2 * fs/kernfs/file.c - kernfs file implementation
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
8 * This file is released under the GPLv2.
12 #include <linux/seq_file.h>
13 #include <linux/slab.h>
14 #include <linux/poll.h>
15 #include <linux/pagemap.h>
16 #include <linux/sched.h>
17 #include <linux/fsnotify.h>
19 #include "kernfs-internal.h"
22 * There's one kernfs_open_file for each open file and one kernfs_open_node
23 * for each kernfs_node with one or more open files.
25 * kernfs_node->attr.open points to kernfs_open_node. attr.open is
26 * protected by kernfs_open_node_lock.
28 * filp->private_data points to seq_file whose ->private points to
29 * kernfs_open_file. kernfs_open_files are chained at
30 * kernfs_open_node->files, which is protected by kernfs_open_file_mutex.
32 static DEFINE_SPINLOCK(kernfs_open_node_lock
);
33 static DEFINE_MUTEX(kernfs_open_file_mutex
);
35 struct kernfs_open_node
{
38 wait_queue_head_t poll
;
39 struct list_head files
; /* goes through kernfs_open_file.list */
43 * kernfs_notify() may be called from any context and bounces notifications
44 * through a work item. To minimize space overhead in kernfs_node, the
45 * pending queue is implemented as a singly linked list of kernfs_nodes.
46 * The list is terminated with the self pointer so that whether a
47 * kernfs_node is on the list or not can be determined by testing the next
50 #define KERNFS_NOTIFY_EOL ((void *)&kernfs_notify_list)
52 static DEFINE_SPINLOCK(kernfs_notify_lock
);
53 static struct kernfs_node
*kernfs_notify_list
= KERNFS_NOTIFY_EOL
;
55 static struct kernfs_open_file
*kernfs_of(struct file
*file
)
57 return ((struct seq_file
*)file
->private_data
)->private;
61 * Determine the kernfs_ops for the given kernfs_node. This function must
62 * be called while holding an active reference.
64 static const struct kernfs_ops
*kernfs_ops(struct kernfs_node
*kn
)
66 if (kn
->flags
& KERNFS_LOCKDEP
)
67 lockdep_assert_held(kn
);
72 * As kernfs_seq_stop() is also called after kernfs_seq_start() or
73 * kernfs_seq_next() failure, it needs to distinguish whether it's stopping
74 * a seq_file iteration which is fully initialized with an active reference
75 * or an aborted kernfs_seq_start() due to get_active failure. The
76 * position pointer is the only context for each seq_file iteration and
77 * thus the stop condition should be encoded in it. As the return value is
78 * directly visible to userland, ERR_PTR(-ENODEV) is the only acceptable
79 * choice to indicate get_active failure.
81 * Unfortunately, this is complicated due to the optional custom seq_file
82 * operations which may return ERR_PTR(-ENODEV) too. kernfs_seq_stop()
83 * can't distinguish whether ERR_PTR(-ENODEV) is from get_active failure or
84 * custom seq_file operations and thus can't decide whether put_active
85 * should be performed or not only on ERR_PTR(-ENODEV).
87 * This is worked around by factoring out the custom seq_stop() and
88 * put_active part into kernfs_seq_stop_active(), skipping it from
89 * kernfs_seq_stop() if ERR_PTR(-ENODEV) while invoking it directly after
90 * custom seq_file operations fail with ERR_PTR(-ENODEV) - this ensures
91 * that kernfs_seq_stop_active() is skipped only after get_active failure.
93 static void kernfs_seq_stop_active(struct seq_file
*sf
, void *v
)
95 struct kernfs_open_file
*of
= sf
->private;
96 const struct kernfs_ops
*ops
= kernfs_ops(of
->kn
);
100 kernfs_put_active(of
->kn
);
103 static void *kernfs_seq_start(struct seq_file
*sf
, loff_t
*ppos
)
105 struct kernfs_open_file
*of
= sf
->private;
106 const struct kernfs_ops
*ops
;
109 * @of->mutex nests outside active ref and is just to ensure that
110 * the ops aren't called concurrently for the same open file.
