1 // SPDX-License-Identifier: GPL-2.0
5 * helper functions for making synthetic files from sequences of records.
6 * initial implementation -- AV, Oct 2001.
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 #include <linux/cache.h>
13 #include <linux/export.h>
14 #include <linux/seq_file.h>
15 #include <linux/vmalloc.h>
16 #include <linux/slab.h>
17 #include <linux/cred.h>
19 #include <linux/printk.h>
20 #include <linux/string_helpers.h>
21 #include <linux/uio.h>
23 #include <linux/uaccess.h>
26 static struct kmem_cache *seq_file_cache __ro_after_init;
28 static void seq_set_overflow(struct seq_file *m)
33 static void *seq_buf_alloc(unsigned long size)
35 return kvmalloc(size, GFP_KERNEL_ACCOUNT);
39 * seq_open - initialize sequential file
40 * @file: file we initialize
41 * @op: method table describing the sequence
43 * seq_open() sets @file, associating it with a sequence described
44 * by @op. @op->start() sets the iterator up and returns the first
45 * element of sequence. @op->stop() shuts it down. @op->next()
46 * returns the next element of sequence. @op->show() prints element
47 * into the buffer. In case of error ->start() and ->next() return
48 * ERR_PTR(error). In the end of sequence they return %NULL. ->show()
49 * returns 0 in case of success and negative number in case of error.
50 * Returning SEQ_SKIP means "discard this element and move on".
51 * Note: seq_open() will allocate a struct seq_file and store its
52 * pointer in @file->private_data. This pointer should not be modified.
54 int seq_open(struct file *file, const struct seq_operations *op)
58 WARN_ON(file->private_data);
60 p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL);
64 file->private_data = p;
69 // No refcounting: the lifetime of 'p' is constrained
70 // to the lifetime of the file.
74 * seq_files support lseek() and pread(). They do not implement
75 * write() at all, but we clear FMODE_PWRITE here for historical
78 * If a client of seq_files a) implements file.write() and b) wishes to
79 * support pwrite() then that client will need to implement its own
80 * file.open() which calls seq_open() and then sets FMODE_PWRITE.
82 file->f_mode &= ~FMODE_PWRITE;
85 EXPORT_SYMBOL(seq_open);
87 static int traverse(struct seq_file *m, loff_t offset)
94 m->count = m->from = 0;
99 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
103 p = m->op->start(m, &m->index);
108 error = m->op->show(m, p);
111 if (unlikely(error)) {
115 if (seq_has_overflowed(m))
117 p = m->op->next(m, p, &m->index);
118 if (pos + m->count > offset) {
119 m->from = offset - pos;
135 m->buf = seq_buf_alloc(m->size <<= 1);
136 return !m->buf ? -ENOMEM : -EAGAIN;
140 * seq_read - ->read() method for sequential files.
