xref: /linux/drivers/scsi/sg.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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 = 30533;	/* 2 digits for each component */
22 #define SG_VERSION_STR "3.5.33"
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/config.h>
32 #include <linux/module.h>
33 
34 #include <linux/fs.h>
35 #include <linux/kernel.h>
36 #include <linux/sched.h>
37 #include <linux/string.h>
38 #include <linux/mm.h>
39 #include <linux/errno.h>
40 #include <linux/mtio.h>
41 #include <linux/ioctl.h>
42 #include <linux/fcntl.h>
43 #include <linux/init.h>
44 #include <linux/poll.h>
45 #include <linux/smp_lock.h>
46 #include <linux/moduleparam.h>
47 #include <linux/cdev.h>
48 #include <linux/seq_file.h>
49 #include <linux/blkdev.h>
50 #include <linux/delay.h>
51 #include <linux/scatterlist.h>
52 
53 #include "scsi.h"
54 #include <scsi/scsi_dbg.h>
55 #include <scsi/scsi_host.h>
56 #include <scsi/scsi_driver.h>
57 #include <scsi/scsi_ioctl.h>
58 #include <scsi/sg.h>
59 
60 #include "scsi_logging.h"
61 
62 #ifdef CONFIG_SCSI_PROC_FS
63 #include <linux/proc_fs.h>
64 static char *sg_version_date = "20050908";
65 
66 static int sg_proc_init(void);
67 static void sg_proc_cleanup(void);
68 #endif
69 
70 #define SG_ALLOW_DIO_DEF 0
71 #define SG_ALLOW_DIO_CODE /* compile out by commenting this define */
72 
73 #define SG_MAX_DEVS 32768
74 
75 /*
76  * Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
77  * Then when using 32 bit integers x * m may overflow during the calculation.
78  * Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m
79  * calculates the same, but prevents the overflow when both m and d
80  * are "small" numbers (like HZ and USER_HZ).
81  * Of course an overflow is inavoidable if the result of muldiv doesn't fit
82  * in 32 bits.
83  */
84 #define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))
85 
86 #define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
87 
88 int sg_big_buff = SG_DEF_RESERVED_SIZE;
89 /* N.B. This variable is readable and writeable via
90    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
91    of this size (or less if there is not enough memory) will be reserved
92    for use by this file descriptor. [Deprecated usage: this variable is also
93    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
94    the kernel (i.e. it is not a module).] */
95 static int def_reserved_size = -1;	/* picks up init parameter */
96 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
97 
98 #define SG_SECTOR_SZ 512
99 #define SG_SECTOR_MSK (SG_SECTOR_SZ - 1)
100 
101 #define SG_DEV_ARR_LUMP 32	/* amount to over allocate sg_dev_arr by */
102 
103 static int sg_add(struct class_device *, struct class_interface *);
104 static void sg_remove(struct class_device *, struct class_interface *);
105 
106 static DEFINE_RWLOCK(sg_dev_arr_lock);	/* Also used to lock
107 							   file descriptor list for device */
108 
109 static struct class_interface sg_interface = {
110 	.add		= sg_add,
111 	.remove		= sg_remove,
112 };
113 
114 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
115 	unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
116 	unsigned short sglist_len; /* size of malloc'd scatter-gather list ++ */
117 	unsigned bufflen;	/* Size of (aggregate) data buffer */
118 	unsigned b_malloc_len;	/* actual len malloc'ed in buffer */
119 	struct scatterlist *buffer;/* scatter list */
120 	char dio_in_use;	/* 0->indirect IO (or mmap), 1->dio */
121 	unsigned char cmd_opcode; /* first byte of command */
122 } Sg_scatter_hold;
123 
124 struct sg_device;		/* forward declarations */
125 struct sg_fd;
126 
127 typedef struct sg_request {	/* SG_MAX_QUEUE requests outstanding per file */
128 	struct sg_request *nextrp;	/* NULL -> tail request (slist) */
129 	struct sg_fd *parentfp;	/* NULL -> not in use */
130 	Sg_scatter_hold data;	/* hold buffer, perhaps scatter list */
131 	sg_io_hdr_t header;	/* scsi command+info, see <scsi/sg.h> */
132 	unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
133 	char res_used;		/* 1 -> using reserve buffer, 0 -> not ... */
134 	char orphan;		/* 1 -> drop on sight, 0 -> normal */
135 	char sg_io_owned;	/* 1 -> packet belongs to SG_IO */
136 	volatile char done;	/* 0->before bh, 1->before read, 2->read */
137 } Sg_request;
138 
139 typedef struct sg_fd {		/* holds the state of a file descriptor */
140 	struct sg_fd *nextfp;	/* NULL when last opened fd on this device */
141 	struct sg_device *parentdp;	/* owning device */
142 	wait_queue_head_t read_wait;	/* queue read until command done */
143 	rwlock_t rq_list_lock;	/* protect access to list in req_arr */
144 	int timeout;		/* defaults to SG_DEFAULT_TIMEOUT      */
145 	int timeout_user;	/* defaults to SG_DEFAULT_TIMEOUT_USER */
146 	Sg_scatter_hold reserve;	/* buffer held for this file descriptor */
147 	unsigned save_scat_len;	/* original length of trunc. scat. element */
148 	Sg_request *headrp;	/* head of request slist, NULL->empty */
149 	struct fasync_struct *async_qp;	/* used by asynchronous notification */
150 	Sg_request req_arr[SG_MAX_QUEUE];	/* used as singly-linked list */
151 	char low_dma;		/* as in parent but possibly overridden to 1 */
152 	char force_packid;	/* 1 -> pack_id input to read(), 0 -> ignored */
153 	volatile char closed;	/* 1 -> fd closed but request(s) outstanding */
154 	char cmd_q;		/* 1 -> allow command queuing, 0 -> don't */
155 	char next_cmd_len;	/* 0 -> automatic (def), >0 -> use on next write() */
156 	char keep_orphan;	/* 0 -> drop orphan (def), 1 -> keep for read() */
157 	char mmap_called;	/* 0 -> mmap() never called on this fd */
158 } Sg_fd;
159 
160 typedef struct sg_device { /* holds the state of each scsi generic device */
161 	struct scsi_device *device;
162 	wait_queue_head_t o_excl_wait;	/* queue open() when O_EXCL in use */
163 	int sg_tablesize;	/* adapter's max scatter-gather table size */
164 	Sg_fd *headfp;		/* first open fd belonging to this device */
165 	volatile char detached;	/* 0->attached, 1->detached pending removal */
166 	volatile char exclude;	/* opened for exclusive access */
167 	char sgdebug;		/* 0->off, 1->sense, 9->dump dev, 10-> all devs */
168 	struct gendisk *disk;
169 	struct cdev * cdev;	/* char_dev [sysfs: /sys/cdev/major/sg<n>] */
170 } Sg_device;
171 
172 static int sg_fasync(int fd, struct file *filp, int mode);
173 /* tasklet or soft irq callback */
174 static void sg_cmd_done(void *data, char *sense, int result, int resid);
175 static int sg_start_req(Sg_request * srp);
176 static void sg_finish_rem_req(Sg_request * srp);
177 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
178 static int sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp,
179 			 int tablesize);
180 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
181 			   Sg_request * srp);
182 static ssize_t sg_new_write(Sg_fd * sfp, const char __user *buf, size_t count,
183 			    int blocking, int read_only, Sg_request ** o_srp);
184 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
185 			   unsigned char *cmnd, int timeout, int blocking);
186 static int sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind,
187 		      int wr_xf, int *countp, unsigned char __user **up);
188 static int sg_write_xfer(Sg_request * srp);
189 static int sg_read_xfer(Sg_request * srp);
190 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
191 static void sg_remove_scat(Sg_scatter_hold * schp);
192 static void sg_build_reserve(Sg_fd * sfp, int req_size);
193 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
194 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
195 static struct page *sg_page_malloc(int rqSz, int lowDma, int *retSzp);
196 static void sg_page_free(struct page *page, int size);
197 static Sg_fd *sg_add_sfp(Sg_device * sdp, int dev);
198 static int sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
199 static void __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
200 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
201 static Sg_request *sg_add_request(Sg_fd * sfp);
202 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
203 static int sg_res_in_use(Sg_fd * sfp);
204 static int sg_allow_access(unsigned char opcode, char dev_type);
205 static int sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len);
206 static Sg_device *sg_get_dev(int dev);
207 #ifdef CONFIG_SCSI_PROC_FS
208 static int sg_last_dev(void);
209 #endif
210 
211 static Sg_device **sg_dev_arr = NULL;
212 static int sg_dev_max;
213 static int sg_nr_dev;
214 
215 #define SZ_SG_HEADER sizeof(struct sg_header)
216 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
217 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
218 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
219 
220 static int
221 sg_open(struct inode *inode, struct file *filp)
222 {
223 	int dev = iminor(inode);
224 	int flags = filp->f_flags;
225 	struct request_queue *q;
226 	Sg_device *sdp;
227 	Sg_fd *sfp;
228 	int res;
229 	int retval;
230 
231 	nonseekable_open(inode, filp);
232 	SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
233 	sdp = sg_get_dev(dev);
234 	if ((!sdp) || (!sdp->device))
235 		return -ENXIO;
236 	if (sdp->detached)
237 		return -ENODEV;
238 
239 	/* This driver's module count bumped by fops_get in <linux/fs.h> */
240 	/* Prevent the device driver from vanishing while we sleep */
241 	retval = scsi_device_get(sdp->device);
242 	if (retval)
243 		return retval;
244 
245 	if (!((flags & O_NONBLOCK) ||
246 	      scsi_block_when_processing_errors(sdp->device))) {
247 		retval = -ENXIO;
248 		/* we are in error recovery for this device */
249 		goto error_out;
250 	}
251 
252 	if (flags & O_EXCL) {
253 		if (O_RDONLY == (flags & O_ACCMODE)) {
254 			retval = -EPERM; /* Can't lock it with read only access */
255 			goto error_out;
256 		}
257 		if (sdp->headfp && (flags & O_NONBLOCK)) {
258 			retval = -EBUSY;
259 			goto error_out;
260 		}
261 		res = 0;
262 		__wait_event_interruptible(sdp->o_excl_wait,
263 			((sdp->headfp || sdp->exclude) ? 0 : (sdp->exclude = 1)), res);
264 		if (res) {
265 			retval = res;	/* -ERESTARTSYS because signal hit process */
266 			goto error_out;
267 		}
268 	} else if (sdp->exclude) {	/* some other fd has an exclusive lock on dev */
269 		if (flags & O_NONBLOCK) {
