xref: /openbmc/linux/drivers/scsi/sg.c (revision 278002edb19bce2c628fafb0af936e77000f3a5b)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  History:
4  *  Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
5  *           to allow user process control of SCSI devices.
6  *  Development Sponsored by Killy Corp. NY NY
7  *
8  * Original driver (sg.c):
9  *        Copyright (C) 1992 Lawrence Foard
10  * Version 2 and 3 extensions to driver:
11  *        Copyright (C) 1998 - 2014 Douglas Gilbert
12  */
13 
14 static int sg_version_num = 30536;	/* 2 digits for each component */
15 #define SG_VERSION_STR "3.5.36"
16 
17 /*
18  *  D. P. Gilbert (dgilbert@interlog.com), notes:
19  *      - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
20  *        the kernel/module needs to be built with CONFIG_SCSI_LOGGING
21  *        (otherwise the macros compile to empty statements).
22  *
23  */
24 #include <linux/module.h>
25 
26 #include <linux/fs.h>
27 #include <linux/kernel.h>
28 #include <linux/sched.h>
29 #include <linux/string.h>
30 #include <linux/mm.h>
31 #include <linux/errno.h>
32 #include <linux/mtio.h>
33 #include <linux/ioctl.h>
34 #include <linux/major.h>
35 #include <linux/slab.h>
36 #include <linux/fcntl.h>
37 #include <linux/init.h>
38 #include <linux/poll.h>
39 #include <linux/moduleparam.h>
40 #include <linux/cdev.h>
41 #include <linux/idr.h>
42 #include <linux/seq_file.h>
43 #include <linux/blkdev.h>
44 #include <linux/delay.h>
45 #include <linux/blktrace_api.h>
46 #include <linux/mutex.h>
47 #include <linux/atomic.h>
48 #include <linux/ratelimit.h>
49 #include <linux/uio.h>
50 #include <linux/cred.h> /* for sg_check_file_access() */
51 
52 #include <scsi/scsi.h>
53 #include <scsi/scsi_cmnd.h>
54 #include <scsi/scsi_dbg.h>
55 #include <scsi/scsi_device.h>
56 #include <scsi/scsi_driver.h>
57 #include <scsi/scsi_eh.h>
58 #include <scsi/scsi_host.h>
59 #include <scsi/scsi_ioctl.h>
60 #include <scsi/scsi_tcq.h>
61 #include <scsi/sg.h>
62 
63 #include "scsi_logging.h"
64 
65 #ifdef CONFIG_SCSI_PROC_FS
66 #include <linux/proc_fs.h>
67 static char *sg_version_date = "20140603";
68 
69 static int sg_proc_init(void);
70 #endif
71 
72 #define SG_ALLOW_DIO_DEF 0
73 
74 #define SG_MAX_DEVS (1 << MINORBITS)
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 static 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 *);
100 static void sg_remove_device(struct device *);
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 	char name[DISK_NAME_LEN];
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 enum rq_end_io_ret 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, bool *busy);
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, (sdp)->name, fmt, ##a)
211 
212 /*
213  * The SCSI interfaces that use read() and write() as an asynchronous variant of
214  * ioctl(..., SG_IO, ...) are fundamentally unsafe, since there are lots of ways
215  * to trigger read() and write() calls from various contexts with elevated
216  * privileges. This can lead to kernel memory corruption (e.g. if these
217  * interfaces are called through splice()) and privilege escalation inside
218  * userspace (e.g. if a process with access to such a device passes a file
219  * descriptor to a SUID binary as stdin/stdout/stderr).
220  *
221  * This function provides protection for the legacy API by restricting the
222  * calling context.
223  */
sg_check_file_access(struct file * filp,const char * caller)224 static int sg_check_file_access(struct file *filp, const char *caller)
225 {
226 	if (filp->f_cred != current_real_cred()) {
227 		pr_err_once("%s: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
228 			caller, task_tgid_vnr(current), current->comm);
229 		return -EPERM;
230 	}
231 	return 0;
232 }
233 
sg_allow_access(struct file * filp,unsigned char * cmd)234 static int sg_allow_access(struct file *filp, unsigned char *cmd)
235 {
236 	struct sg_fd *sfp = filp->private_data;
237 
238 	if (sfp->parentdp->device->type == TYPE_SCANNER)
239 		return 0;
240 	if (!scsi_cmd_allowed(cmd, filp->f_mode & FMODE_WRITE))
241 		return -EPERM;
242 	return 0;
243 }
244 
245 static int
open_wait(Sg_device * sdp,int flags)246 open_wait(Sg_device *sdp, int flags)
247 {
248 	int retval = 0;
249 
250 	if (flags & O_EXCL) {
251 		while (sdp->open_cnt > 0) {
252 			mutex_unlock(&sdp->open_rel_lock);
253 			retval = wait_event_interruptible(sdp->open_wait,
254 					(atomic_read(&sdp->detaching) ||
255 					 !sdp->open_cnt));
256 			mutex_lock(&sdp->open_rel_lock);
257 
258 			if (retval) /* -ERESTARTSYS */
259 				return retval;
260 			if (atomic_read(&sdp->detaching))
261 				return -ENODEV;
262 		}
263 	} else {
264 		while (sdp->exclude) {
265 			mutex_unlock(&sdp->open_rel_lock);
266 			retval = wait_event_interruptible(sdp->open_wait,
267 					(atomic_read(&sdp->detaching) ||
268 					 !sdp->exclude));
269 			mutex_lock(&sdp->open_rel_lock);
270 
271 			if (retval) /* -ERESTARTSYS */
272 				return retval;
273 			if (atomic_read(&sdp->detaching))
274 				return -ENODEV;
275 		}
276 	}
277 
278 	return retval;
279 }
280 
281 /* Returns 0 on success, else a negated errno value */
282 static int
sg_open(struct inode * inode,struct file * filp)283 sg_open(struct inode *inode, struct file *filp)
284 {
285 	int dev = iminor(inode);
286 	int flags = filp->f_flags;
287 	struct request_queue *q;
288 	struct scsi_device *device;
289 	Sg_device *sdp;
290 	Sg_fd *sfp;
291 	int retval;
292 
293 	nonseekable_open(inode, filp);
294 	if ((flags & O_EXCL) && (O_RDONLY == (flags & O_ACCMODE)))
295 		return -EPERM; /* Can't lock it with read only access */
296 	sdp = sg_get_dev(dev);
297 	if (IS_ERR(sdp))
298 		return PTR_ERR(sdp);
299 
300 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
301 				      "sg_open: flags=0x%x\n", flags));
302 
303 	/* This driver's module count bumped by fops_get in <linux/fs.h> */
304 	/* Prevent the device driver from vanishing while we sleep */
305 	device = sdp->device;
306 	retval = scsi_device_get(device);
307 	if (retval)
308 		goto sg_put;
309 
310 	/* scsi_block_when_processing_errors() may block so bypass
311 	 * check if O_NONBLOCK. Permits SCSI commands to be issued
312 	 * during error recovery. Tread carefully. */
313 	if (!((flags & O_NONBLOCK) ||
314 	      scsi_block_when_processing_errors(device))) {
315 		retval = -ENXIO;
316 		/* we are in error recovery for this device */
317 		goto sdp_put;
318 	}
319 
320 	mutex_lock(&sdp->open_rel_lock);
321 	if (flags & O_NONBLOCK) {
322 		if (flags & O_EXCL) {
323 			if (sdp->open_cnt > 0) {
324 				retval = -EBUSY;
325 				goto error_mutex_locked;
326 			}
327 		} else {
328 			if (sdp->exclude) {
329 				retval = -EBUSY;
330 				goto error_mutex_locked;
331 			}
332 		}
333 	} else {
334 		retval = open_wait(sdp, flags);
335 		if (retval) /* -ERESTARTSYS or -ENODEV */
336 			goto error_mutex_locked;
337 	}
338 
339 	/* N.B. at this point we are holding the open_rel_lock */
340 	if (flags & O_EXCL)
341 		sdp->exclude = true;
342 
343 	if (sdp->open_cnt < 1) {  /* no existing opens */
344 		sdp->sgdebug = 0;
345 		q = device->request_queue;
346 		sdp->sg_tablesize = queue_max_segments(q);
347 	}
348 	sfp = sg_add_sfp(sdp);
349 	if (IS_ERR(sfp)) {
350 		retval = PTR_ERR(sfp);
351 		goto out_undo;
352 	}
353 
354 	filp->private_data = sfp;
355 	sdp->open_cnt++;
356 	mutex_unlock(&sdp->open_rel_lock);
357 
358 	retval = 0;
359 sg_put:
360 	kref_put(&sdp->d_ref, sg_device_destroy);
361 	return retval;
362 
363 out_undo:
364 	if (flags & O_EXCL) {
365 		sdp->exclude = false;   /* undo if error */
366 		wake_up_interruptible(&sdp->open_wait);
367 	}
368 error_mutex_locked:
369 	mutex_unlock(&sdp->open_rel_lock);
370 sdp_put:
371 	kref_put(&sdp->d_ref, sg_device_destroy);
372 	scsi_device_put(device);
373 	return retval;
374 }
375 
376 /* Release resources associated with a successful sg_open()
377  * Returns 0 on success, else a negated errno value */
378 static int
sg_release(struct inode * inode,struct file * filp)379 sg_release(struct inode *inode, struct file *filp)
380 {
381 	Sg_device *sdp;
382 	Sg_fd *sfp;
383 
384 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
385 		return -ENXIO;
386 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp, "sg_release\n"));
387 
388 	mutex_lock(&sdp->open_rel_lock);
389 	sdp->open_cnt--;
390 
391 	/* possibly many open()s waiting on exlude clearing, start many;
392 	 * only open(O_EXCL)s wait on 0==open_cnt so only start one */
393 	if (sdp->exclude) {
394 		sdp->exclude = false;
395 		wake_up_interruptible_all(&sdp->open_wait);
396 	} else if (0 == sdp->open_cnt) {
397 		wake_up_interruptible(&sdp->open_wait);
398 	}
399 	mutex_unlock(&sdp->open_rel_lock);
400 	kref_put(&sfp->f_ref, sg_remove_sfp);
401 	return 0;
402 }
403 
get_sg_io_pack_id(int * pack_id,void __user * buf,size_t count)404 static int get_sg_io_pack_id(int *pack_id, void __user *buf, size_t count)
405 {
406 	struct sg_header __user *old_hdr = buf;
407 	int reply_len;
408 
409 	if (count >= SZ_SG_HEADER) {
410 		/* negative reply_len means v3 format, otherwise v1/v2 */
411 		if (get_user(reply_len, &old_hdr->reply_len))
412 			return -EFAULT;
413 
414 		if (reply_len >= 0)
415 			return get_user(*pack_id, &old_hdr->pack_id);
416 
417 		if (in_compat_syscall() &&
418 		    count >= sizeof(struct compat_sg_io_hdr)) {
419 			struct compat_sg_io_hdr __user *hp = buf;
420 
421 			return get_user(*pack_id, &hp->pack_id);
422 		}
423 
424 		if (count >= sizeof(struct sg_io_hdr)) {
425 			struct sg_io_hdr __user *hp = buf;
426 
427 			return get_user(*pack_id, &hp->pack_id);
428 		}
429 	}
430 
431 	/* no valid header was passed, so ignore the pack_id */
432 	*pack_id = -1;
433 	return 0;
434 }
435 
436 static ssize_t
sg_read(struct file * filp,char __user * buf,size_t count,loff_t * ppos)437 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
438 {
439 	Sg_device *sdp;
440 	Sg_fd *sfp;
441 	Sg_request *srp;
442 	int req_pack_id = -1;
443 	bool busy;
444 	sg_io_hdr_t *hp;
445 	struct sg_header *old_hdr;
446 	int retval;
447 
448 	/*
449 	 * This could cause a response to be stranded. Close the associated
450 	 * file descriptor to free up any resources being held.
