[PATCH v10 00/33] scsi: Allow scsi_execute users to control retries

[PATCH v10 00/33] scsi: Allow scsi_execute users to control retries

[Mike Christie]

he following patches were made over Martin's 6.6 scsi-queue branch.
They allow scsi_execute_cmd users to control exactly which errors are
retried, so we can reduce the sense/sshd handling they have to do and
have it one place.

The patches allow scsi_execute_cmd users to pass in an array of failures
which they want retried/failed and also specify how many times they want
them retried. If we hit an error that the user did not specify then we drop
down to the default behavior. This allows us to remove almost all the
retry logic from scsi_execute_cmd users. We just have the special cases
where we want to retry with a difference size command or sleep between
retries.

v10:
- Drop "," after {}.
- Hopefully fix outlook issues.

v9:
- Drop spi_execute changes from [PATCH] scsi: spi: Fix sshdr use
- Change git commit message for sshdr use fixes to try and make it
more clear when we need to check and when we can check.

v8:
- Rebase.
- Saw the discussion about the possible bug where callers are
accessing the sshdr when it's not setup, so I added some patches
for that since I was going over the same code.

v7:
- Rebase against scsi_execute_cmd patchset.

v6:
- Fix kunit build when it's built as a module but scsi is not.
- Drop [PATCH 17/35] scsi: ufshcd: Convert to scsi_exec_req because
  that driver no longer uses scsi_execute.
- Convert ufshcd to use the scsi_failures struct because it now just does
  direct retries and does not do it's own deadline timing.
- Add back memset in read_capacity_16.
- Remove memset in get_sectorsize and replace with { } to init buf.

v5:
- Fix spelling (made sure I ran checkpatch strict)
- Drop SCMD_FAILURE_NONE
- Rename SCMD_FAILURE_ANY
- Fix media_not_present handling where it was being retried instead of
failed.
- Fix ILLEGAL_REQUEST handling in read_capacity_16 so it was not retried.
- Fix coding style, spelling and and naming convention in kunit and added
  more tests to handle cases like the media_not_present one where we want
  to force failures instead of retries.
- Drop cxlflash patch because it actually checked it's internal state before
  performing a retry which we currently do not support.

v4:
- Redefine cmd definitions if the cmd is touched.
- Fix up coding style issues.
- Use sam_status enum.
- Move failures initialization to scsi_initialize_rq
(also fixes KASAN error).
- Add kunit test.
- Add function comments.

v3:
- Use a for loop in scsi_check_passthrough
- Fix result handling/testing.
- Fix scsi_status_is_good handling.
- make __scsi_exec_req take a const arg
- Fix formatting in patch 24

v2:
- Rename scsi_prep_sense
- Change scsi_check_passthrough's loop and added some fixes
- Modified scsi_execute* so it uses a struct to pass in args

[PATCH v10 01/33] scsi: Add helper to prep sense during error handling

[Mike Christie]

This breaks out the sense prep so it can be used in helper that will be
added in this patchset for passthrough commands.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin Wilck <mwilck@suse.com>
---
 drivers/scsi/scsi_error.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index c67cdcdc3ba8..7c3eccbdd39f 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -523,6 +523,23 @@ static inline void set_scsi_ml_byte(struct scsi_cmnd *cmd, u8 status)
 	cmd->result = (cmd->result & 0xffff00ff) | (status << 8);
 }
 
+static enum scsi_disposition
+scsi_start_sense_processing(struct scsi_cmnd *scmd,
+			    struct scsi_sense_hdr *sshdr)
+{
+	struct scsi_device *sdev = scmd->device;
+
+	if (!scsi_command_normalize_sense(scmd, sshdr))
+		return FAILED;  /* no valid sense data */
+
+	scsi_report_sense(sdev, sshdr);
+
+	if (scsi_sense_is_deferred(sshdr))
+		return NEEDS_RETRY;
+
+	return SUCCESS;
+}
+
 /**
  * scsi_check_sense - Examine scsi cmd sense
  * @scmd:	Cmd to have sense checked.
@@ -539,14 +556,11 @@ enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
 	struct request *req = scsi_cmd_to_rq(scmd);
 	struct scsi_device *sdev = scmd->device;
 	struct scsi_sense_hdr sshdr;
+	enum scsi_disposition ret;
 
-	if (! scsi_command_normalize_sense(scmd, &sshdr))
-		return FAILED;	/* no valid sense data */
-
-	scsi_report_sense(sdev, &sshdr);
-
-	if (scsi_sense_is_deferred(&sshdr))
-		return NEEDS_RETRY;
+	ret = scsi_start_sense_processing(scmd, &sshdr);
+	if (ret != SUCCESS)
+		return ret;
 
 	if (sdev->handler && sdev->handler->check_sense) {
 		enum scsi_disposition rc;
-- 
2.34.1

Re: [PATCH v10 01/33] scsi: Add helper to prep sense during error handling

[John Garry]

On 14/07/2023 22:33, Mike Christie wrote:
> This breaks out the sense prep so it can be used in helper that will be
> added in this patchset for passthrough commands.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Bart Van Assche<bvanassche@acm.org>
> Reviewed-by: Christoph Hellwig<hch@lst.de>
> Reviewed-by: Martin Wilck<mwilck@suse.com>

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 02/33] scsi: Allow passthrough to override what errors to retry

[Mike Christie]

For passthrough, we don't retry any error we get a check condition for.
This results in a lot of callers driving their own retries for those types
of errors and retrying all errors, and there has been a request to retry
specific host byte errors.

This adds the core code to allow passthrough users to specify what errors
they want scsi-ml to retry for them. We can then convert users to drop
their sense parsing and retry handling.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/scsi_error.c | 80 +++++++++++++++++++++++++++++++++++++++
 drivers/scsi/scsi_lib.c   | 10 +++++
 include/scsi/scsi_cmnd.h  | 20 ++++++++++
 3 files changed, 110 insertions(+)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 7c3eccbdd39f..d2fb28212880 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1872,6 +1872,80 @@ bool scsi_noretry_cmd(struct scsi_cmnd *scmd)
 	return false;
 }
 
+/**
+ * scsi_check_passthrough - Determine if passthrough scsi_cmnd needs a retry.
+ * @scmd: scsi_cmnd to check.
+ *
+ * Return value:
+ *	SCSI_RETURN_NOT_HANDLED - if the caller should examine the command
+ *	status because the passthrough user wanted the default error processing.
+ *	SUCCESS, FAILED or NEEDS_RETRY - if this function has determined the
+ *	command should be completed, go through the error handler due to
+ *	missing sense or should be retried.
+ */
+static enum scsi_disposition scsi_check_passthrough(struct scsi_cmnd *scmd)
+{
+	struct scsi_failure *failure;
+	struct scsi_sense_hdr sshdr;
+	enum scsi_disposition ret;
+	enum sam_status status;
+
+	if (!scmd->failures)
+		return SCSI_RETURN_NOT_HANDLED;
+
+	for (failure = scmd->failures; failure->result; failure++) {
+		if (failure->result == SCMD_FAILURE_RESULT_ANY)
+			goto maybe_retry;
+
+		if (host_byte(scmd->result) &&
+		    host_byte(scmd->result) == host_byte(failure->result))
+			goto maybe_retry;
+
+		status = status_byte(scmd->result);
+		if (!status)
+			continue;
+
+		if (failure->result == SCMD_FAILURE_STAT_ANY &&
+		    !scsi_status_is_good(scmd->result))
+			goto maybe_retry;
+
+		if (status != status_byte(failure->result))
+			continue;
+
+		if (status_byte(failure->result) != SAM_STAT_CHECK_CONDITION ||
+		    failure->sense == SCMD_FAILURE_SENSE_ANY)
+			goto maybe_retry;
+
+		ret = scsi_start_sense_processing(scmd, &sshdr);
+		if (ret == NEEDS_RETRY)
+			goto maybe_retry;
+		else if (ret != SUCCESS)
+			return ret;
+
+		if (failure->sense != sshdr.sense_key)
+			continue;
+
+		if (failure->asc == SCMD_FAILURE_ASC_ANY)
+			goto maybe_retry;
+
+		if (failure->asc != sshdr.asc)
+			continue;
+
+		if (failure->ascq == SCMD_FAILURE_ASCQ_ANY ||
+		    failure->ascq == sshdr.ascq)
+			goto maybe_retry;
+	}
+
+	return SCSI_RETURN_NOT_HANDLED;
+
+maybe_retry:
+	if (failure->allowed == SCMD_FAILURE_NO_LIMIT ||
+	    ++failure->retries <= failure->allowed)
+		return NEEDS_RETRY;
+
+	return SUCCESS;
+}
+
 /**
  * scsi_decide_disposition - Disposition a cmd on return from LLD.
  * @scmd:	SCSI cmd to examine.
@@ -1900,6 +1974,12 @@ enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
 		return SUCCESS;
 	}
 
+	if (scmd->result && blk_rq_is_passthrough(scsi_cmd_to_rq(scmd))) {
+		rtn = scsi_check_passthrough(scmd);
+		if (rtn != SCSI_RETURN_NOT_HANDLED)
+			return rtn;
+	}
+
 	/*
 	 * first check the host byte, to see if there is anything in there
 	 * that would indicate what we need to do.
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index ad9afae49544..68f4bee73ff2 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -184,6 +184,15 @@ void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 	__scsi_queue_insert(cmd, reason, true);
 }
 
+void scsi_reset_failures(struct scsi_failure *failures)
+{
+	struct scsi_failure *failure;
+
+	for (failure = failures; failure->result; failure++)
+		failure->retries = 0;
+}
+EXPORT_SYMBOL_GPL(scsi_reset_failures);
+
 /**
  * scsi_execute_cmd - insert request and wait for the result
  * @sdev:	scsi_device
@@ -1129,6 +1138,7 @@ static void scsi_initialize_rq(struct request *rq)
 	init_rcu_head(&cmd->rcu);
 	cmd->jiffies_at_alloc = jiffies;
 	cmd->retries = 0;
+	cmd->failures = NULL;
 }
 
 struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 526def14e7fb..9a3908614dc9 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -71,6 +71,23 @@ enum scsi_cmnd_submitter {
 	SUBMITTED_BY_SCSI_RESET_IOCTL = 2,
 } __packed;
 
+#define SCMD_FAILURE_RESULT_ANY	0x7fffffff
+#define SCMD_FAILURE_STAT_ANY	0xff
+#define SCMD_FAILURE_SENSE_ANY	0xff
+#define SCMD_FAILURE_ASC_ANY	0xff
+#define SCMD_FAILURE_ASCQ_ANY	0xff
+#define SCMD_FAILURE_NO_LIMIT	-1
+
+struct scsi_failure {
+	int result;
+	u8 sense;
+	u8 asc;
+	u8 ascq;
+
+	s8 allowed;
+	s8 retries;
+};
+
 struct scsi_cmnd {
 	struct scsi_device *device;
 	struct list_head eh_entry; /* entry for the host eh_abort_list/eh_cmd_q */
@@ -91,6 +108,8 @@ struct scsi_cmnd {
 
 	int retries;
 	int allowed;
+	/* optional array of failures that passthrough users want retried */
+	struct scsi_failure *failures;
 
 	unsigned char prot_op;
 	unsigned char prot_type;
@@ -394,5 +413,6 @@ extern void scsi_build_sense(struct scsi_cmnd *scmd, int desc,
 
 struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
 				   blk_mq_req_flags_t flags);
+void scsi_reset_failures(struct scsi_failure *failures);
 
 #endif /* _SCSI_SCSI_CMND_H */
-- 
2.34.1

Re: [PATCH v10 02/33] scsi: Allow passthrough to override what errors to retry

[Bart Van Assche]

On 7/14/23 14:33, Mike Christie wrote:
> diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
> index 526def14e7fb..9a3908614dc9 100644
> --- a/include/scsi/scsi_cmnd.h
> +++ b/include/scsi/scsi_cmnd.h
> @@ -71,6 +71,23 @@ enum scsi_cmnd_submitter {
>   	SUBMITTED_BY_SCSI_RESET_IOCTL = 2,
>   } __packed;
>   
> +#define SCMD_FAILURE_RESULT_ANY	0x7fffffff
> +#define SCMD_FAILURE_STAT_ANY	0xff
> +#define SCMD_FAILURE_SENSE_ANY	0xff
> +#define SCMD_FAILURE_ASC_ANY	0xff
> +#define SCMD_FAILURE_ASCQ_ANY	0xff
> +#define SCMD_FAILURE_NO_LIMIT	-1

A comment that explains the meaning of SCMD_FAILURE_RESULT_ANY and
SCMD_FAILURE_NO_LIMIT would be welcome. Does SCMD_FAILURE_RESULT_ANY 
e.g. retry only negative values of scmd->result, only positive or both?

I assume that SCMD_FAILURE_NO_LIMIT means that there is no limit on the 
number of retries?

Thanks,

Bart.

Re: [PATCH v10 02/33] scsi: Allow passthrough to override what errors to retry

[Mike Christie]

On 7/17/23 11:59 AM, Bart Van Assche wrote:
> On 7/14/23 14:33, Mike Christie wrote:
>> diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
>> index 526def14e7fb..9a3908614dc9 100644
>> --- a/include/scsi/scsi_cmnd.h
>> +++ b/include/scsi/scsi_cmnd.h
>> @@ -71,6 +71,23 @@ enum scsi_cmnd_submitter {
>>       SUBMITTED_BY_SCSI_RESET_IOCTL = 2,
>>   } __packed;
>>   +#define SCMD_FAILURE_RESULT_ANY    0x7fffffff
>> +#define SCMD_FAILURE_STAT_ANY    0xff
>> +#define SCMD_FAILURE_SENSE_ANY    0xff
>> +#define SCMD_FAILURE_ASC_ANY    0xff
>> +#define SCMD_FAILURE_ASCQ_ANY    0xff
>> +#define SCMD_FAILURE_NO_LIMIT    -1
> 
> A comment that explains the meaning of SCMD_FAILURE_RESULT_ANY and
> SCMD_FAILURE_NO_LIMIT would be welcome. Does SCMD_FAILURE_RESULT_ANY e.g. retry only negative values of scmd->result, only positive or both?

The retries in this patchset are only for when result > 0.

> 
> I assume that SCMD_FAILURE_NO_LIMIT means that there is no limit on the number of retries?
> 

Yes.

Will add some comments.

> Thanks,
> 
> Bart.

[PATCH v10 03/33] scsi: Add scsi_failure field to scsi_exec_args

[Mike Christie]

Allow SCSI execution callers to pass in a list of failures they want
retried.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
---
 drivers/scsi/scsi_lib.c    | 1 +
 include/scsi/scsi_device.h | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 68f4bee73ff2..0097166814a0 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -237,6 +237,7 @@ int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
 	scmd->cmd_len = COMMAND_SIZE(cmd[0]);
 	memcpy(scmd->cmnd, cmd, scmd->cmd_len);
 	scmd->allowed = retries;
+	scmd->failures = args->failures;
 	scmd->flags |= args->scmd_flags;
 	req->timeout = timeout;
 	req->rq_flags |= RQF_QUIET;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 75b2235b99e2..accf6c80591b 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -14,6 +14,7 @@ struct bsg_device;
 struct device;
 struct request_queue;
 struct scsi_cmnd;
+struct scsi_failure;
 struct scsi_lun;
 struct scsi_sense_hdr;
 
@@ -472,6 +473,7 @@ struct scsi_exec_args {
 	blk_mq_req_flags_t req_flags;	/* BLK_MQ_REQ flags */
 	int scmd_flags;			/* SCMD flags */
 	int *resid;			/* residual length */
+	struct scsi_failure *failures;	/* failures to retry */
 };
 
 int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
-- 
2.34.1

[PATCH v10 04/33] scsi: Have scsi-ml retry scsi_probe_lun errors

[Mike Christie]

This has scsi_probe_lun ask scsi-ml to retry UAs instead of driving them
itself.

