44  * pending queue is implemented as a singly linked list of kernfs_nodes.
94 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_stop_active()  local
95 	const struct kernfs_ops *ops = kernfs_ops(of->kn);  in kernfs_seq_stop_active()
99 	kernfs_put_active(of->kn);  in kernfs_seq_stop_active()
104 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_start()  local
108 	 * @of->mutex nests outside active ref and is primarily to ensure that  in kernfs_seq_start()
111 	mutex_lock(&of->mutex);  in kernfs_seq_start()
112 	if (!kernfs_get_active(of->kn))  in kernfs_seq_start()
115 	ops = kernfs_ops(of->kn);  in kernfs_seq_start()
133 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_next()  local
134 	const struct kernfs_ops *ops = kernfs_ops(of->kn);  in kernfs_seq_next()
154 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_stop()  local
158 	mutex_unlock(&of->mutex);  in kernfs_seq_stop()
163 	struct kernfs_open_file *of = sf->private;  in kernfs_seq_show()  local
165 	of->event = atomic_read(&of->kn->attr.open->event);  in kernfs_seq_show()
167 	return of->kn->attr.ops->seq_show(sf, v);  in kernfs_seq_show()
183 static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of,  in kernfs_file_direct_read()  argument
191 	buf = of->prealloc_buf;  in kernfs_file_direct_read()
193 		mutex_lock(&of->prealloc_mutex);  in kernfs_file_direct_read()
200 	 * @of->mutex nests outside active ref and is used both to ensure that  in kernfs_file_direct_read()
203 	mutex_lock(&of->mutex);  in kernfs_file_direct_read()
204 	if (!kernfs_get_active(of->kn)) {  in kernfs_file_direct_read()
206 		mutex_unlock(&of->mutex);  in kernfs_file_direct_read()
210 	of->event = atomic_read(&of->kn->attr.open->event);  in kernfs_file_direct_read()
211 	ops = kernfs_ops(of->kn);  in kernfs_file_direct_read()
213 		len = ops->read(of, buf, len, *ppos);  in kernfs_file_direct_read()
217 	kernfs_put_active(of->kn);  in kernfs_file_direct_read()
218 	mutex_unlock(&of->mutex);  in kernfs_file_direct_read()
231 	if (buf == of->prealloc_buf)  in kernfs_file_direct_read()
232 		mutex_unlock(&of->prealloc_mutex);  in kernfs_file_direct_read()
242  * @count: number of bytes
248 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_fop_read()  local
250 	if (of->kn->flags & KERNFS_HAS_SEQ_SHOW)  in kernfs_fop_read()
253 		return kernfs_file_direct_read(of, user_buf, count, ppos);  in kernfs_fop_read()
260  * @count: number of bytes
275 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_fop_write()  local
280 	if (of->atomic_write_len) {  in kernfs_fop_write()
282 		if (len > of->atomic_write_len)  in kernfs_fop_write()
288 	buf = of->prealloc_buf;  in kernfs_fop_write()
290 		mutex_lock(&of->prealloc_mutex);  in kernfs_fop_write()
303 	 * @of->mutex nests outside active ref and is used both to ensure that  in kernfs_fop_write()
306 	mutex_lock(&of->mutex);  in kernfs_fop_write()
307 	if (!kernfs_get_active(of->kn)) {  in kernfs_fop_write()
308 		mutex_unlock(&of->mutex);  in kernfs_fop_write()
313 	ops = kernfs_ops(of->kn);  in kernfs_fop_write()
315 		len = ops->write(of, buf, len, *ppos);  in kernfs_fop_write()
319 	kernfs_put_active(of->kn);  in kernfs_fop_write()
320 	mutex_unlock(&of->mutex);  in kernfs_fop_write()
326 	if (buf == of->prealloc_buf)  in kernfs_fop_write()
327 		mutex_unlock(&of->prealloc_mutex);  in kernfs_fop_write()
