xref: /openbmc/linux/drivers/scsi/sg.c (revision 384740dc)
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/fcntl.h>
42 #include <linux/init.h>
43 #include <linux/poll.h>
44 #include <linux/moduleparam.h>
45 #include <linux/cdev.h>
46 #include <linux/idr.h>
47 #include <linux/seq_file.h>
48 #include <linux/blkdev.h>
49 #include <linux/delay.h>
50 #include <linux/blktrace_api.h>
51 #include <linux/smp_lock.h>
52 
53 #include "scsi.h"
54 #include <scsi/scsi_dbg.h>
55 #include <scsi/scsi_host.h>
56 #include <scsi/scsi_driver.h>
57 #include <scsi/scsi_ioctl.h>
58 #include <scsi/sg.h>
59 
60 #include "scsi_logging.h"
61 
62 #ifdef CONFIG_SCSI_PROC_FS
63 #include <linux/proc_fs.h>
64 static char *sg_version_date = "20061027";
65 
66 static int sg_proc_init(void);
67 static void sg_proc_cleanup(void);
68 #endif
69 
70 #define SG_ALLOW_DIO_DEF 0
71 
72 #define SG_MAX_DEVS 32768
73 
74 /*
75  * Suppose you want to calculate the formula muldiv(x,m,d)=int(x * m / d)
76  * Then when using 32 bit integers x * m may overflow during the calculation.
77  * Replacing muldiv(x) by muldiv(x)=((x % d) * m) / d + int(x / d) * m
78  * calculates the same, but prevents the overflow when both m and d
79  * are "small" numbers (like HZ and USER_HZ).
80  * Of course an overflow is inavoidable if the result of muldiv doesn't fit
81  * in 32 bits.
82  */
83 #define MULDIV(X,MUL,DIV) ((((X % DIV) * MUL) / DIV) + ((X / DIV) * MUL))
84 
85 #define SG_DEFAULT_TIMEOUT MULDIV(SG_DEFAULT_TIMEOUT_USER, HZ, USER_HZ)
86 
87 int sg_big_buff = SG_DEF_RESERVED_SIZE;
88 /* N.B. This variable is readable and writeable via
89    /proc/scsi/sg/def_reserved_size . Each time sg_open() is called a buffer
90    of this size (or less if there is not enough memory) will be reserved
91    for use by this file descriptor. [Deprecated usage: this variable is also
92    readable via /proc/sys/kernel/sg-big-buff if the sg driver is built into
93    the kernel (i.e. it is not a module).] */
94 static int def_reserved_size = -1;	/* picks up init parameter */
95 static int sg_allow_dio = SG_ALLOW_DIO_DEF;
96 
97 static int scatter_elem_sz = SG_SCATTER_SZ;
98 static int scatter_elem_sz_prev = SG_SCATTER_SZ;
99 
100 #define SG_SECTOR_SZ 512
101 #define SG_SECTOR_MSK (SG_SECTOR_SZ - 1)
102 
103 static int sg_add(struct device *, struct class_interface *);
104 static void sg_remove(struct device *, struct class_interface *);
105 
106 static DEFINE_IDR(sg_index_idr);
107 static DEFINE_RWLOCK(sg_index_lock);	/* Also used to lock
108 							   file descriptor list for device */
109 
110 static struct class_interface sg_interface = {
111 	.add_dev	= sg_add,
112 	.remove_dev	= sg_remove,
113 };
114 
115 typedef struct sg_scatter_hold { /* holding area for scsi scatter gather info */
116 	unsigned short k_use_sg; /* Count of kernel scatter-gather pieces */
117 	unsigned sglist_len; /* size of malloc'd scatter-gather list ++ */
118 	unsigned bufflen;	/* Size of (aggregate) data buffer */
119 	struct page **pages;
120 	int page_order;
121 	char dio_in_use;	/* 0->indirect IO (or mmap), 1->dio */
122 	unsigned char cmd_opcode; /* first byte of command */
123 } Sg_scatter_hold;
124 
125 struct sg_device;		/* forward declarations */
126 struct sg_fd;
127 
128 typedef struct sg_request {	/* SG_MAX_QUEUE requests outstanding per file */
129 	struct sg_request *nextrp;	/* NULL -> tail request (slist) */
130 	struct sg_fd *parentfp;	/* NULL -> not in use */
131 	Sg_scatter_hold data;	/* hold buffer, perhaps scatter list */
132 	sg_io_hdr_t header;	/* scsi command+info, see <scsi/sg.h> */
133 	unsigned char sense_b[SCSI_SENSE_BUFFERSIZE];
134 	char res_used;		/* 1 -> using reserve buffer, 0 -> not ... */
135 	char orphan;		/* 1 -> drop on sight, 0 -> normal */
136 	char sg_io_owned;	/* 1 -> packet belongs to SG_IO */
137 	volatile char done;	/* 0->before bh, 1->before read, 2->read */
138 	struct request *rq;
139 	struct bio *bio;
140 } Sg_request;
141 
142 typedef struct sg_fd {		/* holds the state of a file descriptor */
143 	struct sg_fd *nextfp;	/* NULL when last opened fd on this device */
144 	struct sg_device *parentdp;	/* owning device */
145 	wait_queue_head_t read_wait;	/* queue read until command done */
146 	rwlock_t rq_list_lock;	/* protect access to list in req_arr */
147 	int timeout;		/* defaults to SG_DEFAULT_TIMEOUT      */
148 	int timeout_user;	/* defaults to SG_DEFAULT_TIMEOUT_USER */
149 	Sg_scatter_hold reserve;	/* buffer held for this file descriptor */
150 	unsigned save_scat_len;	/* original length of trunc. scat. element */
151 	Sg_request *headrp;	/* head of request slist, NULL->empty */
152 	struct fasync_struct *async_qp;	/* used by asynchronous notification */
153 	Sg_request req_arr[SG_MAX_QUEUE];	/* used as singly-linked list */
154 	char low_dma;		/* as in parent but possibly overridden to 1 */
155 	char force_packid;	/* 1 -> pack_id input to read(), 0 -> ignored */
156 	volatile char closed;	/* 1 -> fd closed but request(s) outstanding */
157 	char cmd_q;		/* 1 -> allow command queuing, 0 -> don't */
158 	char next_cmd_len;	/* 0 -> automatic (def), >0 -> use on next write() */
159 	char keep_orphan;	/* 0 -> drop orphan (def), 1 -> keep for read() */
160 	char mmap_called;	/* 0 -> mmap() never called on this fd */
161 } Sg_fd;
162 
163 typedef struct sg_device { /* holds the state of each scsi generic device */
164 	struct scsi_device *device;
165 	wait_queue_head_t o_excl_wait;	/* queue open() when O_EXCL in use */
166 	int sg_tablesize;	/* adapter's max scatter-gather table size */
167 	u32 index;		/* device index number */
168 	Sg_fd *headfp;		/* first open fd belonging to this device */
169 	volatile char detached;	/* 0->attached, 1->detached pending removal */
170 	volatile char exclude;	/* opened for exclusive access */
171 	char sgdebug;		/* 0->off, 1->sense, 9->dump dev, 10-> all devs */
172 	struct gendisk *disk;
173 	struct cdev * cdev;	/* char_dev [sysfs: /sys/cdev/major/sg<n>] */
174 } Sg_device;
175 
176 static int sg_fasync(int fd, struct file *filp, int mode);
177 /* tasklet or soft irq callback */
178 static void sg_rq_end_io(struct request *rq, int uptodate);
179 static int sg_start_req(Sg_request *srp, unsigned char *cmd);
180 static void sg_finish_rem_req(Sg_request * srp);
181 static int sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size);
182 static int sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp,
183 			 int tablesize);
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, 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_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, int dev);
197 static int sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
198 static void __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp);
199 static Sg_request *sg_get_rq_mark(Sg_fd * sfp, int pack_id);
200 static Sg_request *sg_add_request(Sg_fd * sfp);
201 static int sg_remove_request(Sg_fd * sfp, Sg_request * srp);
202 static int sg_res_in_use(Sg_fd * sfp);
203 static Sg_device *sg_get_dev(int dev);
204 #ifdef CONFIG_SCSI_PROC_FS
205 static int sg_last_dev(void);
206 #endif
207 
208 #define SZ_SG_HEADER sizeof(struct sg_header)
209 #define SZ_SG_IO_HDR sizeof(sg_io_hdr_t)
210 #define SZ_SG_IOVEC sizeof(sg_iovec_t)
211 #define SZ_SG_REQ_INFO sizeof(sg_req_info_t)
212 
213 static int sg_allow_access(struct file *filp, unsigned char *cmd)
214 {
215 	struct sg_fd *sfp = (struct sg_fd *)filp->private_data;
216 	struct request_queue *q = sfp->parentdp->device->request_queue;
217 
218 	if (sfp->parentdp->device->type == TYPE_SCANNER)
219 		return 0;
220 
221 	return blk_verify_command(&q->cmd_filter,
222 				  cmd, filp->f_mode & FMODE_WRITE);
223 }
224 
225 static int
226 sg_open(struct inode *inode, struct file *filp)
227 {
228 	int dev = iminor(inode);
229 	int flags = filp->f_flags;
230 	struct request_queue *q;
231 	Sg_device *sdp;
232 	Sg_fd *sfp;
233 	int res;
234 	int retval;
235 
236 	lock_kernel();
237 	nonseekable_open(inode, filp);
238 	SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
239 	sdp = sg_get_dev(dev);
240 	if ((!sdp) || (!sdp->device)) {
241 		unlock_kernel();
242 		return -ENXIO;
243 	}
244 	if (sdp->detached) {
245 		unlock_kernel();
246 		return -ENODEV;
247 	}
248 
249 	/* This driver's module count bumped by fops_get in <linux/fs.h> */
250 	/* Prevent the device driver from vanishing while we sleep */
251 	retval = scsi_device_get(sdp->device);
252 	if (retval) {
253 		unlock_kernel();
254 		return retval;
255 	}
256 
257 	if (!((flags & O_NONBLOCK) ||
258 	      scsi_block_when_processing_errors(sdp->device))) {
259 		retval = -ENXIO;
260 		/* we are in error recovery for this device */
261 		goto error_out;
262 	}
263 
264 	if (flags & O_EXCL) {
265 		if (O_RDONLY == (flags & O_ACCMODE)) {
266 			retval = -EPERM; /* Can't lock it with read only access */
267 			goto error_out;
268 		}
269 		if (sdp->headfp && (flags & O_NONBLOCK)) {
270 			retval = -EBUSY;
271 			goto error_out;
272 		}
273 		res = 0;
274 		__wait_event_interruptible(sdp->o_excl_wait,
275 			((sdp->headfp || sdp->exclude) ? 0 : (sdp->exclude = 1)), res);
276 		if (res) {
277 			retval = res;	/* -ERESTARTSYS because signal hit process */
278 			goto error_out;
279 		}
280 	} else if (sdp->exclude) {	/* some other fd has an exclusive lock on dev */
281 		if (flags & O_NONBLOCK) {
282 			retval = -EBUSY;
283 			goto error_out;
284 		}
285 		res = 0;
286 		__wait_event_interruptible(sdp->o_excl_wait, (!sdp->exclude),
287 					   res);
288 		if (res) {
289 			retval = res;	/* -ERESTARTSYS because signal hit process */
290 			goto error_out;
291 		}
292 	}
293 	if (sdp->detached) {
294 		retval = -ENODEV;
295 		goto error_out;
296 	}
297 	if (!sdp->headfp) {	/* no existing opens on this device */
298 		sdp->sgdebug = 0;
299 		q = sdp->device->request_queue;
300 		sdp->sg_tablesize = min(q->max_hw_segments,
301 					q->max_phys_segments);
302 	}
303 	if ((sfp = sg_add_sfp(sdp, dev)))
