xref: /linux/drivers/scsi/sg.c (revision de2fe5e07d58424bc286fff3fd3c1b0bf933cd58)
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 		return -ENOMEM;
752 	} else
753 		return 0;
754 }
755 
756 static int
757 sg_srp_done(Sg_request *srp, Sg_fd *sfp)
758 {
759 	unsigned long iflags;
760 	int done;
761 
762 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
763 	done = srp->done;
764 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
765 	return done;
766 }
767 
768 static int
769 sg_ioctl(struct inode *inode, struct file *filp,
770 	 unsigned int cmd_in, unsigned long arg)
771 {
772 	void __user *p = (void __user *)arg;
773 	int __user *ip = p;
774 	int result, val, read_only;
775 	Sg_device *sdp;
776 	Sg_fd *sfp;
777 	Sg_request *srp;
778 	unsigned long iflags;
779 
780 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
781 		return -ENXIO;
782 	SCSI_LOG_TIMEOUT(3, printk("sg_ioctl: %s, cmd=0x%x\n",
783 				   sdp->disk->disk_name, (int) cmd_in));
784 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
785 
786 	switch (cmd_in) {
787 	case SG_IO:
788 		{
789 			int blocking = 1;	/* ignore O_NONBLOCK flag */
790 
791 			if (sdp->detached)
792 				return -ENODEV;
793 			if (!scsi_block_when_processing_errors(sdp->device))
794 				return -ENXIO;
795 			if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
796 				return -EFAULT;
797 			result =
798 			    sg_new_write(sfp, p, SZ_SG_IO_HDR,
799 					 blocking, read_only, &srp);
800 			if (result < 0)
801 				return result;
802 			srp->sg_io_owned = 1;
803 			while (1) {
804 				result = 0;	/* following macro to beat race condition */
805 				__wait_event_interruptible(sfp->read_wait,
806 					(sdp->detached || sfp->closed || sg_srp_done(srp, sfp)),
807 							   result);
808 				if (sdp->detached)
809 					return -ENODEV;
810 				if (sfp->closed)
811 					return 0;	/* request packet dropped already */
812 				if (0 == result)
813 					break;
814 				srp->orphan = 1;
815 				return result;	/* -ERESTARTSYS because signal hit process */
816 			}
817 			write_lock_irqsave(&sfp->rq_list_lock, iflags);
818 			srp->done = 2;
819 			write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
820 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
821 			return (result < 0) ? result : 0;
822 		}
823 	case SG_SET_TIMEOUT:
824 		result = get_user(val, ip);
825 		if (result)
826 			return result;
827 		if (val < 0)
828 			return -EIO;
829 		if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
830 		    val = MULDIV (INT_MAX, USER_HZ, HZ);
831 		sfp->timeout_user = val;
832 		sfp->timeout = MULDIV (val, HZ, USER_HZ);
833 
834 		return 0;
835 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
836 				/* strange ..., for backward compatibility */
837 		return sfp->timeout_user;
838 	case SG_SET_FORCE_LOW_DMA:
839 		result = get_user(val, ip);
840 		if (result)
841 			return result;
842 		if (val) {
843 			sfp->low_dma = 1;
844 			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
845 				val = (int) sfp->reserve.bufflen;
846 				sg_remove_scat(&sfp->reserve);
847 				sg_build_reserve(sfp, val);
848 			}
849 		} else {
850 			if (sdp->detached)
851 				return -ENODEV;
852 			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
853 		}
854 		return 0;
855 	case SG_GET_LOW_DMA:
856 		return put_user((int) sfp->low_dma, ip);
857 	case SG_GET_SCSI_ID:
858 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
859 			return -EFAULT;
860 		else {
861 			sg_scsi_id_t __user *sg_idp = p;
862 
863 			if (sdp->detached)
864 				return -ENODEV;
865 			__put_user((int) sdp->device->host->host_no,
866 				   &sg_idp->host_no);
867 			__put_user((int) sdp->device->channel,
868 				   &sg_idp->channel);
869 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
870 			__put_user((int) sdp->device->lun, &sg_idp->lun);
871 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
872 			__put_user((short) sdp->device->host->cmd_per_lun,
873 				   &sg_idp->h_cmd_per_lun);
874 			__put_user((short) sdp->device->queue_depth,
875 				   &sg_idp->d_queue_depth);
876 			__put_user(0, &sg_idp->unused[0]);
877 			__put_user(0, &sg_idp->unused[1]);
878 			return 0;
879 		}
880 	case SG_SET_FORCE_PACK_ID:
881 		result = get_user(val, ip);
882 		if (result)
883 			return result;
884 		sfp->force_packid = val ? 1 : 0;
885 		return 0;
886 	case SG_GET_PACK_ID:
887 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
888 			return -EFAULT;
889 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
890 		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
891 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
892 				read_unlock_irqrestore(&sfp->rq_list_lock,
893 						       iflags);
894 				__put_user(srp->header.pack_id, ip);
895 				return 0;
896 			}
897 		}
898 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
899 		__put_user(-1, ip);
900 		return 0;
901 	case SG_GET_NUM_WAITING:
902 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
903 		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
904 			if ((1 == srp->done) && (!srp->sg_io_owned))
905 				++val;
906 		}
907 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
908 		return put_user(val, ip);
909 	case SG_GET_SG_TABLESIZE:
910 		return put_user(sdp->sg_tablesize, ip);
911 	case SG_SET_RESERVED_SIZE:
912 		result = get_user(val, ip);
913 		if (result)
914 			return result;
915                 if (val < 0)
916                         return -EINVAL;
917 		if (val != sfp->reserve.bufflen) {
918 			if (sg_res_in_use(sfp) || sfp->mmap_called)
919 				return -EBUSY;
920 			sg_remove_scat(&sfp->reserve);
921 			sg_build_reserve(sfp, val);
922 		}
923 		return 0;
924 	case SG_GET_RESERVED_SIZE:
925 		val = (int) sfp->reserve.bufflen;
926 		return put_user(val, ip);
927 	case SG_SET_COMMAND_Q:
928 		result = get_user(val, ip);
929 		if (result)
930 			return result;
931 		sfp->cmd_q = val ? 1 : 0;
932 		return 0;
933 	case SG_GET_COMMAND_Q:
934 		return put_user((int) sfp->cmd_q, ip);
935 	case SG_SET_KEEP_ORPHAN:
936 		result = get_user(val, ip);
937 		if (result)
938 			return result;
939 		sfp->keep_orphan = val;
940 		return 0;
941 	case SG_GET_KEEP_ORPHAN:
942 		return put_user((int) sfp->keep_orphan, ip);
943 	case SG_NEXT_CMD_LEN:
944 		result = get_user(val, ip);
945 		if (result)
946 			return result;
947 		sfp->next_cmd_len = (val > 0) ? val : 0;
948 		return 0;
949 	case SG_GET_VERSION_NUM:
950 		return put_user(sg_version_num, ip);
951 	case SG_GET_ACCESS_COUNT:
952 		/* faked - we don't have a real access count anymore */
953 		val = (sdp->device ? 1 : 0);
954 		return put_user(val, ip);
955 	case SG_GET_REQUEST_TABLE:
956 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
957 			return -EFAULT;
958 		else {
959 			sg_req_info_t *rinfo;
960 			unsigned int ms;
961 
962 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
963 								GFP_KERNEL);
964 			if (!rinfo)
965 				return -ENOMEM;
966 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
967 			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
968 			     ++val, srp = srp ? srp->nextrp : srp) {
969 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
970 				if (srp) {
971 					rinfo[val].req_state = srp->done + 1;
972 					rinfo[val].problem =
973 					    srp->header.masked_status &
974 					    srp->header.host_status &
975 					    srp->header.driver_status;
976 					if (srp->done)
977 						rinfo[val].duration =
978 							srp->header.duration;
979 					else {
980 						ms = jiffies_to_msecs(jiffies);
981 						rinfo[val].duration =
982 						    (ms > srp->header.duration) ?
