lkml.org 
[lkml]   [2017]   [Mar]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH] mailbox: always wait in mbox_send_message for blocking tx mode
Hi Sudeep,

thanks for sending this patch.

On Mon, Mar 20, 2017 at 03:40:10PM +0000, Sudeep Holla wrote:
> There exists a race when msg_submit return immediately as there was an
> active request being processed which may have completed just before it's
> checked again in mbox_send_message. This will result in return to the
> caller without waiting in mbox_send_message even when it's blocking Tx.
>
> This patch fixes the issue by making use of non-negative token returned
> by add_to_rbuf to check if the request was queued and block always if
> so in blocking Tx mode.
>
> Fixes: 2b6d83e2b8b7 ("mailbox: Introduce framework for mailbox")
> Cc: Jassi Brar <jassisinghbrar@gmail.com>
> Reported-by: Alexey Klimov <alexey.klimov@arm.com>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
> 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 4671f8a12872..d5895791ab5d 100644
> --- a/drivers/mailbox/mailbox.c
> +++ b/drivers/mailbox/mailbox.c
> @@ -260,7 +260,7 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg)
>
> msg_submit(chan);
>
> - if (chan->cl->tx_block && chan->active_req) {
> + if (chan->cl->tx_block && t >= 0) {

What do you think about removing t>=0 at all?
If add_to_rbuf() above returns negative number then we won't reach this point
in code at all and quit this function with error. If execution reaches this line then
we can say that t is definetely >= 0 and maybe it shouldn't be checked.


Best regards,
Alexey

\
 
 \ /
  Last update: 2017-03-20 19:47    [W:0.049 / U:12.636 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site