112 mutex_lock(&of
->mutex
);
113 if (!kernfs_get_active(of
->kn
))
114 return ERR_PTR(-ENODEV
);
116 ops
= kernfs_ops(of
->kn
);
117 if (ops
->seq_start
) {
118 void *next
= ops
->seq_start(sf
, ppos
);
119 /* see the comment above kernfs_seq_stop_active() */
120 if (next
== ERR_PTR(-ENODEV
))
121 kernfs_seq_stop_active(sf
, next
);
125 * The same behavior and code as single_open(). Returns
126 * !NULL if pos is at the beginning; otherwise, NULL.
128 return NULL
+ !*ppos
;
132 static void *kernfs_seq_next(struct seq_file
*sf
, void *v
, loff_t
*ppos
)
134 struct kernfs_open_file
*of
= sf
->private;
135 const struct kernfs_ops
*ops
= kernfs_ops(of
->kn
);
138 void *next
= ops
->seq_next(sf
, v
, ppos
);
139 /* see the comment above kernfs_seq_stop_active() */
140 if (next
== ERR_PTR(-ENODEV
))
141 kernfs_seq_stop_active(sf
, next
);
145 * The same behavior and code as single_open(), always
146 * terminate after the initial read.
153 static void kernfs_seq_stop(struct seq_file
*sf
, void *v
)
155 struct kernfs_open_file
*of
= sf
->private;
157 if (v
!= ERR_PTR(-ENODEV
))
158 kernfs_seq_stop_active(sf
, v
);
159 mutex_unlock(&of
->mutex
);
162 static int kernfs_seq_show(struct seq_file
*sf
, void *v
)
164 struct kernfs_open_file
*of
= sf
->private;
166 of
->event
= atomic_read(&of
->kn
->attr
.open
->event
);
168 return of
->kn
->attr
.ops
->seq_show(sf
, v
);
171 static const struct seq_operations kernfs_seq_ops
= {
172 .start
= kernfs_seq_start
,
173 .next
= kernfs_seq_next
,
174 .stop
= kernfs_seq_stop
,
175 .show
= kernfs_seq_show
,
179 * As reading a bin file can have side-effects, the exact offset and bytes
180 * specified in read(2) call should be passed to the read callback making
181 * it difficult to use seq_file. Implement simplistic custom buffering for
184 static ssize_t
kernfs_file_direct_read(struct kernfs_open_file
*of
,
185 char __user
*user_buf
, size_t count
,
188 ssize_t len
= min_t(size_t, count
, PAGE_SIZE
);
189 const struct kernfs_ops
*ops
;
192 buf
= kmalloc(len
, GFP_KERNEL
);
197 * @of->mutex nests outside active ref and is just to ensure that
198 * the ops aren't called concurrently for the same open file.