There is one behavior change with this patch. We used to get a total of
3 retries for both UAs we were checking for. We now get 3 retries for
each.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
---
 drivers/scsi/scsi_scan.c | 42 +++++++++++++++++++++++-----------------
 1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index aa13feb17c62..39070d9e2d11 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -647,10 +647,29 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
 	int response_len = 0;
 	int pass, count, result, resid;
-	struct scsi_sense_hdr sshdr;
+	/*
+	 * not-ready to ready transition [asc/ascq=0x28/0x0] or power-on,
+	 * reset [asc/ascq=0x29/0x0], continue. INQUIRY should not yield
+	 * UNIT_ATTENTION but many buggy devices do so anyway.
+	 */
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x28,
+			.allowed = 3,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x29,
+			.allowed = 3,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
-		.sshdr = &sshdr,
 		.resid = &resid,
+		.failures = failures,
 	};
 
 	*bflags = 0;
@@ -668,6 +687,8 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 				pass, try_inquiry_len));
 
 	/* Each pass gets up to three chances to ignore Unit Attention */
+	scsi_reset_failures(failures);
+
 	for (count = 0; count < 3; ++count) {
 		memset(scsi_cmd, 0, 6);
 		scsi_cmd[0] = INQUIRY;
@@ -684,22 +705,7 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 				"scsi scan: INQUIRY %s with code 0x%x\n",
 				result ? "failed" : "successful", result));
 
-		if (result > 0) {
-			/*
-			 * not-ready to ready transition [asc/ascq=0x28/0x0]
-			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
-			 * INQUIRY should not yield UNIT_ATTENTION
-			 * but many buggy devices do so anyway. 
-			 */
-			if (scsi_status_is_check_condition(result) &&
-			    scsi_sense_valid(&sshdr)) {
-				if ((sshdr.sense_key == UNIT_ATTENTION) &&
-				    ((sshdr.asc == 0x28) ||
-				     (sshdr.asc == 0x29)) &&
-				    (sshdr.ascq == 0))
-					continue;
-			}
-		} else if (result == 0) {
+		if (result == 0) {
 			/*
 			 * if nothing was transferred, we try
 			 * again. It's a workaround for some USB
-- 
2.34.1

Re: [PATCH v10 04/33] scsi: Have scsi-ml retry scsi_probe_lun errors

[Bart Van Assche]

On 7/14/23 14:33, Mike Christie wrote:
> This has scsi_probe_lun ask scsi-ml to retry UAs instead of driving them
> itself.
> 
> There is one behavior change with this patch. We used to get a total of
> 3 retries for both UAs we were checking for. We now get 3 retries for
> each.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

[PATCH v10 05/33] scsi: retry INQUIRY after timeout

[Mike Christie]

Description from: Martin Wilck <mwilck@suse.com>:

The SCSI mid layer doesn't retry commands after DID_TIME_OUT (see
scsi_noretry_cmd()). Packet loss in the fabric can cause spurious timeouts
during SCSI device probing, causing device probing to fail. This has been
observed in FCoE uplink failover tests, for example.

This patch fixes the issue by retrying the INQUIRY.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi_scan.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 39070d9e2d11..e3c8edb92164 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -665,6 +665,10 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 			.allowed = 3,
 			.result = SAM_STAT_CHECK_CONDITION,
 		},
+		{
+			.allowed = 1,
+			.result = DID_TIME_OUT << 16,
+		},
 		{}
 	};
 	const struct scsi_exec_args exec_args = {
-- 
2.34.1

[PATCH v10 06/33] scsi: sd: Fix sshdr use in read_capacity_16

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 68b12afa0721..755b09beff2a 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2427,11 +2427,10 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
 		the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN,
 					      buffer, RC16_LEN, SD_TIMEOUT,
 					      sdkp->max_retries, &exec_args);
-
-		if (media_not_present(sdkp, &sshdr))
-			return -ENODEV;
-
 		if (the_result > 0) {
+			if (media_not_present(sdkp, &sshdr))
+				return -ENODEV;
+
 			sense_valid = scsi_sense_valid(&sshdr);
 			if (sense_valid &&
 			    sshdr.sense_key == ILLEGAL_REQUEST &&
-- 
2.34.1

Re: [PATCH v10 06/33] scsi: sd: Fix sshdr use in read_capacity_16

[John Garry]

On 14/07/2023 22:33, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

Re: [PATCH v10 06/33] scsi: sd: Fix sshdr use in read_capacity_16

[Bart Van Assche]

On 7/14/23 14:33, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

[PATCH v10 07/33] scsi: sd: Have scsi-ml retry read_capacity_16 errors

[Mike Christie]

This has read_capacity_16 have scsi-ml retry errors instead of driving
them itself.

There are 2 behavior changes with this patch:
1. There is one behavior change where we no longer retry when
scsi_execute_cmd returns < 0, but we should be ok. We don't need to retry
for failures like the queue being removed, and for the case where there
are no tags/reqs since the block layer waits/retries for us. For possible
memory allocation failures from blk_rq_map_kern we use GFP_NOIO, so
retrying will probably not help.
2. For the specific UAs we checked for and retried, we would get
READ_CAPACITY_RETRIES_ON_RESET retries plus whatever retries were left
from the loop's retries. Each UA now gets READ_CAPACITY_RETRIES_ON_RESET
reties, and the other errors (not including medium not present) get up
to 3 retries.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 106 ++++++++++++++++++++++++++++++----------------
 1 file changed, 69 insertions(+), 37 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 755b09beff2a..245419fe9358 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2402,55 +2402,87 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
 static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
 						unsigned char *buffer)
 {
-	unsigned char cmd[16];
+	static const u8 cmd[16] = { SERVICE_ACTION_IN_16, SAI_READ_CAPACITY_16,
+				    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, RC16_LEN };
 	struct scsi_sense_hdr sshdr;
-	const struct scsi_exec_args exec_args = {
-		.sshdr = &sshdr,
-	};
 	int sense_valid = 0;
 	int the_result;
-	int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;
 	unsigned int alignment;
 	unsigned long long lba;
 	unsigned sector_size;
+	struct scsi_failure failures[] = {
+		/*
+		 * Fail immediately for Invalid Command Operation Code or
+		 * Invalid Field in CDB.
+		 */
+		{
+			.sense = ILLEGAL_REQUEST,
+			.asc = 0x20,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = ILLEGAL_REQUEST,
+			.asc = 0x24,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		/* Fail immediately for Medium Not Present */
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x3A,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = NOT_READY,
+			.asc = 0x3A,
+			.ascq = 0x0,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x29,
+			/* Device reset might occur several times */
+			.allowed = READ_CAPACITY_RETRIES_ON_RESET,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		/* Any other error not listed above retry */
+		{
+			.result = SCMD_FAILURE_RESULT_ANY,
+			.allowed = 3,
+		},
+		{}
+	};
+	const struct scsi_exec_args exec_args = {
+		.sshdr = &sshdr,
+		.failures = failures,
+	};
 
 	if (sdp->no_read_capacity_16)
 		return -EINVAL;
 
-	do {
-		memset(cmd, 0, 16);
-		cmd[0] = SERVICE_ACTION_IN_16;
-		cmd[1] = SAI_READ_CAPACITY_16;
-		cmd[13] = RC16_LEN;
-		memset(buffer, 0, RC16_LEN);
-
-		the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN,
-					      buffer, RC16_LEN, SD_TIMEOUT,
-					      sdkp->max_retries, &exec_args);
-		if (the_result > 0) {
-			if (media_not_present(sdkp, &sshdr))
-				return -ENODEV;
+	memset(buffer, 0, RC16_LEN);
 
-			sense_valid = scsi_sense_valid(&sshdr);
-			if (sense_valid &&
-			    sshdr.sense_key == ILLEGAL_REQUEST &&
-			    (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
-			    sshdr.ascq == 0x00)
-				/* Invalid Command Operation Code or
-				 * Invalid Field in CDB, just retry
-				 * silently with RC10 */
-				return -EINVAL;
-			if (sense_valid &&
-			    sshdr.sense_key == UNIT_ATTENTION &&
-			    sshdr.asc == 0x29 && sshdr.ascq == 0x00)
-				/* Device reset might occur several times,
-				 * give it one more chance */
-				if (--reset_retries > 0)
-					continue;
-		}
-		retries--;
+	the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, buffer,
+				      RC16_LEN, SD_TIMEOUT, sdkp->max_retries,
+				      &exec_args);
 
-	} while (the_result && retries);
+	if (the_result > 0) {
+		if (media_not_present(sdkp, &sshdr))
+			return -ENODEV;
+
+		sense_valid = scsi_sense_valid(&sshdr);
+		if (sense_valid && sshdr.sense_key == ILLEGAL_REQUEST &&
+		    (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
+		     sshdr.ascq == 0x00)
+			/*
+			 * Invalid Command Operation Code or Invalid Field in
+			 * CDB, just retry silently with RC10
+			 */
+			return -EINVAL;
+	}
 
 	if (the_result) {
 		sd_print_result(sdkp, "Read Capacity(16) failed", the_result);
-- 
2.34.1

Re: [PATCH v10 07/33] scsi: sd: Have scsi-ml retry read_capacity_16 errors

[John Garry]

On 14/07/2023 22:33, Mike Christie wrote:
> This has read_capacity_16 have scsi-ml retry errors instead of driving
> them itself.
> 
> There are 2 behavior changes with this patch:
> 1. There is one behavior change where we no longer retry when
> scsi_execute_cmd returns < 0, but we should be ok. We don't need to retry
> for failures like the queue being removed, and for the case where there
> are no tags/reqs since the block layer waits/retries for us. For possible
> memory allocation failures from blk_rq_map_kern we use GFP_NOIO, so
> retrying will probably not help.
> 2. For the specific UAs we checked for and retried, we would get
> READ_CAPACITY_RETRIES_ON_RESET retries plus whatever retries were left
> from the loop's retries. Each UA now gets READ_CAPACITY_RETRIES_ON_RESET
> reties, and the other errors (not including medium not present) get up
> to 3 retries.
> 
> Signed-off-by: Mike Christie <michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Regardless of a couple of nitpicks, below:

Reviewed-by: John Garry <john.g.garry@oracle.com>

> ---
>   drivers/scsi/sd.c | 106 ++++++++++++++++++++++++++++++----------------
>   1 file changed, 69 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 755b09beff2a..245419fe9358 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -2402,55 +2402,87 @@ static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device *sdp,
>   static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
>   						unsigned char *buffer)
>   {
> -	unsigned char cmd[16];
> +	static const u8 cmd[16] = { SERVICE_ACTION_IN_16, SAI_READ_CAPACITY_16,
> +				    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, RC16_LEN };

In terms of coding style, could you follow previous style, like:
	static const u8 cmd[16] = {
		[0] = SERVICE_ACTION_IN_16,
		[1] = SAI_READ_CAPACITY_16,
		[13] = RC16_LEN,
	};
	
Seems safe to me (to ensure we fill in the correct array element).

>   	struct scsi_sense_hdr sshdr;
> -	const struct scsi_exec_args exec_args = {
> -		.sshdr = &sshdr,
> -	};
>   	int sense_valid = 0;
>   	int the_result;
> -	int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;
>   	unsigned int alignment;
>   	unsigned long long lba;
>   	unsigned sector_size;
> +	struct scsi_failure failures[] = {
> +		/*
> +		 * Fail immediately for Invalid Command Operation Code or
> +		 * Invalid Field in CDB.
> +		 */
> +		{
> +			.sense = ILLEGAL_REQUEST,
> +			.asc = 0x20,
> +			.allowed = 0,
> +			.result = SAM_STAT_CHECK_CONDITION,
> +		},
> +		{
> +			.sense = ILLEGAL_REQUEST,
> +			.asc = 0x24,
> +			.allowed = 0,
> +			.result = SAM_STAT_CHECK_CONDITION,
> +		},
> +		/* Fail immediately for Medium Not Present */
> +		{
> +			.sense = UNIT_ATTENTION,
> +			.asc = 0x3A,
> +			.allowed = 0,
> +			.result = SAM_STAT_CHECK_CONDITION,
> +		},
> +		{
> +			.sense = NOT_READY,
> +			.asc = 0x3A,
> +			.ascq = 0x0,
> +			.allowed = 0,
> +			.result = SAM_STAT_CHECK_CONDITION,
> +		},
> +		{
> +			.sense = UNIT_ATTENTION,
> +			.asc = 0x29,
> +			/* Device reset might occur several times */
> +			.allowed = READ_CAPACITY_RETRIES_ON_RESET,
> +			.result = SAM_STAT_CHECK_CONDITION,
> +		},
> +		/* Any other error not listed above retry */
> +		{
> +			.result = SCMD_FAILURE_RESULT_ANY,
> +			.allowed = 3,
> +		},
> +		{}
> +	};
> +	const struct scsi_exec_args exec_args = {
> +		.sshdr = &sshdr,
> +		.failures = failures,
> +	};
>   
>   	if (sdp->no_read_capacity_16)
>   		return -EINVAL;
>   
> -	do {
> -		memset(cmd, 0, 16);
> -		cmd[0] = SERVICE_ACTION_IN_16;
> -		cmd[1] = SAI_READ_CAPACITY_16;
> -		cmd[13] = RC16_LEN;
> -		memset(buffer, 0, RC16_LEN);
> -
> -		the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN,
> -					      buffer, RC16_LEN, SD_TIMEOUT,
> -					      sdkp->max_retries, &exec_args);
> -		if (the_result > 0) {
> -			if (media_not_present(sdkp, &sshdr))
> -				return -ENODEV;
> +	memset(buffer, 0, RC16_LEN);
>   
> -			sense_valid = scsi_sense_valid(&sshdr);
> -			if (sense_valid &&
> -			    sshdr.sense_key == ILLEGAL_REQUEST &&
> -			    (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
> -			    sshdr.ascq == 0x00)
> -				/* Invalid Command Operation Code or
> -				 * Invalid Field in CDB, just retry
> -				 * silently with RC10 */
> -				return -EINVAL;
> -			if (sense_valid &&
> -			    sshdr.sense_key == UNIT_ATTENTION &&
> -			    sshdr.asc == 0x29 && sshdr.ascq == 0x00)
> -				/* Device reset might occur several times,
> -				 * give it one more chance */
> -				if (--reset_retries > 0)
> -					continue;
> -		}
> -		retries--;
> +	the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, buffer,
> +				      RC16_LEN, SD_TIMEOUT, sdkp->max_retries,
> +				      &exec_args);
>   
> -	} while (the_result && retries);
> +	if (the_result > 0) {
> +		if (media_not_present(sdkp, &sshdr))
> +			return -ENODEV;
> +
> +		sense_valid = scsi_sense_valid(&sshdr);
> +		if (sense_valid && sshdr.sense_key == ILLEGAL_REQUEST &&
> +		    (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
> +		     sshdr.ascq == 0x00)
> +			/*
> +			 * Invalid Command Operation Code or Invalid Field in
> +			 * CDB, just retry silently with RC10
> +			 */
> +			return -EINVAL;


nit: personally I would use {} here, like below, but that's your choice.


  (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
		     sshdr.ascq == 0x00) {
			/*
			 * Invalid Command Operation Code or Invalid Field in
			 * CDB, just retry silently with RC10
			 */
			return -EINVAL;
}

> +	}
>   
>   	if (the_result) {
>   		sd_print_result(sdkp, "Read Capacity(16) failed", the_result);

Re: [PATCH v10 07/33] scsi: sd: Have scsi-ml retry read_capacity_16 errors

[Mike Christie]

On 7/17/23 10:43 AM, John Garry wrote:
>>
>> -    unsigned char cmd[16];
>> +    static const u8 cmd[16] = { SERVICE_ACTION_IN_16, SAI_READ_CAPACITY_16,
>> +                    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, RC16_LEN };
> 
> In terms of coding style, could you follow previous style, like:
>     static const u8 cmd[16] = {
>         [0] = SERVICE_ACTION_IN_16,
>         [1] = SAI_READ_CAPACITY_16,
>         [13] = RC16_LEN,
>     };
>     
> Seems safe to me (to ensure we fill in the correct array element).
> 

That's nice. Will fix throughout the patchset.

