xref: /openbmc/linux/drivers/scsi/sg.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
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/blktrace_api.h>
51 #include <linux/smp_lock.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 
72 #define SG_MAX_DEVS 32768
73 
74 /*
75  * Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
76  * Then when using 32 bit integers x * m may overflow during the calculation.
77  * Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m
78  * calculates the same, but prevents the overflow when both m and d
79  * are "small" numbers (like HZ and USER_HZ).
80  * Of course an overflow is inavoidable if the result of muldiv doesn't fit
81  * in 32 bits.
82  */
83 #define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))
84 
85 #define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
86 
87 int sg_big_buff = SG_DEF_RESERVED_SIZE;
88 /* N.B. This variable is readable and writeable via
89    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
90    of this size (or less if there is not enough memory) will be reserved
91    for use by this file descriptor. [Deprecated usage: this variable is also
92    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
93    the kernel (i.e. it is not a module).] */
94 static int def_reserved_size = -1;	/* picks up init parameter */
95 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
96 
97 static int scatter_elem_sz = SG_SCATTER_SZ;
98 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
99 
100 #define SG_SECTOR_SZ 512
101 
102 static int sg_add(struct device *, struct class_interface *);
103 static void sg_remove(struct device *, struct class_interface *);
104 
105 static DEFINE_IDR(sg_index_idr);
106 static DEFINE_RWLOCK(sg_index_lock);	/* Also used to lock
107 							   file descriptor list for device */
108 
109 static struct class_interface sg_interface = {
110 	.add_dev	= sg_add,
111 	.remove_dev	= sg_remove,
112 };
113 
114 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
115 	unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
116 	unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
117 	unsigned bufflen;	/* Size of (aggregate) data buffer */
118 	struct page **pages;
119 	int page_order;
120 	char dio_in_use;	/* 0->indirect IO (or mmap), 1->dio */
121 	unsigned char cmd_opcode; /* first byte of command */
122 } Sg_scatter_hold;
123 
124 struct sg_device;		/* forward declarations */
125 struct sg_fd;
126 
127 typedef struct sg_request {	/* SG_MAX_QUEUE requests outstanding per file */
128 	struct sg_request *nextrp;	/* NULL -> tail request (slist) */
129 	struct sg_fd *parentfp;	/* NULL -> not in use */
130 	Sg_scatter_hold data;	/* hold buffer, perhaps scatter list */
131 	sg_io_hdr_t header;	/* scsi command+info, see <scsi/sg.h> */
132 	unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
133 	char res_used;		/* 1 -> using reserve buffer, 0 -> not ... */
134 	char orphan;		/* 1 -> drop on sight, 0 -> normal */
135 	char sg_io_owned;	/* 1 -> packet belongs to SG_IO */
136 	volatile char done;	/* 0->before bh, 1->before read, 2->read */
137 	struct request *rq;
138 	struct bio *bio;
139 	struct execute_work ew;
140 } Sg_request;
141 
142 typedef struct sg_fd {		/* holds the state of a file descriptor */
143 	struct list_head sfd_siblings;
144 	struct sg_device *parentdp;	/* owning device */
145 	wait_queue_head_t read_wait;	/* queue read until command done */
146 	rwlock_t rq_list_lock;	/* protect access to list in req_arr */
147 	int timeout;		/* defaults to SG_DEFAULT_TIMEOUT      */
148 	int timeout_user;	/* defaults to SG_DEFAULT_TIMEOUT_USER */
149 	Sg_scatter_hold reserve;	/* buffer held for this file descriptor */
150 	unsigned save_scat_len;	/* original length of trunc. scat. element */
151 	Sg_request *headrp;	/* head of request slist, NULL->empty */
152 	struct fasync_struct *async_qp;	/* used by asynchronous notification */
153 	Sg_request req_arr[SG_MAX_QUEUE];	/* used as singly-linked list */
154 	char low_dma;		/* as in parent but possibly overridden to 1 */
155 	char force_packid;	/* 1 -> pack_id input to read(), 0 -> ignored */
156 	volatile char closed;	/* 1 -> fd closed but request(s) outstanding */
157 	char cmd_q;		/* 1 -> allow command queuing, 0 -> don't */
158 	char next_cmd_len;	/* 0 -> automatic (def), >0 -> use on next write() */
159 	char keep_orphan;	/* 0 -> drop orphan (def), 1 -> keep for read() */
160 	char mmap_called;	/* 0 -> mmap() never called on this fd */
161 	struct kref f_ref;
162 	struct execute_work ew;
163 } Sg_fd;
164 
165 typedef struct sg_device { /* holds the state of each scsi generic device */
166 	struct scsi_device *device;
167 	wait_queue_head_t o_excl_wait;	/* queue open() when O_EXCL in use */
168 	int sg_tablesize;	/* adapter's max scatter-gather table size */
169 	u32 index;		/* device index number */
170 	struct list_head sfds;
171 	volatile char detached;	/* 0->attached, 1->detached pending removal */
172 	volatile char exclude;	/* opened for exclusive access */
173 	char sgdebug;		/* 0->off, 1->sense, 9->dump dev, 10-> all devs */
174 	struct gendisk *disk;
175 	struct cdev * cdev;	/* char_dev [sysfs: /sys/cdev/major/sg<n>] */
176 	struct kref d_ref;
177 } Sg_device;
178 
179 /* tasklet or soft irq callback */
180 static void sg_rq_end_io(struct request *rq, int uptodate);
181 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
182 static void sg_finish_rem_req(Sg_request * srp);
183 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
184 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
185 			   Sg_request * srp);
186 static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
187 			const char __user *buf, size_t count, int blocking,
188 			int read_only, int sg_io_owned, Sg_request **o_srp);
189 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
190 			   unsigned char *cmnd, int timeout, int blocking);
191 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
192 static void sg_remove_scat(Sg_scatter_hold * schp);
193 static void sg_build_reserve(Sg_fd * sfp, int req_size);
194 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
195 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
196 static Sg_fd *sg_add_sfp(Sg_device * sdp, int dev);
197 static void sg_remove_sfp(struct kref *);
198 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
199 static Sg_request *sg_add_request(Sg_fd * sfp);
200 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
201 static int sg_res_in_use(Sg_fd * sfp);
202 static Sg_device *sg_get_dev(int dev);
203 static void sg_put_dev(Sg_device *sdp);
204 
205 #define SZ_SG_HEADER sizeof(struct sg_header)
206 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
207 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
208 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
209 
210 static int sg_allow_access(struct file *filp, unsigned char *cmd)
211 {
212 	struct sg_fd *sfp = (struct sg_fd *)filp->private_data;
213 	struct request_queue *q = sfp->parentdp->device->request_queue;
214 
215 	if (sfp->parentdp->device->type == TYPE_SCANNER)
216 		return 0;
217 
218 	return blk_verify_command(&q->cmd_filter,
219 				  cmd, filp->f_mode & FMODE_WRITE);
220 }
221 
222 static int
223 sg_open(struct inode *inode, struct file *filp)
224 {
225 	int dev = iminor(inode);
226 	int flags = filp->f_flags;
227 	struct request_queue *q;
228 	Sg_device *sdp;
229 	Sg_fd *sfp;
230 	int res;
231 	int retval;
232 
233 	lock_kernel();
234 	nonseekable_open(inode, filp);
235 	SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
236 	sdp = sg_get_dev(dev);
237 	if (IS_ERR(sdp)) {
238 		retval = PTR_ERR(sdp);
239 		sdp = NULL;
240 		goto sg_put;
241 	}
242 
243 	/* This driver's module count bumped by fops_get in <linux/fs.h> */
244 	/* Prevent the device driver from vanishing while we sleep */
245 	retval = scsi_device_get(sdp->device);
246 	if (retval)
247 		goto sg_put;
248 
249 	if (!((flags & O_NONBLOCK) ||
250 	      scsi_block_when_processing_errors(sdp->device))) {
251 		retval = -ENXIO;
252 		/* we are in error recovery for this device */
253 		goto error_out;
254 	}
255 
256 	if (flags & O_EXCL) {
257 		if (O_RDONLY == (flags & O_ACCMODE)) {
258 			retval = -EPERM; /* Can't lock it with read only access */
259 			goto error_out;
260 		}
261 		if (!list_empty(&sdp->sfds) && (flags & O_NONBLOCK)) {
262 			retval = -EBUSY;
263 			goto error_out;
264 		}
265 		res = 0;
266 		__wait_event_interruptible(sdp->o_excl_wait,
267 					   ((!list_empty(&sdp->sfds) || sdp->exclude) ? 0 : (sdp->exclude = 1)), res);
268 		if (res) {
269 			retval = res;	/* -ERESTARTSYS because signal hit process */
270 			goto error_out;
271 		}
272 	} else if (sdp->exclude) {	/* some other fd has an exclusive lock on dev */
273 		if (flags & O_NONBLOCK) {
274 			retval = -EBUSY;
275 			goto error_out;
276 		}
277 		res = 0;
278 		__wait_event_interruptible(sdp->o_excl_wait, (!sdp->exclude),
279 					   res);
280 		if (res) {
281 			retval = res;	/* -ERESTARTSYS because signal hit process */
282 			goto error_out;
283 		}
284 	}
285 	if (sdp->detached) {
286 		retval = -ENODEV;
287 		goto error_out;
288 	}
289 	if (list_empty(&sdp->sfds)) {	/* no existing opens on this device */
290 		sdp->sgdebug = 0;
291 		q = sdp->device->request_queue;
292 		sdp->sg_tablesize = min(q->max_hw_segments,
293 					q->max_phys_segments);
294 	}
295 	if ((sfp = sg_add_sfp(sdp, dev)))
296 		filp->private_data = sfp;
297 	else {
298 		if (flags & O_EXCL) {
299 			sdp->exclude = 0;	/* undo if error */
300 			wake_up_interruptible(&sdp->o_excl_wait);