983 						    (ms - srp->header.duration) : 0;
984 					}
985 					rinfo[val].orphan = srp->orphan;
986 					rinfo[val].sg_io_owned =
987 							srp->sg_io_owned;
988 					rinfo[val].pack_id =
989 							srp->header.pack_id;
990 					rinfo[val].usr_ptr =
991 							srp->header.usr_ptr;
992 				}
993 			}
994 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
995 			result = __copy_to_user(p, rinfo,
996 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
997 			result = result ? -EFAULT : 0;
998 			kfree(rinfo);
999 			return result;
1000 		}
1001 	case SG_EMULATED_HOST:
1002 		if (sdp->detached)
1003 			return -ENODEV;
1004 		return put_user(sdp->device->host->hostt->emulated, ip);
1005 	case SG_SCSI_RESET:
1006 		if (sdp->detached)
1007 			return -ENODEV;
1008 		if (filp->f_flags & O_NONBLOCK) {
1009 			if (scsi_host_in_recovery(sdp->device->host))
1010 				return -EBUSY;
1011 		} else if (!scsi_block_when_processing_errors(sdp->device))
1012 			return -EBUSY;
1013 		result = get_user(val, ip);
1014 		if (result)
1015 			return result;
1016 		if (SG_SCSI_RESET_NOTHING == val)
1017 			return 0;
1018 		switch (val) {
1019 		case SG_SCSI_RESET_DEVICE:
1020 			val = SCSI_TRY_RESET_DEVICE;
1021 			break;
1022 		case SG_SCSI_RESET_BUS:
1023 			val = SCSI_TRY_RESET_BUS;
1024 			break;
1025 		case SG_SCSI_RESET_HOST:
1026 			val = SCSI_TRY_RESET_HOST;
1027 			break;
1028 		default:
1029 			return -EINVAL;
1030 		}
1031 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1032 			return -EACCES;
1033 		return (scsi_reset_provider(sdp->device, val) ==
1034 			SUCCESS) ? 0 : -EIO;
1035 	case SCSI_IOCTL_SEND_COMMAND:
1036 		if (sdp->detached)
1037 			return -ENODEV;
1038 		if (read_only) {
1039 			unsigned char opcode = WRITE_6;
1040 			Scsi_Ioctl_Command __user *siocp = p;
1041 
1042 			if (copy_from_user(&opcode, siocp->data, 1))
1043 				return -EFAULT;
1044 			if (!sg_allow_access(opcode, sdp->device->type))
1045 				return -EPERM;
1046 		}
1047 		return scsi_ioctl_send_command(sdp->device, p);
1048 	case SG_SET_DEBUG:
1049 		result = get_user(val, ip);
1050 		if (result)
1051 			return result;
1052 		sdp->sgdebug = (char) val;
1053 		return 0;
1054 	case SCSI_IOCTL_GET_IDLUN:
1055 	case SCSI_IOCTL_GET_BUS_NUMBER:
1056 	case SCSI_IOCTL_PROBE_HOST:
1057 	case SG_GET_TRANSFORM:
1058 		if (sdp->detached)
1059 			return -ENODEV;
1060 		return scsi_ioctl(sdp->device, cmd_in, p);
1061 	default:
1062 		if (read_only)
1063 			return -EPERM;	/* don't know so take safe approach */
1064 		return scsi_ioctl(sdp->device, cmd_in, p);
1065 	}
1066 }
1067 
1068 #ifdef CONFIG_COMPAT
1069 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1070 {
1071 	Sg_device *sdp;
1072 	Sg_fd *sfp;
1073 	struct scsi_device *sdev;
1074 
1075 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1076 		return -ENXIO;
1077 
1078 	sdev = sdp->device;
1079 	if (sdev->host->hostt->compat_ioctl) {
1080 		int ret;
1081 
1082 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1083 
1084 		return ret;
1085 	}
1086 
1087 	return -ENOIOCTLCMD;
1088 }
1089 #endif
1090 
1091 static unsigned int
1092 sg_poll(struct file *filp, poll_table * wait)
1093 {
1094 	unsigned int res = 0;
1095 	Sg_device *sdp;
1096 	Sg_fd *sfp;
1097 	Sg_request *srp;
1098 	int count = 0;
1099 	unsigned long iflags;
1100 
1101 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))
1102 	    || sfp->closed)
1103 		return POLLERR;
1104 	poll_wait(filp, &sfp->read_wait, wait);
1105 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1106 	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1107 		/* if any read waiting, flag it */
1108 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1109 			res = POLLIN | POLLRDNORM;
1110 		++count;
1111 	}
1112 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1113 
1114 	if (sdp->detached)
1115 		res |= POLLHUP;
1116 	else if (!sfp->cmd_q) {
1117 		if (0 == count)
1118 			res |= POLLOUT | POLLWRNORM;
1119 	} else if (count < SG_MAX_QUEUE)
1120 		res |= POLLOUT | POLLWRNORM;
1121 	SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
1122 				   sdp->disk->disk_name, (int) res));
1123 	return res;
1124 }
1125 
1126 static int
1127 sg_fasync(int fd, struct file *filp, int mode)
1128 {
1129 	int retval;
1130 	Sg_device *sdp;
1131 	Sg_fd *sfp;
1132 
1133 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1134 		return -ENXIO;
1135 	SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
1136 				   sdp->disk->disk_name, mode));
1137 
1138 	retval = fasync_helper(fd, filp, mode, &sfp->async_qp);
1139 	return (retval < 0) ? retval : 0;
1140 }
1141 
1142 static struct page *
1143 sg_vma_nopage(struct vm_area_struct *vma, unsigned long addr, int *type)
1144 {
1145 	Sg_fd *sfp;
1146 	struct page *page = NOPAGE_SIGBUS;
1147 	unsigned long offset, len, sa;
1148 	Sg_scatter_hold *rsv_schp;
1149 	struct scatterlist *sg;
1150 	int k;
1151 
1152 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1153 		return page;
1154 	rsv_schp = &sfp->reserve;
1155 	offset = addr - vma->vm_start;
1156 	if (offset >= rsv_schp->bufflen)
1157 		return page;
1158 	SCSI_LOG_TIMEOUT(3, printk("sg_vma_nopage: offset=%lu, scatg=%d\n",
1159 				   offset, rsv_schp->k_use_sg));
1160 	sg = rsv_schp->buffer;
1161 	sa = vma->vm_start;
1162 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
1163 	     ++k, ++sg) {
1164 		len = vma->vm_end - sa;
1165 		len = (len < sg->length) ? len : sg->length;
1166 		if (offset < len) {
1167 			page = sg->page;
1168 			get_page(page);	/* increment page count */
1169 			break;
1170 		}
1171 		sa += len;
1172 		offset -= len;
1173 	}
1174 
1175 	if (type)
1176 		*type = VM_FAULT_MINOR;
1177 	return page;
1178 }
1179 
1180 static struct vm_operations_struct sg_mmap_vm_ops = {
1181 	.nopage = sg_vma_nopage,
1182 };
1183 
1184 static int
1185 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1186 {
1187 	Sg_fd *sfp;
1188 	unsigned long req_sz, len, sa;
1189 	Sg_scatter_hold *rsv_schp;
1190 	int k;
1191 	struct scatterlist *sg;
1192 
1193 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1194 		return -ENXIO;
1195 	req_sz = vma->vm_end - vma->vm_start;
1196 	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
1197 				   (void *) vma->vm_start, (int) req_sz));
1198 	if (vma->vm_pgoff)
1199 		return -EINVAL;	/* want no offset */
1200 	rsv_schp = &sfp->reserve;
1201 	if (req_sz > rsv_schp->bufflen)
1202 		return -ENOMEM;	/* cannot map more than reserved buffer */
1203 
1204 	sa = vma->vm_start;
1205 	sg = rsv_schp->buffer;
1206 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
1207 	     ++k, ++sg) {
1208 		len = vma->vm_end - sa;
1209 		len = (len < sg->length) ? len : sg->length;
1210 		sa += len;
1211 	}
1212 
1213 	sfp->mmap_called = 1;
1214 	vma->vm_flags |= VM_RESERVED;
1215 	vma->vm_private_data = sfp;
1216 	vma->vm_ops = &sg_mmap_vm_ops;
1217 	return 0;
1218 }
1219 
1220 /* This function is a "bottom half" handler that is called by the
1221  * mid level when a command is completed (or has failed). */
1222 static void
1223 sg_cmd_done(void *data, char *sense, int result, int resid)
1224 {
1225 	Sg_request *srp = data;
1226 	Sg_device *sdp = NULL;
1227 	Sg_fd *sfp;
1228 	unsigned long iflags;
1229 	unsigned int ms;
1230 
1231 	if (NULL == srp) {
1232 		printk(KERN_ERR "sg_cmd_done: NULL request\n");
1233 		return;
1234 	}
1235 	sfp = srp->parentfp;
1236 	if (sfp)
1237 		sdp = sfp->parentdp;
1238 	if ((NULL == sdp) || sdp->detached) {
1239 		printk(KERN_INFO "sg_cmd_done: device detached\n");
1240 		return;
1241 	}
1242 
1243 
1244 	SCSI_LOG_TIMEOUT(4, printk("sg_cmd_done: %s, pack_id=%d, res=0x%x\n",
1245 		sdp->disk->disk_name, srp->header.pack_id, result));
1246 	srp->header.resid = resid;
1247 	ms = jiffies_to_msecs(jiffies);
1248 	srp->header.duration = (ms > srp->header.duration) ?