304 		filp->private_data = sfp;
305 	else {
306 		if (flags & O_EXCL)
307 			sdp->exclude = 0;	/* undo if error */
308 		retval = -ENOMEM;
309 		goto error_out;
310 	}
311 	unlock_kernel();
312 	return 0;
313 
314       error_out:
315 	scsi_device_put(sdp->device);
316 	unlock_kernel();
317 	return retval;
318 }
319 
320 /* Following function was formerly called 'sg_close' */
321 static int
322 sg_release(struct inode *inode, struct file *filp)
323 {
324 	Sg_device *sdp;
325 	Sg_fd *sfp;
326 
327 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
328 		return -ENXIO;
329 	SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
330 	sg_fasync(-1, filp, 0);	/* remove filp from async notification list */
331 	if (0 == sg_remove_sfp(sdp, sfp)) {	/* Returns 1 when sdp gone */
332 		if (!sdp->detached) {
333 			scsi_device_put(sdp->device);
334 		}
335 		sdp->exclude = 0;
336 		wake_up_interruptible(&sdp->o_excl_wait);
337 	}
338 	return 0;
339 }
340 
341 static ssize_t
342 sg_read(struct file *filp, char __user *buf, size_t count, loff_t * ppos)
343 {
344 	Sg_device *sdp;
345 	Sg_fd *sfp;
346 	Sg_request *srp;
347 	int req_pack_id = -1;
348 	sg_io_hdr_t *hp;
349 	struct sg_header *old_hdr = NULL;
350 	int retval = 0;
351 
352 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
353 		return -ENXIO;
354 	SCSI_LOG_TIMEOUT(3, printk("sg_read: %s, count=%d\n",
355 				   sdp->disk->disk_name, (int) count));
356 
357 	if (!access_ok(VERIFY_WRITE, buf, count))
358 		return -EFAULT;
359 	if (sfp->force_packid && (count >= SZ_SG_HEADER)) {
360 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
361 		if (!old_hdr)
362 			return -ENOMEM;
363 		if (__copy_from_user(old_hdr, buf, SZ_SG_HEADER)) {
364 			retval = -EFAULT;
365 			goto free_old_hdr;
366 		}
367 		if (old_hdr->reply_len < 0) {
368 			if (count >= SZ_SG_IO_HDR) {
369 				sg_io_hdr_t *new_hdr;
370 				new_hdr = kmalloc(SZ_SG_IO_HDR, GFP_KERNEL);
371 				if (!new_hdr) {
372 					retval = -ENOMEM;
373 					goto free_old_hdr;
374 				}
375 				retval =__copy_from_user
376 				    (new_hdr, buf, SZ_SG_IO_HDR);
377 				req_pack_id = new_hdr->pack_id;
378 				kfree(new_hdr);
379 				if (retval) {
380 					retval = -EFAULT;
381 					goto free_old_hdr;
382 				}
383 			}
384 		} else
385 			req_pack_id = old_hdr->pack_id;
386 	}
387 	srp = sg_get_rq_mark(sfp, req_pack_id);
388 	if (!srp) {		/* now wait on packet to arrive */
389 		if (sdp->detached) {
390 			retval = -ENODEV;
391 			goto free_old_hdr;
392 		}
393 		if (filp->f_flags & O_NONBLOCK) {
394 			retval = -EAGAIN;
395 			goto free_old_hdr;
396 		}
397 		while (1) {
398 			retval = 0; /* following macro beats race condition */
399 			__wait_event_interruptible(sfp->read_wait,
400 				(sdp->detached ||
401 				(srp = sg_get_rq_mark(sfp, req_pack_id))),
402 				retval);
403 			if (sdp->detached) {
404 				retval = -ENODEV;
405 				goto free_old_hdr;
406 			}
407 			if (0 == retval)
408 				break;
409 
410 			/* -ERESTARTSYS as signal hit process */
411 			goto free_old_hdr;
412 		}
413 	}
414 	if (srp->header.interface_id != '\0') {
415 		retval = sg_new_read(sfp, buf, count, srp);
416 		goto free_old_hdr;
417 	}
418 
419 	hp = &srp->header;
420 	if (old_hdr == NULL) {
421 		old_hdr = kmalloc(SZ_SG_HEADER, GFP_KERNEL);
422 		if (! old_hdr) {
423 			retval = -ENOMEM;
424 			goto free_old_hdr;
425 		}
426 	}
427 	memset(old_hdr, 0, SZ_SG_HEADER);
428 	old_hdr->reply_len = (int) hp->timeout;
429 	old_hdr->pack_len = old_hdr->reply_len; /* old, strange behaviour */
430 	old_hdr->pack_id = hp->pack_id;
431 	old_hdr->twelve_byte =
432 	    ((srp->data.cmd_opcode >= 0xc0) && (12 == hp->cmd_len)) ? 1 : 0;
433 	old_hdr->target_status = hp->masked_status;
434 	old_hdr->host_status = hp->host_status;
435 	old_hdr->driver_status = hp->driver_status;
436 	if ((CHECK_CONDITION & hp->masked_status) ||
437 	    (DRIVER_SENSE & hp->driver_status))
438 		memcpy(old_hdr->sense_buffer, srp->sense_b,
439 		       sizeof (old_hdr->sense_buffer));
440 	switch (hp->host_status) {
441 	/* This setup of 'result' is for backward compatibility and is best
442 	   ignored by the user who should use target, host + driver status */
443 	case DID_OK:
444 	case DID_PASSTHROUGH:
445 	case DID_SOFT_ERROR:
446 		old_hdr->result = 0;
447 		break;
448 	case DID_NO_CONNECT:
449 	case DID_BUS_BUSY:
450 	case DID_TIME_OUT:
451 		old_hdr->result = EBUSY;
452 		break;
453 	case DID_BAD_TARGET:
454 	case DID_ABORT:
455 	case DID_PARITY:
456 	case DID_RESET:
457 	case DID_BAD_INTR:
458 		old_hdr->result = EIO;
459 		break;
460 	case DID_ERROR:
461 		old_hdr->result = (srp->sense_b[0] == 0 &&
462 				  hp->masked_status == GOOD) ? 0 : EIO;
463 		break;
464 	default:
465 		old_hdr->result = EIO;
466 		break;
467 	}
468 
469 	/* Now copy the result back to the user buffer.  */
470 	if (count >= SZ_SG_HEADER) {
471 		if (__copy_to_user(buf, old_hdr, SZ_SG_HEADER)) {
472 			retval = -EFAULT;
473 			goto free_old_hdr;
474 		}
475 		buf += SZ_SG_HEADER;
476 		if (count > old_hdr->reply_len)
477 			count = old_hdr->reply_len;
478 		if (count > SZ_SG_HEADER) {
479 			if (sg_read_oxfer(srp, buf, count - SZ_SG_HEADER)) {
480 				retval = -EFAULT;
481 				goto free_old_hdr;
482 			}
483 		}
484 	} else
485 		count = (old_hdr->result == 0) ? 0 : -EIO;
486 	sg_finish_rem_req(srp);
487 	retval = count;
488 free_old_hdr:
489 	kfree(old_hdr);
490 	return retval;
491 }
492 
493 static ssize_t
494 sg_new_read(Sg_fd * sfp, char __user *buf, size_t count, Sg_request * srp)
495 {
496 	sg_io_hdr_t *hp = &srp->header;
497 	int err = 0;
498 	int len;
499 
500 	if (count < SZ_SG_IO_HDR) {
501 		err = -EINVAL;
502 		goto err_out;
503 	}
504 	hp->sb_len_wr = 0;
505 	if ((hp->mx_sb_len > 0) && hp->sbp) {
506 		if ((CHECK_CONDITION & hp->masked_status) ||
507 		    (DRIVER_SENSE & hp->driver_status)) {
508 			int sb_len = SCSI_SENSE_BUFFERSIZE;
509 			sb_len = (hp->mx_sb_len > sb_len) ? sb_len : hp->mx_sb_len;
510 			len = 8 + (int) srp->sense_b[7];	/* Additional sense length field */
511 			len = (len > sb_len) ? sb_len : len;
512 			if (copy_to_user(hp->sbp, srp->sense_b, len)) {
513 				err = -EFAULT;
514 				goto err_out;
515 			}
516 			hp->sb_len_wr = len;
517 		}
518 	}
519 	if (hp->masked_status || hp->host_status || hp->driver_status)
520 		hp->info |= SG_INFO_CHECK;
521 	if (copy_to_user(buf, hp, SZ_SG_IO_HDR)) {
522 		err = -EFAULT;
523 		goto err_out;
524 	}
525 err_out:
526 	sg_finish_rem_req(srp);
527 	return (0 == err) ? count : err;
528 }
529 
530 static ssize_t
531 sg_write(struct file *filp, const char __user *buf, size_t count, loff_t * ppos)
532 {
533 	int mxsize, cmd_size, k;
534 	int input_size, blocking;
535 	unsigned char opcode;
536 	Sg_device *sdp;
537 	Sg_fd *sfp;
538 	Sg_request *srp;
539 	struct sg_header old_hdr;
540 	sg_io_hdr_t *hp;
541 	unsigned char cmnd[MAX_COMMAND_SIZE];
542 
543 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
544 		return -ENXIO;
545 	SCSI_LOG_TIMEOUT(3, printk("sg_write: %s, count=%d\n",
546 				   sdp->disk->disk_name, (int) count));
547 	if (sdp->detached)
548 		return -ENODEV;
549 	if (!((filp->f_flags & O_NONBLOCK) ||
550 	      scsi_block_when_processing_errors(sdp->device)))
551 		return -ENXIO;
552 
553 	if (!access_ok(VERIFY_READ, buf, count))
554 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
555 	if (count < SZ_SG_HEADER)
556 		return -EIO;
557 	if (__copy_from_user(&old_hdr, buf, SZ_SG_HEADER))
558 		return -EFAULT;
559 	blocking = !(filp->f_flags & O_NONBLOCK);
560 	if (old_hdr.reply_len < 0)
561 		return sg_new_write(sfp, filp, buf, count, blocking, 0, NULL);
562 	if (count < (SZ_SG_HEADER + 6))
563 		return -EIO;	/* The minimum scsi command length is 6 bytes. */
564 
565 	if (!(srp = sg_add_request(sfp))) {
566 		SCSI_LOG_TIMEOUT(1, printk("sg_write: queue full\n"));
567 		return -EDOM;
568 	}
569 	buf += SZ_SG_HEADER;
570 	__get_user(opcode, buf);
571 	if (sfp->next_cmd_len > 0) {
572 		if (sfp->next_cmd_len > MAX_COMMAND_SIZE) {
573 			SCSI_LOG_TIMEOUT(1, printk("sg_write: command length too long\n"));
574 			sfp->next_cmd_len = 0;
575 			sg_remove_request(sfp, srp);
576 			return -EIO;
577 		}
578 		cmd_size = sfp->next_cmd_len;
579 		sfp->next_cmd_len = 0;	/* reset so only this write() effected */
580 	} else {
581 		cmd_size = COMMAND_SIZE(opcode);	/* based on SCSI command group */
582 		if ((opcode >= 0xc0) && old_hdr.twelve_byte)
583 			cmd_size = 12;
584 	}
585 	SCSI_LOG_TIMEOUT(4, printk(
586 		"sg_write:   scsi opcode=0x%02x, cmd_size=%d\n", (int) opcode, cmd_size));
587 /* Determine buffer size.  */
588 	input_size = count - cmd_size;
589 	mxsize = (input_size > old_hdr.reply_len) ? input_size : old_hdr.reply_len;
590 	mxsize -= SZ_SG_HEADER;
591 	input_size -= SZ_SG_HEADER;
592 	if (input_size < 0) {
593 		sg_remove_request(sfp, srp);
594 		return -EIO;	/* User did not pass enough bytes for this command. */
595 	}
596 	hp = &srp->header;
597 	hp->interface_id = '\0';	/* indicator of old interface tunnelled */
598 	hp->cmd_len = (unsigned char) cmd_size;
599 	hp->iovec_count = 0;
600 	hp->mx_sb_len = 0;
601 	if (input_size > 0)
602 		hp->dxfer_direction = (old_hdr.reply_len > SZ_SG_HEADER) ?
603 		    SG_DXFER_TO_FROM_DEV : SG_DXFER_TO_DEV;
604 	else
605 		hp->dxfer_direction = (mxsize > 0) ? SG_DXFER_FROM_DEV : SG_DXFER_NONE;
606 	hp->dxfer_len = mxsize;
607 	if (hp->dxfer_direction == SG_DXFER_TO_DEV)
608 		hp->dxferp = (char __user *)buf + cmd_size;
609 	else
610 		hp->dxferp = NULL;
611 	hp->sbp = NULL;
612 	hp->timeout = old_hdr.reply_len;	/* structure abuse ... */
613 	hp->flags = input_size;	/* structure abuse ... */
614 	hp->pack_id = old_hdr.pack_id;
615 	hp->usr_ptr = NULL;
616 	if (__copy_from_user(cmnd, buf, cmd_size))
617 		return -EFAULT;
618 	/*
619 	 * SG_DXFER_TO_FROM_DEV is functionally equivalent to SG_DXFER_FROM_DEV,
620 	 * but is is possible that the app intended SG_DXFER_TO_DEV, because there
621 	 * is a non-zero input_size, so emit a warning.
