[PATCH AUTOSEL for 3.18 04/16] libata: drop WARN from protocol error in ata_sff_qc_issue()

[alexander.levin@verizon.com]

From: Tejun Heo <tj@kernel.org>

[ Upstream commit 0580b762a4d6b70817476b90042813f8573283fa ]

ata_sff_qc_issue() expects upper layers to never issue commands on a
command protocol that it doesn't implement.  While the assumption
holds fine with the usual IO path, nothing filters based on the
command protocol in the passthrough path (which was added later),
allowing the warning to be tripped with a passthrough command with the
right (well, wrong) protocol.

Failing with AC_ERR_SYSTEM is the right thing to do anyway.  Remove
the unnecessary WARN.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Link: http://lkml.kernel.org/r/CACT4Y+bXkvevNZU8uP6X0QVqsj6wNoUA_1exfTSOzc+SmUtMOA@mail.gmail.com
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
---
 drivers/ata/libata-sff.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 12d337754e4a..58b0a58a7f1d 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -1480,7 +1480,6 @@ unsigned int ata_sff_qc_issue(struct ata_queued_cmd *qc)
 		break;
 
 	default:
-		WARN_ON_ONCE(1);
 		return AC_ERR_SYSTEM;
 	}
 
-- 
2.11.0