On 2018-04-04 01:53 PM, Bart Van Assche wrote:
Commit e39a97353e53 modified __scsi_error_from_host_byte() such
that that function translates DID_OK into BLK_STS_OK. However,
the description of that commit is wrong: it mentions that commit
2a842acab109 introduced a bug in __scsi_error_from_host_byte()
although that commit did not change the behavior of that function.
Additionally, commit e39a97353e53 introduced a severe bug: it causes
commands that fail with hostbyte=DID_OK and driverbyte=DRIVER_SENSE
to be completed with BLK_STS_OK. Fix __scsi_error_from_host_byte()
by only translating good status values into BLK_STS_OK.
Fixes: e39a97353e53 ("scsi: core: return BLK_STS_OK for DID_OK in __scsi_error_from_host_byte()")
Reported-by: Damien Le Moal <damien.lemoal@xxxxxxx>
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Reviewed-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: Damien Le Moal <damien.lemoal@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
There is some urgency here as the faulty patch is in lk 4.16.0
release.
My patch was prepared independently of seeing this one. Both
do the job (mine has a redundant status_byte(result) in the
conditional). And the function name is now completely misleading
but due to the urgency, that can wait for another day.
Changes compared to v1:
- Modified __scsi_error_from_host_byte() such that it again returns
BLK_STS_OK for CONDITION MET and other result codes that represent
success.
drivers/scsi/scsi_lib.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 74a39db57d49..1496b34af409 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -736,7 +736,13 @@ static blk_status_t __scsi_error_from_host_byte(struct scsi_cmnd *cmd,
{
switch (host_byte(result)) {
case DID_OK:
- return BLK_STS_OK;
+ /*
+ * Also check the other bytes than the status byte in result
+ * to handle the case when a SCSI LLD sets result to
+ * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION.
+ */
+ return scsi_status_is_good(result) && (result & ~0xff) == 0 ?
+ BLK_STS_OK : BLK_STS_IOERR;
case DID_TRANSPORT_FAILFAST:
return BLK_STS_TRANSPORT;
case DID_TARGET_FAILURE:
