openwrt/target/linux/brcm2708/patches-3.10/0168-spidev-fix-hang-when-transfer_one_message-fails.patch

From b68b4448dc37e5fd510f1bb9bbd62722ad497f41 Mon Sep 17 00:00:00 2001
From: Daniel Santos <daniel.santos@pobox.com>
Date: Sun, 5 Jan 2014 17:39:26 -0600
Subject: [PATCH 168/174] 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@pobox.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/spi/spi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -584,7 +584,9 @@ static void spi_pump_messages(struct kth
 	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;
 	}
 }