270 			retval = -EBUSY;
271 			goto error_out;
272 		}
273 		res = 0;
274 		__wait_event_interruptible(sdp->o_excl_wait, (!sdp->exclude),
275 					   res);
276 		if (res) {
277 			retval = res;	/* -ERESTARTSYS because signal hit process */
278 			goto error_out;
279 		}
280 	}
281 	if (sdp->detached) {
282 		retval = -ENODEV;
283 		goto error_out;
284 	}
285 	if (!sdp->headfp) {	/* no existing opens on this device */
286 		sdp->sgdebug = 0;
287 		q = sdp->device->request_queue;
288 		sdp->sg_tablesize = min(q->max_hw_segments,
289 					q->max_phys_segments);
290 	}
291 	if ((sfp = sg_add_sfp(sdp, dev)))
292 		filp->private_data = sfp;
293 	else {
294 		if (flags & O_EXCL)
295 			sdp->exclude = 0;	/* undo if error */
296 		retval = -ENOMEM;
297 		goto error_out;
298 	}
299 	return 0;
300 
301       error_out:
302 	scsi_device_put(sdp->device);
303 	return retval;
304 }
305 
306 /* Following function was formerly called 'sg_close' */
307 static int
308 sg_release(struct inode *inode, struct file *filp)
309 {
310 	Sg_device *sdp;
311 	Sg_fd *sfp;
312 
313 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
314 		return -ENXIO;
315 	SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
316 	sg_fasync(-1, filp, 0);	/* remove filp from async notification list */
317 	if (0 == sg_remove_sfp(sdp, sfp)) {	/* Returns 1 when sdp gone */
318 		if (!sdp->detached) {
319 			scsi_device_put(sdp->device);
320 		}
321 		sdp->exclude = 0;
322 		wake_up_interruptible(&sdp->o_excl_wait);
323 	}
324 	return 0;
325 }
326 
327 static ssize_t
328 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
329 {
330 	Sg_device *sdp;
331 	Sg_fd *sfp;
332 	Sg_request *srp;
333 	int req_pack_id = -1;
334 	sg_io_hdr_t *hp;
335 	struct sg_header *old_hdr = NULL;
336 	int retval = 0;
337 
338 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
339 		return -ENXIO;
340 	SCSI_LOG_TIMEOUT(3, printk("sg_read: %s, count=%d\n",
341 				   sdp->disk->disk_name, (int) count));
342 
343 	if (!access_ok(VERIFY_WRITE, buf, count))
344 		return -EFAULT;
345 	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
346 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
347 		if (!old_hdr)
348 			return -ENOMEM;
349 		if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
350 			retval = -EFAULT;
351 			goto free_old_hdr;
352 		}
353 		if (old_hdr->reply_len < 0) {
354 			if (count >= SZ_SG_IO_HDR) {
355 				sg_io_hdr_t *new_hdr;
356 				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
357 				if (!new_hdr) {
358 					retval = -ENOMEM;
359 					goto free_old_hdr;
360 				}
361 				retval =__copy_from_user
362 				    (new_hdr, buf, SZ_SG_IO_HDR);
363 				req_pack_id = new_hdr->pack_id;
364 				kfree(new_hdr);
365 				if (retval) {
366 					retval = -EFAULT;
367 					goto free_old_hdr;
368 				}
369 			}
370 		} else
371 			req_pack_id = old_hdr->pack_id;
372 	}
373 	srp = sg_get_rq_mark(sfp, req_pack_id);
374 	if (!srp) {		/* now wait on packet to arrive */
375 		if (sdp->detached) {
376 			retval = -ENODEV;
377 			goto free_old_hdr;
378 		}
379 		if (filp->f_flags & O_NONBLOCK) {
380 			retval = -EAGAIN;
381 			goto free_old_hdr;
382 		}
383 		while (1) {
384 			retval = 0; /* following macro beats race condition */
385 			__wait_event_interruptible(sfp->read_wait,
386 				(sdp->detached ||
387 				(srp = sg_get_rq_mark(sfp, req_pack_id))),
388 				retval);
389 			if (sdp->detached) {
390 				retval = -ENODEV;
391 				goto free_old_hdr;
392 			}
393 			if (0 == retval)
394 				break;
395 
396 			/* -ERESTARTSYS as signal hit process */
397 			goto free_old_hdr;
398 		}
399 	}
400 	if (srp->header.interface_id != '\0') {
401 		retval = sg_new_read(sfp, buf, count, srp);
402 		goto free_old_hdr;
403 	}
404 
405 	hp = &srp->header;
406 	if (old_hdr == NULL) {
407 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
408 		if (! old_hdr) {
409 			retval = -ENOMEM;
410 			goto free_old_hdr;
411 		}
412 	}
413 	memset(old_hdr, 0, SZ_SG_HEADER);
414 	old_hdr->reply_len = (int) hp->timeout;
415 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
416 	old_hdr->pack_id = hp->pack_id;
417 	old_hdr->twelve_byte =
418 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
419 	old_hdr->target_status = hp->masked_status;
420 	old_hdr->host_status = hp->host_status;
421 	old_hdr->driver_status = hp->driver_status;
422 	if ((CHECK_CONDITION & hp->masked_status) ||
423 	    (DRIVER_SENSE & hp->driver_status))
424 		memcpy(old_hdr->sense_buffer, srp->sense_b,
425 		       sizeof (old_hdr->sense_buffer));
426 	switch (hp->host_status) {
427 	/* This setup of 'result' is for backward compatibility and is best
428 	   ignored by the user who should use target, host + driver status */
429 	case DID_OK:
430 	case DID_PASSTHROUGH:
431 	case DID_SOFT_ERROR:
432 		old_hdr->result = 0;
433 		break;
434 	case DID_NO_CONNECT:
435 	case DID_BUS_BUSY:
436 	case DID_TIME_OUT:
437 		old_hdr->result = EBUSY;
438 		break;
439 	case DID_BAD_TARGET:
440 	case DID_ABORT:
441 	case DID_PARITY:
442 	case DID_RESET:
443 	case DID_BAD_INTR:
444 		old_hdr->result = EIO;
445 		break;
446 	case DID_ERROR:
447 		old_hdr->result = (srp->sense_b[0] == 0 &&
448 				  hp->masked_status == GOOD) ? 0 : EIO;
449 		break;
450 	default:
451 		old_hdr->result = EIO;
452 		break;
453 	}
454 
455 	/* Now copy the result back to the user buffer.  */
456 	if (count >= SZ_SG_HEADER) {
457 		if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
458 			retval = -EFAULT;
459 			goto free_old_hdr;
460 		}
461 		buf += SZ_SG_HEADER;
462 		if (count > old_hdr->reply_len)
463 			count = old_hdr->reply_len;
464 		if (count > SZ_SG_HEADER) {
465 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
466 				retval = -EFAULT;
467 				goto free_old_hdr;
468 			}
469 		}
470 	} else
471 		count = (old_hdr->result == 0) ? 0 : -EIO;
472 	sg_finish_rem_req(srp);
473 	retval = count;
474 free_old_hdr:
475 	kfree(old_hdr);
476 	return retval;
477 }
478 
479 static ssize_t
480 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
481 {
482 	sg_io_hdr_t *hp = &srp->header;
483 	int err = 0;
484 	int len;
485 
486 	if (count < SZ_SG_IO_HDR) {
487 		err = -EINVAL;
488 		goto err_out;
489 	}
490 	hp->sb_len_wr = 0;
491 	if ((hp->mx_sb_len > 0) && hp->sbp) {
492 		if ((CHECK_CONDITION & hp->masked_status) ||
493 		    (DRIVER_SENSE & hp->driver_status)) {
494 			int sb_len = SCSI_SENSE_BUFFERSIZE;
495 			sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
496 			len = 8 + (int) srp->sense_b[7];	/* Additional sense length field */
497 			len = (len > sb_len) ? sb_len : len;
498 			if (copy_to_user(hp->sbp, srp->sense_b, len)) {
499 				err = -EFAULT;
500 				goto err_out;
501 			}
502 			hp->sb_len_wr = len;
503 		}
504 	}
505 	if (hp->masked_status || hp->host_status || hp->driver_status)
506 		hp->info |= SG_INFO_CHECK;
507 	if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
508 		err = -EFAULT;
509 		goto err_out;
510 	}
511 	err = sg_read_xfer(srp);
512       err_out:
513 	sg_finish_rem_req(srp);
514 	return (0 == err) ? count : err;
515 }
516 
517 static ssize_t
518 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
519 {
520 	int mxsize, cmd_size, k;
521 	int input_size, blocking;
522 	unsigned char opcode;
523 	Sg_device *sdp;
524 	Sg_fd *sfp;
525 	Sg_request *srp;
526 	struct sg_header old_hdr;
527 	sg_io_hdr_t *hp;
528 	unsigned char cmnd[MAX_COMMAND_SIZE];
529 
530 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
531 		return -ENXIO;
532 	SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n",
533 				   sdp->disk->disk_name, (int) count));
534 	if (sdp->detached)
535 		return -ENODEV;
536 	if (!((filp->f_flags & O_NONBLOCK) ||
537 	      scsi_block_when_processing_errors(sdp->device)))
538 		return -ENXIO;
539 
540 	if (!access_ok(VERIFY_READ, buf, count))
541 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
542 	if (count < SZ_SG_HEADER)
543 		return -EIO;
544 	if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
545 		return -EFAULT;
546 	blocking = !(filp->f_flags & O_NONBLOCK);
547 	if (old_hdr.reply_len < 0)
548 		return sg_new_write(sfp, buf, count, blocking, 0, NULL);
549 	if (count < (SZ_SG_HEADER + 6))
550 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
551 
552 	if (!(srp = sg_add_request(sfp))) {
553 		SCSI_LOG_TIMEOUT(1, printk("sg_write: queue full\n"));
554 		return -EDOM;
555 	}
556 	buf += SZ_SG_HEADER;
557 	__get_user(opcode, buf);
558 	if (sfp->next_cmd_len > 0) {
559 		if (sfp->next_cmd_len > MAX_COMMAND_SIZE) {
560 			SCSI_LOG_TIMEOUT(1, printk("sg_write: command length too long\n"));
561 			sfp->next_cmd_len = 0;
562 			sg_remove_request(sfp, srp);
563 			return -EIO;
564 		}
565 		cmd_size = sfp->next_cmd_len;
566 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
567 	} else {
568 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
569 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
570 			cmd_size = 12;
571 	}
572 	SCSI_LOG_TIMEOUT(4, printk(
573 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
574 /* Determine buffer size.  */
575 	input_size = count - cmd_size;
576 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
577 	mxsize -= SZ_SG_HEADER;
578 	input_size -= SZ_SG_HEADER;
579 	if (input_size < 0) {
580 		sg_remove_request(sfp, srp);
581 		return -EIO;	/* User did not pass enough bytes for this command. */
582 	}
583 	hp = &srp->header;
584 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
585 	hp->cmd_len = (unsigned char) cmd_size;
586 	hp->iovec_count = 0;
587 	hp->mx_sb_len = 0;
588 	if (input_size > 0)
589 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
590 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
591 	else
592 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
593 	hp->dxfer_len = mxsize;
594 	hp->dxferp = (char __user *)buf + cmd_size;
595 	hp->sbp = NULL;
596 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
597 	hp->flags = input_size;	/* structure abuse ... */
598 	hp->pack_id = old_hdr.pack_id;
599 	hp->usr_ptr = NULL;
600 	if (__copy_from_user(cmnd, buf, cmd_size))
601 		return -EFAULT;
602 	/*
603 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
604 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
605 	 * is a non-zero input_size, so emit a warning.