451 	 */
452 	retval = sg_check_file_access(filp, __func__);
453 	if (retval)
454 		return retval;
455 
456 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
457 		return -ENXIO;
458 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
459 				      "sg_read: count=%d\n", (int) count));
460 
461 	if (sfp->force_packid)
462 		retval = get_sg_io_pack_id(&req_pack_id, buf, count);
463 	if (retval)
464 		return retval;
465 
466 	srp = sg_get_rq_mark(sfp, req_pack_id, &busy);
467 	if (!srp) {		/* now wait on packet to arrive */
468 		if (filp->f_flags & O_NONBLOCK)
469 			return -EAGAIN;
470 		retval = wait_event_interruptible(sfp->read_wait,
471 			((srp = sg_get_rq_mark(sfp, req_pack_id, &busy)) ||
472 			(!busy && atomic_read(&sdp->detaching))));
473 		if (!srp)
474 			/* signal or detaching */
475 			return retval ? retval : -ENODEV;
476 	}
477 	if (srp->header.interface_id != '\0')
478 		return sg_new_read(sfp, buf, count, srp);
479 
480 	hp = &srp->header;
481 	old_hdr = kzalloc(SZ_SG_HEADER, GFP_KERNEL);
482 	if (!old_hdr)
483 		return -ENOMEM;
484 
485 	old_hdr->reply_len = (int) hp->timeout;
486 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
487 	old_hdr->pack_id = hp->pack_id;
488 	old_hdr->twelve_byte =
489 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
490 	old_hdr->target_status = hp->masked_status;
491 	old_hdr->host_status = hp->host_status;
492 	old_hdr->driver_status = hp->driver_status;
493 	if ((CHECK_CONDITION & hp->masked_status) ||
494 	    (srp->sense_b[0] & 0x70) == 0x70) {
495 		old_hdr->driver_status = DRIVER_SENSE;
496 		memcpy(old_hdr->sense_buffer, srp->sense_b,
497 		       sizeof (old_hdr->sense_buffer));
498 	}
499 	switch (hp->host_status) {
500 	/* This setup of 'result' is for backward compatibility and is best
501 	   ignored by the user who should use target, host + driver status */
502 	case DID_OK:
503 	case DID_PASSTHROUGH:
504 	case DID_SOFT_ERROR:
505 		old_hdr->result = 0;
506 		break;
507 	case DID_NO_CONNECT:
508 	case DID_BUS_BUSY:
509 	case DID_TIME_OUT:
510 		old_hdr->result = EBUSY;
511 		break;
512 	case DID_BAD_TARGET:
513 	case DID_ABORT:
514 	case DID_PARITY:
515 	case DID_RESET:
516 	case DID_BAD_INTR:
517 		old_hdr->result = EIO;
518 		break;
519 	case DID_ERROR:
520 		old_hdr->result = (srp->sense_b[0] == 0 &&
521 				  hp->masked_status == GOOD) ? 0 : EIO;
522 		break;
523 	default:
524 		old_hdr->result = EIO;
525 		break;
526 	}
527 
528 	/* Now copy the result back to the user buffer.  */
529 	if (count >= SZ_SG_HEADER) {
530 		if (copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
531 			retval = -EFAULT;
532 			goto free_old_hdr;
533 		}
534 		buf += SZ_SG_HEADER;
535 		if (count > old_hdr->reply_len)
536 			count = old_hdr->reply_len;
537 		if (count > SZ_SG_HEADER) {
538 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
539 				retval = -EFAULT;
540 				goto free_old_hdr;
541 			}
542 		}
543 	} else
544 		count = (old_hdr->result == 0) ? 0 : -EIO;
545 	sg_finish_rem_req(srp);
546 	sg_remove_request(sfp, srp);
547 	retval = count;
548 free_old_hdr:
549 	kfree(old_hdr);
550 	return retval;
551 }
552 
553 static ssize_t
sg_new_read(Sg_fd * sfp,char __user * buf,size_t count,Sg_request * srp)554 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
555 {
556 	sg_io_hdr_t *hp = &srp->header;
557 	int err = 0, err2;
558 	int len;
559 
560 	if (in_compat_syscall()) {
561 		if (count < sizeof(struct compat_sg_io_hdr)) {
562 			err = -EINVAL;
563 			goto err_out;
564 		}
565 	} else if (count < SZ_SG_IO_HDR) {
566 		err = -EINVAL;
567 		goto err_out;
568 	}
569 	hp->sb_len_wr = 0;
570 	if ((hp->mx_sb_len > 0) && hp->sbp) {
571 		if ((CHECK_CONDITION & hp->masked_status) ||
572 		    (srp->sense_b[0] & 0x70) == 0x70) {
573 			int sb_len = SCSI_SENSE_BUFFERSIZE;
574 			sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
575 			len = 8 + (int) srp->sense_b[7];	/* Additional sense length field */
576 			len = (len > sb_len) ? sb_len : len;
577 			if (copy_to_user(hp->sbp, srp->sense_b, len)) {
578 				err = -EFAULT;
579 				goto err_out;
580 			}
581 			hp->driver_status = DRIVER_SENSE;
582 			hp->sb_len_wr = len;
583 		}
584 	}
585 	if (hp->masked_status || hp->host_status || hp->driver_status)
586 		hp->info |= SG_INFO_CHECK;
587 	err = put_sg_io_hdr(hp, buf);
588 err_out:
589 	err2 = sg_finish_rem_req(srp);
590 	sg_remove_request(sfp, srp);
591 	return err ? : err2 ? : count;
592 }
593 
594 static ssize_t
sg_write(struct file * filp,const char __user * buf,size_t count,loff_t * ppos)595 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
596 {
597 	int mxsize, cmd_size, k;
598 	int input_size, blocking;
599 	unsigned char opcode;
600 	Sg_device *sdp;
601 	Sg_fd *sfp;
602 	Sg_request *srp;
603 	struct sg_header old_hdr;
604 	sg_io_hdr_t *hp;
605 	unsigned char cmnd[SG_MAX_CDB_SIZE];
606 	int retval;
607 
608 	retval = sg_check_file_access(filp, __func__);
609 	if (retval)
610 		return retval;
611 
612 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
613 		return -ENXIO;
614 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
615 				      "sg_write: count=%d\n", (int) count));
616 	if (atomic_read(&sdp->detaching))
617 		return -ENODEV;
618 	if (!((filp->f_flags & O_NONBLOCK) ||
619 	      scsi_block_when_processing_errors(sdp->device)))
620 		return -ENXIO;
621 
622 	if (count < SZ_SG_HEADER)
623 		return -EIO;
624 	if (copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
625 		return -EFAULT;
626 	blocking = !(filp->f_flags & O_NONBLOCK);
627 	if (old_hdr.reply_len < 0)
628 		return sg_new_write(sfp, filp, buf, count,
629 				    blocking, 0, 0, NULL);
630 	if (count < (SZ_SG_HEADER + 6))
631 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
632 
633 	buf += SZ_SG_HEADER;
634 	if (get_user(opcode, buf))
635 		return -EFAULT;
636 
637 	if (!(srp = sg_add_request(sfp))) {
638 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sdp,
639 					      "sg_write: queue full\n"));
640 		return -EDOM;
641 	}
642 	mutex_lock(&sfp->f_mutex);
643 	if (sfp->next_cmd_len > 0) {
644 		cmd_size = sfp->next_cmd_len;
645 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
646 	} else {
647 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
648 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
649 			cmd_size = 12;
650 	}
651 	mutex_unlock(&sfp->f_mutex);
652 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
653 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
654 /* Determine buffer size.  */
655 	input_size = count - cmd_size;
656 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
657 	mxsize -= SZ_SG_HEADER;
658 	input_size -= SZ_SG_HEADER;
659 	if (input_size < 0) {
660 		sg_remove_request(sfp, srp);
661 		return -EIO;	/* User did not pass enough bytes for this command. */
662 	}
663 	hp = &srp->header;
664 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
665 	hp->cmd_len = (unsigned char) cmd_size;
666 	hp->iovec_count = 0;
667 	hp->mx_sb_len = 0;
668 	if (input_size > 0)
669 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
670 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
671 	else
672 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
673 	hp->dxfer_len = mxsize;
674 	if ((hp->dxfer_direction == SG_DXFER_TO_DEV) ||
675 	    (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV))
676 		hp->dxferp = (char __user *)buf + cmd_size;
677 	else
678 		hp->dxferp = NULL;
679 	hp->sbp = NULL;
680 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
681 	hp->flags = input_size;	/* structure abuse ... */
682 	hp->pack_id = old_hdr.pack_id;
683 	hp->usr_ptr = NULL;
684 	if (copy_from_user(cmnd, buf, cmd_size)) {
685 		sg_remove_request(sfp, srp);
686 		return -EFAULT;
687 	}
688 	/*
689 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
690 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
691 	 * is a non-zero input_size, so emit a warning.
