xref: /openbmc/linux/drivers/scsi/sg.c (revision dea54fba)
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 list_head entry;	/* list entry */
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 	struct mutex f_mutex;	/* protect against changes in this fd */
146 	int timeout;		/* defaults to SG_DEFAULT_TIMEOUT      */
147 	int timeout_user;	/* defaults to SG_DEFAULT_TIMEOUT_USER */
148 	Sg_scatter_hold reserve;	/* buffer held for this file descriptor */
149 	struct list_head rq_list; /* head of request list */
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 force_packid;	/* 1 -> pack_id input to read(), 0 -> ignored */
153 	char cmd_q;		/* 1 -> allow command queuing, 0 -> don't */
154 	unsigned char next_cmd_len; /* 0: automatic, >0: use on next write() */
155 	char keep_orphan;	/* 0 -> drop orphan (def), 1 -> keep for read() */
156 	char mmap_called;	/* 0 -> mmap() never called on this fd */
157 	char res_in_use;	/* 1 -> 'reserve' array in use */
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, blk_status_t status);
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 Sg_device *sg_get_dev(int dev);
202 static void sg_device_destroy(struct kref *kref);
203 
204 #define SZ_SG_HEADER sizeof(struct sg_header)
205 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
206 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
207 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
208 
209 #define sg_printk(prefix, sdp, fmt, a...) \
210 	sdev_prefix_printk(prefix, (sdp)->device,		\
211 			   (sdp)->disk->disk_name, fmt, ##a)
212 
213 static int sg_allow_access(struct file *filp, unsigned char *cmd)
214 {
215 	struct sg_fd *sfp = filp->private_data;
216 
217 	if (sfp->parentdp->device->type == TYPE_SCANNER)
218 		return 0;
219 
220 	return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
221 }
222 
223 static int
224 open_wait(Sg_device *sdp, int flags)
225 {
226 	int retval = 0;
227 
228 	if (flags & O_EXCL) {
229 		while (sdp->open_cnt > 0) {
230 			mutex_unlock(&sdp->open_rel_lock);
231 			retval = wait_event_interruptible(sdp->open_wait,
232 					(atomic_read(&sdp->detaching) ||
233 					 !sdp->open_cnt));
234 			mutex_lock(&sdp->open_rel_lock);
235 
236 			if (retval) /* -ERESTARTSYS */
237 				return retval;
238 			if (atomic_read(&sdp->detaching))
239 				return -ENODEV;
240 		}
241 	} else {
242 		while (sdp->exclude) {
243 			mutex_unlock(&sdp->open_rel_lock);
244 			retval = wait_event_interruptible(sdp->open_wait,
245 					(atomic_read(&sdp->detaching) ||
246 					 !sdp->exclude));
247 			mutex_lock(&sdp->open_rel_lock);
248 
249 			if (retval) /* -ERESTARTSYS */
250 				return retval;
251 			if (atomic_read(&sdp->detaching))
252 				return -ENODEV;
253 		}
254 	}
255 
256 	return retval;
257 }
258 
259 /* Returns 0 on success, else a negated errno value */
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 retval;
269 
270 	nonseekable_open(inode, filp);
271 	if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE)))
272 		return -EPERM; /* Can't lock it with read only access */
273 	sdp = sg_get_dev(dev);
274 	if (IS_ERR(sdp))
275 		return PTR_ERR(sdp);
276 
277 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
278 				      "sg_open: flags=0x%x\n", flags));
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 	/* scsi_block_when_processing_errors() may block so bypass
291 	 * check if O_NONBLOCK. Permits SCSI commands to be issued
292 	 * during error recovery. Tread carefully. */
293 	if (!((flags & O_NONBLOCK) ||
294 	      scsi_block_when_processing_errors(sdp->device))) {
295 		retval = -ENXIO;
296 		/* we are in error recovery for this device */
297 		goto error_out;
298 	}
299 
300 	mutex_lock(&sdp->open_rel_lock);
301 	if (flags & O_NONBLOCK) {
302 		if (flags & O_EXCL) {
303 			if (sdp->open_cnt > 0) {
304 				retval = -EBUSY;
305 				goto error_mutex_locked;
306 			}
307 		} else {
308 			if (sdp->exclude) {
309 				retval = -EBUSY;
310 				goto error_mutex_locked;
311 			}
312 		}
313 	} else {
314 		retval = open_wait(sdp, flags);
315 		if (retval) /* -ERESTARTSYS or -ENODEV */
316 			goto error_mutex_locked;
317 	}
318 
319 	/* N.B. at this point we are holding the open_rel_lock */
320 	if (flags & O_EXCL)
321 		sdp->exclude = true;
322 
323 	if (sdp->open_cnt < 1) {  /* no existing opens */
324 		sdp->sgdebug = 0;
325 		q = sdp->device->request_queue;
326 		sdp->sg_tablesize = queue_max_segments(q);
327 	}
328 	sfp = sg_add_sfp(sdp);
329 	if (IS_ERR(sfp)) {
330 		retval = PTR_ERR(sfp);
331 		goto out_undo;
332 	}
333 
334 	filp->private_data = sfp;
335 	sdp->open_cnt++;
336 	mutex_unlock(&sdp->open_rel_lock);
337 
338 	retval = 0;
339 sg_put:
340 	kref_put(&sdp->d_ref, sg_device_destroy);
341 	return retval;
342 
343 out_undo:
344 	if (flags & O_EXCL) {
345 		sdp->exclude = false;   /* undo if error */
346 		wake_up_interruptible(&sdp->open_wait);
347 	}
348 error_mutex_locked:
349 	mutex_unlock(&sdp->open_rel_lock);
350 error_out:
351 	scsi_autopm_put_device(sdp->device);
352 sdp_put:
353 	scsi_device_put(sdp->device);
354 	goto sg_put;
355 }
356 
357 /* Release resources associated with a successful sg_open()
358  * Returns 0 on success, else a negated errno value */
359 static int
360 sg_release(struct inode *inode, struct file *filp)
361 {
362 	Sg_device *sdp;
363 	Sg_fd *sfp;
364 
365 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
366 		return -ENXIO;
367 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n"));
368 
369 	mutex_lock(&sdp->open_rel_lock);
370 	scsi_autopm_put_device(sdp->device);
371 	kref_put(&sfp->f_ref, sg_remove_sfp);
372 	sdp->open_cnt--;
373 
374 	/* possibly many open()s waiting on exlude clearing, start many;
375 	 * only open(O_EXCL)s wait on 0==open_cnt so only start one */
376 	if (sdp->exclude) {
377 		sdp->exclude = false;
378 		wake_up_interruptible_all(&sdp->open_wait);
379 	} else if (0 == sdp->open_cnt) {
380 		wake_up_interruptible(&sdp->open_wait);
381 	}
382 	mutex_unlock(&sdp->open_rel_lock);
383 	return 0;
384 }
385 
386 static ssize_t
387 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
388 {
389 	Sg_device *sdp;
390 	Sg_fd *sfp;
391 	Sg_request *srp;
392 	int req_pack_id = -1;
393 	sg_io_hdr_t *hp;
394 	struct sg_header *old_hdr = NULL;
395 	int retval = 0;
396 
397 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
398 		return -ENXIO;
399 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
400 				      "sg_read: count=%d\n", (int) count));
401 
402 	if (!access_ok(VERIFY_WRITE, buf, count))
403 		return -EFAULT;
404 	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
405 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
406 		if (!old_hdr)
407 			return -ENOMEM;
408 		if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
409 			retval = -EFAULT;
410 			goto free_old_hdr;
411 		}
412 		if (old_hdr->reply_len < 0) {
413 			if (count >= SZ_SG_IO_HDR) {
414 				sg_io_hdr_t *new_hdr;
415 				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
416 				if (!new_hdr) {
417 					retval = -ENOMEM;
418 					goto free_old_hdr;
419 				}
420 				retval =__copy_from_user
421 				    (new_hdr, buf, SZ_SG_IO_HDR);
422 				req_pack_id = new_hdr->pack_id;
423 				kfree(new_hdr);
424 				if (retval) {
425 					retval = -EFAULT;
426 					goto free_old_hdr;
427 				}
428 			}
429 		} else
430 			req_pack_id = old_hdr->pack_id;
431 	}
432 	srp = sg_get_rq_mark(sfp, req_pack_id);
433 	if (!srp) {		/* now wait on packet to arrive */
434 		if (atomic_read(&sdp->detaching)) {
435 			retval = -ENODEV;
436 			goto free_old_hdr;
437 		}
438 		if (filp->f_flags & O_NONBLOCK) {
439 			retval = -EAGAIN;
440 			goto free_old_hdr;
441 		}
442 		retval = wait_event_interruptible(sfp->read_wait,
443 			(atomic_read(&sdp->detaching) ||
444 			(srp = sg_get_rq_mark(sfp, req_pack_id))));
445 		if (atomic_read(&sdp->detaching)) {
446 			retval = -ENODEV;
447 			goto free_old_hdr;
448 		}
449 		if (retval) {
450 			/* -ERESTARTSYS as signal hit process */
451 			goto free_old_hdr;
452 		}
453 	}
454 	if (srp->header.interface_id != '\0') {
455 		retval = sg_new_read(sfp, buf, count, srp);
456 		goto free_old_hdr;
457 	}
458 
459 	hp = &srp->header;
460 	if (old_hdr == NULL) {
461 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
462 		if (! old_hdr) {
463 			retval = -ENOMEM;
464 			goto free_old_hdr;
465 		}
466 	}
467 	memset(old_hdr, 0, SZ_SG_HEADER);
468 	old_hdr->reply_len = (int) hp->timeout;
469 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
470 	old_hdr->pack_id = hp->pack_id;
471 	old_hdr->twelve_byte =
472 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
473 	old_hdr->target_status = hp->masked_status;
474 	old_hdr->host_status = hp->host_status;
475 	old_hdr->driver_status = hp->driver_status;
476 	if ((CHECK_CONDITION & hp->masked_status) ||
477 	    (DRIVER_SENSE & hp->driver_status))
478 		memcpy(old_hdr->sense_buffer, srp->sense_b,
479 		       sizeof (old_hdr->sense_buffer));
480 	switch (hp->host_status) {
481 	/* This setup of 'result' is for backward compatibility and is best
482 	   ignored by the user who should use target, host + driver status */
483 	case DID_OK:
484 	case DID_PASSTHROUGH:
485 	case DID_SOFT_ERROR:
486 		old_hdr->result = 0;
487 		break;
488 	case DID_NO_CONNECT:
489 	case DID_BUS_BUSY:
490 	case DID_TIME_OUT:
491 		old_hdr->result = EBUSY;
492 		break;
493 	case DID_BAD_TARGET:
494 	case DID_ABORT:
495 	case DID_PARITY:
496 	case DID_RESET:
497 	case DID_BAD_INTR:
498 		old_hdr->result = EIO;
499 		break;
500 	case DID_ERROR:
501 		old_hdr->result = (srp->sense_b[0] == 0 &&
502 				  hp->masked_status == GOOD) ? 0 : EIO;
503 		break;
504 	default:
505 		old_hdr->result = EIO;
506 		break;
507 	}
508 
509 	/* Now copy the result back to the user buffer.  */
510 	if (count >= SZ_SG_HEADER) {
511 		if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
512 			retval = -EFAULT;
513 			goto free_old_hdr;
514 		}
515 		buf += SZ_SG_HEADER;
516 		if (count > old_hdr->reply_len)
517 			count = old_hdr->reply_len;
518 		if (count > SZ_SG_HEADER) {
519 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
520 				retval = -EFAULT;
521 				goto free_old_hdr;
522 			}
523 		}
524 	} else
525 		count = (old_hdr->result == 0) ? 0 : -EIO;
526 	sg_finish_rem_req(srp);
527 	sg_remove_request(sfp, 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 	sg_remove_request(sfp, srp);
569 	return err ? : err2 ? : count;
570 }
571 
572 static ssize_t
573 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