606 	 */
607 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV)
608 		if (printk_ratelimit())
609 			printk(KERN_WARNING
610 			       "sg_write: data in/out %d/%d bytes for SCSI command 0x%x--"
611 			       "guessing data in;\n" KERN_WARNING "   "
612 			       "program %s not setting count and/or reply_len properly\n",
613 			       old_hdr.reply_len - (int)SZ_SG_HEADER,
614 			       input_size, (unsigned int) cmnd[0],
615 			       current->comm);
616 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
617 	return (k < 0) ? k : count;
618 }
619 
620 static ssize_t
621 sg_new_write(Sg_fd * sfp, const char __user *buf, size_t count,
622 	     int blocking, int read_only, Sg_request ** o_srp)
623 {
624 	int k;
625 	Sg_request *srp;
626 	sg_io_hdr_t *hp;
627 	unsigned char cmnd[MAX_COMMAND_SIZE];
628 	int timeout;
629 	unsigned long ul_timeout;
630 
631 	if (count < SZ_SG_IO_HDR)
632 		return -EINVAL;
633 	if (!access_ok(VERIFY_READ, buf, count))
634 		return -EFAULT; /* protects following copy_from_user()s + get_user()s */
635 
636 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
637 	if (!(srp = sg_add_request(sfp))) {
638 		SCSI_LOG_TIMEOUT(1, printk("sg_new_write: queue full\n"));
639 		return -EDOM;
640 	}
641 	hp = &srp->header;
642 	if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
643 		sg_remove_request(sfp, srp);
644 		return -EFAULT;
645 	}
646 	if (hp->interface_id != 'S') {
647 		sg_remove_request(sfp, srp);
648 		return -ENOSYS;
649 	}
650 	if (hp->flags & SG_FLAG_MMAP_IO) {
651 		if (hp->dxfer_len > sfp->reserve.bufflen) {
652 			sg_remove_request(sfp, srp);
653 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
654 		}
655 		if (hp->flags & SG_FLAG_DIRECT_IO) {
656 			sg_remove_request(sfp, srp);
657 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
658 		}
659 		if (sg_res_in_use(sfp)) {
660 			sg_remove_request(sfp, srp);
661 			return -EBUSY;	/* reserve buffer already being used */
662 		}
663 	}
664 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
665 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
666 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
667 		sg_remove_request(sfp, srp);
668 		return -EMSGSIZE;
669 	}
670 	if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
671 		sg_remove_request(sfp, srp);
672 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
673 	}
674 	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
675 		sg_remove_request(sfp, srp);
676 		return -EFAULT;
677 	}
678 	if (read_only &&
679 	    (!sg_allow_access(cmnd[0], sfp->parentdp->device->type))) {
680 		sg_remove_request(sfp, srp);
681 		return -EPERM;
682 	}
683 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
684 	if (k < 0)
685 		return k;
686 	if (o_srp)
687 		*o_srp = srp;
688 	return count;
689 }
690 
691 static int
692 sg_common_write(Sg_fd * sfp, Sg_request * srp,
693 		unsigned char *cmnd, int timeout, int blocking)
694 {
695 	int k, data_dir;
696 	Sg_device *sdp = sfp->parentdp;
697 	sg_io_hdr_t *hp = &srp->header;
698 
699 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
700 	hp->status = 0;
701 	hp->masked_status = 0;
702 	hp->msg_status = 0;
703 	hp->info = 0;
704 	hp->host_status = 0;
705 	hp->driver_status = 0;
706 	hp->resid = 0;
707 	SCSI_LOG_TIMEOUT(4, printk("sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
708 			  (int) cmnd[0], (int) hp->cmd_len));
709 
710 	if ((k = sg_start_req(srp))) {
711 		SCSI_LOG_TIMEOUT(1, printk("sg_write: start_req err=%d\n", k));
712 		sg_finish_rem_req(srp);
713 		return k;	/* probably out of space --> ENOMEM */
714 	}
715 	if ((k = sg_write_xfer(srp))) {
716 		SCSI_LOG_TIMEOUT(1, printk("sg_write: write_xfer, bad address\n"));
717 		sg_finish_rem_req(srp);
718 		return k;
719 	}
720 	if (sdp->detached) {
721 		sg_finish_rem_req(srp);
722 		return -ENODEV;
723 	}
724 
725 	switch (hp->dxfer_direction) {
726 	case SG_DXFER_TO_FROM_DEV:
727 	case SG_DXFER_FROM_DEV:
728 		data_dir = DMA_FROM_DEVICE;
729 		break;
730 	case SG_DXFER_TO_DEV:
731 		data_dir = DMA_TO_DEVICE;
732 		break;
733 	case SG_DXFER_UNKNOWN:
734 		data_dir = DMA_BIDIRECTIONAL;
735 		break;
736 	default:
737 		data_dir = DMA_NONE;
738 		break;
739 	}
740 	hp->duration = jiffies_to_msecs(jiffies);
741 /* Now send everything of to mid-level. The next time we hear about this
742    packet is when sg_cmd_done() is called (i.e. a callback). */
743 	if (scsi_execute_async(sdp->device, cmnd, hp->cmd_len, data_dir, srp->data.buffer,
744 				hp->dxfer_len, srp->data.k_use_sg, timeout,
745 				SG_DEFAULT_RETRIES, srp, sg_cmd_done,
746 				GFP_ATOMIC)) {
747 		SCSI_LOG_TIMEOUT(1, printk("sg_write: scsi_execute_async failed\n"));
748 		/*
749 		 * most likely out of mem, but could also be a bad map
750 		 */
751 		sg_finish_rem_req(srp);
752 		return -ENOMEM;
753 	} else
754 		return 0;
755 }
756 
757 static int
758 sg_srp_done(Sg_request *srp, Sg_fd *sfp)
759 {
760 	unsigned long iflags;
761 	int done;
762 
763 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
764 	done = srp->done;
765 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
766 	return done;
767 }
768 
769 static int
770 sg_ioctl(struct inode *inode, struct file *filp,
771 	 unsigned int cmd_in, unsigned long arg)
772 {
773 	void __user *p = (void __user *)arg;
774 	int __user *ip = p;
775 	int result, val, read_only;
776 	Sg_device *sdp;
777 	Sg_fd *sfp;
778 	Sg_request *srp;
779 	unsigned long iflags;
780 
781 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
782 		return -ENXIO;
783 	SCSI_LOG_TIMEOUT(3, printk("sg_ioctl: %s, cmd=0x%x\n",
784 				   sdp->disk->disk_name, (int) cmd_in));
785 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
786 
787 	switch (cmd_in) {
788 	case SG_IO:
789 		{
790 			int blocking = 1;	/* ignore O_NONBLOCK flag */
791 
792 			if (sdp->detached)
793 				return -ENODEV;
794 			if (!scsi_block_when_processing_errors(sdp->device))
795 				return -ENXIO;
796 			if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
797 				return -EFAULT;
798 			result =
799 			    sg_new_write(sfp, p, SZ_SG_IO_HDR,
800 					 blocking, read_only, &srp);
801 			if (result < 0)
802 				return result;
803 			srp->sg_io_owned = 1;
804 			while (1) {
805 				result = 0;	/* following macro to beat race condition */
806 				__wait_event_interruptible(sfp->read_wait,
807 					(sdp->detached || sfp->closed || sg_srp_done(srp, sfp)),
808 							   result);
809 				if (sdp->detached)
810 					return -ENODEV;
811 				if (sfp->closed)
812 					return 0;	/* request packet dropped already */
813 				if (0 == result)
814 					break;
815 				srp->orphan = 1;
816 				return result;	/* -ERESTARTSYS because signal hit process */
817 			}
818 			write_lock_irqsave(&sfp->rq_list_lock, iflags);
819 			srp->done = 2;
820 			write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
821 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
822 			return (result < 0) ? result : 0;
823 		}
824 	case SG_SET_TIMEOUT:
825 		result = get_user(val, ip);
826 		if (result)
827 			return result;
828 		if (val < 0)
829 			return -EIO;
830 		if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
831 		    val = MULDIV (INT_MAX, USER_HZ, HZ);
832 		sfp->timeout_user = val;
833 		sfp->timeout = MULDIV (val, HZ, USER_HZ);
834 
835 		return 0;
836 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
837 				/* strange ..., for backward compatibility */
838 		return sfp->timeout_user;
839 	case SG_SET_FORCE_LOW_DMA:
840 		result = get_user(val, ip);
841 		if (result)
842 			return result;
843 		if (val) {
844 			sfp->low_dma = 1;
845 			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
846 				val = (int) sfp->reserve.bufflen;
847 				sg_remove_scat(&sfp->reserve);
848 				sg_build_reserve(sfp, val);
849 			}
850 		} else {
851 			if (sdp->detached)
852 				return -ENODEV;
853 			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
854 		}
855 		return 0;
856 	case SG_GET_LOW_DMA:
857 		return put_user((int) sfp->low_dma, ip);
858 	case SG_GET_SCSI_ID:
859 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
860 			return -EFAULT;
861 		else {
862 			sg_scsi_id_t __user *sg_idp = p;
863 
864 			if (sdp->detached)
865 				return -ENODEV;
866 			__put_user((int) sdp->device->host->host_no,
867 				   &sg_idp->host_no);
868 			__put_user((int) sdp->device->channel,
869 				   &sg_idp->channel);
870 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
871 			__put_user((int) sdp->device->lun, &sg_idp->lun);
872 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
873 			__put_user((short) sdp->device->host->cmd_per_lun,
874 				   &sg_idp->h_cmd_per_lun);
875 			__put_user((short) sdp->device->queue_depth,
876 				   &sg_idp->d_queue_depth);
877 			__put_user(0, &sg_idp->unused[0]);
878 			__put_user(0, &sg_idp->unused[1]);
879 			return 0;
880 		}
881 	case SG_SET_FORCE_PACK_ID:
882 		result = get_user(val, ip);
883 		if (result)
884 			return result;
885 		sfp->force_packid = val ? 1 : 0;
886 		return 0;
887 	case SG_GET_PACK_ID:
888 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
889 			return -EFAULT;
890 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
891 		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
892 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
893 				read_unlock_irqrestore(&sfp->rq_list_lock,
894 						       iflags);
895 				__put_user(srp->header.pack_id, ip);
896 				return 0;
897 			}
898 		}
899 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
900 		__put_user(-1, ip);
901 		return 0;
902 	case SG_GET_NUM_WAITING:
903 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
904 		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
905 			if ((1 == srp->done) && (!srp->sg_io_owned))
906 				++val;
907 		}
908 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
909 		return put_user(val, ip);
910 	case SG_GET_SG_TABLESIZE:
911 		return put_user(sdp->sg_tablesize, ip);
912 	case SG_SET_RESERVED_SIZE:
913 		result = get_user(val, ip);
914 		if (result)
915 			return result;
916                 if (val < 0)
917                         return -EINVAL;
918 		if (val != sfp->reserve.bufflen) {
919 			if (sg_res_in_use(sfp) || sfp->mmap_called)
920 				return -EBUSY;
921 			sg_remove_scat(&sfp->reserve);
922 			sg_build_reserve(sfp, val);
923 		}
924 		return 0;
925 	case SG_GET_RESERVED_SIZE:
926 		val = (int) sfp->reserve.bufflen;
927 		return put_user(val, ip);
928 	case SG_SET_COMMAND_Q:
929 		result = get_user(val, ip);
930 		if (result)
931 			return result;
932 		sfp->cmd_q = val ? 1 : 0;
933 		return 0;
934 	case SG_GET_COMMAND_Q:
935 		return put_user((int) sfp->cmd_q, ip);
936 	case SG_SET_KEEP_ORPHAN:
937 		result = get_user(val, ip);
938 		if (result)
939 			return result;
940 		sfp->keep_orphan = val;
941 		return 0;
942 	case SG_GET_KEEP_ORPHAN:
943 		return put_user((int) sfp->keep_orphan, ip);
944 	case SG_NEXT_CMD_LEN:
945 		result = get_user(val, ip);
946 		if (result)
947 			return result;
948 		sfp->next_cmd_len = (val > 0) ? val : 0;
949 		return 0;
950 	case SG_GET_VERSION_NUM:
951 		return put_user(sg_version_num, ip);
952 	case SG_GET_ACCESS_COUNT:
953 		/* faked - we don't have a real access count anymore */
954 		val = (sdp->device ? 1 : 0);
955 		return put_user(val, ip);
956 	case SG_GET_REQUEST_TABLE:
957 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
958 			return -EFAULT;
959 		else {
960 			sg_req_info_t *rinfo;
961 			unsigned int ms;
962 
963 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
964 								GFP_KERNEL);
965 			if (!rinfo)
966 				return -ENOMEM;
967 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
968 			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
969 			     ++val, srp = srp ? srp->nextrp : srp) {
970 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
971 				if (srp) {
972 					rinfo[val].req_state = srp->done + 1;
973 					rinfo[val].problem =
974 					    srp->header.masked_status &
975 					    srp->header.host_status &
976 					    srp->header.driver_status;
977 					if (srp->done)
978 						rinfo[val].duration =
979 							srp->header.duration;
980 					else {
981 						ms = jiffies_to_msecs(jiffies);
982 						rinfo[val].duration =
983 						    (ms > srp->header.duration) ?
