xref: /linux/drivers/scsi/sg.c (revision c1aac62f36c1e37ee81c9e09ee9ee733eef05dcb)
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 - 2014 Douglas Gilbert
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License as published by
14  * the Free Software Foundation; either version 2, or (at your option)
15  * any later version.
16  *
17  */
18 
19 static int sg_version_num = 30536;	/* 2 digits for each component */
20 #define SG_VERSION_STR "3.5.36"
21 
22 /*
23  *  D. P. Gilbert (dgilbert@interlog.com), notes:
24  *      - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
25  *        the kernel/module needs to be built with CONFIG_SCSI_LOGGING
26  *        (otherwise the macros compile to empty statements).
27  *
28  */
29 #include <linux/module.h>
30 
31 #include <linux/fs.h>
32 #include <linux/kernel.h>
33 #include <linux/sched.h>
34 #include <linux/string.h>
35 #include <linux/mm.h>
36 #include <linux/errno.h>
37 #include <linux/mtio.h>
38 #include <linux/ioctl.h>
39 #include <linux/slab.h>
40 #include <linux/fcntl.h>
41 #include <linux/init.h>
42 #include <linux/poll.h>
43 #include <linux/moduleparam.h>
44 #include <linux/cdev.h>
45 #include <linux/idr.h>
46 #include <linux/seq_file.h>
47 #include <linux/blkdev.h>
48 #include <linux/delay.h>
49 #include <linux/blktrace_api.h>
50 #include <linux/mutex.h>
51 #include <linux/atomic.h>
52 #include <linux/ratelimit.h>
53 #include <linux/uio.h>
54 
55 #include "scsi.h"
56 #include <scsi/scsi_dbg.h>
57 #include <scsi/scsi_host.h>
58 #include <scsi/scsi_driver.h>
59 #include <scsi/scsi_ioctl.h>
60 #include <scsi/sg.h>
61 
62 #include "scsi_logging.h"
63 
64 #ifdef CONFIG_SCSI_PROC_FS
65 #include <linux/proc_fs.h>
66 static char *sg_version_date = "20140603";
67 
68 static int sg_proc_init(void);
69 static void sg_proc_cleanup(void);
70 #endif
71 
72 #define SG_ALLOW_DIO_DEF 0
73 
74 #define SG_MAX_DEVS 32768
75 
76 /* SG_MAX_CDB_SIZE should be 260 (spc4r37 section 3.1.30) however the type
77  * of sg_io_hdr::cmd_len can only represent 255. All SCSI commands greater
78  * than 16 bytes are "variable length" whose length is a multiple of 4
79  */
80 #define SG_MAX_CDB_SIZE 252
81 
82 #define SG_DEFAULT_TIMEOUT mult_frac(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
83 
84 int sg_big_buff = SG_DEF_RESERVED_SIZE;
85 /* N.B. This variable is readable and writeable via
86    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
87    of this size (or less if there is not enough memory) will be reserved
88    for use by this file descriptor. [Deprecated usage: this variable is also
89    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
90    the kernel (i.e. it is not a module).] */
91 static int def_reserved_size = -1;	/* picks up init parameter */
92 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
93 
94 static int scatter_elem_sz = SG_SCATTER_SZ;
95 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
96 
97 #define SG_SECTOR_SZ 512
98 
99 static int sg_add_device(struct device *, struct class_interface *);
100 static void sg_remove_device(struct device *, struct class_interface *);
101 
102 static DEFINE_IDR(sg_index_idr);
103 static DEFINE_RWLOCK(sg_index_lock);	/* Also used to lock
104 							   file descriptor list for device */
105 
106 static struct class_interface sg_interface = {
107 	.add_dev        = sg_add_device,
108 	.remove_dev     = sg_remove_device,
109 };
110 
111 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
112 	unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
113 	unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
114 	unsigned bufflen;	/* Size of (aggregate) data buffer */
115 	struct page **pages;
116 	int page_order;
117 	char dio_in_use;	/* 0->indirect IO (or mmap), 1->dio */
118 	unsigned char cmd_opcode; /* first byte of command */
119 } Sg_scatter_hold;
120 
121 struct sg_device;		/* forward declarations */
122 struct sg_fd;
123 
124 typedef struct sg_request {	/* SG_MAX_QUEUE requests outstanding per file */
125 	struct sg_request *nextrp;	/* NULL -> tail request (slist) */
126 	struct sg_fd *parentfp;	/* NULL -> not in use */
127 	Sg_scatter_hold data;	/* hold buffer, perhaps scatter list */
128 	sg_io_hdr_t header;	/* scsi command+info, see <scsi/sg.h> */
129 	unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
130 	char res_used;		/* 1 -> using reserve buffer, 0 -> not ... */
131 	char orphan;		/* 1 -> drop on sight, 0 -> normal */
132 	char sg_io_owned;	/* 1 -> packet belongs to SG_IO */
133 	/* done protected by rq_list_lock */
134 	char done;		/* 0->before bh, 1->before read, 2->read */
135 	struct request *rq;
136 	struct bio *bio;
137 	struct execute_work ew;
138 } Sg_request;
139 
140 typedef struct sg_fd {		/* holds the state of a file descriptor */
141 	struct list_head sfd_siblings;  /* protected by device's sfd_lock */
142 	struct sg_device *parentdp;	/* owning device */
143 	wait_queue_head_t read_wait;	/* queue read until command done */
144 	rwlock_t rq_list_lock;	/* protect access to list in req_arr */
145 	int timeout;		/* defaults to SG_DEFAULT_TIMEOUT      */
146 	int timeout_user;	/* defaults to SG_DEFAULT_TIMEOUT_USER */
147 	Sg_scatter_hold reserve;	/* buffer held for this file descriptor */
148 	unsigned save_scat_len;	/* original length of trunc. scat. element */
149 	Sg_request *headrp;	/* head of request slist, NULL->empty */
150 	struct fasync_struct *async_qp;	/* used by asynchronous notification */
151 	Sg_request req_arr[SG_MAX_QUEUE];	/* used as singly-linked list */
152 	char low_dma;		/* as in parent but possibly overridden to 1 */
153 	char force_packid;	/* 1 -> pack_id input to read(), 0 -> ignored */
154 	char cmd_q;		/* 1 -> allow command queuing, 0 -> don't */
155 	unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
156 	char keep_orphan;	/* 0 -> drop orphan (def), 1 -> keep for read() */
157 	char mmap_called;	/* 0 -> mmap() never called on this fd */
158 	struct kref f_ref;
159 	struct execute_work ew;
160 } Sg_fd;
161 
162 typedef struct sg_device { /* holds the state of each scsi generic device */
163 	struct scsi_device *device;
164 	wait_queue_head_t open_wait;    /* queue open() when O_EXCL present */
165 	struct mutex open_rel_lock;     /* held when in open() or release() */
166 	int sg_tablesize;	/* adapter's max scatter-gather table size */
167 	u32 index;		/* device index number */
168 	struct list_head sfds;
169 	rwlock_t sfd_lock;      /* protect access to sfd list */
170 	atomic_t detaching;     /* 0->device usable, 1->device detaching */
171 	bool exclude;		/* 1->open(O_EXCL) succeeded and is active */
172 	int open_cnt;		/* count of opens (perhaps < num(sfds) ) */
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 int 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_fd * sfp, 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);
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_device_destroy(struct kref *kref);
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 #define sg_printk(prefix, sdp, fmt, a...) \
211 	sdev_prefix_printk(prefix, (sdp)->device,		\
212 			   (sdp)->disk->disk_name, fmt, ##a)
213 
214 static int sg_allow_access(struct file *filp, unsigned char *cmd)
215 {
216 	struct sg_fd *sfp = filp->private_data;
217 
218 	if (sfp->parentdp->device->type == TYPE_SCANNER)
219 		return 0;
220 
221 	return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
222 }
223 
224 static int
225 open_wait(Sg_device *sdp, int flags)
226 {
227 	int retval = 0;
228 
229 	if (flags & O_EXCL) {
230 		while (sdp->open_cnt > 0) {
231 			mutex_unlock(&sdp->open_rel_lock);
232 			retval = wait_event_interruptible(sdp->open_wait,
233 					(atomic_read(&sdp->detaching) ||
234 					 !sdp->open_cnt));
235 			mutex_lock(&sdp->open_rel_lock);
236 
237 			if (retval) /* -ERESTARTSYS */
238 				return retval;
239 			if (atomic_read(&sdp->detaching))
240 				return -ENODEV;
241 		}
242 	} else {
243 		while (sdp->exclude) {
244 			mutex_unlock(&sdp->open_rel_lock);
245 			retval = wait_event_interruptible(sdp->open_wait,
246 					(atomic_read(&sdp->detaching) ||
247 					 !sdp->exclude));
248 			mutex_lock(&sdp->open_rel_lock);
249 
250 			if (retval) /* -ERESTARTSYS */
251 				return retval;
252 			if (atomic_read(&sdp->detaching))
253 				return -ENODEV;
254 		}
255 	}
256 
257 	return retval;
258 }
259 
260 /* Returns 0 on success, else a negated errno value */
261 static int
262 sg_open(struct inode *inode, struct file *filp)
263 {
264 	int dev = iminor(inode);
265 	int flags = filp->f_flags;
266 	struct request_queue *q;
267 	Sg_device *sdp;
268 	Sg_fd *sfp;
269 	int retval;
270 
271 	nonseekable_open(inode, filp);
272 	if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE)))
273 		return -EPERM; /* Can't lock it with read only access */
274 	sdp = sg_get_dev(dev);
275 	if (IS_ERR(sdp))
276 		return PTR_ERR(sdp);
277 
278 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
279 				      "sg_open: flags=0x%x\n", flags));
280 
281 	/* This driver's module count bumped by fops_get in <linux/fs.h> */
282 	/* Prevent the device driver from vanishing while we sleep */
283 	retval = scsi_device_get(sdp->device);
284 	if (retval)
285 		goto sg_put;
286 
287 	retval = scsi_autopm_get_device(sdp->device);
288 	if (retval)
289 		goto sdp_put;
290 
291 	/* scsi_block_when_processing_errors() may block so bypass
292 	 * check if O_NONBLOCK. Permits SCSI commands to be issued
293 	 * during error recovery. Tread carefully. */
294 	if (!((flags & O_NONBLOCK) ||
295 	      scsi_block_when_processing_errors(sdp->device))) {
296 		retval = -ENXIO;
297 		/* we are in error recovery for this device */
298 		goto error_out;
299 	}
300 
301 	mutex_lock(&sdp->open_rel_lock);
302 	if (flags & O_NONBLOCK) {
303 		if (flags & O_EXCL) {
304 			if (sdp->open_cnt > 0) {
305 				retval = -EBUSY;
306 				goto error_mutex_locked;
307 			}
308 		} else {
309 			if (sdp->exclude) {
310 				retval = -EBUSY;
311 				goto error_mutex_locked;
312 			}
313 		}
314 	} else {
315 		retval = open_wait(sdp, flags);
316 		if (retval) /* -ERESTARTSYS or -ENODEV */
317 			goto error_mutex_locked;
318 	}
319 
320 	/* N.B. at this point we are holding the open_rel_lock */
321 	if (flags & O_EXCL)
322 		sdp->exclude = true;
323 
324 	if (sdp->open_cnt < 1) {  /* no existing opens */
325 		sdp->sgdebug = 0;
326 		q = sdp->device->request_queue;
