xref: /openbmc/linux/drivers/scsi/sg.c (revision 9cdb81c7)
1 /*
2  *  History:
3  *  Started: Aug 9 by Lawrence Foard (entropy@world.std.com),
4  *           to allow user process control of SCSI devices.
5  *  Development Sponsored by Killy Corp. NY NY
6  *
7  * Original driver (sg.c):
8  *        Copyright (C) 1992 Lawrence Foard
9  * Version 2 and 3 extensions to driver:
10  *        Copyright (C) 1998 - 2005 Douglas Gilbert
11  *
12  *  Modified  19-JAN-1998  Richard Gooch <rgooch@atnf.csiro.au>  Devfs support
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2, or (at your option)
17  * any later version.
18  *
19  */
20 
21 static int sg_version_num = 30534;	/* 2 digits for each component */
22 #define SG_VERSION_STR "3.5.34"
23 
24 /*
25  *  D. P. Gilbert (dgilbert@interlog.com, dougg@triode.net.au), notes:
26  *      - scsi logging is available via SCSI_LOG_TIMEOUT macros. First
27  *        the kernel/module needs to be built with CONFIG_SCSI_LOGGING
28  *        (otherwise the macros compile to empty statements).
29  *
30  */
31 #include <linux/module.h>
32 
33 #include <linux/fs.h>
34 #include <linux/kernel.h>
35 #include <linux/sched.h>
36 #include <linux/string.h>
37 #include <linux/mm.h>
38 #include <linux/errno.h>
39 #include <linux/mtio.h>
40 #include <linux/ioctl.h>
41 #include <linux/slab.h>
42 #include <linux/fcntl.h>
43 #include <linux/init.h>
44 #include <linux/poll.h>
45 #include <linux/moduleparam.h>
46 #include <linux/cdev.h>
47 #include <linux/idr.h>
48 #include <linux/seq_file.h>
49 #include <linux/blkdev.h>
50 #include <linux/delay.h>
51 #include <linux/blktrace_api.h>
52 #include <linux/mutex.h>
53 #include <linux/ratelimit.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 = "20061027";
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 /*
77  * Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
78  * Then when using 32 bit integers x * m may overflow during the calculation.
79  * Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m
80  * calculates the same, but prevents the overflow when both m and d
81  * are "small" numbers (like HZ and USER_HZ).
82  * Of course an overflow is inavoidable if the result of muldiv doesn't fit
83  * in 32 bits.
84  */
85 #define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))
86 
87 #define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
88 
89 int sg_big_buff = SG_DEF_RESERVED_SIZE;
90 /* N.B. This variable is readable and writeable via
91    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
92    of this size (or less if there is not enough memory) will be reserved
93    for use by this file descriptor. [Deprecated usage: this variable is also
94    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
95    the kernel (i.e. it is not a module).] */
96 static int def_reserved_size = -1;	/* picks up init parameter */
97 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
98 
99 static int scatter_elem_sz = SG_SCATTER_SZ;
100 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
101 
102 #define SG_SECTOR_SZ 512
103 
104 static int sg_add(struct device *, struct class_interface *);
105 static void sg_remove(struct device *, struct class_interface *);
106 
107 static DEFINE_MUTEX(sg_mutex);
108 
109 static DEFINE_IDR(sg_index_idr);
110 static DEFINE_RWLOCK(sg_index_lock);	/* Also used to lock
111 							   file descriptor list for device */
112 
113 static struct class_interface sg_interface = {
114 	.add_dev	= sg_add,
115 	.remove_dev	= sg_remove,
116 };
117 
118 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
119 	unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
120 	unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
121 	unsigned bufflen;	/* Size of (aggregate) data buffer */
122 	struct page **pages;
123 	int page_order;
124 	char dio_in_use;	/* 0->indirect IO (or mmap), 1->dio */
125 	unsigned char cmd_opcode; /* first byte of command */
126 } Sg_scatter_hold;
127 
128 struct sg_device;		/* forward declarations */
129 struct sg_fd;
130 
131 typedef struct sg_request {	/* SG_MAX_QUEUE requests outstanding per file */
132 	struct sg_request *nextrp;	/* NULL -> tail request (slist) */
133 	struct sg_fd *parentfp;	/* NULL -> not in use */
134 	Sg_scatter_hold data;	/* hold buffer, perhaps scatter list */
135 	sg_io_hdr_t header;	/* scsi command+info, see <scsi/sg.h> */
136 	unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
137 	char res_used;		/* 1 -> using reserve buffer, 0 -> not ... */
138 	char orphan;		/* 1 -> drop on sight, 0 -> normal */
139 	char sg_io_owned;	/* 1 -> packet belongs to SG_IO */
140 	volatile char done;	/* 0->before bh, 1->before read, 2->read */
141 	struct request *rq;
142 	struct bio *bio;
143 	struct execute_work ew;
144 } Sg_request;
145 
146 typedef struct sg_fd {		/* holds the state of a file descriptor */
147 	struct list_head sfd_siblings;
148 	struct sg_device *parentdp;	/* owning device */
149 	wait_queue_head_t read_wait;	/* queue read until command done */
150 	rwlock_t rq_list_lock;	/* protect access to list in req_arr */
151 	int timeout;		/* defaults to SG_DEFAULT_TIMEOUT      */
152 	int timeout_user;	/* defaults to SG_DEFAULT_TIMEOUT_USER */
153 	Sg_scatter_hold reserve;	/* buffer held for this file descriptor */
154 	unsigned save_scat_len;	/* original length of trunc. scat. element */
155 	Sg_request *headrp;	/* head of request slist, NULL->empty */
156 	struct fasync_struct *async_qp;	/* used by asynchronous notification */
157 	Sg_request req_arr[SG_MAX_QUEUE];	/* used as singly-linked list */
158 	char low_dma;		/* as in parent but possibly overridden to 1 */
159 	char force_packid;	/* 1 -> pack_id input to read(), 0 -> ignored */
160 	volatile char closed;	/* 1 -> fd closed but request(s) outstanding */
161 	char cmd_q;		/* 1 -> allow command queuing, 0 -> don't */
162 	char next_cmd_len;	/* 0 -> automatic (def), >0 -> use on next write() */
163 	char keep_orphan;	/* 0 -> drop orphan (def), 1 -> keep for read() */
164 	char mmap_called;	/* 0 -> mmap() never called on this fd */
165 	struct kref f_ref;
166 	struct execute_work ew;
167 } Sg_fd;
168 
169 typedef struct sg_device { /* holds the state of each scsi generic device */
170 	struct scsi_device *device;
171 	wait_queue_head_t o_excl_wait;	/* queue open() when O_EXCL in use */
172 	int sg_tablesize;	/* adapter's max scatter-gather table size */
173 	u32 index;		/* device index number */
174 	struct list_head sfds;
175 	volatile char detached;	/* 0->attached, 1->detached pending removal */
176 	volatile char exclude;	/* opened for exclusive access */
177 	char sgdebug;		/* 0->off, 1->sense, 9->dump dev, 10-> all devs */
178 	struct gendisk *disk;
179 	struct cdev * cdev;	/* char_dev [sysfs: /sys/cdev/major/sg<n>] */
180 	struct kref d_ref;
181 } Sg_device;
182 
183 /* tasklet or soft irq callback */
184 static void sg_rq_end_io(struct request *rq, int uptodate);
185 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
186 static int sg_finish_rem_req(Sg_request * srp);
187 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
188 static ssize_t sg_new_read(Sg_fd * sfp, char __user *buf, size_t count,
189 			   Sg_request * srp);
190 static ssize_t sg_new_write(Sg_fd *sfp, struct file *file,
191 			const char __user *buf, size_t count, int blocking,
192 			int read_only, int sg_io_owned, Sg_request **o_srp);
193 static int sg_common_write(Sg_fd * sfp, Sg_request * srp,
194 			   unsigned char *cmnd, int timeout, int blocking);
195 static int sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer);
196 static void sg_remove_scat(Sg_scatter_hold * schp);
197 static void sg_build_reserve(Sg_fd * sfp, int req_size);
198 static void sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size);
199 static void sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp);
200 static Sg_fd *sg_add_sfp(Sg_device * sdp, int dev);
201 static void sg_remove_sfp(struct kref *);
202 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
203 static Sg_request *sg_add_request(Sg_fd * sfp);
204 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
205 static int sg_res_in_use(Sg_fd * sfp);
206 static Sg_device *sg_get_dev(int dev);
207 static void sg_put_dev(Sg_device *sdp);
208 
209 #define SZ_SG_HEADER sizeof(struct sg_header)
210 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
211 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
212 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
213 
214 static int sg_allow_access(struct file *filp, unsigned char *cmd)
215 {
216 	struct sg_fd *sfp = filp->private_data;
217 
218 	if (sfp->parentdp->device->type == TYPE_SCANNER)
219 		return 0;
220 
221 	return blk_verify_command(cmd, filp->f_mode & FMODE_WRITE);
222 }
223 
224 static int
225 sg_open(struct inode *inode, struct file *filp)
226 {
227 	int dev = iminor(inode);
228 	int flags = filp->f_flags;
229 	struct request_queue *q;
230 	Sg_device *sdp;
231 	Sg_fd *sfp;
232 	int res;
233 	int retval;
234 
235 	mutex_lock(&sg_mutex);
236 	nonseekable_open(inode, filp);
237 	SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
238 	sdp = sg_get_dev(dev);
239 	if (IS_ERR(sdp)) {
240 		retval = PTR_ERR(sdp);
241 		sdp = NULL;
242 		goto sg_put;
243 	}
244 
245 	/* This driver's module count bumped by fops_get in <linux/fs.h> */
246 	/* Prevent the device driver from vanishing while we sleep */
247 	retval = scsi_device_get(sdp->device);
248 	if (retval)
249 		goto sg_put;
250 
251 	retval = scsi_autopm_get_device(sdp->device);
252 	if (retval)
253 		goto sdp_put;
254 
255 	if (!((flags & O_NONBLOCK) ||
256 	      scsi_block_when_processing_errors(sdp->device))) {
257 		retval = -ENXIO;
258 		/* we are in error recovery for this device */
259 		goto error_out;
260 	}
261 
262 	if (flags & O_EXCL) {
263 		if (O_RDONLY == (flags & O_ACCMODE)) {
264 			retval = -EPERM; /* Can't lock it with read only access */
265 			goto error_out;
266 		}
267 		if (!list_empty(&sdp->sfds) && (flags & O_NONBLOCK)) {
268 			retval = -EBUSY;
269 			goto error_out;
270 		}
271 		res = 0;
272 		__wait_event_interruptible(sdp->o_excl_wait,
273 					   ((!list_empty(&sdp->sfds) || sdp->exclude) ? 0 : (sdp->exclude = 1)), res);
274 		if (res) {
275 			retval = res;	/* -ERESTARTSYS because signal hit process */
276 			goto error_out;
277 		}
278 	} else if (sdp->exclude) {	/* some other fd has an exclusive lock on dev */
279 		if (flags & O_NONBLOCK) {