574 {
575 	int mxsize, cmd_size, k;
576 	int input_size, blocking;
577 	unsigned char opcode;
578 	Sg_device *sdp;
579 	Sg_fd *sfp;
580 	Sg_request *srp;
581 	struct sg_header old_hdr;
582 	sg_io_hdr_t *hp;
583 	unsigned char cmnd[SG_MAX_CDB_SIZE];
584 
585 	if (unlikely(uaccess_kernel()))
586 		return -EINVAL;
587 
588 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
589 		return -ENXIO;
590 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
591 				      "sg_write: count=%d\n", (int) count));
592 	if (atomic_read(&sdp->detaching))
593 		return -ENODEV;
594 	if (!((filp->f_flags & O_NONBLOCK) ||
595 	      scsi_block_when_processing_errors(sdp->device)))
596 		return -ENXIO;
597 
598 	if (!access_ok(VERIFY_READ, buf, count))
599 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
600 	if (count < SZ_SG_HEADER)
601 		return -EIO;
602 	if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
603 		return -EFAULT;
604 	blocking = !(filp->f_flags & O_NONBLOCK);
605 	if (old_hdr.reply_len < 0)
606 		return sg_new_write(sfp, filp, buf, count,
607 				    blocking, 0, 0, NULL);
608 	if (count < (SZ_SG_HEADER + 6))
609 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
610 
611 	if (!(srp = sg_add_request(sfp))) {
612 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sdp,
613 					      "sg_write: queue full\n"));
614 		return -EDOM;
615 	}
616 	buf += SZ_SG_HEADER;
617 	__get_user(opcode, buf);
618 	mutex_lock(&sfp->f_mutex);
619 	if (sfp->next_cmd_len > 0) {
620 		cmd_size = sfp->next_cmd_len;
621 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
622 	} else {
623 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
624 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
625 			cmd_size = 12;
626 	}
627 	mutex_unlock(&sfp->f_mutex);
628 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
629 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
630 /* Determine buffer size.  */
631 	input_size = count - cmd_size;
632 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
633 	mxsize -= SZ_SG_HEADER;
634 	input_size -= SZ_SG_HEADER;
635 	if (input_size < 0) {
636 		sg_remove_request(sfp, srp);
637 		return -EIO;	/* User did not pass enough bytes for this command. */
638 	}
639 	hp = &srp->header;
640 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
641 	hp->cmd_len = (unsigned char) cmd_size;
642 	hp->iovec_count = 0;
643 	hp->mx_sb_len = 0;
644 	if (input_size > 0)
645 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
646 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
647 	else
648 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
649 	hp->dxfer_len = mxsize;
650 	if ((hp->dxfer_direction == SG_DXFER_TO_DEV) ||
651 	    (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV))
652 		hp->dxferp = (char __user *)buf + cmd_size;
653 	else
654 		hp->dxferp = NULL;
655 	hp->sbp = NULL;
656 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
657 	hp->flags = input_size;	/* structure abuse ... */
658 	hp->pack_id = old_hdr.pack_id;
659 	hp->usr_ptr = NULL;
660 	if (__copy_from_user(cmnd, buf, cmd_size))
661 		return -EFAULT;
662 	/*
663 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
664 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
665 	 * is a non-zero input_size, so emit a warning.
666 	 */
667 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
668 		printk_ratelimited(KERN_WARNING
669 				   "sg_write: data in/out %d/%d bytes "
670 				   "for SCSI command 0x%x-- guessing "
671 				   "data in;\n   program %s not setting "
672 				   "count and/or reply_len properly\n",
673 				   old_hdr.reply_len - (int)SZ_SG_HEADER,
674 				   input_size, (unsigned int) cmnd[0],
675 				   current->comm);
676 	}
677 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
678 	return (k < 0) ? k : count;
679 }
680 
681 static ssize_t
682 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
683 		 size_t count, int blocking, int read_only, int sg_io_owned,
684 		 Sg_request **o_srp)
685 {
686 	int k;
687 	Sg_request *srp;
688 	sg_io_hdr_t *hp;
689 	unsigned char cmnd[SG_MAX_CDB_SIZE];
690 	int timeout;
691 	unsigned long ul_timeout;
692 
693 	if (count < SZ_SG_IO_HDR)
694 		return -EINVAL;
695 	if (!access_ok(VERIFY_READ, buf, count))
696 		return -EFAULT; /* protects following copy_from_user()s + get_user()s */
697 
698 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
699 	if (!(srp = sg_add_request(sfp))) {
700 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
701 					      "sg_new_write: queue full\n"));
702 		return -EDOM;
703 	}
704 	srp->sg_io_owned = sg_io_owned;
705 	hp = &srp->header;
706 	if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
707 		sg_remove_request(sfp, srp);
708 		return -EFAULT;
709 	}
710 	if (hp->interface_id != 'S') {
711 		sg_remove_request(sfp, srp);
712 		return -ENOSYS;
713 	}
714 	if (hp->flags & SG_FLAG_MMAP_IO) {
715 		if (hp->dxfer_len > sfp->reserve.bufflen) {
716 			sg_remove_request(sfp, srp);
717 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
718 		}
719 		if (hp->flags & SG_FLAG_DIRECT_IO) {
720 			sg_remove_request(sfp, srp);
721 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
722 		}
723 		if (sfp->res_in_use) {
724 			sg_remove_request(sfp, srp);
725 			return -EBUSY;	/* reserve buffer already being used */
726 		}
727 	}
728 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
729 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
730 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
731 		sg_remove_request(sfp, srp);
732 		return -EMSGSIZE;
733 	}
734 	if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
735 		sg_remove_request(sfp, srp);
736 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
737 	}
738 	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
739 		sg_remove_request(sfp, srp);
740 		return -EFAULT;
741 	}
742 	if (read_only && sg_allow_access(file, cmnd)) {
743 		sg_remove_request(sfp, srp);
744 		return -EPERM;
745 	}
746 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
747 	if (k < 0)
748 		return k;
749 	if (o_srp)
750 		*o_srp = srp;
751 	return count;
752 }
753 
754 static int
755 sg_common_write(Sg_fd * sfp, Sg_request * srp,
756 		unsigned char *cmnd, int timeout, int blocking)
757 {
758 	int k, at_head;
759 	Sg_device *sdp = sfp->parentdp;
760 	sg_io_hdr_t *hp = &srp->header;
761 
762 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
763 	hp->status = 0;
764 	hp->masked_status = 0;
765 	hp->msg_status = 0;
766 	hp->info = 0;
767 	hp->host_status = 0;
768 	hp->driver_status = 0;
769 	hp->resid = 0;
770 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
771 			"sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
772 			(int) cmnd[0], (int) hp->cmd_len));
773 
774 	if (hp->dxfer_len >= SZ_256M)
775 		return -EINVAL;
776 
777 	k = sg_start_req(srp, cmnd);
778 	if (k) {
779 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
780 			"sg_common_write: start_req err=%d\n", k));
781 		sg_finish_rem_req(srp);
782 		sg_remove_request(sfp, srp);
783 		return k;	/* probably out of space --> ENOMEM */
784 	}
785 	if (atomic_read(&sdp->detaching)) {
786 		if (srp->bio) {
787 			scsi_req_free_cmd(scsi_req(srp->rq));
788 			blk_end_request_all(srp->rq, BLK_STS_IOERR);
789 			srp->rq = NULL;
790 		}
791 
792 		sg_finish_rem_req(srp);
793 		sg_remove_request(sfp, srp);
794 		return -ENODEV;
795 	}
796 
797 	hp->duration = jiffies_to_msecs(jiffies);
798 	if (hp->interface_id != '\0' &&	/* v3 (or later) interface */
799 	    (SG_FLAG_Q_AT_TAIL & hp->flags))
800 		at_head = 0;
801 	else
802 		at_head = 1;
803 
804 	srp->rq->timeout = timeout;
805 	kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
806 	blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
807 			      srp->rq, at_head, sg_rq_end_io);
808 	return 0;
809 }
810 
811 static int srp_done(Sg_fd *sfp, Sg_request *srp)
812 {
813 	unsigned long flags;
814 	int ret;
815 
816 	read_lock_irqsave(&sfp->rq_list_lock, flags);
817 	ret = srp->done;
818 	read_unlock_irqrestore(&sfp->rq_list_lock, flags);
819 	return ret;
820 }
821 
822 static int max_sectors_bytes(struct request_queue *q)
823 {
824 	unsigned int max_sectors = queue_max_sectors(q);
825 
826 	max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
827 
828 	return max_sectors << 9;
829 }
830 
831 static long
832 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
833 {
834 	void __user *p = (void __user *)arg;
835 	int __user *ip = p;
836 	int result, val, read_only;
837 	Sg_device *sdp;
838 	Sg_fd *sfp;
839 	Sg_request *srp;
840 	unsigned long iflags;
841 
842 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
843 		return -ENXIO;
844 
845 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
846 				   "sg_ioctl: cmd=0x%x\n", (int) cmd_in));
847 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
848 
849 	switch (cmd_in) {
850 	case SG_IO:
851 		if (atomic_read(&sdp->detaching))
852 			return -ENODEV;
853 		if (!scsi_block_when_processing_errors(sdp->device))
854 			return -ENXIO;
855 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
856 			return -EFAULT;
857 		result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
858 				 1, read_only, 1, &srp);
859 		if (result < 0)
860 			return result;
861 		result = wait_event_interruptible(sfp->read_wait,
862 			(srp_done(sfp, srp) || atomic_read(&sdp->detaching)));
863 		if (atomic_read(&sdp->detaching))
864 			return -ENODEV;
865 		write_lock_irq(&sfp->rq_list_lock);
866 		if (srp->done) {
867 			srp->done = 2;
868 			write_unlock_irq(&sfp->rq_list_lock);
869 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
870 			return (result < 0) ? result : 0;
871 		}
872 		srp->orphan = 1;
873 		write_unlock_irq(&sfp->rq_list_lock);
874 		return result;	/* -ERESTARTSYS because signal hit process */
875 	case SG_SET_TIMEOUT:
876 		result = get_user(val, ip);
877 		if (result)
878 			return result;
879 		if (val < 0)
880 			return -EIO;
881 		if (val >= mult_frac((s64)INT_MAX, USER_HZ, HZ))
882 			val = min_t(s64, mult_frac((s64)INT_MAX, USER_HZ, HZ),
883 				    INT_MAX);
884 		sfp->timeout_user = val;
885 		sfp->timeout = mult_frac(val, HZ, USER_HZ);
886 
887 		return 0;
888 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
889 				/* strange ..., for backward compatibility */
890 		return sfp->timeout_user;
891 	case SG_SET_FORCE_LOW_DMA:
892 		/*
893 		 * N.B. This ioctl never worked properly, but failed to
894 		 * return an error value. So returning '0' to keep compability
895 		 * with legacy applications.
