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9#include <linux/cache.h>
10#include <linux/fs.h>
11#include <linux/export.h>
12#include <linux/seq_file.h>
13#include <linux/vmalloc.h>
14#include <linux/slab.h>
15#include <linux/cred.h>
16#include <linux/mm.h>
17#include <linux/printk.h>
18#include <linux/string_helpers.h>
19
20#include <linux/uaccess.h>
21#include <asm/page.h>
22
23static struct kmem_cache *seq_file_cache __ro_after_init;
24
25static void seq_set_overflow(struct seq_file *m)
26{
27 m->count = m->size;
28}
29
30static void *seq_buf_alloc(unsigned long size)
31{
32 return kvmalloc(size, GFP_KERNEL_ACCOUNT);
33}
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51int seq_open(struct file *file, const struct seq_operations *op)
52{
53 struct seq_file *p;
54
55 WARN_ON(file->private_data);
56
57 p = kmem_cache_zalloc(seq_file_cache, GFP_KERNEL);
58 if (!p)
59 return -ENOMEM;
60
61 file->private_data = p;
62
63 mutex_init(&p->lock);
64 p->op = op;
65
66
67
68 p->file = file;
69
70
71
72
73
74
75 file->f_version = 0;
76
77
78
79
80
81
82
83
84
85
86 file->f_mode &= ~FMODE_PWRITE;
87 return 0;
88}
89EXPORT_SYMBOL(seq_open);
90
91static int traverse(struct seq_file *m, loff_t offset)
92{
93 loff_t pos = 0;
94 int error = 0;
95 void *p;
96
97 m->version = 0;
98 m->index = 0;
99 m->count = m->from = 0;
100 if (!offset)
101 return 0;
102
103 if (!m->buf) {
104 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
105 if (!m->buf)
106 return -ENOMEM;
107 }
108 p = m->op->start(m, &m->index);
109 while (p) {
110 error = PTR_ERR(p);
111 if (IS_ERR(p))
112 break;
113 error = m->op->show(m, p);
114 if (error < 0)
115 break;
116 if (unlikely(error)) {
117 error = 0;
118 m->count = 0;
119 }
120 if (seq_has_overflowed(m))
121 goto Eoverflow;
122 if (pos + m->count > offset) {
123 m->from = offset - pos;
124 m->count -= m->from;
125 break;
126 }
127 pos += m->count;
128 m->count = 0;
129 p = m->op->next(m, p, &m->index);
130 if (pos == offset)
131 break;
132 }
133 m->op->stop(m, p);
134 return error;
135
136Eoverflow:
137 m->op->stop(m, p);
138 kvfree(m->buf);
139 m->count = 0;
140 m->buf = seq_buf_alloc(m->size <<= 1);
141 return !m->buf ? -ENOMEM : -EAGAIN;
142}
143
144
145
146
147
148
149
150
151
152
153ssize_t seq_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
154{
155 struct seq_file *m = file->private_data;
156 size_t copied = 0;
157 size_t n;
158 void *p;
159 int err = 0;
160
161 mutex_lock(&m->lock);
162
163
164
165
166
167
168
169
170
171
172
173
174 m->version = file->f_version;
175
176
177
178
179
180 if (*ppos == 0) {
181 m->index = 0;
182 m->version = 0;
183 m->count = 0;
184 }
185
186
187 if (unlikely(*ppos != m->read_pos)) {
188 while ((err = traverse(m, *ppos)) == -EAGAIN)
189 ;
190 if (err) {
191
192 m->read_pos = 0;
193 m->version = 0;
194 m->index = 0;
195 m->count = 0;
196 goto Done;
197 } else {
198 m->read_pos = *ppos;
199 }
200 }
201
202
203 if (!m->buf) {
204 m->buf = seq_buf_alloc(m->size = PAGE_SIZE);
205 if (!m->buf)
206 goto Enomem;
207 }
208
209 if (m->count) {
210 n = min(m->count, size);
211 err = copy_to_user(buf, m->buf + m->from, n);
212 if (err)
213 goto Efault;
214 m->count -= n;
215 m->from += n;
216 size -= n;
217 buf += n;
218 copied += n;
219 if (!size)
220 goto Done;
221 }
222
223 m->from = 0;