280 			retval = -EBUSY;
281 			goto error_out;
282 		}
283 		res = 0;
284 		__wait_event_interruptible(sdp->o_excl_wait, (!sdp->exclude),
285 					   res);
286 		if (res) {
287 			retval = res;	/* -ERESTARTSYS because signal hit process */
288 			goto error_out;
289 		}
290 	}
291 	if (sdp->detached) {
292 		retval = -ENODEV;
293 		goto error_out;
294 	}
295 	if (list_empty(&sdp->sfds)) {	/* no existing opens on this device */
296 		sdp->sgdebug = 0;
297 		q = sdp->device->request_queue;
298 		sdp->sg_tablesize = queue_max_segments(q);
299 	}
300 	if ((sfp = sg_add_sfp(sdp, dev)))
301 		filp->private_data = sfp;
302 	else {
303 		if (flags & O_EXCL) {
304 			sdp->exclude = 0;	/* undo if error */
305 			wake_up_interruptible(&sdp->o_excl_wait);
306 		}
307 		retval = -ENOMEM;
308 		goto error_out;
309 	}
310 	retval = 0;
311 error_out:
312 	if (retval) {
313 		scsi_autopm_put_device(sdp->device);
314 sdp_put:
315 		scsi_device_put(sdp->device);
316 	}
317 sg_put:
318 	if (sdp)
319 		sg_put_dev(sdp);
320 	mutex_unlock(&sg_mutex);
321 	return retval;
322 }
323 
324 /* Following function was formerly called 'sg_close' */
325 static int
326 sg_release(struct inode *inode, struct file *filp)
327 {
328 	Sg_device *sdp;
329 	Sg_fd *sfp;
330 
331 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
332 		return -ENXIO;
333 	SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
334 
335 	sfp->closed = 1;
336 
337 	sdp->exclude = 0;
338 	wake_up_interruptible(&sdp->o_excl_wait);
339 
340 	scsi_autopm_put_device(sdp->device);
341 	kref_put(&sfp->f_ref, sg_remove_sfp);
342 	return 0;
343 }
344 
345 static ssize_t
346 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
347 {
348 	Sg_device *sdp;
349 	Sg_fd *sfp;
350 	Sg_request *srp;
351 	int req_pack_id = -1;
352 	sg_io_hdr_t *hp;
353 	struct sg_header *old_hdr = NULL;
354 	int retval = 0;
355 
356 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
357 		return -ENXIO;
358 	SCSI_LOG_TIMEOUT(3, printk("sg_read: %s, count=%d\n",
359 				   sdp->disk->disk_name, (int) count));
360 
361 	if (!access_ok(VERIFY_WRITE, buf, count))
362 		return -EFAULT;
363 	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
364 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
365 		if (!old_hdr)
366 			return -ENOMEM;
367 		if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
368 			retval = -EFAULT;
369 			goto free_old_hdr;
370 		}
371 		if (old_hdr->reply_len < 0) {
372 			if (count >= SZ_SG_IO_HDR) {
373 				sg_io_hdr_t *new_hdr;
374 				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
375 				if (!new_hdr) {
376 					retval = -ENOMEM;
377 					goto free_old_hdr;
378 				}
379 				retval =__copy_from_user
380 				    (new_hdr, buf, SZ_SG_IO_HDR);
381 				req_pack_id = new_hdr->pack_id;
382 				kfree(new_hdr);
383 				if (retval) {
384 					retval = -EFAULT;
385 					goto free_old_hdr;
386 				}
387 			}
388 		} else
389 			req_pack_id = old_hdr->pack_id;
390 	}
391 	srp = sg_get_rq_mark(sfp, req_pack_id);
392 	if (!srp) {		/* now wait on packet to arrive */
393 		if (sdp->detached) {
394 			retval = -ENODEV;
395 			goto free_old_hdr;
396 		}
397 		if (filp->f_flags & O_NONBLOCK) {
398 			retval = -EAGAIN;
399 			goto free_old_hdr;
400 		}
401 		while (1) {
402 			retval = 0; /* following macro beats race condition */
403 			__wait_event_interruptible(sfp->read_wait,
404 				(sdp->detached ||
405 				(srp = sg_get_rq_mark(sfp, req_pack_id))),
406 				retval);
407 			if (sdp->detached) {
408 				retval = -ENODEV;
409 				goto free_old_hdr;
410 			}
411 			if (0 == retval)
412 				break;
413 
414 			/* -ERESTARTSYS as signal hit process */
415 			goto free_old_hdr;
416 		}
417 	}
418 	if (srp->header.interface_id != '\0') {
419 		retval = sg_new_read(sfp, buf, count, srp);
420 		goto free_old_hdr;
421 	}
422 
423 	hp = &srp->header;
424 	if (old_hdr == NULL) {
425 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
426 		if (! old_hdr) {
427 			retval = -ENOMEM;
428 			goto free_old_hdr;
429 		}
430 	}
431 	memset(old_hdr, 0, SZ_SG_HEADER);
432 	old_hdr->reply_len = (int) hp->timeout;
433 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
434 	old_hdr->pack_id = hp->pack_id;
435 	old_hdr->twelve_byte =
436 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
437 	old_hdr->target_status = hp->masked_status;
438 	old_hdr->host_status = hp->host_status;
439 	old_hdr->driver_status = hp->driver_status;
440 	if ((CHECK_CONDITION & hp->masked_status) ||
441 	    (DRIVER_SENSE & hp->driver_status))
442 		memcpy(old_hdr->sense_buffer, srp->sense_b,
443 		       sizeof (old_hdr->sense_buffer));
444 	switch (hp->host_status) {
445 	/* This setup of 'result' is for backward compatibility and is best
446 	   ignored by the user who should use target, host + driver status */
447 	case DID_OK:
448 	case DID_PASSTHROUGH:
449 	case DID_SOFT_ERROR:
450 		old_hdr->result = 0;
451 		break;
452 	case DID_NO_CONNECT:
453 	case DID_BUS_BUSY:
454 	case DID_TIME_OUT:
455 		old_hdr->result = EBUSY;
456 		break;
457 	case DID_BAD_TARGET:
458 	case DID_ABORT:
459 	case DID_PARITY:
460 	case DID_RESET:
461 	case DID_BAD_INTR:
462 		old_hdr->result = EIO;
463 		break;
464 	case DID_ERROR:
465 		old_hdr->result = (srp->sense_b[0] == 0 &&
466 				  hp->masked_status == GOOD) ? 0 : EIO;
467 		break;
468 	default:
469 		old_hdr->result = EIO;
470 		break;
471 	}
472 
473 	/* Now copy the result back to the user buffer.  */
474 	if (count >= SZ_SG_HEADER) {
475 		if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
476 			retval = -EFAULT;
477 			goto free_old_hdr;
478 		}
479 		buf += SZ_SG_HEADER;
480 		if (count > old_hdr->reply_len)
481 			count = old_hdr->reply_len;
482 		if (count > SZ_SG_HEADER) {
483 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
484 				retval = -EFAULT;
485 				goto free_old_hdr;
486 			}
487 		}
488 	} else
489 		count = (old_hdr->result == 0) ? 0 : -EIO;
490 	sg_finish_rem_req(srp);
491 	retval = count;
492 free_old_hdr:
493 	kfree(old_hdr);
494 	return retval;
495 }
496 
497 static ssize_t
498 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
499 {
500 	sg_io_hdr_t *hp = &srp->header;
501 	int err = 0;
502 	int len;
503 
504 	if (count < SZ_SG_IO_HDR) {
505 		err = -EINVAL;
506 		goto err_out;
507 	}
508 	hp->sb_len_wr = 0;
509 	if ((hp->mx_sb_len > 0) && hp->sbp) {
510 		if ((CHECK_CONDITION & hp->masked_status) ||
511 		    (DRIVER_SENSE & hp->driver_status)) {
512 			int sb_len = SCSI_SENSE_BUFFERSIZE;
513 			sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
514 			len = 8 + (int) srp->sense_b[7];	/* Additional sense length field */
515 			len = (len > sb_len) ? sb_len : len;
516 			if (copy_to_user(hp->sbp, srp->sense_b, len)) {
517 				err = -EFAULT;
518 				goto err_out;
519 			}
520 			hp->sb_len_wr = len;
521 		}
522 	}
523 	if (hp->masked_status || hp->host_status || hp->driver_status)
524 		hp->info |= SG_INFO_CHECK;
525 	if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
526 		err = -EFAULT;
527 		goto err_out;
528 	}
529 err_out:
530 	err = sg_finish_rem_req(srp);
531 	return (0 == err) ? count : err;
532 }
533 
534 static ssize_t
535 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
536 {
537 	int mxsize, cmd_size, k;
538 	int input_size, blocking;
539 	unsigned char opcode;
540 	Sg_device *sdp;
541 	Sg_fd *sfp;
542 	Sg_request *srp;
543 	struct sg_header old_hdr;
544 	sg_io_hdr_t *hp;
545 	unsigned char cmnd[MAX_COMMAND_SIZE];
546 
547 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
548 		return -ENXIO;
549 	SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n",
550 				   sdp->disk->disk_name, (int) count));
551 	if (sdp->detached)
552 		return -ENODEV;
553 	if (!((filp->f_flags & O_NONBLOCK) ||
554 	      scsi_block_when_processing_errors(sdp->device)))
555 		return -ENXIO;
556 
557 	if (!access_ok(VERIFY_READ, buf, count))
558 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
559 	if (count < SZ_SG_HEADER)
560 		return -EIO;
561 	if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
562 		return -EFAULT;
563 	blocking = !(filp->f_flags & O_NONBLOCK);
564 	if (old_hdr.reply_len < 0)
565 		return sg_new_write(sfp, filp, buf, count,
566 				    blocking, 0, 0, NULL);
567 	if (count < (SZ_SG_HEADER + 6))
568 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
569 
570 	if (!(srp = sg_add_request(sfp))) {
571 		SCSI_LOG_TIMEOUT(1, printk("sg_write: queue full\n"));
572 		return -EDOM;
573 	}
574 	buf += SZ_SG_HEADER;
575 	__get_user(opcode, buf);
576 	if (sfp->next_cmd_len > 0) {
577 		if (sfp->next_cmd_len > MAX_COMMAND_SIZE) {
578 			SCSI_LOG_TIMEOUT(1, printk("sg_write: command length too long\n"));
579 			sfp->next_cmd_len = 0;
580 			sg_remove_request(sfp, srp);
581 			return -EIO;
582 		}
583 		cmd_size = sfp->next_cmd_len;
584 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
585 	} else {
586 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
587 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
588 			cmd_size = 12;
589 	}
590 	SCSI_LOG_TIMEOUT(4, printk(
591 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
592 /* Determine buffer size.  */
593 	input_size = count - cmd_size;
594 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
595 	mxsize -= SZ_SG_HEADER;
596 	input_size -= SZ_SG_HEADER;
597 	if (input_size < 0) {
598 		sg_remove_request(sfp, srp);
599 		return -EIO;	/* User did not pass enough bytes for this command. */
600 	}
601 	hp = &srp->header;
602 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
603 	hp->cmd_len = (unsigned char) cmd_size;
604 	hp->iovec_count = 0;
605 	hp->mx_sb_len = 0;
606 	if (input_size > 0)
607 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
608 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
609 	else
610 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
611 	hp->dxfer_len = mxsize;
612 	if (hp->dxfer_direction == SG_DXFER_TO_DEV)
613 		hp->dxferp = (char __user *)buf + cmd_size;
614 	else
615 		hp->dxferp = NULL;
616 	hp->sbp = NULL;
617 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
618 	hp->flags = input_size;	/* structure abuse ... */
619 	hp->pack_id = old_hdr.pack_id;
620 	hp->usr_ptr = NULL;
621 	if (__copy_from_user(cmnd, buf, cmd_size))
622 		return -EFAULT;
623 	/*
624 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
625 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
626 	 * is a non-zero input_size, so emit a warning.