141 * @file: the file to read from
142 * @buf: the buffer to read to
143 * @size: the maximum number of bytes to read
144 * @ppos: the current position in the file
146 * Ready-made ->f_op->read()
148 ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
150 struct iovec iov = { .iov_base = buf, .iov_len = size};
152 struct iov_iter iter;
155 init_sync_kiocb(&kiocb, file);
156 iov_iter_init(&iter, READ, &iov, 1, size);
158 kiocb.ki_pos = *ppos;
159 ret = seq_read_iter(&kiocb, &iter);
160 *ppos = kiocb.ki_pos;
163 EXPORT_SYMBOL(seq_read);
166 * Ready-made ->f_op->read_iter()
168 ssize_t seq_read_iter(struct kiocb *iocb, struct iov_iter *iter)
170 struct seq_file *m = iocb->ki_filp->private_data;
176 if (!iov_iter_count(iter))
179 mutex_lock(&m->lock);
182 * if request is to read from zero offset, reset iterator to first
183 * record as it might have been already advanced by previous requests
185 if (iocb->ki_pos == 0) {
190 /* Don't assume ki_pos is where we left it */
191 if (unlikely(iocb->ki_pos != m->read_pos)) {
192 while ((err = traverse(m, iocb->ki_pos)) == -EAGAIN)
195 /* With prejudice... */
201 m->read_pos = iocb->ki_pos;
205 /* grab buffer if we didn't have one */
207 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
211 // something left in the buffer - copy it out first
213 n = copy_to_iter(m->buf + m->from, m->count, iter);
217 if (m->count) // hadn't managed to copy everything
220 // get a non-empty record in the buffer
222 p = m->op->start(m, &m->index);
225 if (!p || IS_ERR(p)) // EOF or an error
227 err = m->op->show(m, p);
228 if (err < 0) // hard error
230 if (unlikely(err)) // ->show() says "skip it"
232 if (unlikely(!m->count)) { // empty record
233 p = m->op->next(m, p, &m->index);
236 if (!seq_has_overflowed(m)) // got it
238 // need a bigger buffer
242 m->buf = seq_buf_alloc(m->size <<= 1);
245 p = m->op->start(m, &m->index);
252 // one non-empty record is in the buffer; if they want more,
253 // try to fit more in, but in any case we need to advance
254 // the iterator once for every record shown.
256 size_t offs = m->count;
257 loff_t pos = m->index;
259 p = m->op->next(m, p, &m->index);
260 if (pos == m->index) {
261 pr_info_ratelimited("buggy .next function %ps did not update position index\n",
265 if (!p || IS_ERR(p)) // no next record for us
267 if (m->count >= iov_iter_count(iter))
269 err = m->op->show(m, p);
270 if (err > 0) { // ->show() says "skip it"
272 } else if (err || seq_has_overflowed(m)) {
278 n = copy_to_iter(m->buf, m->count, iter);
283 if (unlikely(!copied)) {
284 copied = m->count ? -EFAULT : err;
286 iocb->ki_pos += copied;
287 m->read_pos += copied;
289 mutex_unlock(&m->lock);
295 EXPORT_SYMBOL(seq_read_iter);
298 * seq_lseek - ->llseek() method for sequential files.
299 * @file: the file in question
300 * @offset: new position
301 * @whence: 0 for absolute, 1 for relative position
303 * Ready-made ->f_op->llseek()
305 loff_t seq_lseek(struct file *file, loff_t offset, int whence)
307 struct seq_file *m = file->private_data;
308 loff_t retval = -EINVAL;
310 mutex_lock(&m->lock);
313 offset += file->f_pos;
319 if (offset != m->read_pos) {
320 while ((retval = traverse(m, offset)) == -EAGAIN)
323 /* with extreme prejudice... */
329 m->read_pos = offset;
330 retval = file->f_pos = offset;
333 file->f_pos = offset;
336 mutex_unlock(&m->lock);
339 EXPORT_SYMBOL(seq_lseek);
342 * seq_release - free the structures associated with sequential file.
343 * @file: file in question
346 * Frees the structures associated with sequential file; can be used
347 * as ->f_op->release() if you don't have private data to destroy.
349 int seq_release(struct inode *inode, struct file *file)
351 struct seq_file *m = file->private_data;
353 kmem_cache_free(seq_file_cache, m);
356 EXPORT_SYMBOL(seq_release);
359 * seq_escape_mem - print data into buffer, escaping some characters
361 * @src: source buffer
362 * @len: size of source buffer
363 * @flags: flags to pass to string_escape_mem()
364 * @esc: set of characters that need escaping
366 * Puts data into buffer, replacing each occurrence of character from
367 * given class (defined by @flags and @esc) with printable escaped sequence.
369 * Use seq_has_overflowed() to check for errors.
