[PATCH v2 00/18] Add Command Duration Limits support

[PATCH v2 00/18] Add Command Duration Limits support

[Niklas Cassel]

Hello,

This series adds support for Command Duration Limits.
The series is based on linux-next tag: next-20230112
The series can also be found in git:
https://github.com/floatious/linux/commits/cdl-v2


=================
CDL in ATA / SCSI
=================
Command Duration Limits is defined in:
T13 ATA Command Set - 5 (ACS-5) and
T10 SCSI Primary Commands - 6 (SPC-6) respectively
(a simpler version of CDL is defined in T10 SPC-5).

CDL defines Duration Limits Descriptors (DLD).
7 DLDs for read commands and 7 DLDs for write commands.
Simply put, a DLD contains a limit and a policy.

A command can specify that a certain limit should be applied by setting
the DLD index field (3 bits, so 0-7) in the command itself.

The DLD index points to one of the 7 DLDs.
DLD index 0 means no descriptor, so no limit.
DLD index 1-7 means DLD 1-7.

A DLD can have a few different policies, but the two major ones are:
-Policy 0xF (abort), command will be completed with command aborted error
(ATA) or status CHECK CONDITION (SCSI), with sense data indicating that
the command timed out.
-Policy 0xD (complete-unavailable), command will be completed without
error (ATA) or status GOOD (SCSI), with sense data indicating that the
command timed out. Note that the command will not have transferred any
data to/from the device when the command timed out, even though the
command returned success.

Regardless of the CDL policy, in case of a CDL timeout, the I/O will
result in a -ETIME error to user-space.

The DLDs are defined in the CDL log page(s) and are readable and writable.
For convenience, the kernel provides a sysfs interface for reading the
descriptors. If a user really wants to change the descriptors, they can do
so using a user-space application that sends passthrough commands,
one such application is cdl-tools:
https://github.com/westerndigitalcorporation/cdl-tools


==============================
How to use CDL from user-space
==============================
Since CDL is mutually exclusive with NCQ priority
(see ncq_prio_enable and sas_ncq_prio_enable in
Documentation/ABI/testing/sysfs-block-device),
CDL has to be enabled using:
echo 1 > /sys/block/$bdev/device/duration_limits/enable

In order for user-space to be able to select a specific DLD for an I/O,
we have decided to reuse the I/O priority API.

This means that we introduce a new priority class (IOPRIO_CLASS_DL).
When using this class, the existing I/O priority levels (0-7) directly
indicates the DLD index to use.

By reusing the I/O priority API, the user can both define DLD to use
per AIO (io_uring sqe->ioprio or libaio iocb->aio_reqprio) or per-thread
(ioprio_set()).


=======
Testing
=======
With the following fio patch that simply adds the new priority class:
https://github.com/westerndigitalcorporation/cdl-tools/blob/main/patches/fio-3.29-and-newer/0001-os-linux-Add-IORPIO_CLASS_DL-definition.patch

CDL can be tested using fio, e.g.:
fio --ioengine=io_uring --cmdprio_percentage=10 --cmdprio_class=4 --cmdprio=DLD_index

A simple way to test is to use a DLD with a very short duration limit,
and send large reads. Regardless of the CDL policy, in case of a CDL
timeout, the I/O will result in a -ETIME error to user-space.

We also provide a CDL test suite located in the cdl-tools repo, see:
https://github.com/westerndigitalcorporation/cdl-tools/blob/main/README.md#testing-a-system-command-duration-limits-support


We have tested this patch series using:
-real hardware
-the following QEMU implementation:
https://github.com/floatious/qemu/tree/cdl
(NOTE: the QEMU implementation requires you to define the CDL policy at compile
time, so you currently need to recompile QEMU when switching between policies.)


===================
Further information
===================
For further information about CDL, see Damien's slides:

Presented at SDC 2021:
https://www.snia.org/sites/default/files/SDC/2021/pdfs/SNIA-SDC21-LeMoal-Be-On-Time-command-duration-limits-Feature-Support-in%20Linux.pdf

Presented at Lund Linux Con 2022:
https://drive.google.com/file/d/1I6ChFc0h4JY9qZdO1bY5oCAdYCSZVqWw/view?usp=sharing


================
Changes since V1
================
-libata patches that were not strictly related to CDL have been dropped,
 as they have already been sent out and been accepted as a separate series:
 https://lore.kernel.org/linux-ide/20221229170005.49118-1-niklas.cassel@wdc.com/
-Sending all patches to all mailing lists (libata,scsi,block), instead of only
 sending the cover letter + relevant patches to each list (Chaitanya Kulkarni).
-Added my Signed-off-by on the patches developed solely by Damien (John Garry).
-Fixed comments on the Documentation (Bagas Sanjaya).
-Renamed SCSI ML helper while moving it (Mike Christie).
-Modified patch 17 ("ata: libata: handle completion of CDL commands using policy
 0xD") to not trigger the libata fast drain timer (which is 2 seconds) while
 scheduling SCSI EH for a CDL command (i.e. while waiting for other commands to
 finish normally). The regular 30 second SCSI timeout is still in place for the
 commands that we are waiting for to finish normally.
-Rebased and resolved merge conflicts in libata introduced by the now accepted
 libata FUA cleanup series.
-Rebased and resolved merge conflicts in bfq-iosched introduced by the now
 accepted BFQ multi actuator series.


Kind regards,
Niklas & Damien

Damien Le Moal (12):
  scsi: support retrieving sub-pages of mode pages
  scsi: support service action in scsi_report_opcode()
  block: introduce duration-limits priority class
  block: introduce BLK_STS_DURATION_LIMIT
  ata: libata: detect support for command duration limits
  ata: libata-scsi: handle CDL bits in ata_scsiop_maint_in()
  ata: libata-scsi: add support for CDL pages mode sense
  ata: libata: add ATA feature control sub-page translation
  ata: libata: set read/write commands CDL index
  scsi: sd: detect support for command duration limits
  scsi: sd: set read/write commands CDL index
  Documentation: sysfs-block-device: document command duration limits

Niklas Cassel (6):
  ata: libata: allow ata_scsi_set_sense() to not set CHECK_CONDITION
  ata: libata: allow ata_eh_request_sense() to not set CHECK_CONDITION
  scsi: core: allow libata to complete successful commands via EH
  scsi: rename and move get_scsi_ml_byte()
  scsi: sd: handle read/write CDL timeout failures
  ata: libata: handle completion of CDL commands using policy 0xD