200 mutex_lock(&of
->mutex
);
201 if (!kernfs_get_active(of
->kn
)) {
203 mutex_unlock(&of
->mutex
);
207 ops
= kernfs_ops(of
->kn
);
209 len
= ops
->read(of
, buf
, len
, *ppos
);
213 kernfs_put_active(of
->kn
);
214 mutex_unlock(&of
->mutex
);
219 if (copy_to_user(user_buf
, buf
, len
)) {
232 * kernfs_fop_read - kernfs vfs read callback
233 * @file: file pointer
234 * @user_buf: data to write
235 * @count: number of bytes
236 * @ppos: starting offset
238 static ssize_t
kernfs_fop_read(struct file
*file
, char __user
*user_buf
,
239 size_t count
, loff_t
*ppos
)
241 struct kernfs_open_file
*of
= kernfs_of(file
);
243 if (of
->kn
->flags
& KERNFS_HAS_SEQ_SHOW
)
244 return seq_read(file
, user_buf
, count
, ppos
);
246 return kernfs_file_direct_read(of
, user_buf
, count
, ppos
);
250 * kernfs_fop_write - kernfs vfs write callback
251 * @file: file pointer
252 * @user_buf: data to write
253 * @count: number of bytes
254 * @ppos: starting offset
256 * Copy data in from userland and pass it to the matching kernfs write
259 * There is no easy way for us to know if userspace is only doing a partial
260 * write, so we don't support them. We expect the entire buffer to come on
261 * the first write. Hint: if you're writing a value, first read the file,
262 * modify only the the value you're changing, then write entire buffer
265 static ssize_t
kernfs_fop_write(struct file
*file
, const char __user
*user_buf
,
266 size_t count
, loff_t
*ppos
)
268 struct kernfs_open_file
*of
= kernfs_of(file
);
269 const struct kernfs_ops
*ops
;
273 if (of
->atomic_write_len
) {
275 if (len
> of
->atomic_write_len
)
278 len
= min_t(size_t, count
, PAGE_SIZE
);
281 buf
= kmalloc(len
+ 1, GFP_KERNEL
);
285 if (copy_from_user(buf
, user_buf
, len
)) {
289 buf
[len
] = '\0'; /* guarantee string termination */
292 * @of->mutex nests outside active ref and is just to ensure that
293 * the ops aren't called concurrently for the same open file.
295 mutex_lock(&of
->mutex
);
296 if (!kernfs_get_active(of
->kn
)) {
297 mutex_unlock(&of
->mutex
);
302 ops
= kernfs_ops(of
->kn
);
304 len
= ops
->write(of
, buf
, len
, *ppos
);
308 kernfs_put_active(of
->kn
);
309 mutex_unlock(&of
->mutex
);
318 static void kernfs_vma_open(struct vm_area_struct
*vma
)
320 struct file
*file
= vma
->vm_file
;
321 struct kernfs_open_file
*of
= kernfs_of(file
);
326 if (!kernfs_get_active(of
->kn
))
329 if (of
->vm_ops
->open
)
330 of
->vm_ops
->open(vma
);
332 kernfs_put_active(of
->kn
);
335 static int kernfs_vma_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
337 struct file
*file
= vma
->vm_file
;
338 struct kernfs_open_file
*of
= kernfs_of(file
);
342 return VM_FAULT_SIGBUS
;
344 if (!kernfs_get_active(of
->kn
))
345 return VM_FAULT_SIGBUS
;
347 ret
= VM_FAULT_SIGBUS
;
348 if (of
->vm_ops
->fault
)
349 ret
= of
->vm_ops
->fault(vma
, vmf
);
351 kernfs_put_active(of
->kn
);
355 static int kernfs_vma_page_mkwrite(struct vm_area_struct
*vma
,
356 struct vm_fault
*vmf
)
358 struct file
*file
= vma
->vm_file
;
359 struct kernfs_open_file
*of
= kernfs_of(file
);
363 return VM_FAULT_SIGBUS
;
365 if (!kernfs_get_active(of
->kn
))
366 return VM_FAULT_SIGBUS
;
369 if (of
->vm_ops
->page_mkwrite
)
370 ret
= of
->vm_ops
->page_mkwrite(vma
, vmf
);
372 file_update_time(file
);
374 kernfs_put_active(of
->kn
);
378 static int kernfs_vma_access(struct vm_area_struct
*vma
