blk-mq: don't count completed flush data request as inflight in case of quiesce
[linux-block.git] / fs / seq_file.c
CommitLineData
b2441318 1// SPDX-License-Identifier: GPL-2.0
1da177e4
LT
2/*
3 * linux/fs/seq_file.c
4 *
5 * helper functions for making synthetic files from sequences of records.
6 * initial implementation -- AV, Oct 2001.
7 */
8
a3963015
JP
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
09652320 11#include <linux/cache.h>
1da177e4 12#include <linux/fs.h>
630d9c47 13#include <linux/export.h>
1da177e4 14#include <linux/seq_file.h>
058504ed 15#include <linux/vmalloc.h>
1da177e4 16#include <linux/slab.h>
adb37c4c 17#include <linux/cred.h>
058504ed 18#include <linux/mm.h>
37607102 19#include <linux/printk.h>
25c6bb76 20#include <linux/string_helpers.h>
d4d50710 21#include <linux/uio.h>
1da177e4 22
7c0f6ba6 23#include <linux/uaccess.h>
1da177e4
LT
24#include <asm/page.h>
25
09652320
AD
26static struct kmem_cache *seq_file_cache __ro_after_init;
27
e075f591
KH
28static void seq_set_overflow(struct seq_file *m)
29{
30 m->count = m->size;
31}
32
058504ed
HC
33static void *seq_buf_alloc(unsigned long size)
34{
8cae8cd8
ES
35 if (unlikely(size > MAX_RW_COUNT))
36 return NULL;
37
d64d01a1 38 return kvmalloc(size, GFP_KERNEL_ACCOUNT);
058504ed
HC
39}
40
1da177e4
LT
41/**
42 * seq_open - initialize sequential file
43 * @file: file we initialize
44 * @op: method table describing the sequence
45 *
46 * seq_open() sets @file, associating it with a sequence described
47 * by @op. @op->start() sets the iterator up and returns the first
48 * element of sequence. @op->stop() shuts it down. @op->next()
49 * returns the next element of sequence. @op->show() prints element
50 * into the buffer. In case of error ->start() and ->next() return
51 * ERR_PTR(error). In the end of sequence they return %NULL. ->show()
52 * returns 0 in case of success and negative number in case of error.
521b5d0c 53 * Returning SEQ_SKIP means "discard this element and move on".
460b865e
YD
54 * Note: seq_open() will allocate a struct seq_file and store its
55 * pointer in @file->private_data. This pointer should not be modified.
1da177e4 56 */
15ad7cdc 57int seq_open(struct file *file, const struct seq_operations *op)
1da177e4 58{
189f9841
YD
59 struct seq_file *p;
60
61 WARN_ON(file->private_data);
62
09652320 63 p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL);
189f9841
YD
64 if (!p)
65 return -ENOMEM;
66
67 file->private_data = p;
1abe77b0 68
0ac1759a 69 mutex_init(&p->lock);
1da177e4 70 p->op = op;
34dbbcdb
LT
71
72 // No refcounting: the lifetime of 'p' is constrained
73 // to the lifetime of the file.
74 p->file = file;
1da177e4 75
8f19d472
EB
76 /*
77 * seq_files support lseek() and pread(). They do not implement
78 * write() at all, but we clear FMODE_PWRITE here for historical
79 * reasons.
80 *
81 * If a client of seq_files a) implements file.write() and b) wishes to
82 * support pwrite() then that client will need to implement its own
83 * file.open() which calls seq_open() and then sets FMODE_PWRITE.
84 */
85 file->f_mode &= ~FMODE_PWRITE;
1da177e4
LT
86 return 0;
87}
88EXPORT_SYMBOL(seq_open);
89
33da8892
EB
90static int traverse(struct seq_file *m, loff_t offset)
91{
1f4aace6 92 loff_t pos = 0;
33da8892
EB
93 int error = 0;
94 void *p;
95
1f4aace6 96 m->index = 0;
33da8892 97 m->count = m->from = 0;
1f4aace6 98 if (!offset)
33da8892 99 return 0;
1f4aace6 100
33da8892 101 if (!m->buf) {
058504ed 102 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
33da8892
EB
103 if (!m->buf)
104 return -ENOMEM;
105 }
1f4aace6 106 p = m->op->start(m, &m->index);
33da8892
EB
107 while (p) {
108 error = PTR_ERR(p);
109 if (IS_ERR(p))
110 break;
111 error = m->op->show(m, p);
112 if (error < 0)
113 break;
114 if (unlikely(error)) {
115 error = 0;
116 m->count = 0;
117 }
1f33c41c 118 if (seq_has_overflowed(m))
33da8892 119 goto Eoverflow;
6a2aeab5 120 p = m->op->next(m, p, &m->index);
33da8892
EB
121 if (pos + m->count > offset) {
122 m->from = offset - pos;
123 m->count -= m->from;
33da8892
EB
124 break;
125 }
126 pos += m->count;
127 m->count = 0;
1f4aace6 128 if (pos == offset)
33da8892 129 break;
33da8892
EB
130 }
131 m->op->stop(m, p);
132 return error;
133
134Eoverflow:
135 m->op->stop(m, p);
058504ed 136 kvfree(m->buf);
801a7605 137 m->count = 0;
058504ed 138 m->buf = seq_buf_alloc(m->size <<= 1);
33da8892
EB
139 return !m->buf ? -ENOMEM : -EAGAIN;
140}
141
1da177e4
LT
142/**
143 * seq_read - ->read() method for sequential files.