 Documentation/ABI/testing/sysfs-block-device | 150 ++++
 block/bfq-iosched.c                          |  10 +
 block/blk-core.c                             |   3 +
 block/blk-ioprio.c                           |   3 +
 block/ioprio.c                               |   3 +-
 block/mq-deadline.c                          |   1 +
 drivers/ata/libata-core.c                    | 215 ++++-
 drivers/ata/libata-eh.c                      | 117 ++-
 drivers/ata/libata-sata.c                    | 104 ++-
 drivers/ata/libata-scsi.c                    | 403 +++++++--
 drivers/ata/libata.h                         |   6 +-
 drivers/scsi/Makefile                        |   2 +-
 drivers/scsi/scsi.c                          |  28 +-
 drivers/scsi/scsi_error.c                    |  49 +-
 drivers/scsi/scsi_lib.c                      |  15 +-
 drivers/scsi/scsi_priv.h                     |   6 +
 drivers/scsi/scsi_transport_sas.c            |   2 +-
 drivers/scsi/sd.c                            |  37 +-
 drivers/scsi/sd.h                            |  71 ++
 drivers/scsi/sd_cdl.c                        | 894 +++++++++++++++++++
 drivers/scsi/sr.c                            |   2 +-
 include/linux/ata.h                          |  11 +-
 include/linux/blk_types.h                    |   6 +
 include/linux/ioprio.h                       |   2 +-
 include/linux/libata.h                       |  42 +-
 include/scsi/scsi_cmnd.h                     |   5 +
 include/scsi/scsi_device.h                   |   8 +-
 include/uapi/linux/ioprio.h                  |   7 +
 28 files changed, 2051 insertions(+), 151 deletions(-)
 create mode 100644 drivers/scsi/sd_cdl.c

-- 
2.39.0

[PATCH v2 01/18] ata: libata: allow ata_scsi_set_sense() to not set CHECK_CONDITION

[Niklas Cassel]

Current ata_scsi_set_sense() calls scsi_build_sense(), which,
in addition to setting the sense data, unconditionally sets the
scsicmd->result to SAM_STAT_CHECK_CONDITION.

For Command Duration Limits policy 0xD:
The device shall complete the command without error (SAM_STAT_GOOD)
with the additional sense code set to DATA CURRENTLY UNAVAILABLE.

It is perfectly fine to have sense data for a command that returned
completion without error.

In order to support for CDL policy 0xD, we have to remove this
assumption that having sense data means that the command failed
(SAM_STAT_CHECK_CONDITION).

Add a new parameter to ata_scsi_set_sense() to allow us to set
sense data without unconditionally setting SAM_STAT_CHECK_CONDITION.
This new parameter will be used in a follow-up patch.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-eh.c   |  3 ++-
 drivers/ata/libata-sata.c |  4 ++--
 drivers/ata/libata-scsi.c | 38 ++++++++++++++++++++------------------
 drivers/ata/libata.h      |  4 ++--
 4 files changed, 26 insertions(+), 23 deletions(-)

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index a6c901811802..3521f3f67f5a 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1432,7 +1432,8 @@ static void ata_eh_request_sense(struct ata_queued_cmd *qc)
 	/* Ignore err_mask; ATA_ERR might be set */
 	if (tf.status & ATA_SENSE) {
 		if (ata_scsi_sense_is_valid(tf.lbah, tf.lbam, tf.lbal)) {
-			ata_scsi_set_sense(dev, cmd, tf.lbah, tf.lbam, tf.lbal);
+			ata_scsi_set_sense(dev, cmd, true, tf.lbah, tf.lbam,
+					   tf.lbal);
 			qc->flags |= ATA_QCFLAG_SENSE_VALID;
 		}
 	} else {
diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index f3e7396e3191..414d7f8a95bf 100644
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -1471,8 +1471,8 @@ void ata_eh_analyze_ncq_error(struct ata_link *link)
 		asc = (qc->result_tf.auxiliary >> 8) & 0xff;
 		ascq = qc->result_tf.auxiliary & 0xff;
 		if (ata_scsi_sense_is_valid(sense_key, asc, ascq)) {
-			ata_scsi_set_sense(dev, qc->scsicmd, sense_key, asc,
-					   ascq);
+			ata_scsi_set_sense(dev, qc->scsicmd, true, sense_key,
+					   asc, ascq);
 			ata_scsi_set_sense_information(dev, qc->scsicmd,
 						       &qc->result_tf);
 			qc->flags |= ATA_QCFLAG_SENSE_VALID;
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index aa338f10cef2..6d4ee296450e 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -205,14 +205,16 @@ bool ata_scsi_sense_is_valid(u8 sk, u8 asc, u8 ascq)
 }
 
 void ata_scsi_set_sense(struct ata_device *dev, struct scsi_cmnd *cmd,
-			u8 sk, u8 asc, u8 ascq)
+			bool check_condition, u8 sk, u8 asc, u8 ascq)
 {
 	bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
 
 	if (!cmd)
 		return;
 
-	scsi_build_sense(cmd, d_sense, sk, asc, ascq);
+	scsi_build_sense_buffer(d_sense, cmd->sense_buffer, sk, asc, ascq);
+	if (check_condition)
+		set_status_byte(cmd, SAM_STAT_CHECK_CONDITION);
 }
 
