* Re: [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte()
2018-04-04 17:53 [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte() Bart Van Assche
@ 2018-04-04 18:35 ` Douglas Gilbert
2018-04-04 19:54 ` Lee Duncan
` (3 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Douglas Gilbert @ 2018-04-04 18:35 UTC (permalink / raw)
To: Bart Van Assche, Martin K . Petersen, James E . J . Bottomley
Cc: linux-scsi, Hannes Reinecke, Damien Le Moal, Christoph Hellwig,
stable
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@wdc.com>
> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Douglas Gilbert <dgilbert@interlog.com>
> Cc: Damien Le Moal <damien.lemoal@wdc.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: stable@vger.kernel.org
> ---
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:
>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte()
2018-04-04 17:53 [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte() Bart Van Assche
2018-04-04 18:35 ` Douglas Gilbert
@ 2018-04-04 19:54 ` Lee Duncan
2018-04-05 2:28 ` Damien Le Moal
` (2 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Lee Duncan @ 2018-04-04 19:54 UTC (permalink / raw)
To: Bart Van Assche, Martin K . Petersen, James E . J . Bottomley
Cc: linux-scsi, Hannes Reinecke, Douglas Gilbert, Damien Le Moal,
Christoph Hellwig, stable
On 04/04/2018 10:53 AM, 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@wdc.com>
> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Douglas Gilbert <dgilbert@interlog.com>
> Cc: Damien Le Moal <damien.lemoal@wdc.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: stable@vger.kernel.org
> ---
>
> 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:
>
Reviewed-by: Lee Duncan <lduncan@suse.com>
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte()
2018-04-04 17:53 [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte() Bart Van Assche
2018-04-04 18:35 ` Douglas Gilbert
2018-04-04 19:54 ` Lee Duncan
@ 2018-04-05 2:28 ` Damien Le Moal
2018-04-05 6:43 ` Hannes Reinecke
2018-04-05 8:48 ` Christoph Hellwig
4 siblings, 0 replies; 8+ messages in thread
From: Damien Le Moal @ 2018-04-05 2:28 UTC (permalink / raw)
To: jejb@linux.vnet.ibm.com, Bart Van Assche,
martin.petersen@oracle.com
Cc: linux-scsi@vger.kernel.org, hch@lst.de, dgilbert@interlog.com,
hare@suse.com, stable@vger.kernel.org
On Wed, 2018-04-04 at 10:53 -0700, 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@wdc.com>
> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Douglas Gilbert <dgilbert@interlog.com>
> Cc: Damien Le Moal <damien.lemoal@wdc.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: stable@vger.kernel.org
> ---
>
> 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;
This fixes the problem on my system.
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>
--
Damien Le Moal
Western Digital
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte()
2018-04-04 17:53 [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte() Bart Van Assche
@ 2018-04-05 6:43 ` Hannes Reinecke
2018-04-04 19:54 ` Lee Duncan
` (3 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Hannes Reinecke @ 2018-04-05 6:43 UTC (permalink / raw)
To: Bart Van Assche
Cc: James E . J . Bottomley, Martin K . Petersen, Douglas Gilbert,
Christoph Hellwig, linux-scsi, stable, Damien Le Moal
On Wed, 4 Apr 2018 10:53:55 -0700
"Bart Van Assche" <bart.vanassche@wdc.com> 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@wdc.com> Signed-off-by: Bart Van Assche
> <bart.vanassche@wdc.com> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Douglas Gilbert <dgilbert@interlog.com>
> Cc: Damien Le Moal <damien.lemoal@wdc.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: stable@vger.kernel.org
> ---
>
> 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:
And a further nit-pick: the function is called
__scsi_error_from_host_byte(), so it's only logical that it would only
check the host_byte().
What's wrong is the _usage_ here; after calling
__scsi_error_from_host_byte() we need to check if the _other_ bits of
the results are non-zero to end up with a valid result.
Hence I would advocate to either rename this function
(__scsi_error_from_result() ?) or evaluate the remaining bits outside
this function.
But I would advocate for the former; otherwise the same issue will crop
up again in the future.
Cheers,
Hannes
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte()
@ 2018-04-05 6:43 ` Hannes Reinecke
0 siblings, 0 replies; 8+ messages in thread
From: Hannes Reinecke @ 2018-04-05 6:43 UTC (permalink / raw)
To: Bart Van Assche
Cc: James E . J . Bottomley, Martin K . Petersen, Douglas Gilbert,
Christoph Hellwig, linux-scsi, stable, Damien Le Moal
On Wed, 4 Apr 2018 10:53:55 -0700
"Bart Van Assche" <bart.vanassche@wdc.com> 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@wdc.com> Signed-off-by: Bart Van Assche
> <bart.vanassche@wdc.com> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Douglas Gilbert <dgilbert@interlog.com>
> Cc: Damien Le Moal <damien.lemoal@wdc.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: stable@vger.kernel.org
> ---
>
> 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:
And a further nit-pick: the function is called
__scsi_error_from_host_byte(), so it's only logical that it would only
check the host_byte().
What's wrong is the _usage_ here; after calling
__scsi_error_from_host_byte() we need to check if the _other_ bits of
the results are non-zero to end up with a valid result.
Hence I would advocate to either rename this function
(__scsi_error_from_result() ?) or evaluate the remaining bits outside
this function.
But I would advocate for the former; otherwise the same issue will crop
up again in the future.
Cheers,
Hannes
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte()
2018-04-05 6:43 ` Hannes Reinecke
(?)
@ 2018-04-05 8:50 ` Christoph Hellwig
-1 siblings, 0 replies; 8+ messages in thread
From: Christoph Hellwig @ 2018-04-05 8:50 UTC (permalink / raw)
To: Hannes Reinecke
Cc: Bart Van Assche, James E . J . Bottomley, Martin K . Petersen,
Douglas Gilbert, Christoph Hellwig, linux-scsi, stable,
Damien Le Moal
On Thu, Apr 05, 2018 at 08:43:18AM +0200, Hannes Reinecke wrote:
> And a further nit-pick: the function is called
> __scsi_error_from_host_byte(), so it's only logical that it would only
> check the host_byte().
> What's wrong is the _usage_ here; after calling
> __scsi_error_from_host_byte() we need to check if the _other_ bits of
> the results are non-zero to end up with a valid result.
>
> Hence I would advocate to either rename this function
> (__scsi_error_from_result() ?) or evaluate the remaining bits outside
> this function.
>
> But I would advocate for the former; otherwise the same issue will crop
> up again in the future.
Please also drop the pointless double underscore prefix while at it,
otherwise fully agreed.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte()
2018-04-04 17:53 [PATCH v2] Fix DID_OK handling in __scsi_error_from_host_byte() Bart Van Assche
` (3 preceding siblings ...)
2018-04-05 6:43 ` Hannes Reinecke
@ 2018-04-05 8:48 ` Christoph Hellwig
4 siblings, 0 replies; 8+ messages in thread
From: Christoph Hellwig @ 2018-04-05 8:48 UTC (permalink / raw)
To: Bart Van Assche
Cc: Martin K . Petersen, James E . J . Bottomley, linux-scsi,
Hannes Reinecke, Douglas Gilbert, Damien Le Moal,
Christoph Hellwig, stable
On Wed, Apr 04, 2018 at 10:53:55AM -0700, Bart Van Assche wrote:
> + /*
> + * 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;
How about an readable version of the statement above?
if (scsi_status_is_good(result) && (result & ~0xff))
return BLK_STS_OK;
return BLK_STS_IOERR;
^ permalink raw reply [flat|nested] 8+ messages in thread