896 		 */
897 		return 0;
898 	case SG_GET_LOW_DMA:
899 		return put_user((int) sdp->device->host->unchecked_isa_dma, ip);
900 	case SG_GET_SCSI_ID:
901 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
902 			return -EFAULT;
903 		else {
904 			sg_scsi_id_t __user *sg_idp = p;
905 
906 			if (atomic_read(&sdp->detaching))
907 				return -ENODEV;
908 			__put_user((int) sdp->device->host->host_no,
909 				   &sg_idp->host_no);
910 			__put_user((int) sdp->device->channel,
911 				   &sg_idp->channel);
912 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
913 			__put_user((int) sdp->device->lun, &sg_idp->lun);
914 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
915 			__put_user((short) sdp->device->host->cmd_per_lun,
916 				   &sg_idp->h_cmd_per_lun);
917 			__put_user((short) sdp->device->queue_depth,
918 				   &sg_idp->d_queue_depth);
919 			__put_user(0, &sg_idp->unused[0]);
920 			__put_user(0, &sg_idp->unused[1]);
921 			return 0;
922 		}
923 	case SG_SET_FORCE_PACK_ID:
924 		result = get_user(val, ip);
925 		if (result)
926 			return result;
927 		sfp->force_packid = val ? 1 : 0;
928 		return 0;
929 	case SG_GET_PACK_ID:
930 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
931 			return -EFAULT;
932 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
933 		list_for_each_entry(srp, &sfp->rq_list, entry) {
934 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
935 				read_unlock_irqrestore(&sfp->rq_list_lock,
936 						       iflags);
937 				__put_user(srp->header.pack_id, ip);
938 				return 0;
939 			}
940 		}
941 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
942 		__put_user(-1, ip);
943 		return 0;
944 	case SG_GET_NUM_WAITING:
945 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
946 		val = 0;
947 		list_for_each_entry(srp, &sfp->rq_list, entry) {
948 			if ((1 == srp->done) && (!srp->sg_io_owned))
949 				++val;
950 		}
951 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
952 		return put_user(val, ip);
953 	case SG_GET_SG_TABLESIZE:
954 		return put_user(sdp->sg_tablesize, ip);
955 	case SG_SET_RESERVED_SIZE:
956 		result = get_user(val, ip);
957 		if (result)
958 			return result;
959                 if (val < 0)
960                         return -EINVAL;
961 		val = min_t(int, val,
962 			    max_sectors_bytes(sdp->device->request_queue));
963 		mutex_lock(&sfp->f_mutex);
964 		if (val != sfp->reserve.bufflen) {
965 			if (sfp->mmap_called ||
966 			    sfp->res_in_use) {
967 				mutex_unlock(&sfp->f_mutex);
968 				return -EBUSY;
969 			}
970 
971 			sg_remove_scat(sfp, &sfp->reserve);
972 			sg_build_reserve(sfp, val);
973 		}
974 		mutex_unlock(&sfp->f_mutex);
975 		return 0;
976 	case SG_GET_RESERVED_SIZE:
977 		val = min_t(int, sfp->reserve.bufflen,
978 			    max_sectors_bytes(sdp->device->request_queue));
979 		return put_user(val, ip);
980 	case SG_SET_COMMAND_Q:
981 		result = get_user(val, ip);
982 		if (result)
983 			return result;
984 		sfp->cmd_q = val ? 1 : 0;
985 		return 0;
986 	case SG_GET_COMMAND_Q:
987 		return put_user((int) sfp->cmd_q, ip);
988 	case SG_SET_KEEP_ORPHAN:
989 		result = get_user(val, ip);
990 		if (result)
991 			return result;
992 		sfp->keep_orphan = val;
993 		return 0;
994 	case SG_GET_KEEP_ORPHAN:
995 		return put_user((int) sfp->keep_orphan, ip);
996 	case SG_NEXT_CMD_LEN:
997 		result = get_user(val, ip);
998 		if (result)
999 			return result;
1000 		if (val > SG_MAX_CDB_SIZE)
1001 			return -ENOMEM;
1002 		sfp->next_cmd_len = (val > 0) ? val : 0;
1003 		return 0;
1004 	case SG_GET_VERSION_NUM:
1005 		return put_user(sg_version_num, ip);
1006 	case SG_GET_ACCESS_COUNT:
1007 		/* faked - we don't have a real access count anymore */
1008 		val = (sdp->device ? 1 : 0);
1009 		return put_user(val, ip);
1010 	case SG_GET_REQUEST_TABLE:
1011 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
1012 			return -EFAULT;
1013 		else {
1014 			sg_req_info_t *rinfo;
1015 			unsigned int ms;
1016 
1017 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
1018 								GFP_KERNEL);
1019 			if (!rinfo)
1020 				return -ENOMEM;
1021 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
1022 			val = 0;
1023 			list_for_each_entry(srp, &sfp->rq_list, entry) {
1024 				if (val > SG_MAX_QUEUE)
1025 					break;
1026 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
1027 				rinfo[val].req_state = srp->done + 1;
1028 				rinfo[val].problem =
1029 					srp->header.masked_status &
1030 					srp->header.host_status &
1031 					srp->header.driver_status;
1032 				if (srp->done)
1033 					rinfo[val].duration =
1034 						srp->header.duration;
1035 				else {
1036 					ms = jiffies_to_msecs(jiffies);
1037 					rinfo[val].duration =
1038 						(ms > srp->header.duration) ?
1039 						(ms - srp->header.duration) : 0;
1040 				}
1041 				rinfo[val].orphan = srp->orphan;
1042 				rinfo[val].sg_io_owned = srp->sg_io_owned;
1043 				rinfo[val].pack_id = srp->header.pack_id;
1044 				rinfo[val].usr_ptr = srp->header.usr_ptr;
1045 				val++;
1046 			}
1047 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1048 			result = __copy_to_user(p, rinfo,
1049 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1050 			result = result ? -EFAULT : 0;
1051 			kfree(rinfo);
1052 			return result;
1053 		}
1054 	case SG_EMULATED_HOST:
1055 		if (atomic_read(&sdp->detaching))
1056 			return -ENODEV;
1057 		return put_user(sdp->device->host->hostt->emulated, ip);
1058 	case SCSI_IOCTL_SEND_COMMAND:
1059 		if (atomic_read(&sdp->detaching))
1060 			return -ENODEV;
1061 		if (read_only) {
1062 			unsigned char opcode = WRITE_6;
1063 			Scsi_Ioctl_Command __user *siocp = p;
1064 
1065 			if (copy_from_user(&opcode, siocp->data, 1))
1066 				return -EFAULT;
1067 			if (sg_allow_access(filp, &opcode))
1068 				return -EPERM;
1069 		}
1070 		return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1071 	case SG_SET_DEBUG:
1072 		result = get_user(val, ip);
1073 		if (result)
1074 			return result;
1075 		sdp->sgdebug = (char) val;
1076 		return 0;
1077 	case BLKSECTGET:
1078 		return put_user(max_sectors_bytes(sdp->device->request_queue),
1079 				ip);
1080 	case BLKTRACESETUP:
1081 		return blk_trace_setup(sdp->device->request_queue,
1082 				       sdp->disk->disk_name,
1083 				       MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1084 				       NULL,
1085 				       (char *)arg);
1086 	case BLKTRACESTART:
1087 		return blk_trace_startstop(sdp->device->request_queue, 1);
1088 	case BLKTRACESTOP:
1089 		return blk_trace_startstop(sdp->device->request_queue, 0);
1090 	case BLKTRACETEARDOWN:
1091 		return blk_trace_remove(sdp->device->request_queue);
1092 	case SCSI_IOCTL_GET_IDLUN:
1093 	case SCSI_IOCTL_GET_BUS_NUMBER:
1094 	case SCSI_IOCTL_PROBE_HOST:
1095 	case SG_GET_TRANSFORM:
1096 	case SG_SCSI_RESET:
1097 		if (atomic_read(&sdp->detaching))
1098 			return -ENODEV;
1099 		break;
1100 	default:
1101 		if (read_only)
1102 			return -EPERM;	/* don't know so take safe approach */
1103 		break;
1104 	}
1105 
1106 	result = scsi_ioctl_block_when_processing_errors(sdp->device,
1107 			cmd_in, filp->f_flags & O_NDELAY);
1108 	if (result)
1109 		return result;
1110 	return scsi_ioctl(sdp->device, cmd_in, p);
1111 }
1112 
1113 #ifdef CONFIG_COMPAT
1114 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1115 {
1116 	Sg_device *sdp;
1117 	Sg_fd *sfp;
1118 	struct scsi_device *sdev;
1119 
1120 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1121 		return -ENXIO;
1122 
1123 	sdev = sdp->device;
1124 	if (sdev->host->hostt->compat_ioctl) {
1125 		int ret;
1126 