627 	 */
628 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
629 		static char cmd[TASK_COMM_LEN];
630 		if (strcmp(current->comm, cmd)) {
631 			printk_ratelimited(KERN_WARNING
632 					   "sg_write: data in/out %d/%d bytes "
633 					   "for SCSI command 0x%x-- guessing "
634 					   "data in;\n   program %s not setting "
635 					   "count and/or reply_len properly\n",
636 					   old_hdr.reply_len - (int)SZ_SG_HEADER,
637 					   input_size, (unsigned int) cmnd[0],
638 					   current->comm);
639 			strcpy(cmd, current->comm);
640 		}
641 	}
642 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
643 	return (k < 0) ? k : count;
644 }
645 
646 static ssize_t
647 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
648 		 size_t count, int blocking, int read_only, int sg_io_owned,
649 		 Sg_request **o_srp)
650 {
651 	int k;
652 	Sg_request *srp;
653 	sg_io_hdr_t *hp;
654 	unsigned char cmnd[MAX_COMMAND_SIZE];
655 	int timeout;
656 	unsigned long ul_timeout;
657 
658 	if (count < SZ_SG_IO_HDR)
659 		return -EINVAL;
660 	if (!access_ok(VERIFY_READ, buf, count))
661 		return -EFAULT; /* protects following copy_from_user()s + get_user()s */
662 
663 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
664 	if (!(srp = sg_add_request(sfp))) {
665 		SCSI_LOG_TIMEOUT(1, printk("sg_new_write: queue full\n"));
666 		return -EDOM;
667 	}
668 	srp->sg_io_owned = sg_io_owned;
669 	hp = &srp->header;
670 	if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
671 		sg_remove_request(sfp, srp);
672 		return -EFAULT;
673 	}
674 	if (hp->interface_id != 'S') {
675 		sg_remove_request(sfp, srp);
676 		return -ENOSYS;
677 	}
678 	if (hp->flags & SG_FLAG_MMAP_IO) {
679 		if (hp->dxfer_len > sfp->reserve.bufflen) {
680 			sg_remove_request(sfp, srp);
681 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
682 		}
683 		if (hp->flags & SG_FLAG_DIRECT_IO) {
684 			sg_remove_request(sfp, srp);
685 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
686 		}
687 		if (sg_res_in_use(sfp)) {
688 			sg_remove_request(sfp, srp);
689 			return -EBUSY;	/* reserve buffer already being used */
690 		}
691 	}
692 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
693 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
694 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
695 		sg_remove_request(sfp, srp);
696 		return -EMSGSIZE;
697 	}
698 	if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
699 		sg_remove_request(sfp, srp);
700 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
701 	}
702 	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
703 		sg_remove_request(sfp, srp);
704 		return -EFAULT;
705 	}
706 	if (read_only && sg_allow_access(file, cmnd)) {
707 		sg_remove_request(sfp, srp);
708 		return -EPERM;
709 	}
710 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
711 	if (k < 0)
712 		return k;
713 	if (o_srp)
714 		*o_srp = srp;
715 	return count;
716 }
717 
718 static int
719 sg_common_write(Sg_fd * sfp, Sg_request * srp,
720 		unsigned char *cmnd, int timeout, int blocking)
721 {
722 	int k, data_dir;
723 	Sg_device *sdp = sfp->parentdp;
724 	sg_io_hdr_t *hp = &srp->header;
725 
726 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
727 	hp->status = 0;
728 	hp->masked_status = 0;
729 	hp->msg_status = 0;
730 	hp->info = 0;
731 	hp->host_status = 0;
732 	hp->driver_status = 0;
733 	hp->resid = 0;
734 	SCSI_LOG_TIMEOUT(4, printk("sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
735 			  (int) cmnd[0], (int) hp->cmd_len));
736 
737 	k = sg_start_req(srp, cmnd);
738 	if (k) {
739 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: start_req err=%d\n", k));
740 		sg_finish_rem_req(srp);
741 		return k;	/* probably out of space --> ENOMEM */
742 	}
743 	if (sdp->detached) {
744 		if (srp->bio)
745 			blk_end_request_all(srp->rq, -EIO);
746 		sg_finish_rem_req(srp);
747 		return -ENODEV;
748 	}
749 
750 	switch (hp->dxfer_direction) {
751 	case SG_DXFER_TO_FROM_DEV:
752 	case SG_DXFER_FROM_DEV:
753 		data_dir = DMA_FROM_DEVICE;
754 		break;
755 	case SG_DXFER_TO_DEV:
756 		data_dir = DMA_TO_DEVICE;
757 		break;
758 	case SG_DXFER_UNKNOWN:
759 		data_dir = DMA_BIDIRECTIONAL;
760 		break;
761 	default:
762 		data_dir = DMA_NONE;
763 		break;
764 	}
765 	hp->duration = jiffies_to_msecs(jiffies);
766 
767 	srp->rq->timeout = timeout;
768 	kref_get(&sfp->f_ref); /* sg_rq_end_io() does kref_put(). */
769 	blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
770 			      srp->rq, 1, sg_rq_end_io);
771 	return 0;
772 }
773 
774 static int
775 sg_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
776 {
777 	void __user *p = (void __user *)arg;
778 	int __user *ip = p;
779 	int result, val, read_only;
780 	Sg_device *sdp;
781 	Sg_fd *sfp;
782 	Sg_request *srp;
783 	unsigned long iflags;
784 
785 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
786 		return -ENXIO;
787 
788 	SCSI_LOG_TIMEOUT(3, printk("sg_ioctl: %s, cmd=0x%x\n",
789 				   sdp->disk->disk_name, (int) cmd_in));
790 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
791 
792 	switch (cmd_in) {
793 	case SG_IO:
794 		{
795 			int blocking = 1;	/* ignore O_NONBLOCK flag */
796 
797 			if (sdp->detached)
798 				return -ENODEV;
799 			if (!scsi_block_when_processing_errors(sdp->device))
800 				return -ENXIO;
801 			if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
802 				return -EFAULT;
803 			result =
804 			    sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
805 					 blocking, read_only, 1, &srp);
806 			if (result < 0)
807 				return result;
808 			while (1) {
809 				result = 0;	/* following macro to beat race condition */
810 				__wait_event_interruptible(sfp->read_wait,
811 					(srp->done || sdp->detached),
812 					result);
813 				if (sdp->detached)
814 					return -ENODEV;
815 				write_lock_irq(&sfp->rq_list_lock);
816 				if (srp->done) {
817 					srp->done = 2;
818 					write_unlock_irq(&sfp->rq_list_lock);
819 					break;
820 				}
821 				srp->orphan = 1;
822 				write_unlock_irq(&sfp->rq_list_lock);
823 				return result;	/* -ERESTARTSYS because signal hit process */
824 			}
825 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
826 			return (result < 0) ? result : 0;
827 		}
828 	case SG_SET_TIMEOUT:
829 		result = get_user(val, ip);
830 		if (result)
831 			return result;
832 		if (val < 0)
833 			return -EIO;
834 		if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
835 		    val = MULDIV (INT_MAX, USER_HZ, HZ);
836 		sfp->timeout_user = val;
837 		sfp->timeout = MULDIV (val, HZ, USER_HZ);
838 
839 		return 0;
840 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
841 				/* strange ..., for backward compatibility */
842 		return sfp->timeout_user;
843 	case SG_SET_FORCE_LOW_DMA:
844 		result = get_user(val, ip);
845 		if (result)
846 			return result;
847 		if (val) {
848 			sfp->low_dma = 1;
849 			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
850 				val = (int) sfp->reserve.bufflen;
851 				sg_remove_scat(&sfp->reserve);
852 				sg_build_reserve(sfp, val);
853 			}
854 		} else {
855 			if (sdp->detached)
856 				return -ENODEV;
857 			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
858 		}
859 		return 0;
860 	case SG_GET_LOW_DMA:
861 		return put_user((int) sfp->low_dma, ip);
862 	case SG_GET_SCSI_ID:
863 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
864 			return -EFAULT;
865 		else {
866 			sg_scsi_id_t __user *sg_idp = p;
867 
868 			if (sdp->detached)
869 				return -ENODEV;
870 			__put_user((int) sdp->device->host->host_no,
871 				   &sg_idp->host_no);
872 			__put_user((int) sdp->device->channel,
873 				   &sg_idp->channel);
874 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
875 			__put_user((int) sdp->device->lun, &sg_idp->lun);
876 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
877 			__put_user((short) sdp->device->host->cmd_per_lun,
878 				   &sg_idp->h_cmd_per_lun);
879 			__put_user((short) sdp->device->queue_depth,
880 				   &sg_idp->d_queue_depth);
881 			__put_user(0, &sg_idp->unused[0]);
882 			__put_user(0, &sg_idp->unused[1]);
883 			return 0;
884 		}
885 	case SG_SET_FORCE_PACK_ID:
886 		result = get_user(val, ip);
887 		if (result)
888 			return result;
889 		sfp->force_packid = val ? 1 : 0;
890 		return 0;
891 	case SG_GET_PACK_ID:
892 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
893 			return -EFAULT;
894 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
895 		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
896 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
897 				read_unlock_irqrestore(&sfp->rq_list_lock,
898 						       iflags);
899 				__put_user(srp->header.pack_id, ip);
900 				return 0;
901 			}
902 		}
903 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
904 		__put_user(-1, ip);
905 		return 0;
906 	case SG_GET_NUM_WAITING:
907 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
908 		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
909 			if ((1 == srp->done) && (!srp->sg_io_owned))
910 				++val;
911 		}
912 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
913 		return put_user(val, ip);
914 	case SG_GET_SG_TABLESIZE:
915 		return put_user(sdp->sg_tablesize, ip);
916 	case SG_SET_RESERVED_SIZE:
917 		result = get_user(val, ip);
918 		if (result)
919 			return result;
920                 if (val < 0)
921                         return -EINVAL;
922 		val = min_t(int, val,
923 			    queue_max_sectors(sdp->device->request_queue) * 512);
924 		if (val != sfp->reserve.bufflen) {
925 			if (sg_res_in_use(sfp) || sfp->mmap_called)
926 				return -EBUSY;
927 			sg_remove_scat(&sfp->reserve);
928 			sg_build_reserve(sfp, val);
929 		}
930 		return 0;
931 	case SG_GET_RESERVED_SIZE:
932 		val = min_t(int, sfp->reserve.bufflen,
933 			    queue_max_sectors(sdp->device->request_queue) * 512);
934 		return put_user(val, ip);
935 	case SG_SET_COMMAND_Q:
936 		result = get_user(val, ip);
937 		if (result)
938 			return result;
939 		sfp->cmd_q = val ? 1 : 0;
940 		return 0;
941 	case SG_GET_COMMAND_Q:
942 		return put_user((int) sfp->cmd_q, ip);
943 	case SG_SET_KEEP_ORPHAN:
944 		result = get_user(val, ip);
945 		if (result)
946 			return result;
947 		sfp->keep_orphan = val;
948 		return 0;
949 	case SG_GET_KEEP_ORPHAN:
950 		return put_user((int) sfp->keep_orphan, ip);
951 	case SG_NEXT_CMD_LEN:
952 		result = get_user(val, ip);
953 		if (result)
954 			return result;
955 		sfp->next_cmd_len = (val > 0) ? val : 0;
956 		return 0;
957 	case SG_GET_VERSION_NUM:
958 		return put_user(sg_version_num, ip);
959 	case SG_GET_ACCESS_COUNT:
960 		/* faked - we don't have a real access count anymore */
961 		val = (sdp->device ? 1 : 0);
962 		return put_user(val, ip);
963 	case SG_GET_REQUEST_TABLE:
964 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
965 			return -EFAULT;
966 		else {
967 			sg_req_info_t *rinfo;
968 			unsigned int ms;
969 
970 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
971 								GFP_KERNEL);
972 			if (!rinfo)
973 				return -ENOMEM;
974 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
975 			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
976 			     ++val, srp = srp ? srp->nextrp : srp) {
977 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
978 				if (srp) {
979 					rinfo[val].req_state = srp->done + 1;
980 					rinfo[val].problem =
981 					    srp->header.masked_status &
982 					    srp->header.host_status &
983 					    srp->header.driver_status;
984 					if (srp->done)
985 						rinfo[val].duration =
986 							srp->header.duration;
987 					else {
988 						ms = jiffies_to_msecs(jiffies);
989 						rinfo[val].duration =
990 						    (ms > srp->header.duration) ?
