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.
Signed-off-by: Andy Walls <awalls@xxxxxxxxxxxxxxxx>
---
drivers/staging/lirc/lirc_zilog.c | 21 ++++++++++++++-------
1 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/staging/lirc/lirc_zilog.c b/drivers/staging/lirc/lirc_zilog.c
index 720ef67..dfa6a42 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" : 0);
return ret;
}
--
1.7.2.1
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