371 void seq_escape_mem(struct seq_file *m, const char *src, size_t len,
372 unsigned int flags, const char *esc)
375 size_t size = seq_get_buf(m, &buf);
378 ret = string_escape_mem(src, len, buf, size, flags, esc);
379 seq_commit(m, ret < size ? ret : -1);
381 EXPORT_SYMBOL(seq_escape_mem);
384 * seq_escape - print string into buffer, escaping some characters
387 * @esc: set of characters that need escaping
389 * Puts string into buffer, replacing each occurrence of character from
390 * @esc with usual octal escape.
391 * Use seq_has_overflowed() to check for errors.
393 void seq_escape(struct seq_file *m, const char *s, const char *esc)
395 seq_escape_str(m, s, ESCAPE_OCTAL, esc);
397 EXPORT_SYMBOL(seq_escape);
399 void seq_escape_mem_ascii(struct seq_file *m, const char *src, size_t isz)
402 size_t size = seq_get_buf(m, &buf);
405 ret = string_escape_mem_ascii(src, isz, buf, size);
406 seq_commit(m, ret < size ? ret : -1);
408 EXPORT_SYMBOL(seq_escape_mem_ascii);
410 void seq_vprintf(struct seq_file *m, const char *f, va_list args)
414 if (m->count < m->size) {
415 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
416 if (m->count + len < m->size) {
423 EXPORT_SYMBOL(seq_vprintf);
425 void seq_printf(struct seq_file *m, const char *f, ...)
430 seq_vprintf(m, f, args);
433 EXPORT_SYMBOL(seq_printf);
435 #ifdef CONFIG_BINARY_PRINTF
436 void seq_bprintf(struct seq_file *m, const char *f, const u32 *binary)
440 if (m->count < m->size) {
441 len = bstr_printf(m->buf + m->count, m->size - m->count, f,
443 if (m->count + len < m->size) {
450 EXPORT_SYMBOL(seq_bprintf);
451 #endif /* CONFIG_BINARY_PRINTF */
454 * mangle_path - mangle and copy path to buffer beginning
456 * @p: beginning of path in above buffer
457 * @esc: set of characters that need escaping
459 * Copy the path from @p to @s, replacing each occurrence of character from
460 * @esc with usual octal escape.
461 * Returns pointer past last written character in @s, or NULL in case of
464 char *mangle_path(char *s, const char *p, const char *esc)
470 } else if (!strchr(esc, c)) {
472 } else if (s + 4 > p) {
476 *s++ = '0' + ((c & 0300) >> 6);
477 *s++ = '0' + ((c & 070) >> 3);
478 *s++ = '0' + (c & 07);
483 EXPORT_SYMBOL(mangle_path);
486 * seq_path - seq_file interface to print a pathname
487 * @m: the seq_file handle
488 * @path: the struct path to print
489 * @esc: set of characters to escape in the output
491 * return the absolute path of 'path', as represented by the
492 * dentry / mnt pair in the path parameter.
494 int seq_path(struct seq_file *m, const struct path *path, const char *esc)
497 size_t size = seq_get_buf(m, &buf);
501 char *p = d_path(path, buf, size);
503 char *end = mangle_path(buf, p, esc);
512 EXPORT_SYMBOL(seq_path);
515 * seq_file_path - seq_file interface to print a pathname of a file
516 * @m: the seq_file handle
517 * @file: the struct file to print
518 * @esc: set of characters to escape in the output
520 * return the absolute path to the file.
522 int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
524 return seq_path(m, &file->f_path, esc);
526 EXPORT_SYMBOL(seq_file_path);
529 * Same as seq_path, but relative to supplied root.
531 int seq_path_root(struct seq_file *m, const struct path *path,
532 const struct path *root, const char *esc)
535 size_t size = seq_get_buf(m, &buf);
536 int res = -ENAMETOOLONG;
541 p = __d_path(path, root, buf, size);
546 char *end = mangle_path(buf, p, esc);
555 return res < 0 && res != -ENAMETOOLONG ? res : 0;
559 * returns the path of the 'dentry' from the root of its filesystem.