 void ata_scsi_set_sense_information(struct ata_device *dev,
@@ -235,7 +237,7 @@ void ata_scsi_set_sense_information(struct ata_device *dev,
 static void ata_scsi_set_invalid_field(struct ata_device *dev,
 				       struct scsi_cmnd *cmd, u16 field, u8 bit)
 {
-	ata_scsi_set_sense(dev, cmd, ILLEGAL_REQUEST, 0x24, 0x0);
+	ata_scsi_set_sense(dev, cmd, true, ILLEGAL_REQUEST, 0x24, 0x0);
 	/* "Invalid field in CDB" */
 	scsi_set_sense_field_pointer(cmd->sense_buffer, SCSI_SENSE_BUFFERSIZE,
 				     field, bit, 1);
@@ -245,7 +247,7 @@ static void ata_scsi_set_invalid_parameter(struct ata_device *dev,
 					   struct scsi_cmnd *cmd, u16 field)
 {
 	/* "Invalid field in parameter list" */
-	ata_scsi_set_sense(dev, cmd, ILLEGAL_REQUEST, 0x26, 0x0);
+	ata_scsi_set_sense(dev, cmd, true, ILLEGAL_REQUEST, 0x26, 0x0);
 	scsi_set_sense_field_pointer(cmd->sense_buffer, SCSI_SENSE_BUFFERSIZE,
 				     field, 0xff, 0);
 }
@@ -914,7 +916,7 @@ static void ata_gen_passthru_sense(struct ata_queued_cmd *qc)
 	    tf->status & (ATA_BUSY | ATA_DF | ATA_ERR | ATA_DRQ)) {
 		ata_to_sense_error(qc->ap->print_id, tf->status, tf->error,
 				   &sense_key, &asc, &ascq, verbose);
-		ata_scsi_set_sense(qc->dev, cmd, sense_key, asc, ascq);
+		ata_scsi_set_sense(qc->dev, cmd, true, sense_key, asc, ascq);
 	} else {
 		/*
 		 * ATA PASS-THROUGH INFORMATION AVAILABLE
@@ -1005,7 +1007,7 @@ static void ata_gen_ata_sense(struct ata_queued_cmd *qc)
 	if (ata_dev_disabled(dev)) {
 		/* Device disabled after error recovery */
 		/* LOGICAL UNIT NOT READY, HARD RESET REQUIRED */
-		ata_scsi_set_sense(dev, cmd, NOT_READY, 0x04, 0x21);
+		ata_scsi_set_sense(dev, cmd, true, NOT_READY, 0x04, 0x21);
 		return;
 	}
 	/* Use ata_to_sense_error() to map status register bits
@@ -1015,12 +1017,12 @@ static void ata_gen_ata_sense(struct ata_queued_cmd *qc)
 	    tf->status & (ATA_BUSY | ATA_DF | ATA_ERR | ATA_DRQ)) {
 		ata_to_sense_error(qc->ap->print_id, tf->status, tf->error,
 				   &sense_key, &asc, &ascq, verbose);
-		ata_scsi_set_sense(dev, cmd, sense_key, asc, ascq);
+		ata_scsi_set_sense(dev, cmd, true, sense_key, asc, ascq);
 	} else {
 		/* Could not decode error */
 		ata_dev_warn(dev, "could not decode error status 0x%x err_mask 0x%x\n",
 			     tf->status, qc->err_mask);
-		ata_scsi_set_sense(dev, cmd, ABORTED_COMMAND, 0, 0);
+		ata_scsi_set_sense(dev, cmd, true, ABORTED_COMMAND, 0, 0);
 		return;
 	}
 
@@ -1496,7 +1498,7 @@ static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc)
 	return 1;
 
 out_of_range:
-	ata_scsi_set_sense(qc->dev, scmd, ILLEGAL_REQUEST, 0x21, 0x0);
+	ata_scsi_set_sense(qc->dev, scmd, true, ILLEGAL_REQUEST, 0x21, 0x0);
 	/* "Logical Block Address out of range" */
 	return 1;
 
@@ -1631,7 +1633,7 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
 	return 1;
 
 out_of_range:
-	ata_scsi_set_sense(qc->dev, scmd, ILLEGAL_REQUEST, 0x21, 0x0);
+	ata_scsi_set_sense(qc->dev, scmd, true, ILLEGAL_REQUEST, 0x21, 0x0);
 	/* "Logical Block Address out of range" */
 	return 1;
 
@@ -2354,7 +2356,7 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
 	return 1;
 
 saving_not_supp:
-	ata_scsi_set_sense(dev, args->cmd, ILLEGAL_REQUEST, 0x39, 0x0);
+	ata_scsi_set_sense(dev, args->cmd, true, ILLEGAL_REQUEST, 0x39, 0x0);
 	 /* "Saving parameters not supported" */
 	return 1;
 }
@@ -3215,11 +3217,11 @@ static unsigned int ata_scsi_write_same_xlat(struct ata_queued_cmd *qc)
 	return 1;
 invalid_param_len:
 	/* "Parameter list length error" */
-	ata_scsi_set_sense(dev, scmd, ILLEGAL_REQUEST, 0x1a, 0x0);
+	ata_scsi_set_sense(dev, scmd, true, ILLEGAL_REQUEST, 0x1a, 0x0);
 	return 1;
 invalid_opcode:
 	/* "Invalid command operation code" */
-	ata_scsi_set_sense(dev, scmd, ILLEGAL_REQUEST, 0x20, 0x0);
+	ata_scsi_set_sense(dev, scmd, true, ILLEGAL_REQUEST, 0x20, 0x0);
 	return 1;
 }
 
@@ -3446,7 +3448,7 @@ static unsigned int ata_scsi_zbc_in_xlat(struct ata_queued_cmd *qc)
 
 invalid_param_len:
 	/* "Parameter list length error" */
-	ata_scsi_set_sense(qc->dev, scmd, ILLEGAL_REQUEST, 0x1a, 0x0);
+	ata_scsi_set_sense(qc->dev, scmd, true, ILLEGAL_REQUEST, 0x1a, 0x0);
 	return 1;
 }
 
@@ -3524,7 +3526,7 @@ static unsigned int ata_scsi_zbc_out_xlat(struct ata_queued_cmd *qc)
 	return 1;
 invalid_param_len:
 	/* "Parameter list length error" */
-	ata_scsi_set_sense(qc->dev, scmd, ILLEGAL_REQUEST, 0x1a, 0x0);
+	ata_scsi_set_sense(qc->dev, scmd, true, ILLEGAL_REQUEST, 0x1a, 0x0);
 	return 1;
 }
 
@@ -3785,7 +3787,7 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
 
  invalid_param_len:
 	/* "Parameter list length error" */
-	ata_scsi_set_sense(qc->dev, scmd, ILLEGAL_REQUEST, 0x1a, 0x0);
+	ata_scsi_set_sense(qc->dev, scmd, true, ILLEGAL_REQUEST, 0x1a, 0x0);
 	return 1;
 
  skip:
@@ -4141,7 +4143,7 @@ void ata_scsi_simulate(struct ata_device *dev, struct scsi_cmnd *cmd)
 		break;
 
 	case REQUEST_SENSE:
-		ata_scsi_set_sense(dev, cmd, 0, 0, 0);
+		ata_scsi_set_sense(dev, cmd, true, 0, 0, 0);
 		break;
 
 	/* if we reach this, then writeback caching is disabled,
@@ -4173,7 +4175,7 @@ void ata_scsi_simulate(struct ata_device *dev, struct scsi_cmnd *cmd)
 
 	/* all other commands */
 	default:
-		ata_scsi_set_sense(dev, cmd, ILLEGAL_REQUEST, 0x20, 0x0);
+		ata_scsi_set_sense(dev, cmd, true, ILLEGAL_REQUEST, 0x20, 0x0);
 		/* "Invalid command operation code" */
 		break;
 	}
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 2cd6124a01e8..5481d29bb273 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -115,8 +115,8 @@ extern int ata_scsi_add_hosts(struct ata_host *host,
 extern void ata_scsi_scan_host(struct ata_port *ap, int sync);
 extern int ata_scsi_offline_dev(struct ata_device *dev);
 extern bool ata_scsi_sense_is_valid(u8 sk, u8 asc, u8 ascq);
-extern void ata_scsi_set_sense(struct ata_device *dev,
-			       struct scsi_cmnd *cmd, u8 sk, u8 asc, u8 ascq);
+extern void ata_scsi_set_sense(struct ata_device *dev, struct scsi_cmnd *cmd,
+			       bool check_condition, u8 sk, u8 asc, u8 ascq);
 extern void ata_scsi_set_sense_information(struct ata_device *dev,
 					   struct scsi_cmnd *cmd,
 					   const struct ata_taskfile *tf);
-- 
2.39.0

[PATCH v2 02/18] ata: libata: allow ata_eh_request_sense() to not set CHECK_CONDITION

[Niklas Cassel]

Current ata_eh_request_sense() calls ata_scsi_set_sense() with
check_condition always set to true, which, in addition to setting the
sense data, unconditionally sets the scsicmd->result to
SAM_STAT_CHECK_CONDITION.