224 p = m->op->start(m, &m->index);
225 while (1) {
226 err = PTR_ERR(p);
227 if (!p || IS_ERR(p))
228 break;
229 err = m->op->show(m, p);
230 if (err < 0)
231 break;
232 if (unlikely(err))
233 m->count = 0;
234 if (unlikely(!m->count)) {
235 p = m->op->next(m, p, &m->index);
236 continue;
237 }
238 if (m->count < m->size)
239 goto Fill;
240 m->op->stop(m, p);
241 kvfree(m->buf);
242 m->count = 0;
243 m->buf = seq_buf_alloc(m->size <<= 1);
244 if (!m->buf)
245 goto Enomem;
246 m->version = 0;
247 p = m->op->start(m, &m->index);
248 }
249 m->op->stop(m, p);
250 m->count = 0;
251 goto Done;
252Fill:
253
254 while (1) {
255 size_t offs = m->count;
256 loff_t pos = m->index;
257
258 p = m->op->next(m, p, &m->index);
259 if (pos == m->index)
260
261 m->index++;
262 if (!p || IS_ERR(p)) {
263 err = PTR_ERR(p);
264 break;
265 }
266 if (m->count >= size)
267 break;
268 err = m->op->show(m, p);
269 if (seq_has_overflowed(m) || err) {
270 m->count = offs;
271 if (likely(err <= 0))
272 break;
273 }
274 }
275 m->op->stop(m, p);
276 n = min(m->count, size);
277 err = copy_to_user(buf, m->buf, n);
278 if (err)
279 goto Efault;
280 copied += n;
281 m->count -= n;
282 m->from = n;
283Done:
284 if (!copied)
285 copied = err;
286 else {
287 *ppos += copied;
288 m->read_pos += copied;
289 }
290 file->f_version = m->version;
291 mutex_unlock(&m->lock);
292 return copied;
293Enomem:
294 err = -ENOMEM;
295 goto Done;
296Efault:
297 err = -EFAULT;
298 goto Done;
299}
300EXPORT_SYMBOL(seq_read);
301
302
303
304
305
306
307
308
309
310loff_t seq_lseek(struct file *file, loff_t offset, int whence)
311{
312 struct seq_file *m = file->private_data;
313 loff_t retval = -EINVAL;
314
315 mutex_lock(&m->lock);
316 m->version = file->f_version;
317 switch (whence) {
318 case SEEK_CUR:
319 offset += file->f_pos;
320
321 case SEEK_SET:
322 if (offset < 0)
323 break;
324 retval = offset;
325 if (offset != m->read_pos) {
326 while ((retval = traverse(m, offset)) == -EAGAIN)
327 ;
328 if (retval) {
329
330 file->f_pos = 0;
331 m->read_pos = 0;
332 m->version = 0;
333 m->index = 0;
334 m->count = 0;
335 } else {
336 m->read_pos = offset;
337 retval = file->f_pos = offset;
338 }
339 } else {
340 file->f_pos = offset;
341 }
342 }
343 file->f_version = m->version;
344 mutex_unlock(&m->lock);
345 return retval;
346}
347EXPORT_SYMBOL(seq_lseek);
348
349
350
351
352
353
354
355
356
357int seq_release(struct inode *inode, struct file *file)
358{
359 struct seq_file *m = file->private_data;
360 kvfree(m->buf);
361 kmem_cache_free(seq_file_cache, m);
362 return 0;
363}
364EXPORT_SYMBOL(seq_release);
365
366
367
368
369
370
371
372
373
374
375
376void seq_escape(struct seq_file *m, const char *s, const char *esc)
377{
378 char *buf;
379 size_t size = seq_get_buf(m, &buf);
380 int ret;
381
382 ret = string_escape_str(s, buf, size, ESCAPE_OCTAL, esc);
383 seq_commit(m, ret < size ? ret : -1);
384}
385EXPORT_SYMBOL(seq_escape);
386
387void seq_vprintf(struct seq_file *m, const char *f, va_list args)
388{
389 int len;
390
391 if (m->count < m->size) {
392 len = vsnprintf(m->buf + m->count, m->size - m->count, f, args);
393 if (m->count + len < m->size) {
394 m->count += len;
395 return;
396 }
397 }
398 seq_set_overflow(m);
399}
400EXPORT_SYMBOL(seq_vprintf);
401
402void seq_printf(struct seq_file *m, const char *f, ...)