1127 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1128 
1129 		return ret;
1130 	}
1131 
1132 	return -ENOIOCTLCMD;
1133 }
1134 #endif
1135 
1136 static unsigned int
1137 sg_poll(struct file *filp, poll_table * wait)
1138 {
1139 	unsigned int res = 0;
1140 	Sg_device *sdp;
1141 	Sg_fd *sfp;
1142 	Sg_request *srp;
1143 	int count = 0;
1144 	unsigned long iflags;
1145 
1146 	sfp = filp->private_data;
1147 	if (!sfp)
1148 		return POLLERR;
1149 	sdp = sfp->parentdp;
1150 	if (!sdp)
1151 		return POLLERR;
1152 	poll_wait(filp, &sfp->read_wait, wait);
1153 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1154 	list_for_each_entry(srp, &sfp->rq_list, entry) {
1155 		/* if any read waiting, flag it */
1156 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1157 			res = POLLIN | POLLRDNORM;
1158 		++count;
1159 	}
1160 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1161 
1162 	if (atomic_read(&sdp->detaching))
1163 		res |= POLLHUP;
1164 	else if (!sfp->cmd_q) {
1165 		if (0 == count)
1166 			res |= POLLOUT | POLLWRNORM;
1167 	} else if (count < SG_MAX_QUEUE)
1168 		res |= POLLOUT | POLLWRNORM;
1169 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1170 				      "sg_poll: res=0x%x\n", (int) res));
1171 	return res;
1172 }
1173 
1174 static int
1175 sg_fasync(int fd, struct file *filp, int mode)
1176 {
1177 	Sg_device *sdp;
1178 	Sg_fd *sfp;
1179 
1180 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1181 		return -ENXIO;
1182 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1183 				      "sg_fasync: mode=%d\n", mode));
1184 
1185 	return fasync_helper(fd, filp, mode, &sfp->async_qp);
1186 }
1187 
1188 static int
1189 sg_vma_fault(struct vm_fault *vmf)
1190 {
1191 	struct vm_area_struct *vma = vmf->vma;
1192 	Sg_fd *sfp;
1193 	unsigned long offset, len, sa;
1194 	Sg_scatter_hold *rsv_schp;
1195 	int k, length;
1196 
1197 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1198 		return VM_FAULT_SIGBUS;
1199 	rsv_schp = &sfp->reserve;
1200 	offset = vmf->pgoff << PAGE_SHIFT;
1201 	if (offset >= rsv_schp->bufflen)
1202 		return VM_FAULT_SIGBUS;
1203 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1204 				      "sg_vma_fault: offset=%lu, scatg=%d\n",
1205 				      offset, rsv_schp->k_use_sg));
1206 	sa = vma->vm_start;
1207 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1208 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1209 		len = vma->vm_end - sa;
1210 		len = (len < length) ? len : length;
1211 		if (offset < len) {
1212 			struct page *page = nth_page(rsv_schp->pages[k],
1213 						     offset >> PAGE_SHIFT);
1214 			get_page(page);	/* increment page count */
1215 			vmf->page = page;
1216 			return 0; /* success */
1217 		}
1218 		sa += len;
1219 		offset -= len;
1220 	}
1221 
1222 	return VM_FAULT_SIGBUS;
1223 }
1224 
1225 static const struct vm_operations_struct sg_mmap_vm_ops = {
1226 	.fault = sg_vma_fault,
1227 };
1228 
1229 static int
1230 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1231 {
1232 	Sg_fd *sfp;
1233 	unsigned long req_sz, len, sa;
1234 	Sg_scatter_hold *rsv_schp;
1235 	int k, length;
1236 
1237 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1238 		return -ENXIO;
1239 	req_sz = vma->vm_end - vma->vm_start;
1240 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1241 				      "sg_mmap starting, vm_start=%p, len=%d\n",
1242 				      (void *) vma->vm_start, (int) req_sz));
1243 	if (vma->vm_pgoff)
1244 		return -EINVAL;	/* want no offset */
1245 	rsv_schp = &sfp->reserve;
1246 	if (req_sz > rsv_schp->bufflen)
1247 		return -ENOMEM;	/* cannot map more than reserved buffer */
1248 
1249 	sa = vma->vm_start;
1250 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1251 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1252 		len = vma->vm_end - sa;
1253 		len = (len < length) ? len : length;
1254 		sa += len;
1255 	}
1256 
1257 	sfp->mmap_called = 1;
1258 	vma->vm_flags |= VM_IO | VM_DONTEXPAND | VM_DONTDUMP;
1259 	vma->vm_private_data = sfp;
1260 	vma->vm_ops = &sg_mmap_vm_ops;
1261 	return 0;
1262 }
1263 
1264 static void
1265 sg_rq_end_io_usercontext(struct work_struct *work)
1266 {
1267 	struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1268 	struct sg_fd *sfp = srp->parentfp;
1269 
1270 	sg_finish_rem_req(srp);
1271 	sg_remove_request(sfp, srp);
1272 	kref_put(&sfp->f_ref, sg_remove_sfp);
1273 }
1274 
1275 /*
1276  * This function is a "bottom half" handler that is called by the mid
1277  * level when a command is completed (or has failed).
1278  */
1279 static void
1280 sg_rq_end_io(struct request *rq, blk_status_t status)
1281 {
1282 	struct sg_request *srp = rq->end_io_data;
1283 	struct scsi_request *req = scsi_req(rq);
1284 	Sg_device *sdp;
1285 	Sg_fd *sfp;
1286 	unsigned long iflags;
1287 	unsigned int ms;
1288 	char *sense;
1289 	int result, resid, done = 1;
1290 
1291 	if (WARN_ON(srp->done != 0))
1292 		return;
1293 
1294 	sfp = srp->parentfp;
1295 	if (WARN_ON(sfp == NULL))
1296 		return;
1297 
1298 	sdp = sfp->parentdp;
1299 	if (unlikely(atomic_read(&sdp->detaching)))
1300 		pr_info("%s: device detaching\n", __func__);
1301 
1302 	sense = req->sense;
1303 	result = req->result;
1304 	resid = req->resid_len;
1305 
1306 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
1307 				      "sg_cmd_done: pack_id=%d, res=0x%x\n",
1308 				      srp->header.pack_id, result));
1309 	srp->header.resid = resid;
1310 	ms = jiffies_to_msecs(jiffies);
1311 	srp->header.duration = (ms > srp->header.duration) ?
1312 				(ms - srp->header.duration) : 0;
1313 	if (0 != result) {
1314 		struct scsi_sense_hdr sshdr;
1315 
1316 		srp->header.status = 0xff & result;
1317 		srp->header.masked_status = status_byte(result);
1318 		srp->header.msg_status = msg_byte(result);
1319 		srp->header.host_status = host_byte(result);
1320 		srp->header.driver_status = driver_byte(result);
1321 		if ((sdp->sgdebug > 0) &&
1322 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1323 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1324 			__scsi_print_sense(sdp->device, __func__, sense,
1325 					   SCSI_SENSE_BUFFERSIZE);
1326 
1327 		/* Following if statement is a patch supplied by Eric Youngdale */
1328 		if (driver_byte(result) != 0
1329 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1330 		    && !scsi_sense_is_deferred(&sshdr)
1331 		    && sshdr.sense_key == UNIT_ATTENTION
1332 		    && sdp->device->removable) {
1333 			/* Detected possible disc change. Set the bit - this */
1334 			/* may be used if there are filesystems using this device */
1335 			sdp->device->changed = 1;
1336 		}
1337 	}
1338 
1339 	if (req->sense_len)
1340 		memcpy(srp->sense_b, req->sense, SCSI_SENSE_BUFFERSIZE);
1341 
1342 	/* Rely on write phase to clean out srp status values, so no "else" */
1343 
1344 	/*
1345 	 * Free the request as soon as it is complete so that its resources
1346 	 * can be reused without waiting for userspace to read() the
1347 	 * result.  But keep the associated bio (if any) around until
1348 	 * blk_rq_unmap_user() can be called from user context.
1349 	 */
1350 	srp->rq = NULL;
1351 	scsi_req_free_cmd(scsi_req(rq));
1352 	__blk_put_request(rq->q, rq);
1353 
1354 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1355 	if (unlikely(srp->orphan)) {
1356 		if (sfp->keep_orphan)
1357 			srp->sg_io_owned = 0;
1358 		else
1359 			done = 0;
1360 	}
1361 	srp->done = done;
1362 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1363 
1364 	if (likely(done)) {
1365 		/* Now wake up any sg_read() that is waiting for this
1366 		 * packet.