561 int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
564 size_t size = seq_get_buf(m, &buf);
568 char *p = dentry_path(dentry, buf, size);
570 char *end = mangle_path(buf, p, esc);
579 EXPORT_SYMBOL(seq_dentry);
581 static void *single_start(struct seq_file *p, loff_t *pos)
583 return NULL + (*pos == 0);
586 static void *single_next(struct seq_file *p, void *v, loff_t *pos)
592 static void single_stop(struct seq_file *p, void *v)
596 int single_open(struct file *file, int (*show)(struct seq_file *, void *),
599 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL_ACCOUNT);
603 op->start = single_start;
604 op->next = single_next;
605 op->stop = single_stop;
607 res = seq_open(file, op);
609 ((struct seq_file *)file->private_data)->private = data;
615 EXPORT_SYMBOL(single_open);
617 int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
618 void *data, size_t size)
620 char *buf = seq_buf_alloc(size);
624 ret = single_open(file, show, data);
629 ((struct seq_file *)file->private_data)->buf = buf;
630 ((struct seq_file *)file->private_data)->size = size;
633 EXPORT_SYMBOL(single_open_size);
635 int single_release(struct inode *inode, struct file *file)
637 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
638 int res = seq_release(inode, file);
642 EXPORT_SYMBOL(single_release);
644 int seq_release_private(struct inode *inode, struct file *file)
646 struct seq_file *seq = file->private_data;
650 return seq_release(inode, file);
652 EXPORT_SYMBOL(seq_release_private);
654 void *__seq_open_private(struct file *f, const struct seq_operations *ops,
659 struct seq_file *seq;
661 private = kzalloc(psize, GFP_KERNEL_ACCOUNT);
665 rc = seq_open(f, ops);
669 seq = f->private_data;
670 seq->private = private;
678 EXPORT_SYMBOL(__seq_open_private);
680 int seq_open_private(struct file *filp, const struct seq_operations *ops,
683 return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
685 EXPORT_SYMBOL(seq_open_private);
687 void seq_putc(struct seq_file *m, char c)
689 if (m->count >= m->size)
692 m->buf[m->count++] = c;
694 EXPORT_SYMBOL(seq_putc);
696 void seq_puts(struct seq_file *m, const char *s)
700 if (m->count + len >= m->size) {
704 memcpy(m->buf + m->count, s, len);
707 EXPORT_SYMBOL(seq_puts);
710 * seq_put_decimal_ull_width - A helper routine for putting decimal numbers
711 * without rich format of printf().
712 * only 'unsigned long long' is supported.
713 * @m: seq_file identifying the buffer to which data should be written
714 * @delimiter: a string which is printed before the number
716 * @width: a minimum field width
718 * This routine will put strlen(delimiter) + number into seq_filed.
719 * This routine is very quick when you show lots of numbers.
720 * In usual cases, it will be better to use seq_printf(). It's easier to read.
722 void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
723 unsigned long long num, unsigned int width)
727 if (m->count + 2 >= m->size) /* we'll write 2 bytes at least */
730 if (delimiter && delimiter[0]) {
731 if (delimiter[1] == 0)
732 seq_putc(m, delimiter[0]);
734 seq_puts(m, delimiter);
740 if (m->count + width >= m->size)
743 len = num_to_str(m->buf + m->count, m->size - m->count, num, width);
754 void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
755 unsigned long long num)
757 return seq_put_decimal_ull_width(m, delimiter, num, 0);
759 EXPORT_SYMBOL(seq_put_decimal_ull);
762 * seq_put_hex_ll - put a number in hexadecimal notation
763 * @m: seq_file identifying the buffer to which data should be written
764 * @delimiter: a string which is printed before the number
766 * @width: a minimum field width
768 * seq_put_hex_ll(m, "", v, 8) is equal to seq_printf(m, "%08llx", v)
770 * This routine is very quick when you show lots of numbers.