984 						    (ms - srp->header.duration) : 0;
985 					}
986 					rinfo[val].orphan = srp->orphan;
987 					rinfo[val].sg_io_owned =
988 							srp->sg_io_owned;
989 					rinfo[val].pack_id =
990 							srp->header.pack_id;
991 					rinfo[val].usr_ptr =
992 							srp->header.usr_ptr;
993 				}
994 			}
995 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
996 			result = __copy_to_user(p, rinfo,
997 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
998 			result = result ? -EFAULT : 0;
999 			kfree(rinfo);
1000 			return result;
1001 		}
1002 	case SG_EMULATED_HOST:
1003 		if (sdp->detached)
1004 			return -ENODEV;
1005 		return put_user(sdp->device->host->hostt->emulated, ip);
1006 	case SG_SCSI_RESET:
1007 		if (sdp->detached)
1008 			return -ENODEV;
1009 		if (filp->f_flags & O_NONBLOCK) {
1010 			if (scsi_host_in_recovery(sdp->device->host))
1011 				return -EBUSY;
1012 		} else if (!scsi_block_when_processing_errors(sdp->device))
1013 			return -EBUSY;
1014 		result = get_user(val, ip);
1015 		if (result)
1016 			return result;
1017 		if (SG_SCSI_RESET_NOTHING == val)
1018 			return 0;
1019 		switch (val) {
1020 		case SG_SCSI_RESET_DEVICE:
1021 			val = SCSI_TRY_RESET_DEVICE;
1022 			break;
1023 		case SG_SCSI_RESET_BUS:
1024 			val = SCSI_TRY_RESET_BUS;
1025 			break;
1026 		case SG_SCSI_RESET_HOST:
1027 			val = SCSI_TRY_RESET_HOST;
1028 			break;
1029 		default:
1030 			return -EINVAL;
1031 		}
1032 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1033 			return -EACCES;
1034 		return (scsi_reset_provider(sdp->device, val) ==
1035 			SUCCESS) ? 0 : -EIO;
1036 	case SCSI_IOCTL_SEND_COMMAND:
1037 		if (sdp->detached)
1038 			return -ENODEV;
1039 		if (read_only) {
1040 			unsigned char opcode = WRITE_6;
1041 			Scsi_Ioctl_Command __user *siocp = p;
1042 
1043 			if (copy_from_user(&opcode, siocp->data, 1))
1044 				return -EFAULT;
1045 			if (!sg_allow_access(opcode, sdp->device->type))
1046 				return -EPERM;
1047 		}
1048 		return sg_scsi_ioctl(filp, sdp->device->request_queue, NULL, p);
1049 	case SG_SET_DEBUG:
1050 		result = get_user(val, ip);
1051 		if (result)
1052 			return result;
1053 		sdp->sgdebug = (char) val;
1054 		return 0;
1055 	case SCSI_IOCTL_GET_IDLUN:
1056 	case SCSI_IOCTL_GET_BUS_NUMBER:
1057 	case SCSI_IOCTL_PROBE_HOST:
1058 	case SG_GET_TRANSFORM:
1059 		if (sdp->detached)
1060 			return -ENODEV;
1061 		return scsi_ioctl(sdp->device, cmd_in, p);
1062 	default:
1063 		if (read_only)
1064 			return -EPERM;	/* don't know so take safe approach */
1065 		return scsi_ioctl(sdp->device, cmd_in, p);
1066 	}
1067 }
1068 
1069 #ifdef CONFIG_COMPAT
1070 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1071 {
1072 	Sg_device *sdp;
1073 	Sg_fd *sfp;
1074 	struct scsi_device *sdev;
1075 
1076 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1077 		return -ENXIO;
1078 
1079 	sdev = sdp->device;
1080 	if (sdev->host->hostt->compat_ioctl) {
1081 		int ret;
1082 
1083 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1084 
1085 		return ret;
1086 	}
1087 
1088 	return -ENOIOCTLCMD;
1089 }
1090 #endif
1091 
1092 static unsigned int
1093 sg_poll(struct file *filp, poll_table * wait)
1094 {
1095 	unsigned int res = 0;
1096 	Sg_device *sdp;
1097 	Sg_fd *sfp;
1098 	Sg_request *srp;
1099 	int count = 0;
1100 	unsigned long iflags;
1101 
1102 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))
1103 	    || sfp->closed)
1104 		return POLLERR;
1105 	poll_wait(filp, &sfp->read_wait, wait);
1106 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1107 	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1108 		/* if any read waiting, flag it */
1109 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1110 			res = POLLIN | POLLRDNORM;
1111 		++count;
1112 	}
1113 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1114 
1115 	if (sdp->detached)
1116 		res |= POLLHUP;
1117 	else if (!sfp->cmd_q) {
1118 		if (0 == count)
1119 			res |= POLLOUT | POLLWRNORM;
1120 	} else if (count < SG_MAX_QUEUE)
1121 		res |= POLLOUT | POLLWRNORM;
1122 	SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
1123 				   sdp->disk->disk_name, (int) res));
1124 	return res;
1125 }
1126 
1127 static int
1128 sg_fasync(int fd, struct file *filp, int mode)
1129 {
1130 	int retval;
1131 	Sg_device *sdp;
1132 	Sg_fd *sfp;
1133 
1134 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1135 		return -ENXIO;
1136 	SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
1137 				   sdp->disk->disk_name, mode));
1138 
1139 	retval = fasync_helper(fd, filp, mode, &sfp->async_qp);
1140 	return (retval < 0) ? retval : 0;
1141 }
1142 
1143 static struct page *
1144 sg_vma_nopage(struct vm_area_struct *vma, unsigned long addr, int *type)
1145 {
1146 	Sg_fd *sfp;
1147 	struct page *page = NOPAGE_SIGBUS;
1148 	unsigned long offset, len, sa;
1149 	Sg_scatter_hold *rsv_schp;
1150 	struct scatterlist *sg;
1151 	int k;
1152 
1153 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1154 		return page;
1155 	rsv_schp = &sfp->reserve;
1156 	offset = addr - vma->vm_start;
1157 	if (offset >= rsv_schp->bufflen)
1158 		return page;
1159 	SCSI_LOG_TIMEOUT(3, printk("sg_vma_nopage: offset=%lu, scatg=%d\n",
1160 				   offset, rsv_schp->k_use_sg));
1161 	sg = rsv_schp->buffer;
1162 	sa = vma->vm_start;
1163 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
1164 	     ++k, ++sg) {
1165 		len = vma->vm_end - sa;
1166 		len = (len < sg->length) ? len : sg->length;
1167 		if (offset < len) {
1168 			page = sg->page;
1169 			get_page(page);	/* increment page count */
1170 			break;
1171 		}
1172 		sa += len;
1173 		offset -= len;
1174 	}
1175 
1176 	if (type)
1177 		*type = VM_FAULT_MINOR;
1178 	return page;
1179 }
1180 
1181 static struct vm_operations_struct sg_mmap_vm_ops = {
1182 	.nopage = sg_vma_nopage,
1183 };
1184 
1185 static int
1186 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1187 {
1188 	Sg_fd *sfp;
1189 	unsigned long req_sz, len, sa;
1190 	Sg_scatter_hold *rsv_schp;
1191 	int k;
1192 	struct scatterlist *sg;
1193 
1194 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1195 		return -ENXIO;
1196 	req_sz = vma->vm_end - vma->vm_start;
1197 	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
1198 				   (void *) vma->vm_start, (int) req_sz));
1199 	if (vma->vm_pgoff)
1200 		return -EINVAL;	/* want no offset */
1201 	rsv_schp = &sfp->reserve;
1202 	if (req_sz > rsv_schp->bufflen)
1203 		return -ENOMEM;	/* cannot map more than reserved buffer */
1204 
1205 	sa = vma->vm_start;
1206 	sg = rsv_schp->buffer;
1207 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
1208 	     ++k, ++sg) {
1209 		len = vma->vm_end - sa;
1210 		len = (len < sg->length) ? len : sg->length;
1211 		sa += len;
1212 	}
1213 
1214 	sfp->mmap_called = 1;
1215 	vma->vm_flags |= VM_RESERVED;
1216 	vma->vm_private_data = sfp;
1217 	vma->vm_ops = &sg_mmap_vm_ops;
1218 	return 0;
1219 }
1220 
1221 /* This function is a "bottom half" handler that is called by the
1222  * mid level when a command is completed (or has failed). */
1223 static void
1224 sg_cmd_done(void *data, char *sense, int result, int resid)
1225 {
1226 	Sg_request *srp = data;
1227 	Sg_device *sdp = NULL;
1228 	Sg_fd *sfp;
1229 	unsigned long iflags;
1230 	unsigned int ms;
1231 
1232 	if (NULL == srp) {
1233 		printk(KERN_ERR "sg_cmd_done: NULL request\n");
1234 		return;
1235 	}
1236 	sfp = srp->parentfp;
1237 	if (sfp)
1238 		sdp = sfp->parentdp;
1239 	if ((NULL == sdp) || sdp->detached) {
1240 		printk(KERN_INFO "sg_cmd_done: device detached\n");
1241 		return;
1242 	}
1243 
1244 
1245 	SCSI_LOG_TIMEOUT(4, printk("sg_cmd_done: %s, pack_id=%d, res=0x%x\n",
1246 		sdp->disk->disk_name, srp->header.pack_id, result));
1247 	srp->header.resid = resid;
1248 	ms = jiffies_to_msecs(jiffies);
1249 	srp->header.duration = (ms > srp->header.duration) ?
1250 				(ms - srp->header.duration) : 0;
1251 	if (0 != result) {
1252 		struct scsi_sense_hdr sshdr;
1253 
1254 		memcpy(srp->sense_b, sense, sizeof (srp->sense_b));
1255 		srp->header.status = 0xff & result;
1256 		srp->header.masked_status = status_byte(result);
1257 		srp->header.msg_status = msg_byte(result);
1258 		srp->header.host_status = host_byte(result);
1259 		srp->header.driver_status = driver_byte(result);
1260 		if ((sdp->sgdebug > 0) &&
1261 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1262 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1263 			__scsi_print_sense("sg_cmd_done", sense,
1264 					   SCSI_SENSE_BUFFERSIZE);
1265 
1266 		/* Following if statement is a patch supplied by Eric Youngdale */
1267 		if (driver_byte(result) != 0
1268 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1269 		    && !scsi_sense_is_deferred(&sshdr)
1270 		    && sshdr.sense_key == UNIT_ATTENTION
1271 		    && sdp->device->removable) {
1272 			/* Detected possible disc change. Set the bit - this */
1273 			/* may be used if there are filesystems using this device */
1274 			sdp->device->changed = 1;
1275 		}
1276 	}
1277 	/* Rely on write phase to clean out srp status values, so no "else" */
1278 
1279 	if (sfp->closed) {	/* whoops this fd already released, cleanup */
1280 		SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, freeing ...\n"));
1281 		sg_finish_rem_req(srp);
1282 		srp = NULL;
1283 		if (NULL == sfp->headrp) {
1284 			SCSI_LOG_TIMEOUT(1, printk("sg...bh: already closed, final cleanup\n"));
1285 			if (0 == sg_remove_sfp(sdp, sfp)) {	/* device still present */
1286 				scsi_device_put(sdp->device);
1287 			}
1288 			sfp = NULL;
1289 		}
1290 	} else if (srp && srp->orphan) {
1291 		if (sfp->keep_orphan)
1292 			srp->sg_io_owned = 0;
1293 		else {
1294 			sg_finish_rem_req(srp);
1295 			srp = NULL;
1296 		}
1297 	}
1298 	if (sfp && srp) {
1299 		/* Now wake up any sg_read() that is waiting for this packet. */
1300 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1301 		write_lock_irqsave(&sfp->rq_list_lock, iflags);
1302 		srp->done = 1;
1303 		wake_up_interruptible(&sfp->read_wait);
1304 		write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1305 	}
1306 }
1307 
1308 static struct file_operations sg_fops = {
1309 	.owner = THIS_MODULE,
1310 	.read = sg_read,
1311 	.write = sg_write,
1312 	.poll = sg_poll,
1313 	.ioctl = sg_ioctl,
1314 #ifdef CONFIG_COMPAT
1315 	.compat_ioctl = sg_compat_ioctl,
1316 #endif
1317 	.open = sg_open,
1318 	.mmap = sg_mmap,
1319 	.release = sg_release,
1320 	.fasync = sg_fasync,
1321 };
1322 
1323 static struct class *sg_sysfs_class;
1324 
1325 static int sg_sysfs_valid = 0;
1326 
1327 static int sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1328 {
1329 	struct request_queue *q = scsidp->request_queue;
1330 	Sg_device *sdp;
1331 	unsigned long iflags;
1332 	void *old_sg_dev_arr = NULL;
1333 	int k, error;
1334 
1335 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1336 	if (!sdp) {
1337 		printk(KERN_WARNING "kmalloc Sg_device failure\n");
1338 		return -ENOMEM;
1339 	}
1340 
1341 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
1342 	if (unlikely(sg_nr_dev >= sg_dev_max)) {	/* try to resize */
1343 		Sg_device **tmp_da;
1344 		int tmp_dev_max = sg_nr_dev + SG_DEV_ARR_LUMP;
1345 		write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1346 
1347 		tmp_da = kzalloc(tmp_dev_max * sizeof(Sg_device *), GFP_KERNEL);
1348 		if (unlikely(!tmp_da))
1349 			goto expand_failed;
1350 
1351 		write_lock_irqsave(&sg_dev_arr_lock, iflags);
1352 		memcpy(tmp_da, sg_dev_arr, sg_dev_max * sizeof(Sg_device *));
1353 		old_sg_dev_arr = sg_dev_arr;
1354 		sg_dev_arr = tmp_da;
1355 		sg_dev_max = tmp_dev_max;
1356 	}
1357 
1358 	for (k = 0; k < sg_dev_max; k++)
1359 		if (!sg_dev_arr[k])
1360 			break;
1361 	if (unlikely(k >= SG_MAX_DEVS))