67be2dd1
MW
144 * @file: the file to read from
145 * @buf: the buffer to read to
146 * @size: the maximum number of bytes to read
147 * @ppos: the current position in the file
1da177e4
LT
148 *
149 * Ready-made ->f_op->read()
150 */
151ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
152{
d4d50710
CH
153 struct iovec iov = { .iov_base = buf, .iov_len = size};
154 struct kiocb kiocb;
155 struct iov_iter iter;
156 ssize_t ret;
157
158 init_sync_kiocb(&kiocb, file);
de4eda9d 159 iov_iter_init(&iter, ITER_DEST, &iov, 1, size);
d4d50710
CH
160
161 kiocb.ki_pos = *ppos;
162 ret = seq_read_iter(&kiocb, &iter);
163 *ppos = kiocb.ki_pos;
164 return ret;
165}
166EXPORT_SYMBOL(seq_read);
167
168/*
169 * Ready-made ->f_op->read_iter()
170 */
171ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter)
172{
173 struct seq_file *m = iocb->ki_filp->private_data;
1da177e4 174 size_t copied = 0;
1da177e4
LT
175 size_t n;
176 void *p;
177 int err = 0;
178
4bbf439b
AV
179 if (!iov_iter_count(iter))
180 return 0;
181
0ac1759a 182 mutex_lock(&m->lock);
8f19d472 183
e522751d
TM
184 /*
185 * if request is to read from zero offset, reset iterator to first
186 * record as it might have been already advanced by previous requests
187 */
d4d50710 188 if (iocb->ki_pos == 0) {
e522751d 189 m->index = 0;
cf5eebae
MS
190 m->count = 0;
191 }
e522751d 192
d4d50710
CH
193 /* Don't assume ki_pos is where we left it */
194 if (unlikely(iocb->ki_pos != m->read_pos)) {
195 while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN)
8f19d472
EB
196 ;
197 if (err) {
198 /* With prejudice... */
199 m->read_pos = 0;
8f19d472
EB
200 m->index = 0;
201 m->count = 0;
202 goto Done;
7904ac84 203 } else {
d4d50710 204 m->read_pos = iocb->ki_pos;
8f19d472
EB
205 }
206 }
207
1da177e4
LT
208 /* grab buffer if we didn't have one */
209 if (!m->buf) {
058504ed 210 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
1da177e4
LT
211 if (!m->buf)
212 goto Enomem;
213 }
4bbf439b 214 // something left in the buffer - copy it out first
1da177e4 215 if (m->count) {
4bbf439b 216 n = copy_to_iter(m->buf + m->from, m->count, iter);
1da177e4
LT
217 m->count -= n;
218 m->from += n;
1da177e4 219 copied += n;
4bbf439b 220 if (m->count) // hadn't managed to copy everything
1da177e4
LT
221 goto Done;
222 }
4bbf439b 223 // get a non-empty record in the buffer
1f4aace6
N
224 m->from = 0;
225 p = m->op->start(m, &m->index);
1da177e4 226 while (1) {
1da177e4 227 err = PTR_ERR(p);
4bbf439b 228 if (!p || IS_ERR(p)) // EOF or an error
1da177e4
LT
229 break;
230 err = m->op->show(m, p);
4bbf439b 231 if (err < 0) // hard error
1da177e4 232 break;
4bbf439b 233 if (unlikely(err)) // ->show() says "skip it"
521b5d0c 234 m->count = 0;
4bbf439b 235 if (unlikely(!m->count)) { // empty record
1f4aace6 236 p = m->op->next(m, p, &m->index);
4cdfe84b
AV
237 continue;
238 }
4bbf439b 239 if (!seq_has_overflowed(m)) // got it
1da177e4 240 goto Fill;
4bbf439b 241 // need a bigger buffer
1da177e4 242 m->op->stop(m, p);
058504ed 243 kvfree(m->buf);
801a7605 244 m->count = 0;
058504ed 245 m->buf = seq_buf_alloc(m->size <<= 1);
1da177e4
LT
246 if (!m->buf)
247 goto Enomem;
1f4aace6 248 p = m->op->start(m, &m->index);
1da177e4 249 }
4bbf439b 250 // EOF or an error
1da177e4
LT
251 m->op->stop(m, p);
252 m->count = 0;
253 goto Done;
254Fill:
4bbf439b
AV
255 // one non-empty record is in the buffer; if they want more,
256 // try to fit more in, but in any case we need to advance
257 // the iterator once for every record shown.