771 * In usual cases, it will be better to use seq_printf(). It's easier to read.
773 void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
774 unsigned long long v, unsigned int width)
779 if (delimiter && delimiter[0]) {
780 if (delimiter[1] == 0)
781 seq_putc(m, delimiter[0]);
783 seq_puts(m, delimiter);
786 /* If x is 0, the result of __builtin_clzll is undefined */
790 len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4;
795 if (m->count + len > m->size) {
800 for (i = len - 1; i >= 0; i--) {
801 m->buf[m->count + i] = hex_asc[0xf & v];
807 void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num)
811 if (m->count + 3 >= m->size) /* we'll write 2 bytes at least */
814 if (delimiter && delimiter[0]) {
815 if (delimiter[1] == 0)
816 seq_putc(m, delimiter[0]);
818 seq_puts(m, delimiter);
821 if (m->count + 2 >= m->size)
825 m->buf[m->count++] = '-';
830 m->buf[m->count++] = num + '0';
834 len = num_to_str(m->buf + m->count, m->size - m->count, num, 0);
844 EXPORT_SYMBOL(seq_put_decimal_ll);
847 * seq_write - write arbitrary data to buffer
848 * @seq: seq_file identifying the buffer to which data should be written
849 * @data: data address
850 * @len: number of bytes
852 * Return 0 on success, non-zero otherwise.
854 int seq_write(struct seq_file *seq, const void *data, size_t len)
856 if (seq->count + len < seq->size) {
857 memcpy(seq->buf + seq->count, data, len);
861 seq_set_overflow(seq);
864 EXPORT_SYMBOL(seq_write);
867 * seq_pad - write padding spaces to buffer
868 * @m: seq_file identifying the buffer to which data should be written
869 * @c: the byte to append after padding if non-zero
871 void seq_pad(struct seq_file *m, char c)
873 int size = m->pad_until - m->count;
875 if (size + m->count > m->size) {
879 memset(m->buf + m->count, ' ', size);
885 EXPORT_SYMBOL(seq_pad);
887 /* A complete analogue of print_hex_dump() */
888 void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
889 int rowsize, int groupsize, const void *buf, size_t len,
893 int i, linelen, remaining = len;
898 if (rowsize != 16 && rowsize != 32)
901 for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
902 linelen = min(remaining, rowsize);
903 remaining -= rowsize;
905 switch (prefix_type) {
906 case DUMP_PREFIX_ADDRESS:
907 seq_printf(m, "%s%p: ", prefix_str, ptr + i);
909 case DUMP_PREFIX_OFFSET:
910 seq_printf(m, "%s%.8x: ", prefix_str, i);
913 seq_printf(m, "%s", prefix_str);
917 size = seq_get_buf(m, &buffer);
918 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
919 buffer, size, ascii);
920 seq_commit(m, ret < size ? ret : -1);
925 EXPORT_SYMBOL(seq_hex_dump);
927 struct list_head *seq_list_start(struct list_head *head, loff_t pos)
929 struct list_head *lh;
931 list_for_each(lh, head)
937 EXPORT_SYMBOL(seq_list_start);
939 struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
944 return seq_list_start(head, pos - 1);
946 EXPORT_SYMBOL(seq_list_start_head);
948 struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
950 struct list_head *lh;
952 lh = ((struct list_head *)v)->next;
954 return lh == head ? NULL : lh;
956 EXPORT_SYMBOL(seq_list_next);
959 * seq_hlist_start - start an iteration of a hlist
960 * @head: the head of the hlist
961 * @pos: the start position of the sequence
963 * Called at seq_file->op->start().
965 struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
967 struct hlist_node *node;
969 hlist_for_each(node, head)
974 EXPORT_SYMBOL(seq_hlist_start);
977 * seq_hlist_start_head - start an iteration of a hlist
978 * @head: the head of the hlist
979 * @pos: the start position of the sequence
981 * Called at seq_file->op->start(). Call this function if you want to
982 * print a header at the top of the output.
