From: Andy Walls Date: Thu, 27 Jan 2011 05:10:42 +0000 (-0300) Subject: [media] lirc_zilog: Don't acquire the rx->buf_lock in the poll() function X-Git-Tag: firefly_0821_release~7613^2~1709^2~33 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=915e54733de4a36742ab78b4768750ce72662f85;p=firefly-linux-kernel-4.4.55.git [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: Andy Walls Signed-off-by: Jarod Wilson Signed-off-by: Mauro Carvalho Chehab --- diff --git a/drivers/staging/lirc/lirc_zilog.c b/drivers/staging/lirc/lirc_zilog.c index 720ef6739d0e..695c3df93ca8 100644 --- a/drivers/staging/lirc/lirc_zilog.c +++ b/drivers/staging/lirc/lirc_zilog.c @@ -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; }