1249 				(ms - srp->header.duration) : 0;
1250 	if (0 != result) {
1251 		struct scsi_sense_hdr sshdr;
1252 
1253 		memcpy(srp->sense_b, sense, sizeof (srp->sense_b));
1254 		srp->header.status = 0xff & result;
1255 		srp->header.masked_status = status_byte(result);
1256 		srp->header.msg_status = msg_byte(result);
1257 		srp->header.host_status = host_byte(result);
1258 		srp->header.driver_status = driver_byte(result);
1259 		if ((sdp->sgdebug > 0) &&
1260 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1261 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1262 			__scsi_print_sense("sg_cmd_done", sense,
1263 					   SCSI_SENSE_BUFFERSIZE);
1264 
1265 		/* Following if statement is a patch supplied by Eric Youngdale */
1266 		if (driver_byte(result) != 0
1267 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1268 		    && !scsi_sense_is_deferred(&sshdr)
1269 		    && sshdr.sense_key == UNIT_ATTENTION
1270 		    && sdp->device->removable) {
1271 			/* Detected possible disc change. Set the bit - this */
1272 			/* may be used if there are filesystems using this device */
1273 			sdp->device->changed = 1;
1274 		}
1275 	}
1276 	/* Rely on write phase to clean out srp status values, so no "else" */
1277 
1278 	if (sfp->closed) {	/* whoops this fd already released, cleanup */
1279 		SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, freeing ...\n"));
1280 		sg_finish_rem_req(srp);
1281 		srp = NULL;
1282 		if (NULL == sfp->headrp) {
1283 			SCSI_LOG_TIMEOUT(1, printk("sg...bh: already closed, final cleanup\n"));
1284 			if (0 == sg_remove_sfp(sdp, sfp)) {	/* device still present */
1285 				scsi_device_put(sdp->device);
1286 			}
1287 			sfp = NULL;
1288 		}
1289 	} else if (srp && srp->orphan) {
1290 		if (sfp->keep_orphan)
1291 			srp->sg_io_owned = 0;
1292 		else {
1293 			sg_finish_rem_req(srp);
1294 			srp = NULL;
1295 		}
1296 	}
1297 	if (sfp && srp) {
1298 		/* Now wake up any sg_read() that is waiting for this packet. */
1299 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1300 		write_lock_irqsave(&sfp->rq_list_lock, iflags);
1301 		srp->done = 1;
1302 		wake_up_interruptible(&sfp->read_wait);
1303 		write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1304 	}
1305 }
1306 
1307 static struct file_operations sg_fops = {
1308 	.owner = THIS_MODULE,
1309 	.read = sg_read,
1310 	.write = sg_write,
1311 	.poll = sg_poll,
1312 	.ioctl = sg_ioctl,
1313 #ifdef CONFIG_COMPAT
1314 	.compat_ioctl = sg_compat_ioctl,
1315 #endif
1316 	.open = sg_open,
1317 	.mmap = sg_mmap,
1318 	.release = sg_release,
1319 	.fasync = sg_fasync,
1320 };
1321 
1322 static struct class *sg_sysfs_class;
1323 
1324 static int sg_sysfs_valid = 0;
1325 
1326 static int sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1327 {
1328 	struct request_queue *q = scsidp->request_queue;
1329 	Sg_device *sdp;
1330 	unsigned long iflags;
1331 	void *old_sg_dev_arr = NULL;
1332 	int k, error;
1333 
1334 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1335 	if (!sdp) {
1336 		printk(KERN_WARNING "kmalloc Sg_device failure\n");
1337 		return -ENOMEM;
1338 	}
1339 
1340 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
1341 	if (unlikely(sg_nr_dev >= sg_dev_max)) {	/* try to resize */
1342 		Sg_device **tmp_da;
1343 		int tmp_dev_max = sg_nr_dev + SG_DEV_ARR_LUMP;
1344 		write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1345 
1346 		tmp_da = kzalloc(tmp_dev_max * sizeof(Sg_device *), GFP_KERNEL);
1347 		if (unlikely(!tmp_da))
1348 			goto expand_failed;
1349 
1350 		write_lock_irqsave(&sg_dev_arr_lock, iflags);
1351 		memcpy(tmp_da, sg_dev_arr, sg_dev_max * sizeof(Sg_device *));
1352 		old_sg_dev_arr = sg_dev_arr;
1353 		sg_dev_arr = tmp_da;
1354 		sg_dev_max = tmp_dev_max;
1355 	}
1356 
1357 	for (k = 0; k < sg_dev_max; k++)
1358 		if (!sg_dev_arr[k])
1359 			break;
1360 	if (unlikely(k >= SG_MAX_DEVS))
1361 		goto overflow;
1362 
1363 	SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
1364 	sprintf(disk->disk_name, "sg%d", k);
1365 	disk->first_minor = k;
1366 	sdp->disk = disk;
1367 	sdp->device = scsidp;
1368 	init_waitqueue_head(&sdp->o_excl_wait);
1369 	sdp->sg_tablesize = min(q->max_hw_segments, q->max_phys_segments);
1370 
1371 	sg_nr_dev++;
1372 	sg_dev_arr[k] = sdp;
1373 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1374 	error = k;
1375 
1376  out:
1377 	if (error < 0)
1378 		kfree(sdp);
1379 	kfree(old_sg_dev_arr);
1380 	return error;
1381 
1382  expand_failed:
1383 	printk(KERN_WARNING "sg_alloc: device array cannot be resized\n");
1384 	error = -ENOMEM;
1385 	goto out;
1386 
1387  overflow:
1388 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1389 	sdev_printk(KERN_WARNING, scsidp,
1390 		    "Unable to attach sg device type=%d, minor "
1391 		    "number exceeds %d\n", scsidp->type, SG_MAX_DEVS - 1);
1392 	error = -ENODEV;
1393 	goto out;
1394 }
1395 
1396 static int
1397 sg_add(struct class_device *cl_dev, struct class_interface *cl_intf)
1398 {
1399 	struct scsi_device *scsidp = to_scsi_device(cl_dev->dev);
1400 	struct gendisk *disk;
1401 	Sg_device *sdp = NULL;
1402 	struct cdev * cdev = NULL;
1403 	int error, k;
1404 
1405 	disk = alloc_disk(1);
1406 	if (!disk) {
1407 		printk(KERN_WARNING "alloc_disk failed\n");
1408 		return -ENOMEM;
1409 	}
1410 	disk->major = SCSI_GENERIC_MAJOR;
1411 
1412 	error = -ENOMEM;
1413 	cdev = cdev_alloc();
1414 	if (!cdev) {
1415 		printk(KERN_WARNING "cdev_alloc failed\n");
1416 		goto out;
1417 	}
1418 	cdev->owner = THIS_MODULE;
1419 	cdev->ops = &sg_fops;
1420 
1421 	error = sg_alloc(disk, scsidp);
1422 	if (error < 0) {
1423 		printk(KERN_WARNING "sg_alloc failed\n");
1424 		goto out;
1425 	}
1426 	k = error;
1427 	sdp = sg_dev_arr[k];
1428 
1429 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, k), 1);
1430 	if (error)
1431 		goto out;
1432 
1433 	sdp->cdev = cdev;
1434 	if (sg_sysfs_valid) {
1435 		struct class_device * sg_class_member;
1436 
1437 		sg_class_member = class_device_create(sg_sysfs_class, NULL,
1438 				MKDEV(SCSI_GENERIC_MAJOR, k),
1439 				cl_dev->dev, "%s",
1440 				disk->disk_name);
1441 		if (IS_ERR(sg_class_member))
1442 			printk(KERN_WARNING "sg_add: "
1443 				"class_device_create failed\n");
1444 		class_set_devdata(sg_class_member, sdp);
1445 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1446 					  &sg_class_member->kobj, "generic");
1447 		if (error)
1448 			printk(KERN_ERR "sg_add: unable to make symlink "
1449 					"'generic' back to sg%d\n", k);
1450 	} else
1451 		printk(KERN_WARNING "sg_add: sg_sys INvalid\n");
1452 
1453 	sdev_printk(KERN_NOTICE, scsidp,
1454 		    "Attached scsi generic sg%d type %d\n", k,scsidp->type);
1455 
1456 	return 0;
1457 
1458 out:
1459 	put_disk(disk);
1460 	if (cdev)
1461 		cdev_del(cdev);
1462 	return error;
1463 }
1464 
1465 static void
1466 sg_remove(struct class_device *cl_dev, struct class_interface *cl_intf)
1467 {
1468 	struct scsi_device *scsidp = to_scsi_device(cl_dev->dev);
1469 	Sg_device *sdp = NULL;
1470 	unsigned long iflags;
1471 	Sg_fd *sfp;
1472 	Sg_fd *tsfp;
1473 	Sg_request *srp;
1474 	Sg_request *tsrp;
1475 	int k, delay;
1476 
1477 	if (NULL == sg_dev_arr)
1478 		return;
1479 	delay = 0;
1480 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
1481 	for (k = 0; k < sg_dev_max; k++) {
1482 		sdp = sg_dev_arr[k];
1483 		if ((NULL == sdp) || (sdp->device != scsidp))
1484 			continue;	/* dirty but lowers nesting */
1485 		if (sdp->headfp) {
1486 			sdp->detached = 1;
1487 			for (sfp = sdp->headfp; sfp; sfp = tsfp) {
1488 				tsfp = sfp->nextfp;
1489 				for (srp = sfp->headrp; srp; srp = tsrp) {
1490 					tsrp = srp->nextrp;
1491 					if (sfp->closed || (0 == sg_srp_done(srp, sfp)))
1492 						sg_finish_rem_req(srp);
1493 				}
1494 				if (sfp->closed) {
1495 					scsi_device_put(sdp->device);
1496 					__sg_remove_sfp(sdp, sfp);
1497 				} else {
1498 					delay = 1;
1499 					wake_up_interruptible(&sfp->read_wait);
1500 					kill_fasync(&sfp->async_qp, SIGPOLL,
1501 						    POLL_HUP);
1502 				}
1503 			}
1504 			SCSI_LOG_TIMEOUT(3, printk("sg_detach: dev=%d, dirty\n", k));
1505 			if (NULL == sdp->headfp) {
1506 				sg_dev_arr[k] = NULL;
1507 			}
1508 		} else {	/* nothing active, simple case */
1509 			SCSI_LOG_TIMEOUT(3, printk("sg_detach: dev=%d\n", k));
1510 			sg_dev_arr[k] = NULL;
1511 		}
1512 		sg_nr_dev--;
1513 		break;
1514 	}
1515 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
1516 
1517 	if (sdp) {
1518 		sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1519 		class_device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, k));
1520 		cdev_del(sdp->cdev);
1521 		sdp->cdev = NULL;
1522 		put_disk(sdp->disk);
1523 		sdp->disk = NULL;
1524 		if (NULL == sdp->headfp)
1525 			kfree((char *) sdp);
1526 	}
1527 
1528 	if (delay)
1529 		msleep(10);	/* dirty detach so delay device destruction */
1530 }
1531 
1532 /* Set 'perm' (4th argument) to 0 to disable module_param's definition
1533  * of sysfs parameters (which module_param doesn't yet support).
1534  * Sysfs parameters defined explicitly below.
