From 915e54733de4a36742ab78b4768750ce72662f85 Mon Sep 17 00:00:00 2001 From: Andy Walls Date: Thu, 27 Jan 2011 02:10:42 -0300 Subject: [PATCH] [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 --- drivers/staging/lirc/lirc_zilog.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/staging/lirc/lirc_zilog.c b/drivers/staging/lirc/lirc_zilog.c index 720ef6739d0..695c3df93ca 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; } -- 2.46.0