For Command Duration Limits policy 0xD:
The device shall complete the command without error (SAM_STAT_GOOD)
with the additional sense code set to DATA CURRENTLY UNAVAILABLE.

It is perfectly fine to have sense data for a command that returned
completion without error.

In order to support for CDL policy 0xD, we have to remove this
assumption that having sense data means that the command failed
(SAM_STAT_CHECK_CONDITION).

Add a new parameter to ata_eh_request_sense() to allow us to request
sense data without unconditionally setting SAM_STAT_CHECK_CONDITION.
This new parameter will be used in a follow-up patch.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-eh.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 3521f3f67f5a..1c3d55fc1cae 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1395,6 +1395,7 @@ unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
 /**
  *	ata_eh_request_sense - perform REQUEST_SENSE_DATA_EXT
  *	@qc: qc to perform REQUEST_SENSE_SENSE_DATA_EXT to
+ *	@check_condition: if SAM_STAT_CHECK_CONDITION should get set
  *
  *	Perform REQUEST_SENSE_DATA_EXT after the device reported CHECK
  *	SENSE.  This function is an EH helper.
@@ -1402,7 +1403,8 @@ unsigned int atapi_eh_tur(struct ata_device *dev, u8 *r_sense_key)
  *	LOCKING:
  *	Kernel thread context (may sleep).
  */
-static void ata_eh_request_sense(struct ata_queued_cmd *qc)
+static void ata_eh_request_sense(struct ata_queued_cmd *qc,
+				 bool check_condition)
 {
 	struct scsi_cmnd *cmd = qc->scsicmd;
 	struct ata_device *dev = qc->dev;
@@ -1432,8 +1434,8 @@ static void ata_eh_request_sense(struct ata_queued_cmd *qc)
 	/* Ignore err_mask; ATA_ERR might be set */
 	if (tf.status & ATA_SENSE) {
 		if (ata_scsi_sense_is_valid(tf.lbah, tf.lbam, tf.lbal)) {
-			ata_scsi_set_sense(dev, cmd, true, tf.lbah, tf.lbam,
-					   tf.lbal);
+			ata_scsi_set_sense(dev, cmd, check_condition, tf.lbah,
+					   tf.lbam, tf.lbal);
 			qc->flags |= ATA_QCFLAG_SENSE_VALID;
 		}
 	} else {
@@ -1590,7 +1592,7 @@ static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc)
 		 *  (i.e. NCQ autosense is not supported by the device).
 		 */
 		if (!(qc->flags & ATA_QCFLAG_SENSE_VALID) && (stat & ATA_SENSE))
-			ata_eh_request_sense(qc);
+			ata_eh_request_sense(qc, true);
 		if (err & ATA_ICRC)
 			qc->err_mask |= AC_ERR_ATA_BUS;
 		if (err & (ATA_UNC | ATA_AMNF))
-- 
2.39.0

[PATCH v2 03/18] scsi: core: allow libata to complete successful commands via EH

[Niklas Cassel]

In SCSI, we get the sense data as part of the completion, for ATA
however, we need to fetch the sense data as an extra step. For an
aborted ATA command the sense data is fetched via libata's
->eh_strategy_handler().

For Command Duration Limits policy 0xD:
The device shall complete the command without error with the additional
sense code set to DATA CURRENTLY UNAVAILABLE.

In order to handle this policy in libata, we intend to send a successful
command via SCSI EH, and let libata's ->eh_strategy_handler() fetch the
sense data for the good command. This is similar to how we handle an
aborted ATA command, just that we need to read the Successful NCQ
Commands log instead of the NCQ Command Error log.

When we get a SATA completion with successful commands, ATA_SENSE will
be set, indicating that some commands in the completion have sense data.

The sense_valid bitmask in the Sense Data for Successful NCQ Commands
log will inform exactly which commands that had sense data, which might
be a subset of all the commands that was completed in the same
completion. (Yet all will have ATA_SENSE set, since the status is per
completion.)

The successful commands that have e.g. a "DATA CURRENTLY UNAVAILABLE"
sense data will have a SCSI ML byte set, so scsi_eh_flush_done_q() will
not set the scmd->result to DID_TIME_OUT for these commands. However,
the successful commands that did not have sense data, must not get their
result marked as DID_TIME_OUT by SCSI EH.

Add a new flag SCMD_EH_SUCCESS_CMD, which tells SCSI EH to not mark a
command as DID_TIME_OUT, even if it has scmd->result == SAM_STAT_GOOD.

This will be used by libata in a follow-up patch.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/scsi/scsi_error.c | 3 ++-
 include/scsi/scsi_cmnd.h  | 5 +++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 2aa2c2aee6e7..51aa5c1e31b5 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -2165,7 +2165,8 @@ void scsi_eh_flush_done_q(struct list_head *done_q)
 			 * scsi_eh_get_sense), scmd->result is already
 			 * set, do not set DID_TIME_OUT.
 			 */
-			if (!scmd->result)
+			if (!scmd->result &&
+			    !(scmd->flags & SCMD_EH_SUCCESS_CMD))
 				scmd->result |= (DID_TIME_OUT << 16);
 			SCSI_LOG_ERROR_RECOVERY(3,
 				scmd_printk(KERN_INFO, scmd,
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index c2cb5f69635c..c027648dba04 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -52,6 +52,11 @@ struct scsi_pointer {
 #define SCMD_TAGGED		(1 << 0)
 #define SCMD_INITIALIZED	(1 << 1)
 #define SCMD_LAST		(1 << 2)
+/*
+ * libata uses SCSI EH to fetch sense data for successful commands.
+ * SCSI EH should not overwrite scmd->result when SCMD_EH_SUCCESS_CMD is set.
+ */
+#define SCMD_EH_SUCCESS_CMD	(1 << 3)
 #define SCMD_FAIL_IF_RECOVERING	(1 << 4)
 /* flags preserved across unprep / reprep */
 #define SCMD_PRESERVED_FLAGS	(SCMD_INITIALIZED | SCMD_FAIL_IF_RECOVERING)
-- 
2.39.0

[PATCH v2 04/18] scsi: rename and move get_scsi_ml_byte()

[Niklas Cassel]

SCSI has two different getters:
- get_XXX_byte() (in scsi_cmnd.h) which takes a struct scsi_cmnd *, and
- XXX_byte() (in scsi.h) which takes a scmd->result.
The proper name for get_scsi_ml_byte() should thus be without the get_
prefix, as it takes a scmd->result. Rename the function to rectify this.