1535  */
1536 module_param_named(def_reserved_size, def_reserved_size, int, S_IRUGO);
1537 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1538 
1539 MODULE_AUTHOR("Douglas Gilbert");
1540 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1541 MODULE_LICENSE("GPL");
1542 MODULE_VERSION(SG_VERSION_STR);
1543 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1544 
1545 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1546 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1547 
1548 static int __init
1549 init_sg(void)
1550 {
1551 	int rc;
1552 
1553 	if (def_reserved_size >= 0)
1554 		sg_big_buff = def_reserved_size;
1555 
1556 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1557 				    SG_MAX_DEVS, "sg");
1558 	if (rc)
1559 		return rc;
1560         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1561         if ( IS_ERR(sg_sysfs_class) ) {
1562 		rc = PTR_ERR(sg_sysfs_class);
1563 		goto err_out;
1564         }
1565 	sg_sysfs_valid = 1;
1566 	rc = scsi_register_interface(&sg_interface);
1567 	if (0 == rc) {
1568 #ifdef CONFIG_SCSI_PROC_FS
1569 		sg_proc_init();
1570 #endif				/* CONFIG_SCSI_PROC_FS */
1571 		return 0;
1572 	}
1573 	class_destroy(sg_sysfs_class);
1574 err_out:
1575 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1576 	return rc;
1577 }
1578 
1579 static void __exit
1580 exit_sg(void)
1581 {
1582 #ifdef CONFIG_SCSI_PROC_FS
1583 	sg_proc_cleanup();
1584 #endif				/* CONFIG_SCSI_PROC_FS */
1585 	scsi_unregister_interface(&sg_interface);
1586 	class_destroy(sg_sysfs_class);
1587 	sg_sysfs_valid = 0;
1588 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1589 				 SG_MAX_DEVS);
1590 	kfree((char *)sg_dev_arr);
1591 	sg_dev_arr = NULL;
1592 	sg_dev_max = 0;
1593 }
1594 
1595 static int
1596 sg_start_req(Sg_request * srp)
1597 {
1598 	int res;
1599 	Sg_fd *sfp = srp->parentfp;
1600 	sg_io_hdr_t *hp = &srp->header;
1601 	int dxfer_len = (int) hp->dxfer_len;
1602 	int dxfer_dir = hp->dxfer_direction;
1603 	Sg_scatter_hold *req_schp = &srp->data;
1604 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1605 
1606 	SCSI_LOG_TIMEOUT(4, printk("sg_start_req: dxfer_len=%d\n", dxfer_len));
1607 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1608 		return 0;
1609 	if (sg_allow_dio && (hp->flags & SG_FLAG_DIRECT_IO) &&
1610 	    (dxfer_dir != SG_DXFER_UNKNOWN) && (0 == hp->iovec_count) &&
1611 	    (!sfp->parentdp->device->host->unchecked_isa_dma)) {
1612 		res = sg_build_direct(srp, sfp, dxfer_len);
1613 		if (res <= 0)	/* -ve -> error, 0 -> done, 1 -> try indirect */
1614 			return res;
1615 	}
1616 	if ((!sg_res_in_use(sfp)) && (dxfer_len <= rsv_schp->bufflen))
1617 		sg_link_reserve(sfp, srp, dxfer_len);
1618 	else {
1619 		res = sg_build_indirect(req_schp, sfp, dxfer_len);
1620 		if (res) {
1621 			sg_remove_scat(req_schp);
1622 			return res;
1623 		}
1624 	}
1625 	return 0;
1626 }
1627 
1628 static void
1629 sg_finish_rem_req(Sg_request * srp)
1630 {
1631 	Sg_fd *sfp = srp->parentfp;
1632 	Sg_scatter_hold *req_schp = &srp->data;
1633 
1634 	SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
1635 	if (srp->res_used)
1636 		sg_unlink_reserve(sfp, srp);
1637 	else
1638 		sg_remove_scat(req_schp);
1639 	sg_remove_request(sfp, srp);
1640 }
1641 
1642 static int
1643 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1644 {
1645 	int sg_bufflen = tablesize * sizeof(struct scatterlist);
1646 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1647 
1648 	/*
1649 	 * TODO: test without low_dma, we should not need it since
1650 	 * the block layer will bounce the buffer for us
1651 	 *
1652 	 * XXX(hch): we shouldn't need GFP_DMA for the actual S/G list.
1653 	 */
1654 	if (sfp->low_dma)
1655 		 gfp_flags |= GFP_DMA;
1656 	schp->buffer = kzalloc(sg_bufflen, gfp_flags);
1657 	if (!schp->buffer)
1658 		return -ENOMEM;
1659 	schp->sglist_len = sg_bufflen;
1660 	return tablesize;	/* number of scat_gath elements allocated */
1661 }
1662 
1663 #ifdef SG_ALLOW_DIO_CODE
1664 /* vvvvvvvv  following code borrowed from st driver's direct IO vvvvvvvvv */
1665 	/* TODO: hopefully we can use the generic block layer code */
1666 
1667 /* Pin down user pages and put them into a scatter gather list. Returns <= 0 if
1668    - mapping of all pages not successful
1669    (i.e., either completely successful or fails)
1670 */
1671 static int
1672 st_map_user_pages(struct scatterlist *sgl, const unsigned int max_pages,
1673 	          unsigned long uaddr, size_t count, int rw)
1674 {
1675 	unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
1676 	unsigned long start = uaddr >> PAGE_SHIFT;
1677 	const int nr_pages = end - start;
1678 	int res, i, j;
1679 	struct page **pages;
1680 
1681 	/* User attempted Overflow! */
1682 	if ((uaddr + count) < uaddr)
1683 		return -EINVAL;
1684 
1685 	/* Too big */
1686         if (nr_pages > max_pages)
1687 		return -ENOMEM;
1688 
1689 	/* Hmm? */
1690 	if (count == 0)
1691 		return 0;
1692 
1693 	if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_ATOMIC)) == NULL)
1694 		return -ENOMEM;
1695 
1696         /* Try to fault in all of the necessary pages */
1697 	down_read(&current->mm->mmap_sem);
1698         /* rw==READ means read from drive, write into memory area */
1699 	res = get_user_pages(
1700 		current,
1701 		current->mm,
1702 		uaddr,
1703 		nr_pages,
1704 		rw == READ,
1705 		0, /* don't force */
1706 		pages,
1707 		NULL);
1708 	up_read(&current->mm->mmap_sem);
1709 
1710 	/* Errors and no page mapped should return here */
1711 	if (res < nr_pages)
1712 		goto out_unmap;
1713 
1714         for (i=0; i < nr_pages; i++) {
1715                 /* FIXME: flush superflous for rw==READ,
1716                  * probably wrong function for rw==WRITE
1717                  */
1718 		flush_dcache_page(pages[i]);
1719 		/* ?? Is locking needed? I don't think so */
1720 		/* if (TestSetPageLocked(pages[i]))
1721 		   goto out_unlock; */
1722         }
1723 
1724 	sgl[0].page = pages[0];
1725 	sgl[0].offset = uaddr & ~PAGE_MASK;
1726 	if (nr_pages > 1) {
1727 		sgl[0].length = PAGE_SIZE - sgl[0].offset;
1728 		count -= sgl[0].length;
1729 		for (i=1; i < nr_pages ; i++) {
1730 			sgl[i].page = pages[i];
1731 			sgl[i].length = count < PAGE_SIZE ? count : PAGE_SIZE;
1732 			count -= PAGE_SIZE;
1733 		}
1734 	}
1735 	else {
1736 		sgl[0].length = count;
1737 	}
1738 
1739 	kfree(pages);
1740 	return nr_pages;
1741 
1742  out_unmap:
1743 	if (res > 0) {
1744 		for (j=0; j < res; j++)
1745 			page_cache_release(pages[j]);
1746 		res = 0;
1747 	}
1748 	kfree(pages);
1749 	return res;
1750 }
1751 
1752 
1753 /* And unmap them... */
1754 static int
1755 st_unmap_user_pages(struct scatterlist *sgl, const unsigned int nr_pages,
1756 		    int dirtied)
1757 {
1758 	int i;
1759 
1760 	for (i=0; i < nr_pages; i++) {
1761 		struct page *page = sgl[i].page;
1762 
1763 		if (dirtied)
1764 			SetPageDirty(page);
1765 		/* unlock_page(page); */
1766 		/* FIXME: cache flush missing for rw==READ
1767 		 * FIXME: call the correct reference counting function
1768 		 */
1769 		page_cache_release(page);
1770 	}
1771 
1772 	return 0;
1773 }
1774 
1775 /* ^^^^^^^^  above code borrowed from st driver's direct IO ^^^^^^^^^ */
1776 #endif
1777 
1778 
1779 /* Returns: -ve -> error, 0 -> done, 1 -> try indirect */
1780 static int
1781 sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len)
1782 {
1783 #ifdef SG_ALLOW_DIO_CODE
1784 	sg_io_hdr_t *hp = &srp->header;
1785 	Sg_scatter_hold *schp = &srp->data;
1786 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1787 	int mx_sc_elems, res;
1788 	struct scsi_device *sdev = sfp->parentdp->device;
1789 
1790 	if (((unsigned long)hp->dxferp &
1791 			queue_dma_alignment(sdev->request_queue)) != 0)
1792 		return 1;
1793 
1794 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1795         if (mx_sc_elems <= 0) {
1796                 return 1;
1797         }
1798 	res = st_map_user_pages(schp->buffer, mx_sc_elems,
1799 				(unsigned long)hp->dxferp, dxfer_len,
1800 				(SG_DXFER_TO_DEV == hp->dxfer_direction) ? 1 : 0);
1801 	if (res <= 0)
1802 		return 1;
1803 	schp->k_use_sg = res;
1804 	schp->dio_in_use = 1;
1805 	hp->info |= SG_INFO_DIRECT_IO;
1806 	return 0;
1807 #else
1808 	return 1;
1809 #endif
1810 }
1811 
1812 static int
1813 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1814 {