301 		}
302 		retval = -ENOMEM;
303 		goto error_out;
304 	}
305 	retval = 0;
306 error_out:
307 	if (retval)
308 		scsi_device_put(sdp->device);
309 sg_put:
310 	if (sdp)
311 		sg_put_dev(sdp);
312 	unlock_kernel();
313 	return retval;
314 }
315 
316 /* Following function was formerly called 'sg_close' */
317 static int
318 sg_release(struct inode *inode, struct file *filp)
319 {
320 	Sg_device *sdp;
321 	Sg_fd *sfp;
322 
323 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
324 		return -ENXIO;
325 	SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
326 
327 	sfp->closed = 1;
328 
329 	sdp->exclude = 0;
330 	wake_up_interruptible(&sdp->o_excl_wait);
331 
332 	kref_put(&sfp->f_ref, sg_remove_sfp);
333 	return 0;
334 }
335 
336 static ssize_t
337 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
338 {
339 	Sg_device *sdp;
340 	Sg_fd *sfp;
341 	Sg_request *srp;
342 	int req_pack_id = -1;
343 	sg_io_hdr_t *hp;
344 	struct sg_header *old_hdr = NULL;
345 	int retval = 0;
346 
347 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
348 		return -ENXIO;
349 	SCSI_LOG_TIMEOUT(3, printk("sg_read: %s, count=%d\n",
350 				   sdp->disk->disk_name, (int) count));
351 
352 	if (!access_ok(VERIFY_WRITE, buf, count))
353 		return -EFAULT;
354 	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
355 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
356 		if (!old_hdr)
357 			return -ENOMEM;
358 		if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
359 			retval = -EFAULT;
360 			goto free_old_hdr;
361 		}
362 		if (old_hdr->reply_len < 0) {
363 			if (count >= SZ_SG_IO_HDR) {
364 				sg_io_hdr_t *new_hdr;
365 				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
366 				if (!new_hdr) {
367 					retval = -ENOMEM;
368 					goto free_old_hdr;
369 				}
370 				retval =__copy_from_user
371 				    (new_hdr, buf, SZ_SG_IO_HDR);
372 				req_pack_id = new_hdr->pack_id;
373 				kfree(new_hdr);
374 				if (retval) {
375 					retval = -EFAULT;
376 					goto free_old_hdr;
377 				}
378 			}
379 		} else
380 			req_pack_id = old_hdr->pack_id;
381 	}
382 	srp = sg_get_rq_mark(sfp, req_pack_id);
383 	if (!srp) {		/* now wait on packet to arrive */
384 		if (sdp->detached) {
385 			retval = -ENODEV;
386 			goto free_old_hdr;
387 		}
388 		if (filp->f_flags & O_NONBLOCK) {
389 			retval = -EAGAIN;
390 			goto free_old_hdr;
391 		}
392 		while (1) {
393 			retval = 0; /* following macro beats race condition */
394 			__wait_event_interruptible(sfp->read_wait,
395 				(sdp->detached ||
396 				(srp = sg_get_rq_mark(sfp, req_pack_id))),
397 				retval);
398 			if (sdp->detached) {
399 				retval = -ENODEV;
400 				goto free_old_hdr;
401 			}
402 			if (0 == retval)
403 				break;
404 
405 			/* -ERESTARTSYS as signal hit process */
406 			goto free_old_hdr;
407 		}
408 	}
409 	if (srp->header.interface_id != '\0') {
410 		retval = sg_new_read(sfp, buf, count, srp);
411 		goto free_old_hdr;
412 	}
413 
414 	hp = &srp->header;
415 	if (old_hdr == NULL) {
416 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
417 		if (! old_hdr) {
418 			retval = -ENOMEM;
419 			goto free_old_hdr;
420 		}
421 	}
422 	memset(old_hdr, 0, SZ_SG_HEADER);
423 	old_hdr->reply_len = (int) hp->timeout;
424 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
425 	old_hdr->pack_id = hp->pack_id;
426 	old_hdr->twelve_byte =
427 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
428 	old_hdr->target_status = hp->masked_status;
429 	old_hdr->host_status = hp->host_status;
430 	old_hdr->driver_status = hp->driver_status;
431 	if ((CHECK_CONDITION & hp->masked_status) ||
432 	    (DRIVER_SENSE & hp->driver_status))
433 		memcpy(old_hdr->sense_buffer, srp->sense_b,
434 		       sizeof (old_hdr->sense_buffer));
435 	switch (hp->host_status) {
436 	/* This setup of 'result' is for backward compatibility and is best
437 	   ignored by the user who should use target, host + driver status */
438 	case DID_OK:
439 	case DID_PASSTHROUGH:
440 	case DID_SOFT_ERROR:
441 		old_hdr->result = 0;
442 		break;
443 	case DID_NO_CONNECT:
444 	case DID_BUS_BUSY:
445 	case DID_TIME_OUT:
446 		old_hdr->result = EBUSY;
447 		break;
448 	case DID_BAD_TARGET:
449 	case DID_ABORT:
450 	case DID_PARITY:
451 	case DID_RESET:
452 	case DID_BAD_INTR:
453 		old_hdr->result = EIO;
454 		break;
455 	case DID_ERROR:
456 		old_hdr->result = (srp->sense_b[0] == 0 &&
457 				  hp->masked_status == GOOD) ? 0 : EIO;
458 		break;
459 	default:
460 		old_hdr->result = EIO;
461 		break;
462 	}
463 
464 	/* Now copy the result back to the user buffer.  */
465 	if (count >= SZ_SG_HEADER) {
466 		if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
467 			retval = -EFAULT;
468 			goto free_old_hdr;
469 		}
470 		buf += SZ_SG_HEADER;
471 		if (count > old_hdr->reply_len)
472 			count = old_hdr->reply_len;
473 		if (count > SZ_SG_HEADER) {
474 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
475 				retval = -EFAULT;
476 				goto free_old_hdr;
477 			}
478 		}
479 	} else
480 		count = (old_hdr->result == 0) ? 0 : -EIO;
481 	sg_finish_rem_req(srp);
482 	retval = count;
483 free_old_hdr:
484 	kfree(old_hdr);
485 	return retval;
486 }
487 
488 static ssize_t
489 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
490 {
491 	sg_io_hdr_t *hp = &srp->header;
492 	int err = 0;
493 	int len;
494 
495 	if (count < SZ_SG_IO_HDR) {
496 		err = -EINVAL;
497 		goto err_out;
498 	}
499 	hp->sb_len_wr = 0;
500 	if ((hp->mx_sb_len > 0) && hp->sbp) {
501 		if ((CHECK_CONDITION & hp->masked_status) ||
502 		    (DRIVER_SENSE & hp->driver_status)) {
503 			int sb_len = SCSI_SENSE_BUFFERSIZE;
504 			sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
505 			len = 8 + (int) srp->sense_b[7];	/* Additional sense length field */
506 			len = (len > sb_len) ? sb_len : len;
507 			if (copy_to_user(hp->sbp, srp->sense_b, len)) {
508 				err = -EFAULT;
509 				goto err_out;
510 			}
511 			hp->sb_len_wr = len;
512 		}
513 	}
514 	if (hp->masked_status || hp->host_status || hp->driver_status)
515 		hp->info |= SG_INFO_CHECK;
516 	if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
517 		err = -EFAULT;
518 		goto err_out;
519 	}
520 err_out:
521 	sg_finish_rem_req(srp);
522 	return (0 == err) ? count : err;
523 }
524 
525 static ssize_t
526 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
527 {
528 	int mxsize, cmd_size, k;
529 	int input_size, blocking;
530 	unsigned char opcode;
531 	Sg_device *sdp;
532 	Sg_fd *sfp;
533 	Sg_request *srp;
534 	struct sg_header old_hdr;
535 	sg_io_hdr_t *hp;
536 	unsigned char cmnd[MAX_COMMAND_SIZE];
537 
538 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
539 		return -ENXIO;
540 	SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n",
541 				   sdp->disk->disk_name, (int) count));
542 	if (sdp->detached)
543 		return -ENODEV;
544 	if (!((filp->f_flags & O_NONBLOCK) ||
545 	      scsi_block_when_processing_errors(sdp->device)))
546 		return -ENXIO;
547 
548 	if (!access_ok(VERIFY_READ, buf, count))
549 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
550 	if (count < SZ_SG_HEADER)
551 		return -EIO;
552 	if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
553 		return -EFAULT;
554 	blocking = !(filp->f_flags & O_NONBLOCK);
555 	if (old_hdr.reply_len < 0)
556 		return sg_new_write(sfp, filp, buf, count,
557 				    blocking, 0, 0, NULL);
558 	if (count < (SZ_SG_HEADER + 6))
559 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
560 
561 	if (!(srp = sg_add_request(sfp))) {
562 		SCSI_LOG_TIMEOUT(1, printk("sg_write: queue full\n"));
563 		return -EDOM;
564 	}
565 	buf += SZ_SG_HEADER;
566 	__get_user(opcode, buf);
567 	if (sfp->next_cmd_len > 0) {
568 		if (sfp->next_cmd_len > MAX_COMMAND_SIZE) {
569 			SCSI_LOG_TIMEOUT(1, printk("sg_write: command length too long\n"));
570 			sfp->next_cmd_len = 0;
571 			sg_remove_request(sfp, srp);
572 			return -EIO;
573 		}
574 		cmd_size = sfp->next_cmd_len;
575 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
576 	} else {
577 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
578 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
579 			cmd_size = 12;
580 	}
581 	SCSI_LOG_TIMEOUT(4, printk(
582 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
583 /* Determine buffer size.  */
584 	input_size = count - cmd_size;
585 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
586 	mxsize -= SZ_SG_HEADER;
587 	input_size -= SZ_SG_HEADER;
588 	if (input_size < 0) {
589 		sg_remove_request(sfp, srp);
590 		return -EIO;	/* User did not pass enough bytes for this command. */
591 	}
592 	hp = &srp->header;
593 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
594 	hp->cmd_len = (unsigned char) cmd_size;
595 	hp->iovec_count = 0;
596 	hp->mx_sb_len = 0;
597 	if (input_size > 0)
598 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
599 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
600 	else
601 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
602 	hp->dxfer_len = mxsize;
603 	if (hp->dxfer_direction == SG_DXFER_TO_DEV)
604 		hp->dxferp = (char __user *)buf + cmd_size;
605 	else
606 		hp->dxferp = NULL;
607 	hp->sbp = NULL;
608 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
609 	hp->flags = input_size;	/* structure abuse ... */
610 	hp->pack_id = old_hdr.pack_id;
611 	hp->usr_ptr = NULL;
612 	if (__copy_from_user(cmnd, buf, cmd_size))
613 		return -EFAULT;
614 	/*
615 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
616 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
617 	 * is a non-zero input_size, so emit a warning.