692 	 */
693 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
694 		printk_ratelimited(KERN_WARNING
695 				   "sg_write: data in/out %d/%d bytes "
696 				   "for SCSI command 0x%x-- guessing "
697 				   "data in;\n   program %s not setting "
698 				   "count and/or reply_len properly\n",
699 				   old_hdr.reply_len - (int)SZ_SG_HEADER,
700 				   input_size, (unsigned int) cmnd[0],
701 				   current->comm);
702 	}
703 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
704 	return (k < 0) ? k : count;
705 }
706 
707 static ssize_t
sg_new_write(Sg_fd * sfp,struct file * file,const char __user * buf,size_t count,int blocking,int read_only,int sg_io_owned,Sg_request ** o_srp)708 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
709 		 size_t count, int blocking, int read_only, int sg_io_owned,
710 		 Sg_request **o_srp)
711 {
712 	int k;
713 	Sg_request *srp;
714 	sg_io_hdr_t *hp;
715 	unsigned char cmnd[SG_MAX_CDB_SIZE];
716 	int timeout;
717 	unsigned long ul_timeout;
718 
719 	if (count < SZ_SG_IO_HDR)
720 		return -EINVAL;
721 
722 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
723 	if (!(srp = sg_add_request(sfp))) {
724 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
725 					      "sg_new_write: queue full\n"));
726 		return -EDOM;
727 	}
728 	srp->sg_io_owned = sg_io_owned;
729 	hp = &srp->header;
730 	if (get_sg_io_hdr(hp, buf)) {
731 		sg_remove_request(sfp, srp);
732 		return -EFAULT;
733 	}
734 	if (hp->interface_id != 'S') {
735 		sg_remove_request(sfp, srp);
736 		return -ENOSYS;
737 	}
738 	if (hp->flags & SG_FLAG_MMAP_IO) {
739 		if (hp->dxfer_len > sfp->reserve.bufflen) {
740 			sg_remove_request(sfp, srp);
741 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
742 		}
743 		if (hp->flags & SG_FLAG_DIRECT_IO) {
744 			sg_remove_request(sfp, srp);
745 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
746 		}
747 		if (sfp->res_in_use) {
748 			sg_remove_request(sfp, srp);
749 			return -EBUSY;	/* reserve buffer already being used */
750 		}
751 	}
752 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
753 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
754 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
755 		sg_remove_request(sfp, srp);
756 		return -EMSGSIZE;
757 	}
758 	if (copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
759 		sg_remove_request(sfp, srp);
760 		return -EFAULT;
761 	}
762 	if (read_only && sg_allow_access(file, cmnd)) {
763 		sg_remove_request(sfp, srp);
764 		return -EPERM;
765 	}
766 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
767 	if (k < 0)
768 		return k;
769 	if (o_srp)
770 		*o_srp = srp;
771 	return count;
772 }
773 
774 static int
sg_common_write(Sg_fd * sfp,Sg_request * srp,unsigned char * cmnd,int timeout,int blocking)775 sg_common_write(Sg_fd * sfp, Sg_request * srp,
776 		unsigned char *cmnd, int timeout, int blocking)
777 {
778 	int k, at_head;
779 	Sg_device *sdp = sfp->parentdp;
780 	sg_io_hdr_t *hp = &srp->header;
781 
782 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
783 	hp->status = 0;
784 	hp->masked_status = 0;
785 	hp->msg_status = 0;
786 	hp->info = 0;
787 	hp->host_status = 0;
788 	hp->driver_status = 0;
789 	hp->resid = 0;
790 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
791 			"sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
792 			(int) cmnd[0], (int) hp->cmd_len));
793 
794 	if (hp->dxfer_len >= SZ_256M) {
795 		sg_remove_request(sfp, srp);
796 		return -EINVAL;
797 	}
798 
799 	k = sg_start_req(srp, cmnd);
800 	if (k) {
801 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
802 			"sg_common_write: start_req err=%d\n", k));
803 		sg_finish_rem_req(srp);
804 		sg_remove_request(sfp, srp);
805 		return k;	/* probably out of space --> ENOMEM */
806 	}
807 	if (atomic_read(&sdp->detaching)) {
808 		if (srp->bio) {
809 			blk_mq_free_request(srp->rq);
810 			srp->rq = NULL;
811 		}
812 
813 		sg_finish_rem_req(srp);
814 		sg_remove_request(sfp, srp);
815 		return -ENODEV;
816 	}
817 
818 	hp->duration = jiffies_to_msecs(jiffies);
819 	if (hp->interface_id != '\0' &&	/* v3 (or later) interface */
820 	    (SG_FLAG_Q_AT_TAIL & hp->flags))
821 		at_head = 0;
822 	else
823 		at_head = 1;
824 
825 	srp->rq->timeout = timeout;
826 	kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
827 	srp->rq->end_io = sg_rq_end_io;
828 	blk_execute_rq_nowait(srp->rq, at_head);
829 	return 0;
830 }
831 
srp_done(Sg_fd * sfp,Sg_request * srp)832 static int srp_done(Sg_fd *sfp, Sg_request *srp)
833 {
834 	unsigned long flags;
835 	int ret;
836 
837 	read_lock_irqsave(&sfp->rq_list_lock, flags);
838 	ret = srp->done;
839 	read_unlock_irqrestore(&sfp->rq_list_lock, flags);
840 	return ret;
841 }
842 
max_sectors_bytes(struct request_queue * q)843 static int max_sectors_bytes(struct request_queue *q)
844 {
845 	unsigned int max_sectors = queue_max_sectors(q);
846 
847 	max_sectors = min_t(unsigned int, max_sectors, INT_MAX >> 9);
848 
849 	return max_sectors << 9;
850 }
851 
852 static void
sg_fill_request_table(Sg_fd * sfp,sg_req_info_t * rinfo)853 sg_fill_request_table(Sg_fd *sfp, sg_req_info_t *rinfo)
854 {
855 	Sg_request *srp;
856 	int val;
857 	unsigned int ms;
858 
859 	val = 0;
860 	list_for_each_entry(srp, &sfp->rq_list, entry) {
861 		if (val >= SG_MAX_QUEUE)
862 			break;
863 		rinfo[val].req_state = srp->done + 1;
864 		rinfo[val].problem =
865 			srp->header.masked_status &
866 			srp->header.host_status &
867 			srp->header.driver_status;
868 		if (srp->done)
869 			rinfo[val].duration =
870 				srp->header.duration;
871 		else {
872 			ms = jiffies_to_msecs(jiffies);
873 			rinfo[val].duration =
874 				(ms > srp->header.duration) ?
875 				(ms - srp->header.duration) : 0;
876 		}
877 		rinfo[val].orphan = srp->orphan;
878 		rinfo[val].sg_io_owned = srp->sg_io_owned;
879 		rinfo[val].pack_id = srp->header.pack_id;
880 		rinfo[val].usr_ptr = srp->header.usr_ptr;
881 		val++;
882 	}
883 }
884 
885 #ifdef CONFIG_COMPAT
886 struct compat_sg_req_info { /* used by SG_GET_REQUEST_TABLE ioctl() */
887 	char req_state;
888 	char orphan;
889 	char sg_io_owned;
890 	char problem;
891 	int pack_id;
892 	compat_uptr_t usr_ptr;
893 	unsigned int duration;
894 	int unused;
895 };
896 
put_compat_request_table(struct compat_sg_req_info __user * o,struct sg_req_info * rinfo)897 static int put_compat_request_table(struct compat_sg_req_info __user *o,
898 				    struct sg_req_info *rinfo)
899 {
900 	int i;
901 	for (i = 0; i < SG_MAX_QUEUE; i++) {
902 		if (copy_to_user(o + i, rinfo + i, offsetof(sg_req_info_t, usr_ptr)) ||
903 		    put_user((uintptr_t)rinfo[i].usr_ptr, &o[i].usr_ptr) ||
904 		    put_user(rinfo[i].duration, &o[i].duration) ||
905 		    put_user(rinfo[i].unused, &o[i].unused))
906 			return -EFAULT;
907 	}
908 	return 0;
909 }
910 #endif
911 
912 static long
sg_ioctl_common(struct file * filp,Sg_device * sdp,Sg_fd * sfp,unsigned int cmd_in,void __user * p)913 sg_ioctl_common(struct file *filp, Sg_device *sdp, Sg_fd *sfp,
914 		unsigned int cmd_in, void __user *p)
915 {
916 	int __user *ip = p;
917 	int result, val, read_only;
918 	Sg_request *srp;
919 	unsigned long iflags;
920 
921 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
922 				   "sg_ioctl: cmd=0x%x\n", (int) cmd_in));
923 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
924 
925 	switch (cmd_in) {
926 	case SG_IO:
927 		if (atomic_read(&sdp->detaching))
928 			return -ENODEV;
929 		if (!scsi_block_when_processing_errors(sdp->device))
930 			return -ENXIO;
931 		result = sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
932 				 1, read_only, 1, &srp);
933 		if (result < 0)
934 			return result;
935 		result = wait_event_interruptible(sfp->read_wait,
936 			srp_done(sfp, srp));
937 		write_lock_irq(&sfp->rq_list_lock);
938 		if (srp->done) {
939 			srp->done = 2;
940 			write_unlock_irq(&sfp->rq_list_lock);
941 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
942 			return (result < 0) ? result : 0;
943 		}
944 		srp->orphan = 1;
945 		write_unlock_irq(&sfp->rq_list_lock);
946 		return result;	/* -ERESTARTSYS because signal hit process */
947 	case SG_SET_TIMEOUT:
948 		result = get_user(val, ip);
949 		if (result)
950 			return result;
951 		if (val < 0)
952 			return -EIO;
953 		if (val >= mult_frac((s64)INT_MAX, USER_HZ, HZ))
954 			val = min_t(s64, mult_frac((s64)INT_MAX, USER_HZ, HZ),
955 				    INT_MAX);
956 		sfp->timeout_user = val;
957 		sfp->timeout = mult_frac(val, HZ, USER_HZ);
958 
959 		return 0;
960 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
961 				/* strange ..., for backward compatibility */
962 		return sfp->timeout_user;
963 	case SG_SET_FORCE_LOW_DMA:
964 		/*
965 		 * N.B. This ioctl never worked properly, but failed to
966 		 * return an error value. So returning '0' to keep compability
967 		 * with legacy applications.
968 		 */
969 		return 0;
970 	case SG_GET_LOW_DMA:
971 		return put_user(0, ip);
972 	case SG_GET_SCSI_ID:
973 		{
974 			sg_scsi_id_t v;
975 
976 			if (atomic_read(&sdp->detaching))
977 				return -ENODEV;
978 			memset(&v, 0, sizeof(v));
979 			v.host_no = sdp->device->host->host_no;
980 			v.channel = sdp->device->channel;
981 			v.scsi_id = sdp->device->id;
982 			v.lun = sdp->device->lun;
983 			v.scsi_type = sdp->device->type;
984 			v.h_cmd_per_lun = sdp->device->host->cmd_per_lun;
985 			v.d_queue_depth = sdp->device->queue_depth;
986 			if (copy_to_user(p, &v, sizeof(sg_scsi_id_t)))
987 				return -EFAULT;
988 			return 0;
989 		}
990 	case SG_SET_FORCE_PACK_ID:
991 		result = get_user(val, ip);
992 		if (result)
993 			return result;
994 		sfp->force_packid = val ? 1 : 0;
995 		return 0;
996 	case SG_GET_PACK_ID:
997 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
998 		list_for_each_entry(srp, &sfp->rq_list, entry) {
999 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
1000 				read_unlock_irqrestore(&sfp->rq_list_lock,
1001 						       iflags);
1002 				return put_user(srp->header.pack_id, ip);
1003 			}
1004 		}
1005 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1006 		return put_user(-1, ip);
1007 	case SG_GET_NUM_WAITING:
1008 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
1009 		val = 0;
1010 		list_for_each_entry(srp, &sfp->rq_list, entry) {
1011 			if ((1 == srp->done) && (!srp->sg_io_owned))
1012 				++val;
1013 		}
1014 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1015 		return put_user(val, ip);
1016 	case SG_GET_SG_TABLESIZE:
1017 		return put_user(sdp->sg_tablesize, ip);
