xref: /openbmc/linux/drivers/scsi/sg.c (revision 643d1f7f)
1 /*
2  *  History:
3  *  Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
4  *           to allow user process control of SCSI devices.
5  *  Development Sponsored by Killy Corp. NY NY
6  *
7  * Original driver (sg.c):
8  *        Copyright (C) 1992 Lawrence Foard
9  * Version 2 and 3 extensions to driver:
10  *        Copyright (C) 1998 - 2005 Douglas Gilbert
11  *
12  *  Modified  19-JAN-1998  Richard Gooch <rgooch@atnf.csiro.au>  Devfs support
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2, or (at your option)
17  * any later version.
18  *
19  */
20 
21 static int sg_version_num = 30534;	/* 2 digits for each component */
22 #define SG_VERSION_STR "3.5.34"
23 
24 /*
25  *  D. P. Gilbert (dgilbert@interlog.com, dougg@triode.net.au), notes:
26  *      - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
27  *        the kernel/module needs to be built with CONFIG_SCSI_LOGGING
28  *        (otherwise the macros compile to empty statements).
29  *
30  */
31 #include <linux/module.h>
32 
33 #include <linux/fs.h>
34 #include <linux/kernel.h>
35 #include <linux/sched.h>
36 #include <linux/string.h>
37 #include <linux/mm.h>
38 #include <linux/errno.h>
39 #include <linux/mtio.h>
40 #include <linux/ioctl.h>
41 #include <linux/fcntl.h>
42 #include <linux/init.h>
43 #include <linux/poll.h>
44 #include <linux/moduleparam.h>
45 #include <linux/cdev.h>
46 #include <linux/idr.h>
47 #include <linux/seq_file.h>
48 #include <linux/blkdev.h>
49 #include <linux/delay.h>
50 #include <linux/scatterlist.h>
51 #include <linux/blktrace_api.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 = "20061027";
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 static int scatter_elem_sz = SG_SCATTER_SZ;
99 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
100 
101 #define SG_SECTOR_SZ 512
102 #define SG_SECTOR_MSK (SG_SECTOR_SZ - 1)
103 
104 static int sg_add(struct class_device *, struct class_interface *);
105 static void sg_remove(struct class_device *, struct class_interface *);
106 
107 static DEFINE_IDR(sg_index_idr);
108 static DEFINE_RWLOCK(sg_index_lock);	/* Also used to lock
109 							   file descriptor list for device */
110 
111 static struct class_interface sg_interface = {
112 	.add		= sg_add,
113 	.remove		= sg_remove,
114 };
115 
116 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
117 	unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
118 	unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
119 	unsigned bufflen;	/* Size of (aggregate) data buffer */
120 	unsigned b_malloc_len;	/* actual len malloc'ed in buffer */
121 	struct scatterlist *buffer;/* scatter list */
122 	char dio_in_use;	/* 0->indirect IO (or mmap), 1->dio */
123 	unsigned char cmd_opcode; /* first byte of command */
124 } Sg_scatter_hold;
125 
126 struct sg_device;		/* forward declarations */
127 struct sg_fd;
128 
129 typedef struct sg_request {	/* SG_MAX_QUEUE requests outstanding per file */
130 	struct sg_request *nextrp;	/* NULL -> tail request (slist) */
131 	struct sg_fd *parentfp;	/* NULL -> not in use */
132 	Sg_scatter_hold data;	/* hold buffer, perhaps scatter list */
133 	sg_io_hdr_t header;	/* scsi command+info, see <scsi/sg.h> */
134 	unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
135 	char res_used;		/* 1 -> using reserve buffer, 0 -> not ... */
136 	char orphan;		/* 1 -> drop on sight, 0 -> normal */
137 	char sg_io_owned;	/* 1 -> packet belongs to SG_IO */
138 	volatile char done;	/* 0->before bh, 1->before read, 2->read */
139 } Sg_request;
140 
141 typedef struct sg_fd {		/* holds the state of a file descriptor */
142 	struct sg_fd *nextfp;	/* NULL when last opened fd on this device */
143 	struct sg_device *parentdp;	/* owning device */
144 	wait_queue_head_t read_wait;	/* queue read until command done */
145 	rwlock_t rq_list_lock;	/* protect access to list in req_arr */
146 	int timeout;		/* defaults to SG_DEFAULT_TIMEOUT      */
147 	int timeout_user;	/* defaults to SG_DEFAULT_TIMEOUT_USER */
148 	Sg_scatter_hold reserve;	/* buffer held for this file descriptor */
149 	unsigned save_scat_len;	/* original length of trunc. scat. element */
150 	Sg_request *headrp;	/* head of request slist, NULL->empty */
151 	struct fasync_struct *async_qp;	/* used by asynchronous notification */
152 	Sg_request req_arr[SG_MAX_QUEUE];	/* used as singly-linked list */
153 	char low_dma;		/* as in parent but possibly overridden to 1 */
154 	char force_packid;	/* 1 -> pack_id input to read(), 0 -> ignored */
155 	volatile char closed;	/* 1 -> fd closed but request(s) outstanding */
156 	char cmd_q;		/* 1 -> allow command queuing, 0 -> don't */
157 	char next_cmd_len;	/* 0 -> automatic (def), >0 -> use on next write() */
158 	char keep_orphan;	/* 0 -> drop orphan (def), 1 -> keep for read() */
159 	char mmap_called;	/* 0 -> mmap() never called on this fd */
160 } Sg_fd;
161 
162 typedef struct sg_device { /* holds the state of each scsi generic device */
163 	struct scsi_device *device;
164 	wait_queue_head_t o_excl_wait;	/* queue open() when O_EXCL in use */
165 	int sg_tablesize;	/* adapter's max scatter-gather table size */
166 	u32 index;		/* device index number */
167 	Sg_fd *headfp;		/* first open fd belonging to this device */
168 	volatile char detached;	/* 0->attached, 1->detached pending removal */
169 	volatile char exclude;	/* opened for exclusive access */
170 	char sgdebug;		/* 0->off, 1->sense, 9->dump dev, 10-> all devs */
171 	struct gendisk *disk;
172 	struct cdev * cdev;	/* char_dev [sysfs: /sys/cdev/major/sg<n>] */
173 } Sg_device;
174 
175 static int sg_fasync(int fd, struct file *filp, int mode);
176 /* tasklet or soft irq callback */
177 static void sg_cmd_done(void *data, char *sense, int result, int resid);
178 static int sg_start_req(Sg_request * srp);
179 static void sg_finish_rem_req(Sg_request * srp);
180 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
181 static int sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp,
182 			 int tablesize);
183 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
184 			   Sg_request * srp);
185 static ssize_t sg_new_write(Sg_fd * sfp, const char __user *buf, size_t count,
186 			    int blocking, int read_only, Sg_request ** o_srp);
187 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
188 			   unsigned char *cmnd, int timeout, int blocking);
189 static int sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind,
190 		      int wr_xf, int *countp, unsigned char __user **up);
191 static int sg_write_xfer(Sg_request * srp);
192 static int sg_read_xfer(Sg_request * srp);
193 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
194 static void sg_remove_scat(Sg_scatter_hold * schp);
195 static void sg_build_reserve(Sg_fd * sfp, int req_size);
196 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
197 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
198 static struct page *sg_page_malloc(int rqSz, int lowDma, int *retSzp);
199 static void sg_page_free(struct page *page, int size);
200 static Sg_fd *sg_add_sfp(Sg_device * sdp, int dev);
201 static int sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
202 static void __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
203 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
204 static Sg_request *sg_add_request(Sg_fd * sfp);
205 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
206 static int sg_res_in_use(Sg_fd * sfp);
207 static int sg_allow_access(unsigned char opcode, char dev_type);
208 static int sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len);
209 static Sg_device *sg_get_dev(int dev);
210 #ifdef CONFIG_SCSI_PROC_FS
211 static int sg_last_dev(void);
212 #endif
213 
214 #define SZ_SG_HEADER sizeof(struct sg_header)
215 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
216 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
217 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
218 
219 static int
220 sg_open(struct inode *inode, struct file *filp)
221 {
222 	int dev = iminor(inode);
223 	int flags = filp->f_flags;
224 	struct request_queue *q;
225 	Sg_device *sdp;
226 	Sg_fd *sfp;
227 	int res;
228 	int retval;
229 
230 	nonseekable_open(inode, filp);
231 	SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
232 	sdp = sg_get_dev(dev);
233 	if ((!sdp) || (!sdp->device))
234 		return -ENXIO;
235 	if (sdp->detached)
236 		return -ENODEV;
237 
238 	/* This driver's module count bumped by fops_get in <linux/fs.h> */
239 	/* Prevent the device driver from vanishing while we sleep */
240 	retval = scsi_device_get(sdp->device);
241 	if (retval)
242 		return retval;
243 
244 	if (!((flags & O_NONBLOCK) ||
245 	      scsi_block_when_processing_errors(sdp->device))) {
246 		retval = -ENXIO;
247 		/* we are in error recovery for this device */
248 		goto error_out;
249 	}
250 
251 	if (flags & O_EXCL) {
252 		if (O_RDONLY == (flags & O_ACCMODE)) {
253 			retval = -EPERM; /* Can't lock it with read only access */
254 			goto error_out;
255 		}
256 		if (sdp->headfp && (flags & O_NONBLOCK)) {
257 			retval = -EBUSY;
258 			goto error_out;
259 		}
260 		res = 0;
261 		__wait_event_interruptible(sdp->o_excl_wait,
262 			((sdp->headfp || sdp->exclude) ? 0 : (sdp->exclude = 1)), res);
263 		if (res) {
264 			retval = res;	/* -ERESTARTSYS because signal hit process */
265 			goto error_out;
266 		}
267 	} else if (sdp->exclude) {	/* some other fd has an exclusive lock on dev */
268 		if (flags & O_NONBLOCK) {
269 			retval = -EBUSY;
270 			goto error_out;
271 		}
272 		res = 0;
273 		__wait_event_interruptible(sdp->o_excl_wait, (!sdp->exclude),
274 					   res);
275 		if (res) {
276 			retval = res;	/* -ERESTARTSYS because signal hit process */
277 			goto error_out;
278 		}
279 	}
280 	if (sdp->detached) {
281 		retval = -ENODEV;
282 		goto error_out;
283 	}
284 	if (!sdp->headfp) {	/* no existing opens on this device */
285 		sdp->sgdebug = 0;
286 		q = sdp->device->request_queue;
287 		sdp->sg_tablesize = min(q->max_hw_segments,
288 					q->max_phys_segments);
289 	}
290 	if ((sfp = sg_add_sfp(sdp, dev)))
291 		filp->private_data = sfp;
292 	else {
293 		if (flags & O_EXCL)
294 			sdp->exclude = 0;	/* undo if error */
295 		retval = -ENOMEM;
296 		goto error_out;
297 	}
298 	return 0;
299 
300       error_out:
301 	scsi_device_put(sdp->device);
302 	return retval;
303 }
304 
305 /* Following function was formerly called 'sg_close' */
306 static int
307 sg_release(struct inode *inode, struct file *filp)
308 {
309 	Sg_device *sdp;
310 	Sg_fd *sfp;
311 
312 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
313 		return -ENXIO;
314 	SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
315 	sg_fasync(-1, filp, 0);	/* remove filp from async notification list */
316 	if (0 == sg_remove_sfp(sdp, sfp)) {	/* Returns 1 when sdp gone */
317 		if (!sdp->detached) {
318 			scsi_device_put(sdp->device);
319 		}
320 		sdp->exclude = 0;
321 		wake_up_interruptible(&sdp->o_excl_wait);
322 	}
323 	return 0;
324 }
325 
326 static ssize_t
327 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
328 {
329 	Sg_device *sdp;
330 	Sg_fd *sfp;
331 	Sg_request *srp;
332 	int req_pack_id = -1;
333 	sg_io_hdr_t *hp;
334 	struct sg_header *old_hdr = NULL;
335 	int retval = 0;
336 
337 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
338 		return -ENXIO;
339 	SCSI_LOG_TIMEOUT(3, printk("sg_read: %s, count=%d\n",
340 				   sdp->disk->disk_name, (int) count));
341 
342 	if (!access_ok(VERIFY_WRITE, buf, count))
343 		return -EFAULT;
344 	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
345 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
346 		if (!old_hdr)
347 			return -ENOMEM;
348 		if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