, unsigned long addr
,
379 void *buf
, int len
, int write
)
381 struct file
*file
= vma
->vm_file
;
382 struct kernfs_open_file
*of
= kernfs_of(file
);
388 if (!kernfs_get_active(of
->kn
))
392 if (of
->vm_ops
->access
)
393 ret
= of
->vm_ops
->access(vma
, addr
, buf
, len
, write
);
395 kernfs_put_active(of
->kn
);
400 static int kernfs_vma_set_policy(struct vm_area_struct
*vma
,
401 struct mempolicy
*new)
403 struct file
*file
= vma
->vm_file
;
404 struct kernfs_open_file
*of
= kernfs_of(file
);
410 if (!kernfs_get_active(of
->kn
))
414 if (of
->vm_ops
->set_policy
)
415 ret
= of
->vm_ops
->set_policy(vma
, new);
417 kernfs_put_active(of
->kn
);
421 static struct mempolicy
*kernfs_vma_get_policy(struct vm_area_struct
*vma
,
424 struct file
*file
= vma
->vm_file
;
425 struct kernfs_open_file
*of
= kernfs_of(file
);
426 struct mempolicy
*pol
;
429 return vma
->vm_policy
;
431 if (!kernfs_get_active(of
->kn
))
432 return vma
->vm_policy
;
434 pol
= vma
->vm_policy
;
435 if (of
->vm_ops
->get_policy
)
436 pol
= of
->vm_ops
->get_policy(vma
, addr
);
438 kernfs_put_active(of
->kn
);
442 static int kernfs_vma_migrate(struct vm_area_struct
*vma
,
443 const nodemask_t
*from
, const nodemask_t
*to
,
446 struct file
*file
= vma
->vm_file
;
447 struct kernfs_open_file
*of
= kernfs_of(file
);
453 if (!kernfs_get_active(of
->kn
))
457 if (of
->vm_ops
->migrate
)
458 ret
= of
->vm_ops
->migrate(vma
, from
, to
, flags
);
460 kernfs_put_active(of
->kn
);
465 static const struct vm_operations_struct kernfs_vm_ops
= {
466 .open
= kernfs_vma_open
,
467 .fault
= kernfs_vma_fault
,
468 .page_mkwrite
= kernfs_vma_page_mkwrite
,
469 .access
= kernfs_vma_access
,
471 .set_policy
= kernfs_vma_set_policy
,
472 .get_policy
= kernfs_vma_get_policy
,
473 .migrate
= kernfs_vma_migrate
,
477 static int kernfs_fop_mmap(struct file
*file
, struct vm_area_struct
*vma
)
479 struct kernfs_open_file
*of
= kernfs_of(file
);
480 const struct kernfs_ops
*ops
;
484 * mmap path and of->mutex are prone to triggering spurious lockdep
485 * warnings and we don't want to add spurious locking dependency
486 * between the two. Check whether mmap is actually implemented
487 * without grabbing @of->mutex by testing HAS_MMAP flag. See the
488 * comment in kernfs_file_open() for more details.
490 if (!(of
->kn
->flags
& KERNFS_HAS_MMAP
))
493 mutex_lock(&of
->mutex
);
496 if (!kernfs_get_active(of
->kn
))
499 ops
= kernfs_ops(of
->kn
);
500 rc
= ops
->mmap(of
, vma
);
505 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
506 * to satisfy versions of X which crash if the mmap fails: that
507 * substitutes a new vm_file, and we don't then want bin_vm_ops.
509 if (vma
->vm_file
!= file
)
513 if (of
->mmapped
&& of
->vm_ops
!= vma
->vm_ops
)
517 * It is not possible to successfully wrap close.
518 * So error if someone is trying to use close.
521 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
526 of
->vm_ops
= vma
->vm_ops
;
527 vma
->vm_ops
= &kernfs_vm_ops
;
529 kernfs_put_active(of
->kn
);
531 mutex_unlock(&of
->mutex
);
537 * kernfs_get_open_node - get or create kernfs_open_node
538 * @kn: target kernfs_node
539 * @of: kernfs_open_file for this instance of open
541 * If @kn->attr.open exists, increment its reference count; otherwise,
542 * create one. @of is chained to the files list.
545 * Kernel thread context (may sleep).
548 * 0 on success, -errno on failure.
