Commit-ID:  1b9f23727abb92c5e58f139e7d180befcaa06fe0
Gitweb:     http://git.kernel.org/tip/1b9f23727abb92c5e58f139e7d180befcaa06fe0
Author:     Richard Cochran <richardcoch...@gmail.com>
AuthorDate: Tue, 22 Dec 2015 22:19:58 +0100
Committer:  Thomas Gleixner <t...@linutronix.de>
CommitDate: Tue, 29 Dec 2015 11:33:06 +0100

posix-clock: Fix return code on the poll method's error path

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.

Reported-by: Markus Elfring <elfr...@users.sourceforge.net>
igned-off-by: Richard Cochran <richardcoch...@gmail.com>
Cc: John Stultz <john.stu...@linaro.org>
Cc: Julia Lawall <julia.law...@lip6.fr>
Link: 
http://lkml.kernel.org/r/1450819198-17420-1-git-send-email-richardcoch...@gmail.com
Cc: sta...@vger.kernel.org
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
---
 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);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to