349 			retval = -EFAULT;
350 			goto free_old_hdr;
351 		}
352 		if (old_hdr->reply_len < 0) {
353 			if (count >= SZ_SG_IO_HDR) {
354 				sg_io_hdr_t *new_hdr;
355 				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
356 				if (!new_hdr) {
357 					retval = -ENOMEM;
358 					goto free_old_hdr;
359 				}
360 				retval =__copy_from_user
361 				    (new_hdr, buf, SZ_SG_IO_HDR);
362 				req_pack_id = new_hdr->pack_id;
363 				kfree(new_hdr);
364 				if (retval) {
365 					retval = -EFAULT;
366 					goto free_old_hdr;
367 				}
368 			}
369 		} else
370 			req_pack_id = old_hdr->pack_id;
371 	}
372 	srp = sg_get_rq_mark(sfp, req_pack_id);
373 	if (!srp) {		/* now wait on packet to arrive */
374 		if (sdp->detached) {
375 			retval = -ENODEV;
376 			goto free_old_hdr;
377 		}
378 		if (filp->f_flags & O_NONBLOCK) {
379 			retval = -EAGAIN;
380 			goto free_old_hdr;
381 		}
382 		while (1) {
383 			retval = 0; /* following macro beats race condition */
384 			__wait_event_interruptible(sfp->read_wait,
385 				(sdp->detached ||
386 				(srp = sg_get_rq_mark(sfp, req_pack_id))),
387 				retval);
388 			if (sdp->detached) {
389 				retval = -ENODEV;
390 				goto free_old_hdr;
391 			}
392 			if (0 == retval)
393 				break;
394 
395 			/* -ERESTARTSYS as signal hit process */
396 			goto free_old_hdr;
397 		}
398 	}
399 	if (srp->header.interface_id != '\0') {
400 		retval = sg_new_read(sfp, buf, count, srp);
401 		goto free_old_hdr;
402 	}
403 
404 	hp = &srp->header;
405 	if (old_hdr == NULL) {
406 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
407 		if (! old_hdr) {
408 			retval = -ENOMEM;
409 			goto free_old_hdr;
410 		}
411 	}
412 	memset(old_hdr, 0, SZ_SG_HEADER);
413 	old_hdr->reply_len = (int) hp->timeout;
414 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
415 	old_hdr->pack_id = hp->pack_id;
416 	old_hdr->twelve_byte =
417 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
418 	old_hdr->target_status = hp->masked_status;
419 	old_hdr->host_status = hp->host_status;
420 	old_hdr->driver_status = hp->driver_status;
421 	if ((CHECK_CONDITION & hp->masked_status) ||
422 	    (DRIVER_SENSE & hp->driver_status))
423 		memcpy(old_hdr->sense_buffer, srp->sense_b,
424 		       sizeof (old_hdr->sense_buffer));
425 	switch (hp->host_status) {
426 	/* This setup of 'result' is for backward compatibility and is best
427 	   ignored by the user who should use target, host + driver status */
428 	case DID_OK:
429 	case DID_PASSTHROUGH:
430 	case DID_SOFT_ERROR:
431 		old_hdr->result = 0;
432 		break;
433 	case DID_NO_CONNECT:
434 	case DID_BUS_BUSY:
435 	case DID_TIME_OUT:
436 		old_hdr->result = EBUSY;
437 		break;
438 	case DID_BAD_TARGET:
439 	case DID_ABORT:
440 	case DID_PARITY:
441 	case DID_RESET:
442 	case DID_BAD_INTR:
443 		old_hdr->result = EIO;
444 		break;
445 	case DID_ERROR:
446 		old_hdr->result = (srp->sense_b[0] == 0 &&
447 				  hp->masked_status == GOOD) ? 0 : EIO;
448 		break;
449 	default:
450 		old_hdr->result = EIO;
451 		break;
452 	}
453 
454 	/* Now copy the result back to the user buffer.  */
455 	if (count >= SZ_SG_HEADER) {
456 		if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
457 			retval = -EFAULT;
458 			goto free_old_hdr;
459 		}
460 		buf += SZ_SG_HEADER;
461 		if (count > old_hdr->reply_len)
462 			count = old_hdr->reply_len;
463 		if (count > SZ_SG_HEADER) {
464 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
465 				retval = -EFAULT;
466 				goto free_old_hdr;
467 			}
468 		}
469 	} else
470 		count = (old_hdr->result == 0) ? 0 : -EIO;
471 	sg_finish_rem_req(srp);
472 	retval = count;
473 free_old_hdr:
474 	kfree(old_hdr);
475 	return retval;
476 }
477 
478 static ssize_t
479 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
480 {
481 	sg_io_hdr_t *hp = &srp->header;
482 	int err = 0;
483 	int len;
484 
485 	if (count < SZ_SG_IO_HDR) {
486 		err = -EINVAL;
487 		goto err_out;
488 	}
489 	hp->sb_len_wr = 0;
490 	if ((hp->mx_sb_len > 0) && hp->sbp) {
491 		if ((CHECK_CONDITION & hp->masked_status) ||
492 		    (DRIVER_SENSE & hp->driver_status)) {
493 			int sb_len = SCSI_SENSE_BUFFERSIZE;
494 			sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
495 			len = 8 + (int) srp->sense_b[7];	/* Additional sense length field */
496 			len = (len > sb_len) ? sb_len : len;
497 			if (copy_to_user(hp->sbp, srp->sense_b, len)) {
498 				err = -EFAULT;
499 				goto err_out;
500 			}
501 			hp->sb_len_wr = len;
502 		}
503 	}
504 	if (hp->masked_status || hp->host_status || hp->driver_status)
505 		hp->info |= SG_INFO_CHECK;
506 	if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
507 		err = -EFAULT;
508 		goto err_out;
509 	}
510 	err = sg_read_xfer(srp);
511       err_out:
512 	sg_finish_rem_req(srp);
513 	return (0 == err) ? count : err;
514 }
515 
516 static ssize_t
517 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
518 {
519 	int mxsize, cmd_size, k;
520 	int input_size, blocking;
521 	unsigned char opcode;
522 	Sg_device *sdp;
523 	Sg_fd *sfp;
524 	Sg_request *srp;
525 	struct sg_header old_hdr;
526 	sg_io_hdr_t *hp;
527 	unsigned char cmnd[MAX_COMMAND_SIZE];
528 
529 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
530 		return -ENXIO;
531 	SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n",
532 				   sdp->disk->disk_name, (int) count));
533 	if (sdp->detached)
534 		return -ENODEV;
535 	if (!((filp->f_flags & O_NONBLOCK) ||
536 	      scsi_block_when_processing_errors(sdp->device)))
537 		return -ENXIO;
538 
539 	if (!access_ok(VERIFY_READ, buf, count))
540 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
541 	if (count < SZ_SG_HEADER)
542 		return -EIO;
543 	if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
544 		return -EFAULT;
545 	blocking = !(filp->f_flags & O_NONBLOCK);
546 	if (old_hdr.reply_len < 0)
547 		return sg_new_write(sfp, buf, count, blocking, 0, NULL);
548 	if (count < (SZ_SG_HEADER + 6))
549 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
550 
551 	if (!(srp = sg_add_request(sfp))) {
552 		SCSI_LOG_TIMEOUT(1, printk("sg_write: queue full\n"));
553 		return -EDOM;
554 	}
555 	buf += SZ_SG_HEADER;
556 	__get_user(opcode, buf);
557 	if (sfp->next_cmd_len > 0) {
558 		if (sfp->next_cmd_len > MAX_COMMAND_SIZE) {
559 			SCSI_LOG_TIMEOUT(1, printk("sg_write: command length too long\n"));
560 			sfp->next_cmd_len = 0;
561 			sg_remove_request(sfp, srp);
562 			return -EIO;
563 		}
564 		cmd_size = sfp->next_cmd_len;
565 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
566 	} else {
567 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
568 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
569 			cmd_size = 12;
570 	}
571 	SCSI_LOG_TIMEOUT(4, printk(
572 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
573 /* Determine buffer size.  */
574 	input_size = count - cmd_size;
575 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
576 	mxsize -= SZ_SG_HEADER;
577 	input_size -= SZ_SG_HEADER;
578 	if (input_size < 0) {
579 		sg_remove_request(sfp, srp);
580 		return -EIO;	/* User did not pass enough bytes for this command. */
581 	}
582 	hp = &srp->header;
583 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
584 	hp->cmd_len = (unsigned char) cmd_size;
585 	hp->iovec_count = 0;
586 	hp->mx_sb_len = 0;
587 	if (input_size > 0)
588 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
589 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
590 	else
591 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
592 	hp->dxfer_len = mxsize;
593 	hp->dxferp = (char __user *)buf + cmd_size;
594 	hp->sbp = NULL;
595 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
596 	hp->flags = input_size;	/* structure abuse ... */
597 	hp->pack_id = old_hdr.pack_id;
598 	hp->usr_ptr = NULL;
599 	if (__copy_from_user(cmnd, buf, cmd_size))
600 		return -EFAULT;
601 	/*
602 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
603 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
604 	 * is a non-zero input_size, so emit a warning.
605 	 */
606 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
607 		static char cmd[TASK_COMM_LEN];
608 		if (strcmp(current->comm, cmd) && 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 			strcpy(cmd, current->comm);
617 		}
618 	}
619 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
620 	return (k < 0) ? k : count;
621 }
622 
623 static ssize_t
624 sg_new_write(Sg_fd * sfp, const char __user *buf, size_t count,
625 	     int blocking, int read_only, Sg_request ** o_srp)
626 {
627 	int k;
628 	Sg_request *srp;
629 	sg_io_hdr_t *hp;
630 	unsigned char cmnd[MAX_COMMAND_SIZE];
631 	int timeout;
632 	unsigned long ul_timeout;
633 
634 	if (count < SZ_SG_IO_HDR)
635 		return -EINVAL;
636 	if (!access_ok(VERIFY_READ, buf, count))
637 		return -EFAULT; /* protects following copy_from_user()s + get_user()s */
638 
639 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
640 	if (!(srp = sg_add_request(sfp))) {
641 		SCSI_LOG_TIMEOUT(1, printk("sg_new_write: queue full\n"));
642 		return -EDOM;
643 	}
644 	hp = &srp->header;
645 	if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
646 		sg_remove_request(sfp, srp);
647 		return -EFAULT;
648 	}
649 	if (hp->interface_id != 'S') {
650 		sg_remove_request(sfp, srp);
651 		return -ENOSYS;
652 	}
653 	if (hp->flags & SG_FLAG_MMAP_IO) {
654 		if (hp->dxfer_len > sfp->reserve.bufflen) {
655 			sg_remove_request(sfp, srp);
656 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
657 		}
658 		if (hp->flags & SG_FLAG_DIRECT_IO) {
659 			sg_remove_request(sfp, srp);
660 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
661 		}
662 		if (sg_res_in_use(sfp)) {
663 			sg_remove_request(sfp, srp);
664 			return -EBUSY;	/* reserve buffer already being used */
665 		}
666 	}
667 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
668 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
669 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
670 		sg_remove_request(sfp, srp);
671 		return -EMSGSIZE;
672 	}
673 	if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
674 		sg_remove_request(sfp, srp);
675 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
676 	}
677 	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
678 		sg_remove_request(sfp, srp);
679 		return -EFAULT;
680 	}
681 	if (read_only &&
682 	    (!sg_allow_access(cmnd[0], sfp->parentdp->device->type))) {
683 		sg_remove_request(sfp, srp);
684 		return -EPERM;
685 	}
686 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
687 	if (k < 0)
688 		return k;
689 	if (o_srp)
690 		*o_srp = srp;
691 	return count;
692 }
693 
694 static int
695 sg_common_write(Sg_fd * sfp, Sg_request * srp,
696 		unsigned char *cmnd, int timeout, int blocking)
697 {
698 	int k, data_dir;
699 	Sg_device *sdp = sfp->parentdp;
700 	sg_io_hdr_t *hp = &srp->header;
701 
702 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
703 	hp->status = 0;
704 	hp->masked_status = 0;
705 	hp->msg_status = 0;
706 	hp->info = 0;
707 	hp->host_status = 0;
708 	hp->driver_status = 0;
709 	hp->resid = 0;
710 	SCSI_LOG_TIMEOUT(4, printk("sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
711 			  (int) cmnd[0], (int) hp->cmd_len));
712 
713 	if ((k = sg_start_req(srp))) {
714 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: start_req err=%d\n", k));
715 		sg_finish_rem_req(srp);
716 		return k;	/* probably out of space --> ENOMEM */
717 	}
718 	if ((k = sg_write_xfer(srp))) {
719 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: write_xfer, bad address\n"));
720 		sg_finish_rem_req(srp);
721 		return k;
722 	}
723 	if (sdp->detached) {
724 		sg_finish_rem_req(srp);
725 		return -ENODEV;
726 	}
727 
728 	switch (hp->dxfer_direction) {
729 	case SG_DXFER_TO_FROM_DEV:
730 	case SG_DXFER_FROM_DEV:
731 		data_dir = DMA_FROM_DEVICE;
