Re: [PATCH v2 01/10] mailbox: Support blocking transfers in atomic context

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Mon, Nov 12, 2018 at 9:18 AM Thierry Reding <thierry.reding@xxxxxxxxx> wrote:
>
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> The mailbox framework supports blocking transfers via completions for
> clients that can sleep. In order to support blocking transfers in cases
> where the transmission is not permitted to sleep, add a new ->flush()
> callback that controller drivers can implement to busy loop until the
> transmission has been completed. This will automatically be called when
> available and interrupts are disabled for clients that request blocking
> transfers.
>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
>  drivers/mailbox/mailbox.c          | 8 ++++++++
>  include/linux/mailbox_controller.h | 4 ++++
>  2 files changed, 12 insertions(+)
>
> diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
> index 674b35f402f5..0eaf21259874 100644
> --- a/drivers/mailbox/mailbox.c
> +++ b/drivers/mailbox/mailbox.c
> @@ -267,6 +267,14 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg)
>                 unsigned long wait;
>                 int ret;
>
> +               if (irqs_disabled() && chan->mbox->ops->flush) {
> +                       ret = chan->mbox->ops->flush(chan, chan->cl->tx_tout);
> +                       if (ret < 0)
> +                               tx_tick(chan, ret);
> +
> +                       return ret;
> +               }
> +
This is hacky. I think we can do without busy waiting in atomic
context. You could queue locally while in atomic context and then
transfer in blocking mode. I don't think we should worry about the
'throughput' as there already is no h/w rate control even with
busy-waiting.

Thanks.



[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux PPP]     [Linux FS]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Linmodem]     [Device Mapper]     [Linux Kernel for ARM]

  Powered by Linux