33  * pending queue is implemented as a singly linked list of kernfs_nodes.
62  * of_on - Get the kernfs_open_node of the specified kernfs_open_file
63  * @of: target kernfs_open_file
65  * Return: the kernfs_open_node of the kernfs_open_file
67 static struct kernfs_open_node *of_on(struct kernfs_open_file *of)  in of_on()  argument
69 	return rcu_dereference_protected(of->kn->attr.open,  in of_on()
70 					 !list_empty(&of->list));  in of_on()
78  * Fetch and return ->attr.open of @kn when caller holds the
81  * Update of ->attr.open happens under kernfs_open_file_mutex_ptr(kn). So when
137 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_stop_active()  local
138 	const struct kernfs_ops *ops = kernfs_ops(of->kn);  in kernfs_seq_stop_active()
142 	kernfs_put_active(of->kn);  in kernfs_seq_stop_active()
147 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_start()  local
151 	 * @of->mutex nests outside active ref and is primarily to ensure that  in kernfs_seq_start()
154 	mutex_lock(&of->mutex);  in kernfs_seq_start()
155 	if (!kernfs_get_active(of->kn))  in kernfs_seq_start()
158 	ops = kernfs_ops(of->kn);  in kernfs_seq_start()
171 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_next()  local
172 	const struct kernfs_ops *ops = kernfs_ops(of->kn);  in kernfs_seq_next()
192 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_stop()  local
196 	mutex_unlock(&of->mutex);  in kernfs_seq_stop()
201 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_show()  local
203 	of->event = atomic_read(&of_on(of)->event);  in kernfs_seq_show()
205 	return of->kn->attr.ops->seq_show(sf, v);  in kernfs_seq_show()
223 	struct kernfs_open_file *of = kernfs_of(iocb->ki_filp);  in kernfs_file_read_iter()  local
228 	buf = of->prealloc_buf;  in kernfs_file_read_iter()
230 		mutex_lock(&of->prealloc_mutex);  in kernfs_file_read_iter()
237 	 * @of->mutex nests outside active ref and is used both to ensure that  in kernfs_file_read_iter()
240 	mutex_lock(&of->mutex);  in kernfs_file_read_iter()
241 	if (!kernfs_get_active(of->kn)) {  in kernfs_file_read_iter()
243 		mutex_unlock(&of->mutex);  in kernfs_file_read_iter()
247 	of->event = atomic_read(&of_on(of)->event);  in kernfs_file_read_iter()
249 	ops = kernfs_ops(of->kn);  in kernfs_file_read_iter()
251 		len = ops->read(of, buf, len, iocb->ki_pos);  in kernfs_file_read_iter()
255 	kernfs_put_active(of->kn);  in kernfs_file_read_iter()
256 	mutex_unlock(&of->mutex);  in kernfs_file_read_iter()
269 	if (buf == of->prealloc_buf)  in kernfs_file_read_iter()
270 		mutex_unlock(&of->prealloc_mutex);  in kernfs_file_read_iter()
295 	struct kernfs_open_file *of = kernfs_of(iocb->ki_filp);  in kernfs_fop_write_iter()  local
300 	if (of->atomic_write_len) {  in kernfs_fop_write_iter()
301 		if (len > of->atomic_write_len)  in kernfs_fop_write_iter()
307 	buf = of->prealloc_buf;  in kernfs_fop_write_iter()
309 		mutex_lock(&of->prealloc_mutex);  in kernfs_fop_write_iter()
322 	 * @of->mutex nests outside active ref and is used both to ensure that  in kernfs_fop_write_iter()
325 	mutex_lock(&of->mutex);  in kernfs_fop_write_iter()
326 	if (!kernfs_get_active(of->kn)) {  in kernfs_fop_write_iter()
327 		mutex_unlock(&of->mutex);  in kernfs_fop_write_iter()