732 		break;
733 	case SG_DXFER_TO_DEV:
734 		data_dir = DMA_TO_DEVICE;
735 		break;
736 	case SG_DXFER_UNKNOWN:
737 		data_dir = DMA_BIDIRECTIONAL;
738 		break;
739 	default:
740 		data_dir = DMA_NONE;
741 		break;
742 	}
743 	hp->duration = jiffies_to_msecs(jiffies);
744 /* Now send everything of to mid-level. The next time we hear about this
745    packet is when sg_cmd_done() is called (i.e. a callback). */
746 	if (scsi_execute_async(sdp->device, cmnd, hp->cmd_len, data_dir, srp->data.buffer,
747 				hp->dxfer_len, srp->data.k_use_sg, timeout,
748 				SG_DEFAULT_RETRIES, srp, sg_cmd_done,
749 				GFP_ATOMIC)) {
750 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: scsi_execute_async failed\n"));
751 		/*
752 		 * most likely out of mem, but could also be a bad map
753 		 */
754 		sg_finish_rem_req(srp);
755 		return -ENOMEM;
756 	} else
757 		return 0;
758 }
759 
760 static int
761 sg_srp_done(Sg_request *srp, Sg_fd *sfp)
762 {
763 	unsigned long iflags;
764 	int done;
765 
766 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
767 	done = srp->done;
768 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
769 	return done;
770 }
771 
772 static int
773 sg_ioctl(struct inode *inode, struct file *filp,
774 	 unsigned int cmd_in, unsigned long arg)
775 {
776 	void __user *p = (void __user *)arg;
777 	int __user *ip = p;
778 	int result, val, read_only;
779 	Sg_device *sdp;
780 	Sg_fd *sfp;
781 	Sg_request *srp;
782 	unsigned long iflags;
783 
784 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
785 		return -ENXIO;
786 	SCSI_LOG_TIMEOUT(3, printk("sg_ioctl: %s, cmd=0x%x\n",
787 				   sdp->disk->disk_name, (int) cmd_in));
788 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
789 
790 	switch (cmd_in) {
791 	case SG_IO:
792 		{
793 			int blocking = 1;	/* ignore O_NONBLOCK flag */
794 
795 			if (sdp->detached)
796 				return -ENODEV;
797 			if (!scsi_block_when_processing_errors(sdp->device))
798 				return -ENXIO;
799 			if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
800 				return -EFAULT;
801 			result =
802 			    sg_new_write(sfp, p, SZ_SG_IO_HDR,
803 					 blocking, read_only, &srp);
804 			if (result < 0)
805 				return result;
806 			srp->sg_io_owned = 1;
807 			while (1) {
808 				result = 0;	/* following macro to beat race condition */
809 				__wait_event_interruptible(sfp->read_wait,
810 					(sdp->detached || sfp->closed || sg_srp_done(srp, sfp)),
811 							   result);
812 				if (sdp->detached)
813 					return -ENODEV;
814 				if (sfp->closed)
815 					return 0;	/* request packet dropped already */
816 				if (0 == result)
817 					break;
818 				srp->orphan = 1;
819 				return result;	/* -ERESTARTSYS because signal hit process */
820 			}
821 			write_lock_irqsave(&sfp->rq_list_lock, iflags);
822 			srp->done = 2;
823 			write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
824 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
825 			return (result < 0) ? result : 0;
826 		}
827 	case SG_SET_TIMEOUT:
828 		result = get_user(val, ip);
829 		if (result)
830 			return result;
831 		if (val < 0)
832 			return -EIO;
833 		if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
834 		    val = MULDIV (INT_MAX, USER_HZ, HZ);
835 		sfp->timeout_user = val;
836 		sfp->timeout = MULDIV (val, HZ, USER_HZ);
837 
838 		return 0;
839 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
840 				/* strange ..., for backward compatibility */
841 		return sfp->timeout_user;
842 	case SG_SET_FORCE_LOW_DMA:
843 		result = get_user(val, ip);
844 		if (result)
845 			return result;
846 		if (val) {
847 			sfp->low_dma = 1;
848 			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
849 				val = (int) sfp->reserve.bufflen;
850 				sg_remove_scat(&sfp->reserve);
851 				sg_build_reserve(sfp, val);
852 			}
853 		} else {
854 			if (sdp->detached)
855 				return -ENODEV;
856 			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
857 		}
858 		return 0;
859 	case SG_GET_LOW_DMA:
860 		return put_user((int) sfp->low_dma, ip);
861 	case SG_GET_SCSI_ID:
862 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
863 			return -EFAULT;
864 		else {
865 			sg_scsi_id_t __user *sg_idp = p;
866 
867 			if (sdp->detached)
868 				return -ENODEV;
869 			__put_user((int) sdp->device->host->host_no,
870 				   &sg_idp->host_no);
871 			__put_user((int) sdp->device->channel,
872 				   &sg_idp->channel);
873 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
874 			__put_user((int) sdp->device->lun, &sg_idp->lun);
875 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
876 			__put_user((short) sdp->device->host->cmd_per_lun,
877 				   &sg_idp->h_cmd_per_lun);
878 			__put_user((short) sdp->device->queue_depth,
879 				   &sg_idp->d_queue_depth);
880 			__put_user(0, &sg_idp->unused[0]);
881 			__put_user(0, &sg_idp->unused[1]);
882 			return 0;
883 		}
884 	case SG_SET_FORCE_PACK_ID:
885 		result = get_user(val, ip);
886 		if (result)
887 			return result;
888 		sfp->force_packid = val ? 1 : 0;
889 		return 0;
890 	case SG_GET_PACK_ID:
891 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
892 			return -EFAULT;
893 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
894 		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
895 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
896 				read_unlock_irqrestore(&sfp->rq_list_lock,
897 						       iflags);
898 				__put_user(srp->header.pack_id, ip);
899 				return 0;
900 			}
901 		}
902 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
903 		__put_user(-1, ip);
904 		return 0;
905 	case SG_GET_NUM_WAITING:
906 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
907 		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
908 			if ((1 == srp->done) && (!srp->sg_io_owned))
909 				++val;
910 		}
911 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
912 		return put_user(val, ip);
913 	case SG_GET_SG_TABLESIZE:
914 		return put_user(sdp->sg_tablesize, ip);
915 	case SG_SET_RESERVED_SIZE:
916 		result = get_user(val, ip);
917 		if (result)
918 			return result;
919                 if (val < 0)
920                         return -EINVAL;
921 		val = min_t(int, val,
922 				sdp->device->request_queue->max_sectors * 512);
923 		if (val != sfp->reserve.bufflen) {
924 			if (sg_res_in_use(sfp) || sfp->mmap_called)
925 				return -EBUSY;
926 			sg_remove_scat(&sfp->reserve);
927 			sg_build_reserve(sfp, val);
928 		}
929 		return 0;
930 	case SG_GET_RESERVED_SIZE:
931 		val = min_t(int, sfp->reserve.bufflen,
932 				sdp->device->request_queue->max_sectors * 512);
933 		return put_user(val, ip);
934 	case SG_SET_COMMAND_Q:
935 		result = get_user(val, ip);
936 		if (result)
937 			return result;
938 		sfp->cmd_q = val ? 1 : 0;
939 		return 0;
940 	case SG_GET_COMMAND_Q:
941 		return put_user((int) sfp->cmd_q, ip);
942 	case SG_SET_KEEP_ORPHAN:
943 		result = get_user(val, ip);
944 		if (result)
945 			return result;
946 		sfp->keep_orphan = val;
947 		return 0;
948 	case SG_GET_KEEP_ORPHAN:
949 		return put_user((int) sfp->keep_orphan, ip);
950 	case SG_NEXT_CMD_LEN:
951 		result = get_user(val, ip);
952 		if (result)
953 			return result;
954 		sfp->next_cmd_len = (val > 0) ? val : 0;
955 		return 0;
956 	case SG_GET_VERSION_NUM:
957 		return put_user(sg_version_num, ip);
958 	case SG_GET_ACCESS_COUNT:
959 		/* faked - we don't have a real access count anymore */
960 		val = (sdp->device ? 1 : 0);
961 		return put_user(val, ip);
962 	case SG_GET_REQUEST_TABLE:
963 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
964 			return -EFAULT;
965 		else {
966 			sg_req_info_t *rinfo;
967 			unsigned int ms;
968 
969 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
970 								GFP_KERNEL);
971 			if (!rinfo)
972 				return -ENOMEM;
973 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
974 			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
975 			     ++val, srp = srp ? srp->nextrp : srp) {
976 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
977 				if (srp) {
978 					rinfo[val].req_state = srp->done + 1;
979 					rinfo[val].problem =
980 					    srp->header.masked_status &
981 					    srp->header.host_status &
982 					    srp->header.driver_status;
983 					if (srp->done)
984 						rinfo[val].duration =
985 							srp->header.duration;
986 					else {
987 						ms = jiffies_to_msecs(jiffies);
988 						rinfo[val].duration =
989 						    (ms > srp->header.duration) ?
990 						    (ms - srp->header.duration) : 0;
991 					}
992 					rinfo[val].orphan = srp->orphan;
993 					rinfo[val].sg_io_owned =
994 							srp->sg_io_owned;
995 					rinfo[val].pack_id =
996 							srp->header.pack_id;
997 					rinfo[val].usr_ptr =
998 							srp->header.usr_ptr;
999 				}
1000 			}
1001 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1002 			result = __copy_to_user(p, rinfo,
1003 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1004 			result = result ? -EFAULT : 0;
1005 			kfree(rinfo);
1006 			return result;
1007 		}
1008 	case SG_EMULATED_HOST:
1009 		if (sdp->detached)
1010 			return -ENODEV;
1011 		return put_user(sdp->device->host->hostt->emulated, ip);
1012 	case SG_SCSI_RESET:
1013 		if (sdp->detached)
1014 			return -ENODEV;
1015 		if (filp->f_flags & O_NONBLOCK) {
1016 			if (scsi_host_in_recovery(sdp->device->host))
1017 				return -EBUSY;
1018 		} else if (!scsi_block_when_processing_errors(sdp->device))
1019 			return -EBUSY;
1020 		result = get_user(val, ip);
1021 		if (result)
1022 			return result;
1023 		if (SG_SCSI_RESET_NOTHING == val)
1024 			return 0;
1025 		switch (val) {
1026 		case SG_SCSI_RESET_DEVICE:
1027 			val = SCSI_TRY_RESET_DEVICE;
1028 			break;
1029 		case SG_SCSI_RESET_BUS:
1030 			val = SCSI_TRY_RESET_BUS;
1031 			break;
1032 		case SG_SCSI_RESET_HOST:
1033 			val = SCSI_TRY_RESET_HOST;
1034 			break;
1035 		default:
1036 			return -EINVAL;
1037 		}
1038 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1039 			return -EACCES;
1040 		return (scsi_reset_provider(sdp->device, val) ==
1041 			SUCCESS) ? 0 : -EIO;
1042 	case SCSI_IOCTL_SEND_COMMAND:
1043 		if (sdp->detached)
1044 			return -ENODEV;
1045 		if (read_only) {
1046 			unsigned char opcode = WRITE_6;
1047 			Scsi_Ioctl_Command __user *siocp = p;
1048 
1049 			if (copy_from_user(&opcode, siocp->data, 1))
1050 				return -EFAULT;
1051 			if (!sg_allow_access(opcode, sdp->device->type))
1052 				return -EPERM;
1053 		}
1054 		return sg_scsi_ioctl(filp, sdp->device->request_queue, NULL, p);
1055 	case SG_SET_DEBUG:
1056 		result = get_user(val, ip);
1057 		if (result)
1058 			return result;
1059 		sdp->sgdebug = (char) val;
1060 		return 0;
1061 	case SCSI_IOCTL_GET_IDLUN:
1062 	case SCSI_IOCTL_GET_BUS_NUMBER:
1063 	case SCSI_IOCTL_PROBE_HOST:
1064 	case SG_GET_TRANSFORM:
1065 		if (sdp->detached)
1066 			return -ENODEV;
1067 		return scsi_ioctl(sdp->device, cmd_in, p);
1068 	case BLKSECTGET:
1069 		return put_user(sdp->device->request_queue->max_sectors * 512,
1070 				ip);
1071 	case BLKTRACESETUP:
1072 		return blk_trace_setup(sdp->device->request_queue,
1073 				       sdp->disk->disk_name,
1074 				       sdp->device->sdev_gendev.devt,
1075 				       (char *)arg);
1076 	case BLKTRACESTART:
1077 		return blk_trace_startstop(sdp->device->request_queue, 1);
1078 	case BLKTRACESTOP:
1079 		return blk_trace_startstop(sdp->device->request_queue, 0);
1080 	case BLKTRACETEARDOWN:
1081 		return blk_trace_remove(sdp->device->request_queue);
1082 	default:
1083 		if (read_only)
1084 			return -EPERM;	/* don't know so take safe approach */
1085 		return scsi_ioctl(sdp->device, cmd_in, p);
1086 	}
1087 }
1088 
1089 #ifdef CONFIG_COMPAT
1090 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1091 {
1092 	Sg_device *sdp;
1093 	Sg_fd *sfp;
1094 	struct scsi_device *sdev;
