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Commit 915e5473 authored by Andy Walls's avatar Andy Walls Committed by Mauro Carvalho Chehab
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[media] lirc_zilog: Don't acquire the rx->buf_lock in the poll() function 



There is no need to take the rx->buf_lock in the the poll() function
as all the underling calls made on objects in the rx->buf lirc_buffer object
are protected by spinlocks.

Corrected a bad error return value in poll(): return POLLERR instead
of -ENODEV.

Added some comments to poll() for when, in the future, I forget what
poll() and poll_wait() are supposed to do.

[Jarod: minor debug spew fix]

Signed-off-by: default avatarAndy Walls <awalls@md.metrocast.net>
Signed-off-by: default avatarJarod Wilson <jarod@redhat.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 9a55a2b3

drivers/staging/lirc/lirc_zilog.c

+14 −7
Original line number Diff line number Diff line
@@ -985,19 +985,26 @@ static unsigned int poll(struct file *filep, poll_table *wait) 
	unsigned int ret;



	dprintk("poll called\n");

	if (rx == NULL)

		return -ENODEV;



	mutex_lock(&rx->buf_lock);

	if (rx == NULL) {

		/*

		 * Revisit this, if our poll function ever reports writeable

		 * status for Tx

		 */

		dprintk("poll result = POLLERR\n");

		return POLLERR;

	}



	/*

	 * Add our lirc_buffer's wait_queue to the poll_table. A wake up on

	 * that buffer's wait queue indicates we may have a new poll status.

	 */

	poll_wait(filep, &rx->buf.wait_poll, wait);



	dprintk("poll result = %s\n",

		lirc_buffer_empty(&rx->buf) ? "0" : "POLLIN|POLLRDNORM");



	/* Indicate what ops could happen immediately without blocking */

	ret = lirc_buffer_empty(&rx->buf) ? 0 : (POLLIN|POLLRDNORM);



	mutex_unlock(&rx->buf_lock);

	dprintk("poll result = %s\n", ret ? "POLLIN|POLLRDNORM" : "none");

	return ret;

}