Additionally, move get_scsi_ml_byte() to scsi_priv.h since both scsi_lib.c
and scsi_error.c will need to use this helper in a follow-up patch.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/scsi/scsi_lib.c  | 7 +------
 drivers/scsi/scsi_priv.h | 5 +++++
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9ed1ebcb7443..6630a36b873e 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -579,11 +579,6 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
 	return false;
 }
 
-static inline u8 get_scsi_ml_byte(int result)
-{
-	return (result >> 8) & 0xff;
-}
-
 /**
  * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
  * @result:	scsi error code
@@ -596,7 +591,7 @@ static blk_status_t scsi_result_to_blk_status(int result)
 	 * Check the scsi-ml byte first in case we converted a host or status
 	 * byte.
 	 */
-	switch (get_scsi_ml_byte(result)) {
+	switch (scsi_ml_byte(result)) {
 	case SCSIML_STAT_OK:
 		break;
 	case SCSIML_STAT_RESV_CONFLICT:
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index 96284a0e13fe..74324fba4281 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -29,6 +29,11 @@ enum scsi_ml_status {
 	SCSIML_STAT_TGT_FAILURE		= 0x04,	/* Permanent target failure */
 };
 
+static inline u8 scsi_ml_byte(int result)
+{
+	return (result >> 8) & 0xff;
+}
+
 /*
  * Scsi Error Handler Flags
  */
-- 
2.39.0

[PATCH v2 05/18] scsi: support retrieving sub-pages of mode pages

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Allow scsi_mode_sense() to retrieve sub-pages of mode pages by adding
the subpage argument. Change all the current caller sites to specify
the subpage 0.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/scsi/scsi_lib.c           | 4 +++-
 drivers/scsi/scsi_transport_sas.c | 2 +-
 drivers/scsi/sd.c                 | 9 ++++-----
 drivers/scsi/sr.c                 | 2 +-
 include/scsi/scsi_device.h        | 5 +++--
 5 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 6630a36b873e..79cece5eff5d 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2142,6 +2142,7 @@ EXPORT_SYMBOL_GPL(scsi_mode_select);
  *	@sdev:	SCSI device to be queried
  *	@dbd:	set to prevent mode sense from returning block descriptors
  *	@modepage: mode page being requested
+ *	@subpage: sub-page of the mode page being requested
  *	@buffer: request buffer (may not be smaller than eight bytes)
  *	@len:	length of request buffer.
  *	@timeout: command timeout
@@ -2153,7 +2154,7 @@ EXPORT_SYMBOL_GPL(scsi_mode_select);
  *	Returns zero if successful, or a negative error number on failure
  */
 int
-scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
+scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage,
 		  unsigned char *buffer, int len, int timeout, int retries,
 		  struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
 {
@@ -2169,6 +2170,7 @@ scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
 	dbd = sdev->set_dbd_for_ms ? 8 : dbd;
 	cmd[1] = dbd & 0x18;	/* allows DBD and LLBA bits */
 	cmd[2] = modepage;
+	cmd[3] = subpage;
 
 	/* caller might not be interested in sense, but we need it */
 	if (!sshdr)
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index 74b99f2b0b74..d704c484a251 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -1245,7 +1245,7 @@ int sas_read_port_mode_page(struct scsi_device *sdev)
 	if (!buffer)
 		return -ENOMEM;
 
-	error = scsi_mode_sense(sdev, 1, 0x19, buffer, BUF_SIZE, 30*HZ, 3,
+	error = scsi_mode_sense(sdev, 1, 0x19, 0, buffer, BUF_SIZE, 30*HZ, 3,
 				&mode_data, NULL);
 
 	if (error)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 47dafe6b8a66..77259716ca75 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -184,7 +184,7 @@ cache_type_store(struct device *dev, struct device_attribute *attr,
 		return count;
 	}
 
-	if (scsi_mode_sense(sdp, 0x08, 8, buffer, sizeof(buffer), SD_TIMEOUT,
+	if (scsi_mode_sense(sdp, 0x08, 8, 0, buffer, sizeof(buffer), SD_TIMEOUT,
 			    sdkp->max_retries, &data, NULL))
 		return -EINVAL;
 	len = min_t(size_t, sizeof(buffer), data.length - data.header_length -
@@ -2596,9 +2596,8 @@ sd_do_mode_sense(struct scsi_disk *sdkp, int dbd, int modepage,
 	if (sdkp->device->use_10_for_ms && len < 8)
 		len = 8;
 
-	return scsi_mode_sense(sdkp->device, dbd, modepage, buffer, len,
-			       SD_TIMEOUT, sdkp->max_retries, data,
-			       sshdr);
+	return scsi_mode_sense(sdkp->device, dbd, modepage, 0, buffer, len,
+			       SD_TIMEOUT, sdkp->max_retries, data, sshdr);
 }
 
 /*
@@ -2855,7 +2854,7 @@ static void sd_read_app_tag_own(struct scsi_disk *sdkp, unsigned char *buffer)
 	if (sdkp->protection_type == 0)
 		return;
 
-	res = scsi_mode_sense(sdp, 1, 0x0a, buffer, 36, SD_TIMEOUT,
+	res = scsi_mode_sense(sdp, 1, 0x0a, 0, buffer, 36, SD_TIMEOUT,
 			      sdkp->max_retries, &data, &sshdr);
 
 	if (res < 0 || !data.header_length ||
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index a278b739d0c5..d2bbde7172ac 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -827,7 +827,7 @@ static int get_capabilities(struct scsi_cd *cd)
 	scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr);
 
 	/* ask for mode page 0x2a */
-	rc = scsi_mode_sense(cd->device, 0, 0x2a, buffer, ms_len,
+	rc = scsi_mode_sense(cd->device, 0, 0x2a, 0, buffer, ms_len,
 			     SR_TIMEOUT, 3, &data, NULL);
 
 	if (rc < 0 || data.length > ms_len ||
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 3642b8e3928b..a499cdac2ce8 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -420,8 +420,9 @@ extern int scsi_track_queue_full(struct scsi_device *, int);
 extern int scsi_set_medium_removal(struct scsi_device *, char);
 
 extern int scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
-			   unsigned char *buffer, int len, int timeout,
-			   int retries, struct scsi_mode_data *data,
+			   int subpage, unsigned char *buffer, int len,
+			   int timeout, int retries,
+			   struct scsi_mode_data *data,
 			   struct scsi_sense_hdr *);
 extern int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
 			    unsigned char *buffer, int len, int timeout,
-- 
2.39.0

[PATCH v2 06/18] scsi: support service action in scsi_report_opcode()

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

The REPORT_SUPPORTED_OPERATION_CODES command allows checking for support
of commands that have the same opcode but different service actions,
such as READ 32 and WRITE 32. However, the current implementation of
scsi_report_opcode() only allows checking an operation code without a
service action differentiation.