1362 		goto overflow;
1363 
1364 	SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
1365 	sprintf(disk->disk_name, "sg%d", k);
1366 	disk->first_minor = k;
1367 	sdp->disk = disk;
1368 	sdp->device = scsidp;
1369 	init_waitqueue_head(&sdp->o_excl_wait);
1370 	sdp->sg_tablesize = min(q->max_hw_segments, q->max_phys_segments);
1371 
1372 	sg_nr_dev++;
1373 	sg_dev_arr[k] = sdp;
1374 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1375 	error = k;
1376 
1377  out:
1378 	if (error < 0)
1379 		kfree(sdp);
1380 	kfree(old_sg_dev_arr);
1381 	return error;
1382 
1383  expand_failed:
1384 	printk(KERN_WARNING "sg_alloc: device array cannot be resized\n");
1385 	error = -ENOMEM;
1386 	goto out;
1387 
1388  overflow:
1389 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1390 	sdev_printk(KERN_WARNING, scsidp,
1391 		    "Unable to attach sg device type=%d, minor "
1392 		    "number exceeds %d\n", scsidp->type, SG_MAX_DEVS - 1);
1393 	error = -ENODEV;
1394 	goto out;
1395 }
1396 
1397 static int
1398 sg_add(struct class_device *cl_dev, struct class_interface *cl_intf)
1399 {
1400 	struct scsi_device *scsidp = to_scsi_device(cl_dev->dev);
1401 	struct gendisk *disk;
1402 	Sg_device *sdp = NULL;
1403 	struct cdev * cdev = NULL;
1404 	int error, k;
1405 
1406 	disk = alloc_disk(1);
1407 	if (!disk) {
1408 		printk(KERN_WARNING "alloc_disk failed\n");
1409 		return -ENOMEM;
1410 	}
1411 	disk->major = SCSI_GENERIC_MAJOR;
1412 
1413 	error = -ENOMEM;
1414 	cdev = cdev_alloc();
1415 	if (!cdev) {
1416 		printk(KERN_WARNING "cdev_alloc failed\n");
1417 		goto out;
1418 	}
1419 	cdev->owner = THIS_MODULE;
1420 	cdev->ops = &sg_fops;
1421 
1422 	error = sg_alloc(disk, scsidp);
1423 	if (error < 0) {
1424 		printk(KERN_WARNING "sg_alloc failed\n");
1425 		goto out;
1426 	}
1427 	k = error;
1428 	sdp = sg_dev_arr[k];
1429 
1430 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, k), 1);
1431 	if (error)
1432 		goto out;
1433 
1434 	sdp->cdev = cdev;
1435 	if (sg_sysfs_valid) {
1436 		struct class_device * sg_class_member;
1437 
1438 		sg_class_member = class_device_create(sg_sysfs_class, NULL,
1439 				MKDEV(SCSI_GENERIC_MAJOR, k),
1440 				cl_dev->dev, "%s",
1441 				disk->disk_name);
1442 		if (IS_ERR(sg_class_member))
1443 			printk(KERN_WARNING "sg_add: "
1444 				"class_device_create failed\n");
1445 		class_set_devdata(sg_class_member, sdp);
1446 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1447 					  &sg_class_member->kobj, "generic");
1448 		if (error)
1449 			printk(KERN_ERR "sg_add: unable to make symlink "
1450 					"'generic' back to sg%d\n", k);
1451 	} else
1452 		printk(KERN_WARNING "sg_add: sg_sys INvalid\n");
1453 
1454 	sdev_printk(KERN_NOTICE, scsidp,
1455 		    "Attached scsi generic sg%d type %d\n", k,scsidp->type);
1456 
1457 	return 0;
1458 
1459 out:
1460 	put_disk(disk);
1461 	if (cdev)
1462 		cdev_del(cdev);
1463 	return error;
1464 }
1465 
1466 static void
1467 sg_remove(struct class_device *cl_dev, struct class_interface *cl_intf)
1468 {
1469 	struct scsi_device *scsidp = to_scsi_device(cl_dev->dev);
1470 	Sg_device *sdp = NULL;
1471 	unsigned long iflags;
1472 	Sg_fd *sfp;
1473 	Sg_fd *tsfp;
1474 	Sg_request *srp;
1475 	Sg_request *tsrp;
1476 	int k, delay;
1477 
1478 	if (NULL == sg_dev_arr)
1479 		return;
1480 	delay = 0;
1481 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
1482 	for (k = 0; k < sg_dev_max; k++) {
1483 		sdp = sg_dev_arr[k];
1484 		if ((NULL == sdp) || (sdp->device != scsidp))
1485 			continue;	/* dirty but lowers nesting */
1486 		if (sdp->headfp) {
1487 			sdp->detached = 1;
1488 			for (sfp = sdp->headfp; sfp; sfp = tsfp) {
1489 				tsfp = sfp->nextfp;
1490 				for (srp = sfp->headrp; srp; srp = tsrp) {
1491 					tsrp = srp->nextrp;
1492 					if (sfp->closed || (0 == sg_srp_done(srp, sfp)))
1493 						sg_finish_rem_req(srp);
1494 				}
1495 				if (sfp->closed) {
1496 					scsi_device_put(sdp->device);
1497 					__sg_remove_sfp(sdp, sfp);
1498 				} else {
1499 					delay = 1;
1500 					wake_up_interruptible(&sfp->read_wait);
1501 					kill_fasync(&sfp->async_qp, SIGPOLL,
1502 						    POLL_HUP);
1503 				}
1504 			}
1505 			SCSI_LOG_TIMEOUT(3, printk("sg_detach: dev=%d, dirty\n", k));
1506 			if (NULL == sdp->headfp) {
1507 				sg_dev_arr[k] = NULL;
1508 			}
1509 		} else {	/* nothing active, simple case */
1510 			SCSI_LOG_TIMEOUT(3, printk("sg_detach: dev=%d\n", k));
1511 			sg_dev_arr[k] = NULL;
1512 		}
1513 		sg_nr_dev--;
1514 		break;
1515 	}
1516 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1517 
1518 	if (sdp) {
1519 		sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1520 		class_device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, k));
1521 		cdev_del(sdp->cdev);
1522 		sdp->cdev = NULL;
1523 		put_disk(sdp->disk);
1524 		sdp->disk = NULL;
1525 		if (NULL == sdp->headfp)
1526 			kfree((char *) sdp);
1527 	}
1528 
1529 	if (delay)
1530 		msleep(10);	/* dirty detach so delay device destruction */
1531 }
1532 
1533 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
1534  * of sysfs parameters (which module_param doesn't yet support).
1535  * Sysfs parameters defined explicitly below.
1536  */
1537 module_param_named(def_reserved_size, def_reserved_size, int, S_IRUGO);
1538 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1539 
1540 MODULE_AUTHOR("Douglas Gilbert");
1541 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1542 MODULE_LICENSE("GPL");
1543 MODULE_VERSION(SG_VERSION_STR);
1544 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1545 
1546 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1547 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1548 
1549 static int __init
1550 init_sg(void)
1551 {
1552 	int rc;
1553 
1554 	if (def_reserved_size >= 0)
1555 		sg_big_buff = def_reserved_size;
1556 
1557 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1558 				    SG_MAX_DEVS, "sg");
1559 	if (rc)
1560 		return rc;
1561         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1562         if ( IS_ERR(sg_sysfs_class) ) {
1563 		rc = PTR_ERR(sg_sysfs_class);
1564 		goto err_out;
1565         }
1566 	sg_sysfs_valid = 1;
1567 	rc = scsi_register_interface(&sg_interface);
1568 	if (0 == rc) {
1569 #ifdef CONFIG_SCSI_PROC_FS
1570 		sg_proc_init();
1571 #endif				/* CONFIG_SCSI_PROC_FS */
1572 		return 0;
1573 	}
1574 	class_destroy(sg_sysfs_class);
1575 err_out:
1576 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1577 	return rc;
1578 }
1579 
1580 static void __exit
1581 exit_sg(void)
1582 {
1583 #ifdef CONFIG_SCSI_PROC_FS
1584 	sg_proc_cleanup();
1585 #endif				/* CONFIG_SCSI_PROC_FS */
1586 	scsi_unregister_interface(&sg_interface);
1587 	class_destroy(sg_sysfs_class);
1588 	sg_sysfs_valid = 0;
1589 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1590 				 SG_MAX_DEVS);
1591 	kfree((char *)sg_dev_arr);
1592 	sg_dev_arr = NULL;
1593 	sg_dev_max = 0;
1594 }
1595 
1596 static int
1597 sg_start_req(Sg_request * srp)
1598 {
1599 	int res;
1600 	Sg_fd *sfp = srp->parentfp;
1601 	sg_io_hdr_t *hp = &srp->header;
1602 	int dxfer_len = (int) hp->dxfer_len;
1603 	int dxfer_dir = hp->dxfer_direction;
1604 	Sg_scatter_hold *req_schp = &srp->data;
1605 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1606 
1607 	SCSI_LOG_TIMEOUT(4, printk("sg_start_req: dxfer_len=%d\n", dxfer_len));
1608 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1609 		return 0;
1610 	if (sg_allow_dio && (hp->flags & SG_FLAG_DIRECT_IO) &&
1611 	    (dxfer_dir != SG_DXFER_UNKNOWN) && (0 == hp->iovec_count) &&
1612 	    (!sfp->parentdp->device->host->unchecked_isa_dma)) {
1613 		res = sg_build_direct(srp, sfp, dxfer_len);
1614 		if (res <= 0)	/* -ve -> error, 0 -> done, 1 -> try indirect */
1615 			return res;
1616 	}
1617 	if ((!sg_res_in_use(sfp)) && (dxfer_len <= rsv_schp->bufflen))
1618 		sg_link_reserve(sfp, srp, dxfer_len);
1619 	else {
1620 		res = sg_build_indirect(req_schp, sfp, dxfer_len);
1621 		if (res) {
1622 			sg_remove_scat(req_schp);
1623 			return res;
1624 		}
1625 	}
1626 	return 0;
1627 }
1628 
1629 static void
1630 sg_finish_rem_req(Sg_request * srp)
1631 {
1632 	Sg_fd *sfp = srp->parentfp;
1633 	Sg_scatter_hold *req_schp = &srp->data;
1634 
1635 	SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
1636 	if (srp->res_used)
1637 		sg_unlink_reserve(sfp, srp);
1638 	else
1639 		sg_remove_scat(req_schp);
1640 	sg_remove_request(sfp, srp);
1641 }
1642 
1643 static int
1644 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1645 {
1646 	int sg_bufflen = tablesize * sizeof(struct scatterlist);
1647 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1648 
1649 	/*
1650 	 * TODO: test without low_dma, we should not need it since
1651 	 * the block layer will bounce the buffer for us
1652 	 *
1653 	 * XXX(hch): we shouldn't need GFP_DMA for the actual S/G list.
1654 	 */
1655 	if (sfp->low_dma)
1656 		 gfp_flags |= GFP_DMA;
1657 	schp->buffer = kzalloc(sg_bufflen, gfp_flags);
1658 	if (!schp->buffer)
1659 		return -ENOMEM;
1660 	schp->sglist_len = sg_bufflen;
1661 	return tablesize;	/* number of scat_gath elements allocated */
1662 }
1663 
1664 #ifdef SG_ALLOW_DIO_CODE
1665 /* vvvvvvvv  following code borrowed from st driver's direct IO vvvvvvvvv */
1666 	/* TODO: hopefully we can use the generic block layer code */
1667 
1668 /* Pin down user pages and put them into a scatter gather list. Returns <= 0 if
1669    - mapping of all pages not successful
1670    (i.e., either completely successful or fails)
1671 */
1672 static int
1673 st_map_user_pages(struct scatterlist *sgl, const unsigned int max_pages,
1674 	          unsigned long uaddr, size_t count, int rw)
1675 {
1676 	unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
1677 	unsigned long start = uaddr >> PAGE_SHIFT;
1678 	const int nr_pages = end - start;
1679 	int res, i, j;
1680 	struct page **pages;
1681 
1682 	/* User attempted Overflow! */
1683 	if ((uaddr + count) < uaddr)
1684 		return -EINVAL;
1685 
1686 	/* Too big */
1687         if (nr_pages > max_pages)
1688 		return -ENOMEM;
1689 
1690 	/* Hmm? */
1691 	if (count == 0)
1692 		return 0;
1693 
1694 	if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_ATOMIC)) == NULL)
1695 		return -ENOMEM;
1696 
1697         /* Try to fault in all of the necessary pages */
1698 	down_read(&current->mm->mmap_sem);
1699         /* rw==READ means read from drive, write into memory area */
1700 	res = get_user_pages(
1701 		current,
1702 		current->mm,
1703 		uaddr,
1704 		nr_pages,
1705 		rw == READ,
1706 		0, /* don't force */
1707 		pages,
1708 		NULL);
1709 	up_read(&current->mm->mmap_sem);
1710 
1711 	/* Errors and no page mapped should return here */
1712 	if (res < nr_pages)
1713 		goto out_unmap;
1714 
1715         for (i=0; i < nr_pages; i++) {
1716                 /* FIXME: flush superflous for rw==READ,
1717                  * probably wrong function for rw==WRITE
1718                  */
1719 		flush_dcache_page(pages[i]);
1720 		/* ?? Is locking needed? I don't think so */
1721 		/* if (TestSetPageLocked(pages[i]))
1722 		   goto out_unlock; */
1723         }
1724 
1725 	sgl[0].page = pages[0];
1726 	sgl[0].offset = uaddr & ~PAGE_MASK;
1727 	if (nr_pages > 1) {
1728 		sgl[0].length = PAGE_SIZE - sgl[0].offset;
1729 		count -= sgl[0].length;
1730 		for (i=1; i < nr_pages ; i++) {
1731 			sgl[i].page = pages[i];
1732 			sgl[i].length = count < PAGE_SIZE ? count : PAGE_SIZE;
1733 			count -= PAGE_SIZE;
1734 		}
1735 	}
1736 	else {
1737 		sgl[0].length = count;
1738 	}
1739 
1740 	kfree(pages);
1741 	return nr_pages;
1742 
1743  out_unmap:
1744 	if (res > 0) {
1745 		for (j=0; j < res; j++)
1746 			page_cache_release(pages[j]);
1747 		res = 0;