332 	ops = kernfs_ops(of->kn);  in kernfs_fop_write_iter()
334 		len = ops->write(of, buf, len, iocb->ki_pos);  in kernfs_fop_write_iter()
338 	kernfs_put_active(of->kn);  in kernfs_fop_write_iter()
339 	mutex_unlock(&of->mutex);  in kernfs_fop_write_iter()
345 	if (buf == of->prealloc_buf)  in kernfs_fop_write_iter()
346 		mutex_unlock(&of->prealloc_mutex);  in kernfs_fop_write_iter()
355 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_open()  local
357 	if (!of->vm_ops)  in kernfs_vma_open()
360 	if (!kernfs_get_active(of->kn))  in kernfs_vma_open()
363 	if (of->vm_ops->open)  in kernfs_vma_open()
364 		of->vm_ops->open(vma);  in kernfs_vma_open()
366 	kernfs_put_active(of->kn);  in kernfs_vma_open()
372 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_fault()  local
375 	if (!of->vm_ops)  in kernfs_vma_fault()
378 	if (!kernfs_get_active(of->kn))  in kernfs_vma_fault()
382 	if (of->vm_ops->fault)  in kernfs_vma_fault()
383 		ret = of->vm_ops->fault(vmf);  in kernfs_vma_fault()
385 	kernfs_put_active(of->kn);  in kernfs_vma_fault()
392 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_page_mkwrite()  local
395 	if (!of->vm_ops)  in kernfs_vma_page_mkwrite()
398 	if (!kernfs_get_active(of->kn))  in kernfs_vma_page_mkwrite()
402 	if (of->vm_ops->page_mkwrite)  in kernfs_vma_page_mkwrite()
403 		ret = of->vm_ops->page_mkwrite(vmf);  in kernfs_vma_page_mkwrite()
407 	kernfs_put_active(of->kn);  in kernfs_vma_page_mkwrite()
415 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_access()  local
418 	if (!of->vm_ops)  in kernfs_vma_access()
421 	if (!kernfs_get_active(of->kn))  in kernfs_vma_access()
425 	if (of->vm_ops->access)  in kernfs_vma_access()
426 		ret = of->vm_ops->access(vma, addr, buf, len, write);  in kernfs_vma_access()
428 	kernfs_put_active(of->kn);  in kernfs_vma_access()
441 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_fop_mmap()  local
446 	 * mmap path and of->mutex are prone to triggering spurious lockdep  in kernfs_fop_mmap()
449 	 * without grabbing @of->mutex by testing HAS_MMAP flag.  See the  in kernfs_fop_mmap()
452 	if (!(of->kn->flags & KERNFS_HAS_MMAP))  in kernfs_fop_mmap()
455 	mutex_lock(&of->mutex);  in kernfs_fop_mmap()
458 	if (!kernfs_get_active(of->kn))  in kernfs_fop_mmap()
461 	ops = kernfs_ops(of->kn);  in kernfs_fop_mmap()
462 	rc = ops->mmap(of, vma);  in kernfs_fop_mmap()
467 	 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()  in kernfs_fop_mmap()
468 	 * to satisfy versions of X which crash if the mmap fails: that  in kernfs_fop_mmap()
475 	if (of->mmapped && of->vm_ops != vma->vm_ops)  in kernfs_fop_mmap()
486 	if (!of->mmapped) {  in kernfs_fop_mmap()
487 		of->mmapped = true;  in kernfs_fop_mmap()
488 		of_on(of)->nr_mmapped++;  in kernfs_fop_mmap()
489 		of->vm_ops = vma->vm_ops;  in kernfs_fop_mmap()
493 	kernfs_put_active(of->kn);  in kernfs_fop_mmap()
495 	mutex_unlock(&of->mutex);  in kernfs_fop_mmap()
503  *	@of: kernfs_open_file for this instance of open
506  *	create one.  @of is chained to the files list.
515 				struct kernfs_open_file *of)  in kernfs_get_open_node()  argument
536 	list_add_tail(&of->list, &on->files);  in kernfs_get_open_node()
545  *	kernfs_unlink_open_file - Unlink @of from @kn.