Add the "sa" argument to scsi_report_opcode() to allow passing a service
action. If a non-zero service action is specified, the reporting
options field value is set to 3 to have the service action field taken
into account by the device. If no service action field is specified
(zero), the reporting options field is set to 1 as before.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/scsi/scsi.c        | 28 +++++++++++++++++++---------
 drivers/scsi/sd.c          | 10 +++++-----
 include/scsi/scsi_device.h |  3 ++-
 3 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 1426b9b03612..e69a5dd5abd2 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -494,18 +494,22 @@ void scsi_attach_vpd(struct scsi_device *sdev)
 }
 
 /**
- * scsi_report_opcode - Find out if a given command opcode is supported
+ * scsi_report_opcode - Find out if a given command is supported
  * @sdev:	scsi device to query
  * @buffer:	scratch buffer (must be at least 20 bytes long)
  * @len:	length of buffer
- * @opcode:	opcode for command to look up
- *
- * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
- * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
- * unsupported and 1 if the device claims to support the command.
+ * @opcode:	opcode for the command to look up
+ * @sa:		service action for the command to look up
+ *
+ * Uses the REPORT SUPPORTED OPERATION CODES to check support for the
+ * command identified with @opcode and @sa. If the command does not
+ * have a service action, @sa must be 0. Returns -EINVAL if RSOC fails,
+ * 0 if the command is not supported and 1 if the device claims to
+ * support the command.
  */
 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
-		       unsigned int len, unsigned char opcode)
+		       unsigned int len, unsigned char opcode,
+		       unsigned short sa)
 {
 	unsigned char cmd[16];
 	struct scsi_sense_hdr sshdr;
@@ -526,8 +530,14 @@ int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
 	memset(cmd, 0, 16);
 	cmd[0] = MAINTENANCE_IN;
 	cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
-	cmd[2] = 1;		/* One command format */
-	cmd[3] = opcode;
+	if (!sa) {
+		cmd[2] = 1;	/* One command format */
+		cmd[3] = opcode;
+	} else {
+		cmd[2] = 3;	/* One command format with service action */
+		cmd[3] = opcode;
+		put_unaligned_be16(sa, &cmd[4]);
+	}
 	put_unaligned_be32(request_len, &cmd[6]);
 	memset(buffer, 0, len);
 
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 77259716ca75..2b56ff4fcf8a 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3038,7 +3038,7 @@ static void sd_read_write_same(struct scsi_disk *sdkp, unsigned char *buffer)
 		return;
 	}
 
-	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, INQUIRY) < 0) {
+	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, INQUIRY, 0) < 0) {
 		struct scsi_vpd *vpd;
 
 		sdev->no_report_opcodes = 1;
@@ -3054,10 +3054,10 @@ static void sd_read_write_same(struct scsi_disk *sdkp, unsigned char *buffer)
 		rcu_read_unlock();
 	}
 
-	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, WRITE_SAME_16) == 1)
+	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, WRITE_SAME_16, 0) == 1)
 		sdkp->ws16 = 1;
 
-	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, WRITE_SAME) == 1)
+	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE, WRITE_SAME, 0) == 1)
 		sdkp->ws10 = 1;
 }
 
@@ -3069,9 +3069,9 @@ static void sd_read_security(struct scsi_disk *sdkp, unsigned char *buffer)
 		return;
 
 	if (scsi_report_opcode(sdev, buffer, SD_BUF_SIZE,
-			SECURITY_PROTOCOL_IN) == 1 &&
+			SECURITY_PROTOCOL_IN, 0) == 1 &&
 	    scsi_report_opcode(sdev, buffer, SD_BUF_SIZE,
-			SECURITY_PROTOCOL_OUT) == 1)
+			SECURITY_PROTOCOL_OUT, 0) == 1)
 		sdkp->security = 1;
 }
 
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index a499cdac2ce8..f6d1d9890839 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -433,7 +433,8 @@ extern int scsi_test_unit_ready(struct scsi_device *sdev, int timeout,
 extern int scsi_get_vpd_page(struct scsi_device *, u8 page, unsigned char *buf,
 			     int buf_len);
 extern int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
-			      unsigned int len, unsigned char opcode);
+			      unsigned int len, unsigned char opcode,
+			      unsigned short sa);
 extern int scsi_device_set_state(struct scsi_device *sdev,
 				 enum scsi_device_state state);
 extern struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
-- 
2.39.0

[PATCH v2 07/18] block: introduce duration-limits priority class

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Introduce the IOPRIO_CLASS_DL priority class to indicate that IOs should
be executed using duration-limits targets. The duration target to apply
to a command is indicated using the priority level. Up to 8 levels are
supported, with level 0 indiating "no limit".

This priority class has effect only if the target device supports the
command duration limits feature and this feature is enabled by the user.
In BFQ and mq-deadline, all requests with this new priority class are
handled using the highest priority class RT and priority level 0.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 block/bfq-iosched.c         | 10 ++++++++++
 block/blk-ioprio.c          |  3 +++
 block/ioprio.c              |  3 ++-
 block/mq-deadline.c         |  1 +
 include/linux/ioprio.h      |  2 +-
 include/uapi/linux/ioprio.h |  7 +++++++
 6 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 815b884d6c5a..7add9346c585 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5545,6 +5545,14 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic)
 		bfqq->new_ioprio_class = IOPRIO_CLASS_IDLE;
 		bfqq->new_ioprio = 7;
 		break;
+	case IOPRIO_CLASS_DL:
+		/*
+		 * For the duration-limits class, we want the disk to do the
+		 * scheduling. So map all levels to the highest RT level.
+		 */
+		bfqq->new_ioprio = 0;
+		bfqq->new_ioprio_class = IOPRIO_CLASS_RT;
+		break;
 	}
 