618 	 */
619 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
620 		static char cmd[TASK_COMM_LEN];
621 		if (strcmp(current->comm, cmd) && printk_ratelimit()) {
622 			printk(KERN_WARNING
623 			       "sg_write: data in/out %d/%d bytes for SCSI command 0x%x--"
624 			       "guessing data in;\n" KERN_WARNING "   "
625 			       "program %s not setting count and/or reply_len properly\n",
626 			       old_hdr.reply_len - (int)SZ_SG_HEADER,
627 			       input_size, (unsigned int) cmnd[0],
628 			       current->comm);
629 			strcpy(cmd, current->comm);
630 		}
631 	}
632 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
633 	return (k < 0) ? k : count;
634 }
635 
636 static ssize_t
637 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
638 		 size_t count, int blocking, int read_only, int sg_io_owned,
639 		 Sg_request **o_srp)
640 {
641 	int k;
642 	Sg_request *srp;
643 	sg_io_hdr_t *hp;
644 	unsigned char cmnd[MAX_COMMAND_SIZE];
645 	int timeout;
646 	unsigned long ul_timeout;
647 
648 	if (count < SZ_SG_IO_HDR)
649 		return -EINVAL;
650 	if (!access_ok(VERIFY_READ, buf, count))
651 		return -EFAULT; /* protects following copy_from_user()s + get_user()s */
652 
653 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
654 	if (!(srp = sg_add_request(sfp))) {
655 		SCSI_LOG_TIMEOUT(1, printk("sg_new_write: queue full\n"));
656 		return -EDOM;
657 	}
658 	srp->sg_io_owned = sg_io_owned;
659 	hp = &srp->header;
660 	if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
661 		sg_remove_request(sfp, srp);
662 		return -EFAULT;
663 	}
664 	if (hp->interface_id != 'S') {
665 		sg_remove_request(sfp, srp);
666 		return -ENOSYS;
667 	}
668 	if (hp->flags & SG_FLAG_MMAP_IO) {
669 		if (hp->dxfer_len > sfp->reserve.bufflen) {
670 			sg_remove_request(sfp, srp);
671 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
672 		}
673 		if (hp->flags & SG_FLAG_DIRECT_IO) {
674 			sg_remove_request(sfp, srp);
675 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
676 		}
677 		if (sg_res_in_use(sfp)) {
678 			sg_remove_request(sfp, srp);
679 			return -EBUSY;	/* reserve buffer already being used */
680 		}
681 	}
682 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
683 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
684 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
685 		sg_remove_request(sfp, srp);
686 		return -EMSGSIZE;
687 	}
688 	if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
689 		sg_remove_request(sfp, srp);
690 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
691 	}
692 	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
693 		sg_remove_request(sfp, srp);
694 		return -EFAULT;
695 	}
696 	if (read_only && sg_allow_access(file, cmnd)) {
697 		sg_remove_request(sfp, srp);
698 		return -EPERM;
699 	}
700 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
701 	if (k < 0)
702 		return k;
703 	if (o_srp)
704 		*o_srp = srp;
705 	return count;
706 }
707 
708 static int
709 sg_common_write(Sg_fd * sfp, Sg_request * srp,
710 		unsigned char *cmnd, int timeout, int blocking)
711 {
712 	int k, data_dir;
713 	Sg_device *sdp = sfp->parentdp;
714 	sg_io_hdr_t *hp = &srp->header;
715 
716 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
717 	hp->status = 0;
718 	hp->masked_status = 0;
719 	hp->msg_status = 0;
720 	hp->info = 0;
721 	hp->host_status = 0;
722 	hp->driver_status = 0;
723 	hp->resid = 0;
724 	SCSI_LOG_TIMEOUT(4, printk("sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
725 			  (int) cmnd[0], (int) hp->cmd_len));
726 
727 	k = sg_start_req(srp, cmnd);
728 	if (k) {
729 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: start_req err=%d\n", k));
730 		sg_finish_rem_req(srp);
731 		return k;	/* probably out of space --> ENOMEM */
732 	}
733 	if (sdp->detached) {
734 		sg_finish_rem_req(srp);
735 		return -ENODEV;
736 	}
737 
738 	switch (hp->dxfer_direction) {
739 	case SG_DXFER_TO_FROM_DEV:
740 	case SG_DXFER_FROM_DEV:
741 		data_dir = DMA_FROM_DEVICE;
742 		break;
743 	case SG_DXFER_TO_DEV:
744 		data_dir = DMA_TO_DEVICE;
745 		break;
746 	case SG_DXFER_UNKNOWN:
747 		data_dir = DMA_BIDIRECTIONAL;
748 		break;
749 	default:
750 		data_dir = DMA_NONE;
751 		break;
752 	}
753 	hp->duration = jiffies_to_msecs(jiffies);
754 
755 	srp->rq->timeout = timeout;
756 	kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
757 	blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
758 			      srp->rq, 1, sg_rq_end_io);
759 	return 0;
760 }
761 
762 static int
763 sg_ioctl(struct inode *inode, struct file *filp,
764 	 unsigned int cmd_in, unsigned long arg)
765 {
766 	void __user *p = (void __user *)arg;
767 	int __user *ip = p;
768 	int result, val, read_only;
769 	Sg_device *sdp;
770 	Sg_fd *sfp;
771 	Sg_request *srp;
772 	unsigned long iflags;
773 
774 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
775 		return -ENXIO;
776 
777 	SCSI_LOG_TIMEOUT(3, printk("sg_ioctl: %s, cmd=0x%x\n",
778 				   sdp->disk->disk_name, (int) cmd_in));
779 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
780 
781 	switch (cmd_in) {
782 	case SG_IO:
783 		{
784 			int blocking = 1;	/* ignore O_NONBLOCK flag */
785 
786 			if (sdp->detached)
787 				return -ENODEV;
788 			if (!scsi_block_when_processing_errors(sdp->device))
789 				return -ENXIO;
790 			if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
791 				return -EFAULT;
792 			result =
793 			    sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
794 					 blocking, read_only, 1, &srp);
795 			if (result < 0)
796 				return result;
797 			while (1) {
798 				result = 0;	/* following macro to beat race condition */
799 				__wait_event_interruptible(sfp->read_wait,
800 					(srp->done || sdp->detached),
801 					result);
802 				if (sdp->detached)
803 					return -ENODEV;
804 				write_lock_irq(&sfp->rq_list_lock);
805 				if (srp->done) {
806 					srp->done = 2;
807 					write_unlock_irq(&sfp->rq_list_lock);
808 					break;
809 				}
810 				srp->orphan = 1;
811 				write_unlock_irq(&sfp->rq_list_lock);
812 				return result;	/* -ERESTARTSYS because signal hit process */
813 			}
814 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
815 			return (result < 0) ? result : 0;
816 		}
817 	case SG_SET_TIMEOUT:
818 		result = get_user(val, ip);
819 		if (result)
820 			return result;
821 		if (val < 0)
822 			return -EIO;
823 		if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
824 		    val = MULDIV (INT_MAX, USER_HZ, HZ);
825 		sfp->timeout_user = val;
826 		sfp->timeout = MULDIV (val, HZ, USER_HZ);
827 
828 		return 0;
829 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
830 				/* strange ..., for backward compatibility */
831 		return sfp->timeout_user;
832 	case SG_SET_FORCE_LOW_DMA:
833 		result = get_user(val, ip);
834 		if (result)
835 			return result;
836 		if (val) {
837 			sfp->low_dma = 1;
838 			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
839 				val = (int) sfp->reserve.bufflen;
840 				sg_remove_scat(&sfp->reserve);
841 				sg_build_reserve(sfp, val);
842 			}
843 		} else {
844 			if (sdp->detached)
845 				return -ENODEV;
846 			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
847 		}
848 		return 0;
849 	case SG_GET_LOW_DMA:
850 		return put_user((int) sfp->low_dma, ip);
851 	case SG_GET_SCSI_ID:
852 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
853 			return -EFAULT;
854 		else {
855 			sg_scsi_id_t __user *sg_idp = p;
856 
857 			if (sdp->detached)
858 				return -ENODEV;
859 			__put_user((int) sdp->device->host->host_no,
860 				   &sg_idp->host_no);
861 			__put_user((int) sdp->device->channel,
862 				   &sg_idp->channel);
863 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
864 			__put_user((int) sdp->device->lun, &sg_idp->lun);
865 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
866 			__put_user((short) sdp->device->host->cmd_per_lun,
867 				   &sg_idp->h_cmd_per_lun);
868 			__put_user((short) sdp->device->queue_depth,
869 				   &sg_idp->d_queue_depth);
870 			__put_user(0, &sg_idp->unused[0]);
871 			__put_user(0, &sg_idp->unused[1]);
872 			return 0;
873 		}
874 	case SG_SET_FORCE_PACK_ID:
875 		result = get_user(val, ip);
876 		if (result)
877 			return result;
878 		sfp->force_packid = val ? 1 : 0;
879 		return 0;
880 	case SG_GET_PACK_ID:
881 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
882 			return -EFAULT;
883 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
884 		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
885 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
886 				read_unlock_irqrestore(&sfp->rq_list_lock,
887 						       iflags);
888 				__put_user(srp->header.pack_id, ip);
889 				return 0;
890 			}
891 		}
892 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
893 		__put_user(-1, ip);
894 		return 0;
895 	case SG_GET_NUM_WAITING:
896 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
897 		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
898 			if ((1 == srp->done) && (!srp->sg_io_owned))
899 				++val;
900 		}
901 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
902 		return put_user(val, ip);
903 	case SG_GET_SG_TABLESIZE:
904 		return put_user(sdp->sg_tablesize, ip);
905 	case SG_SET_RESERVED_SIZE:
906 		result = get_user(val, ip);
907 		if (result)
908 			return result;
909                 if (val < 0)
910                         return -EINVAL;
911 		val = min_t(int, val,
912 				sdp->device->request_queue->max_sectors * 512);
913 		if (val != sfp->reserve.bufflen) {
914 			if (sg_res_in_use(sfp) || sfp->mmap_called)
915 				return -EBUSY;
916 			sg_remove_scat(&sfp->reserve);
917 			sg_build_reserve(sfp, val);
918 		}
919 		return 0;
920 	case SG_GET_RESERVED_SIZE:
921 		val = min_t(int, sfp->reserve.bufflen,
922 				sdp->device->request_queue->max_sectors * 512);
923 		return put_user(val, ip);
924 	case SG_SET_COMMAND_Q:
925 		result = get_user(val, ip);
926 		if (result)
927 			return result;
928 		sfp->cmd_q = val ? 1 : 0;
929 		return 0;
930 	case SG_GET_COMMAND_Q:
931 		return put_user((int) sfp->cmd_q, ip);
932 	case SG_SET_KEEP_ORPHAN:
933 		result = get_user(val, ip);
934 		if (result)
935 			return result;
936 		sfp->keep_orphan = val;
937 		return 0;
938 	case SG_GET_KEEP_ORPHAN:
939 		return put_user((int) sfp->keep_orphan, ip);
940 	case SG_NEXT_CMD_LEN:
941 		result = get_user(val, ip);
942 		if (result)
943 			return result;
944 		sfp->next_cmd_len = (val > 0) ? val : 0;
945 		return 0;
946 	case SG_GET_VERSION_NUM:
947 		return put_user(sg_version_num, ip);
948 	case SG_GET_ACCESS_COUNT:
949 		/* faked - we don't have a real access count anymore */
950 		val = (sdp->device ? 1 : 0);
951 		return put_user(val, ip);
952 	case SG_GET_REQUEST_TABLE:
953 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
954 			return -EFAULT;
955 		else {
956 			sg_req_info_t *rinfo;
957 			unsigned int ms;
958 
959 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
960 								GFP_KERNEL);
961 			if (!rinfo)
962 				return -ENOMEM;
963 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
964 			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
965 			     ++val, srp = srp ? srp->nextrp : srp) {
966 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
967 				if (srp) {
968 					rinfo[val].req_state = srp->done + 1;
969 					rinfo[val].problem =
970 					    srp->header.masked_status &
971 					    srp->header.host_status &
972 					    srp->header.driver_status;
973 					if (srp->done)
974 						rinfo[val].duration =
975 							srp->header.duration;
976 					else {
977 						ms = jiffies_to_msecs(jiffies);
978 						rinfo[val].duration =
979 						    (ms > srp->header.duration) ?
