump the access_count if we actually succeeded in
2454 		 * throwing another counter on the host module */
2455 		scsi_device_get(sdp->device);	/* XXX: retval ignored? */
2456 		sfp->closed = 1;	/* flag dirty state on this fd */
2457 		SCSI_LOG_TIMEOUT(1, printk("sg_remove_sfp: worrisome, %d writes pending\n",
2458 				  dirty));
2459 	}
2460 	return res;
2461 }
2462 
2463 static int
2464 sg_res_in_use(Sg_fd * sfp)
2465 {
2466 	const Sg_request *srp;
2467 	unsigned long iflags;
2468 
2469 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2470 	for (srp = sfp->headrp; srp; srp = srp->nextrp)
2471 		if (srp->res_used)
2472 			break;
2473 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2474 	return srp ? 1 : 0;
2475 }
2476 
2477 /* The size fetched (value output via retSzp) set when non-NULL return */
2478 static struct page *
2479 sg_page_malloc(int rqSz, int lowDma, int *retSzp)
2480 {
2481 	struct page *resp = NULL;
2482 	gfp_t page_mask;
2483 	int order, a_size;
2484 	int resSz;
2485 
2486 	if ((rqSz <= 0) || (NULL == retSzp))
2487 		return resp;
2488 
2489 	if (lowDma)
2490 		page_mask = GFP_ATOMIC | GFP_DMA | __GFP_COMP | __GFP_NOWARN;
2491 	else
2492 		page_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
2493 
2494 	for (order = 0, a_size = PAGE_SIZE; a_size < rqSz;
2495 	     order++, a_size <<= 1) ;
2496 	resSz = a_size;		/* rounded up if necessary */
2497 	resp = alloc_pages(page_mask, order);
2498 	while ((!resp) && order) {
2499 		--order;
2500 		a_size >>= 1;	/* divide by 2, until PAGE_SIZE */
2501 		resp =  alloc_pages(page_mask, order);	/* try half */
2502 		resSz = a_size;
2503 	}
2504 	if (resp) {
2505 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2506 			memset(page_address(resp), 0, resSz);
2507 		*retSzp = resSz;
2508 	}
2509 	return resp;
2510 }
2511 
2512 static void
2513 sg_page_free(struct page *page, int size)
2514 {
2515 	int order, a_size;
2516 
2517 	if (!page)
2518 		return;
2519 	for (order = 0, a_size = PAGE_SIZE; a_size < size;
2520 	     order++, a_size <<= 1) ;
2521 	__free_pages(page, order);
2522 }
2523 
2524 #ifndef MAINTENANCE_IN_CMD
2525 #define MAINTENANCE_IN_CMD 0xa3
2526 #endif
2527 
2528 static unsigned char allow_ops[] = { TEST_UNIT_READY, REQUEST_SENSE,
2529 	INQUIRY, READ_CAPACITY, READ_BUFFER, READ_6, READ_10, READ_12,
2530 	READ_16, MODE_SENSE, MODE_SENSE_10, LOG_SENSE, REPORT_LUNS,
2531 	SERVICE_ACTION_IN, RECEIVE_DIAGNOSTIC, READ_LONG, MAINTENANCE_IN_CMD
2532 };
2533 
2534 static int
2535 sg_allow_access(unsigned char opcode, char dev_type)
2536 {
2537 	int k;
2538 
2539 	if (TYPE_SCANNER == dev_type)	/* TYPE_ROM maybe burner */
2540 		return 1;
2541 	for (k = 0; k < sizeof (allow_ops); ++k) {
2542 		if (opcode == allow_ops[k])
2543 			return 1;
2544 	}
2545 	return 0;
2546 }
2547 
2548 #ifdef CONFIG_SCSI_PROC_FS
2549 static int
2550 sg_last_dev(void)
2551 {
2552 	int k;
2553 	unsigned long iflags;
2554 
2555 	read_lock_irqsave(&sg_dev_arr_lock, iflags);
2556 	for (k = sg_dev_max - 1; k >= 0; --k)
2557 		if (sg_dev_arr[k] && sg_dev_arr[k]->device)
2558 			break;
2559 	read_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2560 	return k + 1;		/* origin 1 */
2561 }
2562 #endif
2563 
2564 static Sg_device *
2565 sg_get_dev(int dev)
2566 {
2567 	Sg_device *sdp = NULL;
2568 	unsigned long iflags;
2569 
2570 	if (sg_dev_arr && (dev >= 0)) {
2571 		read_lock_irqsave(&sg_dev_arr_lock, iflags);
2572 		if (dev < sg_dev_max)
2573 			sdp = sg_dev_arr[dev];
2574 		read_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2575 	}
2576 	return sdp;
2577 }
2578 
2579 #ifdef CONFIG_SCSI_PROC_FS
2580 
2581 static struct proc_dir_entry *sg_proc_sgp = NULL;
2582 
2583 static char sg_proc_sg_dirname[] = "scsi/sg";
2584 
2585 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2586 
2587 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2588 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2589 			          size_t count, loff_t *off);