403{
404 va_list args;
405
406 va_start(args, f);
407 seq_vprintf(m, f, args);
408 va_end(args);
409}
410EXPORT_SYMBOL(seq_printf);
411
412
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414
415
416
417
418
419
420
421
422
423char *mangle_path(char *s, const char *p, const char *esc)
424{
425 while (s <= p) {
426 char c = *p++;
427 if (!c) {
428 return s;
429 } else if (!strchr(esc, c)) {
430 *s++ = c;
431 } else if (s + 4 > p) {
432 break;
433 } else {
434 *s++ = '\\';
435 *s++ = '0' + ((c & 0300) >> 6);
436 *s++ = '0' + ((c & 070) >> 3);
437 *s++ = '0' + (c & 07);
438 }
439 }
440 return NULL;
441}
442EXPORT_SYMBOL(mangle_path);
443
444
445
446
447
448
449
450
451
452
453int seq_path(struct seq_file *m, const struct path *path, const char *esc)
454{
455 char *buf;
456 size_t size = seq_get_buf(m, &buf);
457 int res = -1;
458
459 if (size) {
460 char *p = d_path(path, buf, size);
461 if (!IS_ERR(p)) {
462 char *end = mangle_path(buf, p, esc);
463 if (end)
464 res = end - buf;
465 }
466 }
467 seq_commit(m, res);
468
469 return res;
470}
471EXPORT_SYMBOL(seq_path);
472
473
474
475
476
477
478
479
480
481int seq_file_path(struct seq_file *m, struct file *file, const char *esc)
482{
483 return seq_path(m, &file->f_path, esc);
484}
485EXPORT_SYMBOL(seq_file_path);
486
487
488
489
490int seq_path_root(struct seq_file *m, const struct path *path,
491 const struct path *root, const char *esc)
492{
493 char *buf;
494 size_t size = seq_get_buf(m, &buf);
495 int res = -ENAMETOOLONG;
496
497 if (size) {
498 char *p;
499
500 p = __d_path(path, root, buf, size);
501 if (!p)
502 return SEQ_SKIP;
503 res = PTR_ERR(p);
504 if (!IS_ERR(p)) {
505 char *end = mangle_path(buf, p, esc);
506 if (end)
507 res = end - buf;
508 else
509 res = -ENAMETOOLONG;
510 }
511 }
512 seq_commit(m, res);
513
514 return res < 0 && res != -ENAMETOOLONG ? res : 0;
515}
516
517
518
519
520int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
521{
522 char *buf;
523 size_t size = seq_get_buf(m, &buf);
524 int res = -1;
525
526 if (size) {
527 char *p = dentry_path(dentry, buf, size);
528 if (!IS_ERR(p)) {
529 char *end = mangle_path(buf, p, esc);
530 if (end)
531 res = end - buf;
532 }
533 }
534 seq_commit(m, res);
535
536 return res;
537}
538EXPORT_SYMBOL(seq_dentry);
539
540static void *single_start(struct seq_file *p, loff_t *pos)
541{
542 return NULL + (*pos == 0);
543}
544
545static void *single_next(struct seq_file *p, void *v, loff_t *pos)
546{
547 ++*pos;
548 return NULL;
549}
550
551static void single_stop(struct seq_file *p, void *v)
552{
553}
554
555int single_open(struct file *file, int (*show)(struct seq_file *, void *),
556 void *data)
557{
558 struct seq_operations *op = kmalloc(sizeof(*op), GFP_KERNEL_ACCOUNT);
559 int res = -ENOMEM;
560
561 if (op) {
562 op->start = single_start;
563 op->next = single_next;
564 op->stop = single_stop;
565 op->show = show;
566 res = seq_open(file, op);
567 if (!res)
568 ((struct seq_file *)file->private_data)->private = data;
569 else
570 kfree(op);
571 }
572 return res;
573}
574EXPORT_SYMBOL(single_open);
575
576int single_open_size(struct file *file, int (*show)(struct seq_file *, void *),
577 void *data, size_t size)
578{
