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

[Kamal Mostafa]

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