991 						    (ms - srp->header.duration) : 0;
992 					}
993 					rinfo[val].orphan = srp->orphan;
994 					rinfo[val].sg_io_owned =
995 							srp->sg_io_owned;
996 					rinfo[val].pack_id =
997 							srp->header.pack_id;
998 					rinfo[val].usr_ptr =
999 							srp->header.usr_ptr;
1000 				}
1001 			}
1002 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1003 			result = __copy_to_user(p, rinfo,
1004 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1005 			result = result ? -EFAULT : 0;
1006 			kfree(rinfo);
1007 			return result;
1008 		}
1009 	case SG_EMULATED_HOST:
1010 		if (sdp->detached)
1011 			return -ENODEV;
1012 		return put_user(sdp->device->host->hostt->emulated, ip);
1013 	case SG_SCSI_RESET:
1014 		if (sdp->detached)
1015 			return -ENODEV;
1016 		if (filp->f_flags & O_NONBLOCK) {
1017 			if (scsi_host_in_recovery(sdp->device->host))
1018 				return -EBUSY;
1019 		} else if (!scsi_block_when_processing_errors(sdp->device))
1020 			return -EBUSY;
1021 		result = get_user(val, ip);
1022 		if (result)
1023 			return result;
1024 		if (SG_SCSI_RESET_NOTHING == val)
1025 			return 0;
1026 		switch (val) {
1027 		case SG_SCSI_RESET_DEVICE:
1028 			val = SCSI_TRY_RESET_DEVICE;
1029 			break;
1030 		case SG_SCSI_RESET_TARGET:
1031 			val = SCSI_TRY_RESET_TARGET;
1032 			break;
1033 		case SG_SCSI_RESET_BUS:
1034 			val = SCSI_TRY_RESET_BUS;
1035 			break;
1036 		case SG_SCSI_RESET_HOST:
1037 			val = SCSI_TRY_RESET_HOST;
1038 			break;
1039 		default:
1040 			return -EINVAL;
1041 		}
1042 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1043 			return -EACCES;
1044 		return (scsi_reset_provider(sdp->device, val) ==
1045 			SUCCESS) ? 0 : -EIO;
1046 	case SCSI_IOCTL_SEND_COMMAND:
1047 		if (sdp->detached)
1048 			return -ENODEV;
1049 		if (read_only) {
1050 			unsigned char opcode = WRITE_6;
1051 			Scsi_Ioctl_Command __user *siocp = p;
1052 
1053 			if (copy_from_user(&opcode, siocp->data, 1))
1054 				return -EFAULT;
1055 			if (sg_allow_access(filp, &opcode))
1056 				return -EPERM;
1057 		}
1058 		return sg_scsi_ioctl(sdp->device->request_queue, NULL, filp->f_mode, p);
1059 	case SG_SET_DEBUG:
1060 		result = get_user(val, ip);
1061 		if (result)
1062 			return result;
1063 		sdp->sgdebug = (char) val;
1064 		return 0;
1065 	case SCSI_IOCTL_GET_IDLUN:
1066 	case SCSI_IOCTL_GET_BUS_NUMBER:
1067 	case SCSI_IOCTL_PROBE_HOST:
1068 	case SG_GET_TRANSFORM:
1069 		if (sdp->detached)
1070 			return -ENODEV;
1071 		return scsi_ioctl(sdp->device, cmd_in, p);
1072 	case BLKSECTGET:
1073 		return put_user(queue_max_sectors(sdp->device->request_queue) * 512,
1074 				ip);
1075 	case BLKTRACESETUP:
1076 		return blk_trace_setup(sdp->device->request_queue,
1077 				       sdp->disk->disk_name,
1078 				       MKDEV(SCSI_GENERIC_MAJOR, sdp->index),
1079 				       NULL,
1080 				       (char *)arg);
1081 	case BLKTRACESTART:
1082 		return blk_trace_startstop(sdp->device->request_queue, 1);
1083 	case BLKTRACESTOP:
1084 		return blk_trace_startstop(sdp->device->request_queue, 0);
1085 	case BLKTRACETEARDOWN:
1086 		return blk_trace_remove(sdp->device->request_queue);
1087 	default:
1088 		if (read_only)
1089 			return -EPERM;	/* don't know so take safe approach */
1090 		return scsi_ioctl(sdp->device, cmd_in, p);
1091 	}
1092 }
1093 
1094 static long
1095 sg_unlocked_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1096 {
1097 	int ret;
1098 
1099 	mutex_lock(&sg_mutex);
1100 	ret = sg_ioctl(filp, cmd_in, arg);
1101 	mutex_unlock(&sg_mutex);
1102 
1103 	return ret;
1104 }
1105 
1106 #ifdef CONFIG_COMPAT
1107 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1108 {
1109 	Sg_device *sdp;
1110 	Sg_fd *sfp;
1111 	struct scsi_device *sdev;
1112 
1113 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1114 		return -ENXIO;
1115 
1116 	sdev = sdp->device;
1117 	if (sdev->host->hostt->compat_ioctl) {
1118 		int ret;
1119 
1120 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1121 
1122 		return ret;
1123 	}
1124 
1125 	return -ENOIOCTLCMD;
1126 }
1127 #endif
1128 
1129 static unsigned int
1130 sg_poll(struct file *filp, poll_table * wait)
1131 {
1132 	unsigned int res = 0;
1133 	Sg_device *sdp;
1134 	Sg_fd *sfp;
1135 	Sg_request *srp;
1136 	int count = 0;
1137 	unsigned long iflags;
1138 
1139 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))
1140 	    || sfp->closed)
1141 		return POLLERR;
1142 	poll_wait(filp, &sfp->read_wait, wait);
1143 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1144 	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1145 		/* if any read waiting, flag it */
1146 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1147 			res = POLLIN | POLLRDNORM;
1148 		++count;
1149 	}
1150 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1151 
1152 	if (sdp->detached)
1153 		res |= POLLHUP;
1154 	else if (!sfp->cmd_q) {
1155 		if (0 == count)
1156 			res |= POLLOUT | POLLWRNORM;
1157 	} else if (count < SG_MAX_QUEUE)
1158 		res |= POLLOUT | POLLWRNORM;
1159 	SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
1160 				   sdp->disk->disk_name, (int) res));
1161 	return res;
1162 }
1163 
1164 static int
1165 sg_fasync(int fd, struct file *filp, int mode)
1166 {
1167 	Sg_device *sdp;
1168 	Sg_fd *sfp;
1169 
1170 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1171 		return -ENXIO;
1172 	SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
1173 				   sdp->disk->disk_name, mode));
1174 
1175 	return fasync_helper(fd, filp, mode, &sfp->async_qp);
1176 }
1177 
1178 static int
1179 sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1180 {
1181 	Sg_fd *sfp;
1182 	unsigned long offset, len, sa;
1183 	Sg_scatter_hold *rsv_schp;
1184 	int k, length;
1185 
1186 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1187 		return VM_FAULT_SIGBUS;
1188 	rsv_schp = &sfp->reserve;
1189 	offset = vmf->pgoff << PAGE_SHIFT;
1190 	if (offset >= rsv_schp->bufflen)
1191 		return VM_FAULT_SIGBUS;
1192 	SCSI_LOG_TIMEOUT(3, printk("sg_vma_fault: offset=%lu, scatg=%d\n",
1193 				   offset, rsv_schp->k_use_sg));
1194 	sa = vma->vm_start;
1195 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1196 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1197 		len = vma->vm_end - sa;
1198 		len = (len < length) ? len : length;
1199 		if (offset < len) {
1200 			struct page *page = nth_page(rsv_schp->pages[k],
1201 						     offset >> PAGE_SHIFT);
1202 			get_page(page);	/* increment page count */
1203 			vmf->page = page;
1204 			return 0; /* success */
1205 		}
1206 		sa += len;
1207 		offset -= len;
1208 	}
1209 
1210 	return VM_FAULT_SIGBUS;
1211 }
1212 
1213 static const struct vm_operations_struct sg_mmap_vm_ops = {
1214 	.fault = sg_vma_fault,
1215 };
1216 
1217 static int
1218 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1219 {
1220 	Sg_fd *sfp;
1221 	unsigned long req_sz, len, sa;
1222 	Sg_scatter_hold *rsv_schp;
1223 	int k, length;
1224 
1225 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1226 		return -ENXIO;
1227 	req_sz = vma->vm_end - vma->vm_start;
1228 	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
1229 				   (void *) vma->vm_start, (int) req_sz));
1230 	if (vma->vm_pgoff)
1231 		return -EINVAL;	/* want no offset */
1232 	rsv_schp = &sfp->reserve;
1233 	if (req_sz > rsv_schp->bufflen)
1234 		return -ENOMEM;	/* cannot map more than reserved buffer */
1235 
1236 	sa = vma->vm_start;
1237 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1238 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1239 		len = vma->vm_end - sa;
1240 		len = (len < length) ? len : length;
1241 		sa += len;
1242 	}
1243 
1244 	sfp->mmap_called = 1;
1245 	vma->vm_flags |= VM_RESERVED;
1246 	vma->vm_private_data = sfp;
1247 	vma->vm_ops = &sg_mmap_vm_ops;
1248 	return 0;
1249 }
1250 
1251 static void sg_rq_end_io_usercontext(struct work_struct *work)
1252 {
1253 	struct sg_request *srp = container_of(work, struct sg_request, ew.work);
1254 	struct sg_fd *sfp = srp->parentfp;
1255 
1256 	sg_finish_rem_req(srp);
1257 	kref_put(&sfp->f_ref, sg_remove_sfp);
1258 }
1259 
1260 /*
1261  * This function is a "bottom half" handler that is called by the mid
1262  * level when a command is completed (or has failed).