1f4aace6 258 while (1) {
1da177e4 259 size_t offs = m->count;
1f4aace6
N
260 loff_t pos = m->index;
261
262 p = m->op->next(m, p, &m->index);
3bfa7e14 263 if (pos == m->index) {
a3963015
JP
264 pr_info_ratelimited("buggy .next function %ps did not update position index\n",
265 m->op->next);
1f4aace6 266 m->index++;
3bfa7e14 267 }
4bbf439b 268 if (!p || IS_ERR(p)) // no next record for us
1da177e4 269 break;
4bbf439b 270 if (m->count >= iov_iter_count(iter))
1f4aace6 271 break;
1da177e4 272 err = m->op->show(m, p);
4bbf439b 273 if (err > 0) { // ->show() says "skip it"
1da177e4 274 m->count = offs;
4bbf439b
AV
275 } else if (err || seq_has_overflowed(m)) {
276 m->count = offs;
277 break;
1da177e4 278 }
1da177e4
LT
279 }
280 m->op->stop(m, p);
4bbf439b 281 n = copy_to_iter(m->buf, m->count, iter);
1da177e4
LT
282 copied += n;
283 m->count -= n;
1f4aace6 284 m->from = n;
1da177e4 285Done:
4bbf439b
AV
286 if (unlikely(!copied)) {
287 copied = m->count ? -EFAULT : err;
288 } else {
d4d50710 289 iocb->ki_pos += copied;
8f19d472
EB
290 m->read_pos += copied;
291 }
0ac1759a 292 mutex_unlock(&m->lock);
1da177e4
LT
293 return copied;
294Enomem:
295 err = -ENOMEM;
296 goto Done;
1da177e4 297}
d4d50710 298EXPORT_SYMBOL(seq_read_iter);
1da177e4 299
1da177e4
LT
300/**
301 * seq_lseek - ->llseek() method for sequential files.
67be2dd1
MW
302 * @file: the file in question
303 * @offset: new position
254adaa4 304 * @whence: 0 for absolute, 1 for relative position
1da177e4
LT
305 *
306 * Ready-made ->f_op->llseek()
307 */
965c8e59 308loff_t seq_lseek(struct file *file, loff_t offset, int whence)
1da177e4 309{
8209e2f4 310 struct seq_file *m = file->private_data;
16abef0e 311 loff_t retval = -EINVAL;
1da177e4 312
0ac1759a 313 mutex_lock(&m->lock);
965c8e59 314 switch (whence) {
5e62adef
AM
315 case SEEK_CUR:
316 offset += file->f_pos;
df561f66 317 fallthrough;
5e62adef
AM
318 case SEEK_SET:
319 if (offset < 0)
320 break;
321 retval = offset;
322 if (offset != m->read_pos) {
323 while ((retval = traverse(m, offset)) == -EAGAIN)
324 ;
325 if (retval) {
326 /* with extreme prejudice... */
327 file->f_pos = 0;
328 m->read_pos = 0;
5e62adef
AM
329 m->index = 0;
330 m->count = 0;
331 } else {
332 m->read_pos = offset;
333 retval = file->f_pos = offset;
1da177e4 334 }
05e16745
GZ
335 } else {
336 file->f_pos = offset;
5e62adef 337 }
1da177e4 338 }
00c5746d 339 mutex_unlock(&m->lock);
1da177e4
LT
340 return retval;
341}
342EXPORT_SYMBOL(seq_lseek);
343
344/**
345 * seq_release - free the structures associated with sequential file.
346 * @file: file in question
6131ffaa 347 * @inode: its inode
1da177e4
LT
348 *
349 * Frees the structures associated with sequential file; can be used
350 * as ->f_op->release() if you don't have private data to destroy.
351 */
352int seq_release(struct inode *inode, struct file *file)
353{
8209e2f4 354 struct seq_file *m = file->private_data;
058504ed 355 kvfree(m->buf);
09652320 356 kmem_cache_free(seq_file_cache, m);
1da177e4
LT
357 return 0;
358}
359EXPORT_SYMBOL(seq_release);
360
1d31aa17
AS
361/**
362 * seq_escape_mem - print data into buffer, escaping some characters
363 * @m: target buffer
364 * @src: source buffer
365 * @len: size of source buffer
366 * @flags: flags to pass to string_escape_mem()
367 * @esc: set of characters that need escaping
368 *
369 * Puts data into buffer, replacing each occurrence of character from
370 * given class (defined by @flags and @esc) with printable escaped sequence.
371 *
372 * Use seq_has_overflowed() to check for errors.