622 	 */
623 	if (hp->dxfer_direction == SG_DXFER_TO_FROM_DEV) {
624 		static char cmd[TASK_COMM_LEN];
625 		if (strcmp(current->comm, cmd) && printk_ratelimit()) {
626 			printk(KERN_WARNING
627 			       "sg_write: data in/out %d/%d bytes for SCSI command 0x%x--"
628 			       "guessing data in;\n" KERN_WARNING "   "
629 			       "program %s not setting count and/or reply_len properly\n",
630 			       old_hdr.reply_len - (int)SZ_SG_HEADER,
631 			       input_size, (unsigned int) cmnd[0],
632 			       current->comm);
633 			strcpy(cmd, current->comm);
634 		}
635 	}
636 	k = sg_common_write(sfp, srp, cmnd, sfp->timeout, blocking);
637 	return (k < 0) ? k : count;
638 }
639 
640 static ssize_t
641 sg_new_write(Sg_fd *sfp, struct file *file, const char __user *buf,
642 		 size_t count, int blocking, int read_only,
643 		 Sg_request **o_srp)
644 {
645 	int k;
646 	Sg_request *srp;
647 	sg_io_hdr_t *hp;
648 	unsigned char cmnd[MAX_COMMAND_SIZE];
649 	int timeout;
650 	unsigned long ul_timeout;
651 
652 	if (count < SZ_SG_IO_HDR)
653 		return -EINVAL;
654 	if (!access_ok(VERIFY_READ, buf, count))
655 		return -EFAULT; /* protects following copy_from_user()s + get_user()s */
656 
657 	sfp->cmd_q = 1;	/* when sg_io_hdr seen, set command queuing on */
658 	if (!(srp = sg_add_request(sfp))) {
659 		SCSI_LOG_TIMEOUT(1, printk("sg_new_write: queue full\n"));
660 		return -EDOM;
661 	}
662 	hp = &srp->header;
663 	if (__copy_from_user(hp, buf, SZ_SG_IO_HDR)) {
664 		sg_remove_request(sfp, srp);
665 		return -EFAULT;
666 	}
667 	if (hp->interface_id != 'S') {
668 		sg_remove_request(sfp, srp);
669 		return -ENOSYS;
670 	}
671 	if (hp->flags & SG_FLAG_MMAP_IO) {
672 		if (hp->dxfer_len > sfp->reserve.bufflen) {
673 			sg_remove_request(sfp, srp);
674 			return -ENOMEM;	/* MMAP_IO size must fit in reserve buffer */
675 		}
676 		if (hp->flags & SG_FLAG_DIRECT_IO) {
677 			sg_remove_request(sfp, srp);
678 			return -EINVAL;	/* either MMAP_IO or DIRECT_IO (not both) */
679 		}
680 		if (sg_res_in_use(sfp)) {
681 			sg_remove_request(sfp, srp);
682 			return -EBUSY;	/* reserve buffer already being used */
683 		}
684 	}
685 	ul_timeout = msecs_to_jiffies(srp->header.timeout);
686 	timeout = (ul_timeout < INT_MAX) ? ul_timeout : INT_MAX;
687 	if ((!hp->cmdp) || (hp->cmd_len < 6) || (hp->cmd_len > sizeof (cmnd))) {
688 		sg_remove_request(sfp, srp);
689 		return -EMSGSIZE;
690 	}
691 	if (!access_ok(VERIFY_READ, hp->cmdp, hp->cmd_len)) {
692 		sg_remove_request(sfp, srp);
693 		return -EFAULT;	/* protects following copy_from_user()s + get_user()s */
694 	}
695 	if (__copy_from_user(cmnd, hp->cmdp, hp->cmd_len)) {
696 		sg_remove_request(sfp, srp);
697 		return -EFAULT;
698 	}
699 	if (read_only && sg_allow_access(file, cmnd)) {
700 		sg_remove_request(sfp, srp);
701 		return -EPERM;
702 	}
703 	k = sg_common_write(sfp, srp, cmnd, timeout, blocking);
704 	if (k < 0)
705 		return k;
706 	if (o_srp)
707 		*o_srp = srp;
708 	return count;
709 }
710 
711 static int
712 sg_common_write(Sg_fd * sfp, Sg_request * srp,
713 		unsigned char *cmnd, int timeout, int blocking)
714 {
715 	int k, data_dir;
716 	Sg_device *sdp = sfp->parentdp;
717 	sg_io_hdr_t *hp = &srp->header;
718 
719 	srp->data.cmd_opcode = cmnd[0];	/* hold opcode of command */
720 	hp->status = 0;
721 	hp->masked_status = 0;
722 	hp->msg_status = 0;
723 	hp->info = 0;
724 	hp->host_status = 0;
725 	hp->driver_status = 0;
726 	hp->resid = 0;
727 	SCSI_LOG_TIMEOUT(4, printk("sg_common_write:  scsi opcode=0x%02x, cmd_size=%d\n",
728 			  (int) cmnd[0], (int) hp->cmd_len));
729 
730 	k = sg_start_req(srp, cmnd);
731 	if (k) {
732 		SCSI_LOG_TIMEOUT(1, printk("sg_common_write: start_req err=%d\n", k));
733 		sg_finish_rem_req(srp);
734 		return k;	/* probably out of space --> ENOMEM */
735 	}
736 	if (sdp->detached) {
737 		sg_finish_rem_req(srp);
738 		return -ENODEV;
739 	}
740 
741 	switch (hp->dxfer_direction) {
742 	case SG_DXFER_TO_FROM_DEV:
743 	case SG_DXFER_FROM_DEV:
744 		data_dir = DMA_FROM_DEVICE;
745 		break;
746 	case SG_DXFER_TO_DEV:
747 		data_dir = DMA_TO_DEVICE;
748 		break;
749 	case SG_DXFER_UNKNOWN:
750 		data_dir = DMA_BIDIRECTIONAL;
751 		break;
752 	default:
753 		data_dir = DMA_NONE;
754 		break;
755 	}
756 	hp->duration = jiffies_to_msecs(jiffies);
757 
758 	srp->rq->timeout = timeout;
759 	blk_execute_rq_nowait(sdp->device->request_queue, sdp->disk,
760 			      srp->rq, 1, sg_rq_end_io);
761 	return 0;
762 }
763 
764 static int
765 sg_srp_done(Sg_request *srp, Sg_fd *sfp)
766 {
767 	unsigned long iflags;
768 	int done;
769 
770 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
771 	done = srp->done;
772 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
773 	return done;
774 }
775 
776 static int
777 sg_ioctl(struct inode *inode, struct file *filp,
778 	 unsigned int cmd_in, unsigned long arg)
779 {
780 	void __user *p = (void __user *)arg;
781 	int __user *ip = p;
782 	int result, val, read_only;
783 	Sg_device *sdp;
784 	Sg_fd *sfp;
785 	Sg_request *srp;
786 	unsigned long iflags;
787 
788 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
789 		return -ENXIO;
790 
791 	SCSI_LOG_TIMEOUT(3, printk("sg_ioctl: %s, cmd=0x%x\n",
792 				   sdp->disk->disk_name, (int) cmd_in));
793 	read_only = (O_RDWR != (filp->f_flags & O_ACCMODE));
794 
795 	switch (cmd_in) {
796 	case SG_IO:
797 		{
798 			int blocking = 1;	/* ignore O_NONBLOCK flag */
799 
800 			if (sdp->detached)
801 				return -ENODEV;
802 			if (!scsi_block_when_processing_errors(sdp->device))
803 				return -ENXIO;
804 			if (!access_ok(VERIFY_WRITE, p, SZ_SG_IO_HDR))
805 				return -EFAULT;
806 			result =
807 			    sg_new_write(sfp, filp, p, SZ_SG_IO_HDR,
808 					 blocking, read_only, &srp);
809 			if (result < 0)
810 				return result;
811 			srp->sg_io_owned = 1;
812 			while (1) {
813 				result = 0;	/* following macro to beat race condition */
814 				__wait_event_interruptible(sfp->read_wait,
815 					(sdp->detached || sfp->closed || sg_srp_done(srp, sfp)),
816 							   result);
817 				if (sdp->detached)
818 					return -ENODEV;
819 				if (sfp->closed)
820 					return 0;	/* request packet dropped already */
821 				if (0 == result)
822 					break;
823 				srp->orphan = 1;
824 				return result;	/* -ERESTARTSYS because signal hit process */
825 			}
826 			write_lock_irqsave(&sfp->rq_list_lock, iflags);
827 			srp->done = 2;
828 			write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
829 			result = sg_new_read(sfp, p, SZ_SG_IO_HDR, srp);
830 			return (result < 0) ? result : 0;
831 		}
832 	case SG_SET_TIMEOUT:
833 		result = get_user(val, ip);
834 		if (result)
835 			return result;
836 		if (val < 0)
837 			return -EIO;
838 		if (val >= MULDIV (INT_MAX, USER_HZ, HZ))
839 		    val = MULDIV (INT_MAX, USER_HZ, HZ);
840 		sfp->timeout_user = val;
841 		sfp->timeout = MULDIV (val, HZ, USER_HZ);
842 
843 		return 0;
844 	case SG_GET_TIMEOUT:	/* N.B. User receives timeout as return value */
845 				/* strange ..., for backward compatibility */
846 		return sfp->timeout_user;
847 	case SG_SET_FORCE_LOW_DMA:
848 		result = get_user(val, ip);
849 		if (result)
850 			return result;
851 		if (val) {
852 			sfp->low_dma = 1;
853 			if ((0 == sfp->low_dma) && (0 == sg_res_in_use(sfp))) {
854 				val = (int) sfp->reserve.bufflen;
855 				sg_remove_scat(&sfp->reserve);
856 				sg_build_reserve(sfp, val);
857 			}
858 		} else {
859 			if (sdp->detached)
860 				return -ENODEV;
861 			sfp->low_dma = sdp->device->host->unchecked_isa_dma;
862 		}
863 		return 0;
864 	case SG_GET_LOW_DMA:
865 		return put_user((int) sfp->low_dma, ip);
866 	case SG_GET_SCSI_ID:
867 		if (!access_ok(VERIFY_WRITE, p, sizeof (sg_scsi_id_t)))
868 			return -EFAULT;
869 		else {
870 			sg_scsi_id_t __user *sg_idp = p;
871 
872 			if (sdp->detached)
873 				return -ENODEV;
874 			__put_user((int) sdp->device->host->host_no,
875 				   &sg_idp->host_no);
876 			__put_user((int) sdp->device->channel,
877 				   &sg_idp->channel);
878 			__put_user((int) sdp->device->id, &sg_idp->scsi_id);
879 			__put_user((int) sdp->device->lun, &sg_idp->lun);
880 			__put_user((int) sdp->device->type, &sg_idp->scsi_type);
881 			__put_user((short) sdp->device->host->cmd_per_lun,
882 				   &sg_idp->h_cmd_per_lun);
883 			__put_user((short) sdp->device->queue_depth,
884 				   &sg_idp->d_queue_depth);
885 			__put_user(0, &sg_idp->unused[0]);
886 			__put_user(0, &sg_idp->unused[1]);
887 			return 0;
888 		}
889 	case SG_SET_FORCE_PACK_ID:
890 		result = get_user(val, ip);
891 		if (result)
892 			return result;
893 		sfp->force_packid = val ? 1 : 0;
894 		return 0;
895 	case SG_GET_PACK_ID:
896 		if (!access_ok(VERIFY_WRITE, ip, sizeof (int)))
897 			return -EFAULT;
898 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
899 		for (srp = sfp->headrp; srp; srp = srp->nextrp) {
900 			if ((1 == srp->done) && (!srp->sg_io_owned)) {
901 				read_unlock_irqrestore(&sfp->rq_list_lock,
902 						       iflags);
903 				__put_user(srp->header.pack_id, ip);
904 				return 0;
905 			}
906 		}
907 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
908 		__put_user(-1, ip);
909 		return 0;
910 	case SG_GET_NUM_WAITING:
911 		read_lock_irqsave(&sfp->rq_list_lock, iflags);
912 		for (val = 0, srp = sfp->headrp; srp; srp = srp->nextrp) {
913 			if ((1 == srp->done) && (!srp->sg_io_owned))
914 				++val;
915 		}
916 		read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
917 		return put_user(val, ip);
918 	case SG_GET_SG_TABLESIZE:
919 		return put_user(sdp->sg_tablesize, ip);
920 	case SG_SET_RESERVED_SIZE:
921 		result = get_user(val, ip);
922 		if (result)
923 			return result;
924                 if (val < 0)
925                         return -EINVAL;
926 		val = min_t(int, val,
927 				sdp->device->request_queue->max_sectors * 512);
928 		if (val != sfp->reserve.bufflen) {
929 			if (sg_res_in_use(sfp) || sfp->mmap_called)
930 				return -EBUSY;
931 			sg_remove_scat(&sfp->reserve);
932 			sg_build_reserve(sfp, val);
933 		}
934 		return 0;
935 	case SG_GET_RESERVED_SIZE:
936 		val = min_t(int, sfp->reserve.bufflen,
937 				sdp->device->request_queue->max_sectors * 512);
938 		return put_user(val, ip);
939 	case SG_SET_COMMAND_Q:
940 		result = get_user(val, ip);
941 		if (result)
942 			return result;
943 		sfp->cmd_q = val ? 1 : 0;
944 		return 0;
945 	case SG_GET_COMMAND_Q:
946 		return put_user((int) sfp->cmd_q, ip);
947 	case SG_SET_KEEP_ORPHAN:
948 		result = get_user(val, ip);
949 		if (result)
950 			return result;
951 		sfp->keep_orphan = val;
952 		return 0;
953 	case SG_GET_KEEP_ORPHAN:
954 		return put_user((int) sfp->keep_orphan, ip);
955 	case SG_NEXT_CMD_LEN:
956 		result = get_user(val, ip);
957 		if (result)
958 			return result;
959 		sfp->next_cmd_len = (val > 0) ? val : 0;
960 		return 0;
961 	case SG_GET_VERSION_NUM:
962 		return put_user(sg_version_num, ip);
963 	case SG_GET_ACCESS_COUNT:
964 		/* faked - we don't have a real access count anymore */
965 		val = (sdp->device ? 1 : 0);
966 		return put_user(val, ip);
967 	case SG_GET_REQUEST_TABLE:
968 		if (!access_ok(VERIFY_WRITE, p, SZ_SG_REQ_INFO * SG_MAX_QUEUE))
969 			return -EFAULT;
970 		else {
971 			sg_req_info_t *rinfo;
972 			unsigned int ms;
973 
974 			rinfo = kmalloc(SZ_SG_REQ_INFO * SG_MAX_QUEUE,
975 								GFP_KERNEL);
976 			if (!rinfo)
977 				return -ENOMEM;
978 			read_lock_irqsave(&sfp->rq_list_lock, iflags);
979 			for (srp = sfp->headrp, val = 0; val < SG_MAX_QUEUE;
980 			     ++val, srp = srp ? srp->nextrp : srp) {
981 				memset(&rinfo[val], 0, SZ_SG_REQ_INFO);
982 				if (srp) {
983 					rinfo[val].req_state = srp->done + 1;
984 					rinfo[val].problem =
985 					    srp->header.masked_status &
986 					    srp->header.host_status &
987 					    srp->header.driver_status;
988 					if (srp->done)
989 						rinfo[val].duration =
990 							srp->header.duration;
991 					else {
992 						ms = jiffies_to_msecs(jiffies);
993 						rinfo[val].duration =
994 						    (ms > srp->header.duration) ?
