xref: /openbmc/linux/drivers/scsi/sg.c (revision a8a28aff)
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/aio.h>
39 #include <linux/errno.h>
40 #include <linux/mtio.h>
41 #include <linux/ioctl.h>
42 #include <linux/slab.h>
43 #include <linux/fcntl.h>
44 #include <linux/init.h>
45 #include <linux/poll.h>
46 #include <linux/moduleparam.h>
47 #include <linux/cdev.h>
48 #include <linux/idr.h>
49 #include <linux/seq_file.h>
50 #include <linux/blkdev.h>
51 #include <linux/delay.h>
52 #include <linux/blktrace_api.h>
53 #include <linux/mutex.h>
54 #include <linux/ratelimit.h>
55 
56 #include "scsi.h"
57 #include <scsi/scsi_dbg.h>
58 #include <scsi/scsi_host.h>
59 #include <scsi/scsi_driver.h>
60 #include <scsi/scsi_ioctl.h>
61 #include <scsi/sg.h>
62 
63 #include "scsi_logging.h"
64 
65 #ifdef CONFIG_SCSI_PROC_FS
66 #include <linux/proc_fs.h>
67 static char *sg_version_date = "20061027";
68 
69 static int sg_proc_init(void);
70 static void sg_proc_cleanup(void);
71 #endif
72 
73 #define SG_ALLOW_DIO_DEF 0
74 
75 #define SG_MAX_DEVS 32768
76 
77 /*
78  * Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
79  * Then when using 32 bit integers x * m may overflow during the calculation.
80  * Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m
81  * calculates the same, but prevents the overflow when both m and d
82  * are "small" numbers (like HZ and USER_HZ).
83  * Of course an overflow is inavoidable if the result of muldiv doesn't fit
84  * in 32 bits.
85  */
86 #define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))
87 
88 #define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
89 
90 int sg_big_buff = SG_DEF_RESERVED_SIZE;
91 /* N.B. This variable is readable and writeable via
92    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
93    of this size (or less if there is not enough memory) will be reserved
94    for use by this file descriptor. [Deprecated usage: this variable is also
95    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
96    the kernel (i.e. it is not a module).] */
97 static int def_reserved_size = -1;	/* picks up init parameter */
98 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
99 
100 static int scatter_elem_sz = SG_SCATTER_SZ;
101 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
102 
103 #define SG_SECTOR_SZ 512
104 
105 static int sg_add(struct device *, struct class_interface *);
106 static void sg_remove(struct device *, struct class_interface *);
107 
108 static DEFINE_SPINLOCK(sg_open_exclusive_lock);
109 
110 static DEFINE_IDR(sg_index_idr);
111 static DEFINE_RWLOCK(sg_index_lock);	/* Also used to lock
112 							   file descriptor list for device */
113 
114 static struct class_interface sg_interface = {
115 	.add_dev	= sg_add,
116 	.remove_dev	= sg_remove,
117 };
118 
119 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
120 	unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
121 	unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
122 	unsigned bufflen;	/* Size of (aggregate) data buffer */
123 	struct page **pages;
124 	int page_order;
125 	char dio_in_use;	/* 0->indirect IO (or mmap), 1->dio */
126 	unsigned char cmd_opcode; /* first byte of command */
127 } Sg_scatter_hold;
128 
129 struct sg_device;		/* forward declarations */
130 struct sg_fd;
131 
132 typedef struct sg_request {	/* SG_MAX_QUEUE requests outstanding per file */
133 	struct sg_request *nextrp;	/* NULL -> tail request (slist) */
134 	struct sg_fd *parentfp;	/* NULL -> not in use */
135 	Sg_scatter_hold data;	/* hold buffer, perhaps scatter list */
136 	sg_io_hdr_t header;	/* scsi command+info, see <scsi/sg.h> */
137 	unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
138 	char res_used;		/* 1 -> using reserve buffer, 0 -> not ... */
139 	char orphan;		/* 1 -> drop on sight, 0 -> normal */
140 	char sg_io_owned;	/* 1 -> packet belongs to SG_IO */
141 	/* done protected by rq_list_lock */
142 	char done;		/* 0->before bh, 1->before read, 2->read */
143 	struct request *rq;
144 	struct bio *bio;
145 	struct execute_work ew;
146 } Sg_request;
147 
148 typedef struct sg_fd {		/* holds the state of a file descriptor */
149 	/* sfd_siblings is protected by sg_index_lock */
150 	struct list_head sfd_siblings;
151 	struct sg_device *parentdp;	/* owning device */
152 	wait_queue_head_t read_wait;	/* queue read until command done */
153 	rwlock_t rq_list_lock;	/* protect access to list in req_arr */
154 	int timeout;		/* defaults to SG_DEFAULT_TIMEOUT      */
155 	int timeout_user;	/* defaults to SG_DEFAULT_TIMEOUT_USER */
156 	Sg_scatter_hold reserve;	/* buffer held for this file descriptor */
157 	unsigned save_scat_len;	/* original length of trunc. scat. element */
158 	Sg_request *headrp;	/* head of request slist, NULL->empty */
159 	struct fasync_struct *async_qp;	/* used by asynchronous notification */
160 	Sg_request req_arr[SG_MAX_QUEUE];	/* used as singly-linked list */
161 	char low_dma;		/* as in parent but possibly overridden to 1 */
162 	char force_packid;	/* 1 -> pack_id input to read(), 0 -> ignored */
163 	char cmd_q;		/* 1 -> allow command queuing, 0 -> don't */
164 	char next_cmd_len;	/* 0 -> automatic (def), >0 -> use on next write() */
165 	char keep_orphan;	/* 0 -> drop orphan (def), 1 -> keep for read() */
166 	char mmap_called;	/* 0 -> mmap() never called on this fd */
167 	struct kref f_ref;
168 	struct execute_work ew;
169 } Sg_fd;
170 
171 typedef struct sg_device { /* holds the state of each scsi generic device */
172 	struct scsi_device *device;
173 	wait_queue_head_t o_excl_wait;	/* queue open() when O_EXCL in use */
174 	int sg_tablesize;	/* adapter's max scatter-gather table size */
175 	u32 index;		/* device index number */
176 	/* sfds is protected by sg_index_lock */
177 	struct list_head sfds;
178 	volatile char detached;	/* 0->attached, 1->detached pending removal */
179 	/* exclude protected by sg_open_exclusive_lock */
180 	char exclude;		/* opened for exclusive access */
181 	char sgdebug;		/* 0->off, 1->sense, 9->dump dev, 10-> all devs */
182 	struct gendisk *disk;
183 	struct cdev * cdev;	/* char_dev [sysfs: /sys/cdev/major/sg<n>] */
184 	struct kref d_ref;
185 } Sg_device;
186 
187 /* tasklet or soft irq callback */
188 static void sg_rq_end_io(struct request *rq, int uptodate);
189 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
190 static int sg_finish_rem_req(Sg_request * srp);
191 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
192 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
193 			   Sg_request * srp);
194 static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
195 			const char __user *buf, size_t count, int blocking,
196 			int read_only, int sg_io_owned, Sg_request **o_srp);
197 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
198 			   unsigned char *cmnd, int timeout, int blocking);
199 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
200 static void sg_remove_scat(Sg_scatter_hold * schp);
201 static void sg_build_reserve(Sg_fd * sfp, int req_size);
202 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
203 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
204 static Sg_fd *sg_add_sfp(Sg_device * sdp, int dev);
205 static void sg_remove_sfp(struct kref *);
206 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
207 static Sg_request *sg_add_request(Sg_fd * sfp);
208 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
209 static int sg_res_in_use(Sg_fd * sfp);
210 static Sg_device *sg_get_dev(int dev);
211 static void sg_put_dev(Sg_device *sdp);
212 
213 #define SZ_SG_HEADER sizeof(struct sg_header)
214 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
215 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
216 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
217 
218 static int sg_allow_access(struct file *filp, unsigned char *cmd)
219 {
220 	struct sg_fd *sfp = filp->private_data;
221 
222 	if (sfp->parentdp->device->type == TYPE_SCANNER)
223 		return 0;
224 
225 	return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
226 }
227 
228 static int get_exclude(Sg_device *sdp)
229 {
230 	unsigned long flags;
231 	int ret;
232 
233 	spin_lock_irqsave(&sg_open_exclusive_lock, flags);
234 	ret = sdp->exclude;
235 	spin_unlock_irqrestore(&sg_open_exclusive_lock, flags);
236 	return ret;
237 }
238 
239 static int set_exclude(Sg_device *sdp, char val)
240 {
241 	unsigned long flags;
242 
243 	spin_lock_irqsave(&sg_open_exclusive_lock, flags);
244 	sdp->exclude = val;
245 	spin_unlock_irqrestore(&sg_open_exclusive_lock, flags);
246 	return val;
247 }
248 
249 static int sfds_list_empty(Sg_device *sdp)
250 {
251 	unsigned long flags;
252 	int ret;
253 
254 	read_lock_irqsave(&sg_index_lock, flags);
255 	ret = list_empty(&sdp->sfds);
256 	read_unlock_irqrestore(&sg_index_lock, flags);
257 	return ret;
258 }
259 
260 static int
261 sg_open(struct inode *inode, struct file *filp)
262 {
263 	int dev = iminor(inode);
264 	int flags = filp->f_flags;
265 	struct request_queue *q;
266 	Sg_device *sdp;
267 	Sg_fd *sfp;
268 	int res;
269 	int retval;
270 
271 	nonseekable_open(inode, filp);
272 	SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
273 	sdp = sg_get_dev(dev);
274 	if (IS_ERR(sdp)) {
275 		retval = PTR_ERR(sdp);
276 		sdp = NULL;
277 		goto sg_put;
278 	}
279 
280 	/* This driver's module count bumped by fops_get in <linux/fs.h> */
281 	/* Prevent the device driver from vanishing while we sleep */
282 	retval = scsi_device_get(sdp->device);
283 	if (retval)
284 		goto sg_put;
285 
286 	retval = scsi_autopm_get_device(sdp->device);
287 	if (retval)
288 		goto sdp_put;
289 
290 	if (!((flags & O_NONBLOCK) ||
291 	      scsi_block_when_processing_errors(sdp->device))) {
292 		retval = -ENXIO;
293 		/* we are in error recovery for this device */
294 		goto error_out;
295 	}
296 
297 	if (flags & O_EXCL) {
298 		if (O_RDONLY == (flags & O_ACCMODE)) {
299 			retval = -EPERM; /* Can't lock it with read only access */
300 			goto error_out;
301 		}
302 		if (!sfds_list_empty(sdp) && (flags & O_NONBLOCK)) {
303 			retval = -EBUSY;
304 			goto error_out;
305 		}
306 		res = wait_event_interruptible(sdp->o_excl_wait,
307 					   ((!sfds_list_empty(sdp) || get_exclude(sdp)) ? 0 : set_exclude(sdp, 1)));
308 		if (res) {
309 			retval = res;	/* -ERESTARTSYS because signal hit process */
310 			goto error_out;