1815 	struct scatterlist *sg;
1816 	int ret_sz = 0, k, rem_sz, num, mx_sc_elems;
1817 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1818 	int blk_size = buff_size;
1819 	struct page *p = NULL;
1820 
1821 	if ((blk_size < 0) || (!sfp))
1822 		return -EFAULT;
1823 	if (0 == blk_size)
1824 		++blk_size;	/* don't know why */
1825 /* round request up to next highest SG_SECTOR_SZ byte boundary */
1826 	blk_size = (blk_size + SG_SECTOR_MSK) & (~SG_SECTOR_MSK);
1827 	SCSI_LOG_TIMEOUT(4, printk("sg_build_indirect: buff_size=%d, blk_size=%d\n",
1828 				   buff_size, blk_size));
1829 
1830 	/* N.B. ret_sz carried into this block ... */
1831 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1832 	if (mx_sc_elems < 0)
1833 		return mx_sc_elems;	/* most likely -ENOMEM */
1834 
1835 	for (k = 0, sg = schp->buffer, rem_sz = blk_size;
1836 	     (rem_sz > 0) && (k < mx_sc_elems);
1837 	     ++k, rem_sz -= ret_sz, ++sg) {
1838 
1839 		num = (rem_sz > SG_SCATTER_SZ) ? SG_SCATTER_SZ : rem_sz;
1840 		p = sg_page_malloc(num, sfp->low_dma, &ret_sz);
1841 		if (!p)
1842 			return -ENOMEM;
1843 
1844 		sg->page = p;
1845 		sg->length = ret_sz;
1846 
1847 		SCSI_LOG_TIMEOUT(5, printk("sg_build_build: k=%d, a=0x%p, len=%d\n",
1848 				  k, p, ret_sz));
1849 	}		/* end of for loop */
1850 
1851 	schp->k_use_sg = k;
1852 	SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, rem_sz=%d\n", k, rem_sz));
1853 
1854 	schp->bufflen = blk_size;
1855 	if (rem_sz > 0)	/* must have failed */
1856 		return -ENOMEM;
1857 
1858 	return 0;
1859 }
1860 
1861 static int
1862 sg_write_xfer(Sg_request * srp)
1863 {
1864 	sg_io_hdr_t *hp = &srp->header;
1865 	Sg_scatter_hold *schp = &srp->data;
1866 	struct scatterlist *sg = schp->buffer;
1867 	int num_xfer = 0;
1868 	int j, k, onum, usglen, ksglen, res;
1869 	int iovec_count = (int) hp->iovec_count;
1870 	int dxfer_dir = hp->dxfer_direction;
1871 	unsigned char *p;
1872 	unsigned char __user *up;
1873 	int new_interface = ('\0' == hp->interface_id) ? 0 : 1;
1874 
1875 	if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_TO_DEV == dxfer_dir) ||
1876 	    (SG_DXFER_TO_FROM_DEV == dxfer_dir)) {
1877 		num_xfer = (int) (new_interface ? hp->dxfer_len : hp->flags);
1878 		if (schp->bufflen < num_xfer)
1879 			num_xfer = schp->bufflen;
1880 	}
1881 	if ((num_xfer <= 0) || (schp->dio_in_use) ||
1882 	    (new_interface
1883 	     && ((SG_FLAG_NO_DXFER | SG_FLAG_MMAP_IO) & hp->flags)))
1884 		return 0;
1885 
1886 	SCSI_LOG_TIMEOUT(4, printk("sg_write_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n",
1887 			  num_xfer, iovec_count, schp->k_use_sg));
1888 	if (iovec_count) {
1889 		onum = iovec_count;
1890 		if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum))
1891 			return -EFAULT;
1892 	} else
1893 		onum = 1;
1894 
1895 	ksglen = sg->length;
1896 	p = page_address(sg->page);
1897 	for (j = 0, k = 0; j < onum; ++j) {
1898 		res = sg_u_iovec(hp, iovec_count, j, 1, &usglen, &up);
1899 		if (res)
1900 			return res;
1901 
1902 		for (; p; ++sg, ksglen = sg->length,
1903 		     p = page_address(sg->page)) {
1904 			if (usglen <= 0)
1905 				break;
1906 			if (ksglen > usglen) {
1907 				if (usglen >= num_xfer) {
1908 					if (__copy_from_user(p, up, num_xfer))
1909 						return -EFAULT;
1910 					return 0;
1911 				}
1912 				if (__copy_from_user(p, up, usglen))
1913 					return -EFAULT;
1914 				p += usglen;
1915 				ksglen -= usglen;
1916 				break;
1917 			} else {
1918 				if (ksglen >= num_xfer) {
1919 					if (__copy_from_user(p, up, num_xfer))
1920 						return -EFAULT;
1921 					return 0;
1922 				}
1923 				if (__copy_from_user(p, up, ksglen))
1924 					return -EFAULT;
1925 				up += ksglen;
1926 				usglen -= ksglen;
1927 			}
1928 			++k;
1929 			if (k >= schp->k_use_sg)
1930 				return 0;
1931 		}
1932 	}
1933 
1934 	return 0;
1935 }
1936 
1937 static int
1938 sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind,
1939 	   int wr_xf, int *countp, unsigned char __user **up)
1940 {
1941 	int num_xfer = (int) hp->dxfer_len;
1942 	unsigned char __user *p = hp->dxferp;
1943 	int count;
1944 
1945 	if (0 == sg_num) {
1946 		if (wr_xf && ('\0' == hp->interface_id))
1947 			count = (int) hp->flags;	/* holds "old" input_size */
1948 		else
1949 			count = num_xfer;
1950 	} else {
1951 		sg_iovec_t iovec;
1952 		if (__copy_from_user(&iovec, p + ind*SZ_SG_IOVEC, SZ_SG_IOVEC))
1953 			return -EFAULT;
1954 		p = iovec.iov_base;
1955 		count = (int) iovec.iov_len;
1956 	}
1957 	if (!access_ok(wr_xf ? VERIFY_READ : VERIFY_WRITE, p, count))
1958 		return -EFAULT;
1959 	if (up)
1960 		*up = p;
1961 	if (countp)
1962 		*countp = count;
1963 	return 0;
1964 }
1965 
1966 static void
1967 sg_remove_scat(Sg_scatter_hold * schp)
1968 {
1969 	SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1970 	if (schp->buffer && (schp->sglist_len > 0)) {
1971 		struct scatterlist *sg = schp->buffer;
1972 
1973 		if (schp->dio_in_use) {
1974 #ifdef SG_ALLOW_DIO_CODE
1975 			st_unmap_user_pages(sg, schp->k_use_sg, TRUE);
1976 #endif
1977 		} else {
1978 			int k;
1979 
1980 			for (k = 0; (k < schp->k_use_sg) && sg->page;
1981 			     ++k, ++sg) {
1982 				SCSI_LOG_TIMEOUT(5, printk(
1983 				    "sg_remove_scat: k=%d, a=0x%p, len=%d\n",
1984 				    k, sg->page, sg->length));
1985 				sg_page_free(sg->page, sg->length);
1986 			}
1987 		}
1988 		kfree(schp->buffer);
1989 	}
1990 	memset(schp, 0, sizeof (*schp));
1991 }
1992 
1993 static int
1994 sg_read_xfer(Sg_request * srp)
1995 {
1996 	sg_io_hdr_t *hp = &srp->header;
1997 	Sg_scatter_hold *schp = &srp->data;
1998 	struct scatterlist *sg = schp->buffer;
1999 	int num_xfer = 0;
2000 	int j, k, onum, usglen, ksglen, res;
2001 	int iovec_count = (int) hp->iovec_count;
2002 	int dxfer_dir = hp->dxfer_direction;
2003 	unsigned char *p;
2004 	unsigned char __user *up;
2005 	int new_interface = ('\0' == hp->interface_id) ? 0 : 1;
2006 
2007 	if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_FROM_DEV == dxfer_dir)
2008 	    || (SG_DXFER_TO_FROM_DEV == dxfer_dir)) {
2009 		num_xfer = hp->dxfer_len;
2010 		if (schp->bufflen < num_xfer)
2011 			num_xfer = schp->bufflen;
2012 	}
2013 	if ((num_xfer <= 0) || (schp->dio_in_use) ||
2014 	    (new_interface
2015 	     && ((SG_FLAG_NO_DXFER | SG_FLAG_MMAP_IO) & hp->flags)))
2016 		return 0;
2017 
2018 	SCSI_LOG_TIMEOUT(4, printk("sg_read_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n",
2019 			  num_xfer, iovec_count, schp->k_use_sg));
2020 	if (iovec_count) {
2021 		onum = iovec_count;
2022 		if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum))
2023 			return -EFAULT;
2024 	} else
2025 		onum = 1;
2026 
2027 	p = page_address(sg->page);
2028 	ksglen = sg->length;
2029 	for (j = 0, k = 0; j < onum; ++j) {
2030 		res = sg_u_iovec(hp, iovec_count, j, 0, &usglen, &up);
2031 		if (res)
2032 			return res;
2033 
2034 		for (; p; ++sg, ksglen = sg->length,
2035 		     p = page_address(sg->page)) {
2036 			if (usglen <= 0)
2037 				break;
2038 			if (ksglen > usglen) {
2039 				if (usglen >= num_xfer) {
2040 					if (__copy_to_user(up, p, num_xfer))
2041 						return -EFAULT;
2042 					return 0;
2043 				}
2044 				if (__copy_to_user(up, p, usglen))
2045 					return -EFAULT;
2046 				p += usglen;
2047 				ksglen -= usglen;
2048 				break;
2049 			} else {
2050 				if (ksglen >= num_xfer) {
2051 					if (__copy_to_user(up, p, num_xfer))
2052 						return -EFAULT;
2053 					return 0;
2054 				}
2055 				if (__copy_to_user(up, p, ksglen))
2056 					return -EFAULT;
2057 				up += ksglen;
2058 				usglen -= ksglen;
2059 			}
2060 			++k;
2061 			if (k >= schp->k_use_sg)
2062 				return 0;
2063 		}
2064 	}
2065 
2066 	return 0;
2067 }
2068 
2069 static int
2070 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
2071 {
2072 	Sg_scatter_hold *schp = &srp->data;
2073 	struct scatterlist *sg = schp->buffer;
2074 	int k, num;
2075 
2076 	SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n",
2077 				   num_read_xfer));
2078 	if ((!outp) || (num_read_xfer <= 0))
2079 		return 0;
2080 
2081 	for (k = 0; (k < schp->k_use_sg) && sg->page; ++k, ++sg) {
2082 		num = sg->length;
2083 		if (num > num_read_xfer) {
2084 			if (__copy_to_user(outp, page_address(sg->page),
2085 					   num_read_xfer))
2086 				return -EFAULT;
2087 			break;
2088 		} else {