550 static int kernfs_get_open_node(struct kernfs_node
*kn
,
551 struct kernfs_open_file
*of
)
553 struct kernfs_open_node
*on
, *new_on
= NULL
;
556 mutex_lock(&kernfs_open_file_mutex
);
557 spin_lock_irq(&kernfs_open_node_lock
);
559 if (!kn
->attr
.open
&& new_on
) {
560 kn
->attr
.open
= new_on
;
566 atomic_inc(&on
->refcnt
);
567 list_add_tail(&of
->list
, &on
->files
);
570 spin_unlock_irq(&kernfs_open_node_lock
);
571 mutex_unlock(&kernfs_open_file_mutex
);
578 /* not there, initialize a new one and retry */
579 new_on
= kmalloc(sizeof(*new_on
), GFP_KERNEL
);
583 atomic_set(&new_on
->refcnt
, 0);
584 atomic_set(&new_on
->event
, 1);
585 init_waitqueue_head(&new_on
->poll
);
586 INIT_LIST_HEAD(&new_on
->files
);
591 * kernfs_put_open_node - put kernfs_open_node
592 * @kn: target kernfs_nodet
593 * @of: associated kernfs_open_file
595 * Put @kn->attr.open and unlink @of from the files list. If
596 * reference count reaches zero, disassociate and free it.
601 static void kernfs_put_open_node(struct kernfs_node
*kn
,
602 struct kernfs_open_file
*of
)
604 struct kernfs_open_node
*on
= kn
->attr
.open
;
607 mutex_lock(&kernfs_open_file_mutex
);
608 spin_lock_irqsave(&kernfs_open_node_lock
, flags
);
613 if (atomic_dec_and_test(&on
->refcnt
))
614 kn
->attr
.open
= NULL
;
618 spin_unlock_irqrestore(&kernfs_open_node_lock
, flags
);
619 mutex_unlock(&kernfs_open_file_mutex
);
624 static int kernfs_fop_open(struct inode
*inode
, struct file
*file
)
626 struct kernfs_node
*kn
= file
->f_path
.dentry
->d_fsdata
;
627 struct kernfs_root
*root
= kernfs_root(kn
);
628 const struct kernfs_ops
*ops
;
629 struct kernfs_open_file
*of
;
630 bool has_read
, has_write
, has_mmap
;
633 if (!kernfs_get_active(kn
))
636 ops
= kernfs_ops(kn
);
638 has_read
= ops
->seq_show
|| ops
->read
|| ops
->mmap
;
639 has_write
= ops
->write
|| ops
->mmap
;
640 has_mmap
= ops
->mmap
;
642 /* see the flag definition for details */
643 if (root
->flags
& KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK
) {
644 if ((file
->f_mode
& FMODE_WRITE
) &&
645 (!(inode
->i_mode
& S_IWUGO
) || !has_write
))
648 if ((file
->f_mode
& FMODE_READ
) &&
649 (!(inode
->i_mode
& S_IRUGO
) || !has_read
))
653 /* allocate a kernfs_open_file for the file */
655 of
= kzalloc(sizeof(struct kernfs_open_file
), GFP_KERNEL
);
660 * The following is done to give a different lockdep key to
661 * @of->mutex for files which implement mmap. This is a rather
662 * crude way to avoid false positive lockdep warning around
663 * mm->mmap_sem - mmap nests @of->mutex under mm->mmap_sem and
664 * reading /sys/block/sda/trace/act_mask grabs sr_mutex, under
665 * which mm->mmap_sem nests, while holding @of->mutex. As each
666 * open file has a separate mutex, it's okay as long as those don't
667 * happen on the same file. At this point, we can't easily give
668 * each file a separate locking class. Let's differentiate on
669 * whether the file has mmap or not for now.
671 * Both paths of the branch look the same. They're supposed to
672 * look that way and give @of->mutex different static lockdep keys.
675 mutex_init(&of
->mutex
);
677 mutex_init(&of
->mutex
);
683 * Write path needs to atomic_write_len outside active reference.
684 * Cache it in open_file. See kernfs_fop_write() for details.