311 		}
312 	} else if (get_exclude(sdp)) {	/* some other fd has an exclusive lock on dev */
313 		if (flags & O_NONBLOCK) {
314 			retval = -EBUSY;
315 			goto error_out;
316 		}
317 		res = wait_event_interruptible(sdp->o_excl_wait, !get_exclude(sdp));
318 		if (res) {
319 			retval = res;	/* -ERESTARTSYS because signal hit process */
320 			goto error_out;
321 		}
322 	}
323 	if (sdp->detached) {
324 		retval = -ENODEV;
325 		goto error_out;
326 	}
327 	if (sfds_list_empty(sdp)) {	/* no existing opens on this device */
328 		sdp->sgdebug = 0;
329 		q = sdp->device->request_queue;
330 		sdp->sg_tablesize = queue_max_segments(q);
331 	}
332 	if ((sfp = sg_add_sfp(sdp, dev)))
333 		filp->private_data = sfp;
334 	else {
335 		if (flags & O_EXCL) {
336 			set_exclude(sdp, 0);	/* undo if error */
337 			wake_up_interruptible(&sdp->o_excl_wait);
338 		}
339 		retval = -ENOMEM;
340 		goto error_out;
341 	}
342 	retval = 0;
343 error_out:
344 	if (retval) {
345 		scsi_autopm_put_device(sdp->device);
346 sdp_put:
347 		scsi_device_put(sdp->device);
348 	}
349 sg_put:
350 	if (sdp)
351 		sg_put_dev(sdp);
352 	return retval;
353 }
354 
355 /* Following function was formerly called 'sg_close' */
356 static int
357 sg_release(struct inode *inode, struct file *filp)
358 {
359 	Sg_device *sdp;
360 	Sg_fd *sfp;
361 
362 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
363 		return -ENXIO;
364 	SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
365 
366 	set_exclude(sdp, 0);
367 	wake_up_interruptible(&sdp->o_excl_wait);
368 
369 	scsi_autopm_put_device(sdp->device);
370 	kref_put(&sfp->f_ref, sg_remove_sfp);
371 	return 0;
372 }
373 
374 static ssize_t
375 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
376 {
377 	Sg_device *sdp;
378 	Sg_fd *sfp;
379 	Sg_request *srp;
380 	int req_pack_id = -1;
381 	sg_io_hdr_t *hp;
382 	struct sg_header *old_hdr = NULL;
383 	int retval = 0;
384 
385 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
386 		return -ENXIO;
387 	SCSI_LOG_TIMEOUT(3, printk("sg_read: %s, count=%d\n",
388 				   sdp->disk->disk_name, (int) count));
389 
390 	if (!access_ok(VERIFY_WRITE, buf, count))
391 		return -EFAULT;
392 	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
393 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
394 		if (!old_hdr)
395 			return -ENOMEM;
396 		if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
397 			retval = -EFAULT;
398 			goto free_old_hdr;
399 		}
400 		if (old_hdr->reply_len < 0) {
401 			if (count >= SZ_SG_IO_HDR) {
402 				sg_io_hdr_t *new_hdr;
403 				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
404 				if (!new_hdr) {
405 					retval = -ENOMEM;
406 					goto free_old_hdr;
407 				}
408 				retval =__copy_from_user
409 				    (new_hdr, buf, SZ_SG_IO_HDR);
410 				req_pack_id = new_hdr->pack_id;
411 				kfree(new_hdr);
412 				if (retval) {
413 					retval = -EFAULT;
414 					goto free_old_hdr;
415 				}
416 			}
417 		} else
418 			req_pack_id = old_hdr->pack_id;
419 	}
420 	srp = sg_get_rq_mark(sfp, req_pack_id);
421 	if (!srp) {		/* now wait on packet to arrive */
422 		if (sdp->detached) {
423 			retval = -ENODEV;
424 			goto free_old_hdr;
425 		}
426 		if (filp->f_flags & O_NONBLOCK) {
427 			retval = -EAGAIN;
428 			goto free_old_hdr;
429 		}
430 		retval = wait_event_interruptible(sfp->read_wait,
431 			(sdp->detached ||
432 			(srp = sg_get_rq_mark(sfp, req_pack_id))));
433 		if (sdp->detached) {
434 			retval = -ENODEV;
435 			goto free_old_hdr;
436 		}
437 		if (retval) {
438 			/* -ERESTARTSYS as signal hit process */
439 			goto free_old_hdr;
440 		}
441 	}
442 	if (srp->header.interface_id != '\0') {
443 		retval = sg_new_read(sfp, buf, count, srp);
444 		goto free_old_hdr;
445 	}
446 
447 	hp = &srp->header;
448 	if (old_hdr == NULL) {
449 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
450 		if (! old_hdr) {
451 			retval = -ENOMEM;
452 			goto free_old_hdr;
453 		}
454 	}
455 	memset(old_hdr, 0, SZ_SG_HEADER);
456 	old_hdr->reply_len = (int) hp->timeout;
457 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
458 	old_hdr->pack_id = hp->pack_id;
459 	old_hdr->twelve_byte =
460 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
461 	old_hdr->target_status = hp->masked_status;
462 	old_hdr->host_status = hp->host_status;
463 	old_hdr->driver_status = hp->driver_status;
464 	if ((CHECK_CONDITION & hp->masked_status) ||
465 	    (DRIVER_SENSE & hp->driver_status))
466 		memcpy(old_hdr->sense_buffer, srp->sense_b,
467 		       sizeof (old_hdr->sense_buffer));
468 	switch (hp->host_status) {
469 	/* This setup of 'result' is for backward compatibility and is best
470 	   ignored by the user who should use target, host + driver status */
471 	case DID_OK:
472 	case DID_PASSTHROUGH:
473 	case DID_SOFT_ERROR:
474 		old_hdr->result = 0;
475 		break;
476 	case DID_NO_CONNECT:
477 	case DID_BUS_BUSY:
478 	case DID_TIME_OUT:
479 		old_hdr->result = EBUSY;
480 		break;
481 	case DID_BAD_TARGET:
482 	case DID_ABORT:
483 	case DID_PARITY:
484 	case DID_RESET:
485 	case DID_BAD_INTR:
486 		old_hdr->result = EIO;
487 		break;
488 	case DID_ERROR:
489 		old_hdr->result = (srp->sense_b[0] == 0 &&
490 				  hp->masked_status == GOOD) ? 0 : EIO;
491 		break;
492 	default:
493 		old_hdr->result = EIO;
494 		break;
495 	}
496 
497 	/* Now copy the result back to the user buffer.  */
498 	if (count >= SZ_SG_HEADER) {
499 		if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
500 			retval = -EFAULT;
501 			goto free_old_hdr;
502 		}
503 		buf += SZ_SG_HEADER;
504 		if (count > old_hdr->reply_len)
505 			count = old_hdr->reply_len;
506 		if (count > SZ_SG_HEADER) {
507 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
508 				retval = -EFAULT;
509 				goto free_old_hdr;
510 			}
511 		}
512 	} else
513 		count = (old_hdr->result == 0) ? 0 : -EIO;
514 	sg_finish_rem_req(srp);
515 	retval = count;
516 free_old_hdr:
517 	kfree(old_hdr);
518 	return retval;
519 }
520 
521 static ssize_t
522 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
523 {
524 	sg_io_hdr_t *hp = &srp->header;
525 	int err = 0;
526 	int len;
527 
528 	if (count < SZ_SG_IO_HDR) {
529 		err = -EINVAL;
530 		goto err_out;
531 	}
532 	hp->sb_len_wr = 0;
533 	if ((hp->mx_sb_len > 0) && hp->sbp) {
534 		if ((CHECK_CONDITION & hp->masked_status) ||
535 		    (DRIVER_SENSE & hp->driver_status)) {
536 			int sb_len = SCSI_SENSE_BUFFERSIZE;
537 			sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
538 			len = 8 + (int) srp->sense_b[7];	/* Additional sense length field */
539 			len = (len > sb_len) ? sb_len : len;
540 			if (copy_to_user(hp->sbp, srp->sense_b, len)) {
541 				err = -EFAULT;
542 				goto err_out;
543 			}
544 			hp->sb_len_wr = len;
545 		}
546 	}
547 	if (hp->masked_status || hp->host_status || hp->driver_status)
548 		hp->info |= SG_INFO_CHECK;
549 	if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
550 		err = -EFAULT;
551 		goto err_out;
552 	}
553 err_out:
554 	err = sg_finish_rem_req(srp);
555 	return (0 == err) ? count : err;
556 }
557 
558 static ssize_t
559 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
560 {
561 	int mxsize, cmd_size, k;
562 	int input_size, blocking;
563 	unsigned char opcode;
564 	Sg_device *sdp;
565 	Sg_fd *sfp;
566 	Sg_request *srp;
567 	struct sg_header old_hdr;
568 	sg_io_hdr_t *hp;
569 	unsigned char cmnd[MAX_COMMAND_SIZE];
570 
571 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
572 		return -ENXIO;
573 	SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n",
574 				   sdp->disk->disk_name, (int) count));
575 	if (sdp->detached)
576 		return -ENODEV;
577 	if (!((filp->f_flags & O_NONBLOCK) ||
578 	      scsi_block_when_processing_errors(sdp->device)))
579 		return -ENXIO;
580 
581 	if (!access_ok(VERIFY_READ, buf, count))
582 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
583 	if (count < SZ_SG_HEADER)
584 		return -EIO;
585 	if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
586 		return -EFAULT;
587 	blocking = !(filp->f_flags & O_NONBLOCK);
588 	if (old_hdr.reply_len < 0)
589 		return sg_new_write(sfp, filp, buf, count,
590 				    blocking, 0, 0, NULL);
591 	if (count < (SZ_SG_HEADER + 6))
592 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
593 
594 	if (!(srp = sg_add_request(sfp))) {
595 		SCSI_LOG_TIMEOUT(1, printk("sg_write: queue full\n"));
596 		return -EDOM;
597 	}
598 	buf += SZ_SG_HEADER;
599 	__get_user(opcode, buf);
600 	if (sfp->next_cmd_len > 0) {
601 		if (sfp->next_cmd_len > MAX_COMMAND_SIZE) {
602 			SCSI_LOG_TIMEOUT(1, printk("sg_write: command length too long\n"));
603 			sfp->next_cmd_len = 0;
604 			sg_remove_request(sfp, srp);
605 			return -EIO;
606 		}
607 		cmd_size = sfp->next_cmd_len;
608 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
609 	} else {
610 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
611 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
612 			cmd_size = 12;
613 	}
614 	SCSI_LOG_TIMEOUT(4, printk(
615 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
616 /* Determine buffer size.  */
617 	input_size = count - cmd_size;
618 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
619 	mxsize -= SZ_SG_HEADER;
620 	input_size -= SZ_SG_HEADER;
621 	if (input_size < 0) {
622 		sg_remove_request(sfp, srp);
623 		return -EIO;	/* User did not pass enough bytes for this command. */
624 	}
625 	hp = &srp->header;
626 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
627 	hp->cmd_len = (unsigned char) cmd_size;
628 	hp->iovec_count = 0;
629 	hp->mx_sb_len = 0;
630 	if (input_size > 0)
631 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
632 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
633 	else
634 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
635 	hp->dxfer_len = mxsize;
636 	if (hp->dxfer_direction == SG_DXFER_TO_DEV)
637 		hp->dxferp = (char __user *)buf + cmd_size;
638 	else
639 		hp->dxferp = NULL;
640 	hp->sbp = NULL;
641 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
642 	hp->flags = input_size;	/* structure abuse ... */
643 	hp->pack_id = old_hdr.pack_id;
644 	hp->usr_ptr = NULL;
645 	if (__copy_from_user(cmnd, buf, cmd_size))
646 		return -EFAULT;
647 	/*
648 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
649 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
650 	 * is a non-zero input_size, so emit a warning.
