Re: [PATCH 3.5 36/88] spidev: fix hang when transfer_one_messagefails

From: Daniel Santos
Date: Fri Feb 07 2014 - 13:16:11 EST


On 02/07/2014 05:22 AM, Luis Henriques wrote:
3.5.7.30 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Daniel Santos <daniel.santos@xxxxxxxxx>

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@xxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
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;
}
}

This isn't a good patch and is reverted by a later patch. I'm not sure what the protocol for this is, but either skip this patch or include the one that reverts it.

Daniel

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