1095 
1096 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1097 		return -ENXIO;
1098 
1099 	sdev = sdp->device;
1100 	if (sdev->host->hostt->compat_ioctl) {
1101 		int ret;
1102 
1103 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1104 
1105 		return ret;
1106 	}
1107 
1108 	return -ENOIOCTLCMD;
1109 }
1110 #endif
1111 
1112 static unsigned int
1113 sg_poll(struct file *filp, poll_table * wait)
1114 {
1115 	unsigned int res = 0;
1116 	Sg_device *sdp;
1117 	Sg_fd *sfp;
1118 	Sg_request *srp;
1119 	int count = 0;
1120 	unsigned long iflags;
1121 
1122 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))
1123 	    || sfp->closed)
1124 		return POLLERR;
1125 	poll_wait(filp, &sfp->read_wait, wait);
1126 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1127 	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1128 		/* if any read waiting, flag it */
1129 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1130 			res = POLLIN | POLLRDNORM;
1131 		++count;
1132 	}
1133 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1134 
1135 	if (sdp->detached)
1136 		res |= POLLHUP;
1137 	else if (!sfp->cmd_q) {
1138 		if (0 == count)
1139 			res |= POLLOUT | POLLWRNORM;
1140 	} else if (count < SG_MAX_QUEUE)
1141 		res |= POLLOUT | POLLWRNORM;
1142 	SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
1143 				   sdp->disk->disk_name, (int) res));
1144 	return res;
1145 }
1146 
1147 static int
1148 sg_fasync(int fd, struct file *filp, int mode)
1149 {
1150 	int retval;
1151 	Sg_device *sdp;
1152 	Sg_fd *sfp;
1153 
1154 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1155 		return -ENXIO;
1156 	SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
1157 				   sdp->disk->disk_name, mode));
1158 
1159 	retval = fasync_helper(fd, filp, mode, &sfp->async_qp);
1160 	return (retval < 0) ? retval : 0;
1161 }
1162 
1163 static struct page *
1164 sg_vma_nopage(struct vm_area_struct *vma, unsigned long addr, int *type)
1165 {
1166 	Sg_fd *sfp;
1167 	struct page *page = NOPAGE_SIGBUS;
1168 	unsigned long offset, len, sa;
1169 	Sg_scatter_hold *rsv_schp;
1170 	struct scatterlist *sg;
1171 	int k;
1172 
1173 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1174 		return page;
1175 	rsv_schp = &sfp->reserve;
1176 	offset = addr - vma->vm_start;
1177 	if (offset >= rsv_schp->bufflen)
1178 		return page;
1179 	SCSI_LOG_TIMEOUT(3, printk("sg_vma_nopage: offset=%lu, scatg=%d\n",
1180 				   offset, rsv_schp->k_use_sg));
1181 	sg = rsv_schp->buffer;
1182 	sa = vma->vm_start;
1183 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
1184 	     ++k, sg = sg_next(sg)) {
1185 		len = vma->vm_end - sa;
1186 		len = (len < sg->length) ? len : sg->length;
1187 		if (offset < len) {
1188 			page = virt_to_page(page_address(sg_page(sg)) + offset);
1189 			get_page(page);	/* increment page count */
1190 			break;
1191 		}
1192 		sa += len;
1193 		offset -= len;
1194 	}
1195 
1196 	if (type)
1197 		*type = VM_FAULT_MINOR;
1198 	return page;
1199 }
1200 
1201 static struct vm_operations_struct sg_mmap_vm_ops = {
1202 	.nopage = sg_vma_nopage,
1203 };
1204 
1205 static int
1206 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1207 {
1208 	Sg_fd *sfp;
1209 	unsigned long req_sz, len, sa;
1210 	Sg_scatter_hold *rsv_schp;
1211 	int k;
1212 	struct scatterlist *sg;
1213 
1214 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1215 		return -ENXIO;
1216 	req_sz = vma->vm_end - vma->vm_start;
1217 	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
1218 				   (void *) vma->vm_start, (int) req_sz));
1219 	if (vma->vm_pgoff)
1220 		return -EINVAL;	/* want no offset */
1221 	rsv_schp = &sfp->reserve;
1222 	if (req_sz > rsv_schp->bufflen)
1223 		return -ENOMEM;	/* cannot map more than reserved buffer */
1224 
1225 	sa = vma->vm_start;
1226 	sg = rsv_schp->buffer;
1227 	for (k = 0; (k < rsv_schp->k_use_sg) && (sa < vma->vm_end);
1228 	     ++k, sg = sg_next(sg)) {
1229 		len = vma->vm_end - sa;
1230 		len = (len < sg->length) ? len : sg->length;
1231 		sa += len;
1232 	}
1233 
1234 	sfp->mmap_called = 1;
1235 	vma->vm_flags |= VM_RESERVED;
1236 	vma->vm_private_data = sfp;
1237 	vma->vm_ops = &sg_mmap_vm_ops;
1238 	return 0;
1239 }
1240 
1241 /* This function is a "bottom half" handler that is called by the
1242  * mid level when a command is completed (or has failed). */
1243 static void
1244 sg_cmd_done(void *data, char *sense, int result, int resid)
1245 {
1246 	Sg_request *srp = data;
1247 	Sg_device *sdp = NULL;
1248 	Sg_fd *sfp;
1249 	unsigned long iflags;
1250 	unsigned int ms;
1251 
1252 	if (NULL == srp) {
1253 		printk(KERN_ERR "sg_cmd_done: NULL request\n");
1254 		return;
1255 	}
1256 	sfp = srp->parentfp;
1257 	if (sfp)
1258 		sdp = sfp->parentdp;
1259 	if ((NULL == sdp) || sdp->detached) {
1260 		printk(KERN_INFO "sg_cmd_done: device detached\n");
1261 		return;
1262 	}
1263 
1264 
1265 	SCSI_LOG_TIMEOUT(4, printk("sg_cmd_done: %s, pack_id=%d, res=0x%x\n",
1266 		sdp->disk->disk_name, srp->header.pack_id, result));
1267 	srp->header.resid = resid;
1268 	ms = jiffies_to_msecs(jiffies);
1269 	srp->header.duration = (ms > srp->header.duration) ?
1270 				(ms - srp->header.duration) : 0;
1271 	if (0 != result) {
1272 		struct scsi_sense_hdr sshdr;
1273 
1274 		memcpy(srp->sense_b, sense, sizeof (srp->sense_b));
1275 		srp->header.status = 0xff & result;
1276 		srp->header.masked_status = status_byte(result);
1277 		srp->header.msg_status = msg_byte(result);
1278 		srp->header.host_status = host_byte(result);
1279 		srp->header.driver_status = driver_byte(result);
1280 		if ((sdp->sgdebug > 0) &&
1281 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1282 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1283 			__scsi_print_sense("sg_cmd_done", sense,
1284 					   SCSI_SENSE_BUFFERSIZE);
1285 
1286 		/* Following if statement is a patch supplied by Eric Youngdale */
1287 		if (driver_byte(result) != 0
1288 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1289 		    && !scsi_sense_is_deferred(&sshdr)
1290 		    && sshdr.sense_key == UNIT_ATTENTION
1291 		    && sdp->device->removable) {
1292 			/* Detected possible disc change. Set the bit - this */
1293 			/* may be used if there are filesystems using this device */
1294 			sdp->device->changed = 1;
1295 		}
1296 	}
1297 	/* Rely on write phase to clean out srp status values, so no "else" */
1298 
1299 	if (sfp->closed) {	/* whoops this fd already released, cleanup */
1300 		SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, freeing ...\n"));
1301 		sg_finish_rem_req(srp);
1302 		srp = NULL;
1303 		if (NULL == sfp->headrp) {
1304 			SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, final cleanup\n"));
1305 			if (0 == sg_remove_sfp(sdp, sfp)) {	/* device still present */
1306 				scsi_device_put(sdp->device);
1307 			}
1308 			sfp = NULL;
1309 		}
1310 	} else if (srp && srp->orphan) {
1311 		if (sfp->keep_orphan)
1312 			srp->sg_io_owned = 0;
1313 		else {
1314 			sg_finish_rem_req(srp);
1315 			srp = NULL;
1316 		}
1317 	}
1318 	if (sfp && srp) {
1319 		/* Now wake up any sg_read() that is waiting for this packet. */
1320 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1321 		write_lock_irqsave(&sfp->rq_list_lock, iflags);
1322 		srp->done = 1;
1323 		wake_up_interruptible(&sfp->read_wait);
1324 		write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1325 	}
1326 }
1327 
1328 static struct file_operations sg_fops = {
1329 	.owner = THIS_MODULE,
1330 	.read = sg_read,
1331 	.write = sg_write,
1332 	.poll = sg_poll,
1333 	.ioctl = sg_ioctl,
1334 #ifdef CONFIG_COMPAT
1335 	.compat_ioctl = sg_compat_ioctl,
1336 #endif
1337 	.open = sg_open,
1338 	.mmap = sg_mmap,
1339 	.release = sg_release,
1340 	.fasync = sg_fasync,
1341 };
1342 
1343 static struct class *sg_sysfs_class;
1344 
1345 static int sg_sysfs_valid = 0;
1346 
1347 static Sg_device *sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1348 {
1349 	struct request_queue *q = scsidp->request_queue;
1350 	Sg_device *sdp;
1351 	unsigned long iflags;
1352 	int error;
1353 	u32 k;
1354 
1355 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1356 	if (!sdp) {
1357 		printk(KERN_WARNING "kmalloc Sg_device failure\n");
1358 		return ERR_PTR(-ENOMEM);
1359 	}
1360 	error = -ENOMEM;
1361 	if (!idr_pre_get(&sg_index_idr, GFP_KERNEL)) {
1362 		printk(KERN_WARNING "idr expansion Sg_device failure\n");
1363 		goto out;
1364 	}
1365 
1366 	write_lock_irqsave(&sg_index_lock, iflags);
1367 	error = idr_get_new(&sg_index_idr, sdp, &k);
1368 	write_unlock_irqrestore(&sg_index_lock, iflags);
1369 
1370 	if (error) {
1371 		printk(KERN_WARNING "idr allocation Sg_device failure: %d\n",
1372 		       error);
1373 		goto out;
1374 	}
1375 
1376 	if (unlikely(k >= SG_MAX_DEVS))
1377 		goto overflow;
1378 
1379 	SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
1380 	sprintf(disk->disk_name, "sg%d", k);
1381 	disk->first_minor = k;
1382 	sdp->disk = disk;
1383 	sdp->device = scsidp;
1384 	init_waitqueue_head(&sdp->o_excl_wait);
1385 	sdp->sg_tablesize = min(q->max_hw_segments, q->max_phys_segments);
1386 	sdp->index = k;
1387 
1388 	error = 0;
1389  out:
1390 	if (error) {
1391 		kfree(sdp);
1392 		return ERR_PTR(error);
1393 	}
1394 	return sdp;
1395 
1396  overflow:
1397 	sdev_printk(KERN_WARNING, scsidp,
1398 		    "Unable to attach sg device type=%d, minor "
1399 		    "number exceeds %d\n", scsidp->type, SG_MAX_DEVS - 1);
1400 	error = -ENODEV;
1401 	goto out;
1402 }
1403 
1404 static int
1405 sg_add(struct class_device *cl_dev, struct class_interface *cl_intf)
1406 {
1407 	struct scsi_device *scsidp = to_scsi_device(cl_dev->dev);
1408 	struct gendisk *disk;
1409 	Sg_device *sdp = NULL;
1410 	struct cdev * cdev = NULL;
1411 	int error;
1412 	unsigned long iflags;
1413 
1414 	disk = alloc_disk(1);
1415 	if (!disk) {
1416 		printk(KERN_WARNING "alloc_disk failed\n");
1417 		return -ENOMEM;
1418 	}
1419 	disk->major = SCSI_GENERIC_MAJOR;
1420 
1421 	error = -ENOMEM;
1422 	cdev = cdev_alloc();
1423 	if (!cdev) {
1424 		printk(KERN_WARNING "cdev_alloc failed\n");
1425 		goto out;
1426 	}
1427 	cdev->owner = THIS_MODULE;
1428 	cdev->ops = &sg_fops;
1429 
1430 	sdp = sg_alloc(disk, scsidp);
1431 	if (IS_ERR(sdp)) {
1432 		printk(KERN_WARNING "sg_alloc failed\n");
1433 		error = PTR_ERR(sdp);
1434 		goto out;
1435 	}
1436 
1437 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1438 	if (error)
1439 		goto cdev_add_err;
1440 
1441 	sdp->cdev = cdev;
1442 	if (sg_sysfs_valid) {
1443 		struct class_device * sg_class_member;
1444 
1445 		sg_class_member = class_device_create(sg_sysfs_class, NULL,
1446 				MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1447 				cl_dev->dev, "%s",
1448 				disk->disk_name);
1449 		if (IS_ERR(sg_class_member)) {
1450 			printk(KERN_ERR "sg_add: "
1451 			       "class_device_create failed\n");
1452 			error = PTR_ERR(sg_class_member);
1453 			goto cdev_add_err;
1454 		}
1455 		class_set_devdata(sg_class_member, sdp);
1456 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1457 					  &sg_class_member->kobj, "generic");
1458 		if (error)
1459 			printk(KERN_ERR "sg_add: unable to make symlink "
1460 					"'generic' back to sg%d\n", sdp->index);
1461 	} else
1462 		printk(KERN_WARNING "sg_add: sg_sys Invalid\n");
1463 
1464 	sdev_printk(KERN_NOTICE, scsidp,
1465 		    "Attached scsi generic sg%d type %d\n", sdp->index,
1466 		    scsidp->type);
1467 
1468 	class_set_devdata(cl_dev, sdp);
1469 
1470 	return 0;
1471 
1472 cdev_add_err:
1473 	write_lock_irqsave(&sg_index_lock, iflags);
1474 	idr_remove(&sg_index_idr, sdp->index);
1475 	write_unlock_irqrestore(&sg_index_lock, iflags);
1476 	kfree(sdp);
1477 
1478 out:
1479 	put_disk(disk);
1480 	if (cdev)
1481 		cdev_del(cdev);
1482 	return error;
1483 }
1484 