>> +
>> +        sense_valid = scsi_sense_valid(&sshdr);
>> +        if (sense_valid && sshdr.sense_key == ILLEGAL_REQUEST &&
>> +            (sshdr.asc == 0x20 || sshdr.asc == 0x24) &&
>> +             sshdr.ascq == 0x00)
>> +            /*
>> +             * Invalid Command Operation Code or Invalid Field in
>> +             * CDB, just retry silently with RC10
>> +             */
>> +            return -EINVAL;
> 
> 
> nit: personally I would use {} here, like below, but that's your choice.
> 

Yeah, I like the {} when there's comments. I've got the not needed comment
in other patches so I just kept the previous style.

Re: [PATCH v10 07/33] scsi: sd: Have scsi-ml retry read_capacity_16 errors

[Bart Van Assche]

On 7/14/23 14:33, Mike Christie wrote:
> This has read_capacity_16 have scsi-ml retry errors instead of driving
> them itself.

Assuming John's comments will be addressed:

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

[PATCH v10 08/33] scsi: Use separate buf for START_STOP in sd_spinup_disk

[Mike Christie]

We currently re-use the cmd buffer for the TUR and START_STOP commands
which requires us to reset the buffer when retrying. This has us use
separate buffers for the 2 commands so we can make them const and I think
it makes it easier to handle for retries but does not add too much extra
to the stack use.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 245419fe9358..f75e2d7a864c 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2267,14 +2267,13 @@ sd_spinup_disk(struct scsi_disk *sdkp)
 			 * Issue command to spin up drive when not ready
 			 */
 			if (!spintime) {
+				/* Return immediately and start spin cycle */
+				const u8 start_cmd[10] = { START_STOP, 1, 0, 0,
+					sdkp->device->start_stop_pwr_cond ?
+					0x11 : 1 };
+
 				sd_printk(KERN_NOTICE, sdkp, "Spinning up disk...");
-				cmd[0] = START_STOP;
-				cmd[1] = 1;	/* Return immediately */
-				memset((void *) &cmd[2], 0, 8);
-				cmd[4] = 1;	/* Start spin cycle */
-				if (sdkp->device->start_stop_pwr_cond)
-					cmd[4] |= 1 << 4;
-				scsi_execute_cmd(sdkp->device, cmd,
+				scsi_execute_cmd(sdkp->device, start_cmd,
 						 REQ_OP_DRV_IN, NULL, 0,
 						 SD_TIMEOUT, sdkp->max_retries,
 						 &exec_args);
-- 
2.34.1

Re: [PATCH v10 08/33] scsi: Use separate buf for START_STOP in sd_spinup_disk

[John Garry]

On 14/07/2023 22:33, Mike Christie wrote:
> We currently re-use the cmd buffer for the TUR and START_STOP commands
> which requires us to reset the buffer when retrying. This has us use
> separate buffers for the 2 commands so we can make them const and I think
> it makes it easier to handle for retries but does not add too much extra
> to the stack use.
> 
> Signed-off-by: Mike Christie <michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

> ---
>   drivers/scsi/sd.c | 13 ++++++-------
>   1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index 245419fe9358..f75e2d7a864c 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -2267,14 +2267,13 @@ sd_spinup_disk(struct scsi_disk *sdkp)
>   			 * Issue command to spin up drive when not ready
>   			 */
>   			if (!spintime) {
> +				/* Return immediately and start spin cycle */
> +				const u8 start_cmd[10] = { START_STOP, 1, 0, 0,
> +					sdkp->device->start_stop_pwr_cond ?
> +					0x11 : 1 };

same comment as previous patch

> +
>   				sd_printk(KERN_NOTICE, sdkp, "Spinning up disk...");
> -				cmd[0] = START_STOP;
> -				cmd[1] = 1;	/* Return immediately */
> -				memset((void *) &cmd[2], 0, 8);
> -				cmd[4] = 1;	/* Start spin cycle */
> -				if (sdkp->device->start_stop_pwr_cond)
> -					cmd[4] |= 1 << 4;
> -				scsi_execute_cmd(sdkp->device, cmd,
> +				scsi_execute_cmd(sdkp->device, start_cmd,
>   						 REQ_OP_DRV_IN, NULL, 0,
>   						 SD_TIMEOUT, sdkp->max_retries,
>   						 &exec_args);

Re: [PATCH v10 08/33] scsi: Use separate buf for START_STOP in sd_spinup_disk

[Bart Van Assche]

On 7/17/23 08:45, John Garry wrote:
>> +                /* Return immediately and start spin cycle */
>> +                const u8 start_cmd[10] = { START_STOP, 1, 0, 0,
>> +                    sdkp->device->start_stop_pwr_cond ?
>> +                    0x11 : 1 };
> 
> same comment as previous patch

I'm not sure that using designated initializers for initializing only the
first five elements will improve readability ...

Thanks,

Bart.

Re: [PATCH v10 08/33] scsi: Use separate buf for START_STOP in sd_spinup_disk

[Bart Van Assche]

On 7/14/23 14:33, Mike Christie wrote:
> We currently re-use the cmd buffer for the TUR and START_STOP commands
> which requires us to reset the buffer when retrying. This has us use
> separate buffers for the 2 commands so we can make them const and I think
> it makes it easier to handle for retries but does not add too much extra
> to the stack use.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

[PATCH v10 09/33] scsi: sd: Fix sshdr use in sd_spinup_disk

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index f75e2d7a864c..753f18457ea1 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2219,19 +2219,21 @@ sd_spinup_disk(struct scsi_disk *sdkp)
 						      sdkp->max_retries,
 						      &exec_args);
 
-			/*
-			 * If the drive has indicated to us that it
-			 * doesn't have any media in it, don't bother
-			 * with any more polling.
-			 */
-			if (media_not_present(sdkp, &sshdr)) {
-				if (media_was_present)
-					sd_printk(KERN_NOTICE, sdkp, "Media removed, stopped polling\n");
-				return;
-			}
+			if (the_result > 0) {
+				/*
+				 * If the drive has indicated to us that it
+				 * doesn't have any media in it, don't bother
+				 * with any more polling.
+				 */
+				if (media_not_present(sdkp, &sshdr)) {
+					if (media_was_present)
+						sd_printk(KERN_NOTICE, sdkp,
+							  "Media removed, stopped polling\n");
+					return;
+				}
 
-			if (the_result)
 				sense_valid = scsi_sense_valid(&sshdr);
+			}
 			retries++;
 		} while (retries < 3 &&
 			 (!scsi_status_is_good(the_result) ||
-- 
2.34.1

Re: [PATCH v10 09/33] scsi: sd: Fix sshdr use in sd_spinup_disk

[John Garry]

On 14/07/2023 22:33, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

Re: [PATCH v10 09/33] scsi: sd: Fix sshdr use in sd_spinup_disk

[Bart Van Assche]

On 7/14/23 14:33, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
             ^^^^^^^^
Is there perhaps a word missing here?

Anyway:

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

[PATCH v10 10/33] scsi: Have scsi-ml retry sd_spinup_disk errors

[Mike Christie]

This simplifies sd_spinup_disk so scsi-ml retries errors for it. Note that
we retried specifically on a UA and also if scsi_status_is_good returned
failed which would happen for all check conditions. In this patch we use
SCMD_FAILURE_STAT_ANY which will trigger for the same conditions as
when scsi_status_is_good returns false. This will cover all CCs including
UAs so there is no explicit failures arrary entry for UAs.

We do not handle the outside loop's retries because we want to sleep
between tries and we don't support that yet.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 73 ++++++++++++++++++++++++++---------------------
 1 file changed, 41 insertions(+), 32 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 753f18457ea1..34a1149bfff2 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2190,55 +2190,64 @@ static int sd_done(struct scsi_cmnd *SCpnt)
 static void
 sd_spinup_disk(struct scsi_disk *sdkp)
 {
-	unsigned char cmd[10];
+	static const u8 cmd[10] = { TEST_UNIT_READY };
 	unsigned long spintime_expire = 0;
-	int retries, spintime;
+	int spintime, sense_valid = 0;
 	unsigned int the_result;
 	struct scsi_sense_hdr sshdr;
+	struct scsi_failure failures[] = {
+		/* Fail immediately for Medium Not Present */
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x3A,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = NOT_READY,
+			.asc = 0x3A,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.result = SCMD_FAILURE_STAT_ANY,
+			.allowed = 3,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.sshdr = &sshdr,
+		.failures = failures,
 	};
-	int sense_valid = 0;
 
 	spintime = 0;
 
 	/* Spin up drives, as required.  Only do this at boot time */
 	/* Spinup needs to be done for module loads too. */
 	do {
-		retries = 0;
-
-		do {
-			bool media_was_present = sdkp->media_present;
+		bool media_was_present = sdkp->media_present;
 
-			cmd[0] = TEST_UNIT_READY;
-			memset((void *) &cmd[1], 0, 9);
+		scsi_reset_failures(failures);
 
-			the_result = scsi_execute_cmd(sdkp->device, cmd,
-						      REQ_OP_DRV_IN, NULL, 0,
-						      SD_TIMEOUT,
-						      sdkp->max_retries,
-						      &exec_args);
+		the_result = scsi_execute_cmd(sdkp->device, cmd, REQ_OP_DRV_IN,
+					      NULL, 0, SD_TIMEOUT,
+					      sdkp->max_retries, &exec_args);
 
-			if (the_result > 0) {
-				/*
-				 * If the drive has indicated to us that it
-				 * doesn't have any media in it, don't bother
-				 * with any more polling.
-				 */
-				if (media_not_present(sdkp, &sshdr)) {
-					if (media_was_present)
-						sd_printk(KERN_NOTICE, sdkp,
-							  "Media removed, stopped polling\n");
-					return;
-				}
 
-				sense_valid = scsi_sense_valid(&sshdr);
+		if (the_result > 0) {
+			/*
+			 * If the drive has indicated to us that it doesn't
+			 * have any media in it, don't bother with any more
+			 * polling.
+			 */
+			if (media_not_present(sdkp, &sshdr)) {
+				if (media_was_present)
+					sd_printk(KERN_NOTICE, sdkp,
+						  "Media removed, stopped polling\n");
+				return;
 			}
-			retries++;
-		} while (retries < 3 &&
-			 (!scsi_status_is_good(the_result) ||
-			  (scsi_status_is_check_condition(the_result) &&
-			  sense_valid && sshdr.sense_key == UNIT_ATTENTION)));
+			sense_valid = scsi_sense_valid(&sshdr);
+		}
 
 		if (!scsi_status_is_check_condition(the_result)) {
 			/* no sense, TUR either succeeded or failed
-- 
2.34.1

Re: [PATCH v10 10/33] scsi: Have scsi-ml retry sd_spinup_disk errors

[Bart Van Assche]

On 7/14/23 14:33, Mike Christie wrote:
> This simplifies sd_spinup_disk so scsi-ml retries errors for it. Note that
> we retried specifically on a UA and also if scsi_status_is_good returned
> failed which would happen for all check conditions. In this patch we use
> SCMD_FAILURE_STAT_ANY which will trigger for the same conditions as
> when scsi_status_is_good returns false. This will cover all CCs including
> UAs so there is no explicit failures arrary entry for UAs.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

[PATCH v10 11/33] scsi: hp_sw: Only access sshdr if res > 0

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/device_handler/scsi_dh_hp_sw.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
index 5f2f943d926c..785ab2c5391f 100644
--- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c
+++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
@@ -93,7 +93,7 @@ static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
 	res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
 			       HP_SW_RETRIES, &exec_args);
 	if (res) {
-		if (scsi_sense_valid(&sshdr))
+		if (res > 0 && scsi_sense_valid(&sshdr))
 			ret = tur_done(sdev, h, &sshdr);
 		else {
 			sdev_printk(KERN_WARNING, sdev,
@@ -134,7 +134,7 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *h)
 	res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
 			       HP_SW_RETRIES, &exec_args);
 	if (res) {
-		if (!scsi_sense_valid(&sshdr)) {
+		if (res < 0 || !scsi_sense_valid(&sshdr)) {
 			sdev_printk(KERN_WARNING, sdev,
 				    "%s: sending start_stop_unit failed, "
 				    "no sense available\n", HP_SW_NAME);
-- 
2.34.1

Re: [PATCH v10 11/33] scsi: hp_sw: Only access sshdr if res > 0

[John Garry]

On 14/07/2023 22:33, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
> 
> Signed-off-by: Mike Christie <michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Regardless of a couple of coding style comments, below:
Reviewed-by: John Garry <john.g.garry@oracle.com>

> ---
>   drivers/scsi/device_handler/scsi_dh_hp_sw.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
> index 5f2f943d926c..785ab2c5391f 100644
> --- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c
> +++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
> @@ -93,7 +93,7 @@ static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
>   	res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
>   			       HP_SW_RETRIES, &exec_args);
>   	if (res) {
> -		if (scsi_sense_valid(&sshdr))
> +		if (res > 0 && scsi_sense_valid(&sshdr))
>   			ret = tur_done(sdev, h, &sshdr);
>   		else {
>   			sdev_printk(KERN_WARNING, sdev,

maybe this is better:

	if (res > 0 && scsi_sense_valid())
		ret = tur_done(sdev, h, &sshdr);
	else if (res == 0) {
		h->path_state ...
	} else {
		sdev_printk(KERN_WARNING, sdev, ...
		ret = SCSI_DH_OK;
	}

But I am not sure about the == 0 in the middle...

> @@ -134,7 +134,7 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *h)
>   	res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
>   			       HP_SW_RETRIES, &exec_args);
>   	if (res) {
> -		if (!scsi_sense_valid(&sshdr)) {
> +		if (res < 0 || !scsi_sense_valid(&sshdr)) {
>   			sdev_printk(KERN_WARNING, sdev,
>   				    "%s: sending start_stop_unit failed, "
>   				    "no sense available\n", HP_SW_NAME);

I think that you could do something similar to above suggestion here.