579 char *buf = seq_buf_alloc(size);
580 int ret;
581 if (!buf)
582 return -ENOMEM;
583 ret = single_open(file, show, data);
584 if (ret) {
585 kvfree(buf);
586 return ret;
587 }
588 ((struct seq_file *)file->private_data)->buf = buf;
589 ((struct seq_file *)file->private_data)->size = size;
590 return 0;
591}
592EXPORT_SYMBOL(single_open_size);
593
594int single_release(struct inode *inode, struct file *file)
595{
596 const struct seq_operations *op = ((struct seq_file *)file->private_data)->op;
597 int res = seq_release(inode, file);
598 kfree(op);
599 return res;
600}
601EXPORT_SYMBOL(single_release);
602
603int seq_release_private(struct inode *inode, struct file *file)
604{
605 struct seq_file *seq = file->private_data;
606
607 kfree(seq->private);
608 seq->private = NULL;
609 return seq_release(inode, file);
610}
611EXPORT_SYMBOL(seq_release_private);
612
613void *__seq_open_private(struct file *f, const struct seq_operations *ops,
614 int psize)
615{
616 int rc;
617 void *private;
618 struct seq_file *seq;
619
620 private = kzalloc(psize, GFP_KERNEL_ACCOUNT);
621 if (private == NULL)
622 goto out;
623
624 rc = seq_open(f, ops);
625 if (rc < 0)
626 goto out_free;
627
628 seq = f->private_data;
629 seq->private = private;
630 return private;
631
632out_free:
633 kfree(private);
634out:
635 return NULL;
636}
637EXPORT_SYMBOL(__seq_open_private);
638
639int seq_open_private(struct file *filp, const struct seq_operations *ops,
640 int psize)
641{
642 return __seq_open_private(filp, ops, psize) ? 0 : -ENOMEM;
643}
644EXPORT_SYMBOL(seq_open_private);
645
646void seq_putc(struct seq_file *m, char c)
647{
648 if (m->count >= m->size)
649 return;
650
651 m->buf[m->count++] = c;
652}
653EXPORT_SYMBOL(seq_putc);
654
655void seq_puts(struct seq_file *m, const char *s)
656{
657 int len = strlen(s);
658
659 if (m->count + len >= m->size) {
660 seq_set_overflow(m);
661 return;
662 }
663 memcpy(m->buf + m->count, s, len);
664 m->count += len;
665}
666EXPORT_SYMBOL(seq_puts);
667
668
669
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677
678
679
680void seq_put_decimal_ull_width(struct seq_file *m, const char *delimiter,
681 unsigned long long num, unsigned int width)
682{
683 int len;
684
685 if (m->count + 2 >= m->size)
686 goto overflow;
687
688 if (delimiter && delimiter[0]) {
689 if (delimiter[1] == 0)
690 seq_putc(m, delimiter[0]);
691 else
692 seq_puts(m, delimiter);
693 }
694
695 if (!width)
696 width = 1;
697
698 if (m->count + width >= m->size)
699 goto overflow;
700
701 len = num_to_str(m->buf + m->count, m->size - m->count, num, width);
702 if (!len)
703 goto overflow;
704
705 m->count += len;
706 return;
707
708overflow:
709 seq_set_overflow(m);
710}
711
712void seq_put_decimal_ull(struct seq_file *m, const char *delimiter,
713 unsigned long long num)
714{
715 return seq_put_decimal_ull_width(m, delimiter, num, 0);
716}
717EXPORT_SYMBOL(seq_put_decimal_ull);
718
719
720
721
722
723
724
725
726
727
728
729
730
731void seq_put_hex_ll(struct seq_file *m, const char *delimiter,
732 unsigned long long v, unsigned int width)
733{
734 unsigned int len;
735 int i;
736
737 if (delimiter && delimiter[0]) {
738 if (delimiter[1] == 0)
739 seq_putc(m, delimiter[0]);
740 else