336 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_open()  local
338 	if (!of->vm_ops)  in kernfs_vma_open()
341 	if (!kernfs_get_active(of->kn))  in kernfs_vma_open()
344 	if (of->vm_ops->open)  in kernfs_vma_open()
345 		of->vm_ops->open(vma);  in kernfs_vma_open()
347 	kernfs_put_active(of->kn);  in kernfs_vma_open()
353 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_fault()  local
356 	if (!of->vm_ops)  in kernfs_vma_fault()
359 	if (!kernfs_get_active(of->kn))  in kernfs_vma_fault()
363 	if (of->vm_ops->fault)  in kernfs_vma_fault()
364 		ret = of->vm_ops->fault(vmf);  in kernfs_vma_fault()
366 	kernfs_put_active(of->kn);  in kernfs_vma_fault()
373 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_page_mkwrite()  local
376 	if (!of->vm_ops)  in kernfs_vma_page_mkwrite()
379 	if (!kernfs_get_active(of->kn))  in kernfs_vma_page_mkwrite()
383 	if (of->vm_ops->page_mkwrite)  in kernfs_vma_page_mkwrite()
384 		ret = of->vm_ops->page_mkwrite(vmf);  in kernfs_vma_page_mkwrite()
388 	kernfs_put_active(of->kn);  in kernfs_vma_page_mkwrite()
396 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_access()  local
399 	if (!of->vm_ops)  in kernfs_vma_access()
402 	if (!kernfs_get_active(of->kn))  in kernfs_vma_access()
406 	if (of->vm_ops->access)  in kernfs_vma_access()
407 		ret = of->vm_ops->access(vma, addr, buf, len, write);  in kernfs_vma_access()
409 	kernfs_put_active(of->kn);  in kernfs_vma_access()
418 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_set_policy()  local
421 	if (!of->vm_ops)  in kernfs_vma_set_policy()
424 	if (!kernfs_get_active(of->kn))  in kernfs_vma_set_policy()
428 	if (of->vm_ops->set_policy)  in kernfs_vma_set_policy()
429 		ret = of->vm_ops->set_policy(vma, new);  in kernfs_vma_set_policy()
431 	kernfs_put_active(of->kn);  in kernfs_vma_set_policy()
439 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_vma_get_policy()  local
442 	if (!of->vm_ops)  in kernfs_vma_get_policy()
445 	if (!kernfs_get_active(of->kn))  in kernfs_vma_get_policy()
449 	if (of->vm_ops->get_policy)  in kernfs_vma_get_policy()
450 		pol = of->vm_ops->get_policy(vma, addr);  in kernfs_vma_get_policy()
452 	kernfs_put_active(of->kn);  in kernfs_vma_get_policy()
471 	struct kernfs_open_file *of = kernfs_of(file);  in kernfs_fop_mmap()  local
476 	 * mmap path and of->mutex are prone to triggering spurious lockdep  in kernfs_fop_mmap()
479 	 * without grabbing @of->mutex by testing HAS_MMAP flag.  See the  in kernfs_fop_mmap()
482 	if (!(of->kn->flags & KERNFS_HAS_MMAP))  in kernfs_fop_mmap()
485 	mutex_lock(&of->mutex);  in kernfs_fop_mmap()
488 	if (!kernfs_get_active(of->kn))  in kernfs_fop_mmap()
491 	ops = kernfs_ops(of->kn);  in kernfs_fop_mmap()
492 	rc = ops->mmap(of, vma);  in kernfs_fop_mmap()
497 	 * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()  in kernfs_fop_mmap()
498 	 * to satisfy versions of X which crash if the mmap fails: that  in kernfs_fop_mmap()
505 	if (of->mmapped && of->vm_ops != vma->vm_ops)  in kernfs_fop_mmap()
517 	of->mmapped = true;  in kernfs_fop_mmap()
518 	of->vm_ops = vma->vm_ops;  in kernfs_fop_mmap()
521 	kernfs_put_active(of->kn);  in kernfs_fop_mmap()
523 	mutex_unlock(&of->mutex);  in kernfs_fop_mmap()
531  *	@of: kernfs_open_file for this instance of open
534  *	create one.  @of is chained to the files list.