980 						    (ms - srp->header.duration) : 0;
981 					}
982 					rinfo[val].orphan = srp->orphan;
983 					rinfo[val].sg_io_owned =
984 							srp->sg_io_owned;
985 					rinfo[val].pack_id =
986 							srp->header.pack_id;
987 					rinfo[val].usr_ptr =
988 							srp->header.usr_ptr;
989 				}
990 			}
991 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
992 			result = __copy_to_user(p, rinfo,
993 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
994 			result = result ? -EFAULT : 0;
995 			kfree(rinfo);
996 			return result;
997 		}
998 	case SG_EMULATED_HOST:
999 		if (sdp->detached)
1000 			return -ENODEV;
1001 		return put_user(sdp->device->host->hostt->emulated, ip);
1002 	case SG_SCSI_RESET:
1003 		if (sdp->detached)
1004 			return -ENODEV;
1005 		if (filp->f_flags & O_NONBLOCK) {
1006 			if (scsi_host_in_recovery(sdp->device->host))
1007 				return -EBUSY;
1008 		} else if (!scsi_block_when_processing_errors(sdp->device))
1009 			return -EBUSY;
1010 		result = get_user(val, ip);
1011 		if (result)
1012 			return result;
1013 		if (SG_SCSI_RESET_NOTHING == val)
1014 			return 0;
1015 		switch (val) {
1016 		case SG_SCSI_RESET_DEVICE:
1017 			val = SCSI_TRY_RESET_DEVICE;
1018 			break;
1019 		case SG_SCSI_RESET_TARGET:
1020 			val = SCSI_TRY_RESET_TARGET;
1021 			break;
1022 		case SG_SCSI_RESET_BUS:
1023 			val = SCSI_TRY_RESET_BUS;
1024 			break;
1025 		case SG_SCSI_RESET_HOST:
1026 			val = SCSI_TRY_RESET_HOST;
1027 			break;
1028 		default:
1029 			return -EINVAL;
1030 		}
1031 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1032 			return -EACCES;
1033 		return (scsi_reset_provider(sdp->device, val) ==
1034 			SUCCESS) ? 0 : -EIO;
1035 	case SCSI_IOCTL_SEND_COMMAND:
1036 		if (sdp->detached)
1037 			return -ENODEV;
1038 		if (read_only) {
1039 			unsigned char opcode = WRITE_6;
1040 			Scsi_Ioctl_Command __user *siocp = p;
1041 
1042 			if (copy_from_user(&opcode, siocp->data, 1))
1043 				return -EFAULT;
1044 			if (sg_allow_access(filp, &opcode))
1045 				return -EPERM;
1046 		}
1047 		return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1048 	case SG_SET_DEBUG:
1049 		result = get_user(val, ip);
1050 		if (result)
1051 			return result;
1052 		sdp->sgdebug = (char) val;
1053 		return 0;
1054 	case SCSI_IOCTL_GET_IDLUN:
1055 	case SCSI_IOCTL_GET_BUS_NUMBER:
1056 	case SCSI_IOCTL_PROBE_HOST:
1057 	case SG_GET_TRANSFORM:
1058 		if (sdp->detached)
1059 			return -ENODEV;
1060 		return scsi_ioctl(sdp->device, cmd_in, p);
1061 	case BLKSECTGET:
1062 		return put_user(sdp->device->request_queue->max_sectors * 512,
1063 				ip);
1064 	case BLKTRACESETUP:
1065 		return blk_trace_setup(sdp->device->request_queue,
1066 				       sdp->disk->disk_name,
1067 				       MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1068 				       (char *)arg);
1069 	case BLKTRACESTART:
1070 		return blk_trace_startstop(sdp->device->request_queue, 1);
1071 	case BLKTRACESTOP:
1072 		return blk_trace_startstop(sdp->device->request_queue, 0);
1073 	case BLKTRACETEARDOWN:
1074 		return blk_trace_remove(sdp->device->request_queue);
1075 	default:
1076 		if (read_only)
1077 			return -EPERM;	/* don't know so take safe approach */
1078 		return scsi_ioctl(sdp->device, cmd_in, p);
1079 	}
1080 }
1081 
1082 #ifdef CONFIG_COMPAT
1083 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1084 {
1085 	Sg_device *sdp;
1086 	Sg_fd *sfp;
1087 	struct scsi_device *sdev;
1088 
1089 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1090 		return -ENXIO;
1091 
1092 	sdev = sdp->device;
1093 	if (sdev->host->hostt->compat_ioctl) {
1094 		int ret;
1095 
1096 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1097 
1098 		return ret;
1099 	}
1100 
1101 	return -ENOIOCTLCMD;
1102 }
1103 #endif
1104 
1105 static unsigned int
1106 sg_poll(struct file *filp, poll_table * wait)
1107 {
1108 	unsigned int res = 0;
1109 	Sg_device *sdp;
1110 	Sg_fd *sfp;
1111 	Sg_request *srp;
1112 	int count = 0;
1113 	unsigned long iflags;
1114 
1115 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))
1116 	    || sfp->closed)
1117 		return POLLERR;
1118 	poll_wait(filp, &sfp->read_wait, wait);
1119 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1120 	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1121 		/* if any read waiting, flag it */
1122 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1123 			res = POLLIN | POLLRDNORM;
1124 		++count;
1125 	}
1126 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1127 
1128 	if (sdp->detached)
1129 		res |= POLLHUP;
1130 	else if (!sfp->cmd_q) {
1131 		if (0 == count)
1132 			res |= POLLOUT | POLLWRNORM;
1133 	} else if (count < SG_MAX_QUEUE)
1134 		res |= POLLOUT | POLLWRNORM;
1135 	SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
1136 				   sdp->disk->disk_name, (int) res));
1137 	return res;
1138 }
1139 
1140 static int
1141 sg_fasync(int fd, struct file *filp, int mode)
1142 {
1143 	Sg_device *sdp;
1144 	Sg_fd *sfp;
1145 
1146 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1147 		return -ENXIO;
1148 	SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
1149 				   sdp->disk->disk_name, mode));
1150 
1151 	return fasync_helper(fd, filp, mode, &sfp->async_qp);
1152 }
1153 
1154 static int
1155 sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1156 {
1157 	Sg_fd *sfp;
1158 	unsigned long offset, len, sa;
1159 	Sg_scatter_hold *rsv_schp;
1160 	int k, length;
1161 
1162 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1163 		return VM_FAULT_SIGBUS;
1164 	rsv_schp = &sfp->reserve;
1165 	offset = vmf->pgoff << PAGE_SHIFT;
1166 	if (offset >= rsv_schp->bufflen)
1167 		return VM_FAULT_SIGBUS;
1168 	SCSI_LOG_TIMEOUT(3, printk("sg_vma_fault: offset=%lu, scatg=%d\n",
1169 				   offset, rsv_schp->k_use_sg));
1170 	sa = vma->vm_start;
1171 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1172 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1173 		len = vma->vm_end - sa;
1174 		len = (len < length) ? len : length;
1175 		if (offset < len) {
1176 			struct page *page = nth_page(rsv_schp->pages[k],
1177 						     offset >> PAGE_SHIFT);
1178 			get_page(page);	/* increment page count */
1179 			vmf->page = page;
1180 			return 0; /* success */
1181 		}
1182 		sa += len;
1183 		offset -= len;
1184 	}
1185 
1186 	return VM_FAULT_SIGBUS;
1187 }
1188 
1189 static struct vm_operations_struct sg_mmap_vm_ops = {
1190 	.fault = sg_vma_fault,
1191 };
1192 
1193 static int
1194 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1195 {
1196 	Sg_fd *sfp;
1197 	unsigned long req_sz, len, sa;
1198 	Sg_scatter_hold *rsv_schp;
1199 	int k, length;
1200 
1201 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1202 		return -ENXIO;
1203 	req_sz = vma->vm_end - vma->vm_start;
1204 	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
1205 				   (void *) vma->vm_start, (int) req_sz));
1206 	if (vma->vm_pgoff)
1207 		return -EINVAL;	/* want no offset */
1208 	rsv_schp = &sfp->reserve;
1209 	if (req_sz > rsv_schp->bufflen)
1210 		return -ENOMEM;	/* cannot map more than reserved buffer */
1211 
1212 	sa = vma->vm_start;
1213 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1214 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1215 		len = vma->vm_end - sa;
1216 		len = (len < length) ? len : length;
1217 		sa += len;
1218 	}
1219 
1220 	sfp->mmap_called = 1;
1221 	vma->vm_flags |= VM_RESERVED;
1222 	vma->vm_private_data = sfp;
1223 	vma->vm_ops = &sg_mmap_vm_ops;
1224 	return 0;
1225 }
1226 
1227 static void sg_rq_end_io_usercontext(struct work_struct *work)
1228 {
1229 	struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1230 	struct sg_fd *sfp = srp->parentfp;
1231 
1232 	sg_finish_rem_req(srp);
1233 	kref_put(&sfp->f_ref, sg_remove_sfp);
1234 }
1235 
1236 /*
1237  * This function is a "bottom half" handler that is called by the mid
1238  * level when a command is completed (or has failed).