1018 	case SG_SET_RESERVED_SIZE:
1019 		result = get_user(val, ip);
1020 		if (result)
1021 			return result;
1022                 if (val < 0)
1023                         return -EINVAL;
1024 		val = min_t(int, val,
1025 			    max_sectors_bytes(sdp->device->request_queue));
1026 		mutex_lock(&sfp->f_mutex);
1027 		if (val != sfp->reserve.bufflen) {
1028 			if (sfp->mmap_called ||
1029 			    sfp->res_in_use) {
1030 				mutex_unlock(&sfp->f_mutex);
1031 				return -EBUSY;
1032 			}
1033 
1034 			sg_remove_scat(sfp, &sfp->reserve);
1035 			sg_build_reserve(sfp, val);
1036 		}
1037 		mutex_unlock(&sfp->f_mutex);
1038 		return 0;
1039 	case SG_GET_RESERVED_SIZE:
1040 		val = min_t(int, sfp->reserve.bufflen,
1041 			    max_sectors_bytes(sdp->device->request_queue));
1042 		return put_user(val, ip);
1043 	case SG_SET_COMMAND_Q:
1044 		result = get_user(val, ip);
1045 		if (result)
1046 			return result;
1047 		sfp->cmd_q = val ? 1 : 0;
1048 		return 0;
1049 	case SG_GET_COMMAND_Q:
1050 		return put_user((int) sfp->cmd_q, ip);
1051 	case SG_SET_KEEP_ORPHAN:
1052 		result = get_user(val, ip);
1053 		if (result)
1054 			return result;
1055 		sfp->keep_orphan = val;
1056 		return 0;
1057 	case SG_GET_KEEP_ORPHAN:
1058 		return put_user((int) sfp->keep_orphan, ip);
1059 	case SG_NEXT_CMD_LEN:
1060 		result = get_user(val, ip);
1061 		if (result)
1062 			return result;
1063 		if (val > SG_MAX_CDB_SIZE)
1064 			return -ENOMEM;
1065 		sfp->next_cmd_len = (val > 0) ? val : 0;
1066 		return 0;
1067 	case SG_GET_VERSION_NUM:
1068 		return put_user(sg_version_num, ip);
1069 	case SG_GET_ACCESS_COUNT:
1070 		/* faked - we don't have a real access count anymore */
1071 		val = (sdp->device ? 1 : 0);
1072 		return put_user(val, ip);
1073 	case SG_GET_REQUEST_TABLE:
1074 		{
1075 			sg_req_info_t *rinfo;
1076 
1077 			rinfo = kcalloc(SG_MAX_QUEUE, SZ_SG_REQ_INFO,
1078 					GFP_KERNEL);
1079 			if (!rinfo)
1080 				return -ENOMEM;
1081 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
1082 			sg_fill_request_table(sfp, rinfo);
1083 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1084 	#ifdef CONFIG_COMPAT
1085 			if (in_compat_syscall())
1086 				result = put_compat_request_table(p, rinfo);
1087 			else
1088 	#endif
1089 				result = copy_to_user(p, rinfo,
1090 						      SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1091 			result = result ? -EFAULT : 0;
1092 			kfree(rinfo);
1093 			return result;
1094 		}
1095 	case SG_EMULATED_HOST:
1096 		if (atomic_read(&sdp->detaching))
1097 			return -ENODEV;
1098 		return put_user(sdp->device->host->hostt->emulated, ip);
1099 	case SCSI_IOCTL_SEND_COMMAND:
1100 		if (atomic_read(&sdp->detaching))
1101 			return -ENODEV;
1102 		return scsi_ioctl(sdp->device, filp->f_mode & FMODE_WRITE,
1103 				  cmd_in, p);
1104 	case SG_SET_DEBUG:
1105 		result = get_user(val, ip);
1106 		if (result)
1107 			return result;
1108 		sdp->sgdebug = (char) val;
1109 		return 0;
1110 	case BLKSECTGET:
1111 		return put_user(max_sectors_bytes(sdp->device->request_queue),
1112 				ip);
1113 	case BLKTRACESETUP:
1114 		return blk_trace_setup(sdp->device->request_queue, sdp->name,
1115 				       MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1116 				       NULL, p);
1117 	case BLKTRACESTART:
1118 		return blk_trace_startstop(sdp->device->request_queue, 1);
1119 	case BLKTRACESTOP:
1120 		return blk_trace_startstop(sdp->device->request_queue, 0);
1121 	case BLKTRACETEARDOWN:
1122 		return blk_trace_remove(sdp->device->request_queue);
1123 	case SCSI_IOCTL_GET_IDLUN:
1124 	case SCSI_IOCTL_GET_BUS_NUMBER:
1125 	case SCSI_IOCTL_PROBE_HOST:
1126 	case SG_GET_TRANSFORM:
1127 	case SG_SCSI_RESET:
1128 		if (atomic_read(&sdp->detaching))
1129 			return -ENODEV;
1130 		break;
1131 	default:
1132 		if (read_only)
1133 			return -EPERM;	/* don't know so take safe approach */
1134 		break;
1135 	}
1136 
1137 	result = scsi_ioctl_block_when_processing_errors(sdp->device,
1138 			cmd_in, filp->f_flags & O_NDELAY);
1139 	if (result)
1140 		return result;
1141 
1142 	return -ENOIOCTLCMD;
1143 }
1144 
1145 static long
sg_ioctl(struct file * filp,unsigned int cmd_in,unsigned long arg)1146 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1147 {
1148 	void __user *p = (void __user *)arg;
1149 	Sg_device *sdp;
1150 	Sg_fd *sfp;
1151 	int ret;
1152 
1153 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1154 		return -ENXIO;
1155 
1156 	ret = sg_ioctl_common(filp, sdp, sfp, cmd_in, p);
1157 	if (ret != -ENOIOCTLCMD)
1158 		return ret;
1159 	return scsi_ioctl(sdp->device, filp->f_mode & FMODE_WRITE, cmd_in, p);
1160 }
1161 
1162 static __poll_t
sg_poll(struct file * filp,poll_table * wait)1163 sg_poll(struct file *filp, poll_table * wait)
1164 {
1165 	__poll_t res = 0;
1166 	Sg_device *sdp;
1167 	Sg_fd *sfp;
1168 	Sg_request *srp;
1169 	int count = 0;
1170 	unsigned long iflags;
1171 
1172 	sfp = filp->private_data;
1173 	if (!sfp)
1174 		return EPOLLERR;
1175 	sdp = sfp->parentdp;
1176 	if (!sdp)
1177 		return EPOLLERR;
1178 	poll_wait(filp, &sfp->read_wait, wait);
1179 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1180 	list_for_each_entry(srp, &sfp->rq_list, entry) {
1181 		/* if any read waiting, flag it */
1182 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1183 			res = EPOLLIN | EPOLLRDNORM;
1184 		++count;
1185 	}
1186 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1187 
1188 	if (atomic_read(&sdp->detaching))
1189 		res |= EPOLLHUP;
1190 	else if (!sfp->cmd_q) {
1191 		if (0 == count)
1192 			res |= EPOLLOUT | EPOLLWRNORM;
1193 	} else if (count < SG_MAX_QUEUE)
1194 		res |= EPOLLOUT | EPOLLWRNORM;
1195 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1196 				      "sg_poll: res=0x%x\n", (__force u32) res));
1197 	return res;
1198 }
1199 
1200 static int
sg_fasync(int fd,struct file * filp,int mode)1201 sg_fasync(int fd, struct file *filp, int mode)
1202 {
1203 	Sg_device *sdp;
1204 	Sg_fd *sfp;
1205 
1206 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1207 		return -ENXIO;
1208 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1209 				      "sg_fasync: mode=%d\n", mode));
1210 
1211 	return fasync_helper(fd, filp, mode, &sfp->async_qp);
1212 }
1213 
1214 static vm_fault_t
sg_vma_fault(struct vm_fault * vmf)1215 sg_vma_fault(struct vm_fault *vmf)
1216 {
1217 	struct vm_area_struct *vma = vmf->vma;
1218 	Sg_fd *sfp;
1219 	unsigned long offset, len, sa;
1220 	Sg_scatter_hold *rsv_schp;
1221 	int k, length;
1222 
1223 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1224 		return VM_FAULT_SIGBUS;
1225 	rsv_schp = &sfp->reserve;
1226 	offset = vmf->pgoff << PAGE_SHIFT;
1227 	if (offset >= rsv_schp->bufflen)
1228 		return VM_FAULT_SIGBUS;
1229 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1230 				      "sg_vma_fault: offset=%lu, scatg=%d\n",
1231 				      offset, rsv_schp->k_use_sg));
1232 	sa = vma->vm_start;
1233 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1234 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1235 		len = vma->vm_end - sa;
1236 		len = (len < length) ? len : length;
1237 		if (offset < len) {
1238 			struct page *page = nth_page(rsv_schp->pages[k],
1239 						     offset >> PAGE_SHIFT);
1240 			get_page(page);	/* increment page count */
1241 			vmf->page = page;
1242 			return 0; /* success */
1243 		}
1244 		sa += len;
1245 		offset -= len;
1246 	}
1247 
1248 	return VM_FAULT_SIGBUS;
1249 }
1250 
1251 static const struct vm_operations_struct sg_mmap_vm_ops = {
1252 	.fault = sg_vma_fault,
1253 };
1254 
1255 static int
sg_mmap(struct file * filp,struct vm_area_struct * vma)1256 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1257 {
1258 	Sg_fd *sfp;
1259 	unsigned long req_sz, len, sa;
1260 	Sg_scatter_hold *rsv_schp;
1261 	int k, length;
1262 	int ret = 0;
1263 
1264 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1265 		return -ENXIO;
1266 	req_sz = vma->vm_end - vma->vm_start;
1267 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sfp->parentdp,
1268 				      "sg_mmap starting, vm_start=%p, len=%d\n",
1269 				      (void *) vma->vm_start, (int) req_sz));
1270 	if (vma->vm_pgoff)
1271 		return -EINVAL;	/* want no offset */
1272 	rsv_schp = &sfp->reserve;
1273 	mutex_lock(&sfp->f_mutex);
1274 	if (req_sz > rsv_schp->bufflen) {
1275 		ret = -ENOMEM;	/* cannot map more than reserved buffer */
1276 		goto out;
1277 	}
1278 
1279 	sa = vma->vm_start;
1280 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1281 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1282 		len = vma->vm_end - sa;
1283 		len = (len < length) ? len : length;
1284 		sa += len;
1285 	}
1286 
1287 	sfp->mmap_called = 1;
1288 	vm_flags_set(vma, VM_IO | VM_DONTEXPAND | VM_DONTDUMP);
1289 	vma->vm_private_data = sfp;
1290 	vma->vm_ops = &sg_mmap_vm_ops;
1291 out:
1292 	mutex_unlock(&sfp->f_mutex);
1293 	return ret;
1294 }
1295 
1296 static void
sg_rq_end_io_usercontext(struct work_struct * work)1297 sg_rq_end_io_usercontext(struct work_struct *work)
1298 {
1299 	struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1300 	struct sg_fd *sfp = srp->parentfp;
1301 
1302 	sg_finish_rem_req(srp);
1303 	sg_remove_request(sfp, srp);
1304 	kref_put(&sfp->f_ref, sg_remove_sfp);
1305 }
1306 
1307 /*
1308  * This function is a "bottom half" handler that is called by the mid
1309  * level when a command is completed (or has failed).
1310  */
1311 static enum rq_end_io_ret
sg_rq_end_io(struct request * rq,blk_status_t status)1312 sg_rq_end_io(struct request *rq, blk_status_t status)
1313 {
1314 	struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
1315 	struct sg_request *srp = rq->end_io_data;
1316 	Sg_device *sdp;
1317 	Sg_fd *sfp;
1318 	unsigned long iflags;
1319 	unsigned int ms;
1320 	char *sense;
1321 	int result, resid, done = 1;
1322 
1323 	if (WARN_ON(srp->done != 0))
1324 		return RQ_END_IO_NONE;
1325 
1326 	sfp = srp->parentfp;
1327 	if (WARN_ON(sfp == NULL))
1328 		return RQ_END_IO_NONE;
1329 
1330 	sdp = sfp->parentdp;
1331 	if (unlikely(atomic_read(&sdp->detaching)))
1332 		pr_info("%s: device detaching\n", __func__);
1333 
1334 	sense = scmd->sense_buffer;
1335 	result = scmd->result;
1336 	resid = scmd->resid_len;
1337 
1338 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sdp,
1339 				      "sg_cmd_done: pack_id=%d, res=0x%x\n",
1340 				      srp->header.pack_id, result));
1341 	srp->header.resid = resid;
1342 	ms = jiffies_to_msecs(jiffies);
1343 	srp->header.duration = (ms > srp->header.duration) ?