1367 		 */
1368 		wake_up_interruptible(&sfp->read_wait);
1369 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1370 		kref_put(&sfp->f_ref, sg_remove_sfp);
1371 	} else {
1372 		INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1373 		schedule_work(&srp->ew.work);
1374 	}
1375 }
1376 
1377 static const struct file_operations sg_fops = {
1378 	.owner = THIS_MODULE,
1379 	.read = sg_read,
1380 	.write = sg_write,
1381 	.poll = sg_poll,
1382 	.unlocked_ioctl = sg_ioctl,
1383 #ifdef CONFIG_COMPAT
1384 	.compat_ioctl = sg_compat_ioctl,
1385 #endif
1386 	.open = sg_open,
1387 	.mmap = sg_mmap,
1388 	.release = sg_release,
1389 	.fasync = sg_fasync,
1390 	.llseek = no_llseek,
1391 };
1392 
1393 static struct class *sg_sysfs_class;
1394 
1395 static int sg_sysfs_valid = 0;
1396 
1397 static Sg_device *
1398 sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1399 {
1400 	struct request_queue *q = scsidp->request_queue;
1401 	Sg_device *sdp;
1402 	unsigned long iflags;
1403 	int error;
1404 	u32 k;
1405 
1406 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1407 	if (!sdp) {
1408 		sdev_printk(KERN_WARNING, scsidp, "%s: kmalloc Sg_device "
1409 			    "failure\n", __func__);
1410 		return ERR_PTR(-ENOMEM);
1411 	}
1412 
1413 	idr_preload(GFP_KERNEL);
1414 	write_lock_irqsave(&sg_index_lock, iflags);
1415 
1416 	error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
1417 	if (error < 0) {
1418 		if (error == -ENOSPC) {
1419 			sdev_printk(KERN_WARNING, scsidp,
1420 				    "Unable to attach sg device type=%d, minor number exceeds %d\n",
1421 				    scsidp->type, SG_MAX_DEVS - 1);
1422 			error = -ENODEV;
1423 		} else {
1424 			sdev_printk(KERN_WARNING, scsidp, "%s: idr "
1425 				    "allocation Sg_device failure: %d\n",
1426 				    __func__, error);
1427 		}
1428 		goto out_unlock;
1429 	}
1430 	k = error;
1431 
1432 	SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, scsidp,
1433 					"sg_alloc: dev=%d \n", k));
1434 	sprintf(disk->disk_name, "sg%d", k);
1435 	disk->first_minor = k;
1436 	sdp->disk = disk;
1437 	sdp->device = scsidp;
1438 	mutex_init(&sdp->open_rel_lock);
1439 	INIT_LIST_HEAD(&sdp->sfds);
1440 	init_waitqueue_head(&sdp->open_wait);
1441 	atomic_set(&sdp->detaching, 0);
1442 	rwlock_init(&sdp->sfd_lock);
1443 	sdp->sg_tablesize = queue_max_segments(q);
1444 	sdp->index = k;
1445 	kref_init(&sdp->d_ref);
1446 	error = 0;
1447 
1448 out_unlock:
1449 	write_unlock_irqrestore(&sg_index_lock, iflags);
1450 	idr_preload_end();
1451 
1452 	if (error) {
1453 		kfree(sdp);
1454 		return ERR_PTR(error);
1455 	}
1456 	return sdp;
1457 }
1458 
1459 static int
1460 sg_add_device(struct device *cl_dev, struct class_interface *cl_intf)
1461 {
1462 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1463 	struct gendisk *disk;
1464 	Sg_device *sdp = NULL;
1465 	struct cdev * cdev = NULL;
1466 	int error;
1467 	unsigned long iflags;
1468 
1469 	disk = alloc_disk(1);
1470 	if (!disk) {
1471 		pr_warn("%s: alloc_disk failed\n", __func__);
1472 		return -ENOMEM;
1473 	}
1474 	disk->major = SCSI_GENERIC_MAJOR;
1475 
1476 	error = -ENOMEM;
1477 	cdev = cdev_alloc();
1478 	if (!cdev) {
1479 		pr_warn("%s: cdev_alloc failed\n", __func__);
1480 		goto out;
1481 	}
1482 	cdev->owner = THIS_MODULE;
1483 	cdev->ops = &sg_fops;
1484 
1485 	sdp = sg_alloc(disk, scsidp);
1486 	if (IS_ERR(sdp)) {
1487 		pr_warn("%s: sg_alloc failed\n", __func__);
1488 		error = PTR_ERR(sdp);
1489 		goto out;
1490 	}
1491 
1492 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1493 	if (error)
1494 		goto cdev_add_err;
1495 
1496 	sdp->cdev = cdev;
1497 	if (sg_sysfs_valid) {
1498 		struct device *sg_class_member;
1499 
1500 		sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1501 						MKDEV(SCSI_GENERIC_MAJOR,
1502 						      sdp->index),
1503 						sdp, "%s", disk->disk_name);
1504 		if (IS_ERR(sg_class_member)) {
1505 			pr_err("%s: device_create failed\n", __func__);
1506 			error = PTR_ERR(sg_class_member);
1507 			goto cdev_add_err;
1508 		}
1509 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1510 					  &sg_class_member->kobj, "generic");
1511 		if (error)
1512 			pr_err("%s: unable to make symlink 'generic' back "
1513 			       "to sg%d\n", __func__, sdp->index);
1514 	} else
1515 		pr_warn("%s: sg_sys Invalid\n", __func__);
1516 
1517 	sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d "
1518 		    "type %d\n", sdp->index, scsidp->type);
1519 
1520 	dev_set_drvdata(cl_dev, sdp);
1521 
1522 	return 0;
1523 
1524 cdev_add_err:
1525 	write_lock_irqsave(&sg_index_lock, iflags);
1526 	idr_remove(&sg_index_idr, sdp->index);
1527 	write_unlock_irqrestore(&sg_index_lock, iflags);
1528 	kfree(sdp);
1529 
1530 out:
1531 	put_disk(disk);
1532 	if (cdev)
1533 		cdev_del(cdev);
1534 	return error;
1535 }
1536 
1537 static void
1538 sg_device_destroy(struct kref *kref)
1539 {
1540 	struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1541 	unsigned long flags;
1542 
1543 	/* CAUTION!  Note that the device can still be found via idr_find()
1544 	 * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1545 	 * any other cleanup.
1546 	 */
1547 
1548 	write_lock_irqsave(&sg_index_lock, flags);
1549 	idr_remove(&sg_index_idr, sdp->index);
1550 	write_unlock_irqrestore(&sg_index_lock, flags);
1551 
1552 	SCSI_LOG_TIMEOUT(3,
1553 		sg_printk(KERN_INFO, sdp, "sg_device_destroy\n"));
1554 
1555 	put_disk(sdp->disk);
1556 	kfree(sdp);
1557 }
1558 
1559 static void
1560 sg_remove_device(struct device *cl_dev, struct class_interface *cl_intf)
1561 {
1562 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1563 	Sg_device *sdp = dev_get_drvdata(cl_dev);
1564 	unsigned long iflags;
1565 	Sg_fd *sfp;
1566 	int val;
1567 
1568 	if (!sdp)
1569 		return;
1570 	/* want sdp->detaching non-zero as soon as possible */
1571 	val = atomic_inc_return(&sdp->detaching);
1572 	if (val > 1)
1573 		return; /* only want to do following once per device */
1574 
1575 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1576 				      "%s\n", __func__));
1577 
1578 	read_lock_irqsave(&sdp->sfd_lock, iflags);
1579 	list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1580 		wake_up_interruptible_all(&sfp->read_wait);
1581 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1582 	}
1583 	wake_up_interruptible_all(&sdp->open_wait);
1584 	read_unlock_irqrestore(&sdp->sfd_lock, iflags);
1585 
1586 	sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1587 	device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1588 	cdev_del(sdp->cdev);
1589 	sdp->cdev = NULL;
1590 
1591 	kref_put(&sdp->d_ref, sg_device_destroy);
1592 }
1593 
1594 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1595 module_param_named(def_reserved_size, def_reserved_size, int,
1596 		   S_IRUGO | S_IWUSR);
1597 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1598 
1599 MODULE_AUTHOR("Douglas Gilbert");
1600 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1601 MODULE_LICENSE("GPL");
1602 MODULE_VERSION(SG_VERSION_STR);
1603 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1604 
1605 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1606                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1607 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1608 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1609 
1610 static int __init
1611 init_sg(void)
1612 {
1613 	int rc;
1614 
1615 	if (scatter_elem_sz < PAGE_SIZE) {
1616 		scatter_elem_sz = PAGE_SIZE;
1617 		scatter_elem_sz_prev = scatter_elem_sz;
1618 	}
1619 	if (def_reserved_size >= 0)
1620 		sg_big_buff = def_reserved_size;
1621 	else
1622 		def_reserved_size = sg_big_buff;
1623 
1624 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1625 				    SG_MAX_DEVS, "sg");
1626 	if (rc)
1627 		return rc;
1628         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1629         if ( IS_ERR(sg_sysfs_class) ) {
1630 		rc = PTR_ERR(sg_sysfs_class);
1631 		goto err_out;
1632         }
1633 	sg_sysfs_valid = 1;
1634 	rc = scsi_register_interface(&sg_interface);
1635 	if (0 == rc) {
1636 #ifdef CONFIG_SCSI_PROC_FS
1637 		sg_proc_init();
1638 #endif				/* CONFIG_SCSI_PROC_FS */
1639 		return 0;
1640 	}
1641 	class_destroy(sg_sysfs_class);
1642 err_out:
1643 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1644 	return rc;
1645 }
1646 
1647 static void __exit
1648 exit_sg(void)
1649 {
1650 #ifdef CONFIG_SCSI_PROC_FS
1651 	sg_proc_cleanup();
1652 #endif				/* CONFIG_SCSI_PROC_FS */
1653 	scsi_unregister_interface(&sg_interface);
1654 	class_destroy(sg_sysfs_class);
1655 	sg_sysfs_valid = 0;
1656 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1657 				 SG_MAX_DEVS);
1658 	idr_destroy(&sg_index_idr);
1659 }
1660 
1661 static int
1662 sg_start_req(Sg_request *srp, unsigned char *cmd)
1663 {
1664 	int res;
1665 	struct request *rq;
1666 	struct scsi_request *req;
1667 	Sg_fd *sfp = srp->parentfp;
1668 	sg_io_hdr_t *hp = &srp->header;
1669 	int dxfer_len = (int) hp->dxfer_len;
1670 	int dxfer_dir = hp->dxfer_direction;
1671 	unsigned int iov_count = hp->iovec_count;
1672 	Sg_scatter_hold *req_schp = &srp->data;
1673 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1674 	struct request_queue *q = sfp->parentdp->device->request_queue;
1675 	struct rq_map_data *md, map_data;
1676 	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1677 	unsigned char *long_cmdp = NULL;
1678 
1679 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1680 				      "sg_start_req: dxfer_len=%d\n",
1681 				      dxfer_len));
1682 
1683 	if (hp->cmd_len > BLK_MAX_CDB) {
1684 		long_cmdp = kzalloc(hp->cmd_len, GFP_KERNEL);
1685 		if (!long_cmdp)
1686 			return -ENOMEM;
1687 	}
1688 
1689 	/*
1690 	 * NOTE
1691 	 *
1692 	 * With scsi-mq enabled, there are a fixed number of preallocated
1693 	 * requests equal in number to shost->can_queue.  If all of the
1694 	 * preallocated requests are already in use, then using GFP_ATOMIC with
1695 	 * blk_get_request() will return -EWOULDBLOCK, whereas using GFP_KERNEL
1696 	 * will cause blk_get_request() to sleep until an active command
1697 	 * completes, freeing up a request.  Neither option is ideal, but
1698 	 * GFP_KERNEL is the better choice to prevent userspace from getting an
1699 	 * unexpected EWOULDBLOCK.
1700 	 *
1701 	 * With scsi-mq disabled, blk_get_request() with GFP_KERNEL usually
1702 	 * does not sleep except under memory pressure.