1748 	}
1749 	kfree(pages);
1750 	return res;
1751 }
1752 
1753 
1754 /* And unmap them... */
1755 static int
1756 st_unmap_user_pages(struct scatterlist *sgl, const unsigned int nr_pages,
1757 		    int dirtied)
1758 {
1759 	int i;
1760 
1761 	for (i=0; i < nr_pages; i++) {
1762 		struct page *page = sgl[i].page;
1763 
1764 		if (dirtied)
1765 			SetPageDirty(page);
1766 		/* unlock_page(page); */
1767 		/* FIXME: cache flush missing for rw==READ
1768 		 * FIXME: call the correct reference counting function
1769 		 */
1770 		page_cache_release(page);
1771 	}
1772 
1773 	return 0;
1774 }
1775 
1776 /* ^^^^^^^^  above code borrowed from st driver's direct IO ^^^^^^^^^ */
1777 #endif
1778 
1779 
1780 /* Returns: -ve -> error, 0 -> done, 1 -> try indirect */
1781 static int
1782 sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len)
1783 {
1784 #ifdef SG_ALLOW_DIO_CODE
1785 	sg_io_hdr_t *hp = &srp->header;
1786 	Sg_scatter_hold *schp = &srp->data;
1787 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1788 	int mx_sc_elems, res;
1789 	struct scsi_device *sdev = sfp->parentdp->device;
1790 
1791 	if (((unsigned long)hp->dxferp &
1792 			queue_dma_alignment(sdev->request_queue)) != 0)
1793 		return 1;
1794 
1795 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1796         if (mx_sc_elems <= 0) {
1797                 return 1;
1798         }
1799 	res = st_map_user_pages(schp->buffer, mx_sc_elems,
1800 				(unsigned long)hp->dxferp, dxfer_len,
1801 				(SG_DXFER_TO_DEV == hp->dxfer_direction) ? 1 : 0);
1802 	if (res <= 0) {
1803 		sg_remove_scat(schp);
1804 		return 1;
1805 	}
1806 	schp->k_use_sg = res;
1807 	schp->dio_in_use = 1;
1808 	hp->info |= SG_INFO_DIRECT_IO;
1809 	return 0;
1810 #else
1811 	return 1;
1812 #endif
1813 }
1814 
1815 static int
1816 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1817 {
1818 	struct scatterlist *sg;
1819 	int ret_sz = 0, k, rem_sz, num, mx_sc_elems;
1820 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1821 	int blk_size = buff_size;
1822 	struct page *p = NULL;
1823 
1824 	if ((blk_size < 0) || (!sfp))
1825 		return -EFAULT;
1826 	if (0 == blk_size)
1827 		++blk_size;	/* don't know why */
1828 /* round request up to next highest SG_SECTOR_SZ byte boundary */
1829 	blk_size = (blk_size + SG_SECTOR_MSK) & (~SG_SECTOR_MSK);
1830 	SCSI_LOG_TIMEOUT(4, printk("sg_build_indirect: buff_size=%d, blk_size=%d\n",
1831 				   buff_size, blk_size));
1832 
1833 	/* N.B. ret_sz carried into this block ... */
1834 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1835 	if (mx_sc_elems < 0)
1836 		return mx_sc_elems;	/* most likely -ENOMEM */
1837 
1838 	for (k = 0, sg = schp->buffer, rem_sz = blk_size;
1839 	     (rem_sz > 0) && (k < mx_sc_elems);
1840 	     ++k, rem_sz -= ret_sz, ++sg) {
1841 
1842 		num = (rem_sz > SG_SCATTER_SZ) ? SG_SCATTER_SZ : rem_sz;
1843 		p = sg_page_malloc(num, sfp->low_dma, &ret_sz);
1844 		if (!p)
1845 			return -ENOMEM;
1846 
1847 		sg->page = p;
1848 		sg->length = ret_sz;
1849 
1850 		SCSI_LOG_TIMEOUT(5, printk("sg_build_build: k=%d, a=0x%p, len=%d\n",
1851 				  k, p, ret_sz));
1852 	}		/* end of for loop */
1853 
1854 	schp->k_use_sg = k;
1855 	SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, rem_sz=%d\n", k, rem_sz));
1856 
1857 	schp->bufflen = blk_size;
1858 	if (rem_sz > 0)	/* must have failed */
1859 		return -ENOMEM;
1860 
1861 	return 0;
1862 }
1863 
1864 static int
1865 sg_write_xfer(Sg_request * srp)
1866 {
1867 	sg_io_hdr_t *hp = &srp->header;
1868 	Sg_scatter_hold *schp = &srp->data;
1869 	struct scatterlist *sg = schp->buffer;
1870 	int num_xfer = 0;
1871 	int j, k, onum, usglen, ksglen, res;
1872 	int iovec_count = (int) hp->iovec_count;
1873 	int dxfer_dir = hp->dxfer_direction;
1874 	unsigned char *p;
1875 	unsigned char __user *up;
1876 	int new_interface = ('\0' == hp->interface_id) ? 0 : 1;
1877 
1878 	if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_TO_DEV == dxfer_dir) ||
1879 	    (SG_DXFER_TO_FROM_DEV == dxfer_dir)) {
1880 		num_xfer = (int) (new_interface ? hp->dxfer_len : hp->flags);
1881 		if (schp->bufflen < num_xfer)
1882 			num_xfer = schp->bufflen;
1883 	}
1884 	if ((num_xfer <= 0) || (schp->dio_in_use) ||
1885 	    (new_interface
1886 	     && ((SG_FLAG_NO_DXFER | SG_FLAG_MMAP_IO) & hp->flags)))
1887 		return 0;
1888 
1889 	SCSI_LOG_TIMEOUT(4, printk("sg_write_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n",
1890 			  num_xfer, iovec_count, schp->k_use_sg));
1891 	if (iovec_count) {
1892 		onum = iovec_count;
1893 		if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum))
1894 			return -EFAULT;
1895 	} else
1896 		onum = 1;
1897 
1898 	ksglen = sg->length;
1899 	p = page_address(sg->page);
1900 	for (j = 0, k = 0; j < onum; ++j) {
1901 		res = sg_u_iovec(hp, iovec_count, j, 1, &usglen, &up);
1902 		if (res)
1903 			return res;
1904 
1905 		for (; p; ++sg, ksglen = sg->length,
1906 		     p = page_address(sg->page)) {
1907 			if (usglen <= 0)
1908 				break;
1909 			if (ksglen > usglen) {
1910 				if (usglen >= num_xfer) {
1911 					if (__copy_from_user(p, up, num_xfer))
1912 						return -EFAULT;
1913 					return 0;
1914 				}
1915 				if (__copy_from_user(p, up, usglen))
1916 					return -EFAULT;
1917 				p += usglen;
1918 				ksglen -= usglen;
1919 				break;
1920 			} else {
1921 				if (ksglen >= num_xfer) {
1922 					if (__copy_from_user(p, up, num_xfer))
1923 						return -EFAULT;
1924 					return 0;
1925 				}
1926 				if (__copy_from_user(p, up, ksglen))
1927 					return -EFAULT;
1928 				up += ksglen;
1929 				usglen -= ksglen;
1930 			}
1931 			++k;
1932 			if (k >= schp->k_use_sg)
1933 				return 0;
1934 		}
1935 	}
1936 
1937 	return 0;
1938 }
1939 
1940 static int
1941 sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind,
1942 	   int wr_xf, int *countp, unsigned char __user **up)
1943 {
1944 	int num_xfer = (int) hp->dxfer_len;
1945 	unsigned char __user *p = hp->dxferp;
1946 	int count;
1947 
1948 	if (0 == sg_num) {
1949 		if (wr_xf && ('\0' == hp->interface_id))
1950 			count = (int) hp->flags;	/* holds "old" input_size */
1951 		else
1952 			count = num_xfer;
1953 	} else {
1954 		sg_iovec_t iovec;
1955 		if (__copy_from_user(&iovec, p + ind*SZ_SG_IOVEC, SZ_SG_IOVEC))
1956 			return -EFAULT;
1957 		p = iovec.iov_base;
1958 		count = (int) iovec.iov_len;
1959 	}
1960 	if (!access_ok(wr_xf ? VERIFY_READ : VERIFY_WRITE, p, count))
1961 		return -EFAULT;
1962 	if (up)
1963 		*up = p;
1964 	if (countp)
1965 		*countp = count;
1966 	return 0;
1967 }
1968 
1969 static void
1970 sg_remove_scat(Sg_scatter_hold * schp)
1971 {
1972 	SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1973 	if (schp->buffer && (schp->sglist_len > 0)) {
1974 		struct scatterlist *sg = schp->buffer;
1975 
1976 		if (schp->dio_in_use) {
1977 #ifdef SG_ALLOW_DIO_CODE
1978 			st_unmap_user_pages(sg, schp->k_use_sg, TRUE);
1979 #endif
1980 		} else {
1981 			int k;
1982 
1983 			for (k = 0; (k < schp->k_use_sg) && sg->page;
1984 			     ++k, ++sg) {
1985 				SCSI_LOG_TIMEOUT(5, printk(
1986 				    "sg_remove_scat: k=%d, a=0x%p, len=%d\n",
1987 				    k, sg->page, sg->length));
1988 				sg_page_free(sg->page, sg->length);
1989 			}
1990 		}
1991 		kfree(schp->buffer);
1992 	}
1993 	memset(schp, 0, sizeof (*schp));
1994 }
1995 
1996 static int
1997 sg_read_xfer(Sg_request * srp)
1998 {
1999 	sg_io_hdr_t *hp = &srp->header;
2000 	Sg_scatter_hold *schp = &srp->data;
2001 	struct scatterlist *sg = schp->buffer;
2002 	int num_xfer = 0;
2003 	int j, k, onum, usglen, ksglen, res;
2004 	int iovec_count = (int) hp->iovec_count;
2005 	int dxfer_dir = hp->dxfer_direction;
2006 	unsigned char *p;
2007 	unsigned char __user *up;
2008 	int new_interface = ('\0' == hp->interface_id) ? 0 : 1;
2009 
2010 	if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_FROM_DEV == dxfer_dir)
2011 	    || (SG_DXFER_TO_FROM_DEV == dxfer_dir)) {
2012 		num_xfer = hp->dxfer_len;
2013 		if (schp->bufflen < num_xfer)
2014 			num_xfer = schp->bufflen;
2015 	}
2016 	if ((num_xfer <= 0) || (schp->dio_in_use) ||
2017 	    (new_interface
2018 	     && ((SG_FLAG_NO_DXFER | SG_FLAG_MMAP_IO) & hp->flags)))
2019 		return 0;
2020 
2021 	SCSI_LOG_TIMEOUT(4, printk("sg_read_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n",
2022 			  num_xfer, iovec_count, schp->k_use_sg));
2023 	if (iovec_count) {
2024 		onum = iovec_count;
2025 		if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum))
2026 			return -EFAULT;
2027 	} else
2028 		onum = 1;
2029 
2030 	p = page_address(sg->page);
2031 	ksglen = sg->length;
2032 	for (j = 0, k = 0; j < onum; ++j) {
2033 		res = sg_u_iovec(hp, iovec_count, j, 0, &usglen, &up);
2034 		if (res)
2035 			return res;
2036 
2037 		for (; p; ++sg, ksglen = sg->length,
2038 		     p = page_address(sg->page)) {
2039 			if (usglen <= 0)
2040 				break;
2041 			if (ksglen > usglen) {
2042 				if (usglen >= num_xfer) {
2043 					if (__copy_to_user(up, p, num_xfer))
2044 						return -EFAULT;
2045 					return 0;
2046 				}
2047 				if (__copy_to_user(up, p, usglen))
2048 					return -EFAULT;
2049 				p += usglen;
2050 				ksglen -= usglen;
2051 				break;
2052 			} else {
2053 				if (ksglen >= num_xfer) {
2054 					if (__copy_to_user(up, p, num_xfer))
2055 						return -EFAULT;
2056 					return 0;
2057 				}
2058 				if (__copy_to_user(up, p, ksglen))
2059 					return -EFAULT;
2060 				up += ksglen;
2061 				usglen -= ksglen;
2062 			}
2063 			++k;
2064 			if (k >= schp->k_use_sg)
2065 				return 0;
2066 		}
2067 	}
2068 
2069 	return 0;
2070 }
2071 
2072 static int
2073 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
2074 {
2075 	Sg_scatter_hold *schp = &srp->data;
2076 	struct scatterlist *sg = schp->buffer;
2077 	int k, num;
2078 
2079 	SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n",
2080 				   num_read_xfer));
2081 	if ((!outp) || (num_read_xfer <= 0))
2082 		return 0;
2083 
2084 	for (k = 0; (k < schp->k_use_sg) && sg->page; ++k, ++sg) {
2085 		num = sg->length;
2086 		if (num > num_read_xfer) {
2087 			if (__copy_to_user(outp, page_address(sg->page),
2088 					   num_read_xfer))
2089 				return -EFAULT;
2090 			break;
2091 		} else {
2092 			if (__copy_to_user(outp, page_address(sg->page),
2093 					   num))
2094 				return -EFAULT;
2095 			num_read_xfer -= num;
2096 			if (num_read_xfer <= 0)
2097 				break;
2098 			outp += num;
2099 		}
2100 	}
2101 
2102 	return 0;
2103 }
2104 
2105 static void
2106 sg_build_reserve(Sg_fd * sfp, int req_size)
2107 {
2108 	Sg_scatter_hold *schp = &sfp->reserve;
2109 
2110 	SCSI_LOG_TIMEOUT(4, printk("sg_build_reserve: req_size=%d\n", req_size));
2111 	do {
2112 		if (req_size < PAGE_SIZE)
2113 			req_size = PAGE_SIZE;
2114 		if (0 == sg_build_indirect(schp, sfp, req_size))
2115 			return;
2116 		else
2117 			sg_remove_scat(schp);
2118 		req_size >>= 1;	/* divide by 2 */
2119 	} while (req_size > (PAGE_SIZE / 2));
2120 }
2121 
2122 static void
2123 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
2124 {
2125 	Sg_scatter_hold *req_schp = &srp->data;
2126 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
2127 	struct scatterlist *sg = rsv_schp->buffer;
2128 	int k, num, rem;
2129 
2130 	srp->res_used = 1;
2131 	SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
2132 	rem = size;
2133 
2134 	for (k = 0; k < rsv_schp->k_use_sg; ++k, ++sg) {
2135 		num = sg->length;
2136 		if (rem <= num) {
2137 			sfp->save_scat_len = num;
2138 			sg->length = rem;
2139 			req_schp->k_use_sg = k + 1;
2140 			req_schp->sglist_len = rsv_schp->sglist_len;
2141 			req_schp->buffer = rsv_schp->buffer;
2142 
2143 			req_schp->bufflen = size;
2144 			req_schp->b_malloc_len = rsv_schp->b_malloc_len;
2145 			break;
2146 		} else
