SIGIO-driven I/O with inotify queues
Add SIGIO-driven I/O for descriptors returned by inotify_init(). The thing
may be enabled by convenient fcntl (fd, F_SETFL, O_ASYNC) call.
Signed-off-by: Dmitry Antipov <antipov@dev.rtsoft.ru>
Cc: Robert Love <rlove@google.com>
Cc: John McCutchan <ttb@tentacle.dhs.org>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/inotify_user.c b/fs/inotify_user.c
index c509a81..a336c97 100644
--- a/fs/inotify_user.c
+++ b/fs/inotify_user.c
@@ -79,6 +79,7 @@
atomic_t count; /* reference count */
struct user_struct *user; /* user who opened this dev */
struct inotify_handle *ih; /* inotify handle */
+ struct fasync_struct *fa; /* async notification */
unsigned int queue_size; /* size of the queue (bytes) */
unsigned int event_count; /* number of pending events */
unsigned int max_events; /* maximum number of events */
@@ -315,6 +316,7 @@
dev->queue_size += sizeof(struct inotify_event) + kevent->event.len;
list_add_tail(&kevent->list, &dev->events);
wake_up_interruptible(&dev->wq);
+ kill_fasync(&dev->fa, SIGIO, POLL_IN);
out:
mutex_unlock(&dev->ev_mutex);
@@ -503,6 +505,13 @@
return ret;
}
+static int inotify_fasync(int fd, struct file *file, int on)
+{
+ struct inotify_device *dev = file->private_data;
+
+ return fasync_helper(fd, file, on, &dev->fa) >= 0 ? 0 : -EIO;
+}
+
static int inotify_release(struct inode *ignored, struct file *file)
{
struct inotify_device *dev = file->private_data;
@@ -515,6 +524,9 @@
inotify_dev_event_dequeue(dev);
mutex_unlock(&dev->ev_mutex);
+ if (file->f_flags & FASYNC)
+ inotify_fasync(-1, file, 0);
+
/* free this device: the put matching the get in inotify_init() */
put_inotify_dev(dev);
@@ -543,6 +555,7 @@
static const struct file_operations inotify_fops = {
.poll = inotify_poll,
.read = inotify_read,
+ .fasync = inotify_fasync,
.release = inotify_release,
.unlocked_ioctl = inotify_ioctl,
.compat_ioctl = inotify_ioctl,
@@ -590,6 +603,7 @@
goto out_free_dev;
}
dev->ih = ih;
+ dev->fa = NULL;
filp->f_op = &inotify_fops;
filp->f_path.mnt = mntget(inotify_mnt);