2590 static struct file_operations adio_fops = {
2591 	/* .owner, .read and .llseek added in sg_proc_init() */
2592 	.open = sg_proc_single_open_adio,
2593 	.write = sg_proc_write_adio,
2594 	.release = single_release,
2595 };
2596 
2597 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2598 static ssize_t sg_proc_write_dressz(struct file *filp,
2599 		const char __user *buffer, size_t count, loff_t *off);
2600 static struct file_operations dressz_fops = {
2601 	.open = sg_proc_single_open_dressz,
2602 	.write = sg_proc_write_dressz,
2603 	.release = single_release,
2604 };
2605 
2606 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2607 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2608 static struct file_operations version_fops = {
2609 	.open = sg_proc_single_open_version,
2610 	.release = single_release,
2611 };
2612 
2613 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2614 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2615 static struct file_operations devhdr_fops = {
2616 	.open = sg_proc_single_open_devhdr,
2617 	.release = single_release,
2618 };
2619 
2620 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2621 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2622 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2623 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2624 static void dev_seq_stop(struct seq_file *s, void *v);
2625 static struct file_operations dev_fops = {
2626 	.open = sg_proc_open_dev,
2627 	.release = seq_release,
2628 };
2629 static struct seq_operations dev_seq_ops = {
2630 	.start = dev_seq_start,
2631 	.next  = dev_seq_next,
2632 	.stop  = dev_seq_stop,
2633 	.show  = sg_proc_seq_show_dev,
2634 };
2635 
2636 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2637 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2638 static struct file_operations devstrs_fops = {
2639 	.open = sg_proc_open_devstrs,
2640 	.release = seq_release,
2641 };
2642 static struct seq_operations devstrs_seq_ops = {
2643 	.start = dev_seq_start,
2644 	.next  = dev_seq_next,
2645 	.stop  = dev_seq_stop,
2646 	.show  = sg_proc_seq_show_devstrs,
2647 };
2648 
2649 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2650 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2651 static struct file_operations debug_fops = {
2652 	.open = sg_proc_open_debug,
2653 	.release = seq_release,
2654 };
2655 static struct seq_operations debug_seq_ops = {
2656 	.start = dev_seq_start,
2657 	.next  = dev_seq_next,
2658 	.stop  = dev_seq_stop,
2659 	.show  = sg_proc_seq_show_debug,
2660 };
2661 
2662 
2663 struct sg_proc_leaf {
2664 	const char * name;
2665 	struct file_operations * fops;
2666 };
2667 
2668 static struct sg_proc_leaf sg_proc_leaf_arr[] = {
2669 	{"allow_dio", &adio_fops},
2670 	{"debug", &debug_fops},
2671 	{"def_reserved_size", &dressz_fops},
2672 	{"device_hdr", &devhdr_fops},
2673 	{"devices", &dev_fops},
2674 	{"device_strs", &devstrs_fops},
2675 	{"version", &version_fops}
2676 };
2677 
2678 static int
2679 sg_proc_init(void)
2680 {
2681 	int k, mask;
2682 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2683 	struct proc_dir_entry *pdep;
2684 	struct sg_proc_leaf * leaf;
2685 
2686 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2687 	if (!sg_proc_sgp)
2688 		return 1;
2689 	for (k = 0; k < num_leaves; ++k) {
2690 		leaf = &sg_proc_leaf_arr[k];
2691 		mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2692 		pdep = create_proc_entry(leaf->name, mask, sg_proc_sgp);
2693 		if (pdep) {
2694 			leaf->fops->owner = THIS_MODULE,
2695 			leaf->fops->read = seq_read,
2696 			leaf->fops->llseek = seq_lseek,
2697 			pdep->proc_fops = leaf->fops;
2698 		}
2699 	}
2700 	return 0;
2701 }
2702 
2703 static void
2704 sg_proc_cleanup(void)
2705 {
2706 	int k;
2707 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2708 
2709 	if (!sg_proc_sgp)
2710 		return;
2711 	for (k = 0; k < num_leaves; ++k)