Thanks,
John

[PATCH v10 12/33] scsi: hp_sw: Have scsi-ml retry scsi_exec_req errors

[Mike Christie]

This has hp_sw have scsi-ml retry scsi_exec_req errors instead of driving
them itself.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/device_handler/scsi_dh_hp_sw.c | 42 +++++++++++++--------
 1 file changed, 27 insertions(+), 15 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_hp_sw.c b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
index 785ab2c5391f..e25161aa7b77 100644
--- a/drivers/scsi/device_handler/scsi_dh_hp_sw.c
+++ b/drivers/scsi/device_handler/scsi_dh_hp_sw.c
@@ -46,9 +46,6 @@ static int tur_done(struct scsi_device *sdev, struct hp_sw_dh_data *h,
 	int ret = SCSI_DH_IO;
 
 	switch (sshdr->sense_key) {
-	case UNIT_ATTENTION:
-		ret = SCSI_DH_IMM_RETRY;
-		break;
 	case NOT_READY:
 		if (sshdr->asc == 0x04 && sshdr->ascq == 2) {
 			/*
@@ -85,11 +82,21 @@ static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
 	int ret = SCSI_DH_OK, res;
 	blk_opf_t opf = REQ_OP_DRV_IN | REQ_FAILFAST_DEV |
 				REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER;
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = SCMD_FAILURE_NO_LIMIT,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.sshdr = &sshdr,
+		.failures = failures,
 	};
 
-retry:
 	res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
 			       HP_SW_RETRIES, &exec_args);
 	if (res) {
@@ -105,8 +112,6 @@ static int hp_sw_tur(struct scsi_device *sdev, struct hp_sw_dh_data *h)
 		h->path_state = HP_SW_PATH_ACTIVE;
 		ret = SCSI_DH_OK;
 	}
-	if (ret == SCSI_DH_IMM_RETRY)
-		goto retry;
 
 	return ret;
 }
@@ -123,14 +128,28 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *h)
 	struct scsi_sense_hdr sshdr;
 	struct scsi_device *sdev = h->sdev;
 	int res, rc = SCSI_DH_OK;
-	int retry_cnt = HP_SW_RETRIES;
 	blk_opf_t opf = REQ_OP_DRV_IN | REQ_FAILFAST_DEV |
 				REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER;
+	struct scsi_failure failures[] = {
+		{
+			/*
+			 * LUN not ready - manual intervention required
+			 *
+			 * Switch-over in progress, retry.
+			 */
+			.sense = NOT_READY,
+			.asc = 0x04,
+			.ascq = 0x03,
+			.allowed = HP_SW_RETRIES,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.sshdr = &sshdr,
+		.failures = failures,
 	};
 
-retry:
 	res = scsi_execute_cmd(sdev, cmd, opf, NULL, 0, HP_SW_TIMEOUT,
 			       HP_SW_RETRIES, &exec_args);
 	if (res) {
@@ -143,13 +162,6 @@ static int hp_sw_start_stop(struct hp_sw_dh_data *h)
 		switch (sshdr.sense_key) {
 		case NOT_READY:
 			if (sshdr.asc == 0x04 && sshdr.ascq == 3) {
-				/*
-				 * LUN not ready - manual intervention required
-				 *
-				 * Switch-over in progress, retry.
-				 */
-				if (--retry_cnt)
-					goto retry;
 				rc = SCSI_DH_RETRY;
 				break;
 			}
-- 
2.34.1

Re: [PATCH v10 12/33] scsi: hp_sw: Have scsi-ml retry scsi_exec_req errors

[John Garry]

On 14/07/2023 22:33, Mike Christie wrote:
> This has hp_sw have scsi-ml retry scsi_exec_req errors instead of driving
> them itself.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 13/33] scsi: rdac: Fix sshdr use

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/device_handler/scsi_dh_rdac.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index c5538645057a..cdefaa9f614e 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -541,6 +541,7 @@ static void send_mode_select(struct work_struct *work)
 	const struct scsi_exec_args exec_args = {
 		.sshdr = &sshdr,
 	};
+	int rc;
 
 	spin_lock(&ctlr->ms_lock);
 	list_splice_init(&ctlr->ms_head, &list);
@@ -558,14 +559,18 @@ static void send_mode_select(struct work_struct *work)
 		(char *) h->ctlr->array_name, h->ctlr->index,
 		(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
 
-	if (scsi_execute_cmd(sdev, cdb, opf, &h->ctlr->mode_select, data_size,
-			     RDAC_TIMEOUT * HZ, RDAC_RETRIES, &exec_args)) {
+	rc = scsi_execute_cmd(sdev, cdb, opf, &h->ctlr->mode_select, data_size,
+			      RDAC_TIMEOUT * HZ, RDAC_RETRIES, &exec_args);
+	if (rc < 0) {
+		err = SCSI_DH_IO;
+	} else if (rc > 0) {
 		err = mode_select_handle_sense(sdev, &sshdr);
 		if (err == SCSI_DH_RETRY && retry_cnt--)
 			goto retry;
 		if (err == SCSI_DH_IMM_RETRY)
 			goto retry;
 	}
+
 	if (err == SCSI_DH_OK) {
 		h->state = RDAC_STATE_ACTIVE;
 		RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
-- 
2.34.1

Re: [PATCH v10 13/33] scsi: rdac: Fix sshdr use

[John Garry]

On 14/07/2023 22:33, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>
> ---
>   drivers/scsi/device_handler/scsi_dh_rdac.c | 9 +++++++--
>   1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
> index c5538645057a..cdefaa9f614e 100644
> --- a/drivers/scsi/device_handler/scsi_dh_rdac.c
> +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
> @@ -541,6 +541,7 @@ static void send_mode_select(struct work_struct *work)
>   	const struct scsi_exec_args exec_args = {
>   		.sshdr = &sshdr,
>   	};
> +	int rc;
>   
>   	spin_lock(&ctlr->ms_lock);
>   	list_splice_init(&ctlr->ms_head, &list);
> @@ -558,14 +559,18 @@ static void send_mode_select(struct work_struct *work)
>   		(char *) h->ctlr->array_name, h->ctlr->index,
>   		(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
>   
> -	if (scsi_execute_cmd(sdev, cdb, opf, &h->ctlr->mode_select, data_size,
> -			     RDAC_TIMEOUT * HZ, RDAC_RETRIES, &exec_args)) {
> +	rc = scsi_execute_cmd(sdev, cdb, opf, &h->ctlr->mode_select, data_size,
> +			      RDAC_TIMEOUT * HZ, RDAC_RETRIES, &exec_args);
> +	if (rc < 0) {
> +		err = SCSI_DH_IO;
> +	} else if (rc > 0) {
>   		err = mode_select_handle_sense(sdev, &sshdr);
>   		if (err == SCSI_DH_RETRY && retry_cnt--)
>   			goto retry;
>   		if (err == SCSI_DH_IMM_RETRY)
>   			goto retry;
>   	}
> +
>   	if (err == SCSI_DH_OK) {
As I see, err is initially set to SCSI_DH_OK when declared. Then if we 
need to retry and 2nd call to scsi_execute_cmd() passes, such that rc == 
0, then err still holds the old value. This seems same as pre-existing 
behaviour - is this proper?

Thanks,
John

Re: [PATCH v10 13/33] scsi: rdac: Fix sshdr use

[Mike Christie]

On 7/18/23 8:25 AM, John Garry wrote:
> On 14/07/2023 22:33, Mike Christie wrote:
>> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
>> shouldn't access the sshdr. If it returns 0, then the cmd executed
>> successfully, so there is no need to check the sshdr. This has us access
>> the sshdr when get a return value > 0.
>>
>> Signed-off-by: Mike Christie<michael.christie@oracle.com>
>> Reviewed-by: Christoph Hellwig<hch@lst.de>
>> ---
>>   drivers/scsi/device_handler/scsi_dh_rdac.c | 9 +++++++--
>>   1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
>> index c5538645057a..cdefaa9f614e 100644
>> --- a/drivers/scsi/device_handler/scsi_dh_rdac.c
>> +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
>> @@ -541,6 +541,7 @@ static void send_mode_select(struct work_struct *work)
>>       const struct scsi_exec_args exec_args = {
>>           .sshdr = &sshdr,
>>       };
>> +    int rc;
>>         spin_lock(&ctlr->ms_lock);
>>       list_splice_init(&ctlr->ms_head, &list);
>> @@ -558,14 +559,18 @@ static void send_mode_select(struct work_struct *work)
>>           (char *) h->ctlr->array_name, h->ctlr->index,
>>           (retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
>>   -    if (scsi_execute_cmd(sdev, cdb, opf, &h->ctlr->mode_select, data_size,
>> -                 RDAC_TIMEOUT * HZ, RDAC_RETRIES, &exec_args)) {
>> +    rc = scsi_execute_cmd(sdev, cdb, opf, &h->ctlr->mode_select, data_size,
>> +                  RDAC_TIMEOUT * HZ, RDAC_RETRIES, &exec_args);
>> +    if (rc < 0) {
>> +        err = SCSI_DH_IO;
>> +    } else if (rc > 0) {
>>           err = mode_select_handle_sense(sdev, &sshdr);
>>           if (err == SCSI_DH_RETRY && retry_cnt--)
>>               goto retry;
>>           if (err == SCSI_DH_IMM_RETRY)
>>               goto retry;
>>       }
>> +
>>       if (err == SCSI_DH_OK) {
> As I see, err is initially set to SCSI_DH_OK when declared. Then if we need to retry and 2nd call to scsi_execute_cmd() passes, such that rc == 0, then err still holds the old value. This seems same as pre-existing behaviour - is this proper?

I guess this has been working by accident.

When that happens we end up returning one of the retryable error codes
to dm-multipath. It will then recall us, and before we re-run this
function we will run check_ownership and see that the last call worked.

Re: [PATCH v10 13/33] scsi: rdac: Fix sshdr use

[John Garry]

On 18/07/2023 16:31, Mike Christie wrote:

Hi Mike,

>>> +
>>>        if (err == SCSI_DH_OK) {
>> As I see, err is initially set to SCSI_DH_OK when declared. Then if we need to retry and 2nd call to scsi_execute_cmd() passes, such that rc == 0, then err still holds the old value. This seems same as pre-existing behaviour - is this proper?
> I guess this has been working by accident.
> 
> When that happens we end up returning one of the retryable error codes
> to dm-multipath. It will then recall us, and before we re-run this
> function we will run check_ownership and see that the last call worked.
> 

I'd suggest that we fix this up as a prep patch, if you don't mind.

Thanks,
John

Re: [PATCH v10 13/33] scsi: rdac: Fix sshdr use

[Mike Christie]

On 7/19/23 9:44 AM, John Garry wrote:
> On 18/07/2023 16:31, Mike Christie wrote:
> 
> Hi Mike,
> 
>>>> +
>>>>        if (err == SCSI_DH_OK) {
>>> As I see, err is initially set to SCSI_DH_OK when declared. Then if we need to retry and 2nd call to scsi_execute_cmd() passes, such that rc == 0, then err still holds the old value. This seems same as pre-existing behaviour - is this proper?
>> I guess this has been working by accident.
>>
>> When that happens we end up returning one of the retryable error codes
>> to dm-multipath. It will then recall us, and before we re-run this
>> function we will run check_ownership and see that the last call worked.
>>
> 
> I'd suggest that we fix this up as a prep patch, if you don't mind.
> 
Do you mean just change the description of this patch to reflect it fixes the
second bug? It already is a prep patch. The second rdac patch is built over it.
stable can take the sshdr fix patches without the API change ones if they want.

I just put the sshdr one next to the API change one, so reviewers wouldn't
have to jump back and forth between the front and back of the patchset.

Do you mean move all the sshd hdr patches to a separate patchset?

Re: [PATCH v10 13/33] scsi: rdac: Fix sshdr use

[John Garry]

On 22/07/2023 18:10, Mike Christie wrote:
>>>> As I see, err is initially set to SCSI_DH_OK when declared. Then if we need to retry and 2nd call to scsi_execute_cmd() passes, such that rc == 0, then err still holds the old value. This seems same as pre-existing behaviour - is this proper?
>>> I guess this has been working by accident.
>>>
>>> When that happens we end up returning one of the retryable error codes
>>> to dm-multipath. It will then recall us, and before we re-run this
>>> function we will run check_ownership and see that the last call worked.
>>>

Hi Mike,

>> I'd suggest that we fix this up as a prep patch, if you don't mind.
>>
> Do you mean just change the description of this patch to reflect it fixes the
> second bug? It already is a prep patch. The second rdac patch is built over it.

AFAICS, this patch does not fix the bug where @err may hold a stale 
value. However this broken code goes away later in the series.

> stable can take the sshdr fix patches without the API change ones if they want.
> 
> I just put the sshdr one next to the API change one, so reviewers wouldn't
> have to jump back and forth between the front and back of the patchset.
> 
> Do you mean move all the sshd hdr patches to a separate patchset?
No, I was just suggesting that we fix the broken code also in a separate 
patch in this series, like:

diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c
b/drivers/scsi/device_handler/scsi_dh_rdac.c
index c5538645057a..5d338f12e68b 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -530,7 +530,7 @@ static void send_mode_select(struct work_struct *work)
                container_of(work, struct rdac_controller, ms_work);
        struct scsi_device *sdev = ctlr->ms_sdev;
        struct rdac_dh_data *h = sdev->handler_data;
-       int err = SCSI_DH_OK, retry_cnt = RDAC_RETRY_COUNT;
+       int err, retry_cnt = RDAC_RETRY_COUNT;
        struct rdac_queue_data *tmp, *qdata;
        LIST_HEAD(list);
        unsigned char cdb[MAX_COMMAND_SIZE];
@@ -549,6 +549,7 @@ static void send_mode_select(struct work_struct *work)
        spin_unlock(&ctlr->ms_lock);

  retry:
+       err = SCSI_DH_OK;
        memset(cdb, 0, sizeof(cdb));

        data_size = rdac_failover_get(ctlr, &list, cdb);

Thanks,
John

Re: [PATCH v10 13/33] scsi: rdac: Fix sshdr use

[Mike Christie]

On 7/25/23 02:59, John Garry wrote:
> On 22/07/2023 18:10, Mike Christie wrote:
>>>>> As I see, err is initially set to SCSI_DH_OK when declared. Then if we need to retry and 2nd call to scsi_execute_cmd() passes, such that rc == 0, then err still holds the old value. This seems same as pre-existing behaviour - is this proper?
>>>> I guess this has been working by accident.
>>>>
>>>> When that happens we end up returning one of the retryable error codes
>>>> to dm-multipath. It will then recall us, and before we re-run this
>>>> function we will run check_ownership and see that the last call worked.
>>>>
> 
> Hi Mike,
> 
>>> I'd suggest that we fix this up as a prep patch, if you don't mind.
>>>
>> Do you mean just change the description of this patch to reflect it fixes the
>> second bug? It already is a prep patch. The second rdac patch is built over it.
> 
> AFAICS, this patch does not fix the bug where @err may hold a stale value. However this broken code goes away later in the series.
> 

Ah shoot, you're right. I should have stayed on vacation one more day :)

>> stable can take the sshdr fix patches without the API change ones if they want.
>>
>> I just put the sshdr one next to the API change one, so reviewers wouldn't
>> have to jump back and forth between the front and back of the patchset.
>>
>> Do you mean move all the sshd hdr patches to a separate patchset?
> No, I was just suggesting that we fix the broken code also in a separate patch in this series, like:
> 

Got it. I'll add that patch to the series.

[PATCH v10 14/33] scsi: rdac: Have scsi-ml retry send_mode_select errors

[Mike Christie]

This has rdac have scsi-ml retry errors instead of driving them itself.