548  *	@of: associated kernfs_open_file
551  *	Unlink @of from list of @kn's associated open files. If list of
559 				    struct kernfs_open_file *of,  in kernfs_unlink_open_file()  argument
573 	if (of) {  in kernfs_unlink_open_file()
575 			WARN_ON_ONCE(of->released == open_failed);  in kernfs_unlink_open_file()
579 		if (of->mmapped)  in kernfs_unlink_open_file()
581 		list_del(&of->list);  in kernfs_unlink_open_file()
597 	struct kernfs_open_file *of;  in kernfs_fop_open()  local
623 	of = kzalloc(sizeof(struct kernfs_open_file), GFP_KERNEL);  in kernfs_fop_open()
624 	if (!of)  in kernfs_fop_open()
629 	 * @of->mutex for files which implement mmap.  This is a rather  in kernfs_fop_open()
631 	 * mm->mmap_lock - mmap nests @of->mutex under mm->mmap_lock and  in kernfs_fop_open()
633 	 * which mm->mmap_lock nests, while holding @of->mutex.  As each  in kernfs_fop_open()
642 	 * overlayfs from vfs helpers when sysfs is a lower layer of overalyfs.  in kernfs_fop_open()
645 	 * look that way and give @of->mutex different static lockdep keys.  in kernfs_fop_open()
648 		mutex_init(&of->mutex);  in kernfs_fop_open()
650 		mutex_init(&of->mutex);  in kernfs_fop_open()
652 		mutex_init(&of->mutex);  in kernfs_fop_open()
654 	of->kn = kn;  in kernfs_fop_open()
655 	of->file = file;  in kernfs_fop_open()
661 	of->atomic_write_len = ops->atomic_write_len;  in kernfs_fop_open()
672 		int len = of->atomic_write_len ?: PAGE_SIZE;  in kernfs_fop_open()
673 		of->prealloc_buf = kmalloc(len + 1, GFP_KERNEL);  in kernfs_fop_open()
675 		if (!of->prealloc_buf)  in kernfs_fop_open()
677 		mutex_init(&of->prealloc_mutex);  in kernfs_fop_open()
692 	of->seq_file = file->private_data;  in kernfs_fop_open()
693 	of->seq_file->private = of;  in kernfs_fop_open()
700 	error = kernfs_get_open_node(kn, of);  in kernfs_fop_open()
705 		/* nobody has access to @of yet, skip @of->mutex */  in kernfs_fop_open()
706 		error = ops->open(of);  in kernfs_fop_open()
716 	kernfs_unlink_open_file(kn, of, true);  in kernfs_fop_open()
720 	kfree(of->prealloc_buf);  in kernfs_fop_open()
721 	kfree(of);  in kernfs_fop_open()
729 				struct kernfs_open_file *of)  in kernfs_release_file()  argument
732 	 * @of is guaranteed to have no other file operations in flight and  in kernfs_release_file()
734 	 * @kernfs_open_file_mutex_ptr(kn) is enough. @of->mutex can't be used  in kernfs_release_file()
740 	if (!of->released) {  in kernfs_release_file()
746 		kn->attr.ops->release(of);  in kernfs_release_file()
747 		of->released = true;  in kernfs_release_file()
748 		of_on(of)->nr_to_release--;  in kernfs_release_file()
755 	struct kernfs_open_file *of = kernfs_of(filp);  in kernfs_fop_release()  local
761 		kernfs_release_file(kn, of);  in kernfs_fop_release()
765 	kernfs_unlink_open_file(kn, of, false);  in kernfs_fop_release()
767 	kfree(of->prealloc_buf);  in kernfs_fop_release()
768 	kfree(of);  in kernfs_fop_release()
795 	struct kernfs_open_file *of;  in kernfs_drain_open_files()  local
805 	list_for_each_entry(of, &on->files, list) {  in kernfs_drain_open_files()
806 		struct inode *inode = file_inode(of->file);  in kernfs_drain_open_files()
808 		if (of->mmapped) {  in kernfs_drain_open_files()
810 			of->mmapped = false;  in kernfs_drain_open_files()
815 			kernfs_release_file(kn, of);  in kernfs_drain_open_files()
836 __poll_t kernfs_generic_poll(struct kernfs_open_file *of, poll_table *wait)  in kernfs_generic_poll()  argument
838 	struct kernfs_open_node *on = of_on(of);  in kernfs_generic_poll()
840 	poll_wait(of->file, &on->poll, wait);  in kernfs_generic_poll()
842 	if (of->event != atomic_read(&on->event))  in kernfs_generic_poll()
850 	struct kernfs_open_file *of = kernfs_of(filp);  in kernfs_fop_poll()  local
858 		ret = kn->attr.ops->poll(of, wait);  in kernfs_fop_poll()
860 		ret = kernfs_generic_poll(of, wait);  in kernfs_fop_poll()
868 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_fop_llseek()  local
873 	 * @of->mutex nests outside active ref and is primarily to ensure that  in kernfs_fop_llseek()
876 	mutex_lock(&of->mutex);  in kernfs_fop_llseek()
877 	if (!kernfs_get_active(of->kn)) {  in kernfs_fop_llseek()
878 		mutex_unlock(&of->mutex);  in kernfs_fop_llseek()
882 	ops = kernfs_ops(of->kn);  in kernfs_fop_llseek()
884 		ret = ops->llseek(of, offset, whence);  in kernfs_fop_llseek()
888 	kernfs_put_active(of->kn);  in kernfs_fop_llseek()
889 	mutex_unlock(&of->mutex);  in kernfs_fop_llseek()
1008  * @name: name of the file
1009  * @mode: mode of the file
1010  * @uid: uid of the file
1011  * @gid: gid of the file
1012  * @size: size of the file
1015  * @ns: optional namespace tag of the file