327 		sdp->sg_tablesize = queue_max_segments(q);
328 	}
329 	sfp = sg_add_sfp(sdp);
330 	if (IS_ERR(sfp)) {
331 		retval = PTR_ERR(sfp);
332 		goto out_undo;
333 	}
334 
335 	filp->private_data = sfp;
336 	sdp->open_cnt++;
337 	mutex_unlock(&sdp->open_rel_lock);
338 
339 	retval = 0;
340 sg_put:
341 	kref_put(&sdp->d_ref, sg_device_destroy);
342 	return retval;
343 
344 out_undo:
345 	if (flags & O_EXCL) {
346 		sdp->exclude = false;   /* undo if error */
347 		wake_up_interruptible(&sdp->open_wait);
348 	}
349 error_mutex_locked:
350 	mutex_unlock(&sdp->open_rel_lock);
351 error_out:
352 	scsi_autopm_put_device(sdp->device);
353 sdp_put:
354 	scsi_device_put(sdp->device);
355 	goto sg_put;
356 }
357 
358 /* Release resources associated with a successful sg_open()
359  * Returns 0 on success, else a negated errno value */
360 static int
361 sg_release(struct inode *inode, struct file *filp)
362 {
363 	Sg_device *sdp;
364 	Sg_fd *sfp;
365 
366 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
367 		return -ENXIO;
368 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n"));
369 
370 	mutex_lock(&sdp->open_rel_lock);
371 	scsi_autopm_put_device(sdp->device);
372 	kref_put(&sfp->f_ref, sg_remove_sfp);
373 	sdp->open_cnt--;
374 
375 	/* possibly many open()s waiting on exlude clearing, start many;
376 	 * only open(O_EXCL)s wait on 0==open_cnt so only start one */
377 	if (sdp->exclude) {
378 		sdp->exclude = false;
379 		wake_up_interruptible_all(&sdp->open_wait);
380 	} else if (0 == sdp->open_cnt) {
381 		wake_up_interruptible(&sdp->open_wait);
382 	}
383 	mutex_unlock(&sdp->open_rel_lock);
384 	return 0;
385 }
386 
387 static ssize_t
388 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
389 {
390 	Sg_device *sdp;
391 	Sg_fd *sfp;
392 	Sg_request *srp;
393 	int req_pack_id = -1;
394 	sg_io_hdr_t *hp;
395 	struct sg_header *old_hdr = NULL;
396 	int retval = 0;
397 
398 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
399 		return -ENXIO;
400 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
401 				      "sg_read: count=%d\n", (int) count));
402 
403 	if (!access_ok(VERIFY_WRITE, buf, count))
404 		return -EFAULT;
405 	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
406 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
407 		if (!old_hdr)
408 			return -ENOMEM;
409 		if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
410 			retval = -EFAULT;
411 			goto free_old_hdr;
412 		}
413 		if (old_hdr->reply_len < 0) {
414 			if (count >= SZ_SG_IO_HDR) {
415 				sg_io_hdr_t *new_hdr;
416 				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
417 				if (!new_hdr) {
418 					retval = -ENOMEM;
419 					goto free_old_hdr;
420 				}
421 				retval =__copy_from_user
422 				    (new_hdr, buf, SZ_SG_IO_HDR);
423 				req_pack_id = new_hdr->pack_id;
424 				kfree(new_hdr);
425 				if (retval) {
426 					retval = -EFAULT;
427 					goto free_old_hdr;
428 				}
429 			}
430 		} else
431 			req_pack_id = old_hdr->pack_id;
432 	}
433 	srp = sg_get_rq_mark(sfp, req_pack_id);
434 	if (!srp) {		/* now wait on packet to arrive */
435 		if (atomic_read(&sdp->detaching)) {
436 			retval = -ENODEV;
437 			goto free_old_hdr;
438 		}
439 		if (filp->f_flags & O_NONBLOCK) {
440 			retval = -EAGAIN;
441 			goto free_old_hdr;
442 		}
443 		retval = wait_event_interruptible(sfp->read_wait,
444 			(atomic_read(&sdp->detaching) ||
445 			(srp = sg_get_rq_mark(sfp, req_pack_id))));
446 		if (atomic_read(&sdp->detaching)) {
447 			retval = -ENODEV;
448 			goto free_old_hdr;
449 		}
450 		if (retval) {
451 			/* -ERESTARTSYS as signal hit process */
452 			goto free_old_hdr;
453 		}
454 	}
455 	if (srp->header.interface_id != '\0') {
456 		retval = sg_new_read(sfp, buf, count, srp);
457 		goto free_old_hdr;
458 	}
459 
460 	hp = &srp->header;
461 	if (old_hdr == NULL) {
462 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
463 		if (! old_hdr) {
464 			retval = -ENOMEM;
465 			goto free_old_hdr;
466 		}
467 	}
468 	memset(old_hdr, 0, SZ_SG_HEADER);
469 	old_hdr->reply_len = (int) hp->timeout;
470 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
471 	old_hdr->pack_id = hp->pack_id;
472 	old_hdr->twelve_byte =
473 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
474 	old_hdr->target_status = hp->masked_status;
475 	old_hdr->host_status = hp->host_status;
476 	old_hdr->driver_status = hp->driver_status;
477 	if ((CHECK_CONDITION & hp->masked_status) ||
478 	    (DRIVER_SENSE & hp->driver_status))
479 		memcpy(old_hdr->sense_buffer, srp->sense_b,
480 		       sizeof (old_hdr->sense_buffer));
481 	switch (hp->host_status) {
482 	/* This setup of 'result' is for backward compatibility and is best
483 	   ignored by the user who should use target, host + driver status */
484 	case DID_OK:
485 	case DID_PASSTHROUGH:
486 	case DID_SOFT_ERROR:
487 		old_hdr->result = 0;
488 		break;
489 	case DID_NO_CONNECT:
490 	case DID_BUS_BUSY:
491 	case DID_TIME_OUT:
492 		old_hdr->result = EBUSY;
493 		break;
494 	case DID_BAD_TARGET:
495 	case DID_ABORT:
496 	case DID_PARITY:
497 	case DID_RESET:
498 	case DID_BAD_INTR:
499 		old_hdr->result = EIO;
500 		break;
501 	case DID_ERROR:
502 		old_hdr->result = (srp->sense_b[0] == 0 &&
503 				  hp->masked_status == GOOD) ? 0 : EIO;
504 		break;
505 	default:
506 		old_hdr->result = EIO;
507 		break;
508 	}
509 
510 	/* Now copy the result back to the user buffer.  */
511 	if (count >= SZ_SG_HEADER) {
512 		if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
513 			retval = -EFAULT;
514 			goto free_old_hdr;
515 		}
516 		buf += SZ_SG_HEADER;
517 		if (count > old_hdr->reply_len)
518 			count = old_hdr->reply_len;
519 		if (count > SZ_SG_HEADER) {
520 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
521 				retval = -EFAULT;
522 				goto free_old_hdr;
523 			}
524 		}
525 	} else
526 		count = (old_hdr->result == 0) ? 0 : -EIO;
527 	sg_finish_rem_req(srp);
528 	retval = count;
529 free_old_hdr:
530 	kfree(old_hdr);
531 	return retval;
532 }
533 
534 static ssize_t
535 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
536 {
537 	sg_io_hdr_t *hp = &srp->header;
538 	int err = 0, err2;
539 	int len;
540 
541 	if (count < SZ_SG_IO_HDR) {
542 		err = -EINVAL;
543 		goto err_out;
544 	}
545 	hp->sb_len_wr = 0;
546 	if ((hp->mx_sb_len > 0) && hp->sbp) {
547 		if ((CHECK_CONDITION & hp->masked_status) ||
548 		    (DRIVER_SENSE & hp->driver_status)) {
549 			int sb_len = SCSI_SENSE_BUFFERSIZE;
550 			sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
551 			len = 8 + (int) srp->sense_b[7];	/* Additional sense length field */
552 			len = (len > sb_len) ? sb_len : len;
553 			if (copy_to_user(hp->sbp, srp->sense_b, len)) {
554 				err = -EFAULT;
555 				goto err_out;
556 			}
557 			hp->sb_len_wr = len;
558 		}
559 	}
560 	if (hp->masked_status || hp->host_status || hp->driver_status)
561 		hp->info |= SG_INFO_CHECK;
562 	if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
563 		err = -EFAULT;
564 		goto err_out;
565 	}
566 err_out:
567 	err2 = sg_finish_rem_req(srp);
568 	return err ? : err2 ? : count;
569 }
570 
571 static ssize_t
572 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
573 {
574 	int mxsize, cmd_size, k;
575 	int input_size, blocking;
576 	unsigned char opcode;
577 	Sg_device *sdp;
578 	Sg_fd *sfp;
579 	Sg_request *srp;
580 	struct sg_header old_hdr;
581 	sg_io_hdr_t *hp;
582 	unsigned char cmnd[SG_MAX_CDB_SIZE];
583 
584 	if (unlikely(segment_eq(get_fs(), KERNEL_DS)))
585 		return -EINVAL;
586 
587 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
588 		return -ENXIO;
589 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
590 				      "sg_write: count=%d\n", (int) count));
591 	if (atomic_read(&sdp->detaching))
592 		return -ENODEV;
593 	if (!((filp->f_flags & O_NONBLOCK) ||
594 	      scsi_block_when_processing_errors(sdp->device)))
595 		return -ENXIO;
596 
597 	if (!access_ok(VERIFY_READ, buf, count))
598 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
599 	if (count < SZ_SG_HEADER)
600 		return -EIO;
601 	if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
602 		return -EFAULT;
603 	blocking = !(filp->f_flags & O_NONBLOCK);
604 	if (old_hdr.reply_len < 0)
605 		return sg_new_write(sfp, filp, buf, count,
606 				    blocking, 0, 0, NULL);
607 	if (count < (SZ_SG_HEADER + 6))
608 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
609 
610 	if (!(srp = sg_add_request(sfp))) {
611 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sdp,
612 					      "sg_write: queue full\n"));
613 		return -EDOM;
614 	}
615 	buf += SZ_SG_HEADER;
616 	__get_user(opcode, buf);
617 	if (sfp->next_cmd_len > 0) {
618 		cmd_size = sfp->next_cmd_len;
619 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
620 	} else {
621 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
622 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
623 			cmd_size = 12;
624 	}
625 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
626 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
627 /* Determine buffer size.  */
628 	input_size = count - cmd_size;
629 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
630 	mxsize -= SZ_SG_HEADER;
631 	input_size -= SZ_SG_HEADER;
632 	if (input_size < 0) {
633 		sg_remove_request(sfp, srp);
634 		return -EIO;	/* User did not pass enough bytes for this command. */
635 	}
636 	hp = &srp->header;
637 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
638 	hp->cmd_len = (unsigned char) cmd_size;
639 	hp->iovec_count = 0;
640 	hp->mx_sb_len = 0;
641 	if (input_size > 0)
642 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
643 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
644 	else
645 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
646 	hp->dxfer_len = mxsize;
647 	if ((hp->dxfer_direction == SG_DXFER_TO_DEV) ||
648 	    (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV))
649 		hp->dxferp = (char __user *)buf + cmd_size;
650 	else
651 		hp->dxferp = NULL;
652 	hp->sbp = NULL;
653 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
654 	hp->flags = input_size;	/* structure abuse ... */
655 	hp->pack_id = old_hdr.pack_id;
656 	hp->usr_ptr = NULL;
657 	if (__copy_from_user(cmnd, buf, cmd_size))
658 		return -EFAULT;
659 	/*
660 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
661 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
662 	 * is a non-zero input_size, so emit a warning.