651 	 */
652 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
653 		static char cmd[TASK_COMM_LEN];
654 		if (strcmp(current->comm, cmd)) {
655 			printk_ratelimited(KERN_WARNING
656 					   "sg_write: data in/out %d/%d bytes "
657 					   "for SCSI command 0x%x-- guessing "
658 					   "data in;\n   program %s not setting "
659 					   "count and/or reply_len properly\n",
660 					   old_hdr.reply_len - (int)SZ_SG_HEADER,
661 					   input_size, (unsigned int) cmnd[0],
662 					   current->comm);
663 			strcpy(cmd, current->comm);
664 		}
665 	}
666 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
667 	return (k < 0) ? k : count;
668 }
669 
670 static ssize_t
671 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
672 		 size_t count, int blocking, int read_only, int sg_io_owned,
673 		 Sg_request **o_srp)
674 {
675 	int k;
676 	Sg_request *srp;
677 	sg_io_hdr_t *hp;
678 	unsigned char cmnd[MAX_COMMAND_SIZE];
679 	int timeout;
680 	unsigned long ul_timeout;
681 
682 	if (count < SZ_SG_IO_HDR)
683 		return -EINVAL;
684 	if (!access_ok(VERIFY_READ, buf, count))
685 		return -EFAULT; /* protects following copy_from_user()s + get_user()s */
686 
687 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
688 	if (!(srp = sg_add_request(sfp))) {
689 		SCSI_LOG_TIMEOUT(1, printk("sg_new_write: queue full\n"));
690 		return -EDOM;
691 	}
692 	srp->sg_io_owned = sg_io_owned;
693 	hp = &srp->header;
694 	if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
695 		sg_remove_request(sfp, srp);
696 		return -EFAULT;
697 	}
698 	if (hp->interface_id != 'S') {
699 		sg_remove_request(sfp, srp);
700 		return -ENOSYS;
701 	}
702 	if (hp->flags & SG_FLAG_MMAP_IO) {
703 		if (hp->dxfer_len > sfp->reserve.bufflen) {
704 			sg_remove_request(sfp, srp);
705 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
706 		}
707 		if (hp->flags & SG_FLAG_DIRECT_IO) {
708 			sg_remove_request(sfp, srp);
709 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
710 		}
711 		if (sg_res_in_use(sfp)) {
712 			sg_remove_request(sfp, srp);
713 			return -EBUSY;	/* reserve buffer already being used */
714 		}
715 	}
716 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
717 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
718 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
719 		sg_remove_request(sfp, srp);
720 		return -EMSGSIZE;
721 	}
722 	if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
723 		sg_remove_request(sfp, srp);
724 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
725 	}
726 	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
727 		sg_remove_request(sfp, srp);
728 		return -EFAULT;
729 	}
730 	if (read_only && sg_allow_access(file, cmnd)) {
731 		sg_remove_request(sfp, srp);
732 		return -EPERM;
733 	}
734 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
735 	if (k < 0)
736 		return k;
737 	if (o_srp)
738 		*o_srp = srp;
739 	return count;
740 }
741 
742 static int
743 sg_common_write(Sg_fd * sfp, Sg_request * srp,
744 		unsigned char *cmnd, int timeout, int blocking)
745 {
746 	int k, data_dir;
747 	Sg_device *sdp = sfp->parentdp;
748 	sg_io_hdr_t *hp = &srp->header;
749 
750 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
751 	hp->status = 0;
752 	hp->masked_status = 0;
753 	hp->msg_status = 0;
754 	hp->info = 0;
755 	hp->host_status = 0;
756 	hp->driver_status = 0;
757 	hp->resid = 0;
758 	SCSI_LOG_TIMEOUT(4, printk("sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
759 			  (int) cmnd[0], (int) hp->cmd_len));
760 
761 	k = sg_start_req(srp, cmnd);
762 	if (k) {
763 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: start_req err=%d\n", k));
764 		sg_finish_rem_req(srp);
765 		return k;	/* probably out of space --> ENOMEM */
766 	}
767 	if (sdp->detached) {
768 		if (srp->bio)
769 			blk_end_request_all(srp->rq, -EIO);
770 		sg_finish_rem_req(srp);
771 		return -ENODEV;
772 	}
773 
774 	switch (hp->dxfer_direction) {
775 	case SG_DXFER_TO_FROM_DEV:
776 	case SG_DXFER_FROM_DEV:
777 		data_dir = DMA_FROM_DEVICE;
778 		break;
779 	case SG_DXFER_TO_DEV:
780 		data_dir = DMA_TO_DEVICE;
781 		break;
782 	case SG_DXFER_UNKNOWN:
783 		data_dir = DMA_BIDIRECTIONAL;
784 		break;
785 	default:
786 		data_dir = DMA_NONE;
787 		break;
788 	}
789 	hp->duration = jiffies_to_msecs(jiffies);
790 
791 	srp->rq->timeout = timeout;
792 	kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
793 	blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
794 			      srp->rq, 1, sg_rq_end_io);
795 	return 0;
796 }
797 
798 static int srp_done(Sg_fd *sfp, Sg_request *srp)
799 {
800 	unsigned long flags;
801 	int ret;
802 
803 	read_lock_irqsave(&sfp->rq_list_lock, flags);
804 	ret = srp->done;
805 	read_unlock_irqrestore(&sfp->rq_list_lock, flags);
806 	return ret;
807 }
808 
809 static long
810 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
811 {
812 	void __user *p = (void __user *)arg;
813 	int __user *ip = p;
814 	int result, val, read_only;
815 	Sg_device *sdp;
816 	Sg_fd *sfp;
817 	Sg_request *srp;
818 	unsigned long iflags;
819 
820 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
821 		return -ENXIO;
822 
823 	SCSI_LOG_TIMEOUT(3, printk("sg_ioctl: %s, cmd=0x%x\n",
824 				   sdp->disk->disk_name, (int) cmd_in));
825 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
826 
827 	switch (cmd_in) {
828 	case SG_IO:
829 		if (sdp->detached)
830 			return -ENODEV;
831 		if (!scsi_block_when_processing_errors(sdp->device))
832 			return -ENXIO;
833 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
834 			return -EFAULT;
835 		result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
836 				 1, read_only, 1, &srp);
837 		if (result < 0)
838 			return result;
839 		result = wait_event_interruptible(sfp->read_wait,
840 			(srp_done(sfp, srp) || sdp->detached));
841 		if (sdp->detached)
842 			return -ENODEV;
843 		write_lock_irq(&sfp->rq_list_lock);
844 		if (srp->done) {
845 			srp->done = 2;
846 			write_unlock_irq(&sfp->rq_list_lock);
847 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
848 			return (result < 0) ? result : 0;
849 		}
850 		srp->orphan = 1;
851 		write_unlock_irq(&sfp->rq_list_lock);
852 		return result;	/* -ERESTARTSYS because signal hit process */
853 	case SG_SET_TIMEOUT:
854 		result = get_user(val, ip);
855 		if (result)
856 			return result;
857 		if (val < 0)
858 			return -EIO;
859 		if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
860 		    val = MULDIV (INT_MAX, USER_HZ, HZ);
861 		sfp->timeout_user = val;
862 		sfp->timeout = MULDIV (val, HZ, USER_HZ);
863 
864 		return 0;
865 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
866 				/* strange ..., for backward compatibility */
867 		return sfp->timeout_user;
868 	case SG_SET_FORCE_LOW_DMA:
869 		result = get_user(val, ip);
870 		if (result)
871 			return result;
872 		if (val) {
873 			sfp->low_dma = 1;
874 			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
875 				val = (int) sfp->reserve.bufflen;
876 				sg_remove_scat(&sfp->reserve);
877 				sg_build_reserve(sfp, val);
878 			}
879 		} else {
880 			if (sdp->detached)
881 				return -ENODEV;
882 			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
883 		}
884 		return 0;
885 	case SG_GET_LOW_DMA:
886 		return put_user((int) sfp->low_dma, ip);
887 	case SG_GET_SCSI_ID:
888 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
889 			return -EFAULT;
890 		else {
891 			sg_scsi_id_t __user *sg_idp = p;
892 
893 			if (sdp->detached)
894 				return -ENODEV;
895 			__put_user((int) sdp->device->host->host_no,
896 				   &sg_idp->host_no);
897 			__put_user((int) sdp->device->channel,
898 				   &sg_idp->channel);
899 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
900 			__put_user((int) sdp->device->lun, &sg_idp->lun);
901 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
902 			__put_user((short) sdp->device->host->cmd_per_lun,
903 				   &sg_idp->h_cmd_per_lun);
904 			__put_user((short) sdp->device->queue_depth,
905 				   &sg_idp->d_queue_depth);
906 			__put_user(0, &sg_idp->unused[0]);
907 			__put_user(0, &sg_idp->unused[1]);
908 			return 0;
909 		}
910 	case SG_SET_FORCE_PACK_ID:
911 		result = get_user(val, ip);
912 		if (result)
913 			return result;
914 		sfp->force_packid = val ? 1 : 0;
915 		return 0;
916 	case SG_GET_PACK_ID:
917 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
918 			return -EFAULT;
919 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
920 		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
921 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
922 				read_unlock_irqrestore(&sfp->rq_list_lock,
923 						       iflags);
924 				__put_user(srp->header.pack_id, ip);
925 				return 0;
926 			}
927 		}
928 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
929 		__put_user(-1, ip);
930 		return 0;
931 	case SG_GET_NUM_WAITING:
932 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
933 		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
934 			if ((1 == srp->done) && (!srp->sg_io_owned))
935 				++val;
936 		}
937 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
938 		return put_user(val, ip);
939 	case SG_GET_SG_TABLESIZE:
940 		return put_user(sdp->sg_tablesize, ip);
941 	case SG_SET_RESERVED_SIZE:
942 		result = get_user(val, ip);
943 		if (result)
944 			return result;
945                 if (val < 0)
946                         return -EINVAL;
947 		val = min_t(int, val,
948 			    queue_max_sectors(sdp->device->request_queue) * 512);
949 		if (val != sfp->reserve.bufflen) {
950 			if (sg_res_in_use(sfp) || sfp->mmap_called)
951 				return -EBUSY;
952 			sg_remove_scat(&sfp->reserve);
953 			sg_build_reserve(sfp, val);
954 		}
955 		return 0;
956 	case SG_GET_RESERVED_SIZE:
957 		val = min_t(int, sfp->reserve.bufflen,
958 			    queue_max_sectors(sdp->device->request_queue) * 512);
959 		return put_user(val, ip);
960 	case SG_SET_COMMAND_Q:
961 		result = get_user(val, ip);
962 		if (result)
963 			return result;
964 		sfp->cmd_q = val ? 1 : 0;
965 		return 0;
966 	case SG_GET_COMMAND_Q:
967 		return put_user((int) sfp->cmd_q, ip);
968 	case SG_SET_KEEP_ORPHAN:
969 		result = get_user(val, ip);
970 		if (result)
971 			return result;
972 		sfp->keep_orphan = val;
973 		return 0;
974 	case SG_GET_KEEP_ORPHAN:
975 		return put_user((int) sfp->keep_orphan, ip);
976 	case SG_NEXT_CMD_LEN:
977 		result = get_user(val, ip);
978 		if (result)
979 			return result;
980 		sfp->next_cmd_len = (val > 0) ? val : 0;
981 		return 0;
982 	case SG_GET_VERSION_NUM:
983 		return put_user(sg_version_num, ip);
984 	case SG_GET_ACCESS_COUNT:
985 		/* faked - we don't have a real access count anymore */
986 		val = (sdp->device ? 1 : 0);
987 		return put_user(val, ip);
988 	case SG_GET_REQUEST_TABLE:
989 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
990 			return -EFAULT;
991 		else {
992 			sg_req_info_t *rinfo;
993 			unsigned int ms;
994 
995 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
996 								GFP_KERNEL);
997 			if (!rinfo)
998 				return -ENOMEM;
999 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
1000 			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
1001 			     ++val, srp = srp ? srp->nextrp : srp) {
1002 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
1003 				if (srp) {
1004 					rinfo[val].req_state = srp->done + 1;
1005 					rinfo[val].problem =
1006 					    srp->header.masked_status &
1007 					    srp->header.host_status &
1008 					    srp->header.driver_status;
1009 					if (srp->done)
1010 						rinfo[val].duration =
1011 							srp->header.duration;
1012 					else {
1013 						ms = jiffies_to_msecs(jiffies);
1014 						rinfo[val].duration =
1015 						    (ms > srp->header.duration) ?