1703 	 */
1704 	rq = blk_get_request(q, hp->dxfer_direction == SG_DXFER_TO_DEV ?
1705 			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, GFP_KERNEL);
1706 	if (IS_ERR(rq)) {
1707 		kfree(long_cmdp);
1708 		return PTR_ERR(rq);
1709 	}
1710 	req = scsi_req(rq);
1711 
1712 	if (hp->cmd_len > BLK_MAX_CDB)
1713 		req->cmd = long_cmdp;
1714 	memcpy(req->cmd, cmd, hp->cmd_len);
1715 	req->cmd_len = hp->cmd_len;
1716 
1717 	srp->rq = rq;
1718 	rq->end_io_data = srp;
1719 	req->retries = SG_DEFAULT_RETRIES;
1720 
1721 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1722 		return 0;
1723 
1724 	if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1725 	    dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1726 	    !sfp->parentdp->device->host->unchecked_isa_dma &&
1727 	    blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1728 		md = NULL;
1729 	else
1730 		md = &map_data;
1731 
1732 	if (md) {
1733 		mutex_lock(&sfp->f_mutex);
1734 		if (dxfer_len <= rsv_schp->bufflen &&
1735 		    !sfp->res_in_use) {
1736 			sfp->res_in_use = 1;
1737 			sg_link_reserve(sfp, srp, dxfer_len);
1738 		} else if ((hp->flags & SG_FLAG_MMAP_IO) && sfp->res_in_use) {
1739 			mutex_unlock(&sfp->f_mutex);
1740 			return -EBUSY;
1741 		} else {
1742 			res = sg_build_indirect(req_schp, sfp, dxfer_len);
1743 			if (res) {
1744 				mutex_unlock(&sfp->f_mutex);
1745 				return res;
1746 			}
1747 		}
1748 		mutex_unlock(&sfp->f_mutex);
1749 
1750 		md->pages = req_schp->pages;
1751 		md->page_order = req_schp->page_order;
1752 		md->nr_entries = req_schp->k_use_sg;
1753 		md->offset = 0;
1754 		md->null_mapped = hp->dxferp ? 0 : 1;
1755 		if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1756 			md->from_user = 1;
1757 		else
1758 			md->from_user = 0;
1759 	}
1760 
1761 	if (iov_count) {
1762 		struct iovec *iov = NULL;
1763 		struct iov_iter i;
1764 
1765 		res = import_iovec(rw, hp->dxferp, iov_count, 0, &iov, &i);
1766 		if (res < 0)
1767 			return res;
1768 
1769 		iov_iter_truncate(&i, hp->dxfer_len);
1770 		if (!iov_iter_count(&i)) {
1771 			kfree(iov);
1772 			return -EINVAL;
1773 		}
1774 
1775 		res = blk_rq_map_user_iov(q, rq, md, &i, GFP_ATOMIC);
1776 		kfree(iov);
1777 	} else
1778 		res = blk_rq_map_user(q, rq, md, hp->dxferp,
1779 				      hp->dxfer_len, GFP_ATOMIC);
1780 
1781 	if (!res) {
1782 		srp->bio = rq->bio;
1783 
1784 		if (!md) {
1785 			req_schp->dio_in_use = 1;
1786 			hp->info |= SG_INFO_DIRECT_IO;
1787 		}
1788 	}
1789 	return res;
1790 }
1791 
1792 static int
1793 sg_finish_rem_req(Sg_request *srp)
1794 {
1795 	int ret = 0;
1796 
1797 	Sg_fd *sfp = srp->parentfp;
1798 	Sg_scatter_hold *req_schp = &srp->data;
1799 
1800 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1801 				      "sg_finish_rem_req: res_used=%d\n",
1802 				      (int) srp->res_used));
1803 	if (srp->bio)
1804 		ret = blk_rq_unmap_user(srp->bio);
1805 
1806 	if (srp->rq) {
1807 		scsi_req_free_cmd(scsi_req(srp->rq));
1808 		blk_put_request(srp->rq);
1809 	}
1810 
1811 	if (srp->res_used)
1812 		sg_unlink_reserve(sfp, srp);
1813 	else
1814 		sg_remove_scat(sfp, req_schp);
1815 
1816 	return ret;
1817 }
1818 
1819 static int
1820 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1821 {
1822 	int sg_bufflen = tablesize * sizeof(struct page *);
1823 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1824 
1825 	schp->pages = kzalloc(sg_bufflen, gfp_flags);
1826 	if (!schp->pages)
1827 		return -ENOMEM;
1828 	schp->sglist_len = sg_bufflen;
1829 	return tablesize;	/* number of scat_gath elements allocated */
1830 }
1831 
1832 static int
1833 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1834 {
1835 	int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1836 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1837 	int blk_size = buff_size, order;
1838 	gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
1839 	struct sg_device *sdp = sfp->parentdp;
1840 
1841 	if (blk_size < 0)
1842 		return -EFAULT;
1843 	if (0 == blk_size)
1844 		++blk_size;	/* don't know why */
1845 	/* round request up to next highest SG_SECTOR_SZ byte boundary */
1846 	blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1847 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1848 		"sg_build_indirect: buff_size=%d, blk_size=%d\n",
1849 		buff_size, blk_size));
1850 
1851 	/* N.B. ret_sz carried into this block ... */
1852 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1853 	if (mx_sc_elems < 0)
1854 		return mx_sc_elems;	/* most likely -ENOMEM */
1855 
1856 	num = scatter_elem_sz;
1857 	if (unlikely(num != scatter_elem_sz_prev)) {
1858 		if (num < PAGE_SIZE) {
1859 			scatter_elem_sz = PAGE_SIZE;
1860 			scatter_elem_sz_prev = PAGE_SIZE;
1861 		} else
1862 			scatter_elem_sz_prev = num;
1863 	}
1864 
1865 	if (sdp->device->host->unchecked_isa_dma)
1866 		gfp_mask |= GFP_DMA;
1867 
1868 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1869 		gfp_mask |= __GFP_ZERO;
1870 
1871 	order = get_order(num);
1872 retry:
1873 	ret_sz = 1 << (PAGE_SHIFT + order);
1874 
1875 	for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1876 	     k++, rem_sz -= ret_sz) {
1877 
1878 		num = (rem_sz > scatter_elem_sz_prev) ?
1879 			scatter_elem_sz_prev : rem_sz;
1880 
1881 		schp->pages[k] = alloc_pages(gfp_mask, order);
1882 		if (!schp->pages[k])
1883 			goto out;
1884 
1885 		if (num == scatter_elem_sz_prev) {
1886 			if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1887 				scatter_elem_sz = ret_sz;
1888 				scatter_elem_sz_prev = ret_sz;
1889 			}
1890 		}
1891 
1892 		SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1893 				 "sg_build_indirect: k=%d, num=%d, ret_sz=%d\n",
1894 				 k, num, ret_sz));
1895 	}		/* end of for loop */
1896 
1897 	schp->page_order = order;
1898 	schp->k_use_sg = k;
1899 	SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1900 			 "sg_build_indirect: k_use_sg=%d, rem_sz=%d\n",
1901 			 k, rem_sz));
1902 
1903 	schp->bufflen = blk_size;
1904 	if (rem_sz > 0)	/* must have failed */
1905 		return -ENOMEM;
1906 	return 0;
1907 out:
1908 	for (i = 0; i < k; i++)
1909 		__free_pages(schp->pages[i], order);
1910 
1911 	if (--order >= 0)
1912 		goto retry;
1913 
1914 	return -ENOMEM;
1915 }
1916 
1917 static void
1918 sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp)
1919 {
1920 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1921 			 "sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1922 	if (schp->pages && schp->sglist_len > 0) {
1923 		if (!schp->dio_in_use) {
1924 			int k;
1925 
1926 			for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1927 				SCSI_LOG_TIMEOUT(5,
1928 					sg_printk(KERN_INFO, sfp->parentdp,
1929 					"sg_remove_scat: k=%d, pg=0x%p\n",
1930 					k, schp->pages[k]));
1931 				__free_pages(schp->pages[k], schp->page_order);
1932 			}
1933 
1934 			kfree(schp->pages);
1935 		}
1936 	}
1937 	memset(schp, 0, sizeof (*schp));
1938 }
1939 
1940 static int
1941 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1942 {
1943 	Sg_scatter_hold *schp = &srp->data;
1944 	int k, num;
1945 
1946 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
1947 			 "sg_read_oxfer: num_read_xfer=%d\n",
1948 			 num_read_xfer));
1949 	if ((!outp) || (num_read_xfer <= 0))
1950 		return 0;
1951 
1952 	num = 1 << (PAGE_SHIFT + schp->page_order);
1953 	for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1954 		if (num > num_read_xfer) {
1955 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1956 					   num_read_xfer))
1957 				return -EFAULT;
1958 			break;
1959 		} else {
1960 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1961 					   num))
1962 				return -EFAULT;
1963 			num_read_xfer -= num;
1964 			if (num_read_xfer <= 0)
1965 				break;
1966 			outp += num;
1967 		}
1968 	}
1969 
1970 	return 0;
1971 }
1972 
1973 static void
1974 sg_build_reserve(Sg_fd * sfp, int req_size)
1975 {
1976 	Sg_scatter_hold *schp = &sfp->reserve;
1977 
1978 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1979 			 "sg_build_reserve: req_size=%d\n", req_size));
1980 	do {
1981 		if (req_size < PAGE_SIZE)
1982 			req_size = PAGE_SIZE;
1983 		if (0 == sg_build_indirect(schp, sfp, req_size))
1984 			return;
1985 		else