1344 				(ms - srp->header.duration) : 0;
1345 	if (0 != result) {
1346 		struct scsi_sense_hdr sshdr;
1347 
1348 		srp->header.status = 0xff & result;
1349 		srp->header.masked_status = sg_status_byte(result);
1350 		srp->header.msg_status = COMMAND_COMPLETE;
1351 		srp->header.host_status = host_byte(result);
1352 		srp->header.driver_status = driver_byte(result);
1353 		if ((sdp->sgdebug > 0) &&
1354 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1355 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1356 			__scsi_print_sense(sdp->device, __func__, sense,
1357 					   SCSI_SENSE_BUFFERSIZE);
1358 
1359 		/* Following if statement is a patch supplied by Eric Youngdale */
1360 		if (driver_byte(result) != 0
1361 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1362 		    && !scsi_sense_is_deferred(&sshdr)
1363 		    && sshdr.sense_key == UNIT_ATTENTION
1364 		    && sdp->device->removable) {
1365 			/* Detected possible disc change. Set the bit - this */
1366 			/* may be used if there are filesystems using this device */
1367 			sdp->device->changed = 1;
1368 		}
1369 	}
1370 
1371 	if (scmd->sense_len)
1372 		memcpy(srp->sense_b, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
1373 
1374 	/* Rely on write phase to clean out srp status values, so no "else" */
1375 
1376 	/*
1377 	 * Free the request as soon as it is complete so that its resources
1378 	 * can be reused without waiting for userspace to read() the
1379 	 * result.  But keep the associated bio (if any) around until
1380 	 * blk_rq_unmap_user() can be called from user context.
1381 	 */
1382 	srp->rq = NULL;
1383 	blk_mq_free_request(rq);
1384 
1385 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1386 	if (unlikely(srp->orphan)) {
1387 		if (sfp->keep_orphan)
1388 			srp->sg_io_owned = 0;
1389 		else
1390 			done = 0;
1391 	}
1392 	srp->done = done;
1393 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1394 
1395 	if (likely(done)) {
1396 		/* Now wake up any sg_read() that is waiting for this
1397 		 * packet.
1398 		 */
1399 		wake_up_interruptible(&sfp->read_wait);
1400 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1401 		kref_put(&sfp->f_ref, sg_remove_sfp);
1402 	} else {
1403 		INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1404 		schedule_work(&srp->ew.work);
1405 	}
1406 	return RQ_END_IO_NONE;
1407 }
1408 
1409 static const struct file_operations sg_fops = {
1410 	.owner = THIS_MODULE,
1411 	.read = sg_read,
1412 	.write = sg_write,
1413 	.poll = sg_poll,
1414 	.unlocked_ioctl = sg_ioctl,
1415 	.compat_ioctl = compat_ptr_ioctl,
1416 	.open = sg_open,
1417 	.mmap = sg_mmap,
1418 	.release = sg_release,
1419 	.fasync = sg_fasync,
1420 	.llseek = no_llseek,
1421 };
1422 
1423 static struct class *sg_sysfs_class;
1424 
1425 static int sg_sysfs_valid = 0;
1426 
1427 static Sg_device *
sg_alloc(struct scsi_device * scsidp)1428 sg_alloc(struct scsi_device *scsidp)
1429 {
1430 	struct request_queue *q = scsidp->request_queue;
1431 	Sg_device *sdp;
1432 	unsigned long iflags;
1433 	int error;
1434 	u32 k;
1435 
1436 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1437 	if (!sdp) {
1438 		sdev_printk(KERN_WARNING, scsidp, "%s: kmalloc Sg_device "
1439 			    "failure\n", __func__);
1440 		return ERR_PTR(-ENOMEM);
1441 	}
1442 
1443 	idr_preload(GFP_KERNEL);
1444 	write_lock_irqsave(&sg_index_lock, iflags);
1445 
1446 	error = idr_alloc(&sg_index_idr, sdp, 0, SG_MAX_DEVS, GFP_NOWAIT);
1447 	if (error < 0) {
1448 		if (error == -ENOSPC) {
1449 			sdev_printk(KERN_WARNING, scsidp,
1450 				    "Unable to attach sg device type=%d, minor number exceeds %d\n",
1451 				    scsidp->type, SG_MAX_DEVS - 1);
1452 			error = -ENODEV;
1453 		} else {
1454 			sdev_printk(KERN_WARNING, scsidp, "%s: idr "
1455 				    "allocation Sg_device failure: %d\n",
1456 				    __func__, error);
1457 		}
1458 		goto out_unlock;
1459 	}
1460 	k = error;
1461 
1462 	SCSI_LOG_TIMEOUT(3, sdev_printk(KERN_INFO, scsidp,
1463 					"sg_alloc: dev=%d \n", k));
1464 	sprintf(sdp->name, "sg%d", k);
1465 	sdp->device = scsidp;
1466 	mutex_init(&sdp->open_rel_lock);
1467 	INIT_LIST_HEAD(&sdp->sfds);
1468 	init_waitqueue_head(&sdp->open_wait);
1469 	atomic_set(&sdp->detaching, 0);
1470 	rwlock_init(&sdp->sfd_lock);
1471 	sdp->sg_tablesize = queue_max_segments(q);
1472 	sdp->index = k;
1473 	kref_init(&sdp->d_ref);
1474 	error = 0;
1475 
1476 out_unlock:
1477 	write_unlock_irqrestore(&sg_index_lock, iflags);
1478 	idr_preload_end();
1479 
1480 	if (error) {
1481 		kfree(sdp);
1482 		return ERR_PTR(error);
1483 	}
1484 	return sdp;
1485 }
1486 
1487 static int
sg_add_device(struct device * cl_dev)1488 sg_add_device(struct device *cl_dev)
1489 {
1490 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1491 	Sg_device *sdp = NULL;
1492 	struct cdev * cdev = NULL;
1493 	int error;
1494 	unsigned long iflags;
1495 
1496 	if (!blk_get_queue(scsidp->request_queue)) {
1497 		pr_warn("%s: get scsi_device queue failed\n", __func__);
1498 		return -ENODEV;
1499 	}
1500 
1501 	error = -ENOMEM;
1502 	cdev = cdev_alloc();
1503 	if (!cdev) {
1504 		pr_warn("%s: cdev_alloc failed\n", __func__);
1505 		goto out;
1506 	}
1507 	cdev->owner = THIS_MODULE;
1508 	cdev->ops = &sg_fops;
1509 
1510 	sdp = sg_alloc(scsidp);
1511 	if (IS_ERR(sdp)) {
1512 		pr_warn("%s: sg_alloc failed\n", __func__);
1513 		error = PTR_ERR(sdp);
1514 		goto out;
1515 	}
1516 
1517 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1518 	if (error)
1519 		goto cdev_add_err;
1520 
1521 	sdp->cdev = cdev;
1522 	if (sg_sysfs_valid) {
1523 		struct device *sg_class_member;
1524 
1525 		sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1526 						MKDEV(SCSI_GENERIC_MAJOR,
1527 						      sdp->index),
1528 						sdp, "%s", sdp->name);
1529 		if (IS_ERR(sg_class_member)) {
1530 			pr_err("%s: device_create failed\n", __func__);
1531 			error = PTR_ERR(sg_class_member);
1532 			goto cdev_add_err;
1533 		}
1534 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1535 					  &sg_class_member->kobj, "generic");
1536 		if (error)
1537 			pr_err("%s: unable to make symlink 'generic' back "
1538 			       "to sg%d\n", __func__, sdp->index);
1539 	} else
1540 		pr_warn("%s: sg_sys Invalid\n", __func__);
1541 
1542 	sdev_printk(KERN_NOTICE, scsidp, "Attached scsi generic sg%d "
1543 		    "type %d\n", sdp->index, scsidp->type);
1544 
1545 	dev_set_drvdata(cl_dev, sdp);
1546 
1547 	return 0;
1548 
1549 cdev_add_err:
1550 	write_lock_irqsave(&sg_index_lock, iflags);
1551 	idr_remove(&sg_index_idr, sdp->index);
1552 	write_unlock_irqrestore(&sg_index_lock, iflags);
1553 	kfree(sdp);
1554 
1555 out:
1556 	if (cdev)
1557 		cdev_del(cdev);
1558 	blk_put_queue(scsidp->request_queue);
1559 	return error;
1560 }
1561 
1562 static void
sg_device_destroy(struct kref * kref)1563 sg_device_destroy(struct kref *kref)
1564 {
1565 	struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1566 	struct request_queue *q = sdp->device->request_queue;
1567 	unsigned long flags;
1568 
1569 	/* CAUTION!  Note that the device can still be found via idr_find()
1570 	 * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1571 	 * any other cleanup.
1572 	 */
1573 
1574 	blk_trace_remove(q);
1575 	blk_put_queue(q);
1576 
1577 	write_lock_irqsave(&sg_index_lock, flags);
1578 	idr_remove(&sg_index_idr, sdp->index);
1579 	write_unlock_irqrestore(&sg_index_lock, flags);
1580 
1581 	SCSI_LOG_TIMEOUT(3,
1582 		sg_printk(KERN_INFO, sdp, "sg_device_destroy\n"));
1583 
1584 	kfree(sdp);
1585 }
1586 
1587 static void
sg_remove_device(struct device * cl_dev)1588 sg_remove_device(struct device *cl_dev)
1589 {
1590 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1591 	Sg_device *sdp = dev_get_drvdata(cl_dev);
1592 	unsigned long iflags;
1593 	Sg_fd *sfp;
1594 	int val;
1595 
1596 	if (!sdp)
1597 		return;
1598 	/* want sdp->detaching non-zero as soon as possible */
1599 	val = atomic_inc_return(&sdp->detaching);
1600 	if (val > 1)
1601 		return; /* only want to do following once per device */
1602 
1603 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
1604 				      "%s\n", __func__));
1605 
1606 	read_lock_irqsave(&sdp->sfd_lock, iflags);
1607 	list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1608 		wake_up_interruptible_all(&sfp->read_wait);
1609 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1610 	}
1611 	wake_up_interruptible_all(&sdp->open_wait);
1612 	read_unlock_irqrestore(&sdp->sfd_lock, iflags);
1613 
1614 	sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1615 	device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1616 	cdev_del(sdp->cdev);
1617 	sdp->cdev = NULL;
1618 
1619 	kref_put(&sdp->d_ref, sg_device_destroy);
1620 }
1621 
1622 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1623 module_param_named(def_reserved_size, def_reserved_size, int,
1624 		   S_IRUGO | S_IWUSR);
1625 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1626 
1627 MODULE_AUTHOR("Douglas Gilbert");
1628 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1629 MODULE_LICENSE("GPL");
1630 MODULE_VERSION(SG_VERSION_STR);
1631 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1632 
1633 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1634                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1635 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1636 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1637 
1638 #ifdef CONFIG_SYSCTL
1639 #include <linux/sysctl.h>
1640 
1641 static struct ctl_table sg_sysctls[] = {
1642 	{
1643 		.procname	= "sg-big-buff",
1644 		.data		= &sg_big_buff,
1645 		.maxlen		= sizeof(int),
1646 		.mode		= 0444,
1647 		.proc_handler	= proc_dointvec,
1648 	},
1649 	{}
1650 };
1651 
1652 static struct ctl_table_header *hdr;
register_sg_sysctls(void)1653 static void register_sg_sysctls(void)
1654 {
1655 	if (!hdr)
1656 		hdr = register_sysctl("kernel", sg_sysctls);
1657 }
1658 
unregister_sg_sysctls(void)1659 static void unregister_sg_sysctls(void)
1660 {
1661 	if (hdr)
1662 		unregister_sysctl_table(hdr);
1663 }
1664 #else
1665 #define register_sg_sysctls() do { } while (0)
1666 #define unregister_sg_sysctls() do { } while (0)
1667 #endif /* CONFIG_SYSCTL */
1668 
1669 static int __init
init_sg(void)1670 init_sg(void)
1671 {
1672 	int rc;
1673 
1674 	if (scatter_elem_sz < PAGE_SIZE) {
1675 		scatter_elem_sz = PAGE_SIZE;
1676 		scatter_elem_sz_prev = scatter_elem_sz;
1677 	}
1678 	if (def_reserved_size >= 0)
1679 		sg_big_buff = def_reserved_size;
1680 	else
1681 		def_reserved_size = sg_big_buff;
1682 
1683 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1684 				    SG_MAX_DEVS, "sg");
1685 	if (rc)
1686 		return rc;
1687         sg_sysfs_class = class_create("scsi_generic");
1688         if ( IS_ERR(sg_sysfs_class) ) {
1689 		rc = PTR_ERR(sg_sysfs_class);
1690 		goto err_out;
1691         }
1692 	sg_sysfs_valid = 1;
1693 	rc = scsi_register_interface(&sg_interface);
1694 	if (0 == rc) {
1695 #ifdef CONFIG_SCSI_PROC_FS
1696 		sg_proc_init();
1697 #endif				/* CONFIG_SCSI_PROC_FS */
1698 		return 0;
1699 	}
1700 	class_destroy(sg_sysfs_class);
1701 	register_sg_sysctls();
1702 err_out:
1703 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1704 	return rc;
1705 }
1706 
1707 static void __exit
exit_sg(void)1708 exit_sg(void)
1709 {
1710 	unregister_sg_sysctls();
1711 #ifdef CONFIG_SCSI_PROC_FS
1712 	remove_proc_subtree("scsi/sg", NULL);
1713 #endif				/* CONFIG_SCSI_PROC_FS */
1714 	scsi_unregister_interface(&sg_interface);
1715 	class_destroy(sg_sysfs_class);
1716 	sg_sysfs_valid = 0;
1717 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1718 				 SG_MAX_DEVS);
1719 	idr_destroy(&sg_index_idr);
1720 }
1721 
1722 static int
sg_start_req(Sg_request * srp,unsigned char * cmd)1723 sg_start_req(Sg_request *srp, unsigned char *cmd)
1724 {
1725 	int res;
1726 	struct request *rq;
1727 	Sg_fd *sfp = srp->parentfp;
1728 	sg_io_hdr_t *hp = &srp->header;
1729 	int dxfer_len = (int) hp->dxfer_len;
1730 	int dxfer_dir = hp->dxfer_direction;
1731 	unsigned int iov_count = hp->iovec_count;
1732 	Sg_scatter_hold *req_schp = &srp->data;
1733 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1734 	struct request_queue *q = sfp->parentdp->device->request_queue;
1735 	struct rq_map_data *md, map_data;
1736 	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? ITER_SOURCE : ITER_DEST;
1737 	struct scsi_cmnd *scmd;
1738 
1739 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1740 				      "sg_start_req: dxfer_len=%d\n",
1741 				      dxfer_len));
1742 
1743 	/*
1744 	 * NOTE
1745 	 *
1746 	 * With scsi-mq enabled, there are a fixed number of preallocated
1747 	 * requests equal in number to shost->can_queue.  If all of the
1748 	 * preallocated requests are already in use, then scsi_alloc_request()
1749 	 * will sleep until an active command completes, freeing up a request.