1016 						    (ms - srp->header.duration) : 0;
1017 					}
1018 					rinfo[val].orphan = srp->orphan;
1019 					rinfo[val].sg_io_owned =
1020 							srp->sg_io_owned;
1021 					rinfo[val].pack_id =
1022 							srp->header.pack_id;
1023 					rinfo[val].usr_ptr =
1024 							srp->header.usr_ptr;
1025 				}
1026 			}
1027 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1028 			result = __copy_to_user(p, rinfo,
1029 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1030 			result = result ? -EFAULT : 0;
1031 			kfree(rinfo);
1032 			return result;
1033 		}
1034 	case SG_EMULATED_HOST:
1035 		if (sdp->detached)
1036 			return -ENODEV;
1037 		return put_user(sdp->device->host->hostt->emulated, ip);
1038 	case SG_SCSI_RESET:
1039 		if (sdp->detached)
1040 			return -ENODEV;
1041 		if (filp->f_flags & O_NONBLOCK) {
1042 			if (scsi_host_in_recovery(sdp->device->host))
1043 				return -EBUSY;
1044 		} else if (!scsi_block_when_processing_errors(sdp->device))
1045 			return -EBUSY;
1046 		result = get_user(val, ip);
1047 		if (result)
1048 			return result;
1049 		if (SG_SCSI_RESET_NOTHING == val)
1050 			return 0;
1051 		switch (val) {
1052 		case SG_SCSI_RESET_DEVICE:
1053 			val = SCSI_TRY_RESET_DEVICE;
1054 			break;
1055 		case SG_SCSI_RESET_TARGET:
1056 			val = SCSI_TRY_RESET_TARGET;
1057 			break;
1058 		case SG_SCSI_RESET_BUS:
1059 			val = SCSI_TRY_RESET_BUS;
1060 			break;
1061 		case SG_SCSI_RESET_HOST:
1062 			val = SCSI_TRY_RESET_HOST;
1063 			break;
1064 		default:
1065 			return -EINVAL;
1066 		}
1067 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1068 			return -EACCES;
1069 		return (scsi_reset_provider(sdp->device, val) ==
1070 			SUCCESS) ? 0 : -EIO;
1071 	case SCSI_IOCTL_SEND_COMMAND:
1072 		if (sdp->detached)
1073 			return -ENODEV;
1074 		if (read_only) {
1075 			unsigned char opcode = WRITE_6;
1076 			Scsi_Ioctl_Command __user *siocp = p;
1077 
1078 			if (copy_from_user(&opcode, siocp->data, 1))
1079 				return -EFAULT;
1080 			if (sg_allow_access(filp, &opcode))
1081 				return -EPERM;
1082 		}
1083 		return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1084 	case SG_SET_DEBUG:
1085 		result = get_user(val, ip);
1086 		if (result)
1087 			return result;
1088 		sdp->sgdebug = (char) val;
1089 		return 0;
1090 	case SCSI_IOCTL_GET_IDLUN:
1091 	case SCSI_IOCTL_GET_BUS_NUMBER:
1092 	case SCSI_IOCTL_PROBE_HOST:
1093 	case SG_GET_TRANSFORM:
1094 		if (sdp->detached)
1095 			return -ENODEV;
1096 		return scsi_ioctl(sdp->device, cmd_in, p);
1097 	case BLKSECTGET:
1098 		return put_user(queue_max_sectors(sdp->device->request_queue) * 512,
1099 				ip);
1100 	case BLKTRACESETUP:
1101 		return blk_trace_setup(sdp->device->request_queue,
1102 				       sdp->disk->disk_name,
1103 				       MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1104 				       NULL,
1105 				       (char *)arg);
1106 	case BLKTRACESTART:
1107 		return blk_trace_startstop(sdp->device->request_queue, 1);
1108 	case BLKTRACESTOP:
1109 		return blk_trace_startstop(sdp->device->request_queue, 0);
1110 	case BLKTRACETEARDOWN:
1111 		return blk_trace_remove(sdp->device->request_queue);
1112 	default:
1113 		if (read_only)
1114 			return -EPERM;	/* don't know so take safe approach */
1115 		return scsi_ioctl(sdp->device, cmd_in, p);
1116 	}
1117 }
1118 
1119 #ifdef CONFIG_COMPAT
1120 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1121 {
1122 	Sg_device *sdp;
1123 	Sg_fd *sfp;
1124 	struct scsi_device *sdev;
1125 
1126 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1127 		return -ENXIO;
1128 
1129 	sdev = sdp->device;
1130 	if (sdev->host->hostt->compat_ioctl) {
1131 		int ret;
1132 
1133 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1134 
1135 		return ret;
1136 	}
1137 
1138 	return -ENOIOCTLCMD;
1139 }
1140 #endif
1141 
1142 static unsigned int
1143 sg_poll(struct file *filp, poll_table * wait)
1144 {
1145 	unsigned int res = 0;
1146 	Sg_device *sdp;
1147 	Sg_fd *sfp;
1148 	Sg_request *srp;
1149 	int count = 0;
1150 	unsigned long iflags;
1151 
1152 	sfp = filp->private_data;
1153 	if (!sfp)
1154 		return POLLERR;
1155 	sdp = sfp->parentdp;
1156 	if (!sdp)
1157 		return POLLERR;
1158 	poll_wait(filp, &sfp->read_wait, wait);
1159 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1160 	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1161 		/* if any read waiting, flag it */
1162 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1163 			res = POLLIN | POLLRDNORM;
1164 		++count;
1165 	}
1166 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1167 
1168 	if (sdp->detached)
1169 		res |= POLLHUP;
1170 	else if (!sfp->cmd_q) {
1171 		if (0 == count)
1172 			res |= POLLOUT | POLLWRNORM;
1173 	} else if (count < SG_MAX_QUEUE)
1174 		res |= POLLOUT | POLLWRNORM;
1175 	SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
1176 				   sdp->disk->disk_name, (int) res));
1177 	return res;
1178 }
1179 
1180 static int
1181 sg_fasync(int fd, struct file *filp, int mode)
1182 {
1183 	Sg_device *sdp;
1184 	Sg_fd *sfp;
1185 
1186 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1187 		return -ENXIO;
1188 	SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
1189 				   sdp->disk->disk_name, mode));
1190 
1191 	return fasync_helper(fd, filp, mode, &sfp->async_qp);
1192 }
1193 
1194 static int
1195 sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1196 {
1197 	Sg_fd *sfp;
1198 	unsigned long offset, len, sa;
1199 	Sg_scatter_hold *rsv_schp;
1200 	int k, length;
1201 
1202 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1203 		return VM_FAULT_SIGBUS;
1204 	rsv_schp = &sfp->reserve;
1205 	offset = vmf->pgoff << PAGE_SHIFT;
1206 	if (offset >= rsv_schp->bufflen)
1207 		return VM_FAULT_SIGBUS;
1208 	SCSI_LOG_TIMEOUT(3, printk("sg_vma_fault: offset=%lu, scatg=%d\n",
1209 				   offset, rsv_schp->k_use_sg));
1210 	sa = vma->vm_start;
1211 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1212 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1213 		len = vma->vm_end - sa;
1214 		len = (len < length) ? len : length;
1215 		if (offset < len) {
1216 			struct page *page = nth_page(rsv_schp->pages[k],
1217 						     offset >> PAGE_SHIFT);
1218 			get_page(page);	/* increment page count */
1219 			vmf->page = page;
1220 			return 0; /* success */
1221 		}
1222 		sa += len;
1223 		offset -= len;
1224 	}
1225 
1226 	return VM_FAULT_SIGBUS;
1227 }
1228 
1229 static const struct vm_operations_struct sg_mmap_vm_ops = {
1230 	.fault = sg_vma_fault,
1231 };
1232 
1233 static int
1234 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1235 {
1236 	Sg_fd *sfp;
1237 	unsigned long req_sz, len, sa;
1238 	Sg_scatter_hold *rsv_schp;
1239 	int k, length;
1240 
1241 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1242 		return -ENXIO;
1243 	req_sz = vma->vm_end - vma->vm_start;
1244 	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
1245 				   (void *) vma->vm_start, (int) req_sz));
1246 	if (vma->vm_pgoff)
1247 		return -EINVAL;	/* want no offset */
1248 	rsv_schp = &sfp->reserve;
1249 	if (req_sz > rsv_schp->bufflen)
1250 		return -ENOMEM;	/* cannot map more than reserved buffer */
1251 
1252 	sa = vma->vm_start;
1253 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1254 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1255 		len = vma->vm_end - sa;
1256 		len = (len < length) ? len : length;
1257 		sa += len;
1258 	}
1259 
1260 	sfp->mmap_called = 1;
1261 	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
1262 	vma->vm_private_data = sfp;
1263 	vma->vm_ops = &sg_mmap_vm_ops;
1264 	return 0;
1265 }
1266 
1267 static void sg_rq_end_io_usercontext(struct work_struct *work)
1268 {
1269 	struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1270 	struct sg_fd *sfp = srp->parentfp;
1271 
1272 	sg_finish_rem_req(srp);
1273 	kref_put(&sfp->f_ref, sg_remove_sfp);
1274 }
1275 
1276 /*
1277  * This function is a "bottom half" handler that is called by the mid
1278  * level when a command is completed (or has failed).