741 seq_puts(m, delimiter);
742 }
743
744
745 if (v == 0)
746 len = 1;
747 else
748 len = (sizeof(v) * 8 - __builtin_clzll(v) + 3) / 4;
749
750 if (len < width)
751 len = width;
752
753 if (m->count + len > m->size) {
754 seq_set_overflow(m);
755 return;
756 }
757
758 for (i = len - 1; i >= 0; i--) {
759 m->buf[m->count + i] = hex_asc[0xf & v];
760 v = v >> 4;
761 }
762 m->count += len;
763}
764
765void seq_put_decimal_ll(struct seq_file *m, const char *delimiter, long long num)
766{
767 int len;
768
769 if (m->count + 3 >= m->size)
770 goto overflow;
771
772 if (delimiter && delimiter[0]) {
773 if (delimiter[1] == 0)
774 seq_putc(m, delimiter[0]);
775 else
776 seq_puts(m, delimiter);
777 }
778
779 if (m->count + 2 >= m->size)
780 goto overflow;
781
782 if (num < 0) {
783 m->buf[m->count++] = '-';
784 num = -num;
785 }
786
787 if (num < 10) {
788 m->buf[m->count++] = num + '0';
789 return;
790 }
791
792 len = num_to_str(m->buf + m->count, m->size - m->count, num, 0);
793 if (!len)
794 goto overflow;
795
796 m->count += len;
797 return;
798
799overflow:
800 seq_set_overflow(m);
801}
802EXPORT_SYMBOL(seq_put_decimal_ll);
803
804
805
806
807
808
809
810
811
812int seq_write(struct seq_file *seq, const void *data, size_t len)
813{
814 if (seq->count + len < seq->size) {
815 memcpy(seq->buf + seq->count, data, len);
816 seq->count += len;
817 return 0;
818 }
819 seq_set_overflow(seq);
820 return -1;
821}
822EXPORT_SYMBOL(seq_write);
823
824
825
826
827
828
829void seq_pad(struct seq_file *m, char c)
830{
831 int size = m->pad_until - m->count;
832 if (size > 0) {
833 if (size + m->count > m->size) {
834 seq_set_overflow(m);
835 return;
836 }
837 memset(m->buf + m->count, ' ', size);
838 m->count += size;
839 }
840 if (c)
841 seq_putc(m, c);
842}
843EXPORT_SYMBOL(seq_pad);
844
845
846void seq_hex_dump(struct seq_file *m, const char *prefix_str, int prefix_type,
847 int rowsize, int groupsize, const void *buf, size_t len,
848 bool ascii)
849{
850 const u8 *ptr = buf;
851 int i, linelen, remaining = len;
852 char *buffer;
853 size_t size;
854 int ret;
855
856 if (rowsize != 16 && rowsize != 32)
857 rowsize = 16;
858
859 for (i = 0; i < len && !seq_has_overflowed(m); i += rowsize) {
860 linelen = min(remaining, rowsize);
861 remaining -= rowsize;
862
863 switch (prefix_type) {
864 case DUMP_PREFIX_ADDRESS:
865 seq_printf(m, "%s%p: ", prefix_str, ptr + i);
866 break;
867 case DUMP_PREFIX_OFFSET:
868 seq_printf(m, "%s%.8x: ", prefix_str, i);
869 break;
870 default:
871 seq_printf(m, "%s", prefix_str);
872 break;
873 }
874
875 size = seq_get_buf(m, &buffer);
876 ret = hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
877 buffer, size, ascii);
878 seq_commit(m, ret < size ? ret : -1);
879
880 seq_putc(m, '\n');
881 }
882}
883EXPORT_SYMBOL(seq_hex_dump);
884
885struct list_head *seq_list_start(struct list_head *head, loff_t pos)
886{
887 struct list_head *lh;
888
889 list_for_each(lh, head)
890 if (pos-- == 0)
891 return lh;
892
893 return NULL;
894}
895EXPORT_SYMBOL(seq_list_start);
896
897struct list_head *seq_list_start_head(struct list_head *head, loff_t pos)
898{
899 if (!pos)
900 return head;
901
902 return seq_list_start(head, pos - 1);
903}
904EXPORT_SYMBOL(seq_list_start_head);