2147 			rem -= num;
2148 	}
2149 
2150 	if (k >= rsv_schp->k_use_sg)
2151 		SCSI_LOG_TIMEOUT(1, printk("sg_link_reserve: BAD size\n"));
2152 }
2153 
2154 static void
2155 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2156 {
2157 	Sg_scatter_hold *req_schp = &srp->data;
2158 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
2159 
2160 	SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n",
2161 				   (int) req_schp->k_use_sg));
2162 	if ((rsv_schp->k_use_sg > 0) && (req_schp->k_use_sg > 0)) {
2163 		struct scatterlist *sg = rsv_schp->buffer;
2164 
2165 		if (sfp->save_scat_len > 0)
2166 			(sg + (req_schp->k_use_sg - 1))->length =
2167 			    (unsigned) sfp->save_scat_len;
2168 		else
2169 			SCSI_LOG_TIMEOUT(1, printk ("sg_unlink_reserve: BAD save_scat_len\n"));
2170 	}
2171 	req_schp->k_use_sg = 0;
2172 	req_schp->bufflen = 0;
2173 	req_schp->buffer = NULL;
2174 	req_schp->sglist_len = 0;
2175 	sfp->save_scat_len = 0;
2176 	srp->res_used = 0;
2177 }
2178 
2179 static Sg_request *
2180 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2181 {
2182 	Sg_request *resp;
2183 	unsigned long iflags;
2184 
2185 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2186 	for (resp = sfp->headrp; resp; resp = resp->nextrp) {
2187 		/* look for requests that are ready + not SG_IO owned */
2188 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
2189 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2190 			resp->done = 2;	/* guard against other readers */
2191 			break;
2192 		}
2193 	}
2194 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2195 	return resp;
2196 }
2197 
2198 #ifdef CONFIG_SCSI_PROC_FS
2199 static Sg_request *
2200 sg_get_nth_request(Sg_fd * sfp, int nth)
2201 {
2202 	Sg_request *resp;
2203 	unsigned long iflags;
2204 	int k;
2205 
2206 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2207 	for (k = 0, resp = sfp->headrp; resp && (k < nth);
2208 	     ++k, resp = resp->nextrp) ;
2209 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2210 	return resp;
2211 }
2212 #endif
2213 
2214 /* always adds to end of list */
2215 static Sg_request *
2216 sg_add_request(Sg_fd * sfp)
2217 {
2218 	int k;
2219 	unsigned long iflags;
2220 	Sg_request *resp;
2221 	Sg_request *rp = sfp->req_arr;
2222 
2223 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2224 	resp = sfp->headrp;
2225 	if (!resp) {
2226 		memset(rp, 0, sizeof (Sg_request));
2227 		rp->parentfp = sfp;
2228 		resp = rp;
2229 		sfp->headrp = resp;
2230 	} else {
2231 		if (0 == sfp->cmd_q)
2232 			resp = NULL;	/* command queuing disallowed */
2233 		else {
2234 			for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2235 				if (!rp->parentfp)
2236 					break;
2237 			}
2238 			if (k < SG_MAX_QUEUE) {
2239 				memset(rp, 0, sizeof (Sg_request));
2240 				rp->parentfp = sfp;
2241 				while (resp->nextrp)
2242 					resp = resp->nextrp;
2243 				resp->nextrp = rp;
2244 				resp = rp;
2245 			} else
2246 				resp = NULL;
2247 		}
2248 	}
2249 	if (resp) {
2250 		resp->nextrp = NULL;
2251 		resp->header.duration = jiffies_to_msecs(jiffies);
2252 	}
2253 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2254 	return resp;
2255 }
2256 
2257 /* Return of 1 for found; 0 for not found */
2258 static int
2259 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2260 {
2261 	Sg_request *prev_rp;
2262 	Sg_request *rp;
2263 	unsigned long iflags;
2264 	int res = 0;
2265 
2266 	if ((!sfp) || (!srp) || (!sfp->headrp))
2267 		return res;
2268 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2269 	prev_rp = sfp->headrp;
2270 	if (srp == prev_rp) {
2271 		sfp->headrp = prev_rp->nextrp;
2272 		prev_rp->parentfp = NULL;
2273 		res = 1;
2274 	} else {
2275 		while ((rp = prev_rp->nextrp)) {
2276 			if (srp == rp) {
2277 				prev_rp->nextrp = rp->nextrp;
2278 				rp->parentfp = NULL;
2279 				res = 1;
2280 				break;
2281 			}
2282 			prev_rp = rp;
2283 		}
2284 	}
2285 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2286 	return res;
2287 }
2288 
2289 #ifdef CONFIG_SCSI_PROC_FS
2290 static Sg_fd *
2291 sg_get_nth_sfp(Sg_device * sdp, int nth)
2292 {
2293 	Sg_fd *resp;
2294 	unsigned long iflags;
2295 	int k;
2296 
2297 	read_lock_irqsave(&sg_dev_arr_lock, iflags);
2298 	for (k = 0, resp = sdp->headfp; resp && (k < nth);
2299 	     ++k, resp = resp->nextfp) ;
2300 	read_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2301 	return resp;
2302 }
2303 #endif
2304 
2305 static Sg_fd *
2306 sg_add_sfp(Sg_device * sdp, int dev)
2307 {
2308 	Sg_fd *sfp;
2309 	unsigned long iflags;
2310 
2311 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2312 	if (!sfp)
2313 		return NULL;
2314 
2315 	init_waitqueue_head(&sfp->read_wait);
2316 	rwlock_init(&sfp->rq_list_lock);
2317 
2318 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2319 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2320 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2321 	sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2322 	    sdp->device->host->unchecked_isa_dma : 1;
2323 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2324 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2325 	sfp->parentdp = sdp;
2326 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
2327 	if (!sdp->headfp)
2328 		sdp->headfp = sfp;
2329 	else {			/* add to tail of existing list */
2330 		Sg_fd *pfp = sdp->headfp;
2331 		while (pfp->nextfp)
2332 			pfp = pfp->nextfp;
2333 		pfp->nextfp = sfp;
2334 	}
2335 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2336 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
2337 	sg_build_reserve(sfp, sg_big_buff);
2338 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp:   bufflen=%d, k_use_sg=%d\n",
2339 			   sfp->reserve.bufflen, sfp->reserve.k_use_sg));
2340 	return sfp;
2341 }
2342 
2343 static void
2344 __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2345 {
2346 	Sg_fd *fp;
2347 	Sg_fd *prev_fp;
2348 
2349 	prev_fp = sdp->headfp;
2350 	if (sfp == prev_fp)
2351 		sdp->headfp = prev_fp->nextfp;
2352 	else {
2353 		while ((fp = prev_fp->nextfp)) {
2354 			if (sfp == fp) {
2355 				prev_fp->nextfp = fp->nextfp;
2356 				break;
2357 			}
2358 			prev_fp = fp;
2359 		}
2360 	}
2361 	if (sfp->reserve.bufflen > 0) {
2362 		SCSI_LOG_TIMEOUT(6,
2363 			printk("__sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2364 			(int) sfp->reserve.bufflen, (int) sfp->reserve.k_use_sg));
2365 		sg_remove_scat(&sfp->reserve);
2366 	}
2367 	sfp->parentdp = NULL;
2368 	SCSI_LOG_TIMEOUT(6, printk("__sg_remove_sfp:    sfp=0x%p\n", sfp));
2369 	kfree(sfp);
2370 }
2371 
2372 /* Returns 0 in normal case, 1 when detached and sdp object removed */
2373 static int
2374 sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2375 {
2376 	Sg_request *srp;
2377 	Sg_request *tsrp;
2378 	int dirty = 0;
2379 	int res = 0;
2380 
2381 	for (srp = sfp->headrp; srp; srp = tsrp) {
2382 		tsrp = srp->nextrp;
2383 		if (sg_srp_done(srp, sfp))
2384 			sg_finish_rem_req(srp);
2385 		else
2386 			++dirty;
2387 	}
2388 	if (0 == dirty) {
2389 		unsigned long iflags;
2390 
2391 		write_lock_irqsave(&sg_dev_arr_lock, iflags);
2392 		__sg_remove_sfp(sdp, sfp);
2393 		if (sdp->detached && (NULL == sdp->headfp)) {
2394 			int k, maxd;
2395 
2396 			maxd = sg_dev_max;
2397 			for (k = 0; k < maxd; ++k) {
2398 				if (sdp == sg_dev_arr[k])
2399 					break;
2400 			}
2401 			if (k < maxd)
2402 				sg_dev_arr[k] = NULL;
2403 			kfree((char *) sdp);
2404 			res = 1;
2405 		}
2406 		write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2407 	} else {
2408 		/* MOD_INC's to inhibit unloading sg and associated adapter driver */
2409 		/* only bump the access_count if we actually succeeded in
2410 		 * throwing another counter on the host module */
2411 		scsi_device_get(sdp->device);	/* XXX: retval ignored? */
2412 		sfp->closed = 1;	/* flag dirty state on this fd */
2413 		SCSI_LOG_TIMEOUT(1, printk("sg_remove_sfp: worrisome, %d writes pending\n",
2414 				  dirty));
2415 	}
2416 	return res;
2417 }
2418 
2419 static int
2420 sg_res_in_use(Sg_fd * sfp)
2421 {
2422 	const Sg_request *srp;
2423 	unsigned long iflags;
2424 
2425 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2426 	for (srp = sfp->headrp; srp; srp = srp->nextrp)
2427 		if (srp->res_used)
2428 			break;
2429 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2430 	return srp ? 1 : 0;
2431 }
2432 
2433 /* If retSzp==NULL want exact size or fail */
2434 static struct page *
2435 sg_page_malloc(int rqSz, int lowDma, int *retSzp)
2436 {
2437 	struct page *resp = NULL;
2438 	gfp_t page_mask;
2439 	int order, a_size;
2440 	int resSz = rqSz;
2441 
2442 	if (rqSz <= 0)
2443 		return resp;
2444 
2445 	if (lowDma)
2446 		page_mask = GFP_ATOMIC | GFP_DMA | __GFP_COMP | __GFP_NOWARN;
2447 	else
2448 		page_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
2449 
2450 	for (order = 0, a_size = PAGE_SIZE; a_size < rqSz;
2451 	     order++, a_size <<= 1) ;
2452 	resp = alloc_pages(page_mask, order);
2453 	while ((!resp) && order && retSzp) {
2454 		--order;
2455 		a_size >>= 1;	/* divide by 2, until PAGE_SIZE */
2456 		resp =  alloc_pages(page_mask, order);	/* try half */
2457 		resSz = a_size;
2458 	}
2459 	if (resp) {
2460 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2461 			memset(page_address(resp), 0, resSz);
2462 		if (retSzp)
2463 			*retSzp = resSz;
2464 	}
2465 	return resp;
2466 }
2467 
2468 static void
2469 sg_page_free(struct page *page, int size)
2470 {
2471 	int order, a_size;
2472 
2473 	if (!page)
2474 		return;
2475 	for (order = 0, a_size = PAGE_SIZE; a_size < size;
2476 	     order++, a_size <<= 1) ;
2477 	__free_pages(page, order);
2478 }
2479 
2480 #ifndef MAINTENANCE_IN_CMD
2481 #define MAINTENANCE_IN_CMD 0xa3
2482 #endif
2483 
2484 static unsigned char allow_ops[] = { TEST_UNIT_READY, REQUEST_SENSE,
2485 	INQUIRY, READ_CAPACITY, READ_BUFFER, READ_6, READ_10, READ_12,
2486 	READ_16, MODE_SENSE, MODE_SENSE_10, LOG_SENSE, REPORT_LUNS,
2487 	SERVICE_ACTION_IN, RECEIVE_DIAGNOSTIC, READ_LONG, MAINTENANCE_IN_CMD
2488 };
2489 
2490 static int
2491 sg_allow_access(unsigned char opcode, char dev_type)
2492 {
2493 	int k;
2494 
2495 	if (TYPE_SCANNER == dev_type)	/* TYPE_ROM maybe burner */
2496 		return 1;
2497 	for (k = 0; k < sizeof (allow_ops); ++k) {
2498 		if (opcode == allow_ops[k])
2499 			return 1;
2500 	}
2501 	return 0;
2502 }
2503 
2504 #ifdef CONFIG_SCSI_PROC_FS
2505 static int
2506 sg_last_dev(void)
2507 {
2508 	int k;
2509 	unsigned long iflags;
2510 
2511 	read_lock_irqsave(&sg_dev_arr_lock, iflags);
2512 	for (k = sg_dev_max - 1; k >= 0; --k)
2513 		if (sg_dev_arr[k] && sg_dev_arr[k]->device)
2514 			break;
2515 	read_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2516 	return k + 1;		/* origin 1 */
2517 }
2518 #endif
2519 
2520 static Sg_device *
2521 sg_get_dev(int dev)
2522 {
2523 	Sg_device *sdp = NULL;
2524 	unsigned long iflags;
2525 
2526 	if (sg_dev_arr && (dev >= 0)) {
2527 		read_lock_irqsave(&sg_dev_arr_lock, iflags);
2528 		if (dev < sg_dev_max)
2529 			sdp = sg_dev_arr[dev];
2530 		read_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2531 	}
2532 	return sdp;
2533 }
2534 
2535 #ifdef CONFIG_SCSI_PROC_FS
2536 
2537 static struct proc_dir_entry *sg_proc_sgp = NULL;
2538 
2539 static char sg_proc_sg_dirname[] = "scsi/sg";
2540 
2541 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2542 
2543 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2544 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2545 			          size_t count, loff_t *off);
2546 static struct file_operations adio_fops = {
2547 	/* .owner, .read and .llseek added in sg_proc_init() */
2548 	.open = sg_proc_single_open_adio,
2549 	.write = sg_proc_write_adio,