2089 			if (__copy_to_user(outp, page_address(sg->page),
2090 					   num))
2091 				return -EFAULT;
2092 			num_read_xfer -= num;
2093 			if (num_read_xfer <= 0)
2094 				break;
2095 			outp += num;
2096 		}
2097 	}
2098 
2099 	return 0;
2100 }
2101 
2102 static void
2103 sg_build_reserve(Sg_fd * sfp, int req_size)
2104 {
2105 	Sg_scatter_hold *schp = &sfp->reserve;
2106 
2107 	SCSI_LOG_TIMEOUT(4, printk("sg_build_reserve: req_size=%d\n", req_size));
2108 	do {
2109 		if (req_size < PAGE_SIZE)
2110 			req_size = PAGE_SIZE;
2111 		if (0 == sg_build_indirect(schp, sfp, req_size))
2112 			return;
2113 		else
2114 			sg_remove_scat(schp);
2115 		req_size >>= 1;	/* divide by 2 */
2116 	} while (req_size > (PAGE_SIZE / 2));
2117 }
2118 
2119 static void
2120 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
2121 {
2122 	Sg_scatter_hold *req_schp = &srp->data;
2123 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
2124 	struct scatterlist *sg = rsv_schp->buffer;
2125 	int k, num, rem;
2126 
2127 	srp->res_used = 1;
2128 	SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
2129 	rem = size;
2130 
2131 	for (k = 0; k < rsv_schp->k_use_sg; ++k, ++sg) {
2132 		num = sg->length;
2133 		if (rem <= num) {
2134 			sfp->save_scat_len = num;
2135 			sg->length = rem;
2136 			req_schp->k_use_sg = k + 1;
2137 			req_schp->sglist_len = rsv_schp->sglist_len;
2138 			req_schp->buffer = rsv_schp->buffer;
2139 
2140 			req_schp->bufflen = size;
2141 			req_schp->b_malloc_len = rsv_schp->b_malloc_len;
2142 			break;
2143 		} else
2144 			rem -= num;
2145 	}
2146 
2147 	if (k >= rsv_schp->k_use_sg)
2148 		SCSI_LOG_TIMEOUT(1, printk("sg_link_reserve: BAD size\n"));
2149 }
2150 
2151 static void
2152 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2153 {
2154 	Sg_scatter_hold *req_schp = &srp->data;
2155 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
2156 
2157 	SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n",
2158 				   (int) req_schp->k_use_sg));
2159 	if ((rsv_schp->k_use_sg > 0) && (req_schp->k_use_sg > 0)) {
2160 		struct scatterlist *sg = rsv_schp->buffer;
2161 
2162 		if (sfp->save_scat_len > 0)
2163 			(sg + (req_schp->k_use_sg - 1))->length =
2164 			    (unsigned) sfp->save_scat_len;
2165 		else
2166 			SCSI_LOG_TIMEOUT(1, printk ("sg_unlink_reserve: BAD save_scat_len\n"));
2167 	}
2168 	req_schp->k_use_sg = 0;
2169 	req_schp->bufflen = 0;
2170 	req_schp->buffer = NULL;
2171 	req_schp->sglist_len = 0;
2172 	sfp->save_scat_len = 0;
2173 	srp->res_used = 0;
2174 }
2175 
2176 static Sg_request *
2177 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2178 {
2179 	Sg_request *resp;
2180 	unsigned long iflags;
2181 
2182 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2183 	for (resp = sfp->headrp; resp; resp = resp->nextrp) {
2184 		/* look for requests that are ready + not SG_IO owned */
2185 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
2186 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2187 			resp->done = 2;	/* guard against other readers */
2188 			break;
2189 		}
2190 	}
2191 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2192 	return resp;
2193 }
2194 
2195 #ifdef CONFIG_SCSI_PROC_FS
2196 static Sg_request *
2197 sg_get_nth_request(Sg_fd * sfp, int nth)
2198 {
2199 	Sg_request *resp;
2200 	unsigned long iflags;
2201 	int k;
2202 
2203 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2204 	for (k = 0, resp = sfp->headrp; resp && (k < nth);
2205 	     ++k, resp = resp->nextrp) ;
2206 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2207 	return resp;
2208 }
2209 #endif
2210 
2211 /* always adds to end of list */
2212 static Sg_request *
2213 sg_add_request(Sg_fd * sfp)
2214 {
2215 	int k;
2216 	unsigned long iflags;
2217 	Sg_request *resp;
2218 	Sg_request *rp = sfp->req_arr;
2219 
2220 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2221 	resp = sfp->headrp;
2222 	if (!resp) {
2223 		memset(rp, 0, sizeof (Sg_request));
2224 		rp->parentfp = sfp;
2225 		resp = rp;
2226 		sfp->headrp = resp;
2227 	} else {
2228 		if (0 == sfp->cmd_q)
2229 			resp = NULL;	/* command queuing disallowed */
2230 		else {
2231 			for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2232 				if (!rp->parentfp)
2233 					break;
2234 			}
2235 			if (k < SG_MAX_QUEUE) {
2236 				memset(rp, 0, sizeof (Sg_request));
2237 				rp->parentfp = sfp;
2238 				while (resp->nextrp)
2239 					resp = resp->nextrp;
2240 				resp->nextrp = rp;
2241 				resp = rp;
2242 			} else
2243 				resp = NULL;
2244 		}
2245 	}
2246 	if (resp) {
2247 		resp->nextrp = NULL;
2248 		resp->header.duration = jiffies_to_msecs(jiffies);
2249 	}
2250 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2251 	return resp;
2252 }
2253 
2254 /* Return of 1 for found; 0 for not found */
2255 static int
2256 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2257 {
2258 	Sg_request *prev_rp;
2259 	Sg_request *rp;
2260 	unsigned long iflags;
2261 	int res = 0;
2262 
2263 	if ((!sfp) || (!srp) || (!sfp->headrp))
2264 		return res;
2265 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2266 	prev_rp = sfp->headrp;
2267 	if (srp == prev_rp) {
2268 		sfp->headrp = prev_rp->nextrp;
2269 		prev_rp->parentfp = NULL;
2270 		res = 1;
2271 	} else {
2272 		while ((rp = prev_rp->nextrp)) {
2273 			if (srp == rp) {
2274 				prev_rp->nextrp = rp->nextrp;
2275 				rp->parentfp = NULL;
2276 				res = 1;
2277 				break;
2278 			}
2279 			prev_rp = rp;
2280 		}
2281 	}
2282 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2283 	return res;
2284 }
2285 
2286 #ifdef CONFIG_SCSI_PROC_FS
2287 static Sg_fd *
2288 sg_get_nth_sfp(Sg_device * sdp, int nth)
2289 {
2290 	Sg_fd *resp;
2291 	unsigned long iflags;
2292 	int k;
2293 
2294 	read_lock_irqsave(&sg_dev_arr_lock, iflags);
2295 	for (k = 0, resp = sdp->headfp; resp && (k < nth);
2296 	     ++k, resp = resp->nextfp) ;
2297 	read_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2298 	return resp;
2299 }
2300 #endif
2301 
2302 static Sg_fd *
2303 sg_add_sfp(Sg_device * sdp, int dev)
2304 {
2305 	Sg_fd *sfp;
2306 	unsigned long iflags;
2307 
2308 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2309 	if (!sfp)
2310 		return NULL;
2311 
2312 	init_waitqueue_head(&sfp->read_wait);
2313 	rwlock_init(&sfp->rq_list_lock);
2314 
2315 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2316 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2317 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2318 	sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2319 	    sdp->device->host->unchecked_isa_dma : 1;
2320 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2321 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2322 	sfp->parentdp = sdp;
2323 	write_lock_irqsave(&sg_dev_arr_lock, iflags);
2324 	if (!sdp->headfp)
2325 		sdp->headfp = sfp;
2326 	else {			/* add to tail of existing list */
2327 		Sg_fd *pfp = sdp->headfp;
2328 		while (pfp->nextfp)
2329 			pfp = pfp->nextfp;
2330 		pfp->nextfp = sfp;
2331 	}
2332 	write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2333 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
2334 	sg_build_reserve(sfp, sg_big_buff);
2335 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp:   bufflen=%d, k_use_sg=%d\n",
2336 			   sfp->reserve.bufflen, sfp->reserve.k_use_sg));
2337 	return sfp;
2338 }
2339 
2340 static void
2341 __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2342 {
2343 	Sg_fd *fp;
2344 	Sg_fd *prev_fp;
2345 
2346 	prev_fp = sdp->headfp;
2347 	if (sfp == prev_fp)
2348 		sdp->headfp = prev_fp->nextfp;
2349 	else {
2350 		while ((fp = prev_fp->nextfp)) {
2351 			if (sfp == fp) {
2352 				prev_fp->nextfp = fp->nextfp;
2353 				break;
2354 			}
2355 			prev_fp = fp;
2356 		}
2357 	}
2358 	if (sfp->reserve.bufflen > 0) {
2359 		SCSI_LOG_TIMEOUT(6,
2360 			printk("__sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2361 			(int) sfp->reserve.bufflen, (int) sfp->reserve.k_use_sg));
2362 		sg_remove_scat(&sfp->reserve);
2363 	}
2364 	sfp->parentdp = NULL;
2365 	SCSI_LOG_TIMEOUT(6, printk("__sg_remove_sfp:    sfp=0x%p\n", sfp));
2366 	kfree(sfp);
2367 }
2368 
2369 /* Returns 0 in normal case, 1 when detached and sdp object removed */
2370 static int
2371 sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2372 {
2373 	Sg_request *srp;
2374 	Sg_request *tsrp;
2375 	int dirty = 0;
2376 	int res = 0;