373 */
374void seq_escape_mem(struct seq_file *m, const char *src, size_t len,
375 unsigned int flags, const char *esc)
376{
377 char *buf;
378 size_t size = seq_get_buf(m, &buf);
379 int ret;
380
381 ret = string_escape_mem(src, len, buf, size, flags, esc);
382 seq_commit(m, ret < size ? ret : -1);
383}
384EXPORT_SYMBOL(seq_escape_mem);
385
6798a8ca 386void seq_vprintf(struct seq_file *m, const char *f, va_list args)
1da177e4 387{
1da177e4
LT
388 int len;
389
390 if (m->count < m->size) {
1da177e4 391 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
1da177e4
LT
392 if (m->count + len < m->size) {
393 m->count += len;
6798a8ca 394 return;
1da177e4
LT
395 }
396 }
e075f591 397 seq_set_overflow(m);
1da177e4 398}
a4808147
SW
399EXPORT_SYMBOL(seq_vprintf);
400
6798a8ca 401void seq_printf(struct seq_file *m, const char *f, ...)
a4808147 402{
a4808147
SW
403 va_list args;
404
405 va_start(args, f);
6798a8ca 406 seq_vprintf(m, f, args);
a4808147 407 va_end(args);
a4808147 408}
1da177e4
LT
409EXPORT_SYMBOL(seq_printf);
410
76d6a133
FR
411#ifdef CONFIG_BINARY_PRINTF
412void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary)
413{
414 int len;
415
416 if (m->count < m->size) {
417 len = bstr_printf(m->buf + m->count, m->size - m->count, f,
418 binary);
419 if (m->count + len < m->size) {
420 m->count += len;
421 return;
422 }
423 }
424 seq_set_overflow(m);
425}
426EXPORT_SYMBOL(seq_bprintf);
427#endif /* CONFIG_BINARY_PRINTF */
428
74e2f334 429/**
958086d1
TE
430 * mangle_path - mangle and copy path to buffer beginning
431 * @s: buffer start
432 * @p: beginning of path in above buffer
433 * @esc: set of characters that need escaping
74e2f334
TE
434 *
435 * Copy the path from @p to @s, replacing each occurrence of character from
436 * @esc with usual octal escape.
437 * Returns pointer past last written character in @s, or NULL in case of
438 * failure.
439 */
8c9379e9 440char *mangle_path(char *s, const char *p, const char *esc)
6092d048
RP
441{
442 while (s <= p) {
443 char c = *p++;
444 if (!c) {
445 return s;
446 } else if (!strchr(esc, c)) {
447 *s++ = c;
448 } else if (s + 4 > p) {
449 break;
450 } else {
451 *s++ = '\\';
452 *s++ = '0' + ((c & 0300) >> 6);
453 *s++ = '0' + ((c & 070) >> 3);
454 *s++ = '0' + (c & 07);
455 }
456 }
457 return NULL;
458}
604094f4 459EXPORT_SYMBOL(mangle_path);
6092d048 460
52afeefb
AV
461/**
462 * seq_path - seq_file interface to print a pathname
463 * @m: the seq_file handle
464 * @path: the struct path to print
465 * @esc: set of characters to escape in the output
466 *
467 * return the absolute path of 'path', as represented by the
468 * dentry / mnt pair in the path parameter.
6092d048 469 */
8c9379e9 470int seq_path(struct seq_file *m, const struct path *path, const char *esc)
1da177e4 471{
f8439806
MS
472 char *buf;
473 size_t size = seq_get_buf(m, &buf);
474 int res = -1;
475
476 if (size) {
477 char *p = d_path(path, buf, size);
1da177e4 478 if (!IS_ERR(p)) {
f8439806
MS
479 char *end = mangle_path(buf, p, esc);
480 if (end)
481 res = end - buf;
1da177e4
LT
482 }
483 }
f8439806
MS
484 seq_commit(m, res);
485
486 return res;
1da177e4
LT
487}
488EXPORT_SYMBOL(seq_path);
489
2726d566
MS
490/**
491 * seq_file_path - seq_file interface to print a pathname of a file
492 * @m: the seq_file handle
493 * @file: the struct file to print
494 * @esc: set of characters to escape in the output
495 *
496 * return the absolute path to the file.
497 */
498int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
499{
500 return seq_path(m, &file->f_path, esc);
501}
502EXPORT_SYMBOL(seq_file_path);
503
9d1bc601
MS
504/*
505 * Same as seq_path, but relative to supplied root.