1263  */
1264 static void sg_rq_end_io(struct request *rq, int uptodate)
1265 {
1266 	struct sg_request *srp = rq->end_io_data;
1267 	Sg_device *sdp;
1268 	Sg_fd *sfp;
1269 	unsigned long iflags;
1270 	unsigned int ms;
1271 	char *sense;
1272 	int result, resid, done = 1;
1273 
1274 	if (WARN_ON(srp->done != 0))
1275 		return;
1276 
1277 	sfp = srp->parentfp;
1278 	if (WARN_ON(sfp == NULL))
1279 		return;
1280 
1281 	sdp = sfp->parentdp;
1282 	if (unlikely(sdp->detached))
1283 		printk(KERN_INFO "sg_rq_end_io: device detached\n");
1284 
1285 	sense = rq->sense;
1286 	result = rq->errors;
1287 	resid = rq->resid_len;
1288 
1289 	SCSI_LOG_TIMEOUT(4, printk("sg_cmd_done: %s, pack_id=%d, res=0x%x\n",
1290 		sdp->disk->disk_name, srp->header.pack_id, result));
1291 	srp->header.resid = resid;
1292 	ms = jiffies_to_msecs(jiffies);
1293 	srp->header.duration = (ms > srp->header.duration) ?
1294 				(ms - srp->header.duration) : 0;
1295 	if (0 != result) {
1296 		struct scsi_sense_hdr sshdr;
1297 
1298 		srp->header.status = 0xff & result;
1299 		srp->header.masked_status = status_byte(result);
1300 		srp->header.msg_status = msg_byte(result);
1301 		srp->header.host_status = host_byte(result);
1302 		srp->header.driver_status = driver_byte(result);
1303 		if ((sdp->sgdebug > 0) &&
1304 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1305 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1306 			__scsi_print_sense("sg_cmd_done", sense,
1307 					   SCSI_SENSE_BUFFERSIZE);
1308 
1309 		/* Following if statement is a patch supplied by Eric Youngdale */
1310 		if (driver_byte(result) != 0
1311 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1312 		    && !scsi_sense_is_deferred(&sshdr)
1313 		    && sshdr.sense_key == UNIT_ATTENTION
1314 		    && sdp->device->removable) {
1315 			/* Detected possible disc change. Set the bit - this */
1316 			/* may be used if there are filesystems using this device */
1317 			sdp->device->changed = 1;
1318 		}
1319 	}
1320 	/* Rely on write phase to clean out srp status values, so no "else" */
1321 
1322 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1323 	if (unlikely(srp->orphan)) {
1324 		if (sfp->keep_orphan)
1325 			srp->sg_io_owned = 0;
1326 		else
1327 			done = 0;
1328 	}
1329 	srp->done = done;
1330 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1331 
1332 	if (likely(done)) {
1333 		/* Now wake up any sg_read() that is waiting for this
1334 		 * packet.
1335 		 */
1336 		wake_up_interruptible(&sfp->read_wait);
1337 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1338 		kref_put(&sfp->f_ref, sg_remove_sfp);
1339 	} else {
1340 		INIT_WORK(&srp->ew.work, sg_rq_end_io_usercontext);
1341 		schedule_work(&srp->ew.work);
1342 	}
1343 }
1344 
1345 static const struct file_operations sg_fops = {
1346 	.owner = THIS_MODULE,
1347 	.read = sg_read,
1348 	.write = sg_write,
1349 	.poll = sg_poll,
1350 	.unlocked_ioctl = sg_unlocked_ioctl,
1351 #ifdef CONFIG_COMPAT
1352 	.compat_ioctl = sg_compat_ioctl,
1353 #endif
1354 	.open = sg_open,
1355 	.mmap = sg_mmap,
1356 	.release = sg_release,
1357 	.fasync = sg_fasync,
1358 	.llseek = no_llseek,
1359 };
1360 
1361 static struct class *sg_sysfs_class;
1362 
1363 static int sg_sysfs_valid = 0;
1364 
1365 static Sg_device *sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1366 {
1367 	struct request_queue *q = scsidp->request_queue;
1368 	Sg_device *sdp;
1369 	unsigned long iflags;
1370 	int error;
1371 	u32 k;
1372 
1373 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1374 	if (!sdp) {
1375 		printk(KERN_WARNING "kmalloc Sg_device failure\n");
1376 		return ERR_PTR(-ENOMEM);
1377 	}
1378 
1379 	if (!idr_pre_get(&sg_index_idr, GFP_KERNEL)) {
1380 		printk(KERN_WARNING "idr expansion Sg_device failure\n");
1381 		error = -ENOMEM;
1382 		goto out;
1383 	}
1384 
1385 	write_lock_irqsave(&sg_index_lock, iflags);
1386 
1387 	error = idr_get_new(&sg_index_idr, sdp, &k);
1388 	if (error) {
1389 		write_unlock_irqrestore(&sg_index_lock, iflags);
1390 		printk(KERN_WARNING "idr allocation Sg_device failure: %d\n",
1391 		       error);
1392 		goto out;
1393 	}
1394 
1395 	if (unlikely(k >= SG_MAX_DEVS))
1396 		goto overflow;
1397 
1398 	SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
1399 	sprintf(disk->disk_name, "sg%d", k);
1400 	disk->first_minor = k;
1401 	sdp->disk = disk;
1402 	sdp->device = scsidp;
1403 	INIT_LIST_HEAD(&sdp->sfds);
1404 	init_waitqueue_head(&sdp->o_excl_wait);
1405 	sdp->sg_tablesize = queue_max_segments(q);
1406 	sdp->index = k;
1407 	kref_init(&sdp->d_ref);
1408 
1409 	write_unlock_irqrestore(&sg_index_lock, iflags);
1410 
1411 	error = 0;
1412  out:
1413 	if (error) {
1414 		kfree(sdp);
1415 		return ERR_PTR(error);
1416 	}
1417 	return sdp;
1418 
1419  overflow:
1420 	idr_remove(&sg_index_idr, k);
1421 	write_unlock_irqrestore(&sg_index_lock, iflags);
1422 	sdev_printk(KERN_WARNING, scsidp,
1423 		    "Unable to attach sg device type=%d, minor "
1424 		    "number exceeds %d\n", scsidp->type, SG_MAX_DEVS - 1);
1425 	error = -ENODEV;
1426 	goto out;
1427 }
1428 
1429 static int
1430 sg_add(struct device *cl_dev, struct class_interface *cl_intf)
1431 {
1432 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1433 	struct gendisk *disk;
1434 	Sg_device *sdp = NULL;
1435 	struct cdev * cdev = NULL;
1436 	int error;
1437 	unsigned long iflags;
1438 
1439 	disk = alloc_disk(1);
1440 	if (!disk) {
1441 		printk(KERN_WARNING "alloc_disk failed\n");
1442 		return -ENOMEM;
1443 	}
1444 	disk->major = SCSI_GENERIC_MAJOR;
1445 
1446 	error = -ENOMEM;
1447 	cdev = cdev_alloc();
1448 	if (!cdev) {
1449 		printk(KERN_WARNING "cdev_alloc failed\n");
1450 		goto out;
1451 	}
1452 	cdev->owner = THIS_MODULE;
1453 	cdev->ops = &sg_fops;
1454 
1455 	sdp = sg_alloc(disk, scsidp);
1456 	if (IS_ERR(sdp)) {
1457 		printk(KERN_WARNING "sg_alloc failed\n");
1458 		error = PTR_ERR(sdp);
1459 		goto out;
1460 	}
1461 
1462 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1463 	if (error)
1464 		goto cdev_add_err;
1465 
1466 	sdp->cdev = cdev;
1467 	if (sg_sysfs_valid) {
1468 		struct device *sg_class_member;
1469 
1470 		sg_class_member = device_create(sg_sysfs_class, cl_dev->parent,
1471 						MKDEV(SCSI_GENERIC_MAJOR,
1472 						      sdp->index),
1473 						sdp, "%s", disk->disk_name);
1474 		if (IS_ERR(sg_class_member)) {
1475 			printk(KERN_ERR "sg_add: "
1476 			       "device_create failed\n");
1477 			error = PTR_ERR(sg_class_member);
1478 			goto cdev_add_err;
1479 		}
1480 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1481 					  &sg_class_member->kobj, "generic");
1482 		if (error)
1483 			printk(KERN_ERR "sg_add: unable to make symlink "
1484 					"'generic' back to sg%d\n", sdp->index);
1485 	} else
1486 		printk(KERN_WARNING "sg_add: sg_sys Invalid\n");
1487 
1488 	sdev_printk(KERN_NOTICE, scsidp,
1489 		    "Attached scsi generic sg%d type %d\n", sdp->index,
1490 		    scsidp->type);
1491 
1492 	dev_set_drvdata(cl_dev, sdp);
1493 
1494 	return 0;
1495 
1496 cdev_add_err:
1497 	write_lock_irqsave(&sg_index_lock, iflags);
1498 	idr_remove(&sg_index_idr, sdp->index);
1499 	write_unlock_irqrestore(&sg_index_lock, iflags);
1500 	kfree(sdp);
1501 
1502 out:
1503 	put_disk(disk);
1504 	if (cdev)
1505 		cdev_del(cdev);
1506 	return error;
1507 }
1508 
1509 static void sg_device_destroy(struct kref *kref)
1510 {
1511 	struct sg_device *sdp = container_of(kref, struct sg_device, d_ref);
1512 	unsigned long flags;
1513 
1514 	/* CAUTION!  Note that the device can still be found via idr_find()
1515 	 * even though the refcount is 0.  Therefore, do idr_remove() BEFORE
1516 	 * any other cleanup.