1485 static void
1486 sg_remove(struct class_device *cl_dev, struct class_interface *cl_intf)
1487 {
1488 	struct scsi_device *scsidp = to_scsi_device(cl_dev->dev);
1489 	Sg_device *sdp = class_get_devdata(cl_dev);
1490 	unsigned long iflags;
1491 	Sg_fd *sfp;
1492 	Sg_fd *tsfp;
1493 	Sg_request *srp;
1494 	Sg_request *tsrp;
1495 	int delay;
1496 
1497 	if (!sdp)
1498 		return;
1499 
1500 	delay = 0;
1501 	write_lock_irqsave(&sg_index_lock, iflags);
1502 	if (sdp->headfp) {
1503 		sdp->detached = 1;
1504 		for (sfp = sdp->headfp; sfp; sfp = tsfp) {
1505 			tsfp = sfp->nextfp;
1506 			for (srp = sfp->headrp; srp; srp = tsrp) {
1507 				tsrp = srp->nextrp;
1508 				if (sfp->closed || (0 == sg_srp_done(srp, sfp)))
1509 					sg_finish_rem_req(srp);
1510 			}
1511 			if (sfp->closed) {
1512 				scsi_device_put(sdp->device);
1513 				__sg_remove_sfp(sdp, sfp);
1514 			} else {
1515 				delay = 1;
1516 				wake_up_interruptible(&sfp->read_wait);
1517 				kill_fasync(&sfp->async_qp, SIGPOLL,
1518 					    POLL_HUP);
1519 			}
1520 		}
1521 		SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d, dirty\n", sdp->index));
1522 		if (NULL == sdp->headfp) {
1523 			idr_remove(&sg_index_idr, sdp->index);
1524 		}
1525 	} else {	/* nothing active, simple case */
1526 		SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d\n", sdp->index));
1527 		idr_remove(&sg_index_idr, sdp->index);
1528 	}
1529 	write_unlock_irqrestore(&sg_index_lock, iflags);
1530 
1531 	sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1532 	class_device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1533 	cdev_del(sdp->cdev);
1534 	sdp->cdev = NULL;
1535 	put_disk(sdp->disk);
1536 	sdp->disk = NULL;
1537 	if (NULL == sdp->headfp)
1538 		kfree(sdp);
1539 
1540 	if (delay)
1541 		msleep(10);	/* dirty detach so delay device destruction */
1542 }
1543 
1544 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1545 module_param_named(def_reserved_size, def_reserved_size, int,
1546 		   S_IRUGO | S_IWUSR);
1547 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1548 
1549 MODULE_AUTHOR("Douglas Gilbert");
1550 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1551 MODULE_LICENSE("GPL");
1552 MODULE_VERSION(SG_VERSION_STR);
1553 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1554 
1555 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1556                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1557 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1558 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1559 
1560 static int __init
1561 init_sg(void)
1562 {
1563 	int rc;
1564 
1565 	if (scatter_elem_sz < PAGE_SIZE) {
1566 		scatter_elem_sz = PAGE_SIZE;
1567 		scatter_elem_sz_prev = scatter_elem_sz;
1568 	}
1569 	if (def_reserved_size >= 0)
1570 		sg_big_buff = def_reserved_size;
1571 	else
1572 		def_reserved_size = sg_big_buff;
1573 
1574 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1575 				    SG_MAX_DEVS, "sg");
1576 	if (rc)
1577 		return rc;
1578         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1579         if ( IS_ERR(sg_sysfs_class) ) {
1580 		rc = PTR_ERR(sg_sysfs_class);
1581 		goto err_out;
1582         }
1583 	sg_sysfs_valid = 1;
1584 	rc = scsi_register_interface(&sg_interface);
1585 	if (0 == rc) {
1586 #ifdef CONFIG_SCSI_PROC_FS
1587 		sg_proc_init();
1588 #endif				/* CONFIG_SCSI_PROC_FS */
1589 		return 0;
1590 	}
1591 	class_destroy(sg_sysfs_class);
1592 err_out:
1593 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1594 	return rc;
1595 }
1596 
1597 static void __exit
1598 exit_sg(void)
1599 {
1600 #ifdef CONFIG_SCSI_PROC_FS
1601 	sg_proc_cleanup();
1602 #endif				/* CONFIG_SCSI_PROC_FS */
1603 	scsi_unregister_interface(&sg_interface);
1604 	class_destroy(sg_sysfs_class);
1605 	sg_sysfs_valid = 0;
1606 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1607 				 SG_MAX_DEVS);
1608 	idr_destroy(&sg_index_idr);
1609 }
1610 
1611 static int
1612 sg_start_req(Sg_request * srp)
1613 {
1614 	int res;
1615 	Sg_fd *sfp = srp->parentfp;
1616 	sg_io_hdr_t *hp = &srp->header;
1617 	int dxfer_len = (int) hp->dxfer_len;
1618 	int dxfer_dir = hp->dxfer_direction;
1619 	Sg_scatter_hold *req_schp = &srp->data;
1620 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1621 
1622 	SCSI_LOG_TIMEOUT(4, printk("sg_start_req: dxfer_len=%d\n", dxfer_len));
1623 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1624 		return 0;
1625 	if (sg_allow_dio && (hp->flags & SG_FLAG_DIRECT_IO) &&
1626 	    (dxfer_dir != SG_DXFER_UNKNOWN) && (0 == hp->iovec_count) &&
1627 	    (!sfp->parentdp->device->host->unchecked_isa_dma)) {
1628 		res = sg_build_direct(srp, sfp, dxfer_len);
1629 		if (res <= 0)	/* -ve -> error, 0 -> done, 1 -> try indirect */
1630 			return res;
1631 	}
1632 	if ((!sg_res_in_use(sfp)) && (dxfer_len <= rsv_schp->bufflen))
1633 		sg_link_reserve(sfp, srp, dxfer_len);
1634 	else {
1635 		res = sg_build_indirect(req_schp, sfp, dxfer_len);
1636 		if (res) {
1637 			sg_remove_scat(req_schp);
1638 			return res;
1639 		}
1640 	}
1641 	return 0;
1642 }
1643 
1644 static void
1645 sg_finish_rem_req(Sg_request * srp)
1646 {
1647 	Sg_fd *sfp = srp->parentfp;
1648 	Sg_scatter_hold *req_schp = &srp->data;
1649 
1650 	SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
1651 	if (srp->res_used)
1652 		sg_unlink_reserve(sfp, srp);
1653 	else
1654 		sg_remove_scat(req_schp);
1655 	sg_remove_request(sfp, srp);
1656 }
1657 
1658 static int
1659 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1660 {
1661 	int sg_bufflen = tablesize * sizeof(struct scatterlist);
1662 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1663 
1664 	/*
1665 	 * TODO: test without low_dma, we should not need it since
1666 	 * the block layer will bounce the buffer for us
1667 	 *
1668 	 * XXX(hch): we shouldn't need GFP_DMA for the actual S/G list.
1669 	 */
1670 	if (sfp->low_dma)
1671 		 gfp_flags |= GFP_DMA;
1672 	schp->buffer = kzalloc(sg_bufflen, gfp_flags);
1673 	if (!schp->buffer)
1674 		return -ENOMEM;
1675 	sg_init_table(schp->buffer, tablesize);
1676 	schp->sglist_len = sg_bufflen;
1677 	return tablesize;	/* number of scat_gath elements allocated */
1678 }
1679 
1680 #ifdef SG_ALLOW_DIO_CODE
1681 /* vvvvvvvv  following code borrowed from st driver's direct IO vvvvvvvvv */
1682 	/* TODO: hopefully we can use the generic block layer code */
1683 
1684 /* Pin down user pages and put them into a scatter gather list. Returns <= 0 if
1685    - mapping of all pages not successful
1686    (i.e., either completely successful or fails)
1687 */
1688 static int
1689 st_map_user_pages(struct scatterlist *sgl, const unsigned int max_pages,
1690 	          unsigned long uaddr, size_t count, int rw)
1691 {
1692 	unsigned long end = (uaddr + count + PAGE_SIZE - 1) >> PAGE_SHIFT;
1693 	unsigned long start = uaddr >> PAGE_SHIFT;
1694 	const int nr_pages = end - start;
1695 	int res, i, j;
1696 	struct page **pages;
1697 
1698 	/* User attempted Overflow! */
1699 	if ((uaddr + count) < uaddr)
1700 		return -EINVAL;
1701 
1702 	/* Too big */
1703         if (nr_pages > max_pages)
1704 		return -ENOMEM;
1705 
1706 	/* Hmm? */
1707 	if (count == 0)
1708 		return 0;
1709 
1710 	if ((pages = kmalloc(max_pages * sizeof(*pages), GFP_ATOMIC)) == NULL)
1711 		return -ENOMEM;
1712 
1713         /* Try to fault in all of the necessary pages */
1714 	down_read(&current->mm->mmap_sem);
1715         /* rw==READ means read from drive, write into memory area */
1716 	res = get_user_pages(
1717 		current,
1718 		current->mm,
1719 		uaddr,
1720 		nr_pages,
1721 		rw == READ,
1722 		0, /* don't force */
1723 		pages,
1724 		NULL);
1725 	up_read(&current->mm->mmap_sem);
1726 
1727 	/* Errors and no page mapped should return here */
1728 	if (res < nr_pages)
1729 		goto out_unmap;
1730 
1731         for (i=0; i < nr_pages; i++) {
1732                 /* FIXME: flush superflous for rw==READ,
1733                  * probably wrong function for rw==WRITE
1734                  */
1735 		flush_dcache_page(pages[i]);
1736 		/* ?? Is locking needed? I don't think so */
1737 		/* if (TestSetPageLocked(pages[i]))
1738 		   goto out_unlock; */
1739         }
1740 
1741 	sg_set_page(sgl, pages[0], 0, uaddr & ~PAGE_MASK);
1742 	if (nr_pages > 1) {
1743 		sgl[0].length = PAGE_SIZE - sgl[0].offset;
1744 		count -= sgl[0].length;
1745 		for (i=1; i < nr_pages ; i++)
1746 			sg_set_page(&sgl[i], pages[i], count < PAGE_SIZE ? count : PAGE_SIZE, 0);
1747 	}
1748 	else {
1749 		sgl[0].length = count;
1750 	}
1751 
1752 	kfree(pages);
1753 	return nr_pages;
1754 
1755  out_unmap:
1756 	if (res > 0) {
1757 		for (j=0; j < res; j++)
1758 			page_cache_release(pages[j]);
1759 		res = 0;
1760 	}
1761 	kfree(pages);
1762 	return res;
1763 }
1764 
1765 
1766 /* And unmap them... */
1767 static int
1768 st_unmap_user_pages(struct scatterlist *sgl, const unsigned int nr_pages,
1769 		    int dirtied)
1770 {
1771 	int i;
1772 
1773 	for (i=0; i < nr_pages; i++) {
1774 		struct page *page = sg_page(&sgl[i]);
1775 
1776 		if (dirtied)
1777 			SetPageDirty(page);
1778 		/* unlock_page(page); */
1779 		/* FIXME: cache flush missing for rw==READ
1780 		 * FIXME: call the correct reference counting function
1781 		 */
1782 		page_cache_release(page);
1783 	}
1784 
1785 	return 0;
1786 }
1787 
1788 /* ^^^^^^^^  above code borrowed from st driver's direct IO ^^^^^^^^^ */
1789 #endif
1790 
1791 
1792 /* Returns: -ve -> error, 0 -> done, 1 -> try indirect */
1793 static int
1794 sg_build_direct(Sg_request * srp, Sg_fd * sfp, int dxfer_len)
1795 {
1796 #ifdef SG_ALLOW_DIO_CODE
1797 	sg_io_hdr_t *hp = &srp->header;
1798 	Sg_scatter_hold *schp = &srp->data;
1799 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1800 	int mx_sc_elems, res;
1801 	struct scsi_device *sdev = sfp->parentdp->device;
1802 
1803 	if (((unsigned long)hp->dxferp &
1804 			queue_dma_alignment(sdev->request_queue)) != 0)
1805 		return 1;
1806 
1807 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1808         if (mx_sc_elems <= 0) {
1809                 return 1;
1810         }
1811 	res = st_map_user_pages(schp->buffer, mx_sc_elems,
1812 				(unsigned long)hp->dxferp, dxfer_len,
1813 				(SG_DXFER_TO_DEV == hp->dxfer_direction) ? 1 : 0);
1814 	if (res <= 0) {
1815 		sg_remove_scat(schp);
1816 		return 1;
1817 	}
1818 	schp->k_use_sg = res;
1819 	schp->dio_in_use = 1;
1820 	hp->info |= SG_INFO_DIRECT_IO;
1821 	return 0;
1822 #else
1823 	return 1;
1824 #endif
1825 }
1826 
1827 static int
1828 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1829 {
1830 	struct scatterlist *sg;
1831 	int ret_sz = 0, k, rem_sz, num, mx_sc_elems;
1832 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1833 	int blk_size = buff_size;
1834 	struct page *p = NULL;
1835 
1836 	if (blk_size < 0)
1837 		return -EFAULT;
1838 	if (0 == blk_size)
1839 		++blk_size;	/* don't know why */
1840 /* round request up to next highest SG_SECTOR_SZ byte boundary */
1841 	blk_size = (blk_size + SG_SECTOR_MSK) & (~SG_SECTOR_MSK);
1842 	SCSI_LOG_TIMEOUT(4, printk("sg_build_indirect: buff_size=%d, blk_size=%d\n",
1843 				   buff_size, blk_size));
1844 
1845 	/* N.B. ret_sz carried into this block ... */
1846 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1847 	if (mx_sc_elems < 0)
1848 		return mx_sc_elems;	/* most likely -ENOMEM */
1849 
1850 	num = scatter_elem_sz;
1851 	if (unlikely(num != scatter_elem_sz_prev)) {
1852 		if (num < PAGE_SIZE) {
1853 			scatter_elem_sz = PAGE_SIZE;
1854 			scatter_elem_sz_prev = PAGE_SIZE;
1855 		} else
1856 			scatter_elem_sz_prev = num;
1857 	}
1858 	for (k = 0, sg = schp->buffer, rem_sz = blk_size;
1859 	     (rem_sz > 0) && (k < mx_sc_elems);
1860 	     ++k, rem_sz -= ret_sz, sg = sg_next(sg)) {
1861 
1862 		num = (rem_sz > scatter_elem_sz_prev) ?