1986 			sg_remove_scat(sfp, schp);
1987 		req_size >>= 1;	/* divide by 2 */
1988 	} while (req_size > (PAGE_SIZE / 2));
1989 }
1990 
1991 static void
1992 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
1993 {
1994 	Sg_scatter_hold *req_schp = &srp->data;
1995 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1996 	int k, num, rem;
1997 
1998 	srp->res_used = 1;
1999 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2000 			 "sg_link_reserve: size=%d\n", size));
2001 	rem = size;
2002 
2003 	num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
2004 	for (k = 0; k < rsv_schp->k_use_sg; k++) {
2005 		if (rem <= num) {
2006 			req_schp->k_use_sg = k + 1;
2007 			req_schp->sglist_len = rsv_schp->sglist_len;
2008 			req_schp->pages = rsv_schp->pages;
2009 
2010 			req_schp->bufflen = size;
2011 			req_schp->page_order = rsv_schp->page_order;
2012 			break;
2013 		} else
2014 			rem -= num;
2015 	}
2016 
2017 	if (k >= rsv_schp->k_use_sg)
2018 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
2019 				 "sg_link_reserve: BAD size\n"));
2020 }
2021 
2022 static void
2023 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2024 {
2025 	Sg_scatter_hold *req_schp = &srp->data;
2026 
2027 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
2028 				      "sg_unlink_reserve: req->k_use_sg=%d\n",
2029 				      (int) req_schp->k_use_sg));
2030 	req_schp->k_use_sg = 0;
2031 	req_schp->bufflen = 0;
2032 	req_schp->pages = NULL;
2033 	req_schp->page_order = 0;
2034 	req_schp->sglist_len = 0;
2035 	srp->res_used = 0;
2036 	/* Called without mutex lock to avoid deadlock */
2037 	sfp->res_in_use = 0;
2038 }
2039 
2040 static Sg_request *
2041 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
2042 {
2043 	Sg_request *resp;
2044 	unsigned long iflags;
2045 
2046 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2047 	list_for_each_entry(resp, &sfp->rq_list, entry) {
2048 		/* look for requests that are ready + not SG_IO owned */
2049 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
2050 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2051 			resp->done = 2;	/* guard against other readers */
2052 			write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2053 			return resp;
2054 		}
2055 	}
2056 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2057 	return NULL;
2058 }
2059 
2060 /* always adds to end of list */
2061 static Sg_request *
2062 sg_add_request(Sg_fd * sfp)
2063 {
2064 	int k;
2065 	unsigned long iflags;
2066 	Sg_request *rp = sfp->req_arr;
2067 
2068 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2069 	if (!list_empty(&sfp->rq_list)) {
2070 		if (!sfp->cmd_q)
2071 			goto out_unlock;
2072 
2073 		for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2074 			if (!rp->parentfp)
2075 				break;
2076 		}
2077 		if (k >= SG_MAX_QUEUE)
2078 			goto out_unlock;
2079 	}
2080 	memset(rp, 0, sizeof (Sg_request));
2081 	rp->parentfp = sfp;
2082 	rp->header.duration = jiffies_to_msecs(jiffies);
2083 	list_add_tail(&rp->entry, &sfp->rq_list);
2084 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2085 	return rp;
2086 out_unlock:
2087 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2088 	return NULL;
2089 }
2090 
2091 /* Return of 1 for found; 0 for not found */
2092 static int
2093 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2094 {
2095 	unsigned long iflags;
2096 	int res = 0;
2097 
2098 	if (!sfp || !srp || list_empty(&sfp->rq_list))
2099 		return res;
2100 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2101 	if (!list_empty(&srp->entry)) {
2102 		list_del(&srp->entry);
2103 		srp->parentfp = NULL;
2104 		res = 1;
2105 	}
2106 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2107 	return res;
2108 }
2109 
2110 static Sg_fd *
2111 sg_add_sfp(Sg_device * sdp)
2112 {
2113 	Sg_fd *sfp;
2114 	unsigned long iflags;
2115 	int bufflen;
2116 
2117 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2118 	if (!sfp)
2119 		return ERR_PTR(-ENOMEM);
2120 
2121 	init_waitqueue_head(&sfp->read_wait);
2122 	rwlock_init(&sfp->rq_list_lock);
2123 	INIT_LIST_HEAD(&sfp->rq_list);
2124 	kref_init(&sfp->f_ref);
2125 	mutex_init(&sfp->f_mutex);
2126 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2127 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2128 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2129 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2130 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2131 	sfp->parentdp = sdp;
2132 	write_lock_irqsave(&sdp->sfd_lock, iflags);
2133 	if (atomic_read(&sdp->detaching)) {
2134 		write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2135 		return ERR_PTR(-ENODEV);
2136 	}
2137 	list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2138 	write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2139 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2140 				      "sg_add_sfp: sfp=0x%p\n", sfp));
2141 	if (unlikely(sg_big_buff != def_reserved_size))
2142 		sg_big_buff = def_reserved_size;
2143 
2144 	bufflen = min_t(int, sg_big_buff,
2145 			max_sectors_bytes(sdp->device->request_queue));
2146 	sg_build_reserve(sfp, bufflen);
2147 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2148 				      "sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
2149 				      sfp->reserve.bufflen,
2150 				      sfp->reserve.k_use_sg));
2151 
2152 	kref_get(&sdp->d_ref);
2153 	__module_get(THIS_MODULE);
2154 	return sfp;
2155 }
2156 
2157 static void
2158 sg_remove_sfp_usercontext(struct work_struct *work)
2159 {
2160 	struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2161 	struct sg_device *sdp = sfp->parentdp;
2162 	Sg_request *srp;
2163 	unsigned long iflags;
2164 
2165 	/* Cleanup any responses which were never read(). */
2166 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2167 	while (!list_empty(&sfp->rq_list)) {
2168 		srp = list_first_entry(&sfp->rq_list, Sg_request, entry);
2169 		sg_finish_rem_req(srp);
2170 		list_del(&srp->entry);
2171 		srp->parentfp = NULL;
2172 	}
2173 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2174 
2175 	if (sfp->reserve.bufflen > 0) {
2176 		SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2177 				"sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2178 				(int) sfp->reserve.bufflen,
2179 				(int) sfp->reserve.k_use_sg));
2180 		sg_remove_scat(sfp, &sfp->reserve);
2181 	}
2182 
2183 	SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2184 			"sg_remove_sfp: sfp=0x%p\n", sfp));
2185 	kfree(sfp);
2186 
2187 	scsi_device_put(sdp->device);
2188 	kref_put(&sdp->d_ref, sg_device_destroy);
2189 	module_put(THIS_MODULE);
2190 }
2191 
2192 static void
2193 sg_remove_sfp(struct kref *kref)
2194 {
2195 	struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2196 	struct sg_device *sdp = sfp->parentdp;
2197 	unsigned long iflags;
2198 
2199 	write_lock_irqsave(&sdp->sfd_lock, iflags);
2200 	list_del(&sfp->sfd_siblings);
2201 	write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2202 
2203 	INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2204 	schedule_work(&sfp->ew.work);
2205 }
2206 
2207 #ifdef CONFIG_SCSI_PROC_FS
2208 static int
2209 sg_idr_max_id(int id, void *p, void *data)
2210 {
2211 	int *k = data;
2212 
2213 	if (*k < id)
2214 		*k = id;
2215 
2216 	return 0;
2217 }
2218 
2219 static int
2220 sg_last_dev(void)
2221 {
2222 	int k = -1;
2223 	unsigned long iflags;
2224 
2225 	read_lock_irqsave(&sg_index_lock, iflags);
2226 	idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2227 	read_unlock_irqrestore(&sg_index_lock, iflags);
2228 	return k + 1;		/* origin 1 */
2229 }
2230 #endif
2231 
2232 /* must be called with sg_index_lock held */
2233 static Sg_device *sg_lookup_dev(int dev)
2234 {
2235 	return idr_find(&sg_index_idr, dev);
2236 }
2237 
2238 static Sg_device *
2239 sg_get_dev(int dev)
2240 {
2241 	struct sg_device *sdp;
2242 	unsigned long flags;
2243 
2244 	read_lock_irqsave(&sg_index_lock, flags);
2245 	sdp = sg_lookup_dev(dev);
2246 	if (!sdp)
2247 		sdp = ERR_PTR(-ENXIO);
2248 	else if (atomic_read(&sdp->detaching)) {
2249 		/* If sdp->detaching, then the refcount may already be 0, in
2250 		 * which case it would be a bug to do kref_get().
