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

[Luis Henriques]

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-3.5.y-queue branch of the 3.5.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-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From a4adb0528e946d44e18c5fe410c3a58749412117 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: Luis Henriques <luis.henriques 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 1041cb8..40f528b 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -574,7 +574,9 @@ 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