There is one behavior change with this patch. We used to get a total of
5 retries for errors mode_select_handle_sense returned SCSI_DH_RETRY. We
now get 5 retries for each failure.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/device_handler/scsi_dh_rdac.c | 92 ++++++++++++----------
 1 file changed, 51 insertions(+), 41 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c
index cdefaa9f614e..1db217be4db4 100644
--- a/drivers/scsi/device_handler/scsi_dh_rdac.c
+++ b/drivers/scsi/device_handler/scsi_dh_rdac.c
@@ -485,43 +485,17 @@ static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
 static int mode_select_handle_sense(struct scsi_device *sdev,
 				    struct scsi_sense_hdr *sense_hdr)
 {
-	int err = SCSI_DH_IO;
 	struct rdac_dh_data *h = sdev->handler_data;
 
 	if (!scsi_sense_valid(sense_hdr))
-		goto done;
-
-	switch (sense_hdr->sense_key) {
-	case NO_SENSE:
-	case ABORTED_COMMAND:
-	case UNIT_ATTENTION:
-		err = SCSI_DH_RETRY;
-		break;
-	case NOT_READY:
-		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
-			/* LUN Not Ready and is in the Process of Becoming
-			 * Ready
-			 */
-			err = SCSI_DH_RETRY;
-		break;
-	case ILLEGAL_REQUEST:
-		if (sense_hdr->asc == 0x91 && sense_hdr->ascq == 0x36)
-			/*
-			 * Command Lock contention
-			 */
-			err = SCSI_DH_IMM_RETRY;
-		break;
-	default:
-		break;
-	}
+		return SCSI_DH_IO;
 
 	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
 		"MODE_SELECT returned with sense %02x/%02x/%02x",
 		(char *) h->ctlr->array_name, h->ctlr->index,
 		sense_hdr->sense_key, sense_hdr->asc, sense_hdr->ascq);
 
-done:
-	return err;
+	return SCSI_DH_IO;
 }
 
 static void send_mode_select(struct work_struct *work)
@@ -530,7 +504,7 @@ static void send_mode_select(struct work_struct *work)
 		container_of(work, struct rdac_controller, ms_work);
 	struct scsi_device *sdev = ctlr->ms_sdev;
 	struct rdac_dh_data *h = sdev->handler_data;
-	int err = SCSI_DH_OK, retry_cnt = RDAC_RETRY_COUNT;
+	int err = SCSI_DH_OK;
 	struct rdac_queue_data *tmp, *qdata;
 	LIST_HEAD(list);
 	unsigned char cdb[MAX_COMMAND_SIZE];
@@ -538,8 +512,52 @@ static void send_mode_select(struct work_struct *work)
 	unsigned int data_size;
 	blk_opf_t opf = REQ_OP_DRV_OUT | REQ_FAILFAST_DEV |
 				REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER;
+	struct scsi_failure failures[] = {
+		{
+			.sense = NO_SENSE,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = RDAC_RETRY_COUNT,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = ABORTED_COMMAND,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = RDAC_RETRY_COUNT,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = RDAC_RETRY_COUNT,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			/*
+			 * LUN Not Ready and is in the Process of Becoming
+			 * Ready
+			 */
+			.sense = NOT_READY,
+			.asc = 0x04,
+			.ascq = 0x01,
+			.allowed = RDAC_RETRY_COUNT,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			/* Command Lock contention */
+			.sense = ILLEGAL_REQUEST,
+			.asc = 0x91,
+			.ascq = 0x36,
+			.allowed = SCMD_FAILURE_NO_LIMIT,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.sshdr = &sshdr,
+		.failures = failures,
 	};
 	int rc;
 
@@ -549,27 +567,19 @@ static void send_mode_select(struct work_struct *work)
 	ctlr->ms_sdev = NULL;
 	spin_unlock(&ctlr->ms_lock);
 
- retry:
 	memset(cdb, 0, sizeof(cdb));
 
 	data_size = rdac_failover_get(ctlr, &list, cdb);
 
-	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
-		"%s MODE_SELECT command",
-		(char *) h->ctlr->array_name, h->ctlr->index,
-		(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
+	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, MODE_SELECT command",
+		 (char *)h->ctlr->array_name, h->ctlr->index);
 
 	rc = scsi_execute_cmd(sdev, cdb, opf, &h->ctlr->mode_select, data_size,
 			      RDAC_TIMEOUT * HZ, RDAC_RETRIES, &exec_args);
-	if (rc < 0) {
+	if (rc < 0)
 		err = SCSI_DH_IO;
-	} else if (rc > 0) {
+	else if (rc > 0)
 		err = mode_select_handle_sense(sdev, &sshdr);
-		if (err == SCSI_DH_RETRY && retry_cnt--)
-			goto retry;
-		if (err == SCSI_DH_IMM_RETRY)
-			goto retry;
-	}
 
 	if (err == SCSI_DH_OK) {
 		h->state = RDAC_STATE_ACTIVE;
-- 
2.34.1

[PATCH v10 15/33] scsi: spi: Fix sshdr use

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi_transport_spi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_transport_spi.c b/drivers/scsi/scsi_transport_spi.c
index 2442d4d2e3f3..f668c1c0a98f 100644
--- a/drivers/scsi/scsi_transport_spi.c
+++ b/drivers/scsi/scsi_transport_spi.c
@@ -676,10 +676,10 @@ spi_dv_device_echo_buffer(struct scsi_device *sdev, u8 *buffer,
 	for (r = 0; r < retries; r++) {
 		result = spi_execute(sdev, spi_write_buffer, REQ_OP_DRV_OUT,
 				     buffer, len, &sshdr);
-		if(result || !scsi_device_online(sdev)) {
+		if (result || !scsi_device_online(sdev)) {
 
 			scsi_device_set_state(sdev, SDEV_QUIESCE);
-			if (scsi_sense_valid(&sshdr)
+			if (result > 0 && scsi_sense_valid(&sshdr)
 			    && sshdr.sense_key == ILLEGAL_REQUEST
 			    /* INVALID FIELD IN CDB */
 			    && sshdr.asc == 0x24 && sshdr.ascq == 0x00)
-- 
2.34.1

Re: [PATCH v10 15/33] scsi: spi: Fix sshdr use

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 16/33] scsi: spi: Have scsi-ml retry spi_execute errors

[Mike Christie]

This has spi_execute have scsi-ml retry errors instead of driving them.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi_transport_spi.c | 35 ++++++++++++++++---------------
 1 file changed, 18 insertions(+), 17 deletions(-)

diff --git a/drivers/scsi/scsi_transport_spi.c b/drivers/scsi/scsi_transport_spi.c
index f668c1c0a98f..b2f5c1d2b451 100644
--- a/drivers/scsi/scsi_transport_spi.c
+++ b/drivers/scsi/scsi_transport_spi.c
@@ -108,29 +108,30 @@ static int spi_execute(struct scsi_device *sdev, const void *cmd,
 		       enum req_op op, void *buffer, unsigned int bufflen,
 		       struct scsi_sense_hdr *sshdr)
 {
-	int i, result;
-	struct scsi_sense_hdr sshdr_tmp;
 	blk_opf_t opf = op | REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
 			REQ_FAILFAST_DRIVER;
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = DV_RETRIES,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.req_flags = BLK_MQ_REQ_PM,
-		.sshdr = sshdr ? : &sshdr_tmp,
+		.sshdr = sshdr,
+		.failures = failures,
 	};
 
-	sshdr = exec_args.sshdr;
-
-	for(i = 0; i < DV_RETRIES; i++) {
-		/*
-		 * The purpose of the RQF_PM flag below is to bypass the
-		 * SDEV_QUIESCE state.
-		 */
-		result = scsi_execute_cmd(sdev, cmd, opf, buffer, bufflen,
-					  DV_TIMEOUT, 1, &exec_args);
-		if (result < 0 || !scsi_sense_valid(sshdr) ||
-		    sshdr->sense_key != UNIT_ATTENTION)
-			break;
-	}
-	return result;
+	/*
+	 * The purpose of the RQF_PM flag below is to bypass the
+	 * SDEV_QUIESCE state.
+	 */
+	return scsi_execute_cmd(sdev, cmd, opf, buffer, bufflen, DV_TIMEOUT, 1,
+				&exec_args);
 }
 
 static struct {
-- 
2.34.1

Re: [PATCH v10 16/33] scsi: spi: Have scsi-ml retry spi_execute errors

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> This has spi_execute have scsi-ml retry errors instead of driving them.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Just a comment on a comment, below.
Reviewed-by: John Garry <john.g.garry@oracle.com>

> ---
>   drivers/scsi/scsi_transport_spi.c | 35 ++++++++++++++++---------------
>   1 file changed, 18 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/scsi/scsi_transport_spi.c b/drivers/scsi/scsi_transport_spi.c
> index f668c1c0a98f..b2f5c1d2b451 100644
> --- a/drivers/scsi/scsi_transport_spi.c
> +++ b/drivers/scsi/scsi_transport_spi.c
> @@ -108,29 +108,30 @@ static int spi_execute(struct scsi_device *sdev, const void *cmd, >   		       enum req_op op, void *buffer, unsigned int bufflen,
>   		       struct scsi_sense_hdr *sshdr)
>   {
> -	int i, result;
> -	struct scsi_sense_hdr sshdr_tmp;
>   	blk_opf_t opf = op | REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
>   			REQ_FAILFAST_DRIVER;
> +	struct scsi_failure failures[] = {
> +		{
> +			.sense = UNIT_ATTENTION,
> +			.asc = SCMD_FAILURE_ASC_ANY,
> +			.ascq = SCMD_FAILURE_ASCQ_ANY,
> +			.allowed = DV_RETRIES,
> +			.result = SAM_STAT_CHECK_CONDITION,
> +		},
> +		{}
> +	};
>   	const struct scsi_exec_args exec_args = {
>   		.req_flags = BLK_MQ_REQ_PM,
> -		.sshdr = sshdr ? : &sshdr_tmp,
> +		.sshdr = sshdr,
> +		.failures = failures,
>   	};
>   
> -	sshdr = exec_args.sshdr;
> -
> -	for(i = 0; i < DV_RETRIES; i++) {
> -		/*
> -		 * The purpose of the RQF_PM flag below is to bypass the
> -		 * SDEV_QUIESCE state.
> -		 */
> -		result = scsi_execute_cmd(sdev, cmd, opf, buffer, bufflen,
> -					  DV_TIMEOUT, 1, &exec_args);
> -		if (result < 0 || !scsi_sense_valid(sshdr) ||
> -		    sshdr->sense_key != UNIT_ATTENTION)
> -			break;
> -	}
> -	return result;
> +	/*
> +	 * The purpose of the RQF_PM flag below is to bypass the
> +	 * SDEV_QUIESCE state.
> +	 */

I guess that this comment has been misplaced since we switched to using 
scsi_exec_args

> +	return scsi_execute_cmd(sdev, cmd, opf, buffer, bufflen, DV_TIMEOUT, 1,
> +				&exec_args);

[PATCH v10 17/33] scsi: sd: Fix sshdr use in sd_suspend_common

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. To avoid where
sd_suspend_common will access the sshdr but scsi_execute_cmd has
not initialized it and to allow sd_sync_cache to convert
device/host/status errors to -EXYZ values, this has sd_sync_cache
convert ILLEGAL_REQUEST to -EOPNOTSUPP. sd_suspend_common can then
check for that error instead of using a sshdr.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 37 +++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 20 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 34a1149bfff2..1f110d646896 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1603,24 +1603,21 @@ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
 	return disk_changed ? DISK_EVENT_MEDIA_CHANGE : 0;
 }
 
-static int sd_sync_cache(struct scsi_disk *sdkp, struct scsi_sense_hdr *sshdr)
+static int sd_sync_cache(struct scsi_disk *sdkp)
 {
 	int retries, res;
 	struct scsi_device *sdp = sdkp->device;
 	const int timeout = sdp->request_queue->rq_timeout
 		* SD_FLUSH_TIMEOUT_MULTIPLIER;
-	struct scsi_sense_hdr my_sshdr;
+	struct scsi_sense_hdr sshdr;
 	const struct scsi_exec_args exec_args = {
 		.req_flags = BLK_MQ_REQ_PM,
-		/* caller might not be interested in sense, but we need it */
-		.sshdr = sshdr ? : &my_sshdr,
+		.sshdr = &sshdr,
 	};
 
 	if (!scsi_device_online(sdp))
 		return -ENODEV;
 
-	sshdr = exec_args.sshdr;
-
 	for (retries = 3; retries > 0; --retries) {
 		unsigned char cmd[16] = { 0 };
 
@@ -1645,15 +1642,19 @@ static int sd_sync_cache(struct scsi_disk *sdkp, struct scsi_sense_hdr *sshdr)
 			return res;
 
 		if (scsi_status_is_check_condition(res) &&
-		    scsi_sense_valid(sshdr)) {
-			sd_print_sense_hdr(sdkp, sshdr);
+		    scsi_sense_valid(&sshdr)) {
+			sd_print_sense_hdr(sdkp, &sshdr);
 
 			/* we need to evaluate the error return  */
-			if (sshdr->asc == 0x3a ||	/* medium not present */
-			    sshdr->asc == 0x20 ||	/* invalid command */
-			    (sshdr->asc == 0x74 && sshdr->ascq == 0x71))	/* drive is password locked */
+			if (sshdr.asc == 0x3a ||	/* medium not present */
+			    sshdr.asc == 0x20 ||	/* invalid command */
+			    (sshdr.asc == 0x74 && sshdr.ascq == 0x71))	/* drive is password locked */
 				/* this is no error here */
 				return 0;
+
+			/* This drive doesn't support sync. */
+			if (sshdr.sense_key == ILLEGAL_REQUEST)
+				return -EOPNOTSUPP;
 		}
 
 		switch (host_byte(res)) {
@@ -3848,7 +3849,7 @@ static void sd_shutdown(struct device *dev)
 
 	if (sdkp->WCE && sdkp->media_present) {
 		sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
-		sd_sync_cache(sdkp, NULL);
+		sd_sync_cache(sdkp);
 	}
 
 	if (system_state != SYSTEM_RESTART && sdkp->device->manage_start_stop) {
@@ -3860,7 +3861,6 @@ static void sd_shutdown(struct device *dev)
 static int sd_suspend_common(struct device *dev, bool ignore_stop_errors)
 {
 	struct scsi_disk *sdkp = dev_get_drvdata(dev);
-	struct scsi_sense_hdr sshdr;
 	int ret = 0;
 
 	if (!sdkp)	/* E.g.: runtime suspend following sd_remove() */
@@ -3869,21 +3869,18 @@ static int sd_suspend_common(struct device *dev, bool ignore_stop_errors)
 	if (sdkp->WCE && sdkp->media_present) {
 		if (!sdkp->device->silence_suspend)
 			sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
-		ret = sd_sync_cache(sdkp, &sshdr);
+		ret = sd_sync_cache(sdkp);
 
 		if (ret) {
 			/* ignore OFFLINE device */
 			if (ret == -ENODEV)
 				return 0;
 
-			if (!scsi_sense_valid(&sshdr) ||
-			    sshdr.sense_key != ILLEGAL_REQUEST)
+			if (ret != -EOPNOTSUPP)
 				return ret;
-
 			/*
-			 * sshdr.sense_key == ILLEGAL_REQUEST means this drive
-			 * doesn't support sync. There's not much to do and
-			 * suspend shouldn't fail.
+			 * The drive doesn't support sync. There's not much to
+			 * do and suspend shouldn't fail.
 			 */
 			ret = 0;
 		}
-- 
2.34.1

Re: [PATCH v10 17/33] scsi: sd: Fix sshdr use in sd_suspend_common

[John Garry]

> -
>   	for (retries = 3; retries > 0; --retries) {
>   		unsigned char cmd[16] = { 0 };
>   
> @@ -1645,15 +1642,19 @@ static int sd_sync_cache(struct scsi_disk *sdkp, struct scsi_sense_hdr *sshdr)
>   			return res;
>   
>   		if (scsi_status_is_check_condition(res) &&
> -		    scsi_sense_valid(sshdr)) {
> -			sd_print_sense_hdr(sdkp, sshdr);
> +		    scsi_sense_valid(&sshdr)) {
> +			sd_print_sense_hdr(sdkp, &sshdr);
>   
>   			/* we need to evaluate the error return  */
> -			if (sshdr->asc == 0x3a ||	/* medium not present */
> -			    sshdr->asc == 0x20 ||	/* invalid command */
> -			    (sshdr->asc == 0x74 && sshdr->ascq == 0x71))	/* drive is password locked */
> +			if (sshdr.asc == 0x3a ||	/* medium not present */
> +			    sshdr.asc == 0x20 ||	/* invalid command */
> +			    (sshdr.asc == 0x74 && sshdr.ascq == 0x71))	/* drive is password locked */
>   				/* this is no error here */
>   				return 0;
> +
> +			/* This drive doesn't support sync. */
> +			if (sshdr.sense_key == ILLEGAL_REQUEST)
> +				return -EOPNOTSUPP;

Only sd_suspend_common() interprets this, right? And in that case, it 
treats as if no error, so could you just return 0 here (and drop the 
-EOPNOTSUPP check in sd_suspend_common())?