995 						    (ms - srp->header.duration) : 0;
996 					}
997 					rinfo[val].orphan = srp->orphan;
998 					rinfo[val].sg_io_owned =
999 							srp->sg_io_owned;
1000 					rinfo[val].pack_id =
1001 							srp->header.pack_id;
1002 					rinfo[val].usr_ptr =
1003 							srp->header.usr_ptr;
1004 				}
1005 			}
1006 			read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1007 			result = __copy_to_user(p, rinfo,
1008 						SZ_SG_REQ_INFO * SG_MAX_QUEUE);
1009 			result = result ? -EFAULT : 0;
1010 			kfree(rinfo);
1011 			return result;
1012 		}
1013 	case SG_EMULATED_HOST:
1014 		if (sdp->detached)
1015 			return -ENODEV;
1016 		return put_user(sdp->device->host->hostt->emulated, ip);
1017 	case SG_SCSI_RESET:
1018 		if (sdp->detached)
1019 			return -ENODEV;
1020 		if (filp->f_flags & O_NONBLOCK) {
1021 			if (scsi_host_in_recovery(sdp->device->host))
1022 				return -EBUSY;
1023 		} else if (!scsi_block_when_processing_errors(sdp->device))
1024 			return -EBUSY;
1025 		result = get_user(val, ip);
1026 		if (result)
1027 			return result;
1028 		if (SG_SCSI_RESET_NOTHING == val)
1029 			return 0;
1030 		switch (val) {
1031 		case SG_SCSI_RESET_DEVICE:
1032 			val = SCSI_TRY_RESET_DEVICE;
1033 			break;
1034 		case SG_SCSI_RESET_TARGET:
1035 			val = SCSI_TRY_RESET_TARGET;
1036 			break;
1037 		case SG_SCSI_RESET_BUS:
1038 			val = SCSI_TRY_RESET_BUS;
1039 			break;
1040 		case SG_SCSI_RESET_HOST:
1041 			val = SCSI_TRY_RESET_HOST;
1042 			break;
1043 		default:
1044 			return -EINVAL;
1045 		}
1046 		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1047 			return -EACCES;
1048 		return (scsi_reset_provider(sdp->device, val) ==
1049 			SUCCESS) ? 0 : -EIO;
1050 	case SCSI_IOCTL_SEND_COMMAND:
1051 		if (sdp->detached)
1052 			return -ENODEV;
1053 		if (read_only) {
1054 			unsigned char opcode = WRITE_6;
1055 			Scsi_Ioctl_Command __user *siocp = p;
1056 
1057 			if (copy_from_user(&opcode, siocp->data, 1))
1058 				return -EFAULT;
1059 			if (sg_allow_access(filp, &opcode))
1060 				return -EPERM;
1061 		}
1062 		return sg_scsi_ioctl(filp, sdp->device->request_queue, NULL, p);
1063 	case SG_SET_DEBUG:
1064 		result = get_user(val, ip);
1065 		if (result)
1066 			return result;
1067 		sdp->sgdebug = (char) val;
1068 		return 0;
1069 	case SCSI_IOCTL_GET_IDLUN:
1070 	case SCSI_IOCTL_GET_BUS_NUMBER:
1071 	case SCSI_IOCTL_PROBE_HOST:
1072 	case SG_GET_TRANSFORM:
1073 		if (sdp->detached)
1074 			return -ENODEV;
1075 		return scsi_ioctl(sdp->device, cmd_in, p);
1076 	case BLKSECTGET:
1077 		return put_user(sdp->device->request_queue->max_sectors * 512,
1078 				ip);
1079 	case BLKTRACESETUP:
1080 		return blk_trace_setup(sdp->device->request_queue,
1081 				       sdp->disk->disk_name,
1082 				       sdp->device->sdev_gendev.devt,
1083 				       (char *)arg);
1084 	case BLKTRACESTART:
1085 		return blk_trace_startstop(sdp->device->request_queue, 1);
1086 	case BLKTRACESTOP:
1087 		return blk_trace_startstop(sdp->device->request_queue, 0);
1088 	case BLKTRACETEARDOWN:
1089 		return blk_trace_remove(sdp->device->request_queue);
1090 	default:
1091 		if (read_only)
1092 			return -EPERM;	/* don't know so take safe approach */
1093 		return scsi_ioctl(sdp->device, cmd_in, p);
1094 	}
1095 }
1096 
1097 #ifdef CONFIG_COMPAT
1098 static long sg_compat_ioctl(struct file *filp, unsigned int cmd_in, unsigned long arg)
1099 {
1100 	Sg_device *sdp;
1101 	Sg_fd *sfp;
1102 	struct scsi_device *sdev;
1103 
1104 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1105 		return -ENXIO;
1106 
1107 	sdev = sdp->device;
1108 	if (sdev->host->hostt->compat_ioctl) {
1109 		int ret;
1110 
1111 		ret = sdev->host->hostt->compat_ioctl(sdev, cmd_in, (void __user *)arg);
1112 
1113 		return ret;
1114 	}
1115 
1116 	return -ENOIOCTLCMD;
1117 }
1118 #endif
1119 
1120 static unsigned int
1121 sg_poll(struct file *filp, poll_table * wait)
1122 {
1123 	unsigned int res = 0;
1124 	Sg_device *sdp;
1125 	Sg_fd *sfp;
1126 	Sg_request *srp;
1127 	int count = 0;
1128 	unsigned long iflags;
1129 
1130 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp))
1131 	    || sfp->closed)
1132 		return POLLERR;
1133 	poll_wait(filp, &sfp->read_wait, wait);
1134 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1135 	for (srp = sfp->headrp; srp; srp = srp->nextrp) {
1136 		/* if any read waiting, flag it */
1137 		if ((0 == res) && (1 == srp->done) && (!srp->sg_io_owned))
1138 			res = POLLIN | POLLRDNORM;
1139 		++count;
1140 	}
1141 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1142 
1143 	if (sdp->detached)
1144 		res |= POLLHUP;
1145 	else if (!sfp->cmd_q) {
1146 		if (0 == count)
1147 			res |= POLLOUT | POLLWRNORM;
1148 	} else if (count < SG_MAX_QUEUE)
1149 		res |= POLLOUT | POLLWRNORM;
1150 	SCSI_LOG_TIMEOUT(3, printk("sg_poll: %s, res=0x%x\n",
1151 				   sdp->disk->disk_name, (int) res));
1152 	return res;
1153 }
1154 
1155 static int
1156 sg_fasync(int fd, struct file *filp, int mode)
1157 {
1158 	int retval;
1159 	Sg_device *sdp;
1160 	Sg_fd *sfp;
1161 
1162 	if ((!(sfp = (Sg_fd *) filp->private_data)) || (!(sdp = sfp->parentdp)))
1163 		return -ENXIO;
1164 	SCSI_LOG_TIMEOUT(3, printk("sg_fasync: %s, mode=%d\n",
1165 				   sdp->disk->disk_name, mode));
1166 
1167 	retval = fasync_helper(fd, filp, mode, &sfp->async_qp);
1168 	return (retval < 0) ? retval : 0;
1169 }
1170 
1171 static int
1172 sg_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1173 {
1174 	Sg_fd *sfp;
1175 	unsigned long offset, len, sa;
1176 	Sg_scatter_hold *rsv_schp;
1177 	int k, length;
1178 
1179 	if ((NULL == vma) || (!(sfp = (Sg_fd *) vma->vm_private_data)))
1180 		return VM_FAULT_SIGBUS;
1181 	rsv_schp = &sfp->reserve;
1182 	offset = vmf->pgoff << PAGE_SHIFT;
1183 	if (offset >= rsv_schp->bufflen)
1184 		return VM_FAULT_SIGBUS;
1185 	SCSI_LOG_TIMEOUT(3, printk("sg_vma_fault: offset=%lu, scatg=%d\n",
1186 				   offset, rsv_schp->k_use_sg));
1187 	sa = vma->vm_start;
1188 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1189 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1190 		len = vma->vm_end - sa;
1191 		len = (len < length) ? len : length;
1192 		if (offset < len) {
1193 			struct page *page = nth_page(rsv_schp->pages[k],
1194 						     offset >> PAGE_SHIFT);
1195 			get_page(page);	/* increment page count */
1196 			vmf->page = page;
1197 			return 0; /* success */
1198 		}
1199 		sa += len;
1200 		offset -= len;
1201 	}
1202 
1203 	return VM_FAULT_SIGBUS;
1204 }
1205 
1206 static struct vm_operations_struct sg_mmap_vm_ops = {
1207 	.fault = sg_vma_fault,
1208 };
1209 
1210 static int
1211 sg_mmap(struct file *filp, struct vm_area_struct *vma)
1212 {
1213 	Sg_fd *sfp;
1214 	unsigned long req_sz, len, sa;
1215 	Sg_scatter_hold *rsv_schp;
1216 	int k, length;
1217 
1218 	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
1219 		return -ENXIO;
1220 	req_sz = vma->vm_end - vma->vm_start;
1221 	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",
1222 				   (void *) vma->vm_start, (int) req_sz));
1223 	if (vma->vm_pgoff)
1224 		return -EINVAL;	/* want no offset */
1225 	rsv_schp = &sfp->reserve;
1226 	if (req_sz > rsv_schp->bufflen)
1227 		return -ENOMEM;	/* cannot map more than reserved buffer */
1228 
1229 	sa = vma->vm_start;
1230 	length = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1231 	for (k = 0; k < rsv_schp->k_use_sg && sa < vma->vm_end; k++) {
1232 		len = vma->vm_end - sa;
1233 		len = (len < length) ? len : length;
1234 		sa += len;
1235 	}
1236 
1237 	sfp->mmap_called = 1;
1238 	vma->vm_flags |= VM_RESERVED;
1239 	vma->vm_private_data = sfp;
1240 	vma->vm_ops = &sg_mmap_vm_ops;
1241 	return 0;
1242 }
1243 
1244 /*
1245  * This function is a "bottom half" handler that is called by the mid
1246  * level when a command is completed (or has failed).
1247  */
1248 static void sg_rq_end_io(struct request *rq, int uptodate)
1249 {
1250 	struct sg_request *srp = rq->end_io_data;
1251 	Sg_device *sdp = NULL;
1252 	Sg_fd *sfp;
1253 	unsigned long iflags;
1254 	unsigned int ms;
1255 	char *sense;
1256 	int result, resid;
1257 
1258 	if (NULL == srp) {
1259 		printk(KERN_ERR "sg_cmd_done: NULL request\n");
1260 		return;
1261 	}
1262 	sfp = srp->parentfp;
1263 	if (sfp)
1264 		sdp = sfp->parentdp;
1265 	if ((NULL == sdp) || sdp->detached) {
1266 		printk(KERN_INFO "sg_cmd_done: device detached\n");
1267 		return;
1268 	}
1269 
1270 	sense = rq->sense;
1271 	result = rq->errors;
1272 	resid = rq->data_len;
1273 
1274 	SCSI_LOG_TIMEOUT(4, printk("sg_cmd_done: %s, pack_id=%d, res=0x%x\n",
1275 		sdp->disk->disk_name, srp->header.pack_id, result));
1276 	srp->header.resid = resid;
1277 	ms = jiffies_to_msecs(jiffies);
1278 	srp->header.duration = (ms > srp->header.duration) ?