2251 		 */
2252 		sdp = ERR_PTR(-ENODEV);
2253 	} else
2254 		kref_get(&sdp->d_ref);
2255 	read_unlock_irqrestore(&sg_index_lock, flags);
2256 
2257 	return sdp;
2258 }
2259 
2260 #ifdef CONFIG_SCSI_PROC_FS
2261 
2262 static struct proc_dir_entry *sg_proc_sgp = NULL;
2263 
2264 static char sg_proc_sg_dirname[] = "scsi/sg";
2265 
2266 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2267 
2268 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2269 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2270 			          size_t count, loff_t *off);
2271 static const struct file_operations adio_fops = {
2272 	.owner = THIS_MODULE,
2273 	.open = sg_proc_single_open_adio,
2274 	.read = seq_read,
2275 	.llseek = seq_lseek,
2276 	.write = sg_proc_write_adio,
2277 	.release = single_release,
2278 };
2279 
2280 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2281 static ssize_t sg_proc_write_dressz(struct file *filp,
2282 		const char __user *buffer, size_t count, loff_t *off);
2283 static const struct file_operations dressz_fops = {
2284 	.owner = THIS_MODULE,
2285 	.open = sg_proc_single_open_dressz,
2286 	.read = seq_read,
2287 	.llseek = seq_lseek,
2288 	.write = sg_proc_write_dressz,
2289 	.release = single_release,
2290 };
2291 
2292 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2293 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2294 static const struct file_operations version_fops = {
2295 	.owner = THIS_MODULE,
2296 	.open = sg_proc_single_open_version,
2297 	.read = seq_read,
2298 	.llseek = seq_lseek,
2299 	.release = single_release,
2300 };
2301 
2302 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2303 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2304 static const struct file_operations devhdr_fops = {
2305 	.owner = THIS_MODULE,
2306 	.open = sg_proc_single_open_devhdr,
2307 	.read = seq_read,
2308 	.llseek = seq_lseek,
2309 	.release = single_release,
2310 };
2311 
2312 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2313 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2314 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2315 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2316 static void dev_seq_stop(struct seq_file *s, void *v);
2317 static const struct file_operations dev_fops = {
2318 	.owner = THIS_MODULE,
2319 	.open = sg_proc_open_dev,
2320 	.read = seq_read,
2321 	.llseek = seq_lseek,
2322 	.release = seq_release,
2323 };
2324 static const struct seq_operations dev_seq_ops = {
2325 	.start = dev_seq_start,
2326 	.next  = dev_seq_next,
2327 	.stop  = dev_seq_stop,
2328 	.show  = sg_proc_seq_show_dev,
2329 };
2330 
2331 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2332 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2333 static const struct file_operations devstrs_fops = {
2334 	.owner = THIS_MODULE,
2335 	.open = sg_proc_open_devstrs,
2336 	.read = seq_read,
2337 	.llseek = seq_lseek,
2338 	.release = seq_release,
2339 };
2340 static const struct seq_operations devstrs_seq_ops = {
2341 	.start = dev_seq_start,
2342 	.next  = dev_seq_next,
2343 	.stop  = dev_seq_stop,
2344 	.show  = sg_proc_seq_show_devstrs,
2345 };
2346 
2347 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2348 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2349 static const struct file_operations debug_fops = {
2350 	.owner = THIS_MODULE,
2351 	.open = sg_proc_open_debug,
2352 	.read = seq_read,
2353 	.llseek = seq_lseek,
2354 	.release = seq_release,
2355 };
2356 static const struct seq_operations debug_seq_ops = {
2357 	.start = dev_seq_start,
2358 	.next  = dev_seq_next,
2359 	.stop  = dev_seq_stop,
2360 	.show  = sg_proc_seq_show_debug,
2361 };
2362 
2363 
2364 struct sg_proc_leaf {
2365 	const char * name;
2366 	const struct file_operations * fops;
2367 };
2368 
2369 static const struct sg_proc_leaf sg_proc_leaf_arr[] = {
2370 	{"allow_dio", &adio_fops},
2371 	{"debug", &debug_fops},
2372 	{"def_reserved_size", &dressz_fops},
2373 	{"device_hdr", &devhdr_fops},
2374 	{"devices", &dev_fops},
2375 	{"device_strs", &devstrs_fops},
2376 	{"version", &version_fops}
2377 };
2378 
2379 static int
2380 sg_proc_init(void)
2381 {
2382 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2383 	int k;
2384 
2385 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2386 	if (!sg_proc_sgp)
2387 		return 1;
2388 	for (k = 0; k < num_leaves; ++k) {
2389 		const struct sg_proc_leaf *leaf = &sg_proc_leaf_arr[k];
2390 		umode_t mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2391 		proc_create(leaf->name, mask, sg_proc_sgp, leaf->fops);
2392 	}
2393 	return 0;
2394 }
2395 
2396 static void
2397 sg_proc_cleanup(void)
2398 {
2399 	int k;
2400 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2401 
2402 	if (!sg_proc_sgp)
2403 		return;
2404 	for (k = 0; k < num_leaves; ++k)
2405 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2406 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2407 }
2408 
2409 
2410 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2411 {
2412 	seq_printf(s, "%d\n", *((int *)s->private));
2413 	return 0;
2414 }
2415 
2416 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2417 {
2418 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2419 }
2420 
2421 static ssize_t
2422 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2423 		   size_t count, loff_t *off)
2424 {
2425 	int err;
2426 	unsigned long num;
2427 
2428 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2429 		return -EACCES;
2430 	err = kstrtoul_from_user(buffer, count, 0, &num);
2431 	if (err)
2432 		return err;
2433 	sg_allow_dio = num ? 1 : 0;
2434 	return count;
2435 }
2436 
2437 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2438 {
2439 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2440 }
2441 
2442 static ssize_t
2443 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2444 		     size_t count, loff_t *off)
2445 {
2446 	int err;
2447 	unsigned long k = ULONG_MAX;
2448 
2449 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2450 		return -EACCES;
2451 
2452 	err = kstrtoul_from_user(buffer, count, 0, &k);
2453 	if (err)
2454 		return err;
2455 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2456 		sg_big_buff = k;
2457 		return count;
2458 	}
2459 	return -ERANGE;
2460 }
2461 
2462 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2463 {
2464 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2465 		   sg_version_date);
2466 	return 0;
2467 }
2468 
2469 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2470 {
2471 	return single_open(file, sg_proc_seq_show_version, NULL);
2472 }
2473 
2474 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2475 {
2476 	seq_puts(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\tonline\n");
2477 	return 0;
2478 }
2479 
2480 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2481 {
2482 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2483 }
2484 
2485 struct sg_proc_deviter {
2486 	loff_t	index;
2487 	size_t	max;
2488 };
2489 
2490 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2491 {
2492 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2493 
2494 	s->private = it;
2495 	if (! it)
2496 		return NULL;
2497 
2498 	it->index = *pos;
2499 	it->max = sg_last_dev();
2500 	if (it->index >= it->max)
2501 		return NULL;
2502 	return it;
2503 }
2504 
2505 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2506 {
2507 	struct sg_proc_deviter * it = s->private;
2508 
2509 	*pos = ++it->index;
2510 	return (it->index < it->max) ? it : NULL;
2511 }
2512 
2513 static void dev_seq_stop(struct seq_file *s, void *v)
2514 {
2515 	kfree(s->private);
2516 }
2517 
2518 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2519 {
2520         return seq_open(file, &dev_seq_ops);
2521 }
2522 
2523 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2524 {
2525 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2526 	Sg_device *sdp;
2527 	struct scsi_device *scsidp;
2528 	unsigned long iflags;
2529 
2530 	read_lock_irqsave(&sg_index_lock, iflags);
2531 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2532 	if ((NULL == sdp) || (NULL == sdp->device) ||
2533 	    (atomic_read(&sdp->detaching)))
2534 		seq_puts(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2535 	else {
2536 		scsidp = sdp->device;
2537 		seq_printf(s, "%d\t%d\t%d\t%llu\t%d\t%d\t%d\t%d\t%d\n",
2538 			      scsidp->host->host_no, scsidp->channel,
2539 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2540 			      1,
2541 			      (int) scsidp->queue_depth,
2542 			      (int) atomic_read(&scsidp->device_busy),
2543 			      (int) scsi_device_online(scsidp));
2544 	}
2545 	read_unlock_irqrestore(&sg_index_lock, iflags);
2546 	return 0;
2547 }
2548 
2549 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2550 {
2551         return seq_open(file, &devstrs_seq_ops);
2552 }
2553 
2554 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2555 {
2556 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2557 	Sg_device *sdp;
2558 	struct scsi_device *scsidp;
2559 	unsigned long iflags;
2560 
2561 	read_lock_irqsave(&sg_index_lock, iflags);
2562 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2563 	scsidp = sdp ? sdp->device : NULL;
2564 	if (sdp && scsidp && (!atomic_read(&sdp->detaching)))
2565 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2566 			   scsidp->vendor, scsidp->model, scsidp->rev);
2567 	else
2568 		seq_puts(s, "<no active device>\n");
2569 	read_unlock_irqrestore(&sg_index_lock, iflags);
2570 	return 0;
2571 }
2572 
2573 /* must be called while holding sg_index_lock */
2574 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2575 {
2576 	int k, new_interface, blen, usg;
2577 	Sg_request *srp;
2578 	Sg_fd *fp;
2579 	const sg_io_hdr_t *hp;
2580 	const char * cp;
2581 	unsigned int ms;
2582 
2583 	k = 0;
2584 	list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2585 		k++;
2586 		read_lock(&fp->rq_list_lock); /* irqs already disabled */
2587 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2588 			   "(res)sgat=%d low_dma=%d\n", k,
2589 			   jiffies_to_msecs(fp->timeout),
2590 			   fp->reserve.bufflen,
2591 			   (int) fp->reserve.k_use_sg,
2592 			   (int) sdp->device->host->unchecked_isa_dma);
2593 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
2594 			   (int) fp->cmd_q, (int) fp->force_packid,
2595 			   (int) fp->keep_orphan);
2596 		list_for_each_entry(srp, &fp->rq_list, entry) {
2597 			hp = &srp->header;
2598 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2599 			if (srp->res_used) {
2600 				if (new_interface &&
2601 				    (SG_FLAG_MMAP_IO & hp->flags))
2602 					cp = "     mmap>> ";
2603 				else
2604 					cp = "     rb>> ";
2605 			} else {
2606 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2607 					cp = "     dio>> ";
2608 				else
2609 					cp = "     ";
2610 			}
2611 			seq_puts(s, cp);
2612 			blen = srp->data.bufflen;
2613 			usg = srp->data.k_use_sg;
2614 			seq_puts(s, srp->done ?
2615 				 ((1 == srp->done) ?  "rcv:" : "fin:")
2616 				  : "act:");
2617 			seq_printf(s, " id=%d blen=%d",
2618 				   srp->header.pack_id, blen);
2619 			if (srp->done)
2620 				seq_printf(s, " dur=%d", hp->duration);
2621 			else {
2622 				ms = jiffies_to_msecs(jiffies);
2623 				seq_printf(s, " t_o/elap=%d/%d",
2624 					(new_interface ? hp->timeout :
2625 						  jiffies_to_msecs(fp->timeout)),
2626 					(ms > hp->duration ? ms - hp->duration : 0));
2627 			}
2628 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2629 				   (int) srp->data.cmd_opcode);
2630 		}
2631 		if (list_empty(&fp->rq_list))
2632 			seq_puts(s, "     No requests active\n");
2633 		read_unlock(&fp->rq_list_lock);
2634 	}
2635 }
2636 
2637 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2638 {
2639         return seq_open(file, &debug_seq_ops);
2640 }
2641 
2642 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2643 {
2644 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2645 	Sg_device *sdp;
2646 	unsigned long iflags;
2647 
2648 	if (it && (0 == it->index))
2649 		seq_printf(s, "max_active_device=%d  def_reserved_size=%d\n",
2650 			   (int)it->max, sg_big_buff);
2651 
2652 	read_lock_irqsave(&sg_index_lock, iflags);
2653 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2654 	if (NULL == sdp)
2655 		goto skip;
2656 	read_lock(&sdp->sfd_lock);
2657 	if (!list_empty(&sdp->sfds)) {
2658 		seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2659 		if (atomic_read(&sdp->detaching))
2660 			seq_puts(s, "detaching pending close ");
2661 		else if (sdp->device) {
2662 			struct scsi_device *scsidp = sdp->device;
2663 
2664 			seq_printf(s, "%d:%d:%d:%llu   em=%d",
2665 				   scsidp->host->host_no,
2666 				   scsidp->channel, scsidp->id,
2667 				   scsidp->lun,
2668 				   scsidp->host->hostt->emulated);
2669 		}
2670 		seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
2671 			   sdp->sg_tablesize, sdp->exclude, sdp->open_cnt);
2672 		sg_proc_debug_helper(s, sdp);
2673 	}
2674 	read_unlock(&sdp->sfd_lock);
2675 skip:
2676 	read_unlock_irqrestore(&sg_index_lock, iflags);
2677 	return 0;
2678 }
2679 
2680 #endif				/* CONFIG_SCSI_PROC_FS */
2681 
2682 module_init(init_sg);
2683 module_exit(exit_sg);
2684