2712 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2713 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2714 }
2715 
2716 
2717 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2718 {
2719 	seq_printf(s, "%d\n", *((int *)s->private));
2720 	return 0;
2721 }
2722 
2723 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2724 {
2725 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2726 }
2727 
2728 static ssize_t
2729 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2730 		   size_t count, loff_t *off)
2731 {
2732 	int num;
2733 	char buff[11];
2734 
2735 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2736 		return -EACCES;
2737 	num = (count < 10) ? count : 10;
2738 	if (copy_from_user(buff, buffer, num))
2739 		return -EFAULT;
2740 	buff[num] = '\0';
2741 	sg_allow_dio = simple_strtoul(buff, NULL, 10) ? 1 : 0;
2742 	return count;
2743 }
2744 
2745 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2746 {
2747 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2748 }
2749 
2750 static ssize_t
2751 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2752 		     size_t count, loff_t *off)
2753 {
2754 	int num;
2755 	unsigned long k = ULONG_MAX;
2756 	char buff[11];
2757 
2758 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2759 		return -EACCES;
2760 	num = (count < 10) ? count : 10;
2761 	if (copy_from_user(buff, buffer, num))
2762 		return -EFAULT;
2763 	buff[num] = '\0';
2764 	k = simple_strtoul(buff, NULL, 10);
2765 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2766 		sg_big_buff = k;
2767 		return count;
2768 	}
2769 	return -ERANGE;
2770 }
2771 
2772 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2773 {
2774 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2775 		   sg_version_date);
2776 	return 0;
2777 }
2778 
2779 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2780 {
2781 	return single_open(file, sg_proc_seq_show_version, NULL);
2782 }
2783 
2784 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2785 {
2786 	seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
2787 		   "online\n");
2788 	return 0;
2789 }
2790 
2791 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2792 {
2793 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2794 }
2795 
2796 struct sg_proc_deviter {
2797 	loff_t	index;
2798 	size_t	max;
2799 };
2800 
2801 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2802 {
2803 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2804 
2805 	s->private = it;
2806 	if (! it)
2807 		return NULL;
2808 
2809 	if (NULL == sg_dev_arr)
2810 		return NULL;
2811 	it->index = *pos;
2812 	it->max = sg_last_dev();
2813 	if (it->index >= it->max)
2814 		return NULL;
2815 	return it;
2816 }
2817 
2818 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2819 {
2820 	struct sg_proc_deviter * it = s->private;
2821 
2822 	*pos = ++it->index;
2823 	return (it->index < it->max) ? it : NULL;
2824 }
2825 
2826 static void dev_seq_stop(struct seq_file *s, void *v)
2827 {
2828 	kfree(s->private);
2829 }
2830 
2831 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2832 {
2833         return seq_open(file, &dev_seq_ops);
2834 }
2835 
2836 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2837 {
2838 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2839 	Sg_device *sdp;
2840 	struct scsi_device *scsidp;
2841 
2842 	sdp = it ? sg_get_dev(it->index) : NULL;
2843 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2844 		seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
2845 			      scsidp->host->host_no, scsidp->channel,
2846 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2847 			      1,
2848 			      (int) scsidp->queue_depth,
2849 			      (int) scsidp->device_busy,
2850 			      (int) scsi_device_online(scsidp));
2851 	else
2852 		seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2853 	return 0;
2854 }
2855 
2856 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2857 {
2858         return seq_open(file, &devstrs_seq_ops);
2859 }