1517 	 */
1518 
1519 	write_lock_irqsave(&sg_index_lock, flags);
1520 	idr_remove(&sg_index_idr, sdp->index);
1521 	write_unlock_irqrestore(&sg_index_lock, flags);
1522 
1523 	SCSI_LOG_TIMEOUT(3,
1524 		printk("sg_device_destroy: %s\n",
1525 			sdp->disk->disk_name));
1526 
1527 	put_disk(sdp->disk);
1528 	kfree(sdp);
1529 }
1530 
1531 static void sg_remove(struct device *cl_dev, struct class_interface *cl_intf)
1532 {
1533 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1534 	Sg_device *sdp = dev_get_drvdata(cl_dev);
1535 	unsigned long iflags;
1536 	Sg_fd *sfp;
1537 
1538 	if (!sdp || sdp->detached)
1539 		return;
1540 
1541 	SCSI_LOG_TIMEOUT(3, printk("sg_remove: %s\n", sdp->disk->disk_name));
1542 
1543 	/* Need a write lock to set sdp->detached. */
1544 	write_lock_irqsave(&sg_index_lock, iflags);
1545 	sdp->detached = 1;
1546 	list_for_each_entry(sfp, &sdp->sfds, sfd_siblings) {
1547 		wake_up_interruptible(&sfp->read_wait);
1548 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_HUP);
1549 	}
1550 	write_unlock_irqrestore(&sg_index_lock, iflags);
1551 
1552 	sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1553 	device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1554 	cdev_del(sdp->cdev);
1555 	sdp->cdev = NULL;
1556 
1557 	sg_put_dev(sdp);
1558 }
1559 
1560 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1561 module_param_named(def_reserved_size, def_reserved_size, int,
1562 		   S_IRUGO | S_IWUSR);
1563 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1564 
1565 MODULE_AUTHOR("Douglas Gilbert");
1566 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1567 MODULE_LICENSE("GPL");
1568 MODULE_VERSION(SG_VERSION_STR);
1569 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1570 
1571 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1572                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1573 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1574 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1575 
1576 static int __init
1577 init_sg(void)
1578 {
1579 	int rc;
1580 
1581 	if (scatter_elem_sz < PAGE_SIZE) {
1582 		scatter_elem_sz = PAGE_SIZE;
1583 		scatter_elem_sz_prev = scatter_elem_sz;
1584 	}
1585 	if (def_reserved_size >= 0)
1586 		sg_big_buff = def_reserved_size;
1587 	else
1588 		def_reserved_size = sg_big_buff;
1589 
1590 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1591 				    SG_MAX_DEVS, "sg");
1592 	if (rc)
1593 		return rc;
1594         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1595         if ( IS_ERR(sg_sysfs_class) ) {
1596 		rc = PTR_ERR(sg_sysfs_class);
1597 		goto err_out;
1598         }
1599 	sg_sysfs_valid = 1;
1600 	rc = scsi_register_interface(&sg_interface);
1601 	if (0 == rc) {
1602 #ifdef CONFIG_SCSI_PROC_FS
1603 		sg_proc_init();
1604 #endif				/* CONFIG_SCSI_PROC_FS */
1605 		return 0;
1606 	}
1607 	class_destroy(sg_sysfs_class);
1608 err_out:
1609 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1610 	return rc;
1611 }
1612 
1613 static void __exit
1614 exit_sg(void)
1615 {
1616 #ifdef CONFIG_SCSI_PROC_FS
1617 	sg_proc_cleanup();
1618 #endif				/* CONFIG_SCSI_PROC_FS */
1619 	scsi_unregister_interface(&sg_interface);
1620 	class_destroy(sg_sysfs_class);
1621 	sg_sysfs_valid = 0;
1622 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1623 				 SG_MAX_DEVS);
1624 	idr_destroy(&sg_index_idr);
1625 }
1626 
1627 static int sg_start_req(Sg_request *srp, unsigned char *cmd)
1628 {
1629 	int res;
1630 	struct request *rq;
1631 	Sg_fd *sfp = srp->parentfp;
1632 	sg_io_hdr_t *hp = &srp->header;
1633 	int dxfer_len = (int) hp->dxfer_len;
1634 	int dxfer_dir = hp->dxfer_direction;
1635 	unsigned int iov_count = hp->iovec_count;
1636 	Sg_scatter_hold *req_schp = &srp->data;
1637 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1638 	struct request_queue *q = sfp->parentdp->device->request_queue;
1639 	struct rq_map_data *md, map_data;
1640 	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1641 
1642 	SCSI_LOG_TIMEOUT(4, printk(KERN_INFO "sg_start_req: dxfer_len=%d\n",
1643 				   dxfer_len));
1644 
1645 	rq = blk_get_request(q, rw, GFP_ATOMIC);
1646 	if (!rq)
1647 		return -ENOMEM;
1648 
1649 	memcpy(rq->cmd, cmd, hp->cmd_len);
1650 
1651 	rq->cmd_len = hp->cmd_len;
1652 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
1653 
1654 	srp->rq = rq;
1655 	rq->end_io_data = srp;
1656 	rq->sense = srp->sense_b;
1657 	rq->retries = SG_DEFAULT_RETRIES;
1658 
1659 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1660 		return 0;
1661 
1662 	if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1663 	    dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1664 	    !sfp->parentdp->device->host->unchecked_isa_dma &&
1665 	    blk_rq_aligned(q, (unsigned long)hp->dxferp, dxfer_len))
1666 		md = NULL;
1667 	else
1668 		md = &map_data;
1669 
1670 	if (md) {
1671 		if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
1672 			sg_link_reserve(sfp, srp, dxfer_len);
1673 		else {
1674 			res = sg_build_indirect(req_schp, sfp, dxfer_len);
1675 			if (res)
1676 				return res;
1677 		}
1678 
1679 		md->pages = req_schp->pages;
1680 		md->page_order = req_schp->page_order;
1681 		md->nr_entries = req_schp->k_use_sg;
1682 		md->offset = 0;
1683 		md->null_mapped = hp->dxferp ? 0 : 1;
1684 		if (dxfer_dir == SG_DXFER_TO_FROM_DEV)
1685 			md->from_user = 1;
1686 		else
1687 			md->from_user = 0;
1688 	}
1689 
1690 	if (iov_count) {
1691 		int len, size = sizeof(struct sg_iovec) * iov_count;
1692 		struct iovec *iov;
1693 
1694 		iov = memdup_user(hp->dxferp, size);
1695 		if (IS_ERR(iov))
1696 			return PTR_ERR(iov);
1697 
1698 		len = iov_length(iov, iov_count);
1699 		if (hp->dxfer_len < len) {
1700 			iov_count = iov_shorten(iov, iov_count, hp->dxfer_len);
1701 			len = hp->dxfer_len;
1702 		}
1703 
1704 		res = blk_rq_map_user_iov(q, rq, md, (struct sg_iovec *)iov,
1705 					  iov_count,
1706 					  len, GFP_ATOMIC);
1707 		kfree(iov);
1708 	} else
1709 		res = blk_rq_map_user(q, rq, md, hp->dxferp,
1710 				      hp->dxfer_len, GFP_ATOMIC);
1711 
1712 	if (!res) {
1713 		srp->bio = rq->bio;
1714 
1715 		if (!md) {
1716 			req_schp->dio_in_use = 1;
1717 			hp->info |= SG_INFO_DIRECT_IO;
1718 		}
1719 	}
1720 	return res;
1721 }
1722 
1723 static int sg_finish_rem_req(Sg_request * srp)
1724 {
1725 	int ret = 0;
1726 
1727 	Sg_fd *sfp = srp->parentfp;
1728 	Sg_scatter_hold *req_schp = &srp->data;
1729 
1730 	SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
1731 	if (srp->rq) {
1732 		if (srp->bio)
1733 			ret = blk_rq_unmap_user(srp->bio);
1734 
1735 		blk_put_request(srp->rq);
1736 	}
1737 
1738 	if (srp->res_used)
1739 		sg_unlink_reserve(sfp, srp);
1740 	else
1741 		sg_remove_scat(req_schp);
1742 
1743 	sg_remove_request(sfp, srp);
1744 
1745 	return ret;
1746 }
1747 
1748 static int
1749 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1750 {
1751 	int sg_bufflen = tablesize * sizeof(struct page *);
1752 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1753 
1754 	schp->pages = kzalloc(sg_bufflen, gfp_flags);
1755 	if (!schp->pages)
1756 		return -ENOMEM;
1757 	schp->sglist_len = sg_bufflen;
1758 	return tablesize;	/* number of scat_gath elements allocated */
1759 }
1760 
1761 static int
1762 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1763 {
1764 	int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1765 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1766 	int blk_size = buff_size, order;
1767 	gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
1768 
1769 	if (blk_size < 0)
1770 		return -EFAULT;
1771 	if (0 == blk_size)
1772 		++blk_size;	/* don't know why */
1773 	/* round request up to next highest SG_SECTOR_SZ byte boundary */
1774 	blk_size = ALIGN(blk_size, SG_SECTOR_SZ);
1775 	SCSI_LOG_TIMEOUT(4, printk("sg_build_indirect: buff_size=%d, blk_size=%d\n",
1776 				   buff_size, blk_size));
1777 
1778 	/* N.B. ret_sz carried into this block ... */
1779 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1780 	if (mx_sc_elems < 0)
1781 		return mx_sc_elems;	/* most likely -ENOMEM */
1782 
1783 	num = scatter_elem_sz;
1784 	if (unlikely(num != scatter_elem_sz_prev)) {
1785 		if (num < PAGE_SIZE) {
1786 			scatter_elem_sz = PAGE_SIZE;
1787 			scatter_elem_sz_prev = PAGE_SIZE;
1788 		} else
1789 			scatter_elem_sz_prev = num;
1790 	}
1791 
1792 	if (sfp->low_dma)
1793 		gfp_mask |= GFP_DMA;
1794 
1795 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1796 		gfp_mask |= __GFP_ZERO;
1797 
1798 	order = get_order(num);
1799 retry:
1800 	ret_sz = 1 << (PAGE_SHIFT + order);
1801 
1802 	for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1803 	     k++, rem_sz -= ret_sz) {
1804 
1805 		num = (rem_sz > scatter_elem_sz_prev) ?
1806 			scatter_elem_sz_prev : rem_sz;
1807 
1808 		schp->pages[k] = alloc_pages(gfp_mask, order);
1809 		if (!schp->pages[k])
1810 			goto out;
1811 
1812 		if (num == scatter_elem_sz_prev) {
1813 			if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1814 				scatter_elem_sz = ret_sz;
1815 				scatter_elem_sz_prev = ret_sz;
1816 			}
1817 		}
1818 
1819 		SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k=%d, num=%d, "
1820 				 "ret_sz=%d\n", k, num, ret_sz));
1821 	}		/* end of for loop */
1822 
1823 	schp->page_order = order;
1824 	schp->k_use_sg = k;
1825 	SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, "
1826 			 "rem_sz=%d\n", k, rem_sz));
1827 
1828 	schp->bufflen = blk_size;
1829 	if (rem_sz > 0)	/* must have failed */
1830 		return -ENOMEM;
1831 	return 0;
1832 out:
1833 	for (i = 0; i < k; i++)
1834 		__free_pages(schp->pages[i], order);
1835 
1836 	if (--order >= 0)
1837 		goto retry;
1838 
1839 	return -ENOMEM;
1840 }
1841 
1842 static void
1843 sg_remove_scat(Sg_scatter_hold * schp)
1844 {
1845 	SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1846 	if (schp->pages && schp->sglist_len > 0) {