1239  */
1240 static void sg_rq_end_io(struct request *rq, int uptodate)
1241 {
1242 	struct sg_request *srp = rq->end_io_data;
1243 	Sg_device *sdp;
1244 	Sg_fd *sfp;
1245 	unsigned long iflags;
1246 	unsigned int ms;
1247 	char *sense;
1248 	int result, resid, done = 1;
1249 
1250 	if (WARN_ON(srp->done != 0))
1251 		return;
1252 
1253 	sfp = srp->parentfp;
1254 	if (WARN_ON(sfp == NULL))
1255 		return;
1256 
1257 	sdp = sfp->parentdp;
1258 	if (unlikely(sdp->detached))
1259 		printk(KERN_INFO "sg_rq_end_io: device detached\n");
1260 
1261 	sense = rq->sense;
1262 	result = rq->errors;
1263 	resid = rq->data_len;
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 		srp->header.status = 0xff & result;
1275 		srp->header.masked_status = status_byte(result);
1276 		srp->header.msg_status = msg_byte(result);
1277 		srp->header.host_status = host_byte(result);
1278 		srp->header.driver_status = driver_byte(result);
1279 		if ((sdp->sgdebug > 0) &&
1280 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1281 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1282 			__scsi_print_sense("sg_cmd_done", sense,
1283 					   SCSI_SENSE_BUFFERSIZE);
1284 
1285 		/* Following if statement is a patch supplied by Eric Youngdale */
1286 		if (driver_byte(result) != 0
1287 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1288 		    && !scsi_sense_is_deferred(&sshdr)
1289 		    && sshdr.sense_key == UNIT_ATTENTION
1290 		    && sdp->device->removable) {
1291 			/* Detected possible disc change. Set the bit - this */
1292 			/* may be used if there are filesystems using this device */
1293 			sdp->device->changed = 1;
1294 		}
1295 	}
1296 	/* Rely on write phase to clean out srp status values, so no "else" */
1297 
1298 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1299 	if (unlikely(srp->orphan)) {
1300 		if (sfp->keep_orphan)
1301 			srp->sg_io_owned = 0;
1302 		else
1303 			done = 0;
1304 	}
1305 	srp->done = done;
1306 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1307 
1308 	if (likely(done)) {
1309 		/* Now wake up any sg_read() that is waiting for this
1310 		 * packet.
1311 		 */
1312 		wake_up_interruptible(&sfp->read_wait);
1313 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1314 		kref_put(&sfp->f_ref, sg_remove_sfp);
1315 	} else
1316 		execute_in_process_context(sg_rq_end_io_usercontext, &srp->ew);
1317 }
1318 
1319 static struct file_operations sg_fops = {
1320 	.owner = THIS_MODULE,
1321 	.read = sg_read,
1322 	.write = sg_write,
1323 	.poll = sg_poll,
1324 	.ioctl = sg_ioctl,
1325 #ifdef CONFIG_COMPAT
1326 	.compat_ioctl = sg_compat_ioctl,
1327 #endif
1328 	.open = sg_open,
1329 	.mmap = sg_mmap,
1330 	.release = sg_release,
1331 	.fasync = sg_fasync,
1332 };
1333 
1334 static struct class *sg_sysfs_class;
1335 
1336 static int sg_sysfs_valid = 0;
1337 
1338 static Sg_device *sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1339 {
1340 	struct request_queue *q = scsidp->request_queue;
1341 	Sg_device *sdp;
1342 	unsigned long iflags;
1343 	int error;
1344 	u32 k;
1345 
1346 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1347 	if (!sdp) {
1348 		printk(KERN_WARNING "kmalloc Sg_device failure\n");
1349 		return ERR_PTR(-ENOMEM);
1350 	}
1351 
1352 	if (!idr_pre_get(&sg_index_idr, GFP_KERNEL)) {
1353 		printk(KERN_WARNING "idr expansion Sg_device failure\n");
1354 		error = -ENOMEM;
1355 		goto out;
1356 	}
1357 
1358 	write_lock_irqsave(&sg_index_lock, iflags);
1359 
1360 	error = idr_get_new(&sg_index_idr, sdp, &k);
1361 	if (error) {
1362 		write_unlock_irqrestore(&sg_index_lock, iflags);
1363 		printk(KERN_WARNING "idr allocation Sg_device failure: %d\n",
1364 		       error);
1365 		goto out;
1366 	}
1367 
1368 	if (unlikely(k >= SG_MAX_DEVS))
1369 		goto overflow;
1370 
1371 	SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
1372 	sprintf(disk->disk_name, "sg%d", k);
1373 	disk->first_minor = k;
1374 	sdp->disk = disk;
1375 	sdp->device = scsidp;
1376 	INIT_LIST_HEAD(&sdp->sfds);
1377 	init_waitqueue_head(&sdp->o_excl_wait);
1378 	sdp->sg_tablesize = min(q->max_hw_segments, q->max_phys_segments);
1379 	sdp->index = k;
1380 	kref_init(&sdp->d_ref);
1381 
1382 	write_unlock_irqrestore(&sg_index_lock, iflags);
1383 
1384 	error = 0;
1385  out:
1386 	if (error) {
1387 		kfree(sdp);
1388 		return ERR_PTR(error);
1389 	}
1390 	return sdp;
1391 
1392  overflow:
1393 	idr_remove(&sg_index_idr, k);
1394 	write_unlock_irqrestore(&sg_index_lock, iflags);
1395 	sdev_printk(KERN_WARNING, scsidp,
1396 		    "Unable to attach sg device type=%d, minor "
1397 		    "number exceeds %d\n", scsidp->type, SG_MAX_DEVS - 1);
1398 	error = -ENODEV;
1399 	goto out;
1400 }
1401 
1402 static int
1403 sg_add(struct device *cl_dev, struct class_interface *cl_intf)
1404 {
1405 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1406 	struct gendisk *disk;
1407 	Sg_device *sdp = NULL;
1408 	struct cdev * cdev = NULL;
1409 	int error;
1410 	unsigned long iflags;
1411 
1412 	disk = alloc_disk(1);
1413 	if (!disk) {
1414 		printk(KERN_WARNING "alloc_disk failed\n");
1415 		return -ENOMEM;
1416 	}
1417 	disk->major = SCSI_GENERIC_MAJOR;
1418 
1419 	error = -ENOMEM;
1420 	cdev = cdev_alloc();
1421 	if (!cdev) {
1422 		printk(KERN_WARNING "cdev_alloc failed\n");
1423 		goto out;
1424 	}
1425 	cdev->owner = THIS_MODULE;
1426 	cdev->ops = &sg_fops;
1427 
1428 	sdp = sg_alloc(disk, scsidp);
1429 	if (IS_ERR(sdp)) {
1430 		printk(KERN_WARNING "sg_alloc failed\n");
1431 		error = PTR_ERR(sdp);
1432 		goto out;
1433 	}
1434 
1435 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1436 	if (error)
1437 		goto cdev_add_err;
1438 
1439 	sdp->cdev = cdev;
1440 	if (sg_sysfs_valid) {
1441 		struct device *sg_class_member;
1442 
1443 		sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1444 						MKDEV(SCSI_GENERIC_MAJOR,
1445 						      sdp->index),
1446 						sdp, "%s", disk->disk_name);
1447 		if (IS_ERR(sg_class_member)) {
1448 			printk(KERN_ERR "sg_add: "
1449 			       "device_create failed\n");
1450 			error = PTR_ERR(sg_class_member);
1451 			goto cdev_add_err;
1452 		}
1453 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1454 					  &sg_class_member->kobj, "generic");
1455 		if (error)
1456 			printk(KERN_ERR "sg_add: unable to make symlink "
1457 					"'generic' back to sg%d\n", sdp->index);
1458 	} else
1459 		printk(KERN_WARNING "sg_add: sg_sys Invalid\n");
1460 
1461 	sdev_printk(KERN_NOTICE, scsidp,
1462 		    "Attached scsi generic sg%d type %d\n", sdp->index,
1463 		    scsidp->type);
1464 
1465 	dev_set_drvdata(cl_dev, sdp);
1466 
1467 	return 0;
1468 
1469 cdev_add_err:
1470 	write_lock_irqsave(&sg_index_lock, iflags);
1471 	idr_remove(&sg_index_idr, sdp->index);
1472 	write_unlock_irqrestore(&sg_index_lock, iflags);
1473 	kfree(sdp);
1474 
1475 out:
1476 	put_disk(disk);
1477 	if (cdev)
1478 		cdev_del(cdev);
1479 	return error;
1480 }
1481 
1482 static void sg_device_destroy(struct kref *kref)
1483 {
1484 	struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1485 	unsigned long flags;
1486 
1487 	/* CAUTION!  Note that the device can still be found via idr_find()
1488 	 * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1489 	 * any other cleanup.