1279 				(ms - srp->header.duration) : 0;
1280 	if (0 != result) {
1281 		struct scsi_sense_hdr sshdr;
1282 
1283 		srp->header.status = 0xff & result;
1284 		srp->header.masked_status = status_byte(result);
1285 		srp->header.msg_status = msg_byte(result);
1286 		srp->header.host_status = host_byte(result);
1287 		srp->header.driver_status = driver_byte(result);
1288 		if ((sdp->sgdebug > 0) &&
1289 		    ((CHECK_CONDITION == srp->header.masked_status) ||
1290 		     (COMMAND_TERMINATED == srp->header.masked_status)))
1291 			__scsi_print_sense("sg_cmd_done", sense,
1292 					   SCSI_SENSE_BUFFERSIZE);
1293 
1294 		/* Following if statement is a patch supplied by Eric Youngdale */
1295 		if (driver_byte(result) != 0
1296 		    && scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)
1297 		    && !scsi_sense_is_deferred(&sshdr)
1298 		    && sshdr.sense_key == UNIT_ATTENTION
1299 		    && sdp->device->removable) {
1300 			/* Detected possible disc change. Set the bit - this */
1301 			/* may be used if there are filesystems using this device */
1302 			sdp->device->changed = 1;
1303 		}
1304 	}
1305 	/* Rely on write phase to clean out srp status values, so no "else" */
1306 
1307 	if (sfp->closed) {	/* whoops this fd already released, cleanup */
1308 		SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, freeing ...\n"));
1309 		sg_finish_rem_req(srp);
1310 		srp = NULL;
1311 		if (NULL == sfp->headrp) {
1312 			SCSI_LOG_TIMEOUT(1, printk("sg_cmd_done: already closed, final cleanup\n"));
1313 			if (0 == sg_remove_sfp(sdp, sfp)) {	/* device still present */
1314 				scsi_device_put(sdp->device);
1315 			}
1316 			sfp = NULL;
1317 		}
1318 	} else if (srp && srp->orphan) {
1319 		if (sfp->keep_orphan)
1320 			srp->sg_io_owned = 0;
1321 		else {
1322 			sg_finish_rem_req(srp);
1323 			srp = NULL;
1324 		}
1325 	}
1326 	if (sfp && srp) {
1327 		/* Now wake up any sg_read() that is waiting for this packet. */
1328 		kill_fasync(&sfp->async_qp, SIGPOLL, POLL_IN);
1329 		write_lock_irqsave(&sfp->rq_list_lock, iflags);
1330 		srp->done = 1;
1331 		wake_up_interruptible(&sfp->read_wait);
1332 		write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1333 	}
1334 }
1335 
1336 static struct file_operations sg_fops = {
1337 	.owner = THIS_MODULE,
1338 	.read = sg_read,
1339 	.write = sg_write,
1340 	.poll = sg_poll,
1341 	.ioctl = sg_ioctl,
1342 #ifdef CONFIG_COMPAT
1343 	.compat_ioctl = sg_compat_ioctl,
1344 #endif
1345 	.open = sg_open,
1346 	.mmap = sg_mmap,
1347 	.release = sg_release,
1348 	.fasync = sg_fasync,
1349 };
1350 
1351 static struct class *sg_sysfs_class;
1352 
1353 static int sg_sysfs_valid = 0;
1354 
1355 static Sg_device *sg_alloc(struct gendisk *disk, struct scsi_device *scsidp)
1356 {
1357 	struct request_queue *q = scsidp->request_queue;
1358 	Sg_device *sdp;
1359 	unsigned long iflags;
1360 	int error;
1361 	u32 k;
1362 
1363 	sdp = kzalloc(sizeof(Sg_device), GFP_KERNEL);
1364 	if (!sdp) {
1365 		printk(KERN_WARNING "kmalloc Sg_device failure\n");
1366 		return ERR_PTR(-ENOMEM);
1367 	}
1368 	error = -ENOMEM;
1369 	if (!idr_pre_get(&sg_index_idr, GFP_KERNEL)) {
1370 		printk(KERN_WARNING "idr expansion Sg_device failure\n");
1371 		goto out;
1372 	}
1373 
1374 	write_lock_irqsave(&sg_index_lock, iflags);
1375 	error = idr_get_new(&sg_index_idr, sdp, &k);
1376 	write_unlock_irqrestore(&sg_index_lock, iflags);
1377 
1378 	if (error) {
1379 		printk(KERN_WARNING "idr allocation Sg_device failure: %d\n",
1380 		       error);
1381 		goto out;
1382 	}
1383 
1384 	if (unlikely(k >= SG_MAX_DEVS))
1385 		goto overflow;
1386 
1387 	SCSI_LOG_TIMEOUT(3, printk("sg_alloc: dev=%d \n", k));
1388 	sprintf(disk->disk_name, "sg%d", k);
1389 	disk->first_minor = k;
1390 	sdp->disk = disk;
1391 	sdp->device = scsidp;
1392 	init_waitqueue_head(&sdp->o_excl_wait);
1393 	sdp->sg_tablesize = min(q->max_hw_segments, q->max_phys_segments);
1394 	sdp->index = k;
1395 
1396 	error = 0;
1397  out:
1398 	if (error) {
1399 		kfree(sdp);
1400 		return ERR_PTR(error);
1401 	}
1402 	return sdp;
1403 
1404  overflow:
1405 	sdev_printk(KERN_WARNING, scsidp,
1406 		    "Unable to attach sg device type=%d, minor "
1407 		    "number exceeds %d\n", scsidp->type, SG_MAX_DEVS - 1);
1408 	error = -ENODEV;
1409 	goto out;
1410 }
1411 
1412 static int
1413 sg_add(struct device *cl_dev, struct class_interface *cl_intf)
1414 {
1415 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1416 	struct gendisk *disk;
1417 	Sg_device *sdp = NULL;
1418 	struct cdev * cdev = NULL;
1419 	int error;
1420 	unsigned long iflags;
1421 
1422 	disk = alloc_disk(1);
1423 	if (!disk) {
1424 		printk(KERN_WARNING "alloc_disk failed\n");
1425 		return -ENOMEM;
1426 	}
1427 	disk->major = SCSI_GENERIC_MAJOR;
1428 
1429 	error = -ENOMEM;
1430 	cdev = cdev_alloc();
1431 	if (!cdev) {
1432 		printk(KERN_WARNING "cdev_alloc failed\n");
1433 		goto out;
1434 	}
1435 	cdev->owner = THIS_MODULE;
1436 	cdev->ops = &sg_fops;
1437 
1438 	sdp = sg_alloc(disk, scsidp);
1439 	if (IS_ERR(sdp)) {
1440 		printk(KERN_WARNING "sg_alloc failed\n");
1441 		error = PTR_ERR(sdp);
1442 		goto out;
1443 	}
1444 
1445 	error = cdev_add(cdev, MKDEV(SCSI_GENERIC_MAJOR, sdp->index), 1);
1446 	if (error)
1447 		goto cdev_add_err;
1448 
1449 	sdp->cdev = cdev;
1450 	if (sg_sysfs_valid) {
1451 		struct device *sg_class_member;
1452 
1453 		sg_class_member = device_create_drvdata(sg_sysfs_class,
1454 							cl_dev->parent,
1455 							MKDEV(SCSI_GENERIC_MAJOR,
1456 							      sdp->index),
1457 							sdp,
1458 							"%s", disk->disk_name);
1459 		if (IS_ERR(sg_class_member)) {
1460 			printk(KERN_ERR "sg_add: "
1461 			       "device_create failed\n");
1462 			error = PTR_ERR(sg_class_member);
1463 			goto cdev_add_err;
1464 		}
1465 		error = sysfs_create_link(&scsidp->sdev_gendev.kobj,
1466 					  &sg_class_member->kobj, "generic");
1467 		if (error)
1468 			printk(KERN_ERR "sg_add: unable to make symlink "
1469 					"'generic' back to sg%d\n", sdp->index);
1470 	} else
1471 		printk(KERN_WARNING "sg_add: sg_sys Invalid\n");
1472 
1473 	sdev_printk(KERN_NOTICE, scsidp,
1474 		    "Attached scsi generic sg%d type %d\n", sdp->index,
1475 		    scsidp->type);
1476 
1477 	dev_set_drvdata(cl_dev, sdp);
1478 
1479 	return 0;
1480 
1481 cdev_add_err:
1482 	write_lock_irqsave(&sg_index_lock, iflags);
1483 	idr_remove(&sg_index_idr, sdp->index);
1484 	write_unlock_irqrestore(&sg_index_lock, iflags);
1485 	kfree(sdp);
1486 
1487 out:
1488 	put_disk(disk);
1489 	if (cdev)
1490 		cdev_del(cdev);
1491 	return error;
1492 }
1493 
1494 static void
1495 sg_remove(struct device *cl_dev, struct class_interface *cl_intf)
1496 {
1497 	struct scsi_device *scsidp = to_scsi_device(cl_dev->parent);
1498 	Sg_device *sdp = dev_get_drvdata(cl_dev);
1499 	unsigned long iflags;
1500 	Sg_fd *sfp;
1501 	Sg_fd *tsfp;
1502 	Sg_request *srp;
1503 	Sg_request *tsrp;
1504 	int delay;
1505 
1506 	if (!sdp)
1507 		return;
1508 
1509 	delay = 0;
1510 	write_lock_irqsave(&sg_index_lock, iflags);
1511 	if (sdp->headfp) {
1512 		sdp->detached = 1;
1513 		for (sfp = sdp->headfp; sfp; sfp = tsfp) {
1514 			tsfp = sfp->nextfp;
1515 			for (srp = sfp->headrp; srp; srp = tsrp) {
1516 				tsrp = srp->nextrp;
1517 				if (sfp->closed || (0 == sg_srp_done(srp, sfp)))
1518 					sg_finish_rem_req(srp);
1519 			}
1520 			if (sfp->closed) {
1521 				scsi_device_put(sdp->device);
1522 				__sg_remove_sfp(sdp, sfp);
1523 			} else {
1524 				delay = 1;
1525 				wake_up_interruptible(&sfp->read_wait);
1526 				kill_fasync(&sfp->async_qp, SIGPOLL,
1527 					    POLL_HUP);
1528 			}
1529 		}
1530 		SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d, dirty\n", sdp->index));
1531 		if (NULL == sdp->headfp) {
1532 			idr_remove(&sg_index_idr, sdp->index);
1533 		}
1534 	} else {	/* nothing active, simple case */
1535 		SCSI_LOG_TIMEOUT(3, printk("sg_remove: dev=%d\n", sdp->index));
1536 		idr_remove(&sg_index_idr, sdp->index);
1537 	}
1538 	write_unlock_irqrestore(&sg_index_lock, iflags);
1539 
1540 	sysfs_remove_link(&scsidp->sdev_gendev.kobj, "generic");
1541 	device_destroy(sg_sysfs_class, MKDEV(SCSI_GENERIC_MAJOR, sdp->index));
1542 	cdev_del(sdp->cdev);
1543 	sdp->cdev = NULL;
1544 	put_disk(sdp->disk);
1545 	sdp->disk = NULL;
1546 	if (NULL == sdp->headfp)
1547 		kfree(sdp);
1548 
1549 	if (delay)
1550 		msleep(10);	/* dirty detach so delay device destruction */
1551 }
1552 
1553 module_param_named(scatter_elem_sz, scatter_elem_sz, int, S_IRUGO | S_IWUSR);
1554 module_param_named(def_reserved_size, def_reserved_size, int,
1555 		   S_IRUGO | S_IWUSR);
1556 module_param_named(allow_dio, sg_allow_dio, int, S_IRUGO | S_IWUSR);
1557 
1558 MODULE_AUTHOR("Douglas Gilbert");
1559 MODULE_DESCRIPTION("SCSI generic (sg) driver");
1560 MODULE_LICENSE("GPL");
1561 MODULE_VERSION(SG_VERSION_STR);
1562 MODULE_ALIAS_CHARDEV_MAJOR(SCSI_GENERIC_MAJOR);
1563 
1564 MODULE_PARM_DESC(scatter_elem_sz, "scatter gather element "
1565                 "size (default: max(SG_SCATTER_SZ, PAGE_SIZE))");
1566 MODULE_PARM_DESC(def_reserved_size, "size of buffer reserved for each fd");
1567 MODULE_PARM_DESC(allow_dio, "allow direct I/O (default: 0 (disallow))");
1568 
1569 static int __init
1570 init_sg(void)
1571 {
1572 	int rc;
1573 
1574 	if (scatter_elem_sz < PAGE_SIZE) {
1575 		scatter_elem_sz = PAGE_SIZE;
1576 		scatter_elem_sz_prev = scatter_elem_sz;
1577 	}
1578 	if (def_reserved_size >= 0)
1579 		sg_big_buff = def_reserved_size;
1580 	else
1581 		def_reserved_size = sg_big_buff;
1582 
1583 	rc = register_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1584 				    SG_MAX_DEVS, "sg");
1585 	if (rc)
1586 		return rc;
1587         sg_sysfs_class = class_create(THIS_MODULE, "scsi_generic");
1588         if ( IS_ERR(sg_sysfs_class) ) {
1589 		rc = PTR_ERR(sg_sysfs_class);
1590 		goto err_out;
1591         }
1592 	sg_sysfs_valid = 1;
1593 	rc = scsi_register_interface(&sg_interface);
1594 	if (0 == rc) {
1595 #ifdef CONFIG_SCSI_PROC_FS
1596 		sg_proc_init();