663 	 */
664 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
665 		static char cmd[TASK_COMM_LEN];
666 		if (strcmp(current->comm, cmd)) {
667 			printk_ratelimited(KERN_WARNING
668 					   "sg_write: data in/out %d/%d bytes "
669 					   "for SCSI command 0x%x-- guessing "
670 					   "data in;\n   program %s not setting "
671 					   "count and/or reply_len properly\n",
672 					   old_hdr.reply_len - (int)SZ_SG_HEADER,
673 					   input_size, (unsigned int) cmnd[0],
674 					   current->comm);
675 			strcpy(cmd, current->comm);
676 		}
677 	}
678 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
679 	return (k < 0) ? k : count;
680 }
681 
682 static ssize_t
683 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
684 		 size_t count, int blocking, int read_only, int sg_io_owned,
685 		 Sg_request **o_srp)
686 {
687 	int k;
688 	Sg_request *srp;
689 	sg_io_hdr_t *hp;
690 	unsigned char cmnd[SG_MAX_CDB_SIZE];
691 	int timeout;
692 	unsigned long ul_timeout;
693 
694 	if (count < SZ_SG_IO_HDR)
695 		return -EINVAL;
696 	if (!access_ok(VERIFY_READ, buf, count))
697 		return -EFAULT; /* protects following copy_from_user()s + get_user()s */
698 
699 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
700 	if (!(srp = sg_add_request(sfp))) {
701 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
702 					      "sg_new_write: queue full\n"));
703 		return -EDOM;
704 	}
705 	srp->sg_io_owned = sg_io_owned;
706 	hp = &srp->header;
707 	if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
708 		sg_remove_request(sfp, srp);
709 		return -EFAULT;
710 	}
711 	if (hp->interface_id != 'S') {
712 		sg_remove_request(sfp, srp);
713 		return -ENOSYS;
714 	}
715 	if (hp->flags & SG_FLAG_MMAP_IO) {
716 		if (hp->dxfer_len > sfp->reserve.bufflen) {
717 			sg_remove_request(sfp, srp);
718 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
719 		}
720 		if (hp->flags & SG_FLAG_DIRECT_IO) {
721 			sg_remove_request(sfp, srp);
722 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
723 		}
724 		if (sg_res_in_use(sfp)) {
725 			sg_remove_request(sfp, srp);
726 			return -EBUSY;	/* reserve buffer already being used */
727 		}
728 	}
729 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
730 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
731 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
732 		sg_remove_request(sfp, srp);
733 		return -EMSGSIZE;
734 	}
735 	if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
736 		sg_remove_request(sfp, srp);
737 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
738 	}
739 	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
740 		sg_remove_request(sfp, srp);
741 		return -EFAULT;
742 	}
743 	if (read_only && sg_allow_access(file, cmnd)) {
744 		sg_remove_request(sfp, srp);
745 		return -EPERM;
746 	}
747 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
748 	if (k < 0)
749 		return k;
750 	if (o_srp)
751 		*o_srp = srp;
752 	return count;
753 }
754 
755 static int
756 sg_common_write(Sg_fd * sfp, Sg_request * srp,
757 		unsigned char *cmnd, int timeout, int blocking)
758 {
759 	int k, at_head;
760 	Sg_device *sdp = sfp->parentdp;
761 	sg_io_hdr_t *hp = &srp->header;
762 
763 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
764 	hp->status = 0;
765 	hp->masked_status = 0;
766 	hp->msg_status = 0;
767 	hp->info = 0;
768 	hp->host_status = 0;
769 	hp->driver_status = 0;
770 	hp->resid = 0;
771 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
772 			"sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
773 			(int) cmnd[0], (int) hp->cmd_len));
774 
775 	k = sg_start_req(srp, cmnd);
776 	if (k) {
777 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
778 			"sg_common_write: start_req err=%d\n", k));
779 		sg_finish_rem_req(srp);
780 		return k;	/* probably out of space --> ENOMEM */
781 	}
782 	if (atomic_read(&sdp->detaching)) {
783 		if (srp->bio) {
784 			scsi_req_free_cmd(scsi_req(srp->rq));
785 			blk_end_request_all(srp->rq, -EIO);
786 			srp->rq = NULL;
787 		}
788 
789 		sg_finish_rem_req(srp);
790 		return -ENODEV;
791 	}
792 
793 	hp->duration = jiffies_to_msecs(jiffies);
794 	if (hp->interface_id != '\0' &&	/* v3 (or later) interface */
795 	    (SG_FLAG_Q_AT_TAIL & hp->flags))
796 		at_head = 0;
797 	else
798 		at_head = 1;
799 
800 	srp->rq->timeout = timeout;
801 	kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
802 	blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
803 			      srp->rq, at_head, sg_rq_end_io);
804 	return 0;
805 }
806 
807 static int srp_done(Sg_fd *sfp, Sg_request *srp)
808 {
809 	unsigned long flags;
810 	int ret;
811 
812 	read_lock_irqsave(&sfp->rq_list_lock, flags);
813 	ret = srp->done;
814 	read_unlock_irqrestore(&sfp->rq_list_lock, flags);
815 	return ret;
816 }
817 
818 static int max_sectors_bytes(struct request_queue *q)
819 {
820 	unsigned int max_sectors = queue_max_sectors(q);
821 
822 	max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
823 
824 	return max_sectors << 9;
825 }
826 
827 static long
828 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
829 {
830 	void __user *p = (void __user *)arg;
831 	int __user *ip = p;
832 	int result, val, read_only;
833 	Sg_device *sdp;
834 	Sg_fd *sfp;
835 	Sg_request *srp;
836 	unsigned long iflags;
837 
838 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
839 		return -ENXIO;
840 
841 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
842 				   "sg_ioctl: cmd=0x%x\n", (int) cmd_in));
843 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
844 
845 	switch (cmd_in) {
846 	case SG_IO:
847 		if (atomic_read(&sdp->detaching))
848 			return -ENODEV;
849 		if (!scsi_block_when_processing_errors(sdp->device))
850 			return -ENXIO;
851 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
852 			return -EFAULT;
853 		result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
854 				 1, read_only, 1, &srp);
855 		if (result < 0)
856 			return result;
857 		result = wait_event_interruptible(sfp->read_wait,
858 			(srp_done(sfp, srp) || atomic_read(&sdp->detaching)));
859 		if (atomic_read(&sdp->detaching))
860 			return -ENODEV;
861 		write_lock_irq(&sfp->rq_list_lock);
862 		if (srp->done) {
863 			srp->done = 2;
864 			write_unlock_irq(&sfp->rq_list_lock);
865 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
866 			return (result < 0) ? result : 0;
867 		}
868 		srp->orphan = 1;
869 		write_unlock_irq(&sfp->rq_list_lock);
870 		return result;	/* -ERESTARTSYS because signal hit process */
871 	case SG_SET_TIMEOUT:
872 		result = get_user(val, ip);
873 		if (result)
874 			return result;
875 		if (val < 0)
876 			return -EIO;
877 		if (val >= mult_frac((s64)INT_MAX, USER_HZ, HZ))
878 			val = min_t(s64, mult_frac((s64)INT_MAX, USER_HZ, HZ),
879 				    INT_MAX);
880 		sfp->timeout_user = val;
881 		sfp->timeout = mult_frac(val, HZ, USER_HZ);
882 
883 		return 0;
884 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
885 				/* strange ..., for backward compatibility */
886 		return sfp->timeout_user;
887 	case SG_SET_FORCE_LOW_DMA:
888 		result = get_user(val, ip);
889 		if (result)
890 			return result;
891 		if (val) {
892 			sfp->low_dma = 1;
893 			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
894 				val = (int) sfp->reserve.bufflen;
895 				sg_remove_scat(sfp, &sfp->reserve);
896 				sg_build_reserve(sfp, val);
897 			}
898 		} else {
899 			if (atomic_read(&sdp->detaching))
900 				return -ENODEV;
901 			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
902 		}
903 		return 0;
904 	case SG_GET_LOW_DMA:
905 		return put_user((int) sfp->low_dma, ip);
906 	case SG_GET_SCSI_ID:
907 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
908 			return -EFAULT;
909 		else {
910 			sg_scsi_id_t __user *sg_idp = p;
911 
912 			if (atomic_read(&sdp->detaching))
913 				return -ENODEV;
914 			__put_user((int) sdp->device->host->host_no,
915 				   &sg_idp->host_no);
916 			__put_user((int) sdp->device->channel,
917 				   &sg_idp->channel);
918 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
919 			__put_user((int) sdp->device->lun, &sg_idp->lun);
920 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
921 			__put_user((short) sdp->device->host->cmd_per_lun,
922 				   &sg_idp->h_cmd_per_lun);
923 			__put_user((short) sdp->device->queue_depth,
924 				   &sg_idp->d_queue_depth);
925 			__put_user(0, &sg_idp->unused[0]);
926 			__put_user(0, &sg_idp->unused[1]);
927 			return 0;
928 		}
929 	case SG_SET_FORCE_PACK_ID:
930 		result = get_user(val, ip);
931 		if (result)
932 			return result;
933 		sfp->force_packid = val ? 1 : 0;
934 		return 0;
935 	case SG_GET_PACK_ID:
936 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
937 			return -EFAULT;
938 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
939 		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
940 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
941 				read_unlock_irqrestore(&sfp->rq_list_lock,
942 						       iflags);
943 				__put_user(srp->header.pack_id, ip);
944 				return 0;
945 			}
946 		}
947 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
948 		__put_user(-1, ip);
949 		return 0;
950 	case SG_GET_NUM_WAITING:
951 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
952 		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
953 			if ((1 == srp->done) && (!srp->sg_io_owned))
954 				++val;
955 		}
956 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
957 		return put_user(val, ip);
958 	case SG_GET_SG_TABLESIZE:
959 		return put_user(sdp->sg_tablesize, ip);
960 	case SG_SET_RESERVED_SIZE:
961 		result = get_user(val, ip);
962 		if (result)
963 			return result;
964                 if (val < 0)
965                         return -EINVAL;
966 		val = min_t(int, val,
967 			    max_sectors_bytes(sdp->device->request_queue));
968 		if (val != sfp->reserve.bufflen) {
969 			if (sg_res_in_use(sfp) || sfp->mmap_called)
970 				return -EBUSY;
971 			sg_remove_scat(sfp, &sfp->reserve);
972 			sg_build_reserve(sfp, val);
973 		}
974 		return 0;
975 	case SG_GET_RESERVED_SIZE:
976 		val = min_t(int, sfp->reserve.bufflen,
977 			    max_sectors_bytes(sdp->device->request_queue));
978 		return put_user(val, ip);
979 	case SG_SET_COMMAND_Q:
980 		result = get_user(val, ip);
981 		if (result)
982 			return result;
983 		sfp->cmd_q = val ? 1 : 0;
984 		return 0;
985 	case SG_GET_COMMAND_Q:
986 		return put_user((int) sfp->cmd_q, ip);
987 	case SG_SET_KEEP_ORPHAN:
988 		result = get_user(val, ip);
989 		if (result)
990 			return result;
991 		sfp->keep_orphan = val;
992 		return 0;
993 	case SG_GET_KEEP_ORPHAN:
994 		return put_user((int) sfp->keep_orphan, ip);
995 	case SG_NEXT_CMD_LEN:
996 		result = get_user(val, ip);
997 		if (result)
998 			return result;
999 		sfp->next_cmd_len = (val > 0) ? val : 0;
1000 		return 0;
1001 	case SG_GET_VERSION_NUM:
1002 		return put_user(sg_version_num, ip);
1003 	case SG_GET_ACCESS_COUNT:
1004 		/* faked - we don't have a real access count anymore */
1005 		val = (sdp->device ? 1 : 0);
1006 		return put_user(val, ip);
1007 	case SG_GET_REQUEST_TABLE:
1008 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
1009 			return -EFAULT;
1010 		else {
1011 			sg_req_info_t *rinfo;
1012 			unsigned int ms;
1013 
1014 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
1015 								GFP_KERNEL);
1016 			if (!rinfo)
1017 				return -ENOMEM;
1018 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
1019 			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
1020 			     ++val, srp = srp ? srp->nextrp : srp) {
1021 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
1022 				if (srp) {
1023 					rinfo[val].req_state = srp->done + 1;
1024 					rinfo[val].problem =
1025 					    srp->header.masked_status &
1026 					    srp->header.host_status &
1027 					    srp->header.driver_status;
1028 					if (srp->done)
1029 						rinfo[val].duration =
1030 							srp->header.duration;
1031 					else {
1032 						ms = jiffies_to_msecs(jiffies);
1033 						rinfo[val].duration =
1034 						    (ms > srp->header.duration) ?