1750 	 * Although waiting in an asynchronous interface is less than ideal, we
1751 	 * do not want to use BLK_MQ_REQ_NOWAIT here because userspace might
1752 	 * not expect an EWOULDBLOCK from this condition.
1753 	 */
1754 	rq = scsi_alloc_request(q, hp->dxfer_direction == SG_DXFER_TO_DEV ?
1755 			REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
1756 	if (IS_ERR(rq))
1757 		return PTR_ERR(rq);
1758 	scmd = blk_mq_rq_to_pdu(rq);
1759 
1760 	if (hp->cmd_len > sizeof(scmd->cmnd)) {
1761 		blk_mq_free_request(rq);
1762 		return -EINVAL;
1763 	}
1764 
1765 	memcpy(scmd->cmnd, cmd, hp->cmd_len);
1766 	scmd->cmd_len = hp->cmd_len;
1767 
1768 	srp->rq = rq;
1769 	rq->end_io_data = srp;
1770 	scmd->allowed = SG_DEFAULT_RETRIES;
1771 
1772 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1773 		return 0;
1774 
1775 	if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1776 	    dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1777 	    blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1778 		md = NULL;
1779 	else
1780 		md = &map_data;
1781 
1782 	if (md) {
1783 		mutex_lock(&sfp->f_mutex);
1784 		if (dxfer_len <= rsv_schp->bufflen &&
1785 		    !sfp->res_in_use) {
1786 			sfp->res_in_use = 1;
1787 			sg_link_reserve(sfp, srp, dxfer_len);
1788 		} else if (hp->flags & SG_FLAG_MMAP_IO) {
1789 			res = -EBUSY; /* sfp->res_in_use == 1 */
1790 			if (dxfer_len > rsv_schp->bufflen)
1791 				res = -ENOMEM;
1792 			mutex_unlock(&sfp->f_mutex);
1793 			return res;
1794 		} else {
1795 			res = sg_build_indirect(req_schp, sfp, dxfer_len);
1796 			if (res) {
1797 				mutex_unlock(&sfp->f_mutex);
1798 				return res;
1799 			}
1800 		}
1801 		mutex_unlock(&sfp->f_mutex);
1802 
1803 		md->pages = req_schp->pages;
1804 		md->page_order = req_schp->page_order;
1805 		md->nr_entries = req_schp->k_use_sg;
1806 		md->offset = 0;
1807 		md->null_mapped = hp->dxferp ? 0 : 1;
1808 		if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1809 			md->from_user = 1;
1810 		else
1811 			md->from_user = 0;
1812 	}
1813 
1814 	res = blk_rq_map_user_io(rq, md, hp->dxferp, hp->dxfer_len,
1815 			GFP_ATOMIC, iov_count, iov_count, 1, rw);
1816 	if (!res) {
1817 		srp->bio = rq->bio;
1818 
1819 		if (!md) {
1820 			req_schp->dio_in_use = 1;
1821 			hp->info |= SG_INFO_DIRECT_IO;
1822 		}
1823 	}
1824 	return res;
1825 }
1826 
1827 static int
sg_finish_rem_req(Sg_request * srp)1828 sg_finish_rem_req(Sg_request *srp)
1829 {
1830 	int ret = 0;
1831 
1832 	Sg_fd *sfp = srp->parentfp;
1833 	Sg_scatter_hold *req_schp = &srp->data;
1834 
1835 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1836 				      "sg_finish_rem_req: res_used=%d\n",
1837 				      (int) srp->res_used));
1838 	if (srp->bio)
1839 		ret = blk_rq_unmap_user(srp->bio);
1840 
1841 	if (srp->rq)
1842 		blk_mq_free_request(srp->rq);
1843 
1844 	if (srp->res_used)
1845 		sg_unlink_reserve(sfp, srp);
1846 	else
1847 		sg_remove_scat(sfp, req_schp);
1848 
1849 	return ret;
1850 }
1851 
1852 static int
sg_build_sgat(Sg_scatter_hold * schp,const Sg_fd * sfp,int tablesize)1853 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1854 {
1855 	int sg_bufflen = tablesize * sizeof(struct page *);
1856 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1857 
1858 	schp->pages = kzalloc(sg_bufflen, gfp_flags);
1859 	if (!schp->pages)
1860 		return -ENOMEM;
1861 	schp->sglist_len = sg_bufflen;
1862 	return tablesize;	/* number of scat_gath elements allocated */
1863 }
1864 
1865 static int
sg_build_indirect(Sg_scatter_hold * schp,Sg_fd * sfp,int buff_size)1866 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1867 {
1868 	int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1869 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1870 	int blk_size = buff_size, order;
1871 	gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN | __GFP_ZERO;
1872 
1873 	if (blk_size < 0)
1874 		return -EFAULT;
1875 	if (0 == blk_size)
1876 		++blk_size;	/* don't know why */
1877 	/* round request up to next highest SG_SECTOR_SZ byte boundary */
1878 	blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1879 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1880 		"sg_build_indirect: buff_size=%d, blk_size=%d\n",
1881 		buff_size, blk_size));
1882 
1883 	/* N.B. ret_sz carried into this block ... */
1884 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1885 	if (mx_sc_elems < 0)
1886 		return mx_sc_elems;	/* most likely -ENOMEM */
1887 
1888 	num = scatter_elem_sz;
1889 	if (unlikely(num != scatter_elem_sz_prev)) {
1890 		if (num < PAGE_SIZE) {
1891 			scatter_elem_sz = PAGE_SIZE;
1892 			scatter_elem_sz_prev = PAGE_SIZE;
1893 		} else
1894 			scatter_elem_sz_prev = num;
1895 	}
1896 
1897 	order = get_order(num);
1898 retry:
1899 	ret_sz = 1 << (PAGE_SHIFT + order);
1900 
1901 	for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1902 	     k++, rem_sz -= ret_sz) {
1903 
1904 		num = (rem_sz > scatter_elem_sz_prev) ?