9d1bc601 506 */
8c9379e9
AV
507int seq_path_root(struct seq_file *m, const struct path *path,
508 const struct path *root, const char *esc)
9d1bc601 509{
f8439806
MS
510 char *buf;
511 size_t size = seq_get_buf(m, &buf);
512 int res = -ENAMETOOLONG;
513
514 if (size) {
9d1bc601
MS
515 char *p;
516
f8439806 517 p = __d_path(path, root, buf, size);
02125a82
AV
518 if (!p)
519 return SEQ_SKIP;
f8439806 520 res = PTR_ERR(p);
9d1bc601 521 if (!IS_ERR(p)) {
f8439806
MS
522 char *end = mangle_path(buf, p, esc);
523 if (end)
524 res = end - buf;
525 else
526 res = -ENAMETOOLONG;
9d1bc601
MS
527 }
528 }
f8439806
MS
529 seq_commit(m, res);
530
02125a82 531 return res < 0 && res != -ENAMETOOLONG ? res : 0;
9d1bc601
MS
532}
533
6092d048
RP
534/*
535 * returns the path of the 'dentry' from the root of its filesystem.
536 */
8c9379e9 537int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
6092d048 538{
f8439806
MS
539 char *buf;
540 size_t size = seq_get_buf(m, &buf);
541 int res = -1;
542
543 if (size) {
544 char *p = dentry_path(dentry, buf, size);
6092d048 545 if (!IS_ERR(p)) {
f8439806
MS
546 char *end = mangle_path(buf, p, esc);
547 if (end)
548 res = end - buf;
6092d048
RP
549 }
550 }
f8439806
MS
551 seq_commit(m, res);
552
553 return res;
6092d048 554}
c8d3fe02 555EXPORT_SYMBOL(seq_dentry);
6092d048 556
90b2433e 557void *single_start(struct seq_file *p, loff_t *pos)
1da177e4 558{
90b2433e 559 return *pos ? NULL : SEQ_START_TOKEN;
1da177e4
LT
560}
561
562static void *single_next(struct seq_file *p, void *v, loff_t *pos)
563{
564 ++*pos;
565 return NULL;
566}
567
568static void single_stop(struct seq_file *p, void *v)
569{
570}
571
572int single_open(struct file *file, int (*show)(struct seq_file *, void *),
573 void *data)
574{
d64d01a1 575 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL_ACCOUNT);
1da177e4
LT
576 int res = -ENOMEM;
577
578 if (op) {
579 op->start = single_start;
580 op->next = single_next;
581 op->stop = single_stop;
582 op->show = show;
583 res = seq_open(file, op);
584 if (!res)
585 ((struct seq_file *)file->private_data)->private = data;
586 else
587 kfree(op);
588 }
589 return res;
590}
591EXPORT_SYMBOL(single_open);
592
2043f495
AV
593int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
594 void *data, size_t size)
595{
058504ed 596 char *buf = seq_buf_alloc(size);
2043f495
AV
597 int ret;
598 if (!buf)
599 return -ENOMEM;
600 ret = single_open(file, show, data);
601 if (ret) {
058504ed 602 kvfree(buf);
2043f495
AV
603 return ret;
604 }
605 ((struct seq_file *)file->private_data)->buf = buf;
606 ((struct seq_file *)file->private_data)->size = size;
607 return 0;
608}
609EXPORT_SYMBOL(single_open_size);
610
1da177e4
LT
611int single_release(struct inode *inode, struct file *file)
612{
15ad7cdc 613 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
1da177e4
LT
614 int res = seq_release(inode, file);
615 kfree(op);
616 return res;
617}
618EXPORT_SYMBOL(single_release);
619
620int seq_release_private(struct inode *inode, struct file *file)
621{
622 struct seq_file *seq = file->private_data;
623
624 kfree(seq->private);
625 seq->private = NULL;
626 return seq_release(inode, file);
627}
628EXPORT_SYMBOL(seq_release_private);
629
39699037
PE
630void *__seq_open_private(struct file *f, const struct seq_operations *ops,
631 int psize)
632{
633 int rc;
634 void *private;
635 struct seq_file *seq;
636
d64d01a1 637 private = kzalloc(psize, GFP_KERNEL_ACCOUNT);
39699037
PE
638 if (private == NULL)
639 goto out;
640
641 rc = seq_open(f, ops);
642 if (rc < 0)
643 goto out_free;
644
645 seq = f->private_data;
646 seq->private = private;
647 return private;
648
649out_free:
650 kfree(private);
651out:
652 return NULL;
653}
654EXPORT_SYMBOL(__seq_open_private);
655
656int seq_open_private(struct file *filp, const struct seq_operations *ops,
657 int psize)
658{
659 return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
660}
661EXPORT_SYMBOL(seq_open_private);
662
6798a8ca 663void seq_putc(struct seq_file *m, char c)
1da177e4 664{
6798a8ca
JP
665 if (m->count >= m->size)
666 return;
667
668 m->buf[m->count++] = c;
1da177e4
LT
669}
670EXPORT_SYMBOL(seq_putc);
671
6798a8ca 672void seq_puts(struct seq_file *m, const char *s)
1da177e4
LT
673{
674 int len = strlen(s);
6798a8ca
JP
675
676 if (m->count + len >= m->size) {
677 seq_set_overflow(m);
678 return;
1da177e4 679 }
6798a8ca
JP
680 memcpy(m->buf + m->count, s, len);
681 m->count += len;
1da177e4
LT
682}
683EXPORT_SYMBOL(seq_puts);
bcf67e16 684
d1be35cb 685/**
961f3c89
MCC
686 * seq_put_decimal_ull_width - A helper routine for putting decimal numbers
687 * without rich format of printf().