1279  */
1280 static void sg_rq_end_io(struct request *rq, int uptodate)
1281 {
1282 	struct sg_request *srp = rq->end_io_data;
1283 	Sg_device *sdp;
1284 	Sg_fd *sfp;
1285 	unsigned long iflags;
1286 	unsigned int ms;
1287 	char *sense;
1288 	int result, resid, done = 1;
1289 
1290 	if (WARN_ON(srp->done != 0))
1291 		return;
1292 
1293 	sfp = srp->parentfp;
1294 	if (WARN_ON(sfp == NULL))
1295 		return;
1296 
1297 	sdp = sfp->parentdp;
1298 	if (unlikely(sdp->detached))
1299 		printk(KERN_INFO "sg_rq_end_io: device detached\n");
1300 
1301 	sense = rq->sense;
1302 	result = rq->errors;
1303 	resid = rq->resid_len;
1304 
1305 	SCSI_LOG_TIMEOUT(4, printk("sg_cmd_done: %s, pack_id=%d, res=0x%x\n",
1306 		sdp->disk->disk_name, srp->header.pack_id, result));
1307 	srp->header.resid = resid;
1308 	ms = jiffies_to_msecs(jiffies);
1309 	srp->header.duration = (ms > srp->header.duration) ?
1310 				(ms - srp->header.duration) : 0;
1311 	if (0 != result) {
1312 		struct scsi_sense_hdr sshdr;
1313 
1314 		srp->header.status = 0xff & result;
1315 		srp->header.masked_status = status_byte(result);
1316 		srp->header.msg_status = msg_byte(result);
1317 		srp->header.host_status = host_byte(result);
1318 		srp->header.driver_status = driver_byte(result);
1319 		if ((sdp->sgdebug > 0) &&
1320 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1321 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1322 			__scsi_print_sense("sg_cmd_done", sense,
1323 					   SCSI_SENSE_BUFFERSIZE);
1324 
1325 		/* Following if statement is a patch supplied by Eric Youngdale */
1326 		if (driver_byte(result) != 0
1327 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1328 		    && !scsi_sense_is_deferred(&sshdr)
1329 		    && sshdr.sense_key == UNIT_ATTENTION
1330 		    && sdp->device->removable) {
1331 			/* Detected possible disc change. Set the bit - this */
1332 			/* may be used if there are filesystems using this device */
1333 			sdp->device->changed = 1;
1334 		}
1335 	}
1336 	/* Rely on write phase to clean out srp status values, so no "else" */
1337 
1338 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1339 	if (unlikely(srp->orphan)) {
1340 		if (sfp->keep_orphan)
1341 			srp->sg_io_owned = 0;
1342 		else
1343 			done = 0;
1344 	}
1345 	srp->done = done;
1346 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1347 
1348 	if (likely(done)) {
1349 		/* Now wake up any sg_read() that is waiting for this
1350 		 * packet.
1351 		 */
1352 		wake_up_interruptible(&sfp->read_wait);
1353 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1354 		kref_put(&sfp->f_ref, sg_remove_sfp);
1355 	} else {
1356 		INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1357 		schedule_work(&srp->ew.work);
1358 	}
1359 }
1360 
1361 static const struct file_operations sg_fops = {
1362 	.owner = THIS_MODULE,
1363 	.read = sg_read,
1364 	.write = sg_write,
1365 	.poll = sg_poll,
1366 	.unlocked_ioctl = sg_ioctl,
1367 #ifdef CONFIG_COMPAT
1368 	.compat_ioctl = sg_compat_ioctl,
1369 #endif
1370 	.open = sg_open,
1371 	.mmap = sg_mmap,
1372 	.release = sg_release,
1373 	.fasync = sg_fasync,
1374 	.llseek = no_llseek,
1375 };
1376 
1377 static struct class *sg_sysfs_class;
1378 
1379 static int sg_sysfs_valid = 0;
1380 
1381 static Sg_device *sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1382 {
1383 	struct request_queue *q = scsidp->request_queue;
1384 	Sg_device *sdp;
1385 	unsigned long iflags;
1386 	int error;
1387 	u32 k;
1388 
1389 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1390 	if (!sdp) {
1391 		printk(KERN_WARNING "kmalloc Sg_device failure\n");
1392 		return ERR_PTR(-ENOMEM);
1393 	}
1394 
1395 	idr_preload(GFP_KERNEL);
1396 	write_lock_irqsave(&sg_index_lock, iflags);
1397 
1398 	error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
1399 	if (error < 0) {
1400 		if (error == -ENOSPC) {
1401 			sdev_printk(KERN_WARNING, scsidp,
1402 				    "Unable to attach sg device type=%d, minor number exceeds %d\n",
1403 				    scsidp->type, SG_MAX_DEVS - 1);
1404 			error = -ENODEV;
1405 		} else {
1406 			printk(KERN_WARNING
1407 			       "idr allocation Sg_device failure: %d\n", error);
1408 		}
1409 		goto out_unlock;
1410 	}
1411 	k = error;
1412 
1413 	SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
1414 	sprintf(disk->disk_name, "sg%d", k);
1415 	disk->first_minor = k;
1416 	sdp->disk = disk;
1417 	sdp->device = scsidp;
1418 	INIT_LIST_HEAD(&sdp->sfds);
1419 	init_waitqueue_head(&sdp->o_excl_wait);
1420 	sdp->sg_tablesize = queue_max_segments(q);
1421 	sdp->index = k;
1422 	kref_init(&sdp->d_ref);
1423 	error = 0;
1424 
1425 out_unlock:
1426 	write_unlock_irqrestore(&sg_index_lock, iflags);
1427 	idr_preload_end();
1428 
1429 	if (error) {
1430 		kfree(sdp);
1431 		return ERR_PTR(error);
1432 	}
1433 	return sdp;
1434 }
1435 
1436 static int
1437 sg_add(struct device *cl_dev, struct class_interface *cl_intf)
1438 {
1439 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1440 	struct gendisk *disk;
1441 	Sg_device *sdp = NULL;
1442 	struct cdev * cdev = NULL;
1443 	int error;
1444 	unsigned long iflags;
1445 
1446 	disk = alloc_disk(1);
1447 	if (!disk) {
1448 		printk(KERN_WARNING "alloc_disk failed\n");
1449 		return -ENOMEM;
1450 	}
1451 	disk->major = SCSI_GENERIC_MAJOR;
1452 
1453 	error = -ENOMEM;
1454 	cdev = cdev_alloc();
1455 	if (!cdev) {
1456 		printk(KERN_WARNING "cdev_alloc failed\n");
1457 		goto out;
1458 	}
1459 	cdev->owner = THIS_MODULE;
1460 	cdev->ops = &sg_fops;
1461 
1462 	sdp = sg_alloc(disk, scsidp);
1463 	if (IS_ERR(sdp)) {
1464 		printk(KERN_WARNING "sg_alloc failed\n");
1465 		error = PTR_ERR(sdp);
1466 		goto out;
1467 	}
1468 
1469 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1470 	if (error)
1471 		goto cdev_add_err;
1472 
1473 	sdp->cdev = cdev;
1474 	if (sg_sysfs_valid) {
1475 		struct device *sg_class_member;
1476 
1477 		sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1478 						MKDEV(SCSI_GENERIC_MAJOR,
1479 						      sdp->index),
1480 						sdp, "%s", disk->disk_name);
1481 		if (IS_ERR(sg_class_member)) {
1482 			printk(KERN_ERR "sg_add: "
1483 			       "device_create failed\n");
1484 			error = PTR_ERR(sg_class_member);
1485 			goto cdev_add_err;
1486 		}
1487 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1488 					  &sg_class_member->kobj, "generic");
1489 		if (error)
1490 			printk(KERN_ERR "sg_add: unable to make symlink "
1491 					"'generic' back to sg%d\n", sdp->index);
1492 	} else
1493 		printk(KERN_WARNING "sg_add: sg_sys Invalid\n");
1494 
1495 	sdev_printk(KERN_NOTICE, scsidp,
1496 		    "Attached scsi generic sg%d type %d\n", sdp->index,
1497 		    scsidp->type);
1498 
1499 	dev_set_drvdata(cl_dev, sdp);
1500 
1501 	return 0;
1502 
1503 cdev_add_err:
1504 	write_lock_irqsave(&sg_index_lock, iflags);
1505 	idr_remove(&sg_index_idr, sdp->index);
1506 	write_unlock_irqrestore(&sg_index_lock, iflags);
1507 	kfree(sdp);
1508 
1509 out:
1510 	put_disk(disk);
1511 	if (cdev)
1512 		cdev_del(cdev);
1513 	return error;
1514 }
1515 
1516 static void sg_device_destroy(struct kref *kref)
1517 {
1518 	struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1519 	unsigned long flags;
1520 
1521 	/* CAUTION!  Note that the device can still be found via idr_find()
1522 	 * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1523 	 * any other cleanup.