1490 	 */
1491 
1492 	write_lock_irqsave(&sg_index_lock, flags);
1493 	idr_remove(&sg_index_idr, sdp->index);
1494 	write_unlock_irqrestore(&sg_index_lock, flags);
1495 
1496 	SCSI_LOG_TIMEOUT(3,
1497 		printk("sg_device_destroy: %s\n",
1498 			sdp->disk->disk_name));
1499 
1500 	put_disk(sdp->disk);
1501 	kfree(sdp);
1502 }
1503 
1504 static void sg_remove(struct device *cl_dev, struct class_interface *cl_intf)
1505 {
1506 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1507 	Sg_device *sdp = dev_get_drvdata(cl_dev);
1508 	unsigned long iflags;
1509 	Sg_fd *sfp;
1510 
1511 	if (!sdp || sdp->detached)
1512 		return;
1513 
1514 	SCSI_LOG_TIMEOUT(3, printk("sg_remove: %s\n", sdp->disk->disk_name));
1515 
1516 	/* Need a write lock to set sdp->detached. */
1517 	write_lock_irqsave(&sg_index_lock, iflags);
1518 	sdp->detached = 1;
1519 	list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1520 		wake_up_interruptible(&sfp->read_wait);
1521 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1522 	}
1523 	write_unlock_irqrestore(&sg_index_lock, iflags);
1524 
1525 	sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1526 	device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1527 	cdev_del(sdp->cdev);
1528 	sdp->cdev = NULL;
1529 
1530 	sg_put_dev(sdp);
1531 }
1532 
1533 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1534 module_param_named(def_reserved_size, def_reserved_size, int,
1535 		   S_IRUGO | S_IWUSR);
1536 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1537 
1538 MODULE_AUTHOR("Douglas Gilbert");
1539 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1540 MODULE_LICENSE("GPL");
1541 MODULE_VERSION(SG_VERSION_STR);
1542 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1543 
1544 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1545                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1546 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1547 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1548 
1549 static int __init
1550 init_sg(void)
1551 {
1552 	int rc;
1553 
1554 	if (scatter_elem_sz < PAGE_SIZE) {
1555 		scatter_elem_sz = PAGE_SIZE;
1556 		scatter_elem_sz_prev = scatter_elem_sz;
1557 	}
1558 	if (def_reserved_size >= 0)
1559 		sg_big_buff = def_reserved_size;
1560 	else
1561 		def_reserved_size = sg_big_buff;
1562 
1563 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1564 				    SG_MAX_DEVS, "sg");
1565 	if (rc)
1566 		return rc;
1567         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1568         if ( IS_ERR(sg_sysfs_class) ) {
1569 		rc = PTR_ERR(sg_sysfs_class);
1570 		goto err_out;
1571         }
1572 	sg_sysfs_valid = 1;
1573 	rc = scsi_register_interface(&sg_interface);
1574 	if (0 == rc) {
1575 #ifdef CONFIG_SCSI_PROC_FS
1576 		sg_proc_init();
1577 #endif				/* CONFIG_SCSI_PROC_FS */
1578 		return 0;
1579 	}
1580 	class_destroy(sg_sysfs_class);
1581 err_out:
1582 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1583 	return rc;
1584 }
1585 
1586 static void __exit
1587 exit_sg(void)
1588 {
1589 #ifdef CONFIG_SCSI_PROC_FS
1590 	sg_proc_cleanup();
1591 #endif				/* CONFIG_SCSI_PROC_FS */
1592 	scsi_unregister_interface(&sg_interface);
1593 	class_destroy(sg_sysfs_class);
1594 	sg_sysfs_valid = 0;
1595 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1596 				 SG_MAX_DEVS);
1597 	idr_destroy(&sg_index_idr);
1598 }
1599 
1600 static int sg_start_req(Sg_request *srp, unsigned char *cmd)
1601 {
1602 	int res;
1603 	struct request *rq;
1604 	Sg_fd *sfp = srp->parentfp;
1605 	sg_io_hdr_t *hp = &srp->header;
1606 	int dxfer_len = (int) hp->dxfer_len;
1607 	int dxfer_dir = hp->dxfer_direction;
1608 	unsigned int iov_count = hp->iovec_count;
1609 	Sg_scatter_hold *req_schp = &srp->data;
1610 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1611 	struct request_queue *q = sfp->parentdp->device->request_queue;
1612 	struct rq_map_data *md, map_data;
1613 	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1614 
1615 	SCSI_LOG_TIMEOUT(4, printk(KERN_INFO "sg_start_req: dxfer_len=%d\n",
1616 				   dxfer_len));
1617 
1618 	rq = blk_get_request(q, rw, GFP_ATOMIC);
1619 	if (!rq)
1620 		return -ENOMEM;
1621 
1622 	memcpy(rq->cmd, cmd, hp->cmd_len);
1623 
1624 	rq->cmd_len = hp->cmd_len;
1625 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
1626 
1627 	srp->rq = rq;
1628 	rq->end_io_data = srp;
1629 	rq->sense = srp->sense_b;
1630 	rq->retries = SG_DEFAULT_RETRIES;
1631 
1632 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1633 		return 0;
1634 
1635 	if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1636 	    dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1637 	    !sfp->parentdp->device->host->unchecked_isa_dma &&
1638 	    blk_rq_aligned(q, hp->dxferp, dxfer_len))
1639 		md = NULL;
1640 	else
1641 		md = &map_data;
1642 
1643 	if (md) {
1644 		if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
1645 			sg_link_reserve(sfp, srp, dxfer_len);
1646 		else {
1647 			res = sg_build_indirect(req_schp, sfp, dxfer_len);
1648 			if (res)
1649 				return res;
1650 		}
1651 
1652 		md->pages = req_schp->pages;
1653 		md->page_order = req_schp->page_order;
1654 		md->nr_entries = req_schp->k_use_sg;
1655 		md->offset = 0;
1656 		md->null_mapped = hp->dxferp ? 0 : 1;
1657 	}
1658 
1659 	if (iov_count)
1660 		res = blk_rq_map_user_iov(q, rq, md, hp->dxferp, iov_count,
1661 					  hp->dxfer_len, GFP_ATOMIC);
1662 	else
1663 		res = blk_rq_map_user(q, rq, md, hp->dxferp,
1664 				      hp->dxfer_len, GFP_ATOMIC);
1665 
1666 	if (!res) {
1667 		srp->bio = rq->bio;
1668 
1669 		if (!md) {
1670 			req_schp->dio_in_use = 1;
1671 			hp->info |= SG_INFO_DIRECT_IO;
1672 		}
1673 	}
1674 	return res;
1675 }
1676 
1677 static void
1678 sg_finish_rem_req(Sg_request * srp)
1679 {
1680 	Sg_fd *sfp = srp->parentfp;
1681 	Sg_scatter_hold *req_schp = &srp->data;
1682 
1683 	SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
1684 	if (srp->res_used)
1685 		sg_unlink_reserve(sfp, srp);
1686 	else
1687 		sg_remove_scat(req_schp);
1688 
1689 	if (srp->rq) {
1690 		if (srp->bio)
1691 			blk_rq_unmap_user(srp->bio);
1692 
1693 		blk_put_request(srp->rq);
1694 	}
1695 
1696 	sg_remove_request(sfp, srp);
1697 }
1698 
1699 static int
1700 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1701 {
1702 	int sg_bufflen = tablesize * sizeof(struct page *);
1703 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1704 
1705 	schp->pages = kzalloc(sg_bufflen, gfp_flags);
1706 	if (!schp->pages)
1707 		return -ENOMEM;
1708 	schp->sglist_len = sg_bufflen;
1709 	return tablesize;	/* number of scat_gath elements allocated */
1710 }
1711 
1712 static int
1713 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1714 {
1715 	int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1716 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1717 	int blk_size = buff_size, order;
1718 	gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
1719 
1720 	if (blk_size < 0)
1721 		return -EFAULT;
1722 	if (0 == blk_size)
1723 		++blk_size;	/* don't know why */
1724 	/* round request up to next highest SG_SECTOR_SZ byte boundary */
1725 	blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1726 	SCSI_LOG_TIMEOUT(4, printk("sg_build_indirect: buff_size=%d, blk_size=%d\n",
1727 				   buff_size, blk_size));
1728 
1729 	/* N.B. ret_sz carried into this block ... */
1730 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1731 	if (mx_sc_elems < 0)
1732 		return mx_sc_elems;	/* most likely -ENOMEM */
1733 
1734 	num = scatter_elem_sz;
1735 	if (unlikely(num != scatter_elem_sz_prev)) {
1736 		if (num < PAGE_SIZE) {
1737 			scatter_elem_sz = PAGE_SIZE;
1738 			scatter_elem_sz_prev = PAGE_SIZE;
1739 		} else
1740 			scatter_elem_sz_prev = num;
1741 	}
1742 
1743 	if (sfp->low_dma)
1744 		gfp_mask |= GFP_DMA;
1745 
1746 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1747 		gfp_mask |= __GFP_ZERO;
1748 
1749 	order = get_order(num);
1750 retry:
1751 	ret_sz = 1 << (PAGE_SHIFT + order);
1752 
1753 	for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1754 	     k++, rem_sz -= ret_sz) {
1755 
1756 		num = (rem_sz > scatter_elem_sz_prev) ?
1757 			scatter_elem_sz_prev : rem_sz;
1758 
1759 		schp->pages[k] = alloc_pages(gfp_mask, order);
1760 		if (!schp->pages[k])
1761 			goto out;
1762 
1763 		if (num == scatter_elem_sz_prev) {
1764 			if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1765 				scatter_elem_sz = ret_sz;
1766 				scatter_elem_sz_prev = ret_sz;
1767 			}
1768 		}
1769 
1770 		SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k=%d, num=%d, "
1771 				 "ret_sz=%d\n", k, num, ret_sz));
1772 	}		/* end of for loop */
1773 
1774 	schp->page_order = order;
1775 	schp->k_use_sg = k;
1776 	SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, "
1777 			 "rem_sz=%d\n", k, rem_sz));
1778 
1779 	schp->bufflen = blk_size;
1780 	if (rem_sz > 0)	/* must have failed */
1781 		return -ENOMEM;
1782 	return 0;
1783 out:
1784 	for (i = 0; i < k; i++)
1785 		__free_pages(schp->pages[k], order);
1786 
1787 	if (--order >= 0)
1788 		goto retry;
1789 
1790 	return -ENOMEM;
1791 }
1792 
1793 static void
1794 sg_remove_scat(Sg_scatter_hold * schp)
1795 {
1796 	SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1797 	if (schp->pages && schp->sglist_len > 0) {
1798 		if (!schp->dio_in_use) {
1799 			int k;
1800 
1801 			for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1802 				SCSI_LOG_TIMEOUT(5, printk(
1803 				    "sg_remove_scat: k=%d, pg=0x%p\n",
1804 				    k, schp->pages[k]));
1805 				__free_pages(schp->pages[k], schp->page_order);