1905 			scatter_elem_sz_prev : rem_sz;
1906 
1907 		schp->pages[k] = alloc_pages(gfp_mask, order);
1908 		if (!schp->pages[k])
1909 			goto out;
1910 
1911 		if (num == scatter_elem_sz_prev) {
1912 			if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1913 				scatter_elem_sz = ret_sz;
1914 				scatter_elem_sz_prev = ret_sz;
1915 			}
1916 		}
1917 
1918 		SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1919 				 "sg_build_indirect: k=%d, num=%d, ret_sz=%d\n",
1920 				 k, num, ret_sz));
1921 	}		/* end of for loop */
1922 
1923 	schp->page_order = order;
1924 	schp->k_use_sg = k;
1925 	SCSI_LOG_TIMEOUT(5, sg_printk(KERN_INFO, sfp->parentdp,
1926 			 "sg_build_indirect: k_use_sg=%d, rem_sz=%d\n",
1927 			 k, rem_sz));
1928 
1929 	schp->bufflen = blk_size;
1930 	if (rem_sz > 0)	/* must have failed */
1931 		return -ENOMEM;
1932 	return 0;
1933 out:
1934 	for (i = 0; i < k; i++)
1935 		__free_pages(schp->pages[i], order);
1936 
1937 	if (--order >= 0)
1938 		goto retry;
1939 
1940 	return -ENOMEM;
1941 }
1942 
1943 static void
sg_remove_scat(Sg_fd * sfp,Sg_scatter_hold * schp)1944 sg_remove_scat(Sg_fd * sfp, Sg_scatter_hold * schp)
1945 {
1946 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
1947 			 "sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1948 	if (schp->pages && schp->sglist_len > 0) {
1949 		if (!schp->dio_in_use) {
1950 			int k;
1951 
1952 			for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1953 				SCSI_LOG_TIMEOUT(5,
1954 					sg_printk(KERN_INFO, sfp->parentdp,
1955 					"sg_remove_scat: k=%d, pg=0x%p\n",
1956 					k, schp->pages[k]));
1957 				__free_pages(schp->pages[k], schp->page_order);
1958 			}
1959 
1960 			kfree(schp->pages);
1961 		}
1962 	}
1963 	memset(schp, 0, sizeof (*schp));
1964 }
1965 
1966 static int
sg_read_oxfer(Sg_request * srp,char __user * outp,int num_read_xfer)1967 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1968 {
1969 	Sg_scatter_hold *schp = &srp->data;
1970 	int k, num;
1971 
1972 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
1973 			 "sg_read_oxfer: num_read_xfer=%d\n",
1974 			 num_read_xfer));
1975 	if ((!outp) || (num_read_xfer <= 0))
1976 		return 0;
1977 
1978 	num = 1 << (PAGE_SHIFT + schp->page_order);
1979 	for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1980 		if (num > num_read_xfer) {
1981 			if (copy_to_user(outp, page_address(schp->pages[k]),
1982 					   num_read_xfer))
1983 				return -EFAULT;
1984 			break;
1985 		} else {
1986 			if (copy_to_user(outp, page_address(schp->pages[k]),
1987 					   num))
1988 				return -EFAULT;
1989 			num_read_xfer -= num;
1990 			if (num_read_xfer <= 0)
1991 				break;
1992 			outp += num;
1993 		}
1994 	}
1995 
1996 	return 0;
1997 }
1998 
1999 static void
sg_build_reserve(Sg_fd * sfp,int req_size)2000 sg_build_reserve(Sg_fd * sfp, int req_size)
2001 {
2002 	Sg_scatter_hold *schp = &sfp->reserve;
2003 
2004 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2005 			 "sg_build_reserve: req_size=%d\n", req_size));
2006 	do {
2007 		if (req_size < PAGE_SIZE)
2008 			req_size = PAGE_SIZE;
2009 		if (0 == sg_build_indirect(schp, sfp, req_size))
2010 			return;
2011 		else
2012 			sg_remove_scat(sfp, schp);
2013 		req_size >>= 1;	/* divide by 2 */
2014 	} while (req_size > (PAGE_SIZE / 2));
2015 }
2016 
2017 static void
sg_link_reserve(Sg_fd * sfp,Sg_request * srp,int size)2018 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
2019 {
2020 	Sg_scatter_hold *req_schp = &srp->data;
2021 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
2022 	int k, num, rem;
2023 
2024 	srp->res_used = 1;
2025 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,
2026 			 "sg_link_reserve: size=%d\n", size));
2027 	rem = size;
2028 
2029 	num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
2030 	for (k = 0; k < rsv_schp->k_use_sg; k++) {
2031 		if (rem <= num) {
2032 			req_schp->k_use_sg = k + 1;
2033 			req_schp->sglist_len = rsv_schp->sglist_len;
2034 			req_schp->pages = rsv_schp->pages;
2035 
2036 			req_schp->bufflen = size;
2037 			req_schp->page_order = rsv_schp->page_order;
2038 			break;
2039 		} else
2040 			rem -= num;
2041 	}
2042 
2043 	if (k >= rsv_schp->k_use_sg)
2044 		SCSI_LOG_TIMEOUT(1, sg_printk(KERN_INFO, sfp->parentdp,
2045 				 "sg_link_reserve: BAD size\n"));
2046 }
2047 
2048 static void
sg_unlink_reserve(Sg_fd * sfp,Sg_request * srp)2049 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
2050 {
2051 	Sg_scatter_hold *req_schp = &srp->data;
2052 
2053 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, srp->parentfp->parentdp,
2054 				      "sg_unlink_reserve: req->k_use_sg=%d\n",
2055 				      (int) req_schp->k_use_sg));
2056 	req_schp->k_use_sg = 0;
2057 	req_schp->bufflen = 0;
2058 	req_schp->pages = NULL;
2059 	req_schp->page_order = 0;
2060 	req_schp->sglist_len = 0;
2061 	srp->res_used = 0;
2062 	/* Called without mutex lock to avoid deadlock */
2063 	sfp->res_in_use = 0;
2064 }
2065 
2066 static Sg_request *
sg_get_rq_mark(Sg_fd * sfp,int pack_id,bool * busy)2067 sg_get_rq_mark(Sg_fd * sfp, int pack_id, bool *busy)
2068 {
2069 	Sg_request *resp;
2070 	unsigned long iflags;
2071 
2072 	*busy = false;
2073 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2074 	list_for_each_entry(resp, &sfp->rq_list, entry) {
2075 		/* look for requests that are not SG_IO owned */
2076 		if ((!resp->sg_io_owned) &&
2077 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
2078 			switch (resp->done) {
2079 			case 0: /* request active */
2080 				*busy = true;
2081 				break;
2082 			case 1: /* request done; response ready to return */
2083 				resp->done = 2;	/* guard against other readers */
2084 				write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2085 				return resp;
2086 			case 2: /* response already being returned */
2087 				break;
2088 			}
2089 		}
2090 	}
2091 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2092 	return NULL;
2093 }
2094 
2095 /* always adds to end of list */
2096 static Sg_request *
sg_add_request(Sg_fd * sfp)2097 sg_add_request(Sg_fd * sfp)
2098 {
2099 	int k;
2100 	unsigned long iflags;
2101 	Sg_request *rp = sfp->req_arr;
2102 
2103 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2104 	if (!list_empty(&sfp->rq_list)) {
2105 		if (!sfp->cmd_q)
2106 			goto out_unlock;
2107 
2108 		for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
2109 			if (!rp->parentfp)
2110 				break;
2111 		}
2112 		if (k >= SG_MAX_QUEUE)
2113 			goto out_unlock;
2114 	}
2115 	memset(rp, 0, sizeof (Sg_request));
2116 	rp->parentfp = sfp;
2117 	rp->header.duration = jiffies_to_msecs(jiffies);
2118 	list_add_tail(&rp->entry, &sfp->rq_list);
2119 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2120 	return rp;
2121 out_unlock:
2122 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2123 	return NULL;
2124 }
2125 
2126 /* Return of 1 for found; 0 for not found */
2127 static int
sg_remove_request(Sg_fd * sfp,Sg_request * srp)2128 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2129 {
2130 	unsigned long iflags;
2131 	int res = 0;
2132 
2133 	if (!sfp || !srp || list_empty(&sfp->rq_list))
2134 		return res;
2135 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2136 	if (!list_empty(&srp->entry)) {
2137 		list_del(&srp->entry);
2138 		srp->parentfp = NULL;
2139 		res = 1;
2140 	}
2141 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2142 
2143 	/*
2144 	 * If the device is detaching, wakeup any readers in case we just
2145 	 * removed the last response, which would leave nothing for them to
2146 	 * return other than -ENODEV.
2147 	 */
2148 	if (unlikely(atomic_read(&sfp->parentdp->detaching)))
2149 		wake_up_interruptible_all(&sfp->read_wait);
2150 
2151 	return res;
2152 }
2153 
2154 static Sg_fd *
sg_add_sfp(Sg_device * sdp)2155 sg_add_sfp(Sg_device * sdp)
2156 {
2157 	Sg_fd *sfp;
2158 	unsigned long iflags;
2159 	int bufflen;
2160 
2161 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2162 	if (!sfp)
2163 		return ERR_PTR(-ENOMEM);
2164 
2165 	init_waitqueue_head(&sfp->read_wait);
2166 	rwlock_init(&sfp->rq_list_lock);
2167 	INIT_LIST_HEAD(&sfp->rq_list);
2168 	kref_init(&sfp->f_ref);
2169 	mutex_init(&sfp->f_mutex);
2170 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2171 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2172 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2173 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2174 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2175 	sfp->parentdp = sdp;
2176 	write_lock_irqsave(&sdp->sfd_lock, iflags);
2177 	if (atomic_read(&sdp->detaching)) {
2178 		write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2179 		kfree(sfp);
2180 		return ERR_PTR(-ENODEV);
2181 	}
2182 	list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2183 	write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2184 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2185 				      "sg_add_sfp: sfp=0x%p\n", sfp));
2186 	if (unlikely(sg_big_buff != def_reserved_size))
2187 		sg_big_buff = def_reserved_size;
2188 
2189 	bufflen = min_t(int, sg_big_buff,
2190 			max_sectors_bytes(sdp->device->request_queue));
2191 	sg_build_reserve(sfp, bufflen);
2192 	SCSI_LOG_TIMEOUT(3, sg_printk(KERN_INFO, sdp,
2193 				      "sg_add_sfp: bufflen=%d, k_use_sg=%d\n",
2194 				      sfp->reserve.bufflen,
2195 				      sfp->reserve.k_use_sg));
2196 
2197 	kref_get(&sdp->d_ref);
2198 	__module_get(THIS_MODULE);
2199 	return sfp;
2200 }
2201 
2202 static void
sg_remove_sfp_usercontext(struct work_struct * work)2203 sg_remove_sfp_usercontext(struct work_struct *work)
2204 {
2205 	struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2206 	struct sg_device *sdp = sfp->parentdp;
2207 	struct scsi_device *device = sdp->device;
2208 	Sg_request *srp;
2209 	unsigned long iflags;
2210 
2211 	/* Cleanup any responses which were never read(). */
2212 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2213 	while (!list_empty(&sfp->rq_list)) {
2214 		srp = list_first_entry(&sfp->rq_list, Sg_request, entry);
2215 		sg_finish_rem_req(srp);
2216 		list_del(&srp->entry);
2217 		srp->parentfp = NULL;
2218 	}
2219 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2220 
2221 	if (sfp->reserve.bufflen > 0) {
2222 		SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2223 				"sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2224 				(int) sfp->reserve.bufflen,
2225 				(int) sfp->reserve.k_use_sg));
2226 		sg_remove_scat(sfp, &sfp->reserve);
2227 	}
2228 
2229 	SCSI_LOG_TIMEOUT(6, sg_printk(KERN_INFO, sdp,
2230 			"sg_remove_sfp: sfp=0x%p\n", sfp));
2231 	kfree(sfp);
2232 
2233 	kref_put(&sdp->d_ref, sg_device_destroy);
2234 	scsi_device_put(device);
2235 	module_put(THIS_MODULE);
2236 }
2237 
2238 static void
sg_remove_sfp(struct kref * kref)2239 sg_remove_sfp(struct kref *kref)
2240 {
2241 	struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2242 	struct sg_device *sdp = sfp->parentdp;
2243 	unsigned long iflags;
2244 
2245 	write_lock_irqsave(&sdp->sfd_lock, iflags);
2246 	list_del(&sfp->sfd_siblings);
2247 	write_unlock_irqrestore(&sdp->sfd_lock, iflags);
2248 
2249 	INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2250 	schedule_work(&sfp->ew.work);
2251 }
2252 
2253 #ifdef CONFIG_SCSI_PROC_FS
2254 static int
sg_idr_max_id(int id,void * p,void * data)2255 sg_idr_max_id(int id, void *p, void *data)
2256 {
2257 	int *k = data;
2258 
2259 	if (*k < id)
2260 		*k = id;
2261 
2262 	return 0;
2263 }
2264 
2265 static int
sg_last_dev(void)2266 sg_last_dev(void)
2267 {
2268 	int k = -1;
2269 	unsigned long iflags;
2270 
2271 	read_lock_irqsave(&sg_index_lock, iflags);
2272 	idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2273 	read_unlock_irqrestore(&sg_index_lock, iflags);
2274 	return k + 1;		/* origin 1 */
2275 }
2276 #endif
2277 
2278 /* must be called with sg_index_lock held */
sg_lookup_dev(int dev)2279 static Sg_device *sg_lookup_dev(int dev)
2280 {
2281 	return idr_find(&sg_index_idr, dev);
2282 }
2283 
2284 static Sg_device *
sg_get_dev(int dev)2285 sg_get_dev(int dev)
2286 {
2287 	struct sg_device *sdp;
2288 	unsigned long flags;
2289 
2290 	read_lock_irqsave(&sg_index_lock, flags);
2291 	sdp = sg_lookup_dev(dev);
2292 	if (!sdp)
2293 		sdp = ERR_PTR(-ENXIO);
2294 	else if (atomic_read(&sdp->detaching)) {
2295 		/* If sdp->detaching, then the refcount may already be 0, in
2296 		 * which case it would be a bug to do kref_get().