1ac101a5 688 * only 'unsigned long long' is supported.
d1be35cb
AV
689 * @m: seq_file identifying the buffer to which data should be written
690 * @delimiter: a string which is printed before the number
691 * @num: the number
692 * @width: a minimum field width
693 *
694 * This routine will put strlen(delimiter) + number into seq_filed.
1ac101a5
KH
695 * This routine is very quick when you show lots of numbers.
696 * In usual cases, it will be better to use seq_printf(). It's easier to read.
697 */
d1be35cb
AV
698void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
699 unsigned long long num, unsigned int width)
1ac101a5
KH
700{
701 int len;
702
703 if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */
704 goto overflow;
705
48dffbf8
AV
706 if (delimiter && delimiter[0]) {
707 if (delimiter[1] == 0)
708 seq_putc(m, delimiter[0]);
709 else
710 seq_puts(m, delimiter);
711 }
75ba1d07 712
d1be35cb
AV
713 if (!width)
714 width = 1;
715
716 if (m->count + width >= m->size)
75ba1d07 717 goto overflow;
1ac101a5 718
d1be35cb 719 len = num_to_str(m->buf + m->count, m->size - m->count, num, width);
1ac101a5
KH
720 if (!len)
721 goto overflow;
75ba1d07 722
1ac101a5 723 m->count += len;
6798a8ca
JP
724 return;
725
1ac101a5 726overflow:
e075f591 727 seq_set_overflow(m);
1ac101a5 728}
d1be35cb
AV
729
730void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
731 unsigned long long num)
732{
733 return seq_put_decimal_ull_width(m, delimiter, num, 0);
734}
1ac101a5
KH
735EXPORT_SYMBOL(seq_put_decimal_ull);
736
0e3dc019
AV
737/**
738 * seq_put_hex_ll - put a number in hexadecimal notation
739 * @m: seq_file identifying the buffer to which data should be written
740 * @delimiter: a string which is printed before the number
741 * @v: the number
742 * @width: a minimum field width
743 *
744 * seq_put_hex_ll(m, "", v, 8) is equal to seq_printf(m, "%08llx", v)
745 *
746 * This routine is very quick when you show lots of numbers.
747 * In usual cases, it will be better to use seq_printf(). It's easier to read.
748 */
749void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
750 unsigned long long v, unsigned int width)
751{
752 unsigned int len;
753 int i;
754
755 if (delimiter && delimiter[0]) {
756 if (delimiter[1] == 0)
757 seq_putc(m, delimiter[0]);
758 else
759 seq_puts(m, delimiter);
760 }
761
762 /* If x is 0, the result of __builtin_clzll is undefined */
763 if (v == 0)
764 len = 1;
765 else
766 len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4;
767
768 if (len < width)
769 len = width;
770
771 if (m->count + len > m->size) {
772 seq_set_overflow(m);
773 return;
774 }
775
776 for (i = len - 1; i >= 0; i--) {
777 m->buf[m->count + i] = hex_asc[0xf & v];
778 v = v >> 4;
779 }
780 m->count += len;
781}
782
75ba1d07 783void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num)
bda7bad6 784{
75ba1d07
JP
785 int len;
786
787 if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */
788 goto overflow;
789
48dffbf8
AV
790 if (delimiter && delimiter[0]) {
791 if (delimiter[1] == 0)
792 seq_putc(m, delimiter[0]);
793 else
794 seq_puts(m, delimiter);
795 }
75ba1d07
JP
796
797 if (m->count + 2 >= m->size)
798 goto overflow;
799
bda7bad6 800 if (num < 0) {
75ba1d07 801 m->buf[m->count++] = '-';
bda7bad6 802 num = -num;
bda7bad6 803 }
75ba1d07
JP
804
805 if (num < 10) {
806 m->buf[m->count++] = num + '0';
807 return;
808 }
809
d1be35cb 810 len = num_to_str(m->buf + m->count, m->size - m->count, num, 0);
75ba1d07
JP
811 if (!len)
812 goto overflow;
813
814 m->count += len;
815 return;
816
817overflow:
818 seq_set_overflow(m);
bda7bad6
KH
819}
820EXPORT_SYMBOL(seq_put_decimal_ll);
821
0b923606
PO
822/**
823 * seq_write - write arbitrary data to buffer
824 * @seq: seq_file identifying the buffer to which data should be written
825 * @data: data address
826 * @len: number of bytes
827 *
828 * Return 0 on success, non-zero otherwise.