1524 	 */
1525 
1526 	write_lock_irqsave(&sg_index_lock, flags);
1527 	idr_remove(&sg_index_idr, sdp->index);
1528 	write_unlock_irqrestore(&sg_index_lock, flags);
1529 
1530 	SCSI_LOG_TIMEOUT(3,
1531 		printk("sg_device_destroy: %s\n",
1532 			sdp->disk->disk_name));
1533 
1534 	put_disk(sdp->disk);
1535 	kfree(sdp);
1536 }
1537 
1538 static void sg_remove(struct device *cl_dev, struct class_interface *cl_intf)
1539 {
1540 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1541 	Sg_device *sdp = dev_get_drvdata(cl_dev);
1542 	unsigned long iflags;
1543 	Sg_fd *sfp;
1544 
1545 	if (!sdp || sdp->detached)
1546 		return;
1547 
1548 	SCSI_LOG_TIMEOUT(3, printk("sg_remove: %s\n", sdp->disk->disk_name));
1549 
1550 	/* Need a write lock to set sdp->detached. */
1551 	write_lock_irqsave(&sg_index_lock, iflags);
1552 	sdp->detached = 1;
1553 	list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1554 		wake_up_interruptible(&sfp->read_wait);
1555 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1556 	}
1557 	write_unlock_irqrestore(&sg_index_lock, iflags);
1558 
1559 	sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1560 	device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1561 	cdev_del(sdp->cdev);
1562 	sdp->cdev = NULL;
1563 
1564 	sg_put_dev(sdp);
1565 }
1566 
1567 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1568 module_param_named(def_reserved_size, def_reserved_size, int,
1569 		   S_IRUGO | S_IWUSR);
1570 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1571 
1572 MODULE_AUTHOR("Douglas Gilbert");
1573 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1574 MODULE_LICENSE("GPL");
1575 MODULE_VERSION(SG_VERSION_STR);
1576 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1577 
1578 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1579                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1580 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1581 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1582 
1583 static int __init
1584 init_sg(void)
1585 {
1586 	int rc;
1587 
1588 	if (scatter_elem_sz < PAGE_SIZE) {
1589 		scatter_elem_sz = PAGE_SIZE;
1590 		scatter_elem_sz_prev = scatter_elem_sz;
1591 	}
1592 	if (def_reserved_size >= 0)
1593 		sg_big_buff = def_reserved_size;
1594 	else
1595 		def_reserved_size = sg_big_buff;
1596 
1597 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1598 				    SG_MAX_DEVS, "sg");
1599 	if (rc)
1600 		return rc;
1601         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1602         if ( IS_ERR(sg_sysfs_class) ) {
1603 		rc = PTR_ERR(sg_sysfs_class);
1604 		goto err_out;
1605         }
1606 	sg_sysfs_valid = 1;
1607 	rc = scsi_register_interface(&sg_interface);
1608 	if (0 == rc) {
1609 #ifdef CONFIG_SCSI_PROC_FS
1610 		sg_proc_init();
1611 #endif				/* CONFIG_SCSI_PROC_FS */
1612 		return 0;
1613 	}
1614 	class_destroy(sg_sysfs_class);
1615 err_out:
1616 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1617 	return rc;
1618 }
1619 
1620 static void __exit
1621 exit_sg(void)
1622 {
1623 #ifdef CONFIG_SCSI_PROC_FS
1624 	sg_proc_cleanup();
1625 #endif				/* CONFIG_SCSI_PROC_FS */
1626 	scsi_unregister_interface(&sg_interface);
1627 	class_destroy(sg_sysfs_class);
1628 	sg_sysfs_valid = 0;
1629 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1630 				 SG_MAX_DEVS);
1631 	idr_destroy(&sg_index_idr);
1632 }
1633 
1634 static int sg_start_req(Sg_request *srp, unsigned char *cmd)
1635 {
1636 	int res;
1637 	struct request *rq;
1638 	Sg_fd *sfp = srp->parentfp;
1639 	sg_io_hdr_t *hp = &srp->header;
1640 	int dxfer_len = (int) hp->dxfer_len;
1641 	int dxfer_dir = hp->dxfer_direction;
1642 	unsigned int iov_count = hp->iovec_count;
1643 	Sg_scatter_hold *req_schp = &srp->data;
1644 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1645 	struct request_queue *q = sfp->parentdp->device->request_queue;
1646 	struct rq_map_data *md, map_data;
1647 	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1648 
1649 	SCSI_LOG_TIMEOUT(4, printk(KERN_INFO "sg_start_req: dxfer_len=%d\n",
1650 				   dxfer_len));
1651 
1652 	rq = blk_get_request(q, rw, GFP_ATOMIC);
1653 	if (!rq)
1654 		return -ENOMEM;
1655 
1656 	blk_rq_set_block_pc(rq);
1657 	memcpy(rq->cmd, cmd, hp->cmd_len);
1658 	rq->cmd_len = hp->cmd_len;
1659 
1660 	srp->rq = rq;
1661 	rq->end_io_data = srp;
1662 	rq->sense = srp->sense_b;
1663 	rq->retries = SG_DEFAULT_RETRIES;
1664 
1665 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1666 		return 0;
1667 
1668 	if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1669 	    dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1670 	    !sfp->parentdp->device->host->unchecked_isa_dma &&
1671 	    blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1672 		md = NULL;
1673 	else
1674 		md = &map_data;
1675 
1676 	if (md) {
1677 		if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
1678 			sg_link_reserve(sfp, srp, dxfer_len);
1679 		else {
1680 			res = sg_build_indirect(req_schp, sfp, dxfer_len);
1681 			if (res)
1682 				return res;
1683 		}
1684 
1685 		md->pages = req_schp->pages;
1686 		md->page_order = req_schp->page_order;
1687 		md->nr_entries = req_schp->k_use_sg;
1688 		md->offset = 0;
1689 		md->null_mapped = hp->dxferp ? 0 : 1;
1690 		if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1691 			md->from_user = 1;
1692 		else
1693 			md->from_user = 0;
1694 	}
1695 
1696 	if (iov_count) {
1697 		int len, size = sizeof(struct sg_iovec) * iov_count;
1698 		struct iovec *iov;
1699 
1700 		iov = memdup_user(hp->dxferp, size);
1701 		if (IS_ERR(iov))
1702 			return PTR_ERR(iov);
1703 
1704 		len = iov_length(iov, iov_count);
1705 		if (hp->dxfer_len < len) {
1706 			iov_count = iov_shorten(iov, iov_count, hp->dxfer_len);
1707 			len = hp->dxfer_len;
1708 		}
1709 
1710 		res = blk_rq_map_user_iov(q, rq, md, (struct sg_iovec *)iov,
1711 					  iov_count,
1712 					  len, GFP_ATOMIC);
1713 		kfree(iov);
1714 	} else
1715 		res = blk_rq_map_user(q, rq, md, hp->dxferp,
1716 				      hp->dxfer_len, GFP_ATOMIC);
1717 
1718 	if (!res) {
1719 		srp->bio = rq->bio;
1720 
1721 		if (!md) {
1722 			req_schp->dio_in_use = 1;
1723 			hp->info |= SG_INFO_DIRECT_IO;
1724 		}
1725 	}
1726 	return res;
1727 }
1728 
1729 static int sg_finish_rem_req(Sg_request * srp)
1730 {
1731 	int ret = 0;
1732 
1733 	Sg_fd *sfp = srp->parentfp;
1734 	Sg_scatter_hold *req_schp = &srp->data;
1735 
1736 	SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
1737 	if (srp->rq) {
1738 		if (srp->bio)
1739 			ret = blk_rq_unmap_user(srp->bio);
1740 
1741 		blk_put_request(srp->rq);
1742 	}
1743 
1744 	if (srp->res_used)
1745 		sg_unlink_reserve(sfp, srp);
1746 	else
1747 		sg_remove_scat(req_schp);
1748 
1749 	sg_remove_request(sfp, srp);
1750 
1751 	return ret;
1752 }
1753 
1754 static int
1755 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1756 {
1757 	int sg_bufflen = tablesize * sizeof(struct page *);
1758 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1759 
1760 	schp->pages = kzalloc(sg_bufflen, gfp_flags);
1761 	if (!schp->pages)
1762 		return -ENOMEM;
1763 	schp->sglist_len = sg_bufflen;
1764 	return tablesize;	/* number of scat_gath elements allocated */
1765 }
1766 
1767 static int
1768 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1769 {
1770 	int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1771 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1772 	int blk_size = buff_size, order;
1773 	gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
1774 
1775 	if (blk_size < 0)
1776 		return -EFAULT;
1777 	if (0 == blk_size)
1778 		++blk_size;	/* don't know why */
1779 	/* round request up to next highest SG_SECTOR_SZ byte boundary */
1780 	blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1781 	SCSI_LOG_TIMEOUT(4, printk("sg_build_indirect: buff_size=%d, blk_size=%d\n",
1782 				   buff_size, blk_size));
1783 
1784 	/* N.B. ret_sz carried into this block ... */
1785 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1786 	if (mx_sc_elems < 0)
1787 		return mx_sc_elems;	/* most likely -ENOMEM */
1788 
1789 	num = scatter_elem_sz;
1790 	if (unlikely(num != scatter_elem_sz_prev)) {
1791 		if (num < PAGE_SIZE) {
1792 			scatter_elem_sz = PAGE_SIZE;
1793 			scatter_elem_sz_prev = PAGE_SIZE;
1794 		} else
1795 			scatter_elem_sz_prev = num;
1796 	}
1797 
1798 	if (sfp->low_dma)
1799 		gfp_mask |= GFP_DMA;
1800 
1801 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1802 		gfp_mask |= __GFP_ZERO;
1803 
1804 	order = get_order(num);
1805 retry:
1806 	ret_sz = 1 << (PAGE_SHIFT + order);
1807 
1808 	for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1809 	     k++, rem_sz -= ret_sz) {
1810 
1811 		num = (rem_sz > scatter_elem_sz_prev) ?