984 struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
987 return SEQ_START_TOKEN;
989 return seq_hlist_start(head, pos - 1);
991 EXPORT_SYMBOL(seq_hlist_start_head);
994 * seq_hlist_next - move to the next position of the hlist
995 * @v: the current iterator
996 * @head: the head of the hlist
997 * @ppos: the current position
999 * Called at seq_file->op->next().
1001 struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
1004 struct hlist_node *node = v;
1007 if (v == SEQ_START_TOKEN)
1012 EXPORT_SYMBOL(seq_hlist_next);
1015 * seq_hlist_start_rcu - start an iteration of a hlist protected by RCU
1016 * @head: the head of the hlist
1017 * @pos: the start position of the sequence
1019 * Called at seq_file->op->start().
1021 * This list-traversal primitive may safely run concurrently with
1022 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1023 * as long as the traversal is guarded by rcu_read_lock().
1025 struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
1028 struct hlist_node *node;
1030 __hlist_for_each_rcu(node, head)
1035 EXPORT_SYMBOL(seq_hlist_start_rcu);
1038 * seq_hlist_start_head_rcu - start an iteration of a hlist protected by RCU
1039 * @head: the head of the hlist
1040 * @pos: the start position of the sequence
1042 * Called at seq_file->op->start(). Call this function if you want to
1043 * print a header at the top of the output.
1045 * This list-traversal primitive may safely run concurrently with
1046 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1047 * as long as the traversal is guarded by rcu_read_lock().
1049 struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
1053 return SEQ_START_TOKEN;
1055 return seq_hlist_start_rcu(head, pos - 1);
1057 EXPORT_SYMBOL(seq_hlist_start_head_rcu);
1060 * seq_hlist_next_rcu - move to the next position of the hlist protected by RCU
1061 * @v: the current iterator
1062 * @head: the head of the hlist
1063 * @ppos: the current position
1065 * Called at seq_file->op->next().
1067 * This list-traversal primitive may safely run concurrently with
1068 * the _rcu list-mutation primitives such as hlist_add_head_rcu()
1069 * as long as the traversal is guarded by rcu_read_lock().
1071 struct hlist_node *seq_hlist_next_rcu(void *v,
1072 struct hlist_head *head,
1075 struct hlist_node *node = v;
1078 if (v == SEQ_START_TOKEN)
1079 return rcu_dereference(head->first);
1081 return rcu_dereference(node->next);
1083 EXPORT_SYMBOL(seq_hlist_next_rcu);
1086 * seq_hlist_start_percpu - start an iteration of a percpu hlist array
1087 * @head: pointer to percpu array of struct hlist_heads
1088 * @cpu: pointer to cpu "cursor"
1089 * @pos: start position of sequence
1091 * Called at seq_file->op->start().
1094 seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
1096 struct hlist_node *node;
1098 for_each_possible_cpu(*cpu) {
1099 hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
1106 EXPORT_SYMBOL(seq_hlist_start_percpu);
1109 * seq_hlist_next_percpu - move to the next position of the percpu hlist array
1110 * @v: pointer to current hlist_node
1111 * @head: pointer to percpu array of struct hlist_heads
1112 * @cpu: pointer to cpu "cursor"
1113 * @pos: start position of sequence
1115 * Called at seq_file->op->next().
1118 seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
1119 int *cpu, loff_t *pos)
1121 struct hlist_node *node = v;
1128 for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
1129 *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
1130 struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
1132 if (!hlist_empty(bucket))
1133 return bucket->first;
1137 EXPORT_SYMBOL(seq_hlist_next_percpu);
1139 void __init seq_file_init(void)
1141 seq_file_cache = KMEM_CACHE(seq_file, SLAB_ACCOUNT|SLAB_PANIC);