linux-kernel - Re: [PATCH 1/3] mailbox: always wait in mbox_send

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Message-ID: <CABb+yY3hgNYPO0Ksot5ZrPEEk5cOYhvbqE9jBQUPRF+dzaEtMQ@mail.gmail.com>
Date:   Tue, 28 Mar 2017 23:50:13 +0530
From:   Jassi Brar <jassisinghbrar@...il.com>
To:     Sudeep Holla <sudeep.holla@....com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Jassi Brar <jaswinder.singh@...aro.org>,
        Alexey Klimov <alexey.klimov@....com>
Subject: Re: [PATCH 1/3] mailbox: always wait in mbox_send_message for
 blocking Tx mode

Hi Sudeep,

On Tue, Mar 21, 2017 at 5:00 PM, Sudeep Holla <sudeep.holla@....com> 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 waiting for the completion always if Tx
> is in blocking mode.
>
> Fixes: 2b6d83e2b8b7 ("mailbox: Introduce framework for mailbox")
> Cc: Jassi Brar <jassisinghbrar@...il.com>
> Reported-by: Alexey Klimov <alexey.klimov@....com>
> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> ---
>  drivers/mailbox/mailbox.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Hi Jassi,
>
> Here are fixes for few issues we encountered when dealing with multiple
> requests on multiple channels simultaneously.
>
Thanks for finding the bug.

I see patch-1 tries to fix the bug.  Patch-2,3 try to fix the
ramifications of the bug
but they may change behaviour for some users. Do you face any issue even after
applying patch-1 ?

Thanks