1812 			scatter_elem_sz_prev : rem_sz;
1813 
1814 		schp->pages[k] = alloc_pages(gfp_mask, order);
1815 		if (!schp->pages[k])
1816 			goto out;
1817 
1818 		if (num == scatter_elem_sz_prev) {
1819 			if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1820 				scatter_elem_sz = ret_sz;
1821 				scatter_elem_sz_prev = ret_sz;
1822 			}
1823 		}
1824 
1825 		SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k=%d, num=%d, "
1826 				 "ret_sz=%d\n", k, num, ret_sz));
1827 	}		/* end of for loop */
1828 
1829 	schp->page_order = order;
1830 	schp->k_use_sg = k;
1831 	SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, "
1832 			 "rem_sz=%d\n", k, rem_sz));
1833 
1834 	schp->bufflen = blk_size;
1835 	if (rem_sz > 0)	/* must have failed */
1836 		return -ENOMEM;
1837 	return 0;
1838 out:
1839 	for (i = 0; i < k; i++)
1840 		__free_pages(schp->pages[i], order);
1841 
1842 	if (--order >= 0)
1843 		goto retry;
1844 
1845 	return -ENOMEM;
1846 }
1847 
1848 static void
1849 sg_remove_scat(Sg_scatter_hold * schp)
1850 {
1851 	SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1852 	if (schp->pages && schp->sglist_len > 0) {
1853 		if (!schp->dio_in_use) {
1854 			int k;
1855 
1856 			for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1857 				SCSI_LOG_TIMEOUT(5, printk(
1858 				    "sg_remove_scat: k=%d, pg=0x%p\n",
1859 				    k, schp->pages[k]));
1860 				__free_pages(schp->pages[k], schp->page_order);
1861 			}
1862 
1863 			kfree(schp->pages);
1864 		}
1865 	}
1866 	memset(schp, 0, sizeof (*schp));
1867 }
1868 
1869 static int
1870 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1871 {
1872 	Sg_scatter_hold *schp = &srp->data;
1873 	int k, num;
1874 
1875 	SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n",
1876 				   num_read_xfer));
1877 	if ((!outp) || (num_read_xfer <= 0))
1878 		return 0;
1879 
1880 	num = 1 << (PAGE_SHIFT + schp->page_order);
1881 	for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1882 		if (num > num_read_xfer) {
1883 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1884 					   num_read_xfer))
1885 				return -EFAULT;
1886 			break;
1887 		} else {
1888 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1889 					   num))
1890 				return -EFAULT;
1891 			num_read_xfer -= num;
1892 			if (num_read_xfer <= 0)
1893 				break;
1894 			outp += num;
1895 		}
1896 	}
1897 
1898 	return 0;
1899 }
1900 
1901 static void
1902 sg_build_reserve(Sg_fd * sfp, int req_size)
1903 {
1904 	Sg_scatter_hold *schp = &sfp->reserve;
1905 
1906 	SCSI_LOG_TIMEOUT(4, printk("sg_build_reserve: req_size=%d\n", req_size));
1907 	do {
1908 		if (req_size < PAGE_SIZE)
1909 			req_size = PAGE_SIZE;
1910 		if (0 == sg_build_indirect(schp, sfp, req_size))
1911 			return;
1912 		else
1913 			sg_remove_scat(schp);
1914 		req_size >>= 1;	/* divide by 2 */
1915 	} while (req_size > (PAGE_SIZE / 2));
1916 }
1917 
1918 static void
1919 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
1920 {
1921 	Sg_scatter_hold *req_schp = &srp->data;
1922 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1923 	int k, num, rem;
1924 
1925 	srp->res_used = 1;
1926 	SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
1927 	rem = size;
1928 
1929 	num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1930 	for (k = 0; k < rsv_schp->k_use_sg; k++) {
1931 		if (rem <= num) {
1932 			req_schp->k_use_sg = k + 1;
1933 			req_schp->sglist_len = rsv_schp->sglist_len;
1934 			req_schp->pages = rsv_schp->pages;
1935 
1936 			req_schp->bufflen = size;
1937 			req_schp->page_order = rsv_schp->page_order;
1938 			break;
1939 		} else
1940 			rem -= num;
1941 	}
1942 
1943 	if (k >= rsv_schp->k_use_sg)
1944 		SCSI_LOG_TIMEOUT(1, printk("sg_link_reserve: BAD size\n"));
1945 }
1946 
1947 static void
1948 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
1949 {
1950 	Sg_scatter_hold *req_schp = &srp->data;
1951 
1952 	SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n",
1953 				   (int) req_schp->k_use_sg));
1954 	req_schp->k_use_sg = 0;
1955 	req_schp->bufflen = 0;
1956 	req_schp->pages = NULL;
1957 	req_schp->page_order = 0;
1958 	req_schp->sglist_len = 0;
1959 	sfp->save_scat_len = 0;
1960 	srp->res_used = 0;
1961 }
1962 
1963 static Sg_request *
1964 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
1965 {
1966 	Sg_request *resp;
1967 	unsigned long iflags;
1968 
1969 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1970 	for (resp = sfp->headrp; resp; resp = resp->nextrp) {
1971 		/* look for requests that are ready + not SG_IO owned */
1972 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
1973 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
1974 			resp->done = 2;	/* guard against other readers */
1975 			break;
1976 		}
1977 	}
1978 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1979 	return resp;
1980 }
1981 
1982 /* always adds to end of list */
1983 static Sg_request *
1984 sg_add_request(Sg_fd * sfp)
1985 {
1986 	int k;
1987 	unsigned long iflags;
1988 	Sg_request *resp;
1989 	Sg_request *rp = sfp->req_arr;
1990 
1991 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1992 	resp = sfp->headrp;
1993 	if (!resp) {
1994 		memset(rp, 0, sizeof (Sg_request));
1995 		rp->parentfp = sfp;
1996 		resp = rp;
1997 		sfp->headrp = resp;
1998 	} else {
1999 		if (0 == sfp->cmd_q)
2000 			resp = NULL;	/* command queuing disallowed */
2001 		else {
2002 			for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2003 				if (!rp->parentfp)
2004 					break;
2005 			}
2006 			if (k < SG_MAX_QUEUE) {
2007 				memset(rp, 0, sizeof (Sg_request));
2008 				rp->parentfp = sfp;
2009 				while (resp->nextrp)
2010 					resp = resp->nextrp;
2011 				resp->nextrp = rp;
2012 				resp = rp;
2013 			} else
2014 				resp = NULL;
2015 		}
2016 	}
2017 	if (resp) {
2018 		resp->nextrp = NULL;
2019 		resp->header.duration = jiffies_to_msecs(jiffies);
2020 	}
2021 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2022 	return resp;
2023 }
2024 
2025 /* Return of 1 for found; 0 for not found */
2026 static int
2027 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2028 {
2029 	Sg_request *prev_rp;
2030 	Sg_request *rp;
2031 	unsigned long iflags;
2032 	int res = 0;
2033 
2034 	if ((!sfp) || (!srp) || (!sfp->headrp))
2035 		return res;
2036 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2037 	prev_rp = sfp->headrp;
2038 	if (srp == prev_rp) {
2039 		sfp->headrp = prev_rp->nextrp;
2040 		prev_rp->parentfp = NULL;
2041 		res = 1;
2042 	} else {
2043 		while ((rp = prev_rp->nextrp)) {
2044 			if (srp == rp) {
2045 				prev_rp->nextrp = rp->nextrp;
2046 				rp->parentfp = NULL;
2047 				res = 1;
2048 				break;
2049 			}
2050 			prev_rp = rp;
2051 		}
2052 	}
2053 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2054 	return res;
2055 }
2056 
2057 static Sg_fd *
2058 sg_add_sfp(Sg_device * sdp, int dev)
2059 {
2060 	Sg_fd *sfp;
2061 	unsigned long iflags;
2062 	int bufflen;
2063 
2064 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2065 	if (!sfp)
2066 		return NULL;
2067 
2068 	init_waitqueue_head(&sfp->read_wait);
2069 	rwlock_init(&sfp->rq_list_lock);
2070 
2071 	kref_init(&sfp->f_ref);
2072 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2073 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2074 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2075 	sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2076 	    sdp->device->host->unchecked_isa_dma : 1;
2077 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2078 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2079 	sfp->parentdp = sdp;
2080 	write_lock_irqsave(&sg_index_lock, iflags);
2081 	list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2082 	write_unlock_irqrestore(&sg_index_lock, iflags);
2083 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
2084 	if (unlikely(sg_big_buff != def_reserved_size))
2085 		sg_big_buff = def_reserved_size;
2086 
2087 	bufflen = min_t(int, sg_big_buff,
2088 			queue_max_sectors(sdp->device->request_queue) * 512);
2089 	sg_build_reserve(sfp, bufflen);
2090 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp:   bufflen=%d, k_use_sg=%d\n",
2091 			   sfp->reserve.bufflen, sfp->reserve.k_use_sg));
2092 
2093 	kref_get(&sdp->d_ref);
2094 	__module_get(THIS_MODULE);
2095 	return sfp;
2096 }
2097 
2098 static void sg_remove_sfp_usercontext(struct work_struct *work)
2099 {
2100 	struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2101 	struct sg_device *sdp = sfp->parentdp;
2102 
2103 	/* Cleanup any responses which were never read(). */
2104 	while (sfp->headrp)
2105 		sg_finish_rem_req(sfp->headrp);
2106 
2107 	if (sfp->reserve.bufflen > 0) {
2108 		SCSI_LOG_TIMEOUT(6,
2109 			printk("sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2110 				(int) sfp->reserve.bufflen,
2111 				(int) sfp->reserve.k_use_sg));
2112 		sg_remove_scat(&sfp->reserve);
2113 	}
2114 
2115 	SCSI_LOG_TIMEOUT(6,
2116 		printk("sg_remove_sfp: %s, sfp=0x%p\n",
2117 			sdp->disk->disk_name,
2118 			sfp));
2119 	kfree(sfp);
2120 
2121 	scsi_device_put(sdp->device);
2122 	sg_put_dev(sdp);
2123 	module_put(THIS_MODULE);
2124 }
2125 
2126 static void sg_remove_sfp(struct kref *kref)
2127 {
2128 	struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2129 	struct sg_device *sdp = sfp->parentdp;
2130 	unsigned long iflags;
2131 
2132 	write_lock_irqsave(&sg_index_lock, iflags);
2133 	list_del(&sfp->sfd_siblings);
2134 	write_unlock_irqrestore(&sg_index_lock, iflags);
2135 	wake_up_interruptible(&sdp->o_excl_wait);
2136 
2137 	INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2138 	schedule_work(&sfp->ew.work);
2139 }
2140 
2141 static int
2142 sg_res_in_use(Sg_fd * sfp)
2143 {
2144 	const Sg_request *srp;
2145 	unsigned long iflags;
2146 
2147 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2148 	for (srp = sfp->headrp; srp; srp = srp->nextrp)
2149 		if (srp->res_used)
2150 			break;
2151 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2152 	return srp ? 1 : 0;
2153 }
2154 
2155 #ifdef CONFIG_SCSI_PROC_FS
2156 static int
2157 sg_idr_max_id(int id, void *p, void *data)
2158 {
2159 	int *k = data;
2160 
2161 	if (*k < id)
2162 		*k = id;
2163 
2164 	return 0;
2165 }
2166 
2167 static int
2168 sg_last_dev(void)
2169 {
2170 	int k = -1;
2171 	unsigned long iflags;
2172 
2173 	read_lock_irqsave(&sg_index_lock, iflags);
2174 	idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2175 	read_unlock_irqrestore(&sg_index_lock, iflags);
2176 	return k + 1;		/* origin 1 */
2177 }
2178 #endif
2179 
2180 /* must be called with sg_index_lock held */
2181 static Sg_device *sg_lookup_dev(int dev)
2182 {
2183 	return idr_find(&sg_index_idr, dev);
2184 }
2185 
2186 static Sg_device *sg_get_dev(int dev)
2187 {
2188 	struct sg_device *sdp;
2189 	unsigned long flags;
2190 
2191 	read_lock_irqsave(&sg_index_lock, flags);
2192 	sdp = sg_lookup_dev(dev);
2193 	if (!sdp)
2194 		sdp = ERR_PTR(-ENXIO);
2195 	else if (sdp->detached) {
2196 		/* If sdp->detached, then the refcount may already be 0, in
2197 		 * which case it would be a bug to do kref_get().