543 				struct kernfs_open_file *of)  in kernfs_get_open_node()  argument
559 		list_add_tail(&of->list, &on->files);  in kernfs_get_open_node()
585  *	@of: associated kernfs_open_file
587  *	Put @kn->attr.open and unlink @of from the files list.  If
594 				 struct kernfs_open_file *of)  in kernfs_put_open_node()  argument
602 	if (of)  in kernfs_put_open_node()
603 		list_del(&of->list);  in kernfs_put_open_node()
621 	struct kernfs_open_file *of;  in kernfs_fop_open()  local
647 	of = kzalloc(sizeof(struct kernfs_open_file), GFP_KERNEL);  in kernfs_fop_open()
648 	if (!of)  in kernfs_fop_open()
653 	 * @of->mutex for files which implement mmap.  This is a rather  in kernfs_fop_open()
655 	 * mm->mmap_lock - mmap nests @of->mutex under mm->mmap_lock and  in kernfs_fop_open()
657 	 * which mm->mmap_lock nests, while holding @of->mutex.  As each  in kernfs_fop_open()
663 	 * Both paths of the branch look the same.  They're supposed to  in kernfs_fop_open()
664 	 * look that way and give @of->mutex different static lockdep keys.  in kernfs_fop_open()
667 		mutex_init(&of->mutex);  in kernfs_fop_open()
669 		mutex_init(&of->mutex);  in kernfs_fop_open()
671 	of->kn = kn;  in kernfs_fop_open()
672 	of->file = file;  in kernfs_fop_open()
678 	of->atomic_write_len = ops->atomic_write_len;  in kernfs_fop_open()
689 		int len = of->atomic_write_len ?: PAGE_SIZE;  in kernfs_fop_open()
690 		of->prealloc_buf = kmalloc(len + 1, GFP_KERNEL);  in kernfs_fop_open()
692 		if (!of->prealloc_buf)  in kernfs_fop_open()
694 		mutex_init(&of->prealloc_mutex);  in kernfs_fop_open()
709 	of->seq_file = file->private_data;  in kernfs_fop_open()
710 	of->seq_file->private = of;  in kernfs_fop_open()
717 	error = kernfs_get_open_node(kn, of);  in kernfs_fop_open()
722 		/* nobody has access to @of yet, skip @of->mutex */  in kernfs_fop_open()
723 		error = ops->open(of);  in kernfs_fop_open()
733 	kernfs_put_open_node(kn, of);  in kernfs_fop_open()
737 	kfree(of->prealloc_buf);  in kernfs_fop_open()
738 	kfree(of);  in kernfs_fop_open()
746 				struct kernfs_open_file *of)  in kernfs_release_file()  argument
749 	 * @of is guaranteed to have no other file operations in flight and  in kernfs_release_file()
751 	 * @kernfs_open_file_mutex is enough.  @of->mutex can't be used  in kernfs_release_file()
757 	if (!of->released) {  in kernfs_release_file()
763 		kn->attr.ops->release(of);  in kernfs_release_file()
764 		of->released = true;  in kernfs_release_file()
771 	struct kernfs_open_file *of = kernfs_of(filp);  in kernfs_fop_release()  local
775 		kernfs_release_file(kn, of);  in kernfs_fop_release()
779 	kernfs_put_open_node(kn, of);  in kernfs_fop_release()
781 	kfree(of->prealloc_buf);  in kernfs_fop_release()
782 	kfree(of);  in kernfs_fop_release()
790 	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()
812 			kernfs_release_file(kn, of);  in kernfs_drain_open_files()
834 __poll_t kernfs_generic_poll(struct kernfs_open_file *of, poll_table *wait)  in kernfs_generic_poll()  argument
836 	struct kernfs_node *kn = kernfs_dentry_node(of->file->f_path.dentry);  in kernfs_generic_poll()
839 	poll_wait(of->file, &on->poll, wait);  in kernfs_generic_poll()
841 	if (of->event != atomic_read(&on->event))  in kernfs_generic_poll()
849 	struct kernfs_open_file *of = kernfs_of(filp);  in kernfs_fop_poll()  local
857 		ret = kn->attr.ops->poll(of, wait);  in kernfs_fop_poll()
859 		ret = kernfs_generic_poll(of, wait);  in kernfs_fop_poll()
976  * @name: name of the file
977  * @mode: mode of the file
978  * @uid: uid of the file
979  * @gid: gid of the file
980  * @size: size of the file
983  * @ns: optional namespace tag of the file