2377 
2378 	for (srp = sfp->headrp; srp; srp = tsrp) {
2379 		tsrp = srp->nextrp;
2380 		if (sg_srp_done(srp, sfp))
2381 			sg_finish_rem_req(srp);
2382 		else
2383 			++dirty;
2384 	}
2385 	if (0 == dirty) {
2386 		unsigned long iflags;
2387 
2388 		write_lock_irqsave(&sg_dev_arr_lock, iflags);
2389 		__sg_remove_sfp(sdp, sfp);
2390 		if (sdp->detached && (NULL == sdp->headfp)) {
2391 			int k, maxd;
2392 
2393 			maxd = sg_dev_max;
2394 			for (k = 0; k < maxd; ++k) {
2395 				if (sdp == sg_dev_arr[k])
2396 					break;
2397 			}
2398 			if (k < maxd)
2399 				sg_dev_arr[k] = NULL;
2400 			kfree((char *) sdp);
2401 			res = 1;
2402 		}
2403 		write_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2404 	} else {
2405 		/* MOD_INC's to inhibit unloading sg and associated adapter driver */
2406 		/* only bump the access_count if we actually succeeded in
2407 		 * throwing another counter on the host module */
2408 		scsi_device_get(sdp->device);	/* XXX: retval ignored? */
2409 		sfp->closed = 1;	/* flag dirty state on this fd */
2410 		SCSI_LOG_TIMEOUT(1, printk("sg_remove_sfp: worrisome, %d writes pending\n",
2411 				  dirty));
2412 	}
2413 	return res;
2414 }
2415 
2416 static int
2417 sg_res_in_use(Sg_fd * sfp)
2418 {
2419 	const Sg_request *srp;
2420 	unsigned long iflags;
2421 
2422 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2423 	for (srp = sfp->headrp; srp; srp = srp->nextrp)
2424 		if (srp->res_used)
2425 			break;
2426 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2427 	return srp ? 1 : 0;
2428 }
2429 
2430 /* If retSzp==NULL want exact size or fail */
2431 static struct page *
2432 sg_page_malloc(int rqSz, int lowDma, int *retSzp)
2433 {
2434 	struct page *resp = NULL;
2435 	gfp_t page_mask;
2436 	int order, a_size;
2437 	int resSz = rqSz;
2438 
2439 	if (rqSz <= 0)
2440 		return resp;
2441 
2442 	if (lowDma)
2443 		page_mask = GFP_ATOMIC | GFP_DMA | __GFP_COMP | __GFP_NOWARN;
2444 	else
2445 		page_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
2446 
2447 	for (order = 0, a_size = PAGE_SIZE; a_size < rqSz;
2448 	     order++, a_size <<= 1) ;
2449 	resp = alloc_pages(page_mask, order);
2450 	while ((!resp) && order && retSzp) {
2451 		--order;
2452 		a_size >>= 1;	/* divide by 2, until PAGE_SIZE */
2453 		resp =  alloc_pages(page_mask, order);	/* try half */
2454 		resSz = a_size;
2455 	}
2456 	if (resp) {
2457 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2458 			memset(page_address(resp), 0, resSz);
2459 		if (retSzp)
2460 			*retSzp = resSz;
2461 	}
2462 	return resp;
2463 }
2464 
2465 static void
2466 sg_page_free(struct page *page, int size)
2467 {
2468 	int order, a_size;
2469 
2470 	if (!page)
2471 		return;
2472 	for (order = 0, a_size = PAGE_SIZE; a_size < size;
2473 	     order++, a_size <<= 1) ;
2474 	__free_pages(page, order);
2475 }
2476 
2477 #ifndef MAINTENANCE_IN_CMD
2478 #define MAINTENANCE_IN_CMD 0xa3
2479 #endif
2480 
2481 static unsigned char allow_ops[] = { TEST_UNIT_READY, REQUEST_SENSE,
2482 	INQUIRY, READ_CAPACITY, READ_BUFFER, READ_6, READ_10, READ_12,
2483 	READ_16, MODE_SENSE, MODE_SENSE_10, LOG_SENSE, REPORT_LUNS,
2484 	SERVICE_ACTION_IN, RECEIVE_DIAGNOSTIC, READ_LONG, MAINTENANCE_IN_CMD
2485 };
2486 
2487 static int
2488 sg_allow_access(unsigned char opcode, char dev_type)
2489 {
2490 	int k;
2491 
2492 	if (TYPE_SCANNER == dev_type)	/* TYPE_ROM maybe burner */
2493 		return 1;
2494 	for (k = 0; k < sizeof (allow_ops); ++k) {
2495 		if (opcode == allow_ops[k])
2496 			return 1;
2497 	}
2498 	return 0;
2499 }
2500 
2501 #ifdef CONFIG_SCSI_PROC_FS
2502 static int
2503 sg_last_dev(void)
2504 {
2505 	int k;
2506 	unsigned long iflags;
2507 
2508 	read_lock_irqsave(&sg_dev_arr_lock, iflags);
2509 	for (k = sg_dev_max - 1; k >= 0; --k)
2510 		if (sg_dev_arr[k] && sg_dev_arr[k]->device)
2511 			break;
2512 	read_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2513 	return k + 1;		/* origin 1 */
2514 }
2515 #endif
2516 
2517 static Sg_device *
2518 sg_get_dev(int dev)
2519 {
2520 	Sg_device *sdp = NULL;
2521 	unsigned long iflags;
2522 
2523 	if (sg_dev_arr && (dev >= 0)) {
2524 		read_lock_irqsave(&sg_dev_arr_lock, iflags);
2525 		if (dev < sg_dev_max)
2526 			sdp = sg_dev_arr[dev];
2527 		read_unlock_irqrestore(&sg_dev_arr_lock, iflags);
2528 	}
2529 	return sdp;
2530 }
2531 
2532 #ifdef CONFIG_SCSI_PROC_FS
2533 
2534 static struct proc_dir_entry *sg_proc_sgp = NULL;
2535 
2536 static char sg_proc_sg_dirname[] = "scsi/sg";
2537 
2538 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2539 
2540 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2541 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2542 			          size_t count, loff_t *off);
2543 static struct file_operations adio_fops = {
2544 	/* .owner, .read and .llseek added in sg_proc_init() */
2545 	.open = sg_proc_single_open_adio,
2546 	.write = sg_proc_write_adio,
2547 	.release = single_release,
2548 };
2549 
2550 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2551 static ssize_t sg_proc_write_dressz(struct file *filp,
2552 		const char __user *buffer, size_t count, loff_t *off);
2553 static struct file_operations dressz_fops = {
2554 	.open = sg_proc_single_open_dressz,
2555 	.write = sg_proc_write_dressz,
2556 	.release = single_release,
2557 };
2558 
2559 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2560 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2561 static struct file_operations version_fops = {
2562 	.open = sg_proc_single_open_version,
2563 	.release = single_release,
2564 };
2565 
2566 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2567 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2568 static struct file_operations devhdr_fops = {
2569 	.open = sg_proc_single_open_devhdr,
2570 	.release = single_release,
2571 };
2572 
2573 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2574 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2575 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2576 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2577 static void dev_seq_stop(struct seq_file *s, void *v);
2578 static struct file_operations dev_fops = {
2579 	.open = sg_proc_open_dev,
2580 	.release = seq_release,
2581 };
2582 static struct seq_operations dev_seq_ops = {
2583 	.start = dev_seq_start,
2584 	.next  = dev_seq_next,
2585 	.stop  = dev_seq_stop,
2586 	.show  = sg_proc_seq_show_dev,
2587 };
2588 
2589 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2590 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2591 static struct file_operations devstrs_fops = {
2592 	.open = sg_proc_open_devstrs,
2593 	.release = seq_release,
2594 };
2595 static struct seq_operations devstrs_seq_ops = {
2596 	.start = dev_seq_start,
2597 	.next  = dev_seq_next,
2598 	.stop  = dev_seq_stop,
2599 	.show  = sg_proc_seq_show_devstrs,
2600 };
2601 
2602 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2603 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2604 static struct file_operations debug_fops = {
2605 	.open = sg_proc_open_debug,
2606 	.release = seq_release,
2607 };
2608 static struct seq_operations debug_seq_ops = {
2609 	.start = dev_seq_start,
2610 	.next  = dev_seq_next,
2611 	.stop  = dev_seq_stop,
2612 	.show  = sg_proc_seq_show_debug,
2613 };
2614 
2615 
2616 struct sg_proc_leaf {
2617 	const char * name;
2618 	struct file_operations * fops;
2619 };
2620 
2621 static struct sg_proc_leaf sg_proc_leaf_arr[] = {
2622 	{"allow_dio", &adio_fops},
2623 	{"debug", &debug_fops},
2624 	{"def_reserved_size", &dressz_fops},
2625 	{"device_hdr", &devhdr_fops},
2626 	{"devices", &dev_fops},
2627 	{"device_strs", &devstrs_fops},
2628 	{"version", &version_fops}
2629 };
2630 
2631 static int
2632 sg_proc_init(void)
2633 {
2634 	int k, mask;
2635 	int num_leaves =
2636 	    sizeof (sg_proc_leaf_arr) / sizeof (sg_proc_leaf_arr[0]);
2637 	struct proc_dir_entry *pdep;
2638 	struct sg_proc_leaf * leaf;
2639 
2640 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2641 	if (!sg_proc_sgp)
2642 		return 1;
2643 	for (k = 0; k < num_leaves; ++k) {
2644 		leaf = &sg_proc_leaf_arr[k];
2645 		mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2646 		pdep = create_proc_entry(leaf->name, mask, sg_proc_sgp);
2647 		if (pdep) {
2648 			leaf->fops->owner = THIS_MODULE,
2649 			leaf->fops->read = seq_read,