2198 		 */
2199 		sdp = ERR_PTR(-ENODEV);
2200 	} else
2201 		kref_get(&sdp->d_ref);
2202 	read_unlock_irqrestore(&sg_index_lock, flags);
2203 
2204 	return sdp;
2205 }
2206 
2207 static void sg_put_dev(struct sg_device *sdp)
2208 {
2209 	kref_put(&sdp->d_ref, sg_device_destroy);
2210 }
2211 
2212 #ifdef CONFIG_SCSI_PROC_FS
2213 
2214 static struct proc_dir_entry *sg_proc_sgp = NULL;
2215 
2216 static char sg_proc_sg_dirname[] = "scsi/sg";
2217 
2218 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2219 
2220 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2221 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2222 			          size_t count, loff_t *off);
2223 static const struct file_operations adio_fops = {
2224 	.owner = THIS_MODULE,
2225 	.open = sg_proc_single_open_adio,
2226 	.read = seq_read,
2227 	.llseek = seq_lseek,
2228 	.write = sg_proc_write_adio,
2229 	.release = single_release,
2230 };
2231 
2232 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2233 static ssize_t sg_proc_write_dressz(struct file *filp,
2234 		const char __user *buffer, size_t count, loff_t *off);
2235 static const struct file_operations dressz_fops = {
2236 	.owner = THIS_MODULE,
2237 	.open = sg_proc_single_open_dressz,
2238 	.read = seq_read,
2239 	.llseek = seq_lseek,
2240 	.write = sg_proc_write_dressz,
2241 	.release = single_release,
2242 };
2243 
2244 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2245 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2246 static const struct file_operations version_fops = {
2247 	.owner = THIS_MODULE,
2248 	.open = sg_proc_single_open_version,
2249 	.read = seq_read,
2250 	.llseek = seq_lseek,
2251 	.release = single_release,
2252 };
2253 
2254 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2255 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2256 static const struct file_operations devhdr_fops = {
2257 	.owner = THIS_MODULE,
2258 	.open = sg_proc_single_open_devhdr,
2259 	.read = seq_read,
2260 	.llseek = seq_lseek,
2261 	.release = single_release,
2262 };
2263 
2264 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2265 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2266 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2267 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2268 static void dev_seq_stop(struct seq_file *s, void *v);
2269 static const struct file_operations dev_fops = {
2270 	.owner = THIS_MODULE,
2271 	.open = sg_proc_open_dev,
2272 	.read = seq_read,
2273 	.llseek = seq_lseek,
2274 	.release = seq_release,
2275 };
2276 static const struct seq_operations dev_seq_ops = {
2277 	.start = dev_seq_start,
2278 	.next  = dev_seq_next,
2279 	.stop  = dev_seq_stop,
2280 	.show  = sg_proc_seq_show_dev,
2281 };
2282 
2283 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2284 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2285 static const struct file_operations devstrs_fops = {
2286 	.owner = THIS_MODULE,
2287 	.open = sg_proc_open_devstrs,
2288 	.read = seq_read,
2289 	.llseek = seq_lseek,
2290 	.release = seq_release,
2291 };
2292 static const struct seq_operations devstrs_seq_ops = {
2293 	.start = dev_seq_start,
2294 	.next  = dev_seq_next,
2295 	.stop  = dev_seq_stop,
2296 	.show  = sg_proc_seq_show_devstrs,
2297 };
2298 
2299 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2300 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2301 static const struct file_operations debug_fops = {
2302 	.owner = THIS_MODULE,
2303 	.open = sg_proc_open_debug,
2304 	.read = seq_read,
2305 	.llseek = seq_lseek,
2306 	.release = seq_release,
2307 };
2308 static const struct seq_operations debug_seq_ops = {
2309 	.start = dev_seq_start,
2310 	.next  = dev_seq_next,
2311 	.stop  = dev_seq_stop,
2312 	.show  = sg_proc_seq_show_debug,
2313 };
2314 
2315 
2316 struct sg_proc_leaf {
2317 	const char * name;
2318 	const struct file_operations * fops;
2319 };
2320 
2321 static const struct sg_proc_leaf sg_proc_leaf_arr[] = {
2322 	{"allow_dio", &adio_fops},
2323 	{"debug", &debug_fops},
2324 	{"def_reserved_size", &dressz_fops},
2325 	{"device_hdr", &devhdr_fops},
2326 	{"devices", &dev_fops},
2327 	{"device_strs", &devstrs_fops},
2328 	{"version", &version_fops}
2329 };
2330 
2331 static int
2332 sg_proc_init(void)
2333 {
2334 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2335 	int k;
2336 
2337 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2338 	if (!sg_proc_sgp)
2339 		return 1;
2340 	for (k = 0; k < num_leaves; ++k) {
2341 		const struct sg_proc_leaf *leaf = &sg_proc_leaf_arr[k];
2342 		umode_t mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2343 		proc_create(leaf->name, mask, sg_proc_sgp, leaf->fops);
2344 	}
2345 	return 0;
2346 }
2347 
2348 static void
2349 sg_proc_cleanup(void)
2350 {
2351 	int k;
2352 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2353 
2354 	if (!sg_proc_sgp)
2355 		return;
2356 	for (k = 0; k < num_leaves; ++k)
2357 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2358 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2359 }
2360 
2361 
2362 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2363 {
2364 	seq_printf(s, "%d\n", *((int *)s->private));
2365 	return 0;
2366 }
2367 
2368 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2369 {
2370 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2371 }
2372 
2373 static ssize_t
2374 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2375 		   size_t count, loff_t *off)
2376 {
2377 	int err;
2378 	unsigned long num;
2379 
2380 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2381 		return -EACCES;
2382 	err = kstrtoul_from_user(buffer, count, 0, &num);
2383 	if (err)
2384 		return err;
2385 	sg_allow_dio = num ? 1 : 0;
2386 	return count;
2387 }
2388 
2389 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2390 {
2391 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2392 }
2393 
2394 static ssize_t
2395 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2396 		     size_t count, loff_t *off)
2397 {
2398 	int err;
2399 	unsigned long k = ULONG_MAX;
2400 
2401 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2402 		return -EACCES;
2403 
2404 	err = kstrtoul_from_user(buffer, count, 0, &k);
2405 	if (err)
2406 		return err;
2407 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2408 		sg_big_buff = k;
2409 		return count;
2410 	}
2411 	return -ERANGE;
2412 }
2413 
2414 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2415 {
2416 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2417 		   sg_version_date);
2418 	return 0;
2419 }
2420 
2421 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2422 {
2423 	return single_open(file, sg_proc_seq_show_version, NULL);
2424 }
2425 
2426 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2427 {
2428 	seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
2429 		   "online\n");
2430 	return 0;
2431 }
2432 
2433 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2434 {
2435 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2436 }
2437 
2438 struct sg_proc_deviter {
2439 	loff_t	index;
2440 	size_t	max;
2441 };
2442 
2443 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2444 {
2445 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2446 
2447 	s->private = it;
2448 	if (! it)
2449 		return NULL;
2450 
2451 	it->index = *pos;
2452 	it->max = sg_last_dev();
2453 	if (it->index >= it->max)
2454 		return NULL;
2455 	return it;
2456 }
2457 
2458 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2459 {
2460 	struct sg_proc_deviter * it = s->private;
2461 
2462 	*pos = ++it->index;
2463 	return (it->index < it->max) ? it : NULL;
2464 }
2465 
2466 static void dev_seq_stop(struct seq_file *s, void *v)
2467 {
2468 	kfree(s->private);
2469 }
2470 
2471 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2472 {
2473         return seq_open(file, &dev_seq_ops);
2474 }
2475 
2476 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2477 {
2478 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2479 	Sg_device *sdp;
2480 	struct scsi_device *scsidp;
2481 	unsigned long iflags;
2482 
2483 	read_lock_irqsave(&sg_index_lock, iflags);
2484 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2485 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2486 		seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
2487 			      scsidp->host->host_no, scsidp->channel,
2488 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2489 			      1,
2490 			      (int) scsidp->queue_depth,
2491 			      (int) scsidp->device_busy,
2492 			      (int) scsi_device_online(scsidp));
2493 	else
2494 		seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2495 	read_unlock_irqrestore(&sg_index_lock, iflags);
2496 	return 0;
2497 }
2498 
2499 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2500 {
2501         return seq_open(file, &devstrs_seq_ops);
2502 }
2503 
2504 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2505 {
2506 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2507 	Sg_device *sdp;
2508 	struct scsi_device *scsidp;
2509 	unsigned long iflags;
2510 
2511 	read_lock_irqsave(&sg_index_lock, iflags);
2512 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2513 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2514 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2515 			   scsidp->vendor, scsidp->model, scsidp->rev);
2516 	else
2517 		seq_printf(s, "<no active device>\n");
2518 	read_unlock_irqrestore(&sg_index_lock, iflags);
2519 	return 0;
2520 }
2521 
2522 /* must be called while holding sg_index_lock */
2523 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2524 {
2525 	int k, m, new_interface, blen, usg;
2526 	Sg_request *srp;
2527 	Sg_fd *fp;
2528 	const sg_io_hdr_t *hp;
2529 	const char * cp;
2530 	unsigned int ms;
2531 
2532 	k = 0;
2533 	list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2534 		k++;
2535 		read_lock(&fp->rq_list_lock); /* irqs already disabled */
2536 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2537 			   "(res)sgat=%d low_dma=%d\n", k,
2538 			   jiffies_to_msecs(fp->timeout),
2539 			   fp->reserve.bufflen,
2540 			   (int) fp->reserve.k_use_sg,
2541 			   (int) fp->low_dma);
2542 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
2543 			   (int) fp->cmd_q, (int) fp->force_packid,
2544 			   (int) fp->keep_orphan);
2545 		for (m = 0, srp = fp->headrp;
2546 				srp != NULL;
2547 				++m, srp = srp->nextrp) {
2548 			hp = &srp->header;
2549 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2550 			if (srp->res_used) {
2551 				if (new_interface &&
2552 				    (SG_FLAG_MMAP_IO & hp->flags))
2553 					cp = "     mmap>> ";
2554 				else
2555 					cp = "     rb>> ";
2556 			} else {
2557 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2558 					cp = "     dio>> ";
2559 				else
2560 					cp = "     ";
2561 			}
2562 			seq_printf(s, cp);
2563 			blen = srp->data.bufflen;
2564 			usg = srp->data.k_use_sg;
2565 			seq_printf(s, srp->done ?
2566 				   ((1 == srp->done) ?  "rcv:" : "fin:")
2567 				   : "act:");
2568 			seq_printf(s, " id=%d blen=%d",
2569 				   srp->header.pack_id, blen);
2570 			if (srp->done)
2571 				seq_printf(s, " dur=%d", hp->duration);
2572 			else {
2573 				ms = jiffies_to_msecs(jiffies);
2574 				seq_printf(s, " t_o/elap=%d/%d",
2575 					(new_interface ? hp->timeout :
2576 						  jiffies_to_msecs(fp->timeout)),
2577 					(ms > hp->duration ? ms - hp->duration : 0));
2578 			}
2579 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2580 				   (int) srp->data.cmd_opcode);
2581 		}
2582 		if (0 == m)
2583 			seq_printf(s, "     No requests active\n");
2584 		read_unlock(&fp->rq_list_lock);
2585 	}
2586 }
2587 
2588 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2589 {
2590         return seq_open(file, &debug_seq_ops);
2591 }
2592 
2593 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2594 {
2595 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2596 	Sg_device *sdp;
2597 	unsigned long iflags;
2598 
2599 	if (it && (0 == it->index)) {
2600 		seq_printf(s, "max_active_device=%d(origin 1)\n",
2601 			   (int)it->max);
2602 		seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
2603 	}
2604 
2605 	read_lock_irqsave(&sg_index_lock, iflags);
2606 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2607 	if (sdp && !list_empty(&sdp->sfds)) {
2608 		struct scsi_device *scsidp = sdp->device;
2609 
2610 		seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2611 		if (sdp->detached)
2612 			seq_printf(s, "detached pending close ");
2613 		else
2614 			seq_printf
2615 			    (s, "scsi%d chan=%d id=%d lun=%d   em=%d",
2616 			     scsidp->host->host_no,
2617 			     scsidp->channel, scsidp->id,
2618 			     scsidp->lun,
2619 			     scsidp->host->hostt->emulated);
2620 		seq_printf(s, " sg_tablesize=%d excl=%d\n",
2621 			   sdp->sg_tablesize, get_exclude(sdp));
2622 		sg_proc_debug_helper(s, sdp);
2623 	}
2624 	read_unlock_irqrestore(&sg_index_lock, iflags);
2625 	return 0;
2626 }
2627 
2628 #endif				/* CONFIG_SCSI_PROC_FS */
2629 
2630 module_init(init_sg);
2631 module_exit(exit_sg);
2632