Thanks,
John

>   		}
>   
>   		switch (host_byte(res)) {
> @@ -3848,7 +3849,7 @@ static void sd_shutdown(struct device *dev)
>   
>   	if (sdkp->WCE && sdkp->media_present) {
>   		sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
> -		sd_sync_cache(sdkp, NULL);
> +		sd_sync_cache(sdkp);
>   	}
>   
>   	if (system_state != SYSTEM_RESTART && sdkp->device->manage_start_stop) {
> @@ -3860,7 +3861,6 @@ static void sd_shutdown(struct device *dev)
>   static int sd_suspend_common(struct device *dev, bool ignore_stop_errors)
>   {
>   	struct scsi_disk *sdkp = dev_get_drvdata(dev);
> -	struct scsi_sense_hdr sshdr;
>   	int ret = 0;
>   
>   	if (!sdkp)	/* E.g.: runtime suspend following sd_remove() */
> @@ -3869,21 +3869,18 @@ static int sd_suspend_common(struct device *dev, bool ignore_stop_errors)
>   	if (sdkp->WCE && sdkp->media_present) {
>   		if (!sdkp->device->silence_suspend)
>   			sd_printk(KERN_NOTICE, sdkp, "Synchronizing SCSI cache\n");
> -		ret = sd_sync_cache(sdkp, &sshdr);
> +		ret = sd_sync_cache(sdkp);
>   
>   		if (ret) {
>   			/* ignore OFFLINE device */
>   			if (ret == -ENODEV)
>   				return 0;
>   
> -			if (!scsi_sense_valid(&sshdr) ||
> -			    sshdr.sense_key != ILLEGAL_REQUEST)
> +			if (ret != -EOPNOTSUPP)
>   				return ret;
> -
>   			/*
> -			 * sshdr.sense_key == ILLEGAL_REQUEST means this drive
> -			 * doesn't support sync. There's not much to do and
> -			 * suspend shouldn't fail.
> +			 * The drive doesn't support sync. There's not much to
> +			 * do and suspend shouldn't fail.
>   			 */
>   			ret = 0;
>   		}

[PATCH v10 18/33] scsi: sd: Have scsi-ml retry sd_sync_cache errors

[Mike Christie]

This has sd_sync_cache have scsi-ml retry errors instead of driving them
itself.

There is one behavior change where we no longer retry when
scsi_execute_cmd returns < 0, but we should be ok. We don't need to retry
for failures like the queue being removed, and for the case where there
are no tags/reqs the block layer waits/retries for us. For possible memory
allocation failures from blk_rq_map_kern we use GFP_NOIO, so retrying
will probably not help.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 32 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 1f110d646896..deac35fb520b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1605,36 +1605,32 @@ static unsigned int sd_check_events(struct gendisk *disk, unsigned int clearing)
 
 static int sd_sync_cache(struct scsi_disk *sdkp)
 {
-	int retries, res;
+	int res;
 	struct scsi_device *sdp = sdkp->device;
 	const int timeout = sdp->request_queue->rq_timeout
 		* SD_FLUSH_TIMEOUT_MULTIPLIER;
+	/* Leave the rest of the command zero to indicate flush everything. */
+	const unsigned char cmd[16] = { sdp->use_16_for_sync ?
+				SYNCHRONIZE_CACHE_16 : SYNCHRONIZE_CACHE };
 	struct scsi_sense_hdr sshdr;
+	struct scsi_failure failures[] = {
+		{
+			.allowed = 3,
+			.result = SCMD_FAILURE_RESULT_ANY,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.req_flags = BLK_MQ_REQ_PM,
 		.sshdr = &sshdr,
+		.failures = failures,
 	};
 
 	if (!scsi_device_online(sdp))
 		return -ENODEV;
 
-	for (retries = 3; retries > 0; --retries) {
-		unsigned char cmd[16] = { 0 };
-
-		if (sdp->use_16_for_sync)
-			cmd[0] = SYNCHRONIZE_CACHE_16;
-		else
-			cmd[0] = SYNCHRONIZE_CACHE;
-		/*
-		 * Leave the rest of the command zero to indicate
-		 * flush everything.
-		 */
-		res = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, NULL, 0,
-				       timeout, sdkp->max_retries, &exec_args);
-		if (res == 0)
-			break;
-	}
-
+	res = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, NULL, 0, timeout,
+			       sdkp->max_retries, &exec_args);
 	if (res) {
 		sd_print_result(sdkp, "Synchronize Cache(10) failed", res);
 
-- 
2.34.1

Re: [PATCH v10 18/33] scsi: sd: Have scsi-ml retry sd_sync_cache errors

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> This has sd_sync_cache have scsi-ml retry errors instead of driving them
> itself.
> 
> There is one behavior change where we no longer retry when
> scsi_execute_cmd returns < 0, but we should be ok. We don't need to retry
> for failures like the queue being removed, and for the case where there
> are no tags/reqs the block layer waits/retries for us. For possible memory
> allocation failures from blk_rq_map_kern we use GFP_NOIO, so retrying
> will probably not help.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 19/33] scsi: ch: Remove unit_attention

[Mike Christie]

unit_attention is not used so remove it.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/ch.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index cb0a399be1cc..1a998e45978e 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -113,7 +113,6 @@ typedef struct {
 	struct scsi_device  **dt;        /* ptrs to data transfer elements */
 	u_int               firsts[CH_TYPES];
 	u_int               counts[CH_TYPES];
-	u_int               unit_attention;
 	u_int		    voltags;
 	struct mutex	    lock;
 } scsi_changer;
@@ -208,7 +207,6 @@ ch_do_scsi(scsi_changer *ch, unsigned char *cmd, int cmd_len,
 
 		switch(sshdr.sense_key) {
 		case UNIT_ATTENTION:
-			ch->unit_attention = 1;
 			if (retries++ < 3)
 				goto retry;
 			break;
-- 
2.34.1

Re: [PATCH v10 19/33] scsi: ch: Remove unit_attention

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> unit_attention is not used so remove it.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 20/33] scsi: ch: Have scsi-ml retry ch_do_scsi errors

[Mike Christie]

This has ch_do_scsi have scsi-ml retry errors instead of driving them
itself.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/ch.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
index 1a998e45978e..8ea498e6eec2 100644
--- a/drivers/scsi/ch.c
+++ b/drivers/scsi/ch.c
@@ -185,16 +185,26 @@ static int
 ch_do_scsi(scsi_changer *ch, unsigned char *cmd, int cmd_len,
 	   void *buffer, unsigned int buflength, enum req_op op)
 {
-	int errno, retries = 0, timeout, result;
+	int errno, timeout, result;
 	struct scsi_sense_hdr sshdr;
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = 3,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.sshdr = &sshdr,
+		.failures = failures,
 	};
 
 	timeout = (cmd[0] == INITIALIZE_ELEMENT_STATUS)
 		? timeout_init : timeout_move;
 
- retry:
 	errno = 0;
 	result = scsi_execute_cmd(ch->device, cmd, op, buffer, buflength,
 				  timeout * HZ, MAX_RETRIES, &exec_args);
@@ -204,13 +214,6 @@ ch_do_scsi(scsi_changer *ch, unsigned char *cmd, int cmd_len,
 		if (debug)
 			scsi_print_sense_hdr(ch->device, ch->name, &sshdr);
 		errno = ch_find_errno(&sshdr);
-
-		switch(sshdr.sense_key) {
-		case UNIT_ATTENTION:
-			if (retries++ < 3)
-				goto retry;
-			break;
-		}
 	}
 	return errno;
 }
-- 
2.34.1

Re: [PATCH v10 20/33] scsi: ch: Have scsi-ml retry ch_do_scsi errors

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> This has ch_do_scsi have scsi-ml retry errors instead of driving them
> itself.
> 
> Signed-off-by: Mike Christie <michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Apart from a small comment, below:
Reviewed-by: John Garry <john.g.garry@oracle.com>

> ---
>   drivers/scsi/ch.c | 21 ++++++++++++---------
>   1 file changed, 12 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c
> index 1a998e45978e..8ea498e6eec2 100644
> --- a/drivers/scsi/ch.c
> +++ b/drivers/scsi/ch.c
> @@ -185,16 +185,26 @@ static int
>   ch_do_scsi(scsi_changer *ch, unsigned char *cmd, int cmd_len,
>   	   void *buffer, unsigned int buflength, enum req_op op)
>   {
> -	int errno, retries = 0, timeout, result;
> +	int errno, timeout, result;
>   	struct scsi_sense_hdr sshdr;
> +	struct scsi_failure failures[] = {
> +		{
> +			.sense = UNIT_ATTENTION,
> +			.asc = SCMD_FAILURE_ASC_ANY,
> +			.ascq = SCMD_FAILURE_ASCQ_ANY,
> +			.allowed = 3,
> +			.result = SAM_STAT_CHECK_CONDITION,
> +		},
> +		{}
> +	};
>   	const struct scsi_exec_args exec_args = {
>   		.sshdr = &sshdr,
> +		.failures = failures,
>   	};
>   
>   	timeout = (cmd[0] == INITIALIZE_ELEMENT_STATUS)
>   		? timeout_init : timeout_move;
>   
> - retry:
>   	errno = 0;

nit: can errno be init'ed to 0 when declared? Or in an 'else' part of 
the if (scsi_sense_valid()) check?

>   	result = scsi_execute_cmd(ch->device, cmd, op, buffer, buflength,
>   				  timeout * HZ, MAX_RETRIES, &exec_args);
> @@ -204,13 +214,6 @@ ch_do_scsi(scsi_changer *ch, unsigned char *cmd, int cmd_len,
>   		if (debug)
>   			scsi_print_sense_hdr(ch->device, ch->name, &sshdr);
>   		errno = ch_find_errno(&sshdr);
> -
> -		switch(sshdr.sense_key) {
> -		case UNIT_ATTENTION:
> -			if (retries++ < 3)
> -				goto retry;
> -			break;
> -		}
>   	}
>   	return errno;
>   }

[PATCH v10 21/33] scsi: Have scsi-ml retry scsi_mode_sense UAs

[Mike Christie]

This has scsi_mode_sense have scsi-ml retry UAs instead of driving them
itself.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi_lib.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0097166814a0..26b21e20ef0c 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2186,11 +2186,22 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage,
 	unsigned char cmd[12];
 	int use_10_for_ms;
 	int header_length;
-	int result, retry_count = retries;
+	int result;
 	struct scsi_sense_hdr my_sshdr;
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = retries,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		/* caller might not be interested in sense, but we need it */
 		.sshdr = sshdr ? : &my_sshdr,
+		.failures = failures,
 	};
 
 	memset(data, 0, sizeof(*data));
@@ -2252,12 +2263,6 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage,
 					goto retry;
 				}
 			}
-			if (scsi_status_is_check_condition(result) &&
-			    sshdr->sense_key == UNIT_ATTENTION &&
-			    retry_count) {
-				retry_count--;
-				goto retry;
-			}
 		}
 		return -EIO;
 	}
-- 
2.34.1

Re: [PATCH v10 21/33] scsi: Have scsi-ml retry scsi_mode_sense UAs

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> This has scsi_mode_sense have scsi-ml retry UAs instead of driving them
> itself.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

Re: [PATCH v10 21/33] scsi: Have scsi-ml retry scsi_mode_sense UAs

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> This has scsi_mode_sense have scsi-ml retry UAs instead of driving them
> itself.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 22/33] scsi: sd: Fix scsi_mode_sense caller's sshdr use

[Mike Christie]

The sshdr passed into scsi_execute_cmd is only initialized if
scsi_execute_cmd returns >= 0, and scsi_mode_sense will convert all non
good statuses like check conditions to -EIO. This has scsi_mode_sense
callers that were possibly accessing an uninitialized sshdrs to only
access it if we got -EIO.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index deac35fb520b..53719cf9d86e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2966,7 +2966,7 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
 	}
 
 bad_sense:
-	if (scsi_sense_valid(&sshdr) &&
+	if (res == -EIO && scsi_sense_valid(&sshdr) &&
 	    sshdr.sense_key == ILLEGAL_REQUEST &&
 	    sshdr.asc == 0x24 && sshdr.ascq == 0x0)
 		/* Invalid field in CDB */
@@ -3014,7 +3014,7 @@ static void sd_read_app_tag_own(struct scsi_disk *sdkp, unsigned char *buffer)
 		sd_first_printk(KERN_WARNING, sdkp,
 			  "getting Control mode page failed, assume no ATO\n");
 
-		if (scsi_sense_valid(&sshdr))
+		if (res == -EIO && scsi_sense_valid(&sshdr))
 			sd_print_sense_hdr(sdkp, &sshdr);
 
 		return;
-- 
2.34.1

Re: [PATCH v10 22/33] scsi: sd: Fix scsi_mode_sense caller's sshdr use

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> The sshdr passed into scsi_execute_cmd is only initialized if
> scsi_execute_cmd returns >= 0, and scsi_mode_sense will convert all non
> good statuses like check conditions to -EIO. This has scsi_mode_sense
> callers that were possibly accessing an uninitialized sshdrs to only
> access it if we got -EIO.
> 

sd_read_cache_type() -> sd_do_mode_sense() -> scsi_execute_cmd() may 
never return -EIO without getting as far as init'ing the sshdr, right?

> Signed-off-by: Mike Christie <michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/scsi/sd.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index deac35fb520b..53719cf9d86e 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -2966,7 +2966,7 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer)
>   	}
>   
>   bad_sense:
> -	if (scsi_sense_valid(&sshdr) &&
> +	if (res == -EIO && scsi_sense_valid(&sshdr) &&
>   	    sshdr.sense_key == ILLEGAL_REQUEST &&
>   	    sshdr.asc == 0x24 && sshdr.ascq == 0x0)
>   		/* Invalid field in CDB */
> @@ -3014,7 +3014,7 @@ static void sd_read_app_tag_own(struct scsi_disk *sdkp, unsigned char *buffer)
>   		sd_first_printk(KERN_WARNING, sdkp,
>   			  "getting Control mode page failed, assume no ATO\n");
>   
> -		if (scsi_sense_valid(&sshdr))
> +		if (res == -EIO && scsi_sense_valid(&sshdr))
>   			sd_print_sense_hdr(sdkp, &sshdr);
>   
>   		return;

Re: [PATCH v10 22/33] scsi: sd: Fix scsi_mode_sense caller's sshdr use

[michael.christie]

On 7/27/23 2:57 AM, John Garry wrote:
> On 14/07/2023 22:34, Mike Christie wrote:
>> The sshdr passed into scsi_execute_cmd is only initialized if
>> scsi_execute_cmd returns >= 0, and scsi_mode_sense will convert all non
>> good statuses like check conditions to -EIO. This has scsi_mode_sense
>> callers that were possibly accessing an uninitialized sshdrs to only
>> access it if we got -EIO.
>>
> 
> sd_read_cache_type() -> sd_do_mode_sense() -> scsi_execute_cmd() may never return -EIO without getting as far as init'ing the sshdr, right?
> 

Sorry for the late reply. I'm in and out of vacations.

That's correct.

[PATCH v10 23/33] scsi: Have scsi-ml retry scsi_report_lun_scan errors

[Mike Christie]

This has scsi_report_lun_scan have scsi-ml retry errors instead of driving
them itself.