2297 		 */
2298 		sdp = ERR_PTR(-ENODEV);
2299 	} else
2300 		kref_get(&sdp->d_ref);
2301 	read_unlock_irqrestore(&sg_index_lock, flags);
2302 
2303 	return sdp;
2304 }
2305 
2306 #ifdef CONFIG_SCSI_PROC_FS
2307 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2308 
2309 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2310 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2311 			          size_t count, loff_t *off);
2312 static const struct proc_ops adio_proc_ops = {
2313 	.proc_open	= sg_proc_single_open_adio,
2314 	.proc_read	= seq_read,
2315 	.proc_lseek	= seq_lseek,
2316 	.proc_write	= sg_proc_write_adio,
2317 	.proc_release	= single_release,
2318 };
2319 
2320 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2321 static ssize_t sg_proc_write_dressz(struct file *filp,
2322 		const char __user *buffer, size_t count, loff_t *off);
2323 static const struct proc_ops dressz_proc_ops = {
2324 	.proc_open	= sg_proc_single_open_dressz,
2325 	.proc_read	= seq_read,
2326 	.proc_lseek	= seq_lseek,
2327 	.proc_write	= sg_proc_write_dressz,
2328 	.proc_release	= single_release,
2329 };
2330 
2331 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2332 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2333 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2334 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2335 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2336 static void dev_seq_stop(struct seq_file *s, void *v);
2337 static const struct seq_operations dev_seq_ops = {
2338 	.start = dev_seq_start,
2339 	.next  = dev_seq_next,
2340 	.stop  = dev_seq_stop,
2341 	.show  = sg_proc_seq_show_dev,
2342 };
2343 
2344 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2345 static const struct seq_operations devstrs_seq_ops = {
2346 	.start = dev_seq_start,
2347 	.next  = dev_seq_next,
2348 	.stop  = dev_seq_stop,
2349 	.show  = sg_proc_seq_show_devstrs,
2350 };
2351 
2352 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2353 static const struct seq_operations debug_seq_ops = {
2354 	.start = dev_seq_start,
2355 	.next  = dev_seq_next,
2356 	.stop  = dev_seq_stop,
2357 	.show  = sg_proc_seq_show_debug,
2358 };
2359 
2360 static int
sg_proc_init(void)2361 sg_proc_init(void)
2362 {
2363 	struct proc_dir_entry *p;
2364 
2365 	p = proc_mkdir("scsi/sg", NULL);
2366 	if (!p)
2367 		return 1;
2368 
2369 	proc_create("allow_dio", S_IRUGO | S_IWUSR, p, &adio_proc_ops);
2370 	proc_create_seq("debug", S_IRUGO, p, &debug_seq_ops);
2371 	proc_create("def_reserved_size", S_IRUGO | S_IWUSR, p, &dressz_proc_ops);
2372 	proc_create_single("device_hdr", S_IRUGO, p, sg_proc_seq_show_devhdr);
2373 	proc_create_seq("devices", S_IRUGO, p, &dev_seq_ops);
2374 	proc_create_seq("device_strs", S_IRUGO, p, &devstrs_seq_ops);
2375 	proc_create_single("version", S_IRUGO, p, sg_proc_seq_show_version);
2376 	return 0;
2377 }
2378 
2379 
sg_proc_seq_show_int(struct seq_file * s,void * v)2380 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2381 {
2382 	seq_printf(s, "%d\n", *((int *)s->private));
2383 	return 0;
2384 }
2385 
sg_proc_single_open_adio(struct inode * inode,struct file * file)2386 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2387 {
2388 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2389 }
2390 
2391 static ssize_t
sg_proc_write_adio(struct file * filp,const char __user * buffer,size_t count,loff_t * off)2392 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2393 		   size_t count, loff_t *off)
2394 {
2395 	int err;
2396 	unsigned long num;
2397 
2398 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2399 		return -EACCES;
2400 	err = kstrtoul_from_user(buffer, count, 0, &num);
2401 	if (err)
2402 		return err;
2403 	sg_allow_dio = num ? 1 : 0;
2404 	return count;
2405 }
2406 
sg_proc_single_open_dressz(struct inode * inode,struct file * file)2407 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2408 {
2409 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2410 }
2411 
2412 static ssize_t
sg_proc_write_dressz(struct file * filp,const char __user * buffer,size_t count,loff_t * off)2413 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2414 		     size_t count, loff_t *off)
2415 {
2416 	int err;
2417 	unsigned long k = ULONG_MAX;
2418 
2419 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2420 		return -EACCES;
2421 
2422 	err = kstrtoul_from_user(buffer, count, 0, &k);
2423 	if (err)
2424 		return err;
2425 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2426 		sg_big_buff = k;
2427 		return count;
2428 	}
2429 	return -ERANGE;
2430 }
2431 
sg_proc_seq_show_version(struct seq_file * s,void * v)2432 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2433 {
2434 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2435 		   sg_version_date);
2436 	return 0;
2437 }
2438 
sg_proc_seq_show_devhdr(struct seq_file * s,void * v)2439 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2440 {
2441 	seq_puts(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\tonline\n");
2442 	return 0;
2443 }
2444 
2445 struct sg_proc_deviter {
2446 	loff_t	index;
2447 	size_t	max;
2448 };
2449 
dev_seq_start(struct seq_file * s,loff_t * pos)2450 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2451 {
2452 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2453 
2454 	s->private = it;
2455 	if (! it)
2456 		return NULL;
2457 
2458 	it->index = *pos;
2459 	it->max = sg_last_dev();
2460 	if (it->index >= it->max)
2461 		return NULL;
2462 	return it;
2463 }
2464 
dev_seq_next(struct seq_file * s,void * v,loff_t * pos)2465 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2466 {
2467 	struct sg_proc_deviter * it = s->private;
2468 
2469 	*pos = ++it->index;
2470 	return (it->index < it->max) ? it : NULL;
2471 }
2472 
dev_seq_stop(struct seq_file * s,void * v)2473 static void dev_seq_stop(struct seq_file *s, void *v)
2474 {
2475 	kfree(s->private);
2476 }
2477 
sg_proc_seq_show_dev(struct seq_file * s,void * v)2478 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2479 {
2480 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2481 	Sg_device *sdp;
2482 	struct scsi_device *scsidp;
2483 	unsigned long iflags;
2484 
2485 	read_lock_irqsave(&sg_index_lock, iflags);
2486 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2487 	if ((NULL == sdp) || (NULL == sdp->device) ||
2488 	    (atomic_read(&sdp->detaching)))
2489 		seq_puts(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2490 	else {
2491 		scsidp = sdp->device;
2492 		seq_printf(s, "%d\t%d\t%d\t%llu\t%d\t%d\t%d\t%d\t%d\n",
2493 			      scsidp->host->host_no, scsidp->channel,
2494 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2495 			      1,
2496 			      (int) scsidp->queue_depth,
2497 			      (int) scsi_device_busy(scsidp),
2498 			      (int) scsi_device_online(scsidp));
2499 	}
2500 	read_unlock_irqrestore(&sg_index_lock, iflags);
2501 	return 0;
2502 }
2503 
sg_proc_seq_show_devstrs(struct seq_file * s,void * v)2504 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2505 {
2506 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2507 	Sg_device *sdp;
2508 	struct scsi_device *scsidp;
2509 	unsigned long iflags;
2510 
2511 	read_lock_irqsave(&sg_index_lock, iflags);
2512 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2513 	scsidp = sdp ? sdp->device : NULL;
2514 	if (sdp && scsidp && (!atomic_read(&sdp->detaching)))
2515 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2516 			   scsidp->vendor, scsidp->model, scsidp->rev);
2517 	else
2518 		seq_puts(s, "<no active device>\n");
2519 	read_unlock_irqrestore(&sg_index_lock, iflags);
2520 	return 0;
2521 }
2522 
2523 /* must be called while holding sg_index_lock */
sg_proc_debug_helper(struct seq_file * s,Sg_device * sdp)2524 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2525 {
2526 	int k, new_interface, blen, usg;
2527 	Sg_request *srp;
2528 	Sg_fd *fp;
2529 	const sg_io_hdr_t *hp;
2530 	const char * cp;
2531 	unsigned int ms;
2532 
2533 	k = 0;
2534 	list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2535 		k++;
2536 		read_lock(&fp->rq_list_lock); /* irqs already disabled */
2537 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2538 			   "(res)sgat=%d low_dma=%d\n", k,
2539 			   jiffies_to_msecs(fp->timeout),
2540 			   fp->reserve.bufflen,
2541 			   (int) fp->reserve.k_use_sg, 0);
2542 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=0\n",
2543 			   (int) fp->cmd_q, (int) fp->force_packid,
2544 			   (int) fp->keep_orphan);
2545 		list_for_each_entry(srp, &fp->rq_list, entry) {
2546 			hp = &srp->header;
2547 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2548 			if (srp->res_used) {
2549 				if (new_interface &&
2550 				    (SG_FLAG_MMAP_IO & hp->flags))
2551 					cp = "     mmap>> ";
2552 				else
2553 					cp = "     rb>> ";
2554 			} else {
2555 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2556 					cp = "     dio>> ";
2557 				else
2558 					cp = "     ";
2559 			}
2560 			seq_puts(s, cp);
2561 			blen = srp->data.bufflen;
2562 			usg = srp->data.k_use_sg;
2563 			seq_puts(s, srp->done ?
2564 				 ((1 == srp->done) ?  "rcv:" : "fin:")
2565 				  : "act:");
2566 			seq_printf(s, " id=%d blen=%d",
2567 				   srp->header.pack_id, blen);
2568 			if (srp->done)
2569 				seq_printf(s, " dur=%d", hp->duration);
2570 			else {
2571 				ms = jiffies_to_msecs(jiffies);
2572 				seq_printf(s, " t_o/elap=%d/%d",
2573 					(new_interface ? hp->timeout :
2574 						  jiffies_to_msecs(fp->timeout)),
2575 					(ms > hp->duration ? ms - hp->duration : 0));
2576 			}
2577 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2578 				   (int) srp->data.cmd_opcode);
2579 		}
2580 		if (list_empty(&fp->rq_list))
2581 			seq_puts(s, "     No requests active\n");
2582 		read_unlock(&fp->rq_list_lock);
2583 	}
2584 }
2585 
sg_proc_seq_show_debug(struct seq_file * s,void * v)2586 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2587 {
2588 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2589 	Sg_device *sdp;
2590 	unsigned long iflags;
2591 
2592 	if (it && (0 == it->index))
2593 		seq_printf(s, "max_active_device=%d  def_reserved_size=%d\n",
2594 			   (int)it->max, sg_big_buff);
2595 
2596 	read_lock_irqsave(&sg_index_lock, iflags);
2597 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2598 	if (NULL == sdp)
2599 		goto skip;
2600 	read_lock(&sdp->sfd_lock);
2601 	if (!list_empty(&sdp->sfds)) {
2602 		seq_printf(s, " >>> device=%s ", sdp->name);
2603 		if (atomic_read(&sdp->detaching))
2604 			seq_puts(s, "detaching pending close ");
2605 		else if (sdp->device) {
2606 			struct scsi_device *scsidp = sdp->device;
2607 
2608 			seq_printf(s, "%d:%d:%d:%llu   em=%d",
2609 				   scsidp->host->host_no,
2610 				   scsidp->channel, scsidp->id,
2611 				   scsidp->lun,
2612 				   scsidp->host->hostt->emulated);
2613 		}
2614 		seq_printf(s, " sg_tablesize=%d excl=%d open_cnt=%d\n",
2615 			   sdp->sg_tablesize, sdp->exclude, sdp->open_cnt);
2616 		sg_proc_debug_helper(s, sdp);
2617 	}
2618 	read_unlock(&sdp->sfd_lock);
2619 skip:
2620 	read_unlock_irqrestore(&sg_index_lock, iflags);
2621 	return 0;
2622 }
2623 
2624 #endif				/* CONFIG_SCSI_PROC_FS */
2625 
2626 module_init(init_sg);
2627 module_exit(exit_sg);
2628