1847 		if (!schp->dio_in_use) {
1848 			int k;
1849 
1850 			for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1851 				SCSI_LOG_TIMEOUT(5, printk(
1852 				    "sg_remove_scat: k=%d, pg=0x%p\n",
1853 				    k, schp->pages[k]));
1854 				__free_pages(schp->pages[k], schp->page_order);
1855 			}
1856 
1857 			kfree(schp->pages);
1858 		}
1859 	}
1860 	memset(schp, 0, sizeof (*schp));
1861 }
1862 
1863 static int
1864 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1865 {
1866 	Sg_scatter_hold *schp = &srp->data;
1867 	int k, num;
1868 
1869 	SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n",
1870 				   num_read_xfer));
1871 	if ((!outp) || (num_read_xfer <= 0))
1872 		return 0;
1873 
1874 	num = 1 << (PAGE_SHIFT + schp->page_order);
1875 	for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1876 		if (num > num_read_xfer) {
1877 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1878 					   num_read_xfer))
1879 				return -EFAULT;
1880 			break;
1881 		} else {
1882 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1883 					   num))
1884 				return -EFAULT;
1885 			num_read_xfer -= num;
1886 			if (num_read_xfer <= 0)
1887 				break;
1888 			outp += num;
1889 		}
1890 	}
1891 
1892 	return 0;
1893 }
1894 
1895 static void
1896 sg_build_reserve(Sg_fd * sfp, int req_size)
1897 {
1898 	Sg_scatter_hold *schp = &sfp->reserve;
1899 
1900 	SCSI_LOG_TIMEOUT(4, printk("sg_build_reserve: req_size=%d\n", req_size));
1901 	do {
1902 		if (req_size < PAGE_SIZE)
1903 			req_size = PAGE_SIZE;
1904 		if (0 == sg_build_indirect(schp, sfp, req_size))
1905 			return;
1906 		else
1907 			sg_remove_scat(schp);
1908 		req_size >>= 1;	/* divide by 2 */
1909 	} while (req_size > (PAGE_SIZE / 2));
1910 }
1911 
1912 static void
1913 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
1914 {
1915 	Sg_scatter_hold *req_schp = &srp->data;
1916 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1917 	int k, num, rem;
1918 
1919 	srp->res_used = 1;
1920 	SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
1921 	rem = size;
1922 
1923 	num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1924 	for (k = 0; k < rsv_schp->k_use_sg; k++) {
1925 		if (rem <= num) {
1926 			req_schp->k_use_sg = k + 1;
1927 			req_schp->sglist_len = rsv_schp->sglist_len;
1928 			req_schp->pages = rsv_schp->pages;
1929 
1930 			req_schp->bufflen = size;
1931 			req_schp->page_order = rsv_schp->page_order;
1932 			break;
1933 		} else
1934 			rem -= num;
1935 	}
1936 
1937 	if (k >= rsv_schp->k_use_sg)
1938 		SCSI_LOG_TIMEOUT(1, printk("sg_link_reserve: BAD size\n"));
1939 }
1940 
1941 static void
1942 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
1943 {
1944 	Sg_scatter_hold *req_schp = &srp->data;
1945 
1946 	SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n",
1947 				   (int) req_schp->k_use_sg));
1948 	req_schp->k_use_sg = 0;
1949 	req_schp->bufflen = 0;
1950 	req_schp->pages = NULL;
1951 	req_schp->page_order = 0;
1952 	req_schp->sglist_len = 0;
1953 	sfp->save_scat_len = 0;
1954 	srp->res_used = 0;
1955 }
1956 
1957 static Sg_request *
1958 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
1959 {
1960 	Sg_request *resp;
1961 	unsigned long iflags;
1962 
1963 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1964 	for (resp = sfp->headrp; resp; resp = resp->nextrp) {
1965 		/* look for requests that are ready + not SG_IO owned */
1966 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
1967 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
1968 			resp->done = 2;	/* guard against other readers */
1969 			break;
1970 		}
1971 	}
1972 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1973 	return resp;
1974 }
1975 
1976 /* always adds to end of list */
1977 static Sg_request *
1978 sg_add_request(Sg_fd * sfp)
1979 {
1980 	int k;
1981 	unsigned long iflags;
1982 	Sg_request *resp;
1983 	Sg_request *rp = sfp->req_arr;
1984 
1985 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1986 	resp = sfp->headrp;
1987 	if (!resp) {
1988 		memset(rp, 0, sizeof (Sg_request));
1989 		rp->parentfp = sfp;
1990 		resp = rp;
1991 		sfp->headrp = resp;
1992 	} else {
1993 		if (0 == sfp->cmd_q)
1994 			resp = NULL;	/* command queuing disallowed */
1995 		else {
1996 			for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
1997 				if (!rp->parentfp)
1998 					break;
1999 			}
2000 			if (k < SG_MAX_QUEUE) {
2001 				memset(rp, 0, sizeof (Sg_request));
2002 				rp->parentfp = sfp;
2003 				while (resp->nextrp)
2004 					resp = resp->nextrp;
2005 				resp->nextrp = rp;
2006 				resp = rp;
2007 			} else
2008 				resp = NULL;
2009 		}
2010 	}
2011 	if (resp) {
2012 		resp->nextrp = NULL;
2013 		resp->header.duration = jiffies_to_msecs(jiffies);
2014 	}
2015 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2016 	return resp;
2017 }
2018 
2019 /* Return of 1 for found; 0 for not found */
2020 static int
2021 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2022 {
2023 	Sg_request *prev_rp;
2024 	Sg_request *rp;
2025 	unsigned long iflags;
2026 	int res = 0;
2027 
2028 	if ((!sfp) || (!srp) || (!sfp->headrp))
2029 		return res;
2030 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2031 	prev_rp = sfp->headrp;
2032 	if (srp == prev_rp) {
2033 		sfp->headrp = prev_rp->nextrp;
2034 		prev_rp->parentfp = NULL;
2035 		res = 1;
2036 	} else {
2037 		while ((rp = prev_rp->nextrp)) {
2038 			if (srp == rp) {
2039 				prev_rp->nextrp = rp->nextrp;
2040 				rp->parentfp = NULL;
2041 				res = 1;
2042 				break;
2043 			}
2044 			prev_rp = rp;
2045 		}
2046 	}
2047 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2048 	return res;
2049 }
2050 
2051 static Sg_fd *
2052 sg_add_sfp(Sg_device * sdp, int dev)
2053 {
2054 	Sg_fd *sfp;
2055 	unsigned long iflags;
2056 	int bufflen;
2057 
2058 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2059 	if (!sfp)
2060 		return NULL;
2061 
2062 	init_waitqueue_head(&sfp->read_wait);
2063 	rwlock_init(&sfp->rq_list_lock);
2064 
2065 	kref_init(&sfp->f_ref);
2066 	sfp->timeout = SG_DEFAULT_TIMEOUT;
2067 	sfp->timeout_user = SG_DEFAULT_TIMEOUT_USER;
2068 	sfp->force_packid = SG_DEF_FORCE_PACK_ID;
2069 	sfp->low_dma = (SG_DEF_FORCE_LOW_DMA == 0) ?
2070 	    sdp->device->host->unchecked_isa_dma : 1;
2071 	sfp->cmd_q = SG_DEF_COMMAND_Q;
2072 	sfp->keep_orphan = SG_DEF_KEEP_ORPHAN;
2073 	sfp->parentdp = sdp;
2074 	write_lock_irqsave(&sg_index_lock, iflags);
2075 	list_add_tail(&sfp->sfd_siblings, &sdp->sfds);
2076 	write_unlock_irqrestore(&sg_index_lock, iflags);
2077 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
2078 	if (unlikely(sg_big_buff != def_reserved_size))
2079 		sg_big_buff = def_reserved_size;
2080 
2081 	bufflen = min_t(int, sg_big_buff,
2082 			queue_max_sectors(sdp->device->request_queue) * 512);
2083 	sg_build_reserve(sfp, bufflen);
2084 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp:   bufflen=%d, k_use_sg=%d\n",
2085 			   sfp->reserve.bufflen, sfp->reserve.k_use_sg));
2086 
2087 	kref_get(&sdp->d_ref);
2088 	__module_get(THIS_MODULE);
2089 	return sfp;
2090 }
2091 
2092 static void sg_remove_sfp_usercontext(struct work_struct *work)
2093 {
2094 	struct sg_fd *sfp = container_of(work, struct sg_fd, ew.work);
2095 	struct sg_device *sdp = sfp->parentdp;
2096 
2097 	/* Cleanup any responses which were never read(). */
2098 	while (sfp->headrp)
2099 		sg_finish_rem_req(sfp->headrp);
2100 
2101 	if (sfp->reserve.bufflen > 0) {
2102 		SCSI_LOG_TIMEOUT(6,
2103 			printk("sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2104 				(int) sfp->reserve.bufflen,
2105 				(int) sfp->reserve.k_use_sg));
2106 		sg_remove_scat(&sfp->reserve);
2107 	}
2108 
2109 	SCSI_LOG_TIMEOUT(6,
2110 		printk("sg_remove_sfp: %s, sfp=0x%p\n",
2111 			sdp->disk->disk_name,
2112 			sfp));
2113 	kfree(sfp);
2114 
2115 	scsi_device_put(sdp->device);
2116 	sg_put_dev(sdp);
2117 	module_put(THIS_MODULE);
2118 }
2119 
2120 static void sg_remove_sfp(struct kref *kref)
2121 {
2122 	struct sg_fd *sfp = container_of(kref, struct sg_fd, f_ref);
2123 	struct sg_device *sdp = sfp->parentdp;
2124 	unsigned long iflags;
2125 
2126 	write_lock_irqsave(&sg_index_lock, iflags);
2127 	list_del(&sfp->sfd_siblings);
2128 	write_unlock_irqrestore(&sg_index_lock, iflags);
2129 	wake_up_interruptible(&sdp->o_excl_wait);
2130 
2131 	INIT_WORK(&sfp->ew.work, sg_remove_sfp_usercontext);
2132 	schedule_work(&sfp->ew.work);
2133 }
2134 
2135 static int
2136 sg_res_in_use(Sg_fd * sfp)
2137 {
2138 	const Sg_request *srp;
2139 	unsigned long iflags;
2140 
2141 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2142 	for (srp = sfp->headrp; srp; srp = srp->nextrp)
2143 		if (srp->res_used)
2144 			break;
2145 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2146 	return srp ? 1 : 0;
2147 }
2148 
2149 #ifdef CONFIG_SCSI_PROC_FS
2150 static int
2151 sg_idr_max_id(int id, void *p, void *data)
2152 {
2153 	int *k = data;
2154 
2155 	if (*k < id)
2156 		*k = id;
2157 
2158 	return 0;
2159 }
2160 
2161 static int
2162 sg_last_dev(void)
2163 {
2164 	int k = -1;
2165 	unsigned long iflags;
2166 
2167 	read_lock_irqsave(&sg_index_lock, iflags);
2168 	idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2169 	read_unlock_irqrestore(&sg_index_lock, iflags);
2170 	return k + 1;		/* origin 1 */
2171 }
2172 #endif
2173 
2174 /* must be called with sg_index_lock held */
2175 static Sg_device *sg_lookup_dev(int dev)
2176 {
2177 	return idr_find(&sg_index_idr, dev);
2178 }
2179 
2180 static Sg_device *sg_get_dev(int dev)
2181 {
2182 	struct sg_device *sdp;
2183 	unsigned long flags;
2184 
2185 	read_lock_irqsave(&sg_index_lock, flags);
2186 	sdp = sg_lookup_dev(dev);
2187 	if (!sdp)
2188 		sdp = ERR_PTR(-ENXIO);
2189 	else if (sdp->detached) {
2190 		/* If sdp->detached, then the refcount may already be 0, in
2191 		 * which case it would be a bug to do kref_get().