1863 		      scatter_elem_sz_prev : rem_sz;
1864 		p = sg_page_malloc(num, sfp->low_dma, &ret_sz);
1865 		if (!p)
1866 			return -ENOMEM;
1867 
1868 		if (num == scatter_elem_sz_prev) {
1869 			if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1870 				scatter_elem_sz = ret_sz;
1871 				scatter_elem_sz_prev = ret_sz;
1872 			}
1873 		}
1874 		sg_set_page(sg, p, (ret_sz > num) ? num : ret_sz, 0);
1875 
1876 		SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k=%d, num=%d, "
1877 				 "ret_sz=%d\n", k, num, ret_sz));
1878 	}		/* end of for loop */
1879 
1880 	schp->k_use_sg = k;
1881 	SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, "
1882 			 "rem_sz=%d\n", k, rem_sz));
1883 
1884 	schp->bufflen = blk_size;
1885 	if (rem_sz > 0)	/* must have failed */
1886 		return -ENOMEM;
1887 
1888 	return 0;
1889 }
1890 
1891 static int
1892 sg_write_xfer(Sg_request * srp)
1893 {
1894 	sg_io_hdr_t *hp = &srp->header;
1895 	Sg_scatter_hold *schp = &srp->data;
1896 	struct scatterlist *sg = schp->buffer;
1897 	int num_xfer = 0;
1898 	int j, k, onum, usglen, ksglen, res;
1899 	int iovec_count = (int) hp->iovec_count;
1900 	int dxfer_dir = hp->dxfer_direction;
1901 	unsigned char *p;
1902 	unsigned char __user *up;
1903 	int new_interface = ('\0' == hp->interface_id) ? 0 : 1;
1904 
1905 	if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_TO_DEV == dxfer_dir) ||
1906 	    (SG_DXFER_TO_FROM_DEV == dxfer_dir)) {
1907 		num_xfer = (int) (new_interface ? hp->dxfer_len : hp->flags);
1908 		if (schp->bufflen < num_xfer)
1909 			num_xfer = schp->bufflen;
1910 	}
1911 	if ((num_xfer <= 0) || (schp->dio_in_use) ||
1912 	    (new_interface
1913 	     && ((SG_FLAG_NO_DXFER | SG_FLAG_MMAP_IO) & hp->flags)))
1914 		return 0;
1915 
1916 	SCSI_LOG_TIMEOUT(4, printk("sg_write_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n",
1917 			  num_xfer, iovec_count, schp->k_use_sg));
1918 	if (iovec_count) {
1919 		onum = iovec_count;
1920 		if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum))
1921 			return -EFAULT;
1922 	} else
1923 		onum = 1;
1924 
1925 	ksglen = sg->length;
1926 	p = page_address(sg_page(sg));
1927 	for (j = 0, k = 0; j < onum; ++j) {
1928 		res = sg_u_iovec(hp, iovec_count, j, 1, &usglen, &up);
1929 		if (res)
1930 			return res;
1931 
1932 		for (; p; sg = sg_next(sg), ksglen = sg->length,
1933 		     p = page_address(sg_page(sg))) {
1934 			if (usglen <= 0)
1935 				break;
1936 			if (ksglen > usglen) {
1937 				if (usglen >= num_xfer) {
1938 					if (__copy_from_user(p, up, num_xfer))
1939 						return -EFAULT;
1940 					return 0;
1941 				}
1942 				if (__copy_from_user(p, up, usglen))
1943 					return -EFAULT;
1944 				p += usglen;
1945 				ksglen -= usglen;
1946 				break;
1947 			} else {
1948 				if (ksglen >= num_xfer) {
1949 					if (__copy_from_user(p, up, num_xfer))
1950 						return -EFAULT;
1951 					return 0;
1952 				}
1953 				if (__copy_from_user(p, up, ksglen))
1954 					return -EFAULT;
1955 				up += ksglen;
1956 				usglen -= ksglen;
1957 			}
1958 			++k;
1959 			if (k >= schp->k_use_sg)
1960 				return 0;
1961 		}
1962 	}
1963 
1964 	return 0;
1965 }
1966 
1967 static int
1968 sg_u_iovec(sg_io_hdr_t * hp, int sg_num, int ind,
1969 	   int wr_xf, int *countp, unsigned char __user **up)
1970 {
1971 	int num_xfer = (int) hp->dxfer_len;
1972 	unsigned char __user *p = hp->dxferp;
1973 	int count;
1974 
1975 	if (0 == sg_num) {
1976 		if (wr_xf && ('\0' == hp->interface_id))
1977 			count = (int) hp->flags;	/* holds "old" input_size */
1978 		else
1979 			count = num_xfer;
1980 	} else {
1981 		sg_iovec_t iovec;
1982 		if (__copy_from_user(&iovec, p + ind*SZ_SG_IOVEC, SZ_SG_IOVEC))
1983 			return -EFAULT;
1984 		p = iovec.iov_base;
1985 		count = (int) iovec.iov_len;
1986 	}
1987 	if (!access_ok(wr_xf ? VERIFY_READ : VERIFY_WRITE, p, count))
1988 		return -EFAULT;
1989 	if (up)
1990 		*up = p;
1991 	if (countp)
1992 		*countp = count;
1993 	return 0;
1994 }
1995 
1996 static void
1997 sg_remove_scat(Sg_scatter_hold * schp)
1998 {
1999 	SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
2000 	if (schp->buffer && (schp->sglist_len > 0)) {
2001 		struct scatterlist *sg = schp->buffer;
2002 
2003 		if (schp->dio_in_use) {
2004 #ifdef SG_ALLOW_DIO_CODE
2005 			st_unmap_user_pages(sg, schp->k_use_sg, TRUE);
2006 #endif
2007 		} else {
2008 			int k;
2009 
2010 			for (k = 0; (k < schp->k_use_sg) && sg_page(sg);
2011 			     ++k, sg = sg_next(sg)) {
2012 				SCSI_LOG_TIMEOUT(5, printk(
2013 				    "sg_remove_scat: k=%d, pg=0x%p, len=%d\n",
2014 				    k, sg_page(sg), sg->length));
2015 				sg_page_free(sg_page(sg), sg->length);
2016 			}
2017 		}
2018 		kfree(schp->buffer);
2019 	}
2020 	memset(schp, 0, sizeof (*schp));
2021 }
2022 
2023 static int
2024 sg_read_xfer(Sg_request * srp)
2025 {
2026 	sg_io_hdr_t *hp = &srp->header;
2027 	Sg_scatter_hold *schp = &srp->data;
2028 	struct scatterlist *sg = schp->buffer;
2029 	int num_xfer = 0;
2030 	int j, k, onum, usglen, ksglen, res;
2031 	int iovec_count = (int) hp->iovec_count;
2032 	int dxfer_dir = hp->dxfer_direction;
2033 	unsigned char *p;
2034 	unsigned char __user *up;
2035 	int new_interface = ('\0' == hp->interface_id) ? 0 : 1;
2036 
2037 	if ((SG_DXFER_UNKNOWN == dxfer_dir) || (SG_DXFER_FROM_DEV == dxfer_dir)
2038 	    || (SG_DXFER_TO_FROM_DEV == dxfer_dir)) {
2039 		num_xfer = hp->dxfer_len;
2040 		if (schp->bufflen < num_xfer)
2041 			num_xfer = schp->bufflen;
2042 	}
2043 	if ((num_xfer <= 0) || (schp->dio_in_use) ||
2044 	    (new_interface
2045 	     && ((SG_FLAG_NO_DXFER | SG_FLAG_MMAP_IO) & hp->flags)))
2046 		return 0;
2047 
2048 	SCSI_LOG_TIMEOUT(4, printk("sg_read_xfer: num_xfer=%d, iovec_count=%d, k_use_sg=%d\n",
2049 			  num_xfer, iovec_count, schp->k_use_sg));
2050 	if (iovec_count) {
2051 		onum = iovec_count;
2052 		if (!access_ok(VERIFY_READ, hp->dxferp, SZ_SG_IOVEC * onum))
2053 			return -EFAULT;
2054 	} else
2055 		onum = 1;
2056 
2057 	p = page_address(sg_page(sg));
2058 	ksglen = sg->length;
2059 	for (j = 0, k = 0; j < onum; ++j) {
2060 		res = sg_u_iovec(hp, iovec_count, j, 0, &usglen, &up);
2061 		if (res)
2062 			return res;
2063 
2064 		for (; p; sg = sg_next(sg), ksglen = sg->length,
2065 		     p = page_address(sg_page(sg))) {
2066 			if (usglen <= 0)
2067 				break;
2068 			if (ksglen > usglen) {
2069 				if (usglen >= num_xfer) {
2070 					if (__copy_to_user(up, p, num_xfer))
2071 						return -EFAULT;
2072 					return 0;
2073 				}
2074 				if (__copy_to_user(up, p, usglen))
2075 					return -EFAULT;
2076 				p += usglen;
2077 				ksglen -= usglen;
2078 				break;
2079 			} else {
2080 				if (ksglen >= num_xfer) {
2081 					if (__copy_to_user(up, p, num_xfer))
2082 						return -EFAULT;
2083 					return 0;
2084 				}
2085 				if (__copy_to_user(up, p, ksglen))
2086 					return -EFAULT;
2087 				up += ksglen;
2088 				usglen -= ksglen;
2089 			}
2090 			++k;
2091 			if (k >= schp->k_use_sg)
2092 				return 0;
2093 		}
2094 	}
2095 
2096 	return 0;
2097 }
2098 
2099 static int
2100 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
2101 {
2102 	Sg_scatter_hold *schp = &srp->data;
2103 	struct scatterlist *sg = schp->buffer;
2104 	int k, num;
2105 
2106 	SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n",
2107 				   num_read_xfer));
2108 	if ((!outp) || (num_read_xfer <= 0))
2109 		return 0;
2110 
2111 	for (k = 0; (k < schp->k_use_sg) && sg_page(sg); ++k, sg = sg_next(sg)) {
2112 		num = sg->length;
2113 		if (num > num_read_xfer) {
2114 			if (__copy_to_user(outp, page_address(sg_page(sg)),
2115 					   num_read_xfer))
2116 				return -EFAULT;
2117 			break;
2118 		} else {
2119 			if (__copy_to_user(outp, page_address(sg_page(sg)),
2120 					   num))
2121 				return -EFAULT;
2122 			num_read_xfer -= num;
2123 			if (num_read_xfer <= 0)
2124 				break;
2125 			outp += num;
2126 		}
2127 	}
2128 
2129 	return 0;
2130 }
2131 
2132 static void
2133 sg_build_reserve(Sg_fd * sfp, int req_size)
2134 {
2135 	Sg_scatter_hold *schp = &sfp->reserve;
2136 
2137 	SCSI_LOG_TIMEOUT(4, printk("sg_build_reserve: req_size=%d\n", req_size));
2138 	do {
2139 		if (req_size < PAGE_SIZE)
2140 			req_size = PAGE_SIZE;
2141 		if (0 == sg_build_indirect(schp, sfp, req_size))
2142 			return;
2143 		else
2144 			sg_remove_scat(schp);
2145 		req_size >>= 1;	/* divide by 2 */
2146 	} while (req_size > (PAGE_SIZE / 2));
2147 }
2148 
2149 static void
2150 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
2151 {
2152 	Sg_scatter_hold *req_schp = &srp->data;
2153 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
2154 	struct scatterlist *sg = rsv_schp->buffer;
2155 	int k, num, rem;
2156 
2157 	srp->res_used = 1;
2158 	SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
2159 	rem = size;
2160 
2161 	for (k = 0; k < rsv_schp->k_use_sg; ++k, sg = sg_next(sg)) {
2162 		num = sg->length;
2163 		if (rem <= num) {
2164 			sfp->save_scat_len = num;
2165 			sg->length = rem;
2166 			req_schp->k_use_sg = k + 1;
2167 			req_schp->sglist_len = rsv_schp->sglist_len;
2168 			req_schp->buffer = rsv_schp->buffer;
2169 
2170 			req_schp->bufflen = size;
2171 			req_schp->b_malloc_len = rsv_schp->b_malloc_len;
2172 			break;
2173 		} else
2174 			rem -= num;
2175 	}
2176 
2177 	if (k >= rsv_schp->k_use_sg)
2178 		SCSI_LOG_TIMEOUT(1, printk("sg_link_reserve: BAD size\n"));
2179 }
2180 
2181 static void
2182 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2183 {
2184 	Sg_scatter_hold *req_schp = &srp->data;
2185 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
2186 
2187 	SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n",
2188 				   (int) req_schp->k_use_sg));
2189 	if ((rsv_schp->k_use_sg > 0) && (req_schp->k_use_sg > 0)) {
2190 		struct scatterlist *sg = rsv_schp->buffer;
2191 
2192 		if (sfp->save_scat_len > 0)
2193 			(sg + (req_schp->k_use_sg - 1))->length =
2194 			    (unsigned) sfp->save_scat_len;
2195 		else
2196 			SCSI_LOG_TIMEOUT(1, printk ("sg_unlink_reserve: BAD save_scat_len\n"));
2197 	}
2198 	req_schp->k_use_sg = 0;
2199 	req_schp->bufflen = 0;
2200 	req_schp->buffer = NULL;
2201 	req_schp->sglist_len = 0;
2202 	sfp->save_scat_len = 0;
2203 	srp->res_used = 0;
2204 }
2205 
2206 static Sg_request *
2207 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2208 {
2209 	Sg_request *resp;
2210 	unsigned long iflags;
2211 
2212 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2213 	for (resp = sfp->headrp; resp; resp = resp->nextrp) {
2214 		/* look for requests that are ready + not SG_IO owned */
2215 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
2216 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2217 			resp->done = 2;	/* guard against other readers */
2218 			break;
2219 		}
2220 	}
2221 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2222 	return resp;
2223 }
2224 
2225 #ifdef CONFIG_SCSI_PROC_FS
2226 static Sg_request *