1035 						    (ms - srp->header.duration) : 0;
1036 					}
1037 					rinfo[val].orphan = srp->orphan;
1038 					rinfo[val].sg_io_owned =
1039 							srp->sg_io_owned;
1040 					rinfo[val].pack_id =
1041 							srp->header.pack_id;
1042 					rinfo[val].usr_ptr =
1043 							srp->header.usr_ptr;
1044 				}
1045 			}
1046 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1047 			result = __copy_to_user(p, rinfo,
1048 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1049 			result = result ? -EFAULT : 0;
1050 			kfree(rinfo);
1051 			return result;
1052 		}
1053 	case SG_EMULATED_HOST:
1054 		if (atomic_read(&sdp->detaching))
1055 			return -ENODEV;
1056 		return put_user(sdp->device->host->hostt->emulated, ip);
1057 	case SCSI_IOCTL_SEND_COMMAND:
1058 		if (atomic_read(&sdp->detaching))
1059 			return -ENODEV;
1060 		if (read_only) {
1061 			unsigned char opcode = WRITE_6;
1062 			Scsi_Ioctl_Command __user *siocp = p;
1063 
1064 			if (copy_from_user(&opcode, siocp->data, 1))
1065 				return -EFAULT;
1066 			if (sg_allow_access(filp, &opcode))
1067 				return -EPERM;
1068 		}
1069 		return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1070 	case SG_SET_DEBUG:
1071 		result = get_user(val, ip);
1072 		if (result)
1073 			return result;
1074 		sdp->sgdebug = (char) val;
1075 		return 0;
1076 	case BLKSECTGET:
1077 		return put_user(max_sectors_bytes(sdp->device->request_queue),
1078 				ip);
1079 	case BLKTRACESETUP:
1080 		return blk_trace_setup(sdp->device->request_queue,
1081 				       sdp->disk->disk_name,
1082 				       MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1083 				       NULL,
1084 				       (char *)arg);
1085 	case BLKTRACESTART:
1086 		return blk_trace_startstop(sdp->device->request_queue, 1);
1087 	case BLKTRACESTOP:
1088 		return blk_trace_startstop(sdp->device->request_queue, 0);
1089 	case BLKTRACETEARDOWN:
1090 		return blk_trace_remove(sdp->device->request_queue);
1091 	case SCSI_IOCTL_GET_IDLUN:
1092 	case SCSI_IOCTL_GET_BUS_NUMBER:
1093 	case SCSI_IOCTL_PROBE_HOST:
1094 	case SG_GET_TRANSFORM:
1095 	case SG_SCSI_RESET:
1096 		if (atomic_read(&sdp->detaching))
1097 			return -ENODEV;
1098 		break;
1099 	default:
1100 		if (read_only)
1101 			return -EPERM;	/* don't know so take safe approach */
1102 		break;
1103 	}
1104 
1105 	result = scsi_ioctl_block_when_processing_errors(sdp->device,
1106 			cmd_in, filp->f_flags & O_NDELAY);
1107 	if (result)
1108 		return result;
1109 	return scsi_ioctl(sdp->device, cmd_in, p);
1110 }
1111 
1112 #ifdef CONFIG_COMPAT
1113 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1114 {
1115 	Sg_device *sdp;
1116 	Sg_fd *sfp;
1117 	struct scsi_device *sdev;
1118 
1119 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1120 		return -ENXIO;
1121 
1122 	sdev = sdp->device;
1123 	if (sdev->host->hostt->compat_ioctl) {
1124 		int ret;
1125 
1126 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1127 
1128 		return ret;
1129 	}
1130 
1131 	return -ENOIOCTLCMD;
1132 }
1133 #endif
1134 
1135 static unsigned int
1136 sg_poll(struct file *filp, poll_table * wait)
1137 {
1138 	unsigned int res = 0;
1139 	Sg_device *sdp;
1140 	Sg_fd *sfp;
1141 	Sg_request *srp;
1142 	int count = 0;
1143 	unsigned long iflags;
1144 
1145 	sfp = filp->private_data;
1146 	if (!sfp)
1147 		return POLLERR;
1148 	sdp = sfp->parentdp;
1149 	if (!sdp)
1150 		return POLLERR;
1151 	poll_wait(filp, &sfp->read_wait, wait);
1152 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1153 	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1154 		/* if any read waiting, flag it */
1155 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1156 			res = POLLIN | POLLRDNORM;
1157 		++count;
1158 	}
1159 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1160 
1161 	if (atomic_read(&sdp->detaching))
1162 		res |= POLLHUP;
1163 	else if (!sfp->cmd_q) {
1164 		if (0 == count)
1165 			res |= POLLOUT | POLLWRNORM;
1166 	} else if (count < SG_MAX_QUEUE)
1167 		res |= POLLOUT | POLLWRNORM;
1168 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1169 				      "sg_poll: res=0x%x\n", (int) res));
1170 	return res;
1171 }
1172 
1173 static int
1174 sg_fasync(int fd, struct file *filp, int mode)
1175 {
1176 	Sg_device *sdp;
1177 	Sg_fd *sfp;
1178 
1179 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1180 		return -ENXIO;
1181 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1182 				      "sg_fasync: mode=%d\n", mode));
1183 
1184 	return fasync_helper(fd, filp, mode, &sfp->async_qp);
1185 }
1186 
1187 static int
1188 sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1189 {
1190 	Sg_fd *sfp;
1191 	unsigned long offset, len, sa;
1192 	Sg_scatter_hold *rsv_schp;
1193 	int k, length;
1194 
1195 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1196 		return VM_FAULT_SIGBUS;
1197 	rsv_schp = &sfp->reserve;
1198 	offset = vmf->pgoff << PAGE_SHIFT;
1199 	if (offset >= rsv_schp->bufflen)
1200 		return VM_FAULT_SIGBUS;
1201 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1202 				      "sg_vma_fault: offset=%lu, scatg=%d\n",
1203 				      offset, rsv_schp->k_use_sg));
1204 	sa = vma->vm_start;
1205 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1206 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1207 		len = vma->vm_end - sa;
1208 		len = (len < length) ? len : length;
1209 		if (offset < len) {
1210 			struct page *page = nth_page(rsv_schp->pages[k],
1211 						     offset >> PAGE_SHIFT);
1212 			get_page(page);	/* increment page count */
1213 			vmf->page = page;
1214 			return 0; /* success */
1215 		}
1216 		sa += len;
1217 		offset -= len;
1218 	}
1219 
1220 	return VM_FAULT_SIGBUS;
1221 }
1222 
1223 static const struct vm_operations_struct sg_mmap_vm_ops = {
1224 	.fault = sg_vma_fault,
1225 };
1226 
1227 static int
1228 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1229 {
1230 	Sg_fd *sfp;
1231 	unsigned long req_sz, len, sa;
1232 	Sg_scatter_hold *rsv_schp;
1233 	int k, length;
1234 
1235 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1236 		return -ENXIO;
1237 	req_sz = vma->vm_end - vma->vm_start;
1238 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1239 				      "sg_mmap starting, vm_start=%p, len=%d\n",
1240 				      (void *) vma->vm_start, (int) req_sz));
1241 	if (vma->vm_pgoff)
1242 		return -EINVAL;	/* want no offset */
1243 	rsv_schp = &sfp->reserve;
1244 	if (req_sz > rsv_schp->bufflen)
1245 		return -ENOMEM;	/* cannot map more than reserved buffer */
1246 
1247 	sa = vma->vm_start;
1248 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1249 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1250 		len = vma->vm_end - sa;
1251 		len = (len < length) ? len : length;
1252 		sa += len;
1253 	}
1254 
1255 	sfp->mmap_called = 1;
1256 	vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
1257 	vma->vm_private_data = sfp;
1258 	vma->vm_ops = &sg_mmap_vm_ops;
1259 	return 0;
1260 }
1261 
1262 static void
1263 sg_rq_end_io_usercontext(struct work_struct *work)
1264 {
1265 	struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1266 	struct sg_fd *sfp = srp->parentfp;
1267 
1268 	sg_finish_rem_req(srp);
1269 	kref_put(&sfp->f_ref, sg_remove_sfp);
1270 }
1271 
1272 /*
1273  * This function is a "bottom half" handler that is called by the mid
1274  * level when a command is completed (or has failed).
1275  */
1276 static void
1277 sg_rq_end_io(struct request *rq, int uptodate)
1278 {
1279 	struct sg_request *srp = rq->end_io_data;
1280 	struct scsi_request *req = scsi_req(rq);
1281 	Sg_device *sdp;
1282 	Sg_fd *sfp;
1283 	unsigned long iflags;
1284 	unsigned int ms;
1285 	char *sense;
1286 	int result, resid, done = 1;
1287 
1288 	if (WARN_ON(srp->done != 0))
1289 		return;
1290 
1291 	sfp = srp->parentfp;
1292 	if (WARN_ON(sfp == NULL))
1293 		return;
1294 
1295 	sdp = sfp->parentdp;
1296 	if (unlikely(atomic_read(&sdp->detaching)))
1297 		pr_info("%s: device detaching\n", __func__);
1298 
1299 	sense = req->sense;
1300 	result = rq->errors;
1301 	resid = req->resid_len;
1302 
1303 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
1304 				      "sg_cmd_done: pack_id=%d, res=0x%x\n",
1305 				      srp->header.pack_id, result));
1306 	srp->header.resid = resid;
1307 	ms = jiffies_to_msecs(jiffies);
1308 	srp->header.duration = (ms > srp->header.duration) ?