1806 			}
1807 
1808 			kfree(schp->pages);
1809 		}
1810 	}
1811 	memset(schp, 0, sizeof (*schp));
1812 }
1813 
1814 static int
1815 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1816 {
1817 	Sg_scatter_hold *schp = &srp->data;
1818 	int k, num;
1819 
1820 	SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n",
1821 				   num_read_xfer));
1822 	if ((!outp) || (num_read_xfer <= 0))
1823 		return 0;
1824 
1825 	num = 1 << (PAGE_SHIFT + schp->page_order);
1826 	for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1827 		if (num > num_read_xfer) {
1828 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1829 					   num_read_xfer))
1830 				return -EFAULT;
1831 			break;
1832 		} else {
1833 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1834 					   num))
1835 				return -EFAULT;
1836 			num_read_xfer -= num;
1837 			if (num_read_xfer <= 0)
1838 				break;
1839 			outp += num;
1840 		}
1841 	}
1842 
1843 	return 0;
1844 }
1845 
1846 static void
1847 sg_build_reserve(Sg_fd * sfp, int req_size)
1848 {
1849 	Sg_scatter_hold *schp = &sfp->reserve;
1850 
1851 	SCSI_LOG_TIMEOUT(4, printk("sg_build_reserve: req_size=%d\n", req_size));
1852 	do {
1853 		if (req_size < PAGE_SIZE)
1854 			req_size = PAGE_SIZE;
1855 		if (0 == sg_build_indirect(schp, sfp, req_size))
1856 			return;
1857 		else
1858 			sg_remove_scat(schp);
1859 		req_size >>= 1;	/* divide by 2 */
1860 	} while (req_size > (PAGE_SIZE / 2));
1861 }
1862 
1863 static void
1864 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
1865 {
1866 	Sg_scatter_hold *req_schp = &srp->data;
1867 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1868 	int k, num, rem;
1869 
1870 	srp->res_used = 1;
1871 	SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
1872 	rem = size;
1873 
1874 	num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1875 	for (k = 0; k < rsv_schp->k_use_sg; k++) {
1876 		if (rem <= num) {
1877 			req_schp->k_use_sg = k + 1;
1878 			req_schp->sglist_len = rsv_schp->sglist_len;
1879 			req_schp->pages = rsv_schp->pages;
1880 
1881 			req_schp->bufflen = size;
1882 			req_schp->page_order = rsv_schp->page_order;
1883 			break;
1884 		} else
1885 			rem -= num;
1886 	}
1887 
1888 	if (k >= rsv_schp->k_use_sg)
1889 		SCSI_LOG_TIMEOUT(1, printk("sg_link_reserve: BAD size\n"));
1890 }
1891 
1892 static void
1893 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
1894 {
1895 	Sg_scatter_hold *req_schp = &srp->data;
1896 
1897 	SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n",
1898 				   (int) req_schp->k_use_sg));
1899 	req_schp->k_use_sg = 0;
1900 	req_schp->bufflen = 0;
1901 	req_schp->pages = NULL;
1902 	req_schp->page_order = 0;
1903 	req_schp->sglist_len = 0;
1904 	sfp->save_scat_len = 0;
1905 	srp->res_used = 0;
1906 }
1907 
1908 static Sg_request *
1909 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
1910 {
1911 	Sg_request *resp;
1912 	unsigned long iflags;
1913 
1914 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1915 	for (resp = sfp->headrp; resp; resp = resp->nextrp) {
1916 		/* look for requests that are ready + not SG_IO owned */
1917 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
1918 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
1919 			resp->done = 2;	/* guard against other readers */
1920 			break;
1921 		}
1922 	}
1923 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1924 	return resp;
1925 }
1926 
1927 /* always adds to end of list */
1928 static Sg_request *
1929 sg_add_request(Sg_fd * sfp)
1930 {
1931 	int k;
1932 	unsigned long iflags;
1933 	Sg_request *resp;
1934 	Sg_request *rp = sfp->req_arr;
1935 
1936 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1937 	resp = sfp->headrp;
1938 	if (!resp) {
1939 		memset(rp, 0, sizeof (Sg_request));
1940 		rp->parentfp = sfp;
1941 		resp = rp;
1942 		sfp->headrp = resp;
1943 	} else {
1944 		if (0 == sfp->cmd_q)
1945 			resp = NULL;	/* command queuing disallowed */
1946 		else {
1947 			for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
1948 				if (!rp->parentfp)
1949 					break;
1950 			}
1951 			if (k < SG_MAX_QUEUE) {
1952 				memset(rp, 0, sizeof (Sg_request));
1953 				rp->parentfp = sfp;
1954 				while (resp->nextrp)
1955 					resp = resp->nextrp;
1956 				resp->nextrp = rp;
1957 				resp = rp;
1958 			} else
1959 				resp = NULL;
1960 		}
1961 	}
1962 	if (resp) {
1963 		resp->nextrp = NULL;
1964 		resp->header.duration = jiffies_to_msecs(jiffies);
1965 	}
1966 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1967 	return resp;
1968 }
1969 
1970 /* Return of 1 for found; 0 for not found */
1971 static int
1972 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
1973 {
1974 	Sg_request *prev_rp;
1975 	Sg_request *rp;
1976 	unsigned long iflags;
1977 	int res = 0;
1978 
1979 	if ((!sfp) || (!srp) || (!sfp->headrp))
1980 		return res;
1981 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1982 	prev_rp = sfp->headrp;
1983 	if (srp == prev_rp) {
1984 		sfp->headrp = prev_rp->nextrp;
1985 		prev_rp->parentfp = NULL;
1986 		res = 1;
1987 	} else {
1988 		while ((rp = prev_rp->nextrp)) {
1989 			if (srp == rp) {
1990 				prev_rp->nextrp = rp->nextrp;
1991 				rp->parentfp = NULL;
1992 				res = 1;
1993 				break;
1994 			}
1995 			prev_rp = rp;
1996 		}
1997 	}
1998 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1999 	return res;
2000 }
2001 
2002 static Sg_fd *
2003 sg_add_sfp(Sg_device * sdp, int dev)
2004 {
2005 	Sg_fd *sfp;
2006 	unsigned long iflags;
2007 	int bufflen;
2008 
2009 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2010 	if (!sfp)
2011 		return NULL;
2012 
2013 	init_waitqueue_head(&sfp->read_wait);
2014 	rwlock_init(&sfp->rq_list_lock);
2015 
2016 	kref_init(&sfp->f_ref);
2017 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2018 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2019 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2020 	sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2021 	    sdp->device->host->unchecked_isa_dma : 1;
2022 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2023 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2024 	sfp->parentdp = sdp;
2025 	write_lock_irqsave(&sg_index_lock, iflags);
2026 	list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2027 	write_unlock_irqrestore(&sg_index_lock, iflags);
2028 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
2029 	if (unlikely(sg_big_buff != def_reserved_size))
2030 		sg_big_buff = def_reserved_size;
2031 
2032 	bufflen = min_t(int, sg_big_buff,
2033 			sdp->device->request_queue->max_sectors * 512);
2034 	sg_build_reserve(sfp, bufflen);
2035 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp:   bufflen=%d, k_use_sg=%d\n",
2036 			   sfp->reserve.bufflen, sfp->reserve.k_use_sg));
2037 
2038 	kref_get(&sdp->d_ref);
2039 	__module_get(THIS_MODULE);
2040 	return sfp;
2041 }
2042 
2043 static void sg_remove_sfp_usercontext(struct work_struct *work)
2044 {
2045 	struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2046 	struct sg_device *sdp = sfp->parentdp;
2047 
2048 	/* Cleanup any responses which were never read(). */
2049 	while (sfp->headrp)
2050 		sg_finish_rem_req(sfp->headrp);
2051 
2052 	if (sfp->reserve.bufflen > 0) {
2053 		SCSI_LOG_TIMEOUT(6,
2054 			printk("sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2055 				(int) sfp->reserve.bufflen,
2056 				(int) sfp->reserve.k_use_sg));
2057 		sg_remove_scat(&sfp->reserve);
2058 	}
2059 
2060 	SCSI_LOG_TIMEOUT(6,
2061 		printk("sg_remove_sfp: %s, sfp=0x%p\n",
2062 			sdp->disk->disk_name,
2063 			sfp));
2064 	kfree(sfp);
2065 
2066 	scsi_device_put(sdp->device);
2067 	sg_put_dev(sdp);
2068 	module_put(THIS_MODULE);
2069 }
2070 
2071 static void sg_remove_sfp(struct kref *kref)
2072 {
2073 	struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2074 	struct sg_device *sdp = sfp->parentdp;
2075 	unsigned long iflags;
2076 
2077 	write_lock_irqsave(&sg_index_lock, iflags);
2078 	list_del(&sfp->sfd_siblings);
2079 	write_unlock_irqrestore(&sg_index_lock, iflags);
2080 	wake_up_interruptible(&sdp->o_excl_wait);
2081 
2082 	execute_in_process_context(sg_remove_sfp_usercontext, &sfp->ew);
2083 }
2084 
2085 static int
2086 sg_res_in_use(Sg_fd * sfp)
2087 {
2088 	const Sg_request *srp;
2089 	unsigned long iflags;
2090 
2091 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2092 	for (srp = sfp->headrp; srp; srp = srp->nextrp)
2093 		if (srp->res_used)
2094 			break;
2095 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2096 	return srp ? 1 : 0;
2097 }
2098 
2099 #ifdef CONFIG_SCSI_PROC_FS
2100 static int
2101 sg_idr_max_id(int id, void *p, void *data)
2102 {
2103 	int *k = data;
2104 
2105 	if (*k < id)
2106 		*k = id;
2107 
2108 	return 0;
2109 }
2110 
2111 static int
2112 sg_last_dev(void)
2113 {
2114 	int k = -1;
2115 	unsigned long iflags;
2116 
2117 	read_lock_irqsave(&sg_index_lock, iflags);
2118 	idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2119 	read_unlock_irqrestore(&sg_index_lock, iflags);
2120 	return k + 1;		/* origin 1 */
2121 }
2122 #endif
2123 
2124 /* must be called with sg_index_lock held */
2125 static Sg_device *sg_lookup_dev(int dev)
2126 {
2127 	return idr_find(&sg_index_idr, dev);
2128 }
2129 
2130 static Sg_device *sg_get_dev(int dev)
2131 {
2132 	struct sg_device *sdp;
2133 	unsigned long flags;
2134 
2135 	read_lock_irqsave(&sg_index_lock, flags);
2136 	sdp = sg_lookup_dev(dev);
2137 	if (!sdp)
2138 		sdp = ERR_PTR(-ENXIO);
2139 	else if (sdp->detached) {
2140 		/* If sdp->detached, then the refcount may already be 0, in
2141 		 * which case it would be a bug to do kref_get().