829 */
830int seq_write(struct seq_file *seq, const void *data, size_t len)
831{
832 if (seq->count + len < seq->size) {
833 memcpy(seq->buf + seq->count, data, len);
834 seq->count += len;
835 return 0;
836 }
e075f591 837 seq_set_overflow(seq);
0b923606
PO
838 return -1;
839}
840EXPORT_SYMBOL(seq_write);
841
839cc2a9
TH
842/**
843 * seq_pad - write padding spaces to buffer
844 * @m: seq_file identifying the buffer to which data should be written
845 * @c: the byte to append after padding if non-zero
846 */
847void seq_pad(struct seq_file *m, char c)
848{
849 int size = m->pad_until - m->count;
8cfa67b4
AV
850 if (size > 0) {
851 if (size + m->count > m->size) {
852 seq_set_overflow(m);
853 return;
854 }
855 memset(m->buf + m->count, ' ', size);
856 m->count += size;
857 }
839cc2a9
TH
858 if (c)
859 seq_putc(m, c);
860}
861EXPORT_SYMBOL(seq_pad);
862
37607102
AS
863/* A complete analogue of print_hex_dump() */
864void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
865 int rowsize, int groupsize, const void *buf, size_t len,
866 bool ascii)
867{
868 const u8 *ptr = buf;
869 int i, linelen, remaining = len;
8b91a318
AS
870 char *buffer;
871 size_t size;
37607102
AS
872 int ret;
873
874 if (rowsize != 16 && rowsize != 32)
875 rowsize = 16;
876
877 for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
878 linelen = min(remaining, rowsize);
879 remaining -= rowsize;
880
881 switch (prefix_type) {
882 case DUMP_PREFIX_ADDRESS:
883 seq_printf(m, "%s%p: ", prefix_str, ptr + i);
884 break;
885 case DUMP_PREFIX_OFFSET:
886 seq_printf(m, "%s%.8x: ", prefix_str, i);
887 break;
888 default:
889 seq_printf(m, "%s", prefix_str);
890 break;
891 }
892
8b91a318 893 size = seq_get_buf(m, &buffer);
37607102 894 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
8b91a318
AS
895 buffer, size, ascii);
896 seq_commit(m, ret < size ? ret : -1);
897
898 seq_putc(m, '\n');
37607102
AS
899 }
900}
901EXPORT_SYMBOL(seq_hex_dump);
902
bcf67e16
PE
903struct list_head *seq_list_start(struct list_head *head, loff_t pos)
904{
905 struct list_head *lh;
906
907 list_for_each(lh, head)
908 if (pos-- == 0)
909 return lh;
910
911 return NULL;
912}
bcf67e16
PE
913EXPORT_SYMBOL(seq_list_start);
914
915struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
916{
917 if (!pos)
918 return head;
919
920 return seq_list_start(head, pos - 1);
921}
bcf67e16
PE
922EXPORT_SYMBOL(seq_list_start_head);
923
924struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
925{
926 struct list_head *lh;
927
928 lh = ((struct list_head *)v)->next;
929 ++*ppos;
930 return lh == head ? NULL : lh;
931}
bcf67e16 932EXPORT_SYMBOL(seq_list_next);
66655de6 933
ad25f5cb
DH
934struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos)
935{
936 struct list_head *lh;
937
938 list_for_each_rcu(lh, head)
939 if (pos-- == 0)
940 return lh;
941
942 return NULL;
943}
944EXPORT_SYMBOL(seq_list_start_rcu);
945
946struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos)
947{
948 if (!pos)
949 return head;
950
951 return seq_list_start_rcu(head, pos - 1);
952}
953EXPORT_SYMBOL(seq_list_start_head_rcu);
954
955struct list_head *seq_list_next_rcu(void *v, struct list_head *head,
956 loff_t *ppos)
957{
958 struct list_head *lh;
959
960 lh = list_next_rcu((struct list_head *)v);
961 ++*ppos;
962 return lh == head ? NULL : lh;
963}
964EXPORT_SYMBOL(seq_list_next_rcu);
965
66655de6
LZ
966/**
967 * seq_hlist_start - start an iteration of a hlist
968 * @head: the head of the hlist
969 * @pos: the start position of the sequence
970 *
971 * Called at seq_file->op->start().
972 */
973struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
974{
975 struct hlist_node *node;
976
977 hlist_for_each(node, head)
978 if (pos-- == 0)
979 return node;
980 return NULL;
981}
982EXPORT_SYMBOL(seq_hlist_start);
983
984/**
985 * seq_hlist_start_head - start an iteration of a hlist
986 * @head: the head of the hlist
987 * @pos: the start position of the sequence
988 *
989 * Called at seq_file->op->start(). Call this function if you want to
990 * print a header at the top of the output.