1309 				(ms - srp->header.duration) : 0;
1310 	if (0 != result) {
1311 		struct scsi_sense_hdr sshdr;
1312 
1313 		srp->header.status = 0xff & result;
1314 		srp->header.masked_status = status_byte(result);
1315 		srp->header.msg_status = msg_byte(result);
1316 		srp->header.host_status = host_byte(result);
1317 		srp->header.driver_status = driver_byte(result);
1318 		if ((sdp->sgdebug > 0) &&
1319 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1320 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1321 			__scsi_print_sense(sdp->device, __func__, sense,
1322 					   SCSI_SENSE_BUFFERSIZE);
1323 
1324 		/* Following if statement is a patch supplied by Eric Youngdale */
1325 		if (driver_byte(result) != 0
1326 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1327 		    && !scsi_sense_is_deferred(&sshdr)
1328 		    && sshdr.sense_key == UNIT_ATTENTION
1329 		    && sdp->device->removable) {
1330 			/* Detected possible disc change. Set the bit - this */
1331 			/* may be used if there are filesystems using this device */
1332 			sdp->device->changed = 1;
1333 		}
1334 	}
1335 
1336 	if (req->sense_len)
1337 		memcpy(srp->sense_b, req->sense, SCSI_SENSE_BUFFERSIZE);
1338 
1339 	/* Rely on write phase to clean out srp status values, so no "else" */
1340 
1341 	/*
1342 	 * Free the request as soon as it is complete so that its resources
1343 	 * can be reused without waiting for userspace to read() the
1344 	 * result.  But keep the associated bio (if any) around until
1345 	 * blk_rq_unmap_user() can be called from user context.
1346 	 */
1347 	srp->rq = NULL;
1348 	scsi_req_free_cmd(scsi_req(rq));
1349 	__blk_put_request(rq->q, rq);
1350 
1351 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1352 	if (unlikely(srp->orphan)) {
1353 		if (sfp->keep_orphan)
1354 			srp->sg_io_owned = 0;
1355 		else
1356 			done = 0;
1357 	}
1358 	srp->done = done;
1359 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1360 
1361 	if (likely(done)) {
1362 		/* Now wake up any sg_read() that is waiting for this
1363 		 * packet.
1364 		 */
1365 		wake_up_interruptible(&sfp->read_wait);
1366 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1367 		kref_put(&sfp->f_ref, sg_remove_sfp);
1368 	} else {
1369 		INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1370 		schedule_work(&srp->ew.work);
1371 	}
1372 }
1373 
1374 static const struct file_operations sg_fops = {
1375 	.owner = THIS_MODULE,
1376 	.read = sg_read,
1377 	.write = sg_write,
1378 	.poll = sg_poll,
1379 	.unlocked_ioctl = sg_ioctl,
1380 #ifdef CONFIG_COMPAT
1381 	.compat_ioctl = sg_compat_ioctl,
1382 #endif
1383 	.open = sg_open,
1384 	.mmap = sg_mmap,
1385 	.release = sg_release,
1386 	.fasync = sg_fasync,
1387 	.llseek = no_llseek,
1388 };
1389 
1390 static struct class *sg_sysfs_class;
1391 
1392 static int sg_sysfs_valid = 0;
1393 
1394 static Sg_device *
1395 sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1396 {
1397 	struct request_queue *q = scsidp->request_queue;
1398 	Sg_device *sdp;
1399 	unsigned long iflags;
1400 	int error;
1401 	u32 k;
1402 
1403 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1404 	if (!sdp) {
1405 		sdev_printk(KERN_WARNING, scsidp, "%s: kmalloc Sg_device "
1406 			    "failure\n", __func__);
1407 		return ERR_PTR(-ENOMEM);
1408 	}
1409 
1410 	idr_preload(GFP_KERNEL);
1411 	write_lock_irqsave(&sg_index_lock, iflags);
1412 
1413 	error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
1414 	if (error < 0) {
1415 		if (error == -ENOSPC) {
1416 			sdev_printk(KERN_WARNING, scsidp,
1417 				    "Unable to attach sg device type=%d, minor number exceeds %d\n",
1418 				    scsidp->type, SG_MAX_DEVS - 1);
1419 			error = -ENODEV;
1420 		} else {
1421 			sdev_printk(KERN_WARNING, scsidp, "%s: idr "
1422 				    "allocation Sg_device failure: %d\n",
1423 				    __func__, error);
1424 		}
1425 		goto out_unlock;
1426 	}
1427 	k = error;
1428 
1429 	SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, scsidp,
1430 					"sg_alloc: dev=%d \n", k));
1431 	sprintf(disk->disk_name, "sg%d", k);
1432 	disk->first_minor = k;
1433 	sdp->disk = disk;
1434 	sdp->device = scsidp;
1435 	mutex_init(&sdp->open_rel_lock);
1436 	INIT_LIST_HEAD(&sdp->sfds);
1437 	init_waitqueue_head(&sdp->open_wait);
1438 	atomic_set(&sdp->detaching, 0);
1439 	rwlock_init(&sdp->sfd_lock);
1440 	sdp->sg_tablesize = queue_max_segments(q);
1441 	sdp->index = k;
1442 	kref_init(&sdp->d_ref);
1443 	error = 0;
1444 
1445 out_unlock:
1446 	write_unlock_irqrestore(&sg_index_lock, iflags);
1447 	idr_preload_end();
1448 
1449 	if (error) {
1450 		kfree(sdp);
1451 		return ERR_PTR(error);
1452 	}
1453 	return sdp;
1454 }
1455 
1456 static int
1457 sg_add_device(struct device *cl_dev, struct class_interface *cl_intf)
1458 {
1459 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1460 	struct gendisk *disk;
1461 	Sg_device *sdp = NULL;
1462 	struct cdev * cdev = NULL;
1463 	int error;
1464 	unsigned long iflags;
1465 
1466 	disk = alloc_disk(1);
1467 	if (!disk) {
1468 		pr_warn("%s: alloc_disk failed\n", __func__);
1469 		return -ENOMEM;
1470 	}
1471 	disk->major = SCSI_GENERIC_MAJOR;
1472 
1473 	error = -ENOMEM;
1474 	cdev = cdev_alloc();
1475 	if (!cdev) {
1476 		pr_warn("%s: cdev_alloc failed\n", __func__);
1477 		goto out;
1478 	}
1479 	cdev->owner = THIS_MODULE;
1480 	cdev->ops = &sg_fops;
1481 
1482 	sdp = sg_alloc(disk, scsidp);
1483 	if (IS_ERR(sdp)) {
1484 		pr_warn("%s: sg_alloc failed\n", __func__);
1485 		error = PTR_ERR(sdp);
1486 		goto out;
1487 	}
1488 
1489 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1490 	if (error)
1491 		goto cdev_add_err;
1492 
1493 	sdp->cdev = cdev;
1494 	if (sg_sysfs_valid) {
1495 		struct device *sg_class_member;
1496 
1497 		sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1498 						MKDEV(SCSI_GENERIC_MAJOR,
1499 						      sdp->index),
1500 						sdp, "%s", disk->disk_name);
1501 		if (IS_ERR(sg_class_member)) {
1502 			pr_err("%s: device_create failed\n", __func__);
1503 			error = PTR_ERR(sg_class_member);
1504 			goto cdev_add_err;
1505 		}
1506 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1507 					  &sg_class_member->kobj, "generic");
1508 		if (error)
1509 			pr_err("%s: unable to make symlink 'generic' back "
1510 			       "to sg%d\n", __func__, sdp->index);
1511 	} else
1512 		pr_warn("%s: sg_sys Invalid\n", __func__);
1513 
1514 	sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d "
1515 		    "type %d\n", sdp->index, scsidp->type);
1516 
1517 	dev_set_drvdata(cl_dev, sdp);
1518 
1519 	return 0;
1520 
1521 cdev_add_err:
1522 	write_lock_irqsave(&sg_index_lock, iflags);
1523 	idr_remove(&sg_index_idr, sdp->index);
1524 	write_unlock_irqrestore(&sg_index_lock, iflags);
1525 	kfree(sdp);
1526 
1527 out:
1528 	put_disk(disk);
1529 	if (cdev)
1530 		cdev_del(cdev);
1531 	return error;
1532 }
1533 
1534 static void
1535 sg_device_destroy(struct kref *kref)
1536 {
1537 	struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1538 	unsigned long flags;
1539 
1540 	/* CAUTION!  Note that the device can still be found via idr_find()
1541 	 * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1542 	 * any other cleanup.
1543 	 */
1544 
1545 	write_lock_irqsave(&sg_index_lock, flags);
1546 	idr_remove(&sg_index_idr, sdp->index);
1547 	write_unlock_irqrestore(&sg_index_lock, flags);
1548 
1549 	SCSI_LOG_TIMEOUT(3,
1550 		sg_printk(KERN_INFO, sdp, "sg_device_destroy\n"));
1551 
1552 	put_disk(sdp->disk);
1553 	kfree(sdp);
1554 }
1555 
1556 static void
1557 sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf)
1558 {
1559 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1560 	Sg_device *sdp = dev_get_drvdata(cl_dev);
1561 	unsigned long iflags;
1562 	Sg_fd *sfp;
1563 	int val;
1564 
1565 	if (!sdp)
1566 		return;
1567 	/* want sdp->detaching non-zero as soon as possible */
1568 	val = atomic_inc_return(&sdp->detaching);
1569 	if (val > 1)
1570 		return; /* only want to do following once per device */
1571 
1572 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1573 				      "%s\n", __func__));
1574 
1575 	read_lock_irqsave(&sdp->sfd_lock, iflags);
1576 	list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1577 		wake_up_interruptible_all(&sfp->read_wait);
1578 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1579 	}
1580 	wake_up_interruptible_all(&sdp->open_wait);
1581 	read_unlock_irqrestore(&sdp->sfd_lock, iflags);
1582 
1583 	sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1584 	device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1585 	cdev_del(sdp->cdev);
1586 	sdp->cdev = NULL;
1587 
1588 	kref_put(&sdp->d_ref, sg_device_destroy);
1589 }
1590 
1591 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1592 module_param_named(def_reserved_size, def_reserved_size, int,
1593 		   S_IRUGO | S_IWUSR);
1594 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1595 
1596 MODULE_AUTHOR("Douglas Gilbert");
1597 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1598 MODULE_LICENSE("GPL");
1599 MODULE_VERSION(SG_VERSION_STR);
1600 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1601 
1602 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1603                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1604 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1605 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1606 
1607 static int __init
1608 init_sg(void)
1609 {
1610 	int rc;
1611 
1612 	if (scatter_elem_sz < PAGE_SIZE) {
1613 		scatter_elem_sz = PAGE_SIZE;
1614 		scatter_elem_sz_prev = scatter_elem_sz;
1615 	}
1616 	if (def_reserved_size >= 0)
1617 		sg_big_buff = def_reserved_size;
1618 	else
1619 		def_reserved_size = sg_big_buff;
1620 
1621 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1622 				    SG_MAX_DEVS, "sg");
1623 	if (rc)
1624 		return rc;
1625         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1626         if ( IS_ERR(sg_sysfs_class) ) {
1627 		rc = PTR_ERR(sg_sysfs_class);
1628 		goto err_out;
1629         }
1630 	sg_sysfs_valid = 1;
1631 	rc = scsi_register_interface(&sg_interface);
1632 	if (0 == rc) {
1633 #ifdef CONFIG_SCSI_PROC_FS
1634 		sg_proc_init();
1635 #endif				/* CONFIG_SCSI_PROC_FS */
1636 		return 0;
1637 	}
1638 	class_destroy(sg_sysfs_class);
1639 err_out:
1640 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1641 	return rc;
1642 }
1643 
1644 static void __exit
1645 exit_sg(void)
1646 {
1647 #ifdef CONFIG_SCSI_PROC_FS
1648 	sg_proc_cleanup();
1649 #endif				/* CONFIG_SCSI_PROC_FS */
1650 	scsi_unregister_interface(&sg_interface);
1651 	class_destroy(sg_sysfs_class);
1652 	sg_sysfs_valid = 0;
1653 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1654 				 SG_MAX_DEVS);
1655 	idr_destroy(&sg_index_idr);
1656 }
1657 
1658 static int
1659 sg_start_req(Sg_request *srp, unsigned char *cmd)
1660 {
1661 	int res;
1662 	struct request *rq;
1663 	struct scsi_request *req;
1664 	Sg_fd *sfp = srp->parentfp;
1665 	sg_io_hdr_t *hp = &srp->header;
1666 	int dxfer_len = (int) hp->dxfer_len;
1667 	int dxfer_dir = hp->dxfer_direction;
1668 	unsigned int iov_count = hp->iovec_count;
1669 	Sg_scatter_hold *req_schp = &srp->data;
1670 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1671 	struct request_queue *q = sfp->parentdp->device->request_queue;
1672 	struct rq_map_data *md, map_data;
1673 	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1674 	unsigned char *long_cmdp = NULL;
1675 
1676 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1677 				      "sg_start_req: dxfer_len=%d\n",
1678 				      dxfer_len));
1679 
1680 	if (hp->cmd_len > BLK_MAX_CDB) {
1681 		long_cmdp = kzalloc(hp->cmd_len, GFP_KERNEL);
1682 		if (!long_cmdp)
1683 			return -ENOMEM;
1684 	}
1685 
1686 	/*
1687 	 * NOTE
1688 	 *
1689 	 * With scsi-mq enabled, there are a fixed number of preallocated
1690 	 * requests equal in number to shost->can_queue.  If all of the
1691 	 * preallocated requests are already in use, then using GFP_ATOMIC with
1692 	 * blk_get_request() will return -EWOULDBLOCK, whereas using GFP_KERNEL
1693 	 * will cause blk_get_request() to sleep until an active command
1694 	 * completes, freeing up a request.  Neither option is ideal, but
1695 	 * GFP_KERNEL is the better choice to prevent userspace from getting an
1696 	 * unexpected EWOULDBLOCK.