There is one behavior change where we no longer retry when
scsi_execute_cmd returns < 0, but we should be ok. We don't need to retry
for failures like the queue being removed, and for the case where there
are no tags/reqs the block layer waits/retries for us. For possible memory
allocation failures from blk_rq_map_kern we use GFP_NOIO, so retrying
will probably not help.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi_scan.c | 56 +++++++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index e3c8edb92164..87c64b51465f 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1412,14 +1412,33 @@ static int scsi_report_lun_scan(struct scsi_target *starget, blist_flags_t bflag
 	unsigned int length;
 	u64 lun;
 	unsigned int num_luns;
-	unsigned int retries;
 	int result;
 	struct scsi_lun *lunp, *lun_data;
-	struct scsi_sense_hdr sshdr;
 	struct scsi_device *sdev;
 	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = 3,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		/* Fail all CCs except the UA above */
+		{
+			.sense = SCMD_FAILURE_SENSE_ANY,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		/* Retry any oher errors not listed above */
+		{
+			.result = SCMD_FAILURE_RESULT_ANY,
+			.allowed = 3,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
-		.sshdr = &sshdr,
+		.failures = failures,
 	};
 	int ret = 0;
 
@@ -1490,29 +1509,18 @@ static int scsi_report_lun_scan(struct scsi_target *starget, blist_flags_t bflag
 	 * should come through as a check condition, and will not generate
 	 * a retry.
 	 */
-	for (retries = 0; retries < 3; retries++) {
-		SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
-				"scsi scan: Sending REPORT LUNS to (try %d)\n",
-				retries));
-
-		result = scsi_execute_cmd(sdev, scsi_cmd, REQ_OP_DRV_IN,
-					  lun_data, length,
-					  SCSI_REPORT_LUNS_TIMEOUT, 3,
-					  &exec_args);
+	scsi_reset_failures(failures);
 
-		SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
-				"scsi scan: REPORT LUNS"
-				" %s (try %d) result 0x%x\n",
-				result ?  "failed" : "successful",
-				retries, result));
-		if (result == 0)
-			break;
-		else if (scsi_sense_valid(&sshdr)) {
-			if (sshdr.sense_key != UNIT_ATTENTION)
-				break;
-		}
-	}
+	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
+			  "scsi scan: Sending REPORT LUNS\n"));
+
+	result = scsi_execute_cmd(sdev, scsi_cmd, REQ_OP_DRV_IN, lun_data,
+				  length, SCSI_REPORT_LUNS_TIMEOUT, 3,
+				  &exec_args);
 
+	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
+			  "scsi scan: REPORT LUNS  %s result 0x%x\n",
+			  result ?  "failed" : "successful", result));
 	if (result) {
 		/*
 		 * The device probably does not support a REPORT LUN command
-- 
2.34.1

Re: [PATCH v10 23/33] scsi: Have scsi-ml retry scsi_report_lun_scan errors

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> This has scsi_report_lun_scan have scsi-ml retry errors instead of driving
> them itself.
> 
> There is one behavior change where we no longer retry when
> scsi_execute_cmd returns < 0, but we should be ok. We don't need to retry
> for failures like the queue being removed, and for the case where there
> are no tags/reqs the block layer waits/retries for us. For possible memory
> allocation failures from blk_rq_map_kern we use GFP_NOIO, so retrying
> will probably not help.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>
> ---

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 24/33] scsi: sd: Have pr commands retry UAs

[Mike Christie]

It's common to get a UA when doing PR commands. It could be due to a
target restarting, transport level relogin or other PR commands like a
release causing it. The upper layers don't get the sense and in some cases
have no idea if it's a SCSI device, so this has the sd layer retry.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 53719cf9d86e..c4de2f959393 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1753,8 +1753,19 @@ static int sd_pr_in_command(struct block_device *bdev, u8 sa,
 	struct scsi_device *sdev = sdkp->device;
 	struct scsi_sense_hdr sshdr;
 	u8 cmd[10] = { PERSISTENT_RESERVE_IN, sa };
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = 5,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.sshdr = &sshdr,
+		.failures = failures,
 	};
 	int result;
 
@@ -1841,8 +1852,19 @@ static int sd_pr_out_command(struct block_device *bdev, u8 sa, u64 key,
 	struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
 	struct scsi_device *sdev = sdkp->device;
 	struct scsi_sense_hdr sshdr;
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = 5,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.sshdr = &sshdr,
+		.failures = failures,
 	};
 	int result;
 	u8 cmd[16] = { 0, };
-- 
2.34.1

[PATCH v10 25/33] scsi: sd: Have scsi-ml retry read_capacity_10 errors

[Mike Christie]

This has read_capacity_10 have scsi-ml retry errors instead of driving
them itself.

There are two behavior changes:
1. We no longer retry when scsi_execute_cmd returns < 0, but we should be
ok. We don't need to retry for failures like the queue being removed, and
for the case where there are no tags/reqs the block layer waits/retries
for us. For possible memory allocation failures from blk_rq_map_kern we
use GFP_NOIO, so retrying will probably not help.
2. For device reset UAs, we would retry READ_CAPACITY_RETRIES_ON_RESET
times, then once those are used up we would hit the main do loops retry
counter and get 3 more retries. We now only get
READ_CAPACITY_RETRIES_ON_RESET retries.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 64 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 41 insertions(+), 23 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index c4de2f959393..34fb0f8d189e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2556,42 +2556,60 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
 static int read_capacity_10(struct scsi_disk *sdkp, struct scsi_device *sdp,
 						unsigned char *buffer)
 {
-	unsigned char cmd[16];
+	static const u8 cmd[10] = { READ_CAPACITY };
 	struct scsi_sense_hdr sshdr;
+	struct scsi_failure failures[] = {
+		/* Fail immediately for Medium Not Present */
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x3A,
+			.ascq = 0x0,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = NOT_READY,
+			.asc = 0x3A,
+			.ascq = 0x0,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x29,
+			.ascq = 0,
+			/* Device reset might occur several times */
+			.allowed = READ_CAPACITY_RETRIES_ON_RESET,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		/* Any other error not listed above retry */
+		{
+			.result = SCMD_FAILURE_RESULT_ANY,
+			.allowed = 3,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
 		.sshdr = &sshdr,
+		.failures = failures,
 	};
 	int sense_valid = 0;
 	int the_result;
-	int retries = 3, reset_retries = READ_CAPACITY_RETRIES_ON_RESET;
 	sector_t lba;
 	unsigned sector_size;
 
-	do {
-		cmd[0] = READ_CAPACITY;
-		memset(&cmd[1], 0, 9);
-		memset(buffer, 0, 8);
+	memset(buffer, 0, 8);
 
-		the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, buffer,
-					      8, SD_TIMEOUT, sdkp->max_retries,
-					      &exec_args);
+	the_result = scsi_execute_cmd(sdp, cmd, REQ_OP_DRV_IN, buffer,
+				      8, SD_TIMEOUT, sdkp->max_retries,
+				      &exec_args);
+
+	if (the_result > 0) {
+		sense_valid = scsi_sense_valid(&sshdr);
 
 		if (media_not_present(sdkp, &sshdr))
 			return -ENODEV;
-
-		if (the_result > 0) {
-			sense_valid = scsi_sense_valid(&sshdr);
-			if (sense_valid &&
-			    sshdr.sense_key == UNIT_ATTENTION &&
-			    sshdr.asc == 0x29 && sshdr.ascq == 0x00)
-				/* Device reset might occur several times,
-				 * give it one more chance */
-				if (--reset_retries > 0)
-					continue;
-		}
-		retries--;
-
-	} while (the_result && retries);
+	}
 
 	if (the_result) {
 		sd_print_result(sdkp, "Read Capacity(10) failed", the_result);
-- 
2.34.1

[PATCH v10 26/33] scsi: ses: Have scsi-ml retry scsi_exec_req errors

[Mike Christie]

This has ses have scsi-ml retry scsi_exec_req errors instead of driving
them itself.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/ses.c | 60 ++++++++++++++++++++++++++++++----------------
 1 file changed, 40 insertions(+), 20 deletions(-)

diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c
index d7d0c35c58b8..f3d497366af1 100644
--- a/drivers/scsi/ses.c
+++ b/drivers/scsi/ses.c
@@ -87,19 +87,29 @@ static int ses_recv_diag(struct scsi_device *sdev, int page_code,
 		0
 	};
 	unsigned char recv_page_code;
-	unsigned int retries = SES_RETRIES;
-	struct scsi_sense_hdr sshdr;
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x29,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = SES_RETRIES,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = NOT_READY,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = SES_RETRIES,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
-		.sshdr = &sshdr,
+		.failures = failures,
 	};
 
-	do {
-		ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buf, bufflen,
-				       SES_TIMEOUT, 1, &exec_args);
-	} while (ret > 0 && --retries && scsi_sense_valid(&sshdr) &&
-		 (sshdr.sense_key == NOT_READY ||
-		  (sshdr.sense_key == UNIT_ATTENTION && sshdr.asc == 0x29)));
-
+	ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buf, bufflen,
+			       SES_TIMEOUT, 1, &exec_args);
 	if (unlikely(ret))
 		return ret;
 
@@ -131,19 +141,29 @@ static int ses_send_diag(struct scsi_device *sdev, int page_code,
 		bufflen & 0xff,
 		0
 	};
-	struct scsi_sense_hdr sshdr;
-	unsigned int retries = SES_RETRIES;
+	struct scsi_failure failures[] = {
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x29,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = SES_RETRIES,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = NOT_READY,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = SES_RETRIES,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
 	const struct scsi_exec_args exec_args = {
-		.sshdr = &sshdr,
+		.failures = failures,
 	};
 
-	do {
-		result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, buf,
-					  bufflen, SES_TIMEOUT, 1, &exec_args);
-	} while (result > 0 && --retries && scsi_sense_valid(&sshdr) &&
-		 (sshdr.sense_key == NOT_READY ||
-		  (sshdr.sense_key == UNIT_ATTENTION && sshdr.asc == 0x29)));
-
+	result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, buf, bufflen,
+				  SES_TIMEOUT, 1, &exec_args);
 	if (result)
 		sdev_printk(KERN_ERR, sdev, "SEND DIAGNOSTIC result: %8x\n",
 			    result);
-- 
2.34.1

[PATCH v10 27/33] scsi: sr: Have scsi-ml retry get_sectorsize errors

[Mike Christie]

This has get_sectorsize have scsi-ml retry errors instead of driving them
itself.

There is one behavior change where we no longer retry when
scsi_execute_cmd returns < 0, but we should be ok. We don't need to retry
for failures like the queue being removed, and for the case where there
are no tags/reqs the block layer waits/retries for us. For possible memory
allocation failures from blk_rq_map_kern we use GFP_NOIO, so retrying
will probably not help.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sr.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 07ef3db3d1a1..100480f5bc2c 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -716,27 +716,26 @@ static int sr_probe(struct device *dev)
 
 static void get_sectorsize(struct scsi_cd *cd)
 {
-	unsigned char cmd[10];
-	unsigned char buffer[8];
-	int the_result, retries = 3;
+	static const u8 cmd[10] = { READ_CAPACITY };
+	unsigned char buffer[8] = { };
+	int the_result;
 	int sector_size;
 	struct request_queue *queue;
+	struct scsi_failure failures[] = {
+		{
+			.result = SCMD_FAILURE_RESULT_ANY,
+			.allowed = 3,
+		},
+		{}
+	};
+	const struct scsi_exec_args exec_args = {
+		.failures = failures,
+	};
 
-	do {
-		cmd[0] = READ_CAPACITY;
-		memset((void *) &cmd[1], 0, 9);
-		memset(buffer, 0, sizeof(buffer));
-
-		/* Do the command and wait.. */
-		the_result = scsi_execute_cmd(cd->device, cmd, REQ_OP_DRV_IN,
-					      buffer, sizeof(buffer),
-					      SR_TIMEOUT, MAX_RETRIES, NULL);
-
-		retries--;
-
-	} while (the_result && retries);
-
-
+	/* Do the command and wait.. */
+	the_result = scsi_execute_cmd(cd->device, cmd, REQ_OP_DRV_IN, buffer,
+				      sizeof(buffer), SR_TIMEOUT, MAX_RETRIES,
+				      &exec_args);
 	if (the_result) {
 		cd->capacity = 0x1fffff;
 		sector_size = 2048;	/* A guess, just in case */
-- 
2.34.1

[PATCH v10 28/33] scsi: ufs: Have scsi-ml retry start stop errors

[Mike Christie]

This has scsi-ml retry errors instead of driving them itself.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/ufs/core/ufshcd.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 983fae84d9e8..267c24c57396 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -9291,7 +9291,14 @@ static int ufshcd_execute_start_stop(struct scsi_device *sdev,
 				     struct scsi_sense_hdr *sshdr)
 {
 	const unsigned char cdb[6] = { START_STOP, 0, 0, 0, pwr_mode << 4, 0 };
+	struct scsi_failure failures[] = {
+		{
+			.allowed = 2,
+			.result = SCMD_FAILURE_RESULT_ANY,
+		},
+	};
 	const struct scsi_exec_args args = {
+		.failures = failures,
 		.sshdr = sshdr,
 		.req_flags = BLK_MQ_REQ_PM,
 		.scmd_flags = SCMD_FAIL_IF_RECOVERING,
@@ -9317,7 +9324,7 @@ static int ufshcd_set_dev_pwr_mode(struct ufs_hba *hba,
 	struct scsi_sense_hdr sshdr;
 	struct scsi_device *sdp;
 	unsigned long flags;
-	int ret, retries;
+	int ret;
 
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	sdp = hba->ufs_device_wlun;
@@ -9343,15 +9350,7 @@ static int ufshcd_set_dev_pwr_mode(struct ufs_hba *hba,
 	 * callbacks hence set the RQF_PM flag so that it doesn't resume the
 	 * already suspended childs.
 	 */
-	for (retries = 3; retries > 0; --retries) {
-		ret = ufshcd_execute_start_stop(sdp, pwr_mode, &sshdr);
-		/*
-		 * scsi_execute() only returns a negative value if the request
-		 * queue is dying.
-		 */
-		if (ret <= 0)
-			break;
-	}
+	ret = ufshcd_execute_start_stop(sdp, pwr_mode, &sshdr);
 	if (ret) {
 		sdev_printk(KERN_WARNING, sdp,
 			    "START_STOP failed for power mode: %d, result %x\n",
-- 
2.34.1

Re: [PATCH v10 28/33] scsi: ufs: Have scsi-ml retry start stop errors

[Bart Van Assche]

On 7/14/23 14:34, Mike Christie wrote:
> This has scsi-ml retry errors instead of driving them itself.
> 
> Signed-off-by: Mike Christie <michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/ufs/core/ufshcd.c | 19 +++++++++----------
>   1 file changed, 9 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 983fae84d9e8..267c24c57396 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -9291,7 +9291,14 @@ static int ufshcd_execute_start_stop(struct scsi_device *sdev,
>   				     struct scsi_sense_hdr *sshdr)
>   {
>   	const unsigned char cdb[6] = { START_STOP, 0, 0, 0, pwr_mode << 4, 0 };
> +	struct scsi_failure failures[] = {
> +		{
> +			.allowed = 2,
> +			.result = SCMD_FAILURE_RESULT_ANY,
> +		},
> +	};
>   	const struct scsi_exec_args args = {
> +		.failures = failures,
>   		.sshdr = sshdr,
>   		.req_flags = BLK_MQ_REQ_PM,
>   		.scmd_flags = SCMD_FAIL_IF_RECOVERING,
> @@ -9317,7 +9324,7 @@ static int ufshcd_set_dev_pwr_mode(struct ufs_hba *hba,
>   	struct scsi_sense_hdr sshdr;
>   	struct scsi_device *sdp;
>   	unsigned long flags;
> -	int ret, retries;
> +	int ret;
>   
>   	spin_lock_irqsave(hba->host->host_lock, flags);
>   	sdp = hba->ufs_device_wlun;
> @@ -9343,15 +9350,7 @@ static int ufshcd_set_dev_pwr_mode(struct ufs_hba *hba,
>   	 * callbacks hence set the RQF_PM flag so that it doesn't resume the
>   	 * already suspended childs.
>   	 */
> -	for (retries = 3; retries > 0; --retries) {
> -		ret = ufshcd_execute_start_stop(sdp, pwr_mode, &sshdr);
> -		/*
> -		 * scsi_execute() only returns a negative value if the request
> -		 * queue is dying.
> -		 */
> -		if (ret <= 0)
> -			break;
> -	}
> +	ret = ufshcd_execute_start_stop(sdp, pwr_mode, &sshdr);
>   	if (ret) {
>   		sdev_printk(KERN_WARNING, sdp,
>   			    "START_STOP failed for power mode: %d, result %x\n",

The original code only retries if ->result > 0. Is my understanding 
correct that the new code retries SCSI command execution whether 
->result is < 0 or > 0? If so, I think this patch introduces an 
unintended behavior change.

Thanks,

Bart.