1597 #endif				/* CONFIG_SCSI_PROC_FS */
1598 		return 0;
1599 	}
1600 	class_destroy(sg_sysfs_class);
1601 err_out:
1602 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0), SG_MAX_DEVS);
1603 	return rc;
1604 }
1605 
1606 static void __exit
1607 exit_sg(void)
1608 {
1609 #ifdef CONFIG_SCSI_PROC_FS
1610 	sg_proc_cleanup();
1611 #endif				/* CONFIG_SCSI_PROC_FS */
1612 	scsi_unregister_interface(&sg_interface);
1613 	class_destroy(sg_sysfs_class);
1614 	sg_sysfs_valid = 0;
1615 	unregister_chrdev_region(MKDEV(SCSI_GENERIC_MAJOR, 0),
1616 				 SG_MAX_DEVS);
1617 	idr_destroy(&sg_index_idr);
1618 }
1619 
1620 static int sg_start_req(Sg_request *srp, unsigned char *cmd)
1621 {
1622 	int res;
1623 	struct request *rq;
1624 	Sg_fd *sfp = srp->parentfp;
1625 	sg_io_hdr_t *hp = &srp->header;
1626 	int dxfer_len = (int) hp->dxfer_len;
1627 	int dxfer_dir = hp->dxfer_direction;
1628 	unsigned int iov_count = hp->iovec_count;
1629 	Sg_scatter_hold *req_schp = &srp->data;
1630 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1631 	struct request_queue *q = sfp->parentdp->device->request_queue;
1632 	struct rq_map_data *md, map_data;
1633 	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
1634 
1635 	SCSI_LOG_TIMEOUT(4, printk(KERN_INFO "sg_start_req: dxfer_len=%d\n",
1636 				   dxfer_len));
1637 
1638 	rq = blk_get_request(q, rw, GFP_ATOMIC);
1639 	if (!rq)
1640 		return -ENOMEM;
1641 
1642 	memcpy(rq->cmd, cmd, hp->cmd_len);
1643 
1644 	rq->cmd_len = hp->cmd_len;
1645 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
1646 
1647 	srp->rq = rq;
1648 	rq->end_io_data = srp;
1649 	rq->sense = srp->sense_b;
1650 	rq->retries = SG_DEFAULT_RETRIES;
1651 
1652 	if ((dxfer_len <= 0) || (dxfer_dir == SG_DXFER_NONE))
1653 		return 0;
1654 
1655 	if (sg_allow_dio && hp->flags & SG_FLAG_DIRECT_IO &&
1656 	    dxfer_dir != SG_DXFER_UNKNOWN && !iov_count &&
1657 	    !sfp->parentdp->device->host->unchecked_isa_dma &&
1658 	    blk_rq_aligned(q, hp->dxferp, dxfer_len))
1659 		md = NULL;
1660 	else
1661 		md = &map_data;
1662 
1663 	if (md) {
1664 		if (!sg_res_in_use(sfp) && dxfer_len <= rsv_schp->bufflen)
1665 			sg_link_reserve(sfp, srp, dxfer_len);
1666 		else {
1667 			res = sg_build_indirect(req_schp, sfp, dxfer_len);
1668 			if (res)
1669 				return res;
1670 		}
1671 
1672 		md->pages = req_schp->pages;
1673 		md->page_order = req_schp->page_order;
1674 		md->nr_entries = req_schp->k_use_sg;
1675 	}
1676 
1677 	if (iov_count)
1678 		res = blk_rq_map_user_iov(q, rq, md, hp->dxferp, iov_count,
1679 					  hp->dxfer_len, GFP_ATOMIC);
1680 	else
1681 		res = blk_rq_map_user(q, rq, md, hp->dxferp,
1682 				      hp->dxfer_len, GFP_ATOMIC);
1683 
1684 	if (!res) {
1685 		srp->bio = rq->bio;
1686 
1687 		if (!md) {
1688 			req_schp->dio_in_use = 1;
1689 			hp->info |= SG_INFO_DIRECT_IO;
1690 		}
1691 	}
1692 	return res;
1693 }
1694 
1695 static void
1696 sg_finish_rem_req(Sg_request * srp)
1697 {
1698 	Sg_fd *sfp = srp->parentfp;
1699 	Sg_scatter_hold *req_schp = &srp->data;
1700 
1701 	SCSI_LOG_TIMEOUT(4, printk("sg_finish_rem_req: res_used=%d\n", (int) srp->res_used));
1702 	if (srp->res_used)
1703 		sg_unlink_reserve(sfp, srp);
1704 	else
1705 		sg_remove_scat(req_schp);
1706 
1707 	if (srp->rq) {
1708 		if (srp->bio)
1709 			blk_rq_unmap_user(srp->bio);
1710 
1711 		blk_put_request(srp->rq);
1712 	}
1713 
1714 	sg_remove_request(sfp, srp);
1715 }
1716 
1717 static int
1718 sg_build_sgat(Sg_scatter_hold * schp, const Sg_fd * sfp, int tablesize)
1719 {
1720 	int sg_bufflen = tablesize * sizeof(struct page *);
1721 	gfp_t gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
1722 
1723 	schp->pages = kzalloc(sg_bufflen, gfp_flags);
1724 	if (!schp->pages)
1725 		return -ENOMEM;
1726 	schp->sglist_len = sg_bufflen;
1727 	return tablesize;	/* number of scat_gath elements allocated */
1728 }
1729 
1730 static int
1731 sg_build_indirect(Sg_scatter_hold * schp, Sg_fd * sfp, int buff_size)
1732 {
1733 	int ret_sz = 0, i, k, rem_sz, num, mx_sc_elems;
1734 	int sg_tablesize = sfp->parentdp->sg_tablesize;
1735 	int blk_size = buff_size, order;
1736 	gfp_t gfp_mask = GFP_ATOMIC | __GFP_COMP | __GFP_NOWARN;
1737 
1738 	if (blk_size < 0)
1739 		return -EFAULT;
1740 	if (0 == blk_size)
1741 		++blk_size;	/* don't know why */
1742 /* round request up to next highest SG_SECTOR_SZ byte boundary */
1743 	blk_size = (blk_size + SG_SECTOR_MSK) & (~SG_SECTOR_MSK);
1744 	SCSI_LOG_TIMEOUT(4, printk("sg_build_indirect: buff_size=%d, blk_size=%d\n",
1745 				   buff_size, blk_size));
1746 
1747 	/* N.B. ret_sz carried into this block ... */
1748 	mx_sc_elems = sg_build_sgat(schp, sfp, sg_tablesize);
1749 	if (mx_sc_elems < 0)
1750 		return mx_sc_elems;	/* most likely -ENOMEM */
1751 
1752 	num = scatter_elem_sz;
1753 	if (unlikely(num != scatter_elem_sz_prev)) {
1754 		if (num < PAGE_SIZE) {
1755 			scatter_elem_sz = PAGE_SIZE;
1756 			scatter_elem_sz_prev = PAGE_SIZE;
1757 		} else
1758 			scatter_elem_sz_prev = num;
1759 	}
1760 
1761 	if (sfp->low_dma)
1762 		gfp_mask |= GFP_DMA;
1763 
1764 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
1765 		gfp_mask |= __GFP_ZERO;
1766 
1767 	order = get_order(num);
1768 retry:
1769 	ret_sz = 1 << (PAGE_SHIFT + order);
1770 
1771 	for (k = 0, rem_sz = blk_size; rem_sz > 0 && k < mx_sc_elems;
1772 	     k++, rem_sz -= ret_sz) {
1773 
1774 		num = (rem_sz > scatter_elem_sz_prev) ?
1775 			scatter_elem_sz_prev : rem_sz;
1776 
1777 		schp->pages[k] = alloc_pages(gfp_mask, order);
1778 		if (!schp->pages[k])
1779 			goto out;
1780 
1781 		if (num == scatter_elem_sz_prev) {
1782 			if (unlikely(ret_sz > scatter_elem_sz_prev)) {
1783 				scatter_elem_sz = ret_sz;
1784 				scatter_elem_sz_prev = ret_sz;
1785 			}
1786 		}
1787 
1788 		SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k=%d, num=%d, "
1789 				 "ret_sz=%d\n", k, num, ret_sz));
1790 	}		/* end of for loop */
1791 
1792 	schp->page_order = order;
1793 	schp->k_use_sg = k;
1794 	SCSI_LOG_TIMEOUT(5, printk("sg_build_indirect: k_use_sg=%d, "
1795 			 "rem_sz=%d\n", k, rem_sz));
1796 
1797 	schp->bufflen = blk_size;
1798 	if (rem_sz > 0)	/* must have failed */
1799 		return -ENOMEM;
1800 	return 0;
1801 out:
1802 	for (i = 0; i < k; i++)
1803 		__free_pages(schp->pages[k], order);
1804 
1805 	if (--order >= 0)
1806 		goto retry;
1807 
1808 	return -ENOMEM;
1809 }
1810 
1811 static void
1812 sg_remove_scat(Sg_scatter_hold * schp)
1813 {
1814 	SCSI_LOG_TIMEOUT(4, printk("sg_remove_scat: k_use_sg=%d\n", schp->k_use_sg));
1815 	if (schp->pages && schp->sglist_len > 0) {
1816 		if (!schp->dio_in_use) {
1817 			int k;
1818 
1819 			for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1820 				SCSI_LOG_TIMEOUT(5, printk(
1821 				    "sg_remove_scat: k=%d, pg=0x%p\n",
1822 				    k, schp->pages[k]));
1823 				__free_pages(schp->pages[k], schp->page_order);
1824 			}
1825 
1826 			kfree(schp->pages);
1827 		}
1828 	}
1829 	memset(schp, 0, sizeof (*schp));
1830 }
1831 
1832 static int
1833 sg_read_oxfer(Sg_request * srp, char __user *outp, int num_read_xfer)
1834 {
1835 	Sg_scatter_hold *schp = &srp->data;
1836 	int k, num;
1837 
1838 	SCSI_LOG_TIMEOUT(4, printk("sg_read_oxfer: num_read_xfer=%d\n",
1839 				   num_read_xfer));
1840 	if ((!outp) || (num_read_xfer <= 0))
1841 		return 0;
1842 
1843 	num = 1 << (PAGE_SHIFT + schp->page_order);
1844 	for (k = 0; k < schp->k_use_sg && schp->pages[k]; k++) {
1845 		if (num > num_read_xfer) {
1846 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1847 					   num_read_xfer))
1848 				return -EFAULT;
1849 			break;
1850 		} else {
1851 			if (__copy_to_user(outp, page_address(schp->pages[k]),
1852 					   num))
1853 				return -EFAULT;
1854 			num_read_xfer -= num;
1855 			if (num_read_xfer <= 0)
1856 				break;
1857 			outp += num;
1858 		}
1859 	}
1860 
1861 	return 0;
1862 }
1863 
1864 static void
1865 sg_build_reserve(Sg_fd * sfp, int req_size)
1866 {
1867 	Sg_scatter_hold *schp = &sfp->reserve;
1868 
1869 	SCSI_LOG_TIMEOUT(4, printk("sg_build_reserve: req_size=%d\n", req_size));
1870 	do {
1871 		if (req_size < PAGE_SIZE)
1872 			req_size = PAGE_SIZE;
1873 		if (0 == sg_build_indirect(schp, sfp, req_size))
1874 			return;
1875 		else
1876 			sg_remove_scat(schp);
1877 		req_size >>= 1;	/* divide by 2 */
1878 	} while (req_size > (PAGE_SIZE / 2));
1879 }
1880 
1881 static void
1882 sg_link_reserve(Sg_fd * sfp, Sg_request * srp, int size)
1883 {
1884 	Sg_scatter_hold *req_schp = &srp->data;
1885 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
1886 	int k, num, rem;
1887 
1888 	srp->res_used = 1;
1889 	SCSI_LOG_TIMEOUT(4, printk("sg_link_reserve: size=%d\n", size));
1890 	rem = size;
1891 
1892 	num = 1 << (PAGE_SHIFT + rsv_schp->page_order);
1893 	for (k = 0; k < rsv_schp->k_use_sg; k++) {
1894 		if (rem <= num) {
1895 			req_schp->k_use_sg = k + 1;
1896 			req_schp->sglist_len = rsv_schp->sglist_len;
1897 			req_schp->pages = rsv_schp->pages;
1898 
1899 			req_schp->bufflen = size;
1900 			req_schp->page_order = rsv_schp->page_order;
1901 			break;
1902 		} else
1903 			rem -= num;
1904 	}
1905 
1906 	if (k >= rsv_schp->k_use_sg)
1907 		SCSI_LOG_TIMEOUT(1, printk("sg_link_reserve: BAD size\n"));
1908 }
1909 
1910 static void
1911 sg_unlink_reserve(Sg_fd * sfp, Sg_request * srp)
1912 {
1913 	Sg_scatter_hold *req_schp = &srp->data;
1914 
1915 	SCSI_LOG_TIMEOUT(4, printk("sg_unlink_reserve: req->k_use_sg=%d\n",
1916 				   (int) req_schp->k_use_sg));
1917 	req_schp->k_use_sg = 0;
1918 	req_schp->bufflen = 0;
1919 	req_schp->pages = NULL;
1920 	req_schp->page_order = 0;
1921 	req_schp->sglist_len = 0;
1922 	sfp->save_scat_len = 0;
1923 	srp->res_used = 0;
1924 }
1925 
1926 static Sg_request *
1927 sg_get_rq_mark(Sg_fd * sfp, int pack_id)
1928 {
1929 	Sg_request *resp;
1930 	unsigned long iflags;
1931 
1932 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1933 	for (resp = sfp->headrp; resp; resp = resp->nextrp) {
1934 		/* look for requests that are ready + not SG_IO owned */
1935 		if ((1 == resp->done) && (!resp->sg_io_owned) &&
