[Linaro-acpi] [PATCH] Mailbox: Complete wait event only if Tx was successful
sudeep.holla at arm.com
Fri Dec 12 00:43:01 PST 2014
On Thursday 11 December 2014 01:46 AM, Ashwin Chaugule wrote:
> If a wait_for_completion_timeout() call returns due to a timeout,
> the mbox code can still call complete() after returning from the wait.
> This can cause subsequent transmissions on a channel to fail, since
> the wait_for_completion_timeout() sees the completion variable
> is !=0, caused by the erroneous complete() call, and immediately
> returns without waiting for the time as expected by the client.
> Fix this by calling complete() only if the TX was successful.
> Signed-off-by: Ashwin Chaugule <ashwin.chaugule at linaro.org>
> drivers/mailbox/mailbox.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
> index 17e9e4a..4acaddb 100644
> --- a/drivers/mailbox/mailbox.c
> +++ b/drivers/mailbox/mailbox.c
> @@ -101,7 +101,7 @@ static void tx_tick(struct mbox_chan *chan, int r)
> if (mssg && chan->cl->tx_done)
> chan->cl->tx_done(chan->cl, mssg, r);
> - if (chan->cl->tx_block)
> + if ((!r) && chan->cl->tx_block)
Just curious to check if there's another possible race which is
a different issue.
Suppose the timer fired and indicated that the Tx is complete, then
it tries to execute complete while the wait_for_completion_timeout timed
out. Does that make sense ?
So if yes, how about adding !completion_done(..) to the check while you
are at this ?
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