2550 	.release = single_release,
2551 };
2552 
2553 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2554 static ssize_t sg_proc_write_dressz(struct file *filp,
2555 		const char __user *buffer, size_t count, loff_t *off);
2556 static struct file_operations dressz_fops = {
2557 	.open = sg_proc_single_open_dressz,
2558 	.write = sg_proc_write_dressz,
2559 	.release = single_release,
2560 };
2561 
2562 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2563 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2564 static struct file_operations version_fops = {
2565 	.open = sg_proc_single_open_version,
2566 	.release = single_release,
2567 };
2568 
2569 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2570 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2571 static struct file_operations devhdr_fops = {
2572 	.open = sg_proc_single_open_devhdr,
2573 	.release = single_release,
2574 };
2575 
2576 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2577 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2578 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2579 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2580 static void dev_seq_stop(struct seq_file *s, void *v);
2581 static struct file_operations dev_fops = {
2582 	.open = sg_proc_open_dev,
2583 	.release = seq_release,
2584 };
2585 static struct seq_operations dev_seq_ops = {
2586 	.start = dev_seq_start,
2587 	.next  = dev_seq_next,
2588 	.stop  = dev_seq_stop,
2589 	.show  = sg_proc_seq_show_dev,
2590 };
2591 
2592 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2593 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2594 static struct file_operations devstrs_fops = {
2595 	.open = sg_proc_open_devstrs,
2596 	.release = seq_release,
2597 };
2598 static struct seq_operations devstrs_seq_ops = {
2599 	.start = dev_seq_start,
2600 	.next  = dev_seq_next,
2601 	.stop  = dev_seq_stop,
2602 	.show  = sg_proc_seq_show_devstrs,
2603 };
2604 
2605 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2606 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2607 static struct file_operations debug_fops = {
2608 	.open = sg_proc_open_debug,
2609 	.release = seq_release,
2610 };
2611 static struct seq_operations debug_seq_ops = {
2612 	.start = dev_seq_start,
2613 	.next  = dev_seq_next,
2614 	.stop  = dev_seq_stop,
2615 	.show  = sg_proc_seq_show_debug,
2616 };
2617 
2618 
2619 struct sg_proc_leaf {
2620 	const char * name;
2621 	struct file_operations * fops;
2622 };
2623 
2624 static struct sg_proc_leaf sg_proc_leaf_arr[] = {
2625 	{"allow_dio", &adio_fops},
2626 	{"debug", &debug_fops},
2627 	{"def_reserved_size", &dressz_fops},
2628 	{"device_hdr", &devhdr_fops},
2629 	{"devices", &dev_fops},
2630 	{"device_strs", &devstrs_fops},
2631 	{"version", &version_fops}
2632 };
2633 
2634 static int
2635 sg_proc_init(void)
2636 {
2637 	int k, mask;
2638 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2639 	struct proc_dir_entry *pdep;
2640 	struct sg_proc_leaf * leaf;
2641 
2642 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2643 	if (!sg_proc_sgp)
2644 		return 1;
2645 	for (k = 0; k < num_leaves; ++k) {
2646 		leaf = &sg_proc_leaf_arr[k];
2647 		mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2648 		pdep = create_proc_entry(leaf->name, mask, sg_proc_sgp);
2649 		if (pdep) {
2650 			leaf->fops->owner = THIS_MODULE,
2651 			leaf->fops->read = seq_read,
2652 			leaf->fops->llseek = seq_lseek,
2653 			pdep->proc_fops = leaf->fops;
2654 		}
2655 	}
2656 	return 0;
2657 }
2658 
2659 static void
2660 sg_proc_cleanup(void)
2661 {
2662 	int k;
2663 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2664 
2665 	if (!sg_proc_sgp)
2666 		return;
2667 	for (k = 0; k < num_leaves; ++k)
2668 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2669 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2670 }
2671 
2672 
2673 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2674 {
2675 	seq_printf(s, "%d\n", *((int *)s->private));
2676 	return 0;
2677 }
2678 
2679 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2680 {
2681 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2682 }
2683 
2684 static ssize_t
2685 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2686 		   size_t count, loff_t *off)
2687 {
2688 	int num;
2689 	char buff[11];
2690 
2691 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2692 		return -EACCES;
2693 	num = (count < 10) ? count : 10;
2694 	if (copy_from_user(buff, buffer, num))
2695 		return -EFAULT;
2696 	buff[num] = '\0';
2697 	sg_allow_dio = simple_strtoul(buff, NULL, 10) ? 1 : 0;
2698 	return count;
2699 }
2700 
2701 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2702 {
2703 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2704 }
2705 
2706 static ssize_t
2707 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2708 		     size_t count, loff_t *off)
2709 {
2710 	int num;
2711 	unsigned long k = ULONG_MAX;
2712 	char buff[11];
2713 
2714 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2715 		return -EACCES;
2716 	num = (count < 10) ? count : 10;
2717 	if (copy_from_user(buff, buffer, num))
2718 		return -EFAULT;
2719 	buff[num] = '\0';
2720 	k = simple_strtoul(buff, NULL, 10);
2721 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2722 		sg_big_buff = k;
2723 		return count;
2724 	}
2725 	return -ERANGE;
2726 }
2727 
2728 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2729 {
2730 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2731 		   sg_version_date);
2732 	return 0;
2733 }
2734 
2735 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2736 {
2737 	return single_open(file, sg_proc_seq_show_version, NULL);
2738 }
2739 
2740 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2741 {
2742 	seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
2743 		   "online\n");
2744 	return 0;
2745 }
2746 
2747 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2748 {
2749 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2750 }
2751 
2752 struct sg_proc_deviter {
2753 	loff_t	index;
2754 	size_t	max;
2755 };
2756 
2757 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2758 {
2759 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2760 
2761 	s->private = it;
2762 	if (! it)
2763 		return NULL;
2764 
2765 	if (NULL == sg_dev_arr)
2766 		return NULL;
2767 	it->index = *pos;
2768 	it->max = sg_last_dev();
2769 	if (it->index >= it->max)
2770 		return NULL;
2771 	return it;
2772 }
2773 
2774 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2775 {
2776 	struct sg_proc_deviter * it = s->private;
2777 
2778 	*pos = ++it->index;
2779 	return (it->index < it->max) ? it : NULL;
2780 }
2781 
2782 static void dev_seq_stop(struct seq_file *s, void *v)
2783 {
2784 	kfree(s->private);
2785 }
2786 
2787 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2788 {
2789         return seq_open(file, &dev_seq_ops);
2790 }
2791 
2792 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2793 {
2794 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2795 	Sg_device *sdp;
2796 	struct scsi_device *scsidp;
2797 
2798 	sdp = it ? sg_get_dev(it->index) : NULL;
2799 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2800 		seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
2801 			      scsidp->host->host_no, scsidp->channel,
2802 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2803 			      1,
2804 			      (int) scsidp->queue_depth,
2805 			      (int) scsidp->device_busy,
2806 			      (int) scsi_device_online(scsidp));
2807 	else
2808 		seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2809 	return 0;
2810 }
2811 
2812 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2813 {
2814         return seq_open(file, &devstrs_seq_ops);
2815 }
2816 
2817 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2818 {
2819 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2820 	Sg_device *sdp;
2821 	struct scsi_device *scsidp;
2822 
2823 	sdp = it ? sg_get_dev(it->index) : NULL;
2824 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2825 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2826 			   scsidp->vendor, scsidp->model, scsidp->rev);
2827 	else
2828 		seq_printf(s, "<no active device>\n");
2829 	return 0;
2830 }
2831 
2832 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2833 {
2834 	int k, m, new_interface, blen, usg;
2835 	Sg_request *srp;
2836 	Sg_fd *fp;
2837 	const sg_io_hdr_t *hp;
2838 	const char * cp;
2839 	unsigned int ms;
2840 
2841 	for (k = 0; (fp = sg_get_nth_sfp(sdp, k)); ++k) {
2842 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2843 			   "(res)sgat=%d low_dma=%d\n", k + 1,
2844 			   jiffies_to_msecs(fp->timeout),
2845 			   fp->reserve.bufflen,
2846 			   (int) fp->reserve.k_use_sg,
2847 			   (int) fp->low_dma);
2848 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=%d\n",
2849 			   (int) fp->cmd_q, (int) fp->force_packid,
2850 			   (int) fp->keep_orphan, (int) fp->closed);
2851 		for (m = 0; (srp = sg_get_nth_request(fp, m)); ++m) {
2852 			hp = &srp->header;
2853 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2854 			if (srp->res_used) {
2855 				if (new_interface &&
2856 				    (SG_FLAG_MMAP_IO & hp->flags))
2857 					cp = "     mmap>> ";
2858 				else
2859 					cp = "     rb>> ";
2860 			} else {
2861 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2862 					cp = "     dio>> ";
2863 				else
2864 					cp = "     ";
2865 			}
2866 			seq_printf(s, cp);
2867 			blen = srp->data.bufflen;
2868 			usg = srp->data.k_use_sg;
2869 			seq_printf(s, srp->done ?
2870 				   ((1 == srp->done) ?  "rcv:" : "fin:")
2871 				   : "act:");
2872 			seq_printf(s, " id=%d blen=%d",
2873 				   srp->header.pack_id, blen);
2874 			if (srp->done)
2875 				seq_printf(s, " dur=%d", hp->duration);
2876 			else {
2877 				ms = jiffies_to_msecs(jiffies);
2878 				seq_printf(s, " t_o/elap=%d/%d",
2879 					(new_interface ? hp->timeout :
2880 						  jiffies_to_msecs(fp->timeout)),
2881 					(ms > hp->duration ? ms - hp->duration : 0));
2882 			}
2883 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2884 				   (int) srp->data.cmd_opcode);
2885 		}
2886 		if (0 == m)
2887 			seq_printf(s, "     No requests active\n");
2888 	}
2889 }
2890 
2891 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2892 {
2893         return seq_open(file, &debug_seq_ops);
2894 }
2895 
2896 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2897 {
2898 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2899 	Sg_device *sdp;
2900 
2901 	if (it && (0 == it->index)) {
2902 		seq_printf(s, "dev_max(currently)=%d max_active_device=%d "
2903 			   "(origin 1)\n", sg_dev_max, (int)it->max);
2904 		seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
2905 	}
2906 	sdp = it ? sg_get_dev(it->index) : NULL;
2907 	if (sdp) {
2908 		struct scsi_device *scsidp = sdp->device;
2909 
2910 		if (NULL == scsidp) {
2911 			seq_printf(s, "device %d detached ??\n",
2912 				   (int)it->index);
2913 			return 0;
2914 		}
2915 
2916 		if (sg_get_nth_sfp(sdp, 0)) {
2917 			seq_printf(s, " >>> device=%s ",
2918 				sdp->disk->disk_name);
2919 			if (sdp->detached)
2920 				seq_printf(s, "detached pending close ");
2921 			else
2922 				seq_printf
2923 				    (s, "scsi%d chan=%d id=%d lun=%d   em=%d",
2924 				     scsidp->host->host_no,
2925 				     scsidp->channel, scsidp->id,
2926 				     scsidp->lun,
2927 				     scsidp->host->hostt->emulated);
2928 			seq_printf(s, " sg_tablesize=%d excl=%d\n",
2929 				   sdp->sg_tablesize, sdp->exclude);
2930 		}
2931 		sg_proc_debug_helper(s, sdp);
2932 	}
2933 	return 0;
2934 }
2935 
2936 #endif				/* CONFIG_SCSI_PROC_FS */
2937 
2938 module_init(init_sg);
2939 module_exit(exit_sg);
2940