1936 		    ((-1 == pack_id) || (resp->header.pack_id == pack_id))) {
1937 			resp->done = 2;	/* guard against other readers */
1938 			break;
1939 		}
1940 	}
1941 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1942 	return resp;
1943 }
1944 
1945 #ifdef CONFIG_SCSI_PROC_FS
1946 static Sg_request *
1947 sg_get_nth_request(Sg_fd * sfp, int nth)
1948 {
1949 	Sg_request *resp;
1950 	unsigned long iflags;
1951 	int k;
1952 
1953 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
1954 	for (k = 0, resp = sfp->headrp; resp && (k < nth);
1955 	     ++k, resp = resp->nextrp) ;
1956 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
1957 	return resp;
1958 }
1959 #endif
1960 
1961 /* always adds to end of list */
1962 static Sg_request *
1963 sg_add_request(Sg_fd * sfp)
1964 {
1965 	int k;
1966 	unsigned long iflags;
1967 	Sg_request *resp;
1968 	Sg_request *rp = sfp->req_arr;
1969 
1970 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
1971 	resp = sfp->headrp;
1972 	if (!resp) {
1973 		memset(rp, 0, sizeof (Sg_request));
1974 		rp->parentfp = sfp;
1975 		resp = rp;
1976 		sfp->headrp = resp;
1977 	} else {
1978 		if (0 == sfp->cmd_q)
1979 			resp = NULL;	/* command queuing disallowed */
1980 		else {
1981 			for (k = 0; k < SG_MAX_QUEUE; ++k, ++rp) {
1982 				if (!rp->parentfp)
1983 					break;
1984 			}
1985 			if (k < SG_MAX_QUEUE) {
1986 				memset(rp, 0, sizeof (Sg_request));
1987 				rp->parentfp = sfp;
1988 				while (resp->nextrp)
1989 					resp = resp->nextrp;
1990 				resp->nextrp = rp;
1991 				resp = rp;
1992 			} else
1993 				resp = NULL;
1994 		}
1995 	}
1996 	if (resp) {
1997 		resp->nextrp = NULL;
1998 		resp->header.duration = jiffies_to_msecs(jiffies);
1999 	}
2000 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2001 	return resp;
2002 }
2003 
2004 /* Return of 1 for found; 0 for not found */
2005 static int
2006 sg_remove_request(Sg_fd * sfp, Sg_request * srp)
2007 {
2008 	Sg_request *prev_rp;
2009 	Sg_request *rp;
2010 	unsigned long iflags;
2011 	int res = 0;
2012 
2013 	if ((!sfp) || (!srp) || (!sfp->headrp))
2014 		return res;
2015 	write_lock_irqsave(&sfp->rq_list_lock, iflags);
2016 	prev_rp = sfp->headrp;
2017 	if (srp == prev_rp) {
2018 		sfp->headrp = prev_rp->nextrp;
2019 		prev_rp->parentfp = NULL;
2020 		res = 1;
2021 	} else {
2022 		while ((rp = prev_rp->nextrp)) {
2023 			if (srp == rp) {
2024 				prev_rp->nextrp = rp->nextrp;
2025 				rp->parentfp = NULL;
2026 				res = 1;
2027 				break;
2028 			}
2029 			prev_rp = rp;
2030 		}
2031 	}
2032 	write_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2033 	return res;
2034 }
2035 
2036 #ifdef CONFIG_SCSI_PROC_FS
2037 static Sg_fd *
2038 sg_get_nth_sfp(Sg_device * sdp, int nth)
2039 {
2040 	Sg_fd *resp;
2041 	unsigned long iflags;
2042 	int k;
2043 
2044 	read_lock_irqsave(&sg_index_lock, iflags);
2045 	for (k = 0, resp = sdp->headfp; resp && (k < nth);
2046 	     ++k, resp = resp->nextfp) ;
2047 	read_unlock_irqrestore(&sg_index_lock, iflags);
2048 	return resp;
2049 }
2050 #endif
2051 
2052 static Sg_fd *
2053 sg_add_sfp(Sg_device * sdp, int dev)
2054 {
2055 	Sg_fd *sfp;
2056 	unsigned long iflags;
2057 	int bufflen;
2058 
2059 	sfp = kzalloc(sizeof(*sfp), GFP_ATOMIC | __GFP_NOWARN);
2060 	if (!sfp)
2061 		return NULL;
2062 
2063 	init_waitqueue_head(&sfp->read_wait);
2064 	rwlock_init(&sfp->rq_list_lock);
2065 
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 	if (!sdp->headfp)
2076 		sdp->headfp = sfp;
2077 	else {			/* add to tail of existing list */
2078 		Sg_fd *pfp = sdp->headfp;
2079 		while (pfp->nextfp)
2080 			pfp = pfp->nextfp;
2081 		pfp->nextfp = sfp;
2082 	}
2083 	write_unlock_irqrestore(&sg_index_lock, iflags);
2084 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp: sfp=0x%p\n", sfp));
2085 	if (unlikely(sg_big_buff != def_reserved_size))
2086 		sg_big_buff = def_reserved_size;
2087 
2088 	bufflen = min_t(int, sg_big_buff,
2089 			sdp->device->request_queue->max_sectors * 512);
2090 	sg_build_reserve(sfp, bufflen);
2091 	SCSI_LOG_TIMEOUT(3, printk("sg_add_sfp:   bufflen=%d, k_use_sg=%d\n",
2092 			   sfp->reserve.bufflen, sfp->reserve.k_use_sg));
2093 	return sfp;
2094 }
2095 
2096 static void
2097 __sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2098 {
2099 	Sg_fd *fp;
2100 	Sg_fd *prev_fp;
2101 
2102 	prev_fp = sdp->headfp;
2103 	if (sfp == prev_fp)
2104 		sdp->headfp = prev_fp->nextfp;
2105 	else {
2106 		while ((fp = prev_fp->nextfp)) {
2107 			if (sfp == fp) {
2108 				prev_fp->nextfp = fp->nextfp;
2109 				break;
2110 			}
2111 			prev_fp = fp;
2112 		}
2113 	}
2114 	if (sfp->reserve.bufflen > 0) {
2115 		SCSI_LOG_TIMEOUT(6,
2116 			printk("__sg_remove_sfp:    bufflen=%d, k_use_sg=%d\n",
2117 			(int) sfp->reserve.bufflen, (int) sfp->reserve.k_use_sg));
2118 		sg_remove_scat(&sfp->reserve);
2119 	}
2120 	sfp->parentdp = NULL;
2121 	SCSI_LOG_TIMEOUT(6, printk("__sg_remove_sfp:    sfp=0x%p\n", sfp));
2122 	kfree(sfp);
2123 }
2124 
2125 /* Returns 0 in normal case, 1 when detached and sdp object removed */
2126 static int
2127 sg_remove_sfp(Sg_device * sdp, Sg_fd * sfp)
2128 {
2129 	Sg_request *srp;
2130 	Sg_request *tsrp;
2131 	int dirty = 0;
2132 	int res = 0;
2133 
2134 	for (srp = sfp->headrp; srp; srp = tsrp) {
2135 		tsrp = srp->nextrp;
2136 		if (sg_srp_done(srp, sfp))
2137 			sg_finish_rem_req(srp);
2138 		else
2139 			++dirty;
2140 	}
2141 	if (0 == dirty) {
2142 		unsigned long iflags;
2143 
2144 		write_lock_irqsave(&sg_index_lock, iflags);
2145 		__sg_remove_sfp(sdp, sfp);
2146 		if (sdp->detached && (NULL == sdp->headfp)) {
2147 			idr_remove(&sg_index_idr, sdp->index);
2148 			kfree(sdp);
2149 			res = 1;
2150 		}
2151 		write_unlock_irqrestore(&sg_index_lock, iflags);
2152 	} else {
2153 		/* MOD_INC's to inhibit unloading sg and associated adapter driver */
2154 		/* only bump the access_count if we actually succeeded in
2155 		 * throwing another counter on the host module */
2156 		scsi_device_get(sdp->device);	/* XXX: retval ignored? */
2157 		sfp->closed = 1;	/* flag dirty state on this fd */
2158 		SCSI_LOG_TIMEOUT(1, printk("sg_remove_sfp: worrisome, %d writes pending\n",
2159 				  dirty));
2160 	}
2161 	return res;
2162 }
2163 
2164 static int
2165 sg_res_in_use(Sg_fd * sfp)
2166 {
2167 	const Sg_request *srp;
2168 	unsigned long iflags;
2169 
2170 	read_lock_irqsave(&sfp->rq_list_lock, iflags);
2171 	for (srp = sfp->headrp; srp; srp = srp->nextrp)
2172 		if (srp->res_used)
2173 			break;
2174 	read_unlock_irqrestore(&sfp->rq_list_lock, iflags);
2175 	return srp ? 1 : 0;
2176 }
2177 
2178 #ifdef CONFIG_SCSI_PROC_FS
2179 static int
2180 sg_idr_max_id(int id, void *p, void *data)
2181 {
2182 	int *k = data;
2183 
2184 	if (*k < id)
2185 		*k = id;
2186 
2187 	return 0;
2188 }
2189 
2190 static int
2191 sg_last_dev(void)
2192 {
2193 	int k = -1;
2194 	unsigned long iflags;
2195 
2196 	read_lock_irqsave(&sg_index_lock, iflags);
2197 	idr_for_each(&sg_index_idr, sg_idr_max_id, &k);
2198 	read_unlock_irqrestore(&sg_index_lock, iflags);
2199 	return k + 1;		/* origin 1 */
2200 }
2201 #endif
2202 
2203 static Sg_device *
2204 sg_get_dev(int dev)
2205 {
2206 	Sg_device *sdp;
2207 	unsigned long iflags;
2208 
2209 	read_lock_irqsave(&sg_index_lock, iflags);
2210 	sdp = idr_find(&sg_index_idr, dev);
2211 	read_unlock_irqrestore(&sg_index_lock, iflags);
2212 
2213 	return sdp;
2214 }
2215 
2216 #ifdef CONFIG_SCSI_PROC_FS
2217 
2218 static struct proc_dir_entry *sg_proc_sgp = NULL;
2219 
2220 static char sg_proc_sg_dirname[] = "scsi/sg";
2221 
2222 static int sg_proc_seq_show_int(struct seq_file *s, void *v);
2223 
2224 static int sg_proc_single_open_adio(struct inode *inode, struct file *file);
2225 static ssize_t sg_proc_write_adio(struct file *filp, const char __user *buffer,
2226 			          size_t count, loff_t *off);
2227 static struct file_operations adio_fops = {
2228 	/* .owner, .read and .llseek added in sg_proc_init() */
2229 	.open = sg_proc_single_open_adio,
2230 	.write = sg_proc_write_adio,
2231 	.release = single_release,
2232 };
2233 
2234 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file);
2235 static ssize_t sg_proc_write_dressz(struct file *filp,
2236 		const char __user *buffer, size_t count, loff_t *off);
2237 static struct file_operations dressz_fops = {
2238 	.open = sg_proc_single_open_dressz,
2239 	.write = sg_proc_write_dressz,
2240 	.release = single_release,
2241 };
2242 
2243 static int sg_proc_seq_show_version(struct seq_file *s, void *v);
2244 static int sg_proc_single_open_version(struct inode *inode, struct file *file);
2245 static struct file_operations version_fops = {
2246 	.open = sg_proc_single_open_version,
2247 	.release = single_release,
2248 };
2249 
2250 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v);
2251 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file);
2252 static struct file_operations devhdr_fops = {
2253 	.open = sg_proc_single_open_devhdr,
2254 	.release = single_release,
2255 };
2256 
2257 static int sg_proc_seq_show_dev(struct seq_file *s, void *v);
2258 static int sg_proc_open_dev(struct inode *inode, struct file *file);
2259 static void * dev_seq_start(struct seq_file *s, loff_t *pos);
2260 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos);
2261 static void dev_seq_stop(struct seq_file *s, void *v);
2262 static struct file_operations dev_fops = {
2263 	.open = sg_proc_open_dev,
2264 	.release = seq_release,
2265 };
2266 static struct seq_operations dev_seq_ops = {
2267 	.start = dev_seq_start,
2268 	.next  = dev_seq_next,
2269 	.stop  = dev_seq_stop,
2270 	.show  = sg_proc_seq_show_dev,
2271 };
2272 
2273 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v);
2274 static int sg_proc_open_devstrs(struct inode *inode, struct file *file);
2275 static struct file_operations devstrs_fops = {
2276 	.open = sg_proc_open_devstrs,
2277 	.release = seq_release,
2278 };
2279 static struct seq_operations devstrs_seq_ops = {
2280 	.start = dev_seq_start,
2281 	.next  = dev_seq_next,