2227 sg_get_nth_request(Sg_fd * sfp, int nth)
2228 {
2229 	Sg_request *resp;
2230 	unsigned long iflags;
2231 	int k;
2232 
2233 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2234 	for (k = 0, resp = sfp->headrp; resp && (k < nth);
2235 	     ++k, resp = resp->nextrp) ;
2236 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2237 	return resp;
2238 }
2239 #endif
2240 
2241 /* always adds to end of list */
2242 static Sg_request *
2243 sg_add_request(Sg_fd * sfp)
2244 {
2245 	int k;
2246 	unsigned long iflags;
2247 	Sg_request *resp;
2248 	Sg_request *rp = sfp->req_arr;
2249 
2250 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2251 	resp = sfp->headrp;
2252 	if (!resp) {
2253 		memset(rp, 0, sizeof (Sg_request));
2254 		rp->parentfp = sfp;
2255 		resp = rp;
2256 		sfp->headrp = resp;
2257 	} else {
2258 		if (0 == sfp->cmd_q)
2259 			resp = NULL;	/* command queuing disallowed */
2260 		else {
2261 			for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2262 				if (!rp->parentfp)
2263 					break;
2264 			}
2265 			if (k < SG_MAX_QUEUE) {
2266 				memset(rp, 0, sizeof (Sg_request));
2267 				rp->parentfp = sfp;
2268 				while (resp->nextrp)
2269 					resp = resp->nextrp;
2270 				resp->nextrp = rp;
2271 				resp = rp;
2272 			} else
2273 				resp = NULL;
2274 		}
2275 	}
2276 	if (resp) {
2277 		resp->nextrp = NULL;
2278 		resp->header.duration = jiffies_to_msecs(jiffies);
2279 	}
2280 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2281 	return resp;
2282 }
2283 
2284 /* Return of 1 for found; 0 for not found */
2285 static int
2286 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2287 {
2288 	Sg_request *prev_rp;
2289 	Sg_request *rp;
2290 	unsigned long iflags;
2291 	int res = 0;
2292 
2293 	if ((!sfp) || (!srp) || (!sfp->headrp))
2294 		return res;
2295 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2296 	prev_rp = sfp->headrp;
2297 	if (srp == prev_rp) {
2298 		sfp->headrp = prev_rp->nextrp;
2299 		prev_rp->parentfp = NULL;
2300 		res = 1;
2301 	} else {
2302 		while ((rp = prev_rp->nextrp)) {
2303 			if (srp == rp) {
2304 				prev_rp->nextrp = rp->nextrp;
2305 				rp->parentfp = NULL;
2306 				res = 1;
2307 				break;
2308 			}
2309 			prev_rp = rp;
2310 		}
2311 	}
2312 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2313 	return res;
2314 }
2315 
2316 #ifdef CONFIG_SCSI_PROC_FS
2317 static Sg_fd *
2318 sg_get_nth_sfp(Sg_device * sdp, int nth)
2319 {
2320 	Sg_fd *resp;
2321 	unsigned long iflags;
2322 	int k;
2323 
2324 	read_lock_irqsave(&sg_index_lock, iflags);
2325 	for (k = 0, resp = sdp->headfp; resp && (k < nth);
2326 	     ++k, resp = resp->nextfp) ;
2327 	read_unlock_irqrestore(&sg_index_lock, iflags);
2328 	return resp;
2329 }
2330 #endif
2331 
2332 static Sg_fd *
2333 sg_add_sfp(Sg_device * sdp, int dev)
2334 {
2335 	Sg_fd *sfp;
2336 	unsigned long iflags;
2337 	int bufflen;
2338 
2339 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2340 	if (!sfp)
2341 		return NULL;
2342 
2343 	init_waitqueue_head(&sfp->read_wait);
2344 	rwlock_init(&sfp->rq_list_lock);
2345 
2346 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2347 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2348 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2349 	sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2350 	    sdp->device->host->unchecked_isa_dma : 1;
2351 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2352 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2353 	sfp->parentdp = sdp;
2354 	write_lock_irqsave(&sg_index_lock, iflags);
2355 	if (!sdp->headfp)
2356 		sdp->headfp = sfp;
2357 	else {			/* add to tail of existing list */
2358 		Sg_fd *pfp = sdp->headfp;
2359 		while (pfp->nextfp)
2360 			pfp = pfp->nextfp;
2361 		pfp->nextfp = sfp;
2362 	}
2363 	write_unlock_irqrestore(&sg_index_lock, iflags);
2364 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
2365 	if (unlikely(sg_big_buff != def_reserved_size))
2366 		sg_big_buff = def_reserved_size;
2367 
2368 	bufflen = min_t(int, sg_big_buff,
2369 			sdp->device->request_queue->max_sectors * 512);
2370 	sg_build_reserve(sfp, bufflen);
2371 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp:   bufflen=%d, k_use_sg=%d\n",
2372 			   sfp->reserve.bufflen, sfp->reserve.k_use_sg));
2373 	return sfp;
2374 }
2375 
2376 static void
2377 __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2378 {
2379 	Sg_fd *fp;
2380 	Sg_fd *prev_fp;
2381 
2382 	prev_fp = sdp->headfp;
2383 	if (sfp == prev_fp)
2384 		sdp->headfp = prev_fp->nextfp;
2385 	else {
2386 		while ((fp = prev_fp->nextfp)) {
2387 			if (sfp == fp) {
2388 				prev_fp->nextfp = fp->nextfp;
2389 				break;
2390 			}
2391 			prev_fp = fp;
2392 		}
2393 	}
2394 	if (sfp->reserve.bufflen > 0) {
2395 		SCSI_LOG_TIMEOUT(6,
2396 			printk("__sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2397 			(int) sfp->reserve.bufflen, (int) sfp->reserve.k_use_sg));
2398 		sg_remove_scat(&sfp->reserve);
2399 	}
2400 	sfp->parentdp = NULL;
2401 	SCSI_LOG_TIMEOUT(6, printk("__sg_remove_sfp:    sfp=0x%p\n", sfp));
2402 	kfree(sfp);
2403 }
2404 
2405 /* Returns 0 in normal case, 1 when detached and sdp object removed */
2406 static int
2407 sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2408 {
2409 	Sg_request *srp;
2410 	Sg_request *tsrp;
2411 	int dirty = 0;
2412 	int res = 0;
2413 
2414 	for (srp = sfp->headrp; srp; srp = tsrp) {
2415 		tsrp = srp->nextrp;
2416 		if (sg_srp_done(srp, sfp))
2417 			sg_finish_rem_req(srp);
2418 		else
2419 			++dirty;
2420 	}
2421 	if (0 == dirty) {
2422 		unsigned long iflags;
2423 
2424 		write_lock_irqsave(&sg_index_lock, iflags);
2425 		__sg_remove_sfp(sdp, sfp);
2426 		if (sdp->detached && (NULL == sdp->headfp)) {
2427 			idr_remove(&sg_index_idr, sdp->index);
2428 			kfree(sdp);
2429 			res = 1;
2430 		}
2431 		write_unlock_irqrestore(&sg_index_lock, iflags);
2432 	} else {
2433 		/* MOD_INC's to inhibit unloading sg and associated adapter driver */
2434 		/* only bump the access_count if we actually succeeded in
2435 		 * throwing another counter on the host module */
2436 		scsi_device_get(sdp->device);	/* XXX: retval ignored? */
2437 		sfp->closed = 1;	/* flag dirty state on this fd */
2438 		SCSI_LOG_TIMEOUT(1, printk("sg_remove_sfp: worrisome, %d writes pending\n",
2439 				  dirty));
2440 	}
2441 	return res;
2442 }
2443 
2444 static int
2445 sg_res_in_use(Sg_fd * sfp)
2446 {
2447 	const Sg_request *srp;
2448 	unsigned long iflags;
2449 
2450 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2451 	for (srp = sfp->headrp; srp; srp = srp->nextrp)
2452 		if (srp->res_used)
2453 			break;
2454 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2455 	return srp ? 1 : 0;
2456 }
2457 
2458 /* The size fetched (value output via retSzp) set when non-NULL return */
2459 static struct page *
2460 sg_page_malloc(int rqSz, int lowDma, int *retSzp)
2461 {
2462 	struct page *resp = NULL;
2463 	gfp_t page_mask;
2464 	int order, a_size;
2465 	int resSz;
2466 
2467 	if ((rqSz <= 0) || (NULL == retSzp))
2468 		return resp;
2469 
2470 	if (lowDma)
2471 		page_mask = GFP_ATOMIC | GFP_DMA | __GFP_COMP | __GFP_NOWARN;
2472 	else
2473 		page_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
2474 
2475 	for (order = 0, a_size = PAGE_SIZE; a_size < rqSz;
2476 	     order++, a_size <<= 1) ;
2477 	resSz = a_size;		/* rounded up if necessary */
2478 	resp = alloc_pages(page_mask, order);
2479 	while ((!resp) && order) {
2480 		--order;
2481 		a_size >>= 1;	/* divide by 2, until PAGE_SIZE */
2482 		resp =  alloc_pages(page_mask, order);	/* try half */
2483 		resSz = a_size;
2484 	}
2485 	if (resp) {
2486 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2487 			memset(page_address(resp), 0, resSz);
2488 		*retSzp = resSz;
2489 	}
2490 	return resp;
2491 }
2492 
2493 static void
2494 sg_page_free(struct page *page, int size)
2495 {
2496 	int order, a_size;
2497 
2498 	if (!page)
2499 		return;
2500 	for (order = 0, a_size = PAGE_SIZE; a_size < size;
2501 	     order++, a_size <<= 1) ;
2502 	__free_pages(page, order);
2503 }
2504 
2505 #ifndef MAINTENANCE_IN_CMD
2506 #define MAINTENANCE_IN_CMD 0xa3
2507 #endif
2508 
2509 static unsigned char allow_ops[] = { TEST_UNIT_READY, REQUEST_SENSE,
2510 	INQUIRY, READ_CAPACITY, READ_BUFFER, READ_6, READ_10, READ_12,
2511 	READ_16, MODE_SENSE, MODE_SENSE_10, LOG_SENSE, REPORT_LUNS,
2512 	SERVICE_ACTION_IN, RECEIVE_DIAGNOSTIC, READ_LONG, MAINTENANCE_IN_CMD
2513 };
2514 
2515 static int
2516 sg_allow_access(unsigned char opcode, char dev_type)
2517 {
2518 	int k;
2519 
2520 	if (TYPE_SCANNER == dev_type)	/* TYPE_ROM maybe burner */
2521 		return 1;
2522 	for (k = 0; k < sizeof (allow_ops); ++k) {
2523 		if (opcode == allow_ops[k])
2524 			return 1;
2525 	}
2526 	return 0;
2527 }
2528 
2529 #ifdef CONFIG_SCSI_PROC_FS
2530 static int
2531 sg_idr_max_id(int id, void *p, void *data)
2532 {
2533 	int *k = data;
2534 
2535 	if (*k < id)
2536 		*k = id;
2537 
2538 	return 0;
2539 }
2540 
2541 static int
2542 sg_last_dev(void)
2543 {
2544 	int k = -1;
2545 	unsigned long iflags;
2546 
2547 	read_lock_irqsave(&sg_index_lock, iflags);
2548 	idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2549 	read_unlock_irqrestore(&sg_index_lock, iflags);
2550 	return k + 1;		/* origin 1 */
2551 }
2552 #endif
2553 
2554 static Sg_device *
2555 sg_get_dev(int dev)
2556 {
2557 	Sg_device *sdp;
2558 	unsigned long iflags;
2559 
2560 	read_lock_irqsave(&sg_index_lock, iflags);
2561 	sdp = idr_find(&sg_index_idr, dev);
2562 	read_unlock_irqrestore(&sg_index_lock, iflags);
2563 
2564 	return sdp;
2565 }
2566 
2567 #ifdef CONFIG_SCSI_PROC_FS
2568 
2569 static struct proc_dir_entry *sg_proc_sgp = NULL;
2570 
2571 static char sg_proc_sg_dirname[] = "scsi/sg";
2572 
2573 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2574 
2575 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2576 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2577 			          size_t count, loff_t *off);
2578 static struct file_operations adio_fops = {
2579 	/* .owner, .read and .llseek added in sg_proc_init() */
2580 	.open = sg_proc_single_open_adio,
2581 	.write = sg_proc_write_adio,
2582 	.release = single_release,
2583 };
2584 
2585 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2586 static ssize_t sg_proc_write_dressz(struct file *filp,
2587 		const char __user *buffer, size_t count, loff_t *off);
2588 static struct file_operations dressz_fops = {
2589 	.open = sg_proc_single_open_dressz,
2590 	.write = sg_proc_write_dressz,
2591 	.release = single_release,
2592 };
2593 
2594 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2595 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2596 static struct file_operations version_fops = {
2597 	.open = sg_proc_single_open_version,
2598 	.release = single_release,
2599 };
2600 