2192 		 */
2193 		sdp = ERR_PTR(-ENODEV);
2194 	} else
2195 		kref_get(&sdp->d_ref);
2196 	read_unlock_irqrestore(&sg_index_lock, flags);
2197 
2198 	return sdp;
2199 }
2200 
2201 static void sg_put_dev(struct sg_device *sdp)
2202 {
2203 	kref_put(&sdp->d_ref, sg_device_destroy);
2204 }
2205 
2206 #ifdef CONFIG_SCSI_PROC_FS
2207 
2208 static struct proc_dir_entry *sg_proc_sgp = NULL;
2209 
2210 static char sg_proc_sg_dirname[] = "scsi/sg";
2211 
2212 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2213 
2214 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2215 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2216 			          size_t count, loff_t *off);
2217 static const struct file_operations adio_fops = {
2218 	.owner = THIS_MODULE,
2219 	.open = sg_proc_single_open_adio,
2220 	.read = seq_read,
2221 	.llseek = seq_lseek,
2222 	.write = sg_proc_write_adio,
2223 	.release = single_release,
2224 };
2225 
2226 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2227 static ssize_t sg_proc_write_dressz(struct file *filp,
2228 		const char __user *buffer, size_t count, loff_t *off);
2229 static const struct file_operations dressz_fops = {
2230 	.owner = THIS_MODULE,
2231 	.open = sg_proc_single_open_dressz,
2232 	.read = seq_read,
2233 	.llseek = seq_lseek,
2234 	.write = sg_proc_write_dressz,
2235 	.release = single_release,
2236 };
2237 
2238 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2239 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2240 static const struct file_operations version_fops = {
2241 	.owner = THIS_MODULE,
2242 	.open = sg_proc_single_open_version,
2243 	.read = seq_read,
2244 	.llseek = seq_lseek,
2245 	.release = single_release,
2246 };
2247 
2248 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2249 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2250 static const struct file_operations devhdr_fops = {
2251 	.owner = THIS_MODULE,
2252 	.open = sg_proc_single_open_devhdr,
2253 	.read = seq_read,
2254 	.llseek = seq_lseek,
2255 	.release = single_release,
2256 };
2257 
2258 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2259 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2260 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2261 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2262 static void dev_seq_stop(struct seq_file *s, void *v);
2263 static const struct file_operations dev_fops = {
2264 	.owner = THIS_MODULE,
2265 	.open = sg_proc_open_dev,
2266 	.read = seq_read,
2267 	.llseek = seq_lseek,
2268 	.release = seq_release,
2269 };
2270 static const struct seq_operations dev_seq_ops = {
2271 	.start = dev_seq_start,
2272 	.next  = dev_seq_next,
2273 	.stop  = dev_seq_stop,
2274 	.show  = sg_proc_seq_show_dev,
2275 };
2276 
2277 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2278 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2279 static const struct file_operations devstrs_fops = {
2280 	.owner = THIS_MODULE,
2281 	.open = sg_proc_open_devstrs,
2282 	.read = seq_read,
2283 	.llseek = seq_lseek,
2284 	.release = seq_release,
2285 };
2286 static const struct seq_operations devstrs_seq_ops = {
2287 	.start = dev_seq_start,
2288 	.next  = dev_seq_next,
2289 	.stop  = dev_seq_stop,
2290 	.show  = sg_proc_seq_show_devstrs,
2291 };
2292 
2293 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2294 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2295 static const struct file_operations debug_fops = {
2296 	.owner = THIS_MODULE,
2297 	.open = sg_proc_open_debug,
2298 	.read = seq_read,
2299 	.llseek = seq_lseek,
2300 	.release = seq_release,
2301 };
2302 static const struct seq_operations debug_seq_ops = {
2303 	.start = dev_seq_start,
2304 	.next  = dev_seq_next,
2305 	.stop  = dev_seq_stop,
2306 	.show  = sg_proc_seq_show_debug,
2307 };
2308 
2309 
2310 struct sg_proc_leaf {
2311 	const char * name;
2312 	const struct file_operations * fops;
2313 };
2314 
2315 static struct sg_proc_leaf sg_proc_leaf_arr[] = {
2316 	{"allow_dio", &adio_fops},
2317 	{"debug", &debug_fops},
2318 	{"def_reserved_size", &dressz_fops},
2319 	{"device_hdr", &devhdr_fops},
2320 	{"devices", &dev_fops},
2321 	{"device_strs", &devstrs_fops},
2322 	{"version", &version_fops}
2323 };
2324 
2325 static int
2326 sg_proc_init(void)
2327 {
2328 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2329 	int k;
2330 
2331 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2332 	if (!sg_proc_sgp)
2333 		return 1;
2334 	for (k = 0; k < num_leaves; ++k) {
2335 		struct sg_proc_leaf *leaf = &sg_proc_leaf_arr[k];
2336 		umode_t mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2337 		proc_create(leaf->name, mask, sg_proc_sgp, leaf->fops);
2338 	}
2339 	return 0;
2340 }
2341 
2342 static void
2343 sg_proc_cleanup(void)
2344 {
2345 	int k;
2346 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2347 
2348 	if (!sg_proc_sgp)
2349 		return;
2350 	for (k = 0; k < num_leaves; ++k)
2351 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2352 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2353 }
2354 
2355 
2356 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2357 {
2358 	seq_printf(s, "%d\n", *((int *)s->private));
2359 	return 0;
2360 }
2361 
2362 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2363 {
2364 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2365 }
2366 
2367 static ssize_t
2368 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2369 		   size_t count, loff_t *off)
2370 {
2371 	int err;
2372 	unsigned long num;
2373 
2374 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2375 		return -EACCES;
2376 	err = kstrtoul_from_user(buffer, count, 0, &num);
2377 	if (err)
2378 		return err;
2379 	sg_allow_dio = num ? 1 : 0;
2380 	return count;
2381 }
2382 
2383 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2384 {
2385 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2386 }
2387 
2388 static ssize_t
2389 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2390 		     size_t count, loff_t *off)
2391 {
2392 	int err;
2393 	unsigned long k = ULONG_MAX;
2394 
2395 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2396 		return -EACCES;
2397 
2398 	err = kstrtoul_from_user(buffer, count, 0, &k);
2399 	if (err)
2400 		return err;
2401 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2402 		sg_big_buff = k;
2403 		return count;
2404 	}
2405 	return -ERANGE;
2406 }
2407 
2408 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2409 {
2410 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2411 		   sg_version_date);
2412 	return 0;
2413 }
2414 
2415 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2416 {
2417 	return single_open(file, sg_proc_seq_show_version, NULL);
2418 }
2419 
2420 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2421 {
2422 	seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
2423 		   "online\n");
2424 	return 0;
2425 }
2426 
2427 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2428 {
2429 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2430 }
2431 
2432 struct sg_proc_deviter {
2433 	loff_t	index;
2434 	size_t	max;
2435 };
2436 
2437 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2438 {
2439 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2440 
2441 	s->private = it;
2442 	if (! it)
2443 		return NULL;
2444 
2445 	it->index = *pos;
2446 	it->max = sg_last_dev();
2447 	if (it->index >= it->max)
2448 		return NULL;
2449 	return it;
2450 }
2451 
2452 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2453 {
2454 	struct sg_proc_deviter * it = s->private;
2455 
2456 	*pos = ++it->index;
2457 	return (it->index < it->max) ? it : NULL;
2458 }
2459 
2460 static void dev_seq_stop(struct seq_file *s, void *v)
2461 {
2462 	kfree(s->private);
2463 }
2464 
2465 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2466 {
2467         return seq_open(file, &dev_seq_ops);
2468 }
2469 
2470 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2471 {
2472 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2473 	Sg_device *sdp;
2474 	struct scsi_device *scsidp;
2475 	unsigned long iflags;
2476 
2477 	read_lock_irqsave(&sg_index_lock, iflags);
2478 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2479 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2480 		seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
2481 			      scsidp->host->host_no, scsidp->channel,
2482 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2483 			      1,
2484 			      (int) scsidp->queue_depth,
2485 			      (int) scsidp->device_busy,
2486 			      (int) scsi_device_online(scsidp));
2487 	else
2488 		seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2489 	read_unlock_irqrestore(&sg_index_lock, iflags);
2490 	return 0;
2491 }
2492 
2493 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2494 {
2495         return seq_open(file, &devstrs_seq_ops);
2496 }
2497 
2498 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2499 {
2500 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2501 	Sg_device *sdp;
2502 	struct scsi_device *scsidp;
2503 	unsigned long iflags;
2504 
2505 	read_lock_irqsave(&sg_index_lock, iflags);
2506 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2507 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2508 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2509 			   scsidp->vendor, scsidp->model, scsidp->rev);
2510 	else
2511 		seq_printf(s, "<no active device>\n");
2512 	read_unlock_irqrestore(&sg_index_lock, iflags);
2513 	return 0;
2514 }
2515 
2516 /* must be called while holding sg_index_lock */
2517 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2518 {
2519 	int k, m, new_interface, blen, usg;
2520 	Sg_request *srp;
2521 	Sg_fd *fp;
2522 	const sg_io_hdr_t *hp;
2523 	const char * cp;
2524 	unsigned int ms;
2525 
2526 	k = 0;
2527 	list_for_each_entry(fp, &sdp->sfds, sfd_siblings) {
2528 		k++;
2529 		read_lock(&fp->rq_list_lock); /* irqs already disabled */
2530 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2531 			   "(res)sgat=%d low_dma=%d\n", k,
2532 			   jiffies_to_msecs(fp->timeout),
2533 			   fp->reserve.bufflen,
2534 			   (int) fp->reserve.k_use_sg,
2535 			   (int) fp->low_dma);
2536 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=%d\n",
2537 			   (int) fp->cmd_q, (int) fp->force_packid,
2538 			   (int) fp->keep_orphan, (int) fp->closed);
2539 		for (m = 0, srp = fp->headrp;
2540 				srp != NULL;
2541 				++m, srp = srp->nextrp) {
2542 			hp = &srp->header;
2543 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2544 			if (srp->res_used) {
2545 				if (new_interface &&
2546 				    (SG_FLAG_MMAP_IO & hp->flags))
2547 					cp = "     mmap>> ";
2548 				else
2549 					cp = "     rb>> ";
2550 			} else {
2551 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2552 					cp = "     dio>> ";
2553 				else
2554 					cp = "     ";
2555 			}
2556 			seq_printf(s, cp);
2557 			blen = srp->data.bufflen;
2558 			usg = srp->data.k_use_sg;
2559 			seq_printf(s, srp->done ?
2560 				   ((1 == srp->done) ?  "rcv:" : "fin:")
2561 				   : "act:");
2562 			seq_printf(s, " id=%d blen=%d",
2563 				   srp->header.pack_id, blen);
2564 			if (srp->done)
2565 				seq_printf(s, " dur=%d", hp->duration);
2566 			else {
2567 				ms = jiffies_to_msecs(jiffies);
2568 				seq_printf(s, " t_o/elap=%d/%d",
2569 					(new_interface ? hp->timeout :
2570 						  jiffies_to_msecs(fp->timeout)),
2571 					(ms > hp->duration ? ms - hp->duration : 0));
2572 			}
2573 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2574 				   (int) srp->data.cmd_opcode);
2575 		}
2576 		if (0 == m)
2577 			seq_printf(s, "     No requests active\n");
2578 		read_unlock(&fp->rq_list_lock);
2579 	}
2580 }
2581 
2582 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2583 {
2584         return seq_open(file, &debug_seq_ops);
2585 }
2586 
2587 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2588 {
2589 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2590 	Sg_device *sdp;
2591 	unsigned long iflags;
2592 
2593 	if (it && (0 == it->index)) {
2594 		seq_printf(s, "max_active_device=%d(origin 1)\n",
2595 			   (int)it->max);
2596 		seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
2597 	}
2598 
2599 	read_lock_irqsave(&sg_index_lock, iflags);
2600 	sdp = it ? sg_lookup_dev(it->index) : NULL;
2601 	if (sdp && !list_empty(&sdp->sfds)) {
2602 		struct scsi_device *scsidp = sdp->device;
2603 
2604 		seq_printf(s, " >>> device=%s ", sdp->disk->disk_name);
2605 		if (sdp->detached)
2606 			seq_printf(s, "detached pending close ");
2607 		else
2608 			seq_printf
2609 			    (s, "scsi%d chan=%d id=%d lun=%d   em=%d",
2610 			     scsidp->host->host_no,
2611 			     scsidp->channel, scsidp->id,
2612 			     scsidp->lun,
2613 			     scsidp->host->hostt->emulated);
2614 		seq_printf(s, " sg_tablesize=%d excl=%d\n",
2615 			   sdp->sg_tablesize, sdp->exclude);
2616 		sg_proc_debug_helper(s, sdp);
2617 	}
2618 	read_unlock_irqrestore(&sg_index_lock, iflags);
2619 	return 0;
2620 }
2621 
2622 #endif				/* CONFIG_SCSI_PROC_FS */
2623 
2624 module_init(init_sg);
2625 module_exit(exit_sg);
2626