 	if (bfqq->new_ioprio >= IOPRIO_NR_LEVELS) {
@@ -5673,6 +5681,8 @@ static struct bfq_queue **bfq_async_queue_prio(struct bfq_data *bfqd,
 		return &bfqg->async_bfqq[1][ioprio][act_idx];
 	case IOPRIO_CLASS_IDLE:
 		return &bfqg->async_idle_bfqq[act_idx];
+	case IOPRIO_CLASS_DL:
+		return &bfqg->async_bfqq[0][0][act_idx];
 	default:
 		return NULL;
 	}
diff --git a/block/blk-ioprio.c b/block/blk-ioprio.c
index 8bb6b8eba4ce..dfb5c3f447f4 100644
--- a/block/blk-ioprio.c
+++ b/block/blk-ioprio.c
@@ -27,6 +27,7 @@
  * @POLICY_RESTRICT_TO_BE: modify IOPRIO_CLASS_NONE and IOPRIO_CLASS_RT into
  *		IOPRIO_CLASS_BE.
  * @POLICY_ALL_TO_IDLE: change the I/O priority class into IOPRIO_CLASS_IDLE.
+ * @POLICY_ALL_TO_DL: change the I/O priority class into IOPRIO_CLASS_DL.
  *
  * See also <linux/ioprio.h>.
  */
@@ -35,6 +36,7 @@ enum prio_policy {
 	POLICY_NONE_TO_RT	= 1,
 	POLICY_RESTRICT_TO_BE	= 2,
 	POLICY_ALL_TO_IDLE	= 3,
+	POLICY_ALL_TO_DL	= 4,
 };
 
 static const char *policy_name[] = {
@@ -42,6 +44,7 @@ static const char *policy_name[] = {
 	[POLICY_NONE_TO_RT]	= "none-to-rt",
 	[POLICY_RESTRICT_TO_BE]	= "restrict-to-be",
 	[POLICY_ALL_TO_IDLE]	= "idle",
+	[POLICY_ALL_TO_DL]	= "duration-limits",
 };
 
 static struct blkcg_policy ioprio_policy;
diff --git a/block/ioprio.c b/block/ioprio.c
index 32a456b45804..1b3a9da82597 100644
--- a/block/ioprio.c
+++ b/block/ioprio.c
@@ -37,6 +37,7 @@ int ioprio_check_cap(int ioprio)
 
 	switch (class) {
 		case IOPRIO_CLASS_RT:
+		case IOPRIO_CLASS_DL:
 			/*
 			 * Originally this only checked for CAP_SYS_ADMIN,
 			 * which was implicitly allowed for pid 0 by security
@@ -47,7 +48,7 @@ int ioprio_check_cap(int ioprio)
 			if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_NICE))
 				return -EPERM;
 			fallthrough;
-			/* rt has prio field too */
+			/* RT and DL have prio field too */
 		case IOPRIO_CLASS_BE:
 			if (data >= IOPRIO_NR_LEVELS || data < 0)
 				return -EINVAL;
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index f10c2a0d18d4..526d0ea4dbf9 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -113,6 +113,7 @@ static const enum dd_prio ioprio_class_to_prio[] = {
 	[IOPRIO_CLASS_RT]	= DD_RT_PRIO,
 	[IOPRIO_CLASS_BE]	= DD_BE_PRIO,
 	[IOPRIO_CLASS_IDLE]	= DD_IDLE_PRIO,
+	[IOPRIO_CLASS_DL]	= DD_RT_PRIO,
 };
 
 static inline struct rb_root *
diff --git a/include/linux/ioprio.h b/include/linux/ioprio.h
index 7578d4f6a969..2f3fc2fbd668 100644
--- a/include/linux/ioprio.h
+++ b/include/linux/ioprio.h
@@ -20,7 +20,7 @@ static inline bool ioprio_valid(unsigned short ioprio)
 {
 	unsigned short class = IOPRIO_PRIO_CLASS(ioprio);
 
-	return class > IOPRIO_CLASS_NONE && class <= IOPRIO_CLASS_IDLE;
+	return class > IOPRIO_CLASS_NONE && class <= IOPRIO_CLASS_DL;
 }
 
 /*
diff --git a/include/uapi/linux/ioprio.h b/include/uapi/linux/ioprio.h
index f70f2596a6bf..15908b9e9d8c 100644
--- a/include/uapi/linux/ioprio.h
+++ b/include/uapi/linux/ioprio.h
@@ -29,6 +29,7 @@ enum {
 	IOPRIO_CLASS_RT,
 	IOPRIO_CLASS_BE,
 	IOPRIO_CLASS_IDLE,
+	IOPRIO_CLASS_DL,
 };
 
 /*
@@ -37,6 +38,12 @@ enum {
 #define IOPRIO_NR_LEVELS	8
 #define IOPRIO_BE_NR		IOPRIO_NR_LEVELS
 
+/*
+ * The Duration limits class allows 8 levels: level 0 for "no limit" and levels
+ * 1 to 7, each corresponding to a read or write limit descriptor.
+ */
+#define IOPRIO_DL_NR_LEVELS	8
+
 enum {
 	IOPRIO_WHO_PROCESS = 1,
 	IOPRIO_WHO_PGRP,
-- 
2.39.0

[PATCH v2 08/18] block: introduce BLK_STS_DURATION_LIMIT

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Introduce the new block IO status BLK_STS_DURATION_LIMIT for LLDDs to
report command that failed due to a command duration limit being
exceeded. This new status is mapped to the ETIME error code to allow
users to differentiate "soft" duration limit failures from other more
serious hardware related errors.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 block/blk-core.c          | 3 +++
 include/linux/blk_types.h | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index b5098355d8b2..67b0b24aa171 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -170,6 +170,9 @@ static const struct {
 	[BLK_STS_ZONE_OPEN_RESOURCE]	= { -ETOOMANYREFS, "open zones exceeded" },
 	[BLK_STS_ZONE_ACTIVE_RESOURCE]	= { -EOVERFLOW, "active zones exceeded" },
 
+	/* Command duration limit device-side timeout */
+	[BLK_STS_DURATION_LIMIT]	= { -ETIME, "duration limit exceeded" },
+
 	/* everything else not covered above: */
 	[BLK_STS_IOERR]		= { -EIO,	"I/O" },
 };
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 99be590f952f..cde997590765 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -166,6 +166,12 @@ typedef u16 blk_short_t;
  */
 #define BLK_STS_OFFLINE		((__force blk_status_t)17)
 
+/*
+ * BLK_STS_DURATION_LIMIT is returned from the driver when the target device
+ * aborted the command because it exceeded one of its Command Duration Limits.
+ */
+#define BLK_STS_DURATION_LIMIT	((__force blk_status_t)18)
+
 /**
  * blk_path_error - returns true if error may be path related
  * @error: status the request was completed with
-- 
2.39.0