2601 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2602 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2603 static struct file_operations devhdr_fops = {
2604 	.open = sg_proc_single_open_devhdr,
2605 	.release = single_release,
2606 };
2607 
2608 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2609 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2610 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2611 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2612 static void dev_seq_stop(struct seq_file *s, void *v);
2613 static struct file_operations dev_fops = {
2614 	.open = sg_proc_open_dev,
2615 	.release = seq_release,
2616 };
2617 static struct seq_operations dev_seq_ops = {
2618 	.start = dev_seq_start,
2619 	.next  = dev_seq_next,
2620 	.stop  = dev_seq_stop,
2621 	.show  = sg_proc_seq_show_dev,
2622 };
2623 
2624 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2625 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2626 static struct file_operations devstrs_fops = {
2627 	.open = sg_proc_open_devstrs,
2628 	.release = seq_release,
2629 };
2630 static struct seq_operations devstrs_seq_ops = {
2631 	.start = dev_seq_start,
2632 	.next  = dev_seq_next,
2633 	.stop  = dev_seq_stop,
2634 	.show  = sg_proc_seq_show_devstrs,
2635 };
2636 
2637 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2638 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2639 static struct file_operations debug_fops = {
2640 	.open = sg_proc_open_debug,
2641 	.release = seq_release,
2642 };
2643 static struct seq_operations debug_seq_ops = {
2644 	.start = dev_seq_start,
2645 	.next  = dev_seq_next,
2646 	.stop  = dev_seq_stop,
2647 	.show  = sg_proc_seq_show_debug,
2648 };
2649 
2650 
2651 struct sg_proc_leaf {
2652 	const char * name;
2653 	struct file_operations * fops;
2654 };
2655 
2656 static struct sg_proc_leaf sg_proc_leaf_arr[] = {
2657 	{"allow_dio", &adio_fops},
2658 	{"debug", &debug_fops},
2659 	{"def_reserved_size", &dressz_fops},
2660 	{"device_hdr", &devhdr_fops},
2661 	{"devices", &dev_fops},
2662 	{"device_strs", &devstrs_fops},
2663 	{"version", &version_fops}
2664 };
2665 
2666 static int
2667 sg_proc_init(void)
2668 {
2669 	int k, mask;
2670 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2671 	struct proc_dir_entry *pdep;
2672 	struct sg_proc_leaf * leaf;
2673 
2674 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2675 	if (!sg_proc_sgp)
2676 		return 1;
2677 	for (k = 0; k < num_leaves; ++k) {
2678 		leaf = &sg_proc_leaf_arr[k];
2679 		mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2680 		pdep = create_proc_entry(leaf->name, mask, sg_proc_sgp);
2681 		if (pdep) {
2682 			leaf->fops->owner = THIS_MODULE,
2683 			leaf->fops->read = seq_read,
2684 			leaf->fops->llseek = seq_lseek,
2685 			pdep->proc_fops = leaf->fops;
2686 		}
2687 	}
2688 	return 0;
2689 }
2690 
2691 static void
2692 sg_proc_cleanup(void)
2693 {
2694 	int k;
2695 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2696 
2697 	if (!sg_proc_sgp)
2698 		return;
2699 	for (k = 0; k < num_leaves; ++k)
2700 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2701 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2702 }
2703 
2704 
2705 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2706 {
2707 	seq_printf(s, "%d\n", *((int *)s->private));
2708 	return 0;
2709 }
2710 
2711 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2712 {
2713 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2714 }
2715 
2716 static ssize_t
2717 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2718 		   size_t count, loff_t *off)
2719 {
2720 	int num;
2721 	char buff[11];
2722 
2723 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2724 		return -EACCES;
2725 	num = (count < 10) ? count : 10;
2726 	if (copy_from_user(buff, buffer, num))
2727 		return -EFAULT;
2728 	buff[num] = '\0';
2729 	sg_allow_dio = simple_strtoul(buff, NULL, 10) ? 1 : 0;
2730 	return count;
2731 }
2732 
2733 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2734 {
2735 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2736 }
2737 
2738 static ssize_t
2739 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2740 		     size_t count, loff_t *off)
2741 {
2742 	int num;
2743 	unsigned long k = ULONG_MAX;
2744 	char buff[11];
2745 
2746 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2747 		return -EACCES;
2748 	num = (count < 10) ? count : 10;
2749 	if (copy_from_user(buff, buffer, num))
2750 		return -EFAULT;
2751 	buff[num] = '\0';
2752 	k = simple_strtoul(buff, NULL, 10);
2753 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2754 		sg_big_buff = k;
2755 		return count;
2756 	}
2757 	return -ERANGE;
2758 }
2759 
2760 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2761 {
2762 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2763 		   sg_version_date);
2764 	return 0;
2765 }
2766 
2767 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2768 {
2769 	return single_open(file, sg_proc_seq_show_version, NULL);
2770 }
2771 
2772 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2773 {
2774 	seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
2775 		   "online\n");
2776 	return 0;
2777 }
2778 
2779 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2780 {
2781 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2782 }
2783 
2784 struct sg_proc_deviter {
2785 	loff_t	index;
2786 	size_t	max;
2787 };
2788 
2789 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2790 {
2791 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2792 
2793 	s->private = it;
2794 	if (! it)
2795 		return NULL;
2796 
2797 	it->index = *pos;
2798 	it->max = sg_last_dev();
2799 	if (it->index >= it->max)
2800 		return NULL;
2801 	return it;
2802 }
2803 
2804 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2805 {
2806 	struct sg_proc_deviter * it = s->private;
2807 
2808 	*pos = ++it->index;
2809 	return (it->index < it->max) ? it : NULL;
2810 }
2811 
2812 static void dev_seq_stop(struct seq_file *s, void *v)
2813 {
2814 	kfree(s->private);
2815 }
2816 
2817 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2818 {
2819         return seq_open(file, &dev_seq_ops);
2820 }
2821 
2822 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2823 {
2824 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2825 	Sg_device *sdp;
2826 	struct scsi_device *scsidp;
2827 
2828 	sdp = it ? sg_get_dev(it->index) : NULL;
2829 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2830 		seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
2831 			      scsidp->host->host_no, scsidp->channel,
2832 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2833 			      1,
2834 			      (int) scsidp->queue_depth,
2835 			      (int) scsidp->device_busy,
2836 			      (int) scsi_device_online(scsidp));
2837 	else
2838 		seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2839 	return 0;
2840 }
2841 
2842 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2843 {
2844         return seq_open(file, &devstrs_seq_ops);
2845 }
2846 
2847 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2848 {
2849 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2850 	Sg_device *sdp;
2851 	struct scsi_device *scsidp;
2852 
2853 	sdp = it ? sg_get_dev(it->index) : NULL;
2854 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2855 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2856 			   scsidp->vendor, scsidp->model, scsidp->rev);
2857 	else
2858 		seq_printf(s, "<no active device>\n");
2859 	return 0;
2860 }
2861 
2862 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2863 {
2864 	int k, m, new_interface, blen, usg;
2865 	Sg_request *srp;
2866 	Sg_fd *fp;
2867 	const sg_io_hdr_t *hp;
2868 	const char * cp;
2869 	unsigned int ms;
2870 
2871 	for (k = 0; (fp = sg_get_nth_sfp(sdp, k)); ++k) {
2872 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2873 			   "(res)sgat=%d low_dma=%d\n", k + 1,
2874 			   jiffies_to_msecs(fp->timeout),
2875 			   fp->reserve.bufflen,
2876 			   (int) fp->reserve.k_use_sg,
2877 			   (int) fp->low_dma);
2878 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=%d\n",
2879 			   (int) fp->cmd_q, (int) fp->force_packid,
2880 			   (int) fp->keep_orphan, (int) fp->closed);
2881 		for (m = 0; (srp = sg_get_nth_request(fp, m)); ++m) {
2882 			hp = &srp->header;
2883 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2884 			if (srp->res_used) {
2885 				if (new_interface &&
2886 				    (SG_FLAG_MMAP_IO & hp->flags))
2887 					cp = "     mmap>> ";
2888 				else
2889 					cp = "     rb>> ";
2890 			} else {
2891 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2892 					cp = "     dio>> ";
2893 				else
2894 					cp = "     ";
2895 			}
2896 			seq_printf(s, cp);
2897 			blen = srp->data.bufflen;
2898 			usg = srp->data.k_use_sg;
2899 			seq_printf(s, srp->done ?
2900 				   ((1 == srp->done) ?  "rcv:" : "fin:")
2901 				   : "act:");
2902 			seq_printf(s, " id=%d blen=%d",
2903 				   srp->header.pack_id, blen);
2904 			if (srp->done)
2905 				seq_printf(s, " dur=%d", hp->duration);
2906 			else {
2907 				ms = jiffies_to_msecs(jiffies);
2908 				seq_printf(s, " t_o/elap=%d/%d",
2909 					(new_interface ? hp->timeout :
2910 						  jiffies_to_msecs(fp->timeout)),
2911 					(ms > hp->duration ? ms - hp->duration : 0));
2912 			}
2913 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2914 				   (int) srp->data.cmd_opcode);
2915 		}
2916 		if (0 == m)
2917 			seq_printf(s, "     No requests active\n");
2918 	}
2919 }
2920 
2921 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2922 {
2923         return seq_open(file, &debug_seq_ops);
2924 }
2925 
2926 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2927 {
2928 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2929 	Sg_device *sdp;
2930 
2931 	if (it && (0 == it->index)) {
2932 		seq_printf(s, "max_active_device=%d(origin 1)\n",
2933 			   (int)it->max);
2934 		seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
2935 	}
2936 	sdp = it ? sg_get_dev(it->index) : NULL;
2937 	if (sdp) {
2938 		struct scsi_device *scsidp = sdp->device;
2939 
2940 		if (NULL == scsidp) {
2941 			seq_printf(s, "device %d detached ??\n",
2942 				   (int)it->index);
2943 			return 0;
2944 		}
2945 
2946 		if (sg_get_nth_sfp(sdp, 0)) {
2947 			seq_printf(s, " >>> device=%s ",
2948 				sdp->disk->disk_name);
2949 			if (sdp->detached)
2950 				seq_printf(s, "detached pending close ");
2951 			else
2952 				seq_printf
2953 				    (s, "scsi%d chan=%d id=%d lun=%d   em=%d",
2954 				     scsidp->host->host_no,
2955 				     scsidp->channel, scsidp->id,
2956 				     scsidp->lun,
2957 				     scsidp->host->hostt->emulated);
2958 			seq_printf(s, " sg_tablesize=%d excl=%d\n",
2959 				   sdp->sg_tablesize, sdp->exclude);
2960 		}
2961 		sg_proc_debug_helper(s, sdp);
2962 	}
2963 	return 0;
2964 }
2965 
2966 #endif				/* CONFIG_SCSI_PROC_FS */
2967 
2968 module_init(init_sg);
2969 module_exit(exit_sg);
2970