1697 	 *
1698 	 * With scsi-mq disabled, blk_get_request() with GFP_KERNEL usually
1699 	 * does not sleep except under memory pressure.
1700 	 */
1701 	rq = blk_get_request(q, hp->dxfer_direction == SG_DXFER_TO_DEV ?
1702 			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, GFP_KERNEL);
1703 	if (IS_ERR(rq)) {
1704 		kfree(long_cmdp);
1705 		return PTR_ERR(rq);
1706 	}
1707 	req = scsi_req(rq);
1708 
1709 	scsi_req_init(rq);
1710 
1711 	if (hp->cmd_len > BLK_MAX_CDB)
1712 		req->cmd = long_cmdp;
1713 	memcpy(req->cmd, cmd, hp->cmd_len);
1714 	req->cmd_len = hp->cmd_len;
1715 
1716 	srp->rq = rq;
1717 	rq->end_io_data = srp;
1718 	rq->retries = SG_DEFAULT_RETRIES;
1719 
1720 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1721 		return 0;
1722 
1723 	if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1724 	    dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1725 	    !sfp->parentdp->device->host->unchecked_isa_dma &&
1726 	    blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1727 		md = NULL;
1728 	else
1729 		md = &map_data;
1730 
1731 	if (md) {
1732 		if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
1733 			sg_link_reserve(sfp, srp, dxfer_len);
1734 		else {
1735 			res = sg_build_indirect(req_schp, sfp, dxfer_len);
1736 			if (res)
1737 				return res;
1738 		}
1739 
1740 		md->pages = req_schp->pages;
1741 		md->page_order = req_schp->page_order;
1742 		md->nr_entries = req_schp->k_use_sg;
1743 		md->offset = 0;
1744 		md->null_mapped = hp->dxferp ? 0 : 1;
1745 		if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1746 			md->from_user = 1;
1747 		else
1748 			md->from_user = 0;
1749 	}
1750 
1751 	if (iov_count) {
1752 		struct iovec *iov = NULL;
1753 		struct iov_iter i;
1754 
1755 		res = import_iovec(rw, hp->dxferp, iov_count, 0, &iov, &i);
1756 		if (res < 0)
1757 			return res;
1758 
1759 		iov_iter_truncate(&i, hp->dxfer_len);
1760 		if (!iov_iter_count(&i)) {
1761 			kfree(iov);
1762 			return -EINVAL;
1763 		}
1764 
1765 		res = blk_rq_map_user_iov(q, rq, md, &i, GFP_ATOMIC);
1766 		kfree(iov);
1767 	} else
1768 		res = blk_rq_map_user(q, rq, md, hp->dxferp,
1769 				      hp->dxfer_len, GFP_ATOMIC);
1770 
1771 	if (!res) {
1772 		srp->bio = rq->bio;
1773 
1774 		if (!md) {
1775 			req_schp->dio_in_use = 1;
1776 			hp->info |= SG_INFO_DIRECT_IO;
1777 		}
1778 	}
1779 	return res;
1780 }
1781 
1782 static int
1783 sg_finish_rem_req(Sg_request *srp)
1784 {
1785 	int ret = 0;
1786 
1787 	Sg_fd *sfp = srp->parentfp;
1788 	Sg_scatter_hold *req_schp = &srp->data;
1789 
1790 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1791 				      "sg_finish_rem_req: res_used=%d\n",
1792 				      (int) srp->res_used));
1793 	if (srp->bio)
1794 		ret = blk_rq_unmap_user(srp->bio);
1795 
1796 	if (srp->rq) {
1797 		scsi_req_free_cmd(scsi_req(srp->rq));
1798 		blk_put_request(srp->rq);
1799 	}
1800 
1801 	if (srp->res_used)
1802 		sg_unlink_reserve(sfp, srp);
1803 	else
1804 		sg_remove_scat(sfp, req_schp);
1805 
1806 	sg_remove_request(sfp, srp);
1807 
1808 	return ret;
1809 }
1810 
1811 static int
1812 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1813 {
1814 	int sg_bufflen = tablesize * sizeof(struct page *);
1815 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1816 
1817 	schp->pages = kzalloc(sg_bufflen, gfp_flags);
1818 	if (!schp->pages)
1819 		return -ENOMEM;
1820 	schp->sglist_len = sg_bufflen;
1821 	return tablesize;	/* number of scat_gath elements allocated */
1822 }
1823 
1824 static int
1825 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1826 {
1827 	int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1828 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1829 	int blk_size = buff_size, order;
1830 	gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
1831 
1832 	if (blk_size < 0)
1833 		return -EFAULT;
1834 	if (0 == blk_size)
1835 		++blk_size;	/* don't know why */
1836 	/* round request up to next highest SG_SECTOR_SZ byte boundary */
1837 	blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1838 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1839 		"sg_build_indirect: buff_size=%d, blk_size=%d\n",
1840 		buff_size, blk_size));
1841 
1842 	/* N.B. ret_sz carried into this block ... */
1843 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1844 	if (mx_sc_elems < 0)
1845 		return mx_sc_elems;	/* most likely -ENOMEM */
1846 
1847 	num = scatter_elem_sz;
1848 	if (unlikely(num != scatter_elem_sz_prev)) {
1849 		if (num < PAGE_SIZE) {
1850 			scatter_elem_sz = PAGE_SIZE;
1851 			scatter_elem_sz_prev = PAGE_SIZE;
1852 		} else
1853 			scatter_elem_sz_prev = num;
1854 	}
1855 
1856 	if (sfp->low_dma)
1857 		gfp_mask |= GFP_DMA;
1858 
1859 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1860 		gfp_mask |= __GFP_ZERO;
1861 
1862 	order = get_order(num);
1863 retry:
1864 	ret_sz = 1 << (PAGE_SHIFT + order);
1865 
1866 	for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1867 	     k++, rem_sz -= ret_sz) {
1868 
1869 		num = (rem_sz > scatter_elem_sz_prev) ?