686 of
->atomic_write_len
= ops
->atomic_write_len
;
689 * Always instantiate seq_file even if read access doesn't use
690 * seq_file or is not requested. This unifies private data access
691 * and readable regular files are the vast majority anyway.
694 error
= seq_open(file
, &kernfs_seq_ops
);
696 error
= seq_open(file
, NULL
);
700 ((struct seq_file
*)file
->private_data
)->private = of
;
702 /* seq_file clears PWRITE unconditionally, restore it if WRITE */
703 if (file
->f_mode
& FMODE_WRITE
)
704 file
->f_mode
|= FMODE_PWRITE
;
706 /* make sure we have open node struct */
707 error
= kernfs_get_open_node(kn
, of
);
711 /* open succeeded, put active references */
712 kernfs_put_active(kn
);
716 seq_release(inode
, file
);
720 kernfs_put_active(kn
);
724 static int kernfs_fop_release(struct inode
*inode
, struct file
*filp
)
726 struct kernfs_node
*kn
= filp
->f_path
.dentry
->d_fsdata
;
727 struct kernfs_open_file
*of
= kernfs_of(filp
);
729 kernfs_put_open_node(kn
, of
);
730 seq_release(inode
, filp
);
736 void kernfs_unmap_bin_file(struct kernfs_node
*kn
)
738 struct kernfs_open_node
*on
;
739 struct kernfs_open_file
*of
;
741 if (!(kn
->flags
& KERNFS_HAS_MMAP
))
744 spin_lock_irq(&kernfs_open_node_lock
);
747 atomic_inc(&on
->refcnt
);
748 spin_unlock_irq(&kernfs_open_node_lock
);
752 mutex_lock(&kernfs_open_file_mutex
);
753 list_for_each_entry(of
, &on
->files
, list
) {
754 struct inode
*inode
= file_inode(of
->file
);
755 unmap_mapping_range(inode
->i_mapping
, 0, 0, 1);
757 mutex_unlock(&kernfs_open_file_mutex
);
759 kernfs_put_open_node(kn
, NULL
);
763 * Kernfs attribute files are pollable. The idea is that you read
764 * the content and then you use 'poll' or 'select' to wait for
765 * the content to change. When the content changes (assuming the
766 * manager for the kobject supports notification), poll will
767 * return POLLERR|POLLPRI, and select will return the fd whether
768 * it is waiting for read, write, or exceptions.
769 * Once poll/select indicates that the value has changed, you
770 * need to close and re-open the file, or seek to 0 and read again.
771 * Reminder: this only works for attributes which actively support
772 * it, and it is not possible to test an attribute from userspace
773 * to see if it supports poll (Neither 'poll' nor 'select' return
774 * an appropriate error code). When in doubt, set a suitable timeout value.
776 static unsigned int kernfs_fop_poll(struct file
*filp
, poll_table
*wait
)
778 struct kernfs_open_file
*of
= kernfs_of(filp
);
779 struct kernfs_node
*kn
= filp
->f_path
.dentry
->d_fsdata
;
780 struct kernfs_open_node
*on
= kn
->attr
.open
;
782 /* need parent for the kobj, grab both */
783 if (!kernfs_get_active(kn
))
786 poll_wait(filp
, &on
->poll
, wait
);
788 kernfs_put_active(kn
);
790 if (of
->event
!= atomic_read(&on
->event
))
793 return DEFAULT_POLLMASK
;
796 return DEFAULT_POLLMASK
|POLLERR
|POLLPRI
;
799 static void kernfs_notify_workfn(struct work_struct
*work
)
801 struct kernfs_node
*kn
;
802 struct kernfs_open_node
*on
;
803 struct kernfs_super_info
*info