2860 
2861 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2862 {
2863 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2864 	Sg_device *sdp;
2865 	struct scsi_device *scsidp;
2866 
2867 	sdp = it ? sg_get_dev(it->index) : NULL;
2868 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2869 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2870 			   scsidp->vendor, scsidp->model, scsidp->rev);
2871 	else
2872 		seq_printf(s, "<no active device>\n");
2873 	return 0;
2874 }
2875 
2876 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2877 {
2878 	int k, m, new_interface, blen, usg;
2879 	Sg_request *srp;
2880 	Sg_fd *fp;
2881 	const sg_io_hdr_t *hp;
2882 	const char * cp;
2883 	unsigned int ms;
2884 
2885 	for (k = 0; (fp = sg_get_nth_sfp(sdp, k)); ++k) {
2886 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2887 			   "(res)sgat=%d low_dma=%d\n", k + 1,
2888 			   jiffies_to_msecs(fp->timeout),
2889 			   fp->reserve.bufflen,
2890 			   (int) fp->reserve.k_use_sg,
2891 			   (int) fp->low_dma);
2892 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=%d\n",
2893 			   (int) fp->cmd_q, (int) fp->force_packid,
2894 			   (int) fp->keep_orphan, (int) fp->closed);
2895 		for (m = 0; (srp = sg_get_nth_request(fp, m)); ++m) {
2896 			hp = &srp->header;
2897 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2898 			if (srp->res_used) {
2899 				if (new_interface &&
2900 				    (SG_FLAG_MMAP_IO & hp->flags))
2901 					cp = "     mmap>> ";
2902 				else
2903 					cp = "     rb>> ";
2904 			} else {
2905 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2906 					cp = "     dio>> ";
2907 				else
2908 					cp = "     ";
2909 			}
2910 			seq_printf(s, cp);
2911 			blen = srp->data.bufflen;
2912 			usg = srp->data.k_use_sg;
2913 			seq_printf(s, srp->done ?
2914 				   ((1 == srp->done) ?  "rcv:" : "fin:")
2915 				   : "act:");
2916 			seq_printf(s, " id=%d blen=%d",
2917 				   srp->header.pack_id, blen);
2918 			if (srp->done)
2919 				seq_printf(s, " dur=%d", hp->duration);
2920 			else {
2921 				ms = jiffies_to_msecs(jiffies);
2922 				seq_printf(s, " t_o/elap=%d/%d",
2923 					(new_interface ? hp->timeout :
2924 						  jiffies_to_msecs(fp->timeout)),
2925 					(ms > hp->duration ? ms - hp->duration : 0));
2926 			}
2927 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2928 				   (int) srp->data.cmd_opcode);
2929 		}
2930 		if (0 == m)
2931 			seq_printf(s, "     No requests active\n");
2932 	}
2933 }
2934 
2935 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2936 {
2937         return seq_open(file, &debug_seq_ops);
2938 }
2939 
2940 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2941 {
2942 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2943 	Sg_device *sdp;
2944 
2945 	if (it && (0 == it->index)) {
2946 		seq_printf(s, "dev_max(currently)=%d max_active_device=%d "
2947 			   "(origin 1)\n", sg_dev_max, (int)it->max);
2948 		seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
2949 	}
2950 	sdp = it ? sg_get_dev(it->index) : NULL;
2951 	if (sdp) {
2952 		struct scsi_device *scsidp = sdp->device;
2953 
2954 		if (NULL == scsidp) {
2955 			seq_printf(s, "device %d detached ??\n",
2956 				   (int)it->index);
2957 			return 0;
2958 		}
2959 
2960 		if (sg_get_nth_sfp(sdp, 0)) {
2961 			seq_printf(s, " >>> device=%s ",
2962 				sdp->disk->disk_name);
2963 			if (sdp->detached)
2964 				seq_printf(s, "detached pending close ");
2965 			else
2966 				seq_printf
2967 				    (s, "scsi%d chan=%d id=%d lun=%d   em=%d",
2968 				     scsidp->host->host_no,
2969 				     scsidp->channel, scsidp->id,
2970 				     scsidp->lun,
2971 				     scsidp->host->hostt->emulated);
2972 			seq_printf(s, " sg_tablesize=%d excl=%d\n",
2973 				   sdp->sg_tablesize, sdp->exclude);
2974 		}
2975 		sg_proc_debug_helper(s, sdp);
2976 	}
2977 	return 0;
2978 }
2979 
2980 #endif				/* CONFIG_SCSI_PROC_FS */
2981 
2982 module_init(init_sg);
2983 module_exit(exit_sg);
2984