1870 			scatter_elem_sz_prev : rem_sz;
1871 
1872 		schp->pages[k] = alloc_pages(gfp_mask, order);
1873 		if (!schp->pages[k])
1874 			goto out;
1875 
1876 		if (num == scatter_elem_sz_prev) {
1877 			if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1878 				scatter_elem_sz = ret_sz;
1879 				scatter_elem_sz_prev = ret_sz;
1880 			}
1881 		}
1882 
1883 		SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1884 				 "sg_build_indirect: k=%d, num=%d, ret_sz=%d\n",
1885 				 k, num, ret_sz));
1886 	}		/* end of for loop */
1887 
1888 	schp->page_order = order;
1889 	schp->k_use_sg = k;
1890 	SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1891 			 "sg_build_indirect: k_use_sg=%d, rem_sz=%d\n",
1892 			 k, rem_sz));
1893 
1894 	schp->bufflen = blk_size;
1895 	if (rem_sz > 0)	/* must have failed */
1896 		return -ENOMEM;
1897 	return 0;
1898 out:
1899 	for (i = 0; i < k; i++)
1900 		__free_pages(schp->pages[i], order);
1901 
1902 	if (--order >= 0)
1903 		goto retry;
1904 
1905 	return -ENOMEM;
1906 }
1907 
1908 static void
1909 sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp)
1910 {
1911 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1912 			 "sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1913 	if (schp->pages && schp->sglist_len > 0) {
1914 		if (!schp->dio_in_use) {
1915 			int k;
1916 
1917 			for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1918 				SCSI_LOG_TIMEOUT(5,
1919 					sg_printk(KERN_INFO, sfp->parentdp,
1920 					"sg_remove_scat: k=%d, pg=0x%p\n",
1921 					k, schp->pages[k]));
1922 				__free_pages(schp->pages[k], schp->page_order);
1923 			}
1924 
1925 			kfree(schp->pages);
1926 		}
1927 	}
1928 	memset(schp, 0, sizeof (*schp));
1929 }
1930 
1931 static int
1932 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1933 {
1934 	Sg_scatter_hold *schp = &srp->data;
1935 	int k, num;
1936 
1937 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
1938 			 "sg_read_oxfer: num_read_xfer=%d\n",
1939 			 num_read_xfer));
1940 	if ((!outp) || (num_read_xfer <= 0))
1941 		return 0;
1942 
1943 	num = 1 << (PAGE_SHIFT + schp->page_order);
1944 	for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1945 		if (num > num_read_xfer) {
1946 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1947 					   num_read_xfer))
1948 				return -EFAULT;
1949 			break;
1950 		} else {
1951 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1952 					   num))
1953 				return -EFAULT;
1954 			num_read_xfer -= num;
1955 			if (num_read_xfer <= 0)
1956 				break;
1957 			outp += num;
1958 		}
1959 	}
1960 
1961 	return 0;
1962 }
1963 
1964 static void
1965 sg_build_reserve(Sg_fd * sfp, int req_size)
1966 {
1967 	Sg_scatter_hold *schp = &sfp->reserve;
1968 
1969 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1970 			 "sg_build_reserve: req_size=%d\n", req_size));
1971 	do {
1972 		if (req_size < PAGE_SIZE)
1973 			req_size = PAGE_SIZE;
1974 		if (0 == sg_build_indirect(schp, sfp, req_size))
1975 			return;
1976 		else
1977 			sg_remove_scat(sfp, schp);
1978 		req_size >>= 1;	/* divide by 2 */
1979 	} while (req_size > (PAGE_SIZE / 2));
1980 }
1981 
1982 static void
1983 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
1984 {
1985 	Sg_scatter_hold *req_schp = &srp->data;
1986 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1987 	int k, num, rem;
1988 
1989 	srp->res_used = 1;
1990 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1991 			 "sg_link_reserve: size=%d\n", size));
1992 	rem = size;
1993 
1994 	num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1995 	for (k = 0; k < rsv_schp->k_use_sg; k++) {
1996 		if (rem <= num) {
1997 			req_schp->k_use_sg = k + 1;
1998 			req_schp->sglist_len = rsv_schp->sglist_len;
1999 			req_schp->pages = rsv_schp->pages;
2000 
2001 			req_schp->bufflen = size;
2002 			req_schp->page_order = rsv_schp->page_order;
2003 			break;
2004 		} else
2005 			rem -= num;
2006 	}
2007 
2008 	if (k >= rsv_schp->k_use_sg)
2009 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
2010 				 "sg_link_reserve: BAD size\n"));
2011 }
2012 
2013 static void
2014 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2015 {
2016 	Sg_scatter_hold *req_schp = &srp->data;
2017 
2018 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
2019 				      "sg_unlink_reserve: req->k_use_sg=%d\n",
2020 				      (int) req_schp->k_use_sg));
2021 	req_schp->k_use_sg = 0;
2022 	req_schp->bufflen = 0;
2023 	req_schp->pages = NULL;
2024 	req_schp->page_order = 0;
2025 	req_schp->sglist_len = 0;
2026 	sfp->save_scat_len = 0;
2027 	srp->res_used = 0;
2028 }
2029 
2030 static Sg_request *
2031 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2032 {
2033 	Sg_request *resp;
2034 	unsigned long iflags;
2035 
2036 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2037 	for (resp = sfp->headrp; resp; resp = resp->nextrp) {
2038 		/* look for requests that are ready + not SG_IO owned */
2039 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
2040 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2041 			resp->done = 2;	/* guard against other readers */
2042 			break;
2043 		}
2044 	}
2045 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2046 	return resp;
2047 }
2048 
2049 /* always adds to end of list */
2050 static Sg_request *
2051 sg_add_request(Sg_fd * sfp)
2052 {
2053 	int k;
2054 	unsigned long iflags;
2055 	Sg_request *resp;
2056 	Sg_request *rp = sfp->req_arr;
2057 
2058 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2059 	resp = sfp->headrp;
2060 	if (!resp) {
2061 		memset(rp, 0, sizeof (Sg_request));
2062 		rp->parentfp = sfp;
2063 		resp = rp;
2064 		sfp->headrp = resp;
2065 	} else {
2066 		if (0 == sfp->cmd_q)
2067 			resp = NULL;	/* command queuing disallowed */
2068 		else {
2069 			for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2070 				if (!rp->parentfp)
2071 					break;
2072 			}
2073 			if (k < SG_MAX_QUEUE) {
2074 				memset(rp, 0, sizeof (Sg_request));
2075 				rp->parentfp = sfp;
2076 				while (resp->nextrp)
2077 					resp = resp->nextrp;
2078 				resp->nextrp = rp;
2079 				resp = rp;
2080 			} else
2081 				resp = NULL;
2082 		}
2083 	}
2084 	if (resp) {
2085 		resp->nextrp = NULL;
2086 		resp->header.duration = jiffies_to_msecs(jiffies);
2087 	}
2088 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2089 	return resp;
2090 }
2091 
2092 /* Return of 1 for found; 0 for not found */
2093 static int
2094 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2095 {
2096 	Sg_request *prev_rp;
2097 	Sg_request *rp;
2098 	unsigned long iflags;
2099 	int res = 0;
2100 
2101 	if ((!sfp) || (!srp) || (!sfp->headrp))
2102 		return res;
2103 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2104 	prev_rp = sfp->headrp;
2105 	if (srp == prev_rp) {
2106 		sfp->headrp = prev_rp->nextrp;
2107 		prev_rp->parentfp = NULL;
2108 		res = 1;
2109 	} else {
2110 		while ((rp = prev_rp->nextrp)) {
2111 			if (srp == rp) {
2112 				prev_rp->nextrp = rp->nextrp;
2113 				rp->parentfp = NULL;
2114 				res = 1;
2115 				break;
2116 			}
2117 			prev_rp = rp;
2118 		}
2119 	}
2120 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2121 	return res;
2122 }
2123 
2124 static Sg_fd *
2125 sg_add_sfp(Sg_device * sdp)
2126 {
2127 	Sg_fd *sfp;
2128 	unsigned long iflags;
2129 	int bufflen;
2130 
2131 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2132 	if (!sfp)
2133 		return ERR_PTR(-ENOMEM);
2134 
2135 	init_waitqueue_head(&sfp->read_wait);
2136 	rwlock_init(&sfp->rq_list_lock);
2137 
2138 	kref_init(&sfp->f_ref);
2139 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2140 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2141 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2142 	sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2143 	    sdp->device->host->unchecked_isa_dma : 1;
2144 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2145 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2146 	sfp->parentdp = sdp;
2147 	write_lock_irqsave(&sdp->sfd_lock, iflags);
2148 	if (atomic_read(&sdp->detaching)) {
2149 		write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2150 		return ERR_PTR(-ENODEV);
2151 	}
2152 	list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2153 	write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2154 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2155 				      "sg_add_sfp: sfp=0x%p\n", sfp));
2156 	if (unlikely(sg_big_buff != def_reserved_size))
2157 		sg_big_buff = def_reserved_size;
2158 
2159 	bufflen = min_t(int, sg_big_buff,
2160 			max_sectors_bytes(sdp->device->request_queue));
2161 	sg_build_reserve(sfp, bufflen);
2162 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2163 				      "sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
2164 				      sfp->reserve.bufflen,
2165 				      sfp->reserve.k_use_sg));
2166 
2167 	kref_get(&sdp->d_ref);
2168 	__module_get(THIS_MODULE);
2169 	return sfp;
2170 }
2171 
2172 static void
2173 sg_remove_sfp_usercontext(struct work_struct *work)
2174 {
2175 	struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2176 	struct sg_device *sdp = sfp->parentdp;
2177 
2178 	/* Cleanup any responses which were never read(). */
2179 	while (sfp->headrp)
2180 		sg_finish_rem_req(sfp->headrp);
2181 
2182 	if (sfp->reserve.bufflen > 0) {
2183 		SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2184 				"sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2185 				(int) sfp->reserve.bufflen,
2186 				(int) sfp->reserve.k_use_sg));
2187 		sg_remove_scat(sfp, &sfp->reserve);
2188 	}
2189 
2190 	SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2191 			"sg_remove_sfp: sfp=0x%p\n", sfp));
2192 	kfree(sfp);
2193 
2194 	scsi_device_put(sdp->device);
2195 	kref_put(&sdp->d_ref, sg_device_destroy);
2196 	module_put(THIS_MODULE);
2197 }
2198 
2199 static void
2200 sg_remove_sfp(struct kref *kref)
2201 {
2202 	struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2203 	struct sg_device *sdp = sfp->parentdp;
2204 	unsigned long iflags;
2205 
2206 	write_lock_irqsave(&sdp->sfd_lock, iflags);
2207 	list_del(&sfp->sfd_siblings);
2208 	write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2209 
2210 	INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2211 	schedule_work(&sfp->ew.work);
2212 }
2213 
2214 static int
2215 sg_res_in_use(Sg_fd * sfp)
2216 {
2217 	const Sg_request *srp;
2218 	unsigned long iflags;
2219 
2220 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2221 	for (srp = sfp->headrp; srp; srp = srp->nextrp)
2222 		if (srp->res_used)
2223 			break;
2224 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2225 	return srp ? 1 : 0;
2226 }
2227 
2228 #ifdef CONFIG_SCSI_PROC_FS
2229 static int
2230 sg_idr_max_id(int id, void *p, void *data)
2231 {
2232 	int *k = data;
2233 
2234 	if (*k < id)
2235 		*k = id;
2236 
2237 	return 0;
2238 }
2239 
2240 static int
2241 sg_last_dev(void)
2242 {
2243 	int k = -1;
2244 	unsigned long iflags;
2245 
2246 	read_lock_irqsave(&sg_index_lock, iflags);
2247 	idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2248 	read_unlock_irqrestore(&sg_index_lock, iflags);
2249 	return k + 1;		/* origin 1 */
2250 }
2251 #endif
2252 
2253 /* must be called with sg_index_lock held */
2254 static Sg_device *sg_lookup_dev(int dev)
2255 {
2256 	return idr_find(&sg_index_idr, dev);
2257 }
2258 
2259 static Sg_device *
2260 sg_get_dev(int dev)
2261 {
2262 	struct sg_device *sdp;
2263 	unsigned long flags;
2264 
2265 	read_lock_irqsave(&sg_index_lock, flags);
2266 	sdp = sg_lookup_dev(dev);
2267 	if (!sdp)
2268 		sdp = ERR_PTR(-ENXIO);
2269 	else if (atomic_read(&sdp->detaching)) {
2270 		/* If sdp->detaching, then the refcount may already be 0, in
2271 		 * which case it would be a bug to do kref_get().