;
805 /* pop one off the notify_list */
806 spin_lock_irq(&kernfs_notify_lock
);
807 kn
= kernfs_notify_list
;
808 if (kn
== KERNFS_NOTIFY_EOL
) {
809 spin_unlock_irq(&kernfs_notify_lock
);
812 kernfs_notify_list
= kn
->attr
.notify_next
;
813 kn
->attr
.notify_next
= NULL
;
814 spin_unlock_irq(&kernfs_notify_lock
);
817 spin_lock_irq(&kernfs_open_node_lock
);
821 atomic_inc(&on
->event
);
822 wake_up_interruptible(&on
->poll
);
825 spin_unlock_irq(&kernfs_open_node_lock
);
828 mutex_lock(&kernfs_mutex
);
830 list_for_each_entry(info
, &kernfs_root(kn
)->supers
, node
) {
832 struct dentry
*dentry
;
834 inode
= ilookup(info
->sb
, kn
->ino
);
838 dentry
= d_find_any_alias(inode
);
840 fsnotify_parent(NULL
, dentry
, FS_MODIFY
);
841 fsnotify(inode
, FS_MODIFY
, inode
, FSNOTIFY_EVENT_INODE
,
849 mutex_unlock(&kernfs_mutex
);
855 * kernfs_notify - notify a kernfs file
856 * @kn: file to notify
858 * Notify @kn such that poll(2) on @kn wakes up. Maybe be called from any
861 void kernfs_notify(struct kernfs_node
*kn
)
863 static DECLARE_WORK(kernfs_notify_work
, kernfs_notify_workfn
);
866 if (WARN_ON(kernfs_type(kn
) != KERNFS_FILE
))
869 spin_lock_irqsave(&kernfs_notify_lock
, flags
);
870 if (!kn
->attr
.notify_next
) {
872 kn
->attr
.notify_next
= kernfs_notify_list
;
873 kernfs_notify_list
= kn
;
874 schedule_work(&kernfs_notify_work
);
876 spin_unlock_irqrestore(&kernfs_notify_lock
, flags
);
878 EXPORT_SYMBOL_GPL(kernfs_notify
);
880 const struct file_operations kernfs_file_fops
= {
881 .read
= kernfs_fop_read
,
882 .write
= kernfs_fop_write
,
883 .llseek
= generic_file_llseek
,
884 .mmap
= kernfs_fop_mmap
,
885 .open
= kernfs_fop_open
,
886 .release
= kernfs_fop_release
,
887 .poll
= kernfs_fop_poll
,
891 * __kernfs_create_file - kernfs internal function to create a file
892 * @parent: directory to create the file in
893 * @name: name of the file
894 * @mode: mode of the file
895 * @size: size of the file
896 * @ops: kernfs operations for the file
897 * @priv: private data for the file
898 * @ns: optional namespace tag of the file
899 * @name_is_static: don't copy file name
900 * @key: lockdep key for the file's active_ref, %NULL to disable lockdep
902 * Returns the created node on success, ERR_PTR() value on error.
904 struct kernfs_node
*__kernfs_create_file(struct kernfs_node
*parent
,
906 umode_t mode
, loff_t size
,
907 const struct kernfs_ops
*ops
,
908 void *priv
, const void *ns
,
910 struct lock_class_key
*key
)
912 struct kernfs_node
*kn
;
918 flags
|= KERNFS_STATIC_NAME
;
920 kn
= kernfs_new_node(parent
, name
, (mode
& S_IALLUGO
) | S_IFREG
, flags
);
922 return ERR_PTR(-ENOMEM
);
925 kn
->attr
.size
= size
;
929 #ifdef CONFIG_DEBUG_LOCK_ALLOC
931 lockdep_init_map(&kn
->dep_map
, "s_active", key
, 0);
932 kn
->flags
|= KERNFS_LOCKDEP
;
937 * kn->attr.ops is accesible only while holding active ref. We
938 * need to know whether some ops are implemented outside active
939 * ref. Cache their existence in flags.
942 kn
->flags
|= KERNFS_HAS_SEQ_SHOW
;
944 kn
->flags
|= KERNFS_HAS_MMAP
;
946 rc
= kernfs_add_one(kn
);