905
906struct list_head *seq_list_next(void *v, struct list_head *head, loff_t *ppos)
907{
908 struct list_head *lh;
909
910 lh = ((struct list_head *)v)->next;
911 ++*ppos;
912 return lh == head ? NULL : lh;
913}
914EXPORT_SYMBOL(seq_list_next);
915
916
917
918
919
920
921
922
923struct hlist_node *seq_hlist_start(struct hlist_head *head, loff_t pos)
924{
925 struct hlist_node *node;
926
927 hlist_for_each(node, head)
928 if (pos-- == 0)
929 return node;
930 return NULL;
931}
932EXPORT_SYMBOL(seq_hlist_start);
933
934
935
936
937
938
939
940
941
942struct hlist_node *seq_hlist_start_head(struct hlist_head *head, loff_t pos)
943{
944 if (!pos)
945 return SEQ_START_TOKEN;
946
947 return seq_hlist_start(head, pos - 1);
948}
949EXPORT_SYMBOL(seq_hlist_start_head);
950
951
952
953
954
955
956
957
958
959struct hlist_node *seq_hlist_next(void *v, struct hlist_head *head,
960 loff_t *ppos)
961{
962 struct hlist_node *node = v;
963
964 ++*ppos;
965 if (v == SEQ_START_TOKEN)
966 return head->first;
967 else
968 return node->next;
969}
970EXPORT_SYMBOL(seq_hlist_next);
971
972
973
974
975
976
977
978
979
980
981
982
983struct hlist_node *seq_hlist_start_rcu(struct hlist_head *head,
984 loff_t pos)
985{
986 struct hlist_node *node;
987
988 __hlist_for_each_rcu(node, head)
989 if (pos-- == 0)
990 return node;
991 return NULL;
992}
993EXPORT_SYMBOL(seq_hlist_start_rcu);
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007struct hlist_node *seq_hlist_start_head_rcu(struct hlist_head *head,
1008 loff_t pos)
1009{
1010 if (!pos)
1011 return SEQ_START_TOKEN;
1012
1013 return seq_hlist_start_rcu(head, pos - 1);
1014}
1015EXPORT_SYMBOL(seq_hlist_start_head_rcu);
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029struct hlist_node *seq_hlist_next_rcu(void *v,
1030 struct hlist_head *head,
1031 loff_t *ppos)
1032{
1033 struct hlist_node *node = v;
1034
1035 ++*ppos;
1036 if (v == SEQ_START_TOKEN)
1037 return rcu_dereference(head->first);
1038 else
1039 return rcu_dereference(node->next);
1040}
1041EXPORT_SYMBOL(seq_hlist_next_rcu);
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051struct hlist_node *
1052seq_hlist_start_percpu(struct hlist_head __percpu *head, int *cpu, loff_t pos)
1053{
1054 struct hlist_node *node;
1055
1056 for_each_possible_cpu(*cpu) {
1057 hlist_for_each(node, per_cpu_ptr(head, *cpu)) {
1058 if (pos-- == 0)
1059 return node;
1060 }
1061 }
1062 return NULL;
1063}
1064EXPORT_SYMBOL(seq_hlist_start_percpu);
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075struct hlist_node *
1076seq_hlist_next_percpu(void *v, struct hlist_head __percpu *head,
1077 int *cpu, loff_t *pos)
1078{
1079 struct hlist_node *node = v;
1080
1081 ++*pos;
1082
1083 if (node->next)
1084 return node->next;
1085
1086 for (*cpu = cpumask_next(*cpu, cpu_possible_mask); *cpu < nr_cpu_ids;
1087 *cpu = cpumask_next(*cpu, cpu_possible_mask)) {
1088 struct hlist_head *bucket = per_cpu_ptr(head, *cpu);
1089
1090 if (!hlist_empty(bucket))
1091 return bucket->first;
1092 }
1093 return NULL;
1094}
1095EXPORT_SYMBOL(seq_hlist_next_percpu);
1096
1097void __init seq_file_init(void)
1098{
1099 seq_file_cache = KMEM_CACHE(seq_file, SLAB_ACCOUNT|SLAB_PANIC);
1100}
1101