Messages in this thread Patch in this message |  | | From | Richard Cochran <> | Subject | [PATCH] posix-clock: fix return code on the poll method's error path | Date | Tue, 22 Dec 2015 22:19:58 +0100 |
| |
The posix_clock_poll function is supposed to return a bit mask of POLLxxx values. However, in case the hardware has disappeared (due to hot plugging for example) this code returns -ENODEV in a futile attempt to throw an error at the file descriptor level. The kernel's file_operations interface does not accept such error codes from the poll method. Instead, this function aught to return POLLERR.
The value -ENODEV does, in fact, contain the POLLERR bit (and almost all the other POLLxxx bits as well), but only by chance. This patch fixes code to return a proper bit mask.
Credit goes to Markus Elfring for pointing out the suspicious signed/unsigned mismatch.
Signed-off-by: Richard Cochran <richardcochran@gmail.com> --- kernel/time/posix-clock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c index ce033c7..9cff0ab 100644 --- a/kernel/time/posix-clock.c +++ b/kernel/time/posix-clock.c @@ -69,10 +69,10 @@ static ssize_t posix_clock_read(struct file *fp, char __user *buf, static unsigned int posix_clock_poll(struct file *fp, poll_table *wait) { struct posix_clock *clk = get_posix_clock(fp); - int result = 0; + unsigned int result = 0; if (!clk) - return -ENODEV; + return POLLERR; if (clk->ops.poll) result = clk->ops.poll(clk, fp, wait); -- 2.1.4
|  |