991 */
992struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
993{
994 if (!pos)
995 return SEQ_START_TOKEN;
996
997 return seq_hlist_start(head, pos - 1);
998}
999EXPORT_SYMBOL(seq_hlist_start_head);
1000
1001/**
1002 * seq_hlist_next - move to the next position of the hlist
1003 * @v: the current iterator
1004 * @head: the head of the hlist
138860b9 1005 * @ppos: the current position
66655de6
LZ
1006 *
1007 * Called at seq_file->op->next().
1008 */
1009struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
1010 loff_t *ppos)
1011{
1012 struct hlist_node *node = v;
1013
1014 ++*ppos;
1015 if (v == SEQ_START_TOKEN)
1016 return head->first;
1017 else
1018 return node->next;
1019}
1020EXPORT_SYMBOL(seq_hlist_next);
1cc52327 1021
1022/**
1023 * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
1024 * @head: the head of the hlist
1025 * @pos: the start position of the sequence
1026 *
1027 * Called at seq_file->op->start().
1028 *
1029 * This list-traversal primitive may safely run concurrently with
1030 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1031 * as long as the traversal is guarded by rcu_read_lock().
1032 */
1033struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
1034 loff_t pos)
1035{
1036 struct hlist_node *node;
1037
1038 __hlist_for_each_rcu(node, head)
1039 if (pos-- == 0)
1040 return node;
1041 return NULL;
1042}
1043EXPORT_SYMBOL(seq_hlist_start_rcu);
1044
1045/**
1046 * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
1047 * @head: the head of the hlist
1048 * @pos: the start position of the sequence
1049 *
1050 * Called at seq_file->op->start(). Call this function if you want to
1051 * print a header at the top of the output.
1052 *
1053 * This list-traversal primitive may safely run concurrently with
1054 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1055 * as long as the traversal is guarded by rcu_read_lock().
1056 */
1057struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
1058 loff_t pos)
1059{
1060 if (!pos)
1061 return SEQ_START_TOKEN;
1062
1063 return seq_hlist_start_rcu(head, pos - 1);
1064}
1065EXPORT_SYMBOL(seq_hlist_start_head_rcu);
1066
1067/**
1068 * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
1069 * @v: the current iterator
1070 * @head: the head of the hlist
138860b9 1071 * @ppos: the current position
1cc52327 1072 *
1073 * Called at seq_file->op->next().
1074 *
1075 * This list-traversal primitive may safely run concurrently with
1076 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1077 * as long as the traversal is guarded by rcu_read_lock().
1078 */
1079struct hlist_node *seq_hlist_next_rcu(void *v,
1080 struct hlist_head *head,
1081 loff_t *ppos)
1082{
1083 struct hlist_node *node = v;
1084
1085 ++*ppos;
1086 if (v == SEQ_START_TOKEN)
1087 return rcu_dereference(head->first);
1088 else
1089 return rcu_dereference(node->next);
1090}
1091EXPORT_SYMBOL(seq_hlist_next_rcu);
0bc77381
JL
1092
1093/**
961f3c89 1094 * seq_hlist_start_percpu - start an iteration of a percpu hlist array
0bc77381
JL
1095 * @head: pointer to percpu array of struct hlist_heads
1096 * @cpu: pointer to cpu "cursor"
1097 * @pos: start position of sequence
1098 *
1099 * Called at seq_file->op->start().
1100 */
1101struct hlist_node *
1102seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
1103{
1104 struct hlist_node *node;
1105
1106 for_each_possible_cpu(*cpu) {
1107 hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
1108 if (pos-- == 0)
1109 return node;
1110 }
1111 }
1112 return NULL;
1113}
1114EXPORT_SYMBOL(seq_hlist_start_percpu);
1115
1116/**
1117 * seq_hlist_next_percpu - move to the next position of the percpu hlist array
1118 * @v: pointer to current hlist_node
1119 * @head: pointer to percpu array of struct hlist_heads
1120 * @cpu: pointer to cpu "cursor"
1121 * @pos: start position of sequence
1122 *
1123 * Called at seq_file->op->next().
1124 */
1125struct hlist_node *
1126seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
1127 int *cpu, loff_t *pos)
1128{
1129 struct hlist_node *node = v;
1130
1131 ++*pos;
1132
1133 if (node->next)
1134 return node->next;
1135
1136 for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
1137 *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
1138 struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
1139
1140 if (!hlist_empty(bucket))
1141 return bucket->first;
1142 }
1143 return NULL;
1144}
1145EXPORT_SYMBOL(seq_hlist_next_percpu);
09652320
AD
1146
1147void __init seq_file_init(void)
1148{
d64d01a1 1149 seq_file_cache = KMEM_CACHE(seq_file, SLAB_ACCOUNT|SLAB_PANIC);
09652320 1150}