2272 		 */
2273 		sdp = ERR_PTR(-ENODEV);
2274 	} else
2275 		kref_get(&sdp->d_ref);
2276 	read_unlock_irqrestore(&sg_index_lock, flags);
2277 
2278 	return sdp;
2279 }
2280 
2281 #ifdef CONFIG_SCSI_PROC_FS
2282 
2283 static struct proc_dir_entry *sg_proc_sgp = NULL;
2284 
2285 static char sg_proc_sg_dirname[] = "scsi/sg";
2286 
2287 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2288 
2289 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2290 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2291 			          size_t count, loff_t *off);
2292 static const struct file_operations adio_fops = {
2293 	.owner = THIS_MODULE,
2294 	.open = sg_proc_single_open_adio,
2295 	.read = seq_read,
2296 	.llseek = seq_lseek,
2297 	.write = sg_proc_write_adio,
2298 	.release = single_release,
2299 };
2300 
2301 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2302 static ssize_t sg_proc_write_dressz(struct file *filp,
2303 		const char __user *buffer, size_t count, loff_t *off);
2304 static const struct file_operations dressz_fops = {
2305 	.owner = THIS_MODULE,
2306 	.open = sg_proc_single_open_dressz,
2307 	.read = seq_read,
2308 	.llseek = seq_lseek,
2309 	.write = sg_proc_write_dressz,
2310 	.release = single_release,
2311 };
2312 
2313 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2314 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2315 static const struct file_operations version_fops = {
2316 	.owner = THIS_MODULE,
2317 	.open = sg_proc_single_open_version,
2318 	.read = seq_read,
2319 	.llseek = seq_lseek,
2320 	.release = single_release,
2321 };
2322 
2323 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2324 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2325 static const struct file_operations devhdr_fops = {
2326 	.owner = THIS_MODULE,
2327 	.open = sg_proc_single_open_devhdr,
2328 	.read = seq_read,
2329 	.llseek = seq_lseek,
2330 	.release = single_release,
2331 };
2332 
2333 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2334 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2335 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2336 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2337 static void dev_seq_stop(struct seq_file *s, void *v);
2338 static const struct file_operations dev_fops = {
2339 	.owner = THIS_MODULE,
2340 	.open = sg_proc_open_dev,
2341 	.read = seq_read,
2342 	.llseek = seq_lseek,
2343 	.release = seq_release,
2344 };
2345 static const struct seq_operations dev_seq_ops = {
2346 	.start = dev_seq_start,
2347 	.next  = dev_seq_next,
2348 	.stop  = dev_seq_stop,
2349 	.show  = sg_proc_seq_show_dev,
2350 };
2351 
2352 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2353 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2354 static const struct file_operations devstrs_fops = {
2355 	.owner = THIS_MODULE,
2356 	.open = sg_proc_open_devstrs,
2357 	.read = seq_read,
2358 	.llseek = seq_lseek,
2359 	.release = seq_release,
2360 };
2361 static const struct seq_operations devstrs_seq_ops = {
2362 	.start = dev_seq_start,
2363 	.next  = dev_seq_next,
2364 	.stop  = dev_seq_stop,
2365 	.show  = sg_proc_seq_show_devstrs,
2366 };
2367 
2368 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2369 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2370 static const struct file_operations debug_fops = {
2371 	.owner = THIS_MODULE,
2372 	.open = sg_proc_open_debug,
2373 	.read = seq_read,
2374 	.llseek = seq_lseek,
2375 	.release = seq_release,
2376 };
2377 static const struct seq_operations debug_seq_ops = {
2378 	.start = dev_seq_start,
2379 	.next  = dev_seq_next,
2380 	.stop  = dev_seq_stop,
2381 	.show  = sg_proc_seq_show_debug,
2382 };
2383 
2384 
2385 struct sg_proc_leaf {
2386 	const char * name;
2387 	const struct file_operations * fops;
2388 };
2389 
2390 static const struct sg_proc_leaf sg_proc_leaf_arr[] = {
2391 	{"allow_dio", &adio_fops},
2392 	{"debug", &debug_fops},
2393 	{"def_reserved_size", &dressz_fops},
2394 	{"device_hdr", &devhdr_fops},
2395 	{"devices", &dev_fops},
2396 	{"device_strs", &devstrs_fops},
2397 	{"version", &version_fops}
2398 };
2399 
2400 static int
2401 sg_proc_init(void)
2402 {
2403 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2404 	int k;
2405 
2406 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2407 	if (!sg_proc_sgp)
2408 		return 1;
2409 	for (k = 0; k < num_leaves; ++k) {
2410 		const struct sg_proc_leaf *leaf = &sg_proc_leaf_arr[k];
2411 		umode_t mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2412 		proc_create(leaf->name, mask, sg_proc_sgp, leaf->fops);
2413 	}
2414 	return 0;
2415 }
2416 
2417 static void
2418 sg_proc_cleanup(void)
2419 {
2420 	int k;
2421 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2422 
2423 	if (!sg_proc_sgp)
2424 		return;
2425 	for (k = 0; k < num_leaves; ++k)
2426 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2427 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2428 }
2429 
2430 
2431 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2432 {
2433 	seq_printf(s, "%d\n", *((int *)s->private));
2434 	return 0;
2435 }
2436 
2437 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2438 {
2439 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2440 }
2441 
2442 static ssize_t
2443 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2444 		   size_t count, loff_t *off)
2445 {
2446 	int err;
2447 	unsigned long num;
2448 
2449 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2450 		return -EACCES;
2451 	err = kstrtoul_from_user(buffer, count, 0, &num);
2452 	if (err)
2453 		return err;
2454 	sg_allow_dio = num ? 1 : 0;
2455 	return count;
2456 }
2457 
2458 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2459 {
2460 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2461 }
2462 
2463 static ssize_t
2464 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2465 		     size_t count, loff_t *off)
2466 {
2467 	int err;
2468 	unsigned long k = ULONG_MAX;
2469 
2470 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2471 		return -EACCES;
2472 
2473 	err = kstrtoul_from_user(buffer, count, 0, &k);
2474 	if (err)
2475 		return err;
2476 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2477 		sg_big_buff = k;
2478 		return count;
2479 	}
2480 	return -ERANGE;
2481 }
2482 
2483 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2484 {
2485 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2486 		   sg_version_date);
2487 	return 0;
2488 }
2489 
2490 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2491 {
2492 	return single_open(file, sg_proc_seq_show_version, NULL);
2493 }
2494 
2495 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2496 {
2497 	seq_puts(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\tonline\n");
2498 	return 0;
2499 }
2500 
2501 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2502 {
2503 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2504 }
2505 
2506 struct sg_proc_deviter {
2507 	loff_t	index;
2508 	size_t	max;
2509 };
2510 
2511 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2512 {
2513 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2514 
2515 	s->private = it;
2516 	if (! it)
2517 		return NULL;
2518 
2519 	it->index = *pos;
2520 	it->max = sg_last_dev();
2521 	if (it->index >= it->max)
2522 		return NULL;
2523 	return it;
2524 }
2525 
2526 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2527 {
2528 	struct sg_proc_deviter * it = s->private;
2529 
2530 	*pos = ++it->index;
2531 	return (it->index < it->max) ? it : NULL;
2532 }
2533 
2534 static void dev_seq_stop(struct seq_file *s, void *v)
2535 {
2536 	kfree(s->private);
2537 }
2538 
2539 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2540 {
2541         return seq_open(file, &dev_seq_ops);
2542 }
2543 
2544 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2545 {
2546 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2547 	Sg_device *sdp;
2548 	struct scsi_device *scsidp;
2549 	unsigned long iflags;
2550 
2551 	read_lock_irqsave(&sg_index_lock, iflags);
2552 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2553 	if ((NULL == sdp) || (NULL == sdp->device) ||
2554 	    (atomic_read(&sdp->detaching)))
2555 		seq_puts(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2556 	else {
2557 		scsidp = sdp->device;
2558 		seq_printf(s, "%d\t%d\t%d\t%llu\t%d\t%d\t%d\t%d\t%d\n",
2559 			      scsidp->host->host_no, scsidp->channel,
2560 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2561 			      1,
2562 			      (int) scsidp->queue_depth,
2563 			      (int) atomic_read(&scsidp->device_busy),
2564 			      (int) scsi_device_online(scsidp));
2565 	}
2566 	read_unlock_irqrestore(&sg_index_lock, iflags);
2567 	return 0;
2568 }
2569 
2570 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2571 {
2572         return seq_open(file, &devstrs_seq_ops);
2573 }
2574 
2575 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2576 {
2577 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2578 	Sg_device *sdp;
2579 	struct scsi_device *scsidp;
2580 	unsigned long iflags;
2581 
2582 	read_lock_irqsave(&sg_index_lock, iflags);
2583 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2584 	scsidp = sdp ? sdp->device : NULL;
2585 	if (sdp && scsidp && (!atomic_read(&sdp->detaching)))
2586 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2587 			   scsidp->vendor, scsidp->model, scsidp->rev);
2588 	else
2589 		seq_puts(s, "<no active device>\n");
2590 	read_unlock_irqrestore(&sg_index_lock, iflags);
2591 	return 0;
2592 }
2593 
2594 /* must be called while holding sg_index_lock */
2595 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2596 {
2597 	int k, m, new_interface, blen, usg;
2598 	Sg_request *srp;
2599 	Sg_fd *fp;
2600 	const sg_io_hdr_t *hp;
2601 	const char * cp;
2602 	unsigned int ms;
2603 
2604 	k = 0;
2605 	list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2606 		k++;
2607 		read_lock(&fp->rq_list_lock); /* irqs already disabled */
2608 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2609 			   "(res)sgat=%d low_dma=%d\n", k,
2610 			   jiffies_to_msecs(fp->timeout),
2611 			   fp->reserve.bufflen,
2612 			   (int) fp->reserve.k_use_sg,
2613 			   (int) fp->low_dma);
2614 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
2615 			   (int) fp->cmd_q, (int) fp->force_packid,
2616 			   (int) fp->keep_orphan);
2617 		for (m = 0, srp = fp->headrp;
2618 				srp != NULL;
2619 				++m, srp = srp->nextrp) {
2620 			hp = &srp->header;
2621 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2622 			if (srp->res_used) {
2623 				if (new_interface &&
2624 				    (SG_FLAG_MMAP_IO & hp->flags))
2625 					cp = "     mmap>> ";
2626 				else
2627 					cp = "     rb>> ";
2628 			} else {
2629 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2630 					cp = "     dio>> ";
2631 				else
2632 					cp = "     ";
2633 			}
2634 			seq_puts(s, cp);
2635 			blen = srp->data.bufflen;
2636 			usg = srp->data.k_use_sg;
2637 			seq_puts(s, srp->done ?
2638 				 ((1 == srp->done) ?  "rcv:" : "fin:")
2639 				  : "act:");
2640 			seq_printf(s, " id=%d blen=%d",
2641 				   srp->header.pack_id, blen);
2642 			if (srp->done)
2643 				seq_printf(s, " dur=%d", hp->duration);
2644 			else {
2645 				ms = jiffies_to_msecs(jiffies);
2646 				seq_printf(s, " t_o/elap=%d/%d",
2647 					(new_interface ? hp->timeout :
2648 						  jiffies_to_msecs(fp->timeout)),
2649 					(ms > hp->duration ? ms - hp->duration : 0));
2650 			}
2651 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2652 				   (int) srp->data.cmd_opcode);
2653 		}
2654 		if (0 == m)
2655 			seq_puts(s, "     No requests active\n");
2656 		read_unlock(&fp->rq_list_lock);
2657 	}
2658 }
2659 
2660 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2661 {
2662         return seq_open(file, &debug_seq_ops);
2663 }
2664 
2665 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2666 {
2667 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2668 	Sg_device *sdp;
2669 	unsigned long iflags;
2670 
2671 	if (it && (0 == it->index))
2672 		seq_printf(s, "max_active_device=%d  def_reserved_size=%d\n",
2673 			   (int)it->max, sg_big_buff);
2674 
2675 	read_lock_irqsave(&sg_index_lock, iflags);
2676 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2677 	if (NULL == sdp)
2678 		goto skip;
2679 	read_lock(&sdp->sfd_lock);
2680 	if (!list_empty(&sdp->sfds)) {
2681 		seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2682 		if (atomic_read(&sdp->detaching))
2683 			seq_puts(s, "detaching pending close ");
2684 		else if (sdp->device) {
2685 			struct scsi_device *scsidp = sdp->device;
2686 
2687 			seq_printf(s, "%d:%d:%d:%llu   em=%d",
2688 				   scsidp->host->host_no,
2689 				   scsidp->channel, scsidp->id,
2690 				   scsidp->lun,
2691 				   scsidp->host->hostt->emulated);
2692 		}
2693 		seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
2694 			   sdp->sg_tablesize, sdp->exclude, sdp->open_cnt);
2695 		sg_proc_debug_helper(s, sdp);
2696 	}
2697 	read_unlock(&sdp->sfd_lock);
2698 skip:
2699 	read_unlock_irqrestore(&sg_index_lock, iflags);
2700 	return 0;
2701 }
2702 
2703 #endif				/* CONFIG_SCSI_PROC_FS */
2704 
2705 module_init(init_sg);
2706 module_exit(exit_sg);
2707