[3.8.y.z extended stable] Patch "spidev: fix hang when transfer_one_message fails" has been added to staging queue

[Daniel Santos]

On 02/07/2014 03:36 PM, Kamal Mostafa wrote:
> This is a note to let you know that I have just added a patch titled
>
>      spidev: fix hang when transfer_one_message fails
>
> to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree
> which can be found at:
>
>   http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue
>
> This patch is scheduled to be released in version 3.8.13.18.
>
> If you, or anyone else, feels it should not be added to this tree, please
> reply to this email.
>
> For more information about the 3.8.y.z tree, see
> https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
>
> Thanks.
> -Kamal
>
> ------
>
> >From 58251f1ad6870f0478a17f0be0488af61e3df3f9 Mon Sep 17 00:00:00 2001
> From: Daniel Santos <daniel.santos at pobox.com>
> Date: Sun, 5 Jan 2014 17:39:26 -0600
> Subject: spidev: fix hang when transfer_one_message fails
>
> commit e120cc0dcf2880a4c5c0a6cb27b655600a1cfa1d upstream.
>
> This corrects a problem in spi_pump_messages() that leads to an spi
> message hanging forever when a call to transfer_one_message() fails.
> This failure occurs in my MCP2210 driver when the cs_change bit is set
> on the last transfer in a message, an operation which the hardware does
> not support.
>
> Rationale
> Since the transfer_one_message() returns an int, we must presume that it
> may fail.  If transfer_one_message() should never fail, it should return
> void.  Thus, calls to transfer_one_message() should properly manage a
> failure.
>
> Fixes: ffbbdd21329f3 (spi: create a message queueing infrastructure)
> Signed-off-by: Daniel Santos <daniel.santos at pobox.com>
> Signed-off-by: Mark Brown <broonie at linaro.org>
> Signed-off-by: Kamal Mostafa <kamal at canonical.com>
> ---
>   drivers/spi/spi.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 19ee901..3f178d0 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -585,7 +585,9 @@ static void spi_pump_messages(struct kthread_work *work)
>   	ret = master->transfer_one_message(master, master->cur_msg);
>   	if (ret) {
>   		dev_err(&master->dev,
> -			"failed to transfer one message from queue\n");
> +			"failed to transfer one message from queue: %d\n", ret);
> +		master->cur_msg->status = ret;
> +		spi_finalize_current_message(master);
>   		return;
>   	}
>   }
> --
> 1.8.3.2

Actually, please drop it. It's not a good patch and is reverted with 
another patch later.

Daniel