[PATCH v2] libata: clear error mask of old error history

[Lin Ming <ming.m.lin@intel.com>]

The old error history was cleared in ata_ering_clear().
It only sets ATA_EFLAG_OLD_ER eflags, but the err_mask was not cleared.
So ata_ering_map() still iterates the old error history.

This causes problem, for example, wrong probe trials count were returned in
ata_eh_schedule_probe(), which in turn causes SATA link speed to be slowed down
to 1.5Gbps.

Reported-and-tested-by: Martin Mokrejs <mmokrejs@fold.natur.cuni.cz>
Reviewed-by: Grant Grundler <grundler@google.com>
Cc: stable <stable@vger.kernel.org> # 2.6.37+
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
---

v2:
- Add Grant's review
- CC stable

 drivers/ata/libata-eh.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index c61316e..4c6f49b 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -419,9 +419,10 @@ int ata_ering_map(struct ata_ering *ering,
 	return rc;
 }
 
-int ata_ering_clear_cb(struct ata_ering_entry *ent, void *void_arg)
+static int ata_ering_clear_cb(struct ata_ering_entry *ent, void *void_arg)
 {
 	ent->eflags |= ATA_EFLAG_OLD_ER;
+	ent->err_mask = 0;
 	return 0;
 }
 
-- 
1.7.2.5