2142 		 */
2143 		sdp = ERR_PTR(-ENODEV);
2144 	} else
2145 		kref_get(&sdp->d_ref);
2146 	read_unlock_irqrestore(&sg_index_lock, flags);
2147 
2148 	return sdp;
2149 }
2150 
2151 static void sg_put_dev(struct sg_device *sdp)
2152 {
2153 	kref_put(&sdp->d_ref, sg_device_destroy);
2154 }
2155 
2156 #ifdef CONFIG_SCSI_PROC_FS
2157 
2158 static struct proc_dir_entry *sg_proc_sgp = NULL;
2159 
2160 static char sg_proc_sg_dirname[] = "scsi/sg";
2161 
2162 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2163 
2164 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2165 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2166 			          size_t count, loff_t *off);
2167 static struct file_operations adio_fops = {
2168 	/* .owner, .read and .llseek added in sg_proc_init() */
2169 	.open = sg_proc_single_open_adio,
2170 	.write = sg_proc_write_adio,
2171 	.release = single_release,
2172 };
2173 
2174 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2175 static ssize_t sg_proc_write_dressz(struct file *filp,
2176 		const char __user *buffer, size_t count, loff_t *off);
2177 static struct file_operations dressz_fops = {
2178 	.open = sg_proc_single_open_dressz,
2179 	.write = sg_proc_write_dressz,
2180 	.release = single_release,
2181 };
2182 
2183 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2184 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2185 static struct file_operations version_fops = {
2186 	.open = sg_proc_single_open_version,
2187 	.release = single_release,
2188 };
2189 
2190 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2191 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2192 static struct file_operations devhdr_fops = {
2193 	.open = sg_proc_single_open_devhdr,
2194 	.release = single_release,
2195 };
2196 
2197 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2198 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2199 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2200 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2201 static void dev_seq_stop(struct seq_file *s, void *v);
2202 static struct file_operations dev_fops = {
2203 	.open = sg_proc_open_dev,
2204 	.release = seq_release,
2205 };
2206 static struct seq_operations dev_seq_ops = {
2207 	.start = dev_seq_start,
2208 	.next  = dev_seq_next,
2209 	.stop  = dev_seq_stop,
2210 	.show  = sg_proc_seq_show_dev,
2211 };
2212 
2213 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2214 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2215 static struct file_operations devstrs_fops = {
2216 	.open = sg_proc_open_devstrs,
2217 	.release = seq_release,
2218 };
2219 static struct seq_operations devstrs_seq_ops = {
2220 	.start = dev_seq_start,
2221 	.next  = dev_seq_next,
2222 	.stop  = dev_seq_stop,
2223 	.show  = sg_proc_seq_show_devstrs,
2224 };
2225 
2226 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2227 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2228 static struct file_operations debug_fops = {
2229 	.open = sg_proc_open_debug,
2230 	.release = seq_release,
2231 };
2232 static struct seq_operations debug_seq_ops = {
2233 	.start = dev_seq_start,
2234 	.next  = dev_seq_next,
2235 	.stop  = dev_seq_stop,
2236 	.show  = sg_proc_seq_show_debug,
2237 };
2238 
2239 
2240 struct sg_proc_leaf {
2241 	const char * name;
2242 	struct file_operations * fops;
2243 };
2244 
2245 static struct sg_proc_leaf sg_proc_leaf_arr[] = {
2246 	{"allow_dio", &adio_fops},
2247 	{"debug", &debug_fops},
2248 	{"def_reserved_size", &dressz_fops},
2249 	{"device_hdr", &devhdr_fops},
2250 	{"devices", &dev_fops},
2251 	{"device_strs", &devstrs_fops},
2252 	{"version", &version_fops}
2253 };
2254 
2255 static int
2256 sg_proc_init(void)
2257 {
2258 	int k, mask;
2259 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2260 	struct sg_proc_leaf * leaf;
2261 
2262 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2263 	if (!sg_proc_sgp)
2264 		return 1;
2265 	for (k = 0; k < num_leaves; ++k) {
2266 		leaf = &sg_proc_leaf_arr[k];
2267 		mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2268 		leaf->fops->owner = THIS_MODULE;
2269 		leaf->fops->read = seq_read;
2270 		leaf->fops->llseek = seq_lseek;
2271 		proc_create(leaf->name, mask, sg_proc_sgp, leaf->fops);
2272 	}
2273 	return 0;
2274 }
2275 
2276 static void
2277 sg_proc_cleanup(void)
2278 {
2279 	int k;
2280 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2281 
2282 	if (!sg_proc_sgp)
2283 		return;
2284 	for (k = 0; k < num_leaves; ++k)
2285 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2286 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2287 }
2288 
2289 
2290 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2291 {
2292 	seq_printf(s, "%d\n", *((int *)s->private));
2293 	return 0;
2294 }
2295 
2296 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2297 {
2298 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2299 }
2300 
2301 static ssize_t
2302 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2303 		   size_t count, loff_t *off)
2304 {
2305 	int num;
2306 	char buff[11];
2307 
2308 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2309 		return -EACCES;
2310 	num = (count < 10) ? count : 10;
2311 	if (copy_from_user(buff, buffer, num))
2312 		return -EFAULT;
2313 	buff[num] = '\0';
2314 	sg_allow_dio = simple_strtoul(buff, NULL, 10) ? 1 : 0;
2315 	return count;
2316 }
2317 
2318 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2319 {
2320 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2321 }
2322 
2323 static ssize_t
2324 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2325 		     size_t count, loff_t *off)
2326 {
2327 	int num;
2328 	unsigned long k = ULONG_MAX;
2329 	char buff[11];
2330 
2331 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2332 		return -EACCES;
2333 	num = (count < 10) ? count : 10;
2334 	if (copy_from_user(buff, buffer, num))
2335 		return -EFAULT;
2336 	buff[num] = '\0';
2337 	k = simple_strtoul(buff, NULL, 10);
2338 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2339 		sg_big_buff = k;
2340 		return count;
2341 	}
2342 	return -ERANGE;
2343 }
2344 
2345 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2346 {
2347 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2348 		   sg_version_date);
2349 	return 0;
2350 }
2351 
2352 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2353 {
2354 	return single_open(file, sg_proc_seq_show_version, NULL);
2355 }
2356 
2357 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2358 {
2359 	seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
2360 		   "online\n");
2361 	return 0;
2362 }
2363 
2364 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2365 {
2366 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2367 }
2368 
2369 struct sg_proc_deviter {
2370 	loff_t	index;
2371 	size_t	max;
2372 };
2373 
2374 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2375 {
2376 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2377 
2378 	s->private = it;
2379 	if (! it)
2380 		return NULL;
2381 
2382 	it->index = *pos;
2383 	it->max = sg_last_dev();
2384 	if (it->index >= it->max)
2385 		return NULL;
2386 	return it;
2387 }
2388 
2389 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2390 {
2391 	struct sg_proc_deviter * it = s->private;
2392 
2393 	*pos = ++it->index;
2394 	return (it->index < it->max) ? it : NULL;
2395 }
2396 
2397 static void dev_seq_stop(struct seq_file *s, void *v)
2398 {
2399 	kfree(s->private);
2400 }
2401 
2402 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2403 {
2404         return seq_open(file, &dev_seq_ops);
2405 }
2406 
2407 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2408 {
2409 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2410 	Sg_device *sdp;
2411 	struct scsi_device *scsidp;
2412 	unsigned long iflags;
2413 
2414 	read_lock_irqsave(&sg_index_lock, iflags);
2415 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2416 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2417 		seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
2418 			      scsidp->host->host_no, scsidp->channel,
2419 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2420 			      1,
2421 			      (int) scsidp->queue_depth,
2422 			      (int) scsidp->device_busy,
2423 			      (int) scsi_device_online(scsidp));
2424 	else
2425 		seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2426 	read_unlock_irqrestore(&sg_index_lock, iflags);
2427 	return 0;
2428 }
2429 
2430 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2431 {
2432         return seq_open(file, &devstrs_seq_ops);
2433 }
2434 
2435 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2436 {
2437 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2438 	Sg_device *sdp;
2439 	struct scsi_device *scsidp;
2440 	unsigned long iflags;
2441 
2442 	read_lock_irqsave(&sg_index_lock, iflags);
2443 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2444 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2445 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2446 			   scsidp->vendor, scsidp->model, scsidp->rev);
2447 	else
2448 		seq_printf(s, "<no active device>\n");
2449 	read_unlock_irqrestore(&sg_index_lock, iflags);
2450 	return 0;
2451 }
2452 
2453 /* must be called while holding sg_index_lock */
2454 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2455 {
2456 	int k, m, new_interface, blen, usg;
2457 	Sg_request *srp;
2458 	Sg_fd *fp;
2459 	const sg_io_hdr_t *hp;
2460 	const char * cp;
2461 	unsigned int ms;
2462 
2463 	k = 0;
2464 	list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2465 		k++;
2466 		read_lock(&fp->rq_list_lock); /* irqs already disabled */
2467 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2468 			   "(res)sgat=%d low_dma=%d\n", k,
2469 			   jiffies_to_msecs(fp->timeout),
2470 			   fp->reserve.bufflen,
2471 			   (int) fp->reserve.k_use_sg,
2472 			   (int) fp->low_dma);
2473 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=%d\n",
2474 			   (int) fp->cmd_q, (int) fp->force_packid,
2475 			   (int) fp->keep_orphan, (int) fp->closed);
2476 		for (m = 0, srp = fp->headrp;
2477 				srp != NULL;
2478 				++m, srp = srp->nextrp) {
2479 			hp = &srp->header;
2480 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2481 			if (srp->res_used) {
2482 				if (new_interface &&
2483 				    (SG_FLAG_MMAP_IO & hp->flags))
2484 					cp = "     mmap>> ";
2485 				else
2486 					cp = "     rb>> ";
2487 			} else {
2488 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2489 					cp = "     dio>> ";
2490 				else
2491 					cp = "     ";
2492 			}
2493 			seq_printf(s, cp);
2494 			blen = srp->data.bufflen;
2495 			usg = srp->data.k_use_sg;
2496 			seq_printf(s, srp->done ?
2497 				   ((1 == srp->done) ?  "rcv:" : "fin:")
2498 				   : "act:");
2499 			seq_printf(s, " id=%d blen=%d",
2500 				   srp->header.pack_id, blen);
2501 			if (srp->done)
2502 				seq_printf(s, " dur=%d", hp->duration);
2503 			else {
2504 				ms = jiffies_to_msecs(jiffies);
2505 				seq_printf(s, " t_o/elap=%d/%d",
2506 					(new_interface ? hp->timeout :
2507 						  jiffies_to_msecs(fp->timeout)),
2508 					(ms > hp->duration ? ms - hp->duration : 0));
2509 			}
2510 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2511 				   (int) srp->data.cmd_opcode);
2512 		}
2513 		if (0 == m)
2514 			seq_printf(s, "     No requests active\n");
2515 		read_unlock(&fp->rq_list_lock);
2516 	}
2517 }
2518 
2519 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2520 {
2521         return seq_open(file, &debug_seq_ops);
2522 }
2523 
2524 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2525 {
2526 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2527 	Sg_device *sdp;
2528 	unsigned long iflags;
2529 
2530 	if (it && (0 == it->index)) {
2531 		seq_printf(s, "max_active_device=%d(origin 1)\n",
2532 			   (int)it->max);
2533 		seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
2534 	}
2535 
2536 	read_lock_irqsave(&sg_index_lock, iflags);
2537 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2538 	if (sdp && !list_empty(&sdp->sfds)) {
2539 		struct scsi_device *scsidp = sdp->device;
2540 
2541 		seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2542 		if (sdp->detached)
2543 			seq_printf(s, "detached pending close ");
2544 		else
2545 			seq_printf
2546 			    (s, "scsi%d chan=%d id=%d lun=%d   em=%d",
2547 			     scsidp->host->host_no,
2548 			     scsidp->channel, scsidp->id,
2549 			     scsidp->lun,
2550 			     scsidp->host->hostt->emulated);
2551 		seq_printf(s, " sg_tablesize=%d excl=%d\n",
2552 			   sdp->sg_tablesize, sdp->exclude);
2553 		sg_proc_debug_helper(s, sdp);
2554 	}
2555 	read_unlock_irqrestore(&sg_index_lock, iflags);
2556 	return 0;
2557 }
2558 
2559 #endif				/* CONFIG_SCSI_PROC_FS */
2560 
2561 module_init(init_sg);
2562 module_exit(exit_sg);
2563