2282 	.stop  = dev_seq_stop,
2283 	.show  = sg_proc_seq_show_devstrs,
2284 };
2285 
2286 static int sg_proc_seq_show_debug(struct seq_file *s, void *v);
2287 static int sg_proc_open_debug(struct inode *inode, struct file *file);
2288 static struct file_operations debug_fops = {
2289 	.open = sg_proc_open_debug,
2290 	.release = seq_release,
2291 };
2292 static struct seq_operations debug_seq_ops = {
2293 	.start = dev_seq_start,
2294 	.next  = dev_seq_next,
2295 	.stop  = dev_seq_stop,
2296 	.show  = sg_proc_seq_show_debug,
2297 };
2298 
2299 
2300 struct sg_proc_leaf {
2301 	const char * name;
2302 	struct file_operations * fops;
2303 };
2304 
2305 static struct sg_proc_leaf sg_proc_leaf_arr[] = {
2306 	{"allow_dio", &adio_fops},
2307 	{"debug", &debug_fops},
2308 	{"def_reserved_size", &dressz_fops},
2309 	{"device_hdr", &devhdr_fops},
2310 	{"devices", &dev_fops},
2311 	{"device_strs", &devstrs_fops},
2312 	{"version", &version_fops}
2313 };
2314 
2315 static int
2316 sg_proc_init(void)
2317 {
2318 	int k, mask;
2319 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2320 	struct sg_proc_leaf * leaf;
2321 
2322 	sg_proc_sgp = proc_mkdir(sg_proc_sg_dirname, NULL);
2323 	if (!sg_proc_sgp)
2324 		return 1;
2325 	for (k = 0; k < num_leaves; ++k) {
2326 		leaf = &sg_proc_leaf_arr[k];
2327 		mask = leaf->fops->write ? S_IRUGO | S_IWUSR : S_IRUGO;
2328 		leaf->fops->owner = THIS_MODULE;
2329 		leaf->fops->read = seq_read;
2330 		leaf->fops->llseek = seq_lseek;
2331 		proc_create(leaf->name, mask, sg_proc_sgp, leaf->fops);
2332 	}
2333 	return 0;
2334 }
2335 
2336 static void
2337 sg_proc_cleanup(void)
2338 {
2339 	int k;
2340 	int num_leaves = ARRAY_SIZE(sg_proc_leaf_arr);
2341 
2342 	if (!sg_proc_sgp)
2343 		return;
2344 	for (k = 0; k < num_leaves; ++k)
2345 		remove_proc_entry(sg_proc_leaf_arr[k].name, sg_proc_sgp);
2346 	remove_proc_entry(sg_proc_sg_dirname, NULL);
2347 }
2348 
2349 
2350 static int sg_proc_seq_show_int(struct seq_file *s, void *v)
2351 {
2352 	seq_printf(s, "%d\n", *((int *)s->private));
2353 	return 0;
2354 }
2355 
2356 static int sg_proc_single_open_adio(struct inode *inode, struct file *file)
2357 {
2358 	return single_open(file, sg_proc_seq_show_int, &sg_allow_dio);
2359 }
2360 
2361 static ssize_t
2362 sg_proc_write_adio(struct file *filp, const char __user *buffer,
2363 		   size_t count, loff_t *off)
2364 {
2365 	int num;
2366 	char buff[11];
2367 
2368 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2369 		return -EACCES;
2370 	num = (count < 10) ? count : 10;
2371 	if (copy_from_user(buff, buffer, num))
2372 		return -EFAULT;
2373 	buff[num] = '\0';
2374 	sg_allow_dio = simple_strtoul(buff, NULL, 10) ? 1 : 0;
2375 	return count;
2376 }
2377 
2378 static int sg_proc_single_open_dressz(struct inode *inode, struct file *file)
2379 {
2380 	return single_open(file, sg_proc_seq_show_int, &sg_big_buff);
2381 }
2382 
2383 static ssize_t
2384 sg_proc_write_dressz(struct file *filp, const char __user *buffer,
2385 		     size_t count, loff_t *off)
2386 {
2387 	int num;
2388 	unsigned long k = ULONG_MAX;
2389 	char buff[11];
2390 
2391 	if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
2392 		return -EACCES;
2393 	num = (count < 10) ? count : 10;
2394 	if (copy_from_user(buff, buffer, num))
2395 		return -EFAULT;
2396 	buff[num] = '\0';
2397 	k = simple_strtoul(buff, NULL, 10);
2398 	if (k <= 1048576) {	/* limit "big buff" to 1 MB */
2399 		sg_big_buff = k;
2400 		return count;
2401 	}
2402 	return -ERANGE;
2403 }
2404 
2405 static int sg_proc_seq_show_version(struct seq_file *s, void *v)
2406 {
2407 	seq_printf(s, "%d\t%s [%s]\n", sg_version_num, SG_VERSION_STR,
2408 		   sg_version_date);
2409 	return 0;
2410 }
2411 
2412 static int sg_proc_single_open_version(struct inode *inode, struct file *file)
2413 {
2414 	return single_open(file, sg_proc_seq_show_version, NULL);
2415 }
2416 
2417 static int sg_proc_seq_show_devhdr(struct seq_file *s, void *v)
2418 {
2419 	seq_printf(s, "host\tchan\tid\tlun\ttype\topens\tqdepth\tbusy\t"
2420 		   "online\n");
2421 	return 0;
2422 }
2423 
2424 static int sg_proc_single_open_devhdr(struct inode *inode, struct file *file)
2425 {
2426 	return single_open(file, sg_proc_seq_show_devhdr, NULL);
2427 }
2428 
2429 struct sg_proc_deviter {
2430 	loff_t	index;
2431 	size_t	max;
2432 };
2433 
2434 static void * dev_seq_start(struct seq_file *s, loff_t *pos)
2435 {
2436 	struct sg_proc_deviter * it = kmalloc(sizeof(*it), GFP_KERNEL);
2437 
2438 	s->private = it;
2439 	if (! it)
2440 		return NULL;
2441 
2442 	it->index = *pos;
2443 	it->max = sg_last_dev();
2444 	if (it->index >= it->max)
2445 		return NULL;
2446 	return it;
2447 }
2448 
2449 static void * dev_seq_next(struct seq_file *s, void *v, loff_t *pos)
2450 {
2451 	struct sg_proc_deviter * it = s->private;
2452 
2453 	*pos = ++it->index;
2454 	return (it->index < it->max) ? it : NULL;
2455 }
2456 
2457 static void dev_seq_stop(struct seq_file *s, void *v)
2458 {
2459 	kfree(s->private);
2460 }
2461 
2462 static int sg_proc_open_dev(struct inode *inode, struct file *file)
2463 {
2464         return seq_open(file, &dev_seq_ops);
2465 }
2466 
2467 static int sg_proc_seq_show_dev(struct seq_file *s, void *v)
2468 {
2469 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2470 	Sg_device *sdp;
2471 	struct scsi_device *scsidp;
2472 
2473 	sdp = it ? sg_get_dev(it->index) : NULL;
2474 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2475 		seq_printf(s, "%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
2476 			      scsidp->host->host_no, scsidp->channel,
2477 			      scsidp->id, scsidp->lun, (int) scsidp->type,
2478 			      1,
2479 			      (int) scsidp->queue_depth,
2480 			      (int) scsidp->device_busy,
2481 			      (int) scsi_device_online(scsidp));
2482 	else
2483 		seq_printf(s, "-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\t-1\n");
2484 	return 0;
2485 }
2486 
2487 static int sg_proc_open_devstrs(struct inode *inode, struct file *file)
2488 {
2489         return seq_open(file, &devstrs_seq_ops);
2490 }
2491 
2492 static int sg_proc_seq_show_devstrs(struct seq_file *s, void *v)
2493 {
2494 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2495 	Sg_device *sdp;
2496 	struct scsi_device *scsidp;
2497 
2498 	sdp = it ? sg_get_dev(it->index) : NULL;
2499 	if (sdp && (scsidp = sdp->device) && (!sdp->detached))
2500 		seq_printf(s, "%8.8s\t%16.16s\t%4.4s\n",
2501 			   scsidp->vendor, scsidp->model, scsidp->rev);
2502 	else
2503 		seq_printf(s, "<no active device>\n");
2504 	return 0;
2505 }
2506 
2507 static void sg_proc_debug_helper(struct seq_file *s, Sg_device * sdp)
2508 {
2509 	int k, m, new_interface, blen, usg;
2510 	Sg_request *srp;
2511 	Sg_fd *fp;
2512 	const sg_io_hdr_t *hp;
2513 	const char * cp;
2514 	unsigned int ms;
2515 
2516 	for (k = 0; (fp = sg_get_nth_sfp(sdp, k)); ++k) {
2517 		seq_printf(s, "   FD(%d): timeout=%dms bufflen=%d "
2518 			   "(res)sgat=%d low_dma=%d\n", k + 1,
2519 			   jiffies_to_msecs(fp->timeout),
2520 			   fp->reserve.bufflen,
2521 			   (int) fp->reserve.k_use_sg,
2522 			   (int) fp->low_dma);
2523 		seq_printf(s, "   cmd_q=%d f_packid=%d k_orphan=%d closed=%d\n",
2524 			   (int) fp->cmd_q, (int) fp->force_packid,
2525 			   (int) fp->keep_orphan, (int) fp->closed);
2526 		for (m = 0; (srp = sg_get_nth_request(fp, m)); ++m) {
2527 			hp = &srp->header;
2528 			new_interface = (hp->interface_id == '\0') ? 0 : 1;
2529 			if (srp->res_used) {
2530 				if (new_interface &&
2531 				    (SG_FLAG_MMAP_IO & hp->flags))
2532 					cp = "     mmap>> ";
2533 				else
2534 					cp = "     rb>> ";
2535 			} else {
2536 				if (SG_INFO_DIRECT_IO_MASK & hp->info)
2537 					cp = "     dio>> ";
2538 				else
2539 					cp = "     ";
2540 			}
2541 			seq_printf(s, cp);
2542 			blen = srp->data.bufflen;
2543 			usg = srp->data.k_use_sg;
2544 			seq_printf(s, srp->done ?
2545 				   ((1 == srp->done) ?  "rcv:" : "fin:")
2546 				   : "act:");
2547 			seq_printf(s, " id=%d blen=%d",
2548 				   srp->header.pack_id, blen);
2549 			if (srp->done)
2550 				seq_printf(s, " dur=%d", hp->duration);
2551 			else {
2552 				ms = jiffies_to_msecs(jiffies);
2553 				seq_printf(s, " t_o/elap=%d/%d",
2554 					(new_interface ? hp->timeout :
2555 						  jiffies_to_msecs(fp->timeout)),
2556 					(ms > hp->duration ? ms - hp->duration : 0));
2557 			}
2558 			seq_printf(s, "ms sgat=%d op=0x%02x\n", usg,
2559 				   (int) srp->data.cmd_opcode);
2560 		}
2561 		if (0 == m)
2562 			seq_printf(s, "     No requests active\n");
2563 	}
2564 }
2565 
2566 static int sg_proc_open_debug(struct inode *inode, struct file *file)
2567 {
2568         return seq_open(file, &debug_seq_ops);
2569 }
2570 
2571 static int sg_proc_seq_show_debug(struct seq_file *s, void *v)
2572 {
2573 	struct sg_proc_deviter * it = (struct sg_proc_deviter *) v;
2574 	Sg_device *sdp;
2575 
2576 	if (it && (0 == it->index)) {
2577 		seq_printf(s, "max_active_device=%d(origin 1)\n",
2578 			   (int)it->max);
2579 		seq_printf(s, " def_reserved_size=%d\n", sg_big_buff);
2580 	}
2581 	sdp = it ? sg_get_dev(it->index) : NULL;
2582 	if (sdp) {
2583 		struct scsi_device *scsidp = sdp->device;
2584 
2585 		if (NULL == scsidp) {
2586 			seq_printf(s, "device %d detached ??\n",
2587 				   (int)it->index);
2588 			return 0;
2589 		}
2590 
2591 		if (sg_get_nth_sfp(sdp, 0)) {
2592 			seq_printf(s, " >>> device=%s ",
2593 				sdp->disk->disk_name);
2594 			if (sdp->detached)
2595 				seq_printf(s, "detached pending close ");
2596 			else
2597 				seq_printf
2598 				    (s, "scsi%d chan=%d id=%d lun=%d   em=%d",
2599 				     scsidp->host->host_no,
2600 				     scsidp->channel, scsidp->id,
2601 				     scsidp->lun,
2602 				     scsidp->host->hostt->emulated);
2603 			seq_printf(s, " sg_tablesize=%d excl=%d\n",
2604 				   sdp->sg_tablesize, sdp->exclude);
2605 		}
2606 		sg_proc_debug_helper(s, sdp);
2607 	}
2608 	return 0;
2609 }
2610 
2611 #endif				/* CONFIG_SCSI_PROC_FS */
2612 
2613 module_init(init_sg);
2614 module_exit(exit_sg);
2615