Re: [PATCH v10 28/33] scsi: ufs: Have scsi-ml retry start stop errors

[Mike Christie]

On 7/17/23 12:05 PM, Bart Van Assche wrote:
> On 7/14/23 14:34, Mike Christie wrote:
>> This has scsi-ml retry errors instead of driving them itself.
>>
>> Signed-off-by: Mike Christie <michael.christie@oracle.com>
>> Reviewed-by: Christoph Hellwig <hch@lst.de>
>> ---
>>   drivers/ufs/core/ufshcd.c | 19 +++++++++----------
>>   1 file changed, 9 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
>> index 983fae84d9e8..267c24c57396 100644
>> --- a/drivers/ufs/core/ufshcd.c
>> +++ b/drivers/ufs/core/ufshcd.c
>> @@ -9291,7 +9291,14 @@ static int ufshcd_execute_start_stop(struct scsi_device *sdev,
>>                        struct scsi_sense_hdr *sshdr)
>>   {
>>       const unsigned char cdb[6] = { START_STOP, 0, 0, 0, pwr_mode << 4, 0 };
>> +    struct scsi_failure failures[] = {
>> +        {
>> +            .allowed = 2,
>> +            .result = SCMD_FAILURE_RESULT_ANY,
>> +        },
>> +    };
>>       const struct scsi_exec_args args = {
>> +        .failures = failures,
>>           .sshdr = sshdr,
>>           .req_flags = BLK_MQ_REQ_PM,
>>           .scmd_flags = SCMD_FAIL_IF_RECOVERING,
>> @@ -9317,7 +9324,7 @@ static int ufshcd_set_dev_pwr_mode(struct ufs_hba *hba,
>>       struct scsi_sense_hdr sshdr;
>>       struct scsi_device *sdp;
>>       unsigned long flags;
>> -    int ret, retries;
>> +    int ret;
>>         spin_lock_irqsave(hba->host->host_lock, flags);
>>       sdp = hba->ufs_device_wlun;
>> @@ -9343,15 +9350,7 @@ static int ufshcd_set_dev_pwr_mode(struct ufs_hba *hba,
>>        * callbacks hence set the RQF_PM flag so that it doesn't resume the
>>        * already suspended childs.
>>        */
>> -    for (retries = 3; retries > 0; --retries) {
>> -        ret = ufshcd_execute_start_stop(sdp, pwr_mode, &sshdr);
>> -        /*
>> -         * scsi_execute() only returns a negative value if the request
>> -         * queue is dying.
>> -         */
>> -        if (ret <= 0)
>> -            break;
>> -    }
>> +    ret = ufshcd_execute_start_stop(sdp, pwr_mode, &sshdr);
>>       if (ret) {
>>           sdev_printk(KERN_WARNING, sdp,
>>                   "START_STOP failed for power mode: %d, result %x\n",
> 
> The original code only retries if ->result > 0. Is my understanding correct that the new code retries SCSI command execution whether ->result is < 0 or > 0? If so, I think this patch introduces an unintended behavior change.

The new code does not retry when result is < 0.

SCMD_FAILURE_RESULT_ANY is for cases where result > 0.

Re: [PATCH v10 28/33] scsi: ufs: Have scsi-ml retry start stop errors

[Bart Van Assche]

On 7/17/23 11:29, Mike Christie wrote:
> On 7/17/23 12:05 PM, Bart Van Assche wrote:
>> The original code only retries if ->result > 0. Is my understanding
>> correct that the new code retries SCSI command execution whether
>> ->result is < 0 or > 0? If so, I think this patch introduces an
>> unintended behavior change.
> 
> The new code does not retry when result is < 0.
> 
> SCMD_FAILURE_RESULT_ANY is for cases where result > 0.

Right. Hence:

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

[PATCH v10 29/33] scsi: Fix sshdr use in scsi_test_unit_ready

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi_lib.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 26b21e20ef0c..393cc4fd87b7 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2319,10 +2319,10 @@ scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
 	do {
 		result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0,
 					  timeout, 1, &exec_args);
-		if (sdev->removable && scsi_sense_valid(sshdr) &&
+		if (sdev->removable && result > 0 && scsi_sense_valid(sshdr) &&
 		    sshdr->sense_key == UNIT_ATTENTION)
 			sdev->changed = 1;
-	} while (scsi_sense_valid(sshdr) &&
+	} while (result > 0 && scsi_sense_valid(sshdr) &&
 		 sshdr->sense_key == UNIT_ATTENTION && --retries);
 
 	return result;
-- 
2.34.1

Re: [PATCH v10 29/33] scsi: Fix sshdr use in scsi_test_unit_ready

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 30/33] scsi: Fix sshdr use in scsi_cdl_enable

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index d0911bc28663..d1c0ba3ef1f5 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -692,7 +692,7 @@ int scsi_cdl_enable(struct scsi_device *sdev, bool enable)
 		ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3,
 				       &data, &sshdr);
 		if (ret) {
-			if (scsi_sense_valid(&sshdr))
+			if (ret > 0 && scsi_sense_valid(&sshdr))
 				scsi_print_sense_hdr(sdev,
 					dev_name(&sdev->sdev_gendev), &sshdr);
 			return ret;
-- 
2.34.1

Re: [PATCH v10 30/33] scsi: Fix sshdr use in scsi_cdl_enable

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 31/33] scsi: sd: Fix sshdr use in cache_type_store

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 34fb0f8d189e..da7afeecbf17 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -155,7 +155,7 @@ cache_type_store(struct device *dev, struct device_attribute *attr,
 	struct scsi_mode_data data;
 	struct scsi_sense_hdr sshdr;
 	static const char temp[] = "temporary ";
-	int len;
+	int len, ret;
 
 	if (sdp->type != TYPE_DISK && sdp->type != TYPE_ZBC)
 		/* no cache control on RBC devices; theoretically they
@@ -202,9 +202,10 @@ cache_type_store(struct device *dev, struct device_attribute *attr,
 	 */
 	data.device_specific = 0;
 
-	if (scsi_mode_select(sdp, 1, sp, buffer_data, len, SD_TIMEOUT,
-			     sdkp->max_retries, &data, &sshdr)) {
-		if (scsi_sense_valid(&sshdr))
+	ret = scsi_mode_select(sdp, 1, sp, buffer_data, len, SD_TIMEOUT,
+			       sdkp->max_retries, &data, &sshdr);
+	if (ret) {
+		if (ret > 0 && scsi_sense_valid(&sshdr))
 			sd_print_sense_hdr(sdkp, &sshdr);
 		return -EINVAL;
 	}
-- 
2.34.1

Re: [PATCH v10 31/33] scsi: sd: Fix sshdr use in cache_type_store

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>
> ---

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 32/33] scsi: sr: Fix sshdr use in sr_get_events

[Mike Christie]

If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
shouldn't access the sshdr. If it returns 0, then the cmd executed
successfully, so there is no need to check the sshdr. This has us access
the sshdr when get a return value > 0.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sr.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 100480f5bc2c..a1889709c84c 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -177,7 +177,8 @@ static unsigned int sr_get_events(struct scsi_device *sdev)
 
 	result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buf, sizeof(buf),
 				  SR_TIMEOUT, MAX_RETRIES, &exec_args);
-	if (scsi_sense_valid(&sshdr) && sshdr.sense_key == UNIT_ATTENTION)
+	if (result > 0 && scsi_sense_valid(&sshdr) &&
+	    sshdr.sense_key == UNIT_ATTENTION)
 		return DISK_EVENT_MEDIA_CHANGE;
 
 	if (result || be16_to_cpu(eh->data_len) < sizeof(*med))
-- 
2.34.1

Re: [PATCH v10 32/33] scsi: sr: Fix sshdr use in sr_get_events

[John Garry]

On 14/07/2023 22:34, Mike Christie wrote:
> If scsi_execute_cmd returns < 0, it doesn't initialize the sshdr, so we
> shouldn't access the sshdr. If it returns 0, then the cmd executed
> successfully, so there is no need to check the sshdr. This has us access
> the sshdr when get a return value > 0.
> 
> Signed-off-by: Mike Christie<michael.christie@oracle.com>
> Reviewed-by: Christoph Hellwig<hch@lst.de>

Reviewed-by: John Garry <john.g.garry@oracle.com>

[PATCH v10 33/33] scsi: Add kunit tests for scsi_check_passthrough

[Mike Christie]

Add some kunit tests for scsi_check_passthrough so we can easily make sure
we are hitting the cases it's difficult to replicate in hardware or even
scsi_debug.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/Kconfig           |   9 ++
 drivers/scsi/scsi_error.c      |   4 +
 drivers/scsi/scsi_error_test.c | 170 +++++++++++++++++++++++++++++++++
 3 files changed, 183 insertions(+)
 create mode 100644 drivers/scsi/scsi_error_test.c

diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index 4962ce989113..be9b6eb2fba2 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -67,6 +67,15 @@ config SCSI_PROC_FS
 
 	  If unsure say Y.
 
+config SCSI_KUNIT_TEST
+	tristate "KUnit tests for SCSI Mid Layer" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Run SCSI Mid Layer's KUnit tests.
+
+	  If unsure say N.
+
 comment "SCSI support type (disk, tape, CD-ROM)"
 	depends on SCSI
 
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index d2fb28212880..f12ab199a03f 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -2663,3 +2663,7 @@ bool scsi_get_sense_info_fld(const u8 *sense_buffer, int sb_len,
 	}
 }
 EXPORT_SYMBOL(scsi_get_sense_info_fld);
+
+#ifdef CONFIG_SCSI_KUNIT_TEST
+#include "scsi_error_test.c"
+#endif
diff --git a/drivers/scsi/scsi_error_test.c b/drivers/scsi/scsi_error_test.c
new file mode 100644
index 000000000000..c01201ad8702
--- /dev/null
+++ b/drivers/scsi/scsi_error_test.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit tests for scsi_error.c.
+ *
+ * Copyright (C) 2022, Oracle Corporation
+ */
+#include <kunit/test.h>
+
+#include <scsi/scsi_proto.h>
+#include <scsi/scsi_cmnd.h>
+
+#define SCSI_TEST_ERROR_MAX_ALLOWED 3
+
+static void scsi_test_error_check_passthough(struct kunit *test)
+{
+	struct scsi_failure multiple_sense_failures[] = {
+		{
+			.sense = DATA_PROTECT,
+			.asc = 0x1,
+			.ascq = 0x1,
+			.allowed = 0,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = UNIT_ATTENTION,
+			.asc = 0x11,
+			.ascq = 0x0,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = NOT_READY,
+			.asc = 0x11,
+			.ascq = 0x22,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = ABORTED_COMMAND,
+			.asc = 0x11,
+			.ascq = SCMD_FAILURE_ASCQ_ANY,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = HARDWARE_ERROR,
+			.asc = SCMD_FAILURE_ASC_ANY,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{
+			.sense = ILLEGAL_REQUEST,
+			.asc = 0x91,
+			.ascq = 0x36,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+			.result = SAM_STAT_CHECK_CONDITION,
+		},
+		{}
+	};
+	struct scsi_failure retryable_host_failures[] = {
+		{
+			.result = DID_TRANSPORT_DISRUPTED << 16,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+		},
+		{
+			.result = DID_TIME_OUT << 16,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+		},
+		{}
+	};
+	struct scsi_failure any_status_failures[] = {
+		{
+			.result = SCMD_FAILURE_STAT_ANY,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+		},
+		{}
+	};
+	struct scsi_failure any_sense_failures[] = {
+		{
+			.result = SCMD_FAILURE_SENSE_ANY,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+		},
+		{}
+	};
+	struct scsi_failure any_failures[] = {
+		{
+			.result = SCMD_FAILURE_RESULT_ANY,
+			.allowed = SCSI_TEST_ERROR_MAX_ALLOWED,
+		},
+		{}
+	};
+	u8 sense[SCSI_SENSE_BUFFERSIZE] = {};
+	struct scsi_cmnd sc = {
+		.sense_buffer = sense,
+		.failures = multiple_sense_failures,
+	};
+	int i;
+
+	/* Match end of array */
+	scsi_build_sense(&sc, 0, ILLEGAL_REQUEST, 0x91, 0x36);
+	KUNIT_EXPECT_EQ(test, NEEDS_RETRY, scsi_check_passthrough(&sc));
+	/* Basic match in array */
+	scsi_build_sense(&sc, 0, UNIT_ATTENTION, 0x11, 0x0);
+	KUNIT_EXPECT_EQ(test, NEEDS_RETRY, scsi_check_passthrough(&sc));
+	/* No matching sense entry */
+	scsi_build_sense(&sc, 0, MISCOMPARE, 0x11, 0x11);
+	KUNIT_EXPECT_EQ(test, SCSI_RETURN_NOT_HANDLED,
+			scsi_check_passthrough(&sc));
+	/* Match using SCMD_FAILURE_ASCQ_ANY */
+	scsi_build_sense(&sc, 0, ABORTED_COMMAND, 0x22, 0x22);
+	KUNIT_EXPECT_EQ(test, SCSI_RETURN_NOT_HANDLED,
+			scsi_check_passthrough(&sc));
+	/* Match using SCMD_FAILURE_ASC_ANY */
+	scsi_build_sense(&sc, 0, HARDWARE_ERROR, 0x11, 0x22);
+	KUNIT_EXPECT_EQ(test, NEEDS_RETRY, scsi_check_passthrough(&sc));
+	/* No matching status entry */
+	sc.result = SAM_STAT_RESERVATION_CONFLICT;
+	KUNIT_EXPECT_EQ(test, SCSI_RETURN_NOT_HANDLED,
+			scsi_check_passthrough(&sc));
+
+	/* Test hitting allowed limit */
+	scsi_build_sense(&sc, 0, NOT_READY, 0x11, 0x22);
+	for (i = 0; i < SCSI_TEST_ERROR_MAX_ALLOWED; i++)
+		KUNIT_EXPECT_EQ(test, NEEDS_RETRY, scsi_check_passthrough(&sc));
+	KUNIT_EXPECT_EQ(test, SUCCESS, scsi_check_passthrough(&sc));
+
+	/* Match using SCMD_FAILURE_SENSE_ANY */
+	sc.failures = any_sense_failures;
+	scsi_build_sense(&sc, 0, MEDIUM_ERROR, 0x11, 0x22);
+	KUNIT_EXPECT_EQ(test, NEEDS_RETRY, scsi_check_passthrough(&sc));
+
+	/* reset retries so we can retest */
+	scsi_reset_failures(multiple_sense_failures);
+
+	/* Test no retries allowed */
+	sc.failures = multiple_sense_failures;
+	scsi_build_sense(&sc, 0, DATA_PROTECT, 0x1, 0x1);
+	KUNIT_EXPECT_EQ(test, SUCCESS, scsi_check_passthrough(&sc));
+
+	/* No matching host byte entry */
+	sc.failures = retryable_host_failures;
+	sc.result = DID_NO_CONNECT << 16;
+	KUNIT_EXPECT_EQ(test, SCSI_RETURN_NOT_HANDLED,
+			scsi_check_passthrough(&sc));
+	/* Matching host byte entry */
+	sc.result = DID_TIME_OUT << 16;
+	KUNIT_EXPECT_EQ(test, NEEDS_RETRY, scsi_check_passthrough(&sc));
+
+	/* Match SCMD_FAILURE_RESULT_ANY */
+	sc.failures = any_failures;
+	sc.result = DID_TRANSPORT_FAILFAST << 16;
+	KUNIT_EXPECT_EQ(test, NEEDS_RETRY, scsi_check_passthrough(&sc));
+
+	/* Test any status handling */
+	sc.failures = any_status_failures;
+	sc.result = SAM_STAT_RESERVATION_CONFLICT;
+	KUNIT_EXPECT_EQ(test, NEEDS_RETRY, scsi_check_passthrough(&sc));
+}
+
+static struct kunit_case scsi_test_error_cases[] = {
+	KUNIT_CASE(scsi_test_error_check_passthough),
+	{}
+};
+
+static struct kunit_suite scsi_test_error_suite = {
+	.name = "scsi_error",
+	.test_cases = scsi_test_error_cases,
+};
+
+kunit_test_suite(scsi_test_error_suite);
-- 
2.34.1

Re: [PATCH v10 00/33] scsi: Allow scsi_execute users to control retries

[Bart Van Assche]

On 7/14/23 14:33, Mike Christie wrote:
> v2:
> - Rename scsi_prep_sense
> - Change scsi_check_passthrough's loop and added some fixes
> - Modified scsi_execute* so it uses a struct to pass in args

Hi Mike,

It seems like the diffstat is missing? For large patch series it is 
convenient if a diffstat is provided.

Thanks,

Bart.