2650 			leaf->fops->llseek = seq_lseek,
2651 			pdep->proc_fops = leaf->fops;
2652 		}
2653 	}
2654 	return 0;
2655 }
2656 
2657 static void
2658 sg_proc_cleanup(void)
2659 {
2660 	int k;
2661 	int num_leaves =
2662 	    sizeof (sg_proc_leaf_arr) / sizeof (sg_proc_leaf_arr[0]);
2663 
2664 	if (!sg_proc_sgp)
2665 		return;
2666 	for (k = 0; k < num_leaves; ++k)
2667 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2668 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2669 }
2670 
2671 
2672 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2673 {
2674 	seq_printf(s, "%d\n", *((int *)s->private));
2675 	return 0;
2676 }
2677 
2678 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2679 {
2680 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2681 }
2682 
2683 static ssize_t
2684 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2685 		   size_t count, loff_t *off)
2686 {
2687 	int num;
2688 	char buff[11];
2689 
2690 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2691 		return -EACCES;
2692 	num = (count < 10) ? count : 10;
2693 	if (copy_from_user(buff, buffer, num))
2694 		return -EFAULT;
2695 	buff[num] = '\0';
2696 	sg_allow_dio = simple_strtoul(buff, NULL, 10) ? 1 : 0;
2697 	return count;
2698 }
2699 
2700 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2701 {
2702 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2703 }
2704 
2705 static ssize_t
2706 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2707 		     size_t count, loff_t *off)
2708 {
2709 	int num;
2710 	unsigned long k = ULONG_MAX;
2711 	char buff[11];
2712 
2713 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2714 		return -EACCES;
2715 	num = (count < 10) ? count : 10;
2716 	if (copy_from_user(buff, buffer, num))
2717 		return -EFAULT;
2718 	buff[num] = '\0';
2719 	k = simple_strtoul(buff, NULL, 10);
2720 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2721 		sg_big_buff = k;
2722 		return count;
2723 	}
2724 	return -ERANGE;
2725 }
2726 
2727 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2728 {
2729 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2730 		   sg_version_date);
2731 	return 0;
2732 }
2733 
2734 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2735 {
2736 	return single_open(file, sg_proc_seq_show_version, NULL);
2737 }
2738 
2739 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2740 {
2741 	seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
2742 		   "online\n");
2743 	return 0;
2744 }
2745 
2746 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2747 {
2748 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2749 }
2750 
2751 struct sg_proc_deviter {
2752 	loff_t	index;
2753 	size_t	max;
2754 };
2755 
2756 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2757 {
2758 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2759 
2760 	s->private = it;
2761 	if (! it)
2762 		return NULL;
2763 
2764 	if (NULL == sg_dev_arr)
2765 		return NULL;
2766 	it->index = *pos;
2767 	it->max = sg_last_dev();
2768 	if (it->index >= it->max)
2769 		return NULL;
2770 	return it;
2771 }
2772 
2773 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2774 {
2775 	struct sg_proc_deviter * it = s->private;
2776 
2777 	*pos = ++it->index;
2778 	return (it->index < it->max) ? it : NULL;
2779 }
2780 
2781 static void dev_seq_stop(struct seq_file *s, void *v)
2782 {
2783 	kfree(s->private);
2784 }
2785 
2786 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2787 {
2788         return seq_open(file, &dev_seq_ops);
2789 }
2790 
2791 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2792 {
2793 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2794 	Sg_device *sdp;
2795 	struct scsi_device *scsidp;
2796 
2797 	sdp = it ? sg_get_dev(it->index) : NULL;
2798 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2799 		seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
2800 			      scsidp->host->host_no, scsidp->channel,
2801 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2802 			      1,
2803 			      (int) scsidp->queue_depth,
2804 			      (int) scsidp->device_busy,
2805 			      (int) scsi_device_online(scsidp));
2806 	else
2807 		seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2808 	return 0;
2809 }
2810 
2811 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2812 {
2813         return seq_open(file, &devstrs_seq_ops);
2814 }
2815 
2816 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2817 {
2818 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2819 	Sg_device *sdp;
2820 	struct scsi_device *scsidp;
2821 
2822 	sdp = it ? sg_get_dev(it->index) : NULL;
2823 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2824 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2825 			   scsidp->vendor, scsidp->model, scsidp->rev);
2826 	else
2827 		seq_printf(s, "<no active device>\n");
2828 	return 0;
2829 }
2830 
2831 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2832 {
2833 	int k, m, new_interface, blen, usg;
2834 	Sg_request *srp;
2835 	Sg_fd *fp;
2836 	const sg_io_hdr_t *hp;
2837 	const char * cp;
2838 	unsigned int ms;
2839 
2840 	for (k = 0; (fp = sg_get_nth_sfp(sdp, k)); ++k) {
2841 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2842 			   "(res)sgat=%d low_dma=%d\n", k + 1,
2843 			   jiffies_to_msecs(fp->timeout),
2844 			   fp->reserve.bufflen,
2845 			   (int) fp->reserve.k_use_sg,
2846 			   (int) fp->low_dma);
2847 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=%d\n",
2848 			   (int) fp->cmd_q, (int) fp->force_packid,
2849 			   (int) fp->keep_orphan, (int) fp->closed);
2850 		for (m = 0; (srp = sg_get_nth_request(fp, m)); ++m) {
2851 			hp = &srp->header;
2852 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2853 			if (srp->res_used) {
2854 				if (new_interface &&
2855 				    (SG_FLAG_MMAP_IO & hp->flags))
2856 					cp = "     mmap>> ";
2857 				else
2858 					cp = "     rb>> ";
2859 			} else {
2860 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2861 					cp = "     dio>> ";
2862 				else
2863 					cp = "     ";
2864 			}
2865 			seq_printf(s, cp);
2866 			blen = srp->data.bufflen;
2867 			usg = srp->data.k_use_sg;
2868 			seq_printf(s, srp->done ?
2869 				   ((1 == srp->done) ?  "rcv:" : "fin:")
2870 				   : "act:");
2871 			seq_printf(s, " id=%d blen=%d",
2872 				   srp->header.pack_id, blen);
2873 			if (srp->done)
2874 				seq_printf(s, " dur=%d", hp->duration);
2875 			else {
2876 				ms = jiffies_to_msecs(jiffies);
2877 				seq_printf(s, " t_o/elap=%d/%d",
2878 					(new_interface ? hp->timeout :
2879 						  jiffies_to_msecs(fp->timeout)),
2880 					(ms > hp->duration ? ms - hp->duration : 0));
2881 			}
2882 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2883 				   (int) srp->data.cmd_opcode);
2884 		}
2885 		if (0 == m)
2886 			seq_printf(s, "     No requests active\n");
2887 	}
2888 }
2889 
2890 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2891 {
2892         return seq_open(file, &debug_seq_ops);
2893 }
2894 
2895 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2896 {
2897 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2898 	Sg_device *sdp;
2899 
2900 	if (it && (0 == it->index)) {
2901 		seq_printf(s, "dev_max(currently)=%d max_active_device=%d "
2902 			   "(origin 1)\n", sg_dev_max, (int)it->max);
2903 		seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
2904 	}
2905 	sdp = it ? sg_get_dev(it->index) : NULL;
2906 	if (sdp) {
2907 		struct scsi_device *scsidp = sdp->device;
2908 
2909 		if (NULL == scsidp) {
2910 			seq_printf(s, "device %d detached ??\n",
2911 				   (int)it->index);
2912 			return 0;
2913 		}
2914 
2915 		if (sg_get_nth_sfp(sdp, 0)) {
2916 			seq_printf(s, " >>> device=%s ",
2917 				sdp->disk->disk_name);
2918 			if (sdp->detached)
2919 				seq_printf(s, "detached pending close ");
2920 			else
2921 				seq_printf
2922 				    (s, "scsi%d chan=%d id=%d lun=%d   em=%d",
2923 				     scsidp->host->host_no,
2924 				     scsidp->channel, scsidp->id,
2925 				     scsidp->lun,
2926 				     scsidp->host->hostt->emulated);
2927 			seq_printf(s, " sg_tablesize=%d excl=%d\n",
2928 				   sdp->sg_tablesize, sdp->exclude);
2929 		}
2930 		sg_proc_debug_helper(s, sdp);
2931 	}
2932 	return 0;
2933 }
2934 
2935 #endif				/* CONFIG_SCSI_PROC_FS */
2936 
2937 module_init(init_sg);
2938 module_exit(exit_sg);
2939