[PATCH v2 09/18] ata: libata: detect support for command duration limits

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Use the supported capabilities identify device data log page to detect
if a device supports the command duration limits feature. For devices
supporting this feature, set the device flag ATA_DFLAG_CDL. To support
scsi-ata translation, retrieve the command duration limits log page 18h
and cache this page content using the cdl array added to the ata_device
data structure.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-core.c | 52 ++++++++++++++++++++++++++++++++++++++-
 drivers/ata/libata-scsi.c | 17 ++++++-------
 include/linux/ata.h       |  5 +++-
 include/linux/libata.h    | 29 +++++++++++++---------
 4 files changed, 80 insertions(+), 23 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 36c1aca310e9..17e32b0a6364 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2367,6 +2367,54 @@ static void ata_dev_config_trusted(struct ata_device *dev)
 		dev->flags |= ATA_DFLAG_TRUSTED;
 }
 
+static void ata_dev_config_cdl(struct ata_device *dev)
+{
+	struct ata_port *ap = dev->link->ap;
+	unsigned int err_mask;
+	u64 val;
+
+	if (ata_id_major_version(dev->id) < 12)
+		goto not_supported;
+
+	if (!ata_log_supported(dev, ATA_LOG_IDENTIFY_DEVICE) ||
+	    !ata_identify_page_supported(dev, ATA_LOG_SUPPORTED_CAPABILITIES))
+		goto not_supported;
+
+	err_mask = ata_read_log_page(dev, ATA_LOG_IDENTIFY_DEVICE,
+				     ATA_LOG_SUPPORTED_CAPABILITIES,
+				     ap->sector_buf, 1);
+	if (err_mask)
+		goto not_supported;
+
+	/* Check Command Duration Limit Supported bits */
+	val = get_unaligned_le64(&ap->sector_buf[168]);
+	if (!(val & BIT_ULL(63)) || !(val & BIT_ULL(0)))
+		goto not_supported;
+
+	/* Warn the user if command duration guideline is not supported */
+	if (!(val & BIT_ULL(1)))
+		ata_dev_warn(dev,
+			"Command duration guideline is not supported\n");
+
+	/*
+	 * Command duration limits is supported: cache the CDL log page 18h
+	 * (command duration descriptors).
+	 */
+	err_mask = ata_read_log_page(dev, ATA_LOG_CDL, 0, ap->sector_buf, 1);
+	if (err_mask) {
+		ata_dev_warn(dev, "Read Command Duration Limits log failed\n");
+		goto not_supported;
+	}
+
+	memcpy(dev->cdl, ap->sector_buf, ATA_LOG_CDL_SIZE);
+	dev->flags |= ATA_DFLAG_CDL;
+
+	return;
+
+not_supported:
+	dev->flags &= ~ATA_DFLAG_CDL;
+}
+
 static int ata_dev_config_lba(struct ata_device *dev)
 {
 	const u16 *id = dev->id;
@@ -2534,13 +2582,14 @@ static void ata_dev_print_features(struct ata_device *dev)
 		return;
 
 	ata_dev_info(dev,
-		     "Features:%s%s%s%s%s%s%s\n",
+		     "Features:%s%s%s%s%s%s%s%s\n",
 		     dev->flags & ATA_DFLAG_FUA ? " FUA" : "",
 		     dev->flags & ATA_DFLAG_TRUSTED ? " Trust" : "",
 		     dev->flags & ATA_DFLAG_DA ? " Dev-Attention" : "",
 		     dev->flags & ATA_DFLAG_DEVSLP ? " Dev-Sleep" : "",
 		     dev->flags & ATA_DFLAG_NCQ_SEND_RECV ? " NCQ-sndrcv" : "",
 		     dev->flags & ATA_DFLAG_NCQ_PRIO ? " NCQ-prio" : "",
+		     dev->flags & ATA_DFLAG_CDL ? " CDL" : "",
 		     dev->cpr_log ? " CPR" : "");
 }
 
@@ -2702,6 +2751,7 @@ int ata_dev_configure(struct ata_device *dev)
 		ata_dev_config_zac(dev);
 		ata_dev_config_trusted(dev);
 		ata_dev_config_cpr(dev);
+		ata_dev_config_cdl(dev);
 		dev->cdb_len = 32;
 
 		if (print_info)
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 6d4ee296450e..c64bd3095ea6 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -47,15 +47,14 @@ typedef unsigned int (*ata_xlat_func_t)(struct ata_queued_cmd *qc);
 static struct ata_device *__ata_scsi_find_dev(struct ata_port *ap,
 					const struct scsi_device *scsidev);
 
-#define RW_RECOVERY_MPAGE 0x1
-#define RW_RECOVERY_MPAGE_LEN 12
-#define CACHE_MPAGE 0x8
-#define CACHE_MPAGE_LEN 20
-#define CONTROL_MPAGE 0xa
-#define CONTROL_MPAGE_LEN 12
-#define ALL_MPAGES 0x3f
-#define ALL_SUB_MPAGES 0xff
-
+#define RW_RECOVERY_MPAGE		0x1
+#define RW_RECOVERY_MPAGE_LEN		12
+#define CACHE_MPAGE			0x8
+#define CACHE_MPAGE_LEN			20
+#define CONTROL_MPAGE			0xa
+#define CONTROL_MPAGE_LEN		12
+#define ALL_MPAGES			0x3f
+#define ALL_SUB_MPAGES			0xff
 
 static const u8 def_rw_recovery_mpage[RW_RECOVERY_MPAGE_LEN] = {
 	RW_RECOVERY_MPAGE,
diff --git a/include/linux/ata.h b/include/linux/ata.h
index 0c18499f60b6..b01e2cebe1fe 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -323,15 +323,18 @@ enum {
 	ATA_LOG_SATA_NCQ	= 0x10,
 	ATA_LOG_NCQ_NON_DATA	= 0x12,
 	ATA_LOG_NCQ_SEND_RECV	= 0x13,
+	ATA_LOG_CDL		= 0x18,
+	ATA_LOG_CDL_SIZE	= ATA_SECT_SIZE,
 	ATA_LOG_IDENTIFY_DEVICE	= 0x30,
 	ATA_LOG_CONCURRENT_POSITIONING_RANGES = 0x47,
 
 	/* Identify device log pages: */
+	ATA_LOG_SUPPORTED_CAPABILITIES	= 0x03,
 	ATA_LOG_SECURITY	  = 0x06,
 	ATA_LOG_SATA_SETTINGS	  = 0x08,
 	ATA_LOG_ZONED_INFORMATION = 0x09,
 
-	/* Identify device SATA settings log:*/
+	/* Identify device SATA settings log: */
 	ATA_LOG_DEVSLP_OFFSET	  = 0x30,
 	ATA_LOG_DEVSLP_SIZE	  = 0x08,
 	ATA_LOG_DEVSLP_MDAT	  = 0x00,
diff --git a/include/linux/libata.h b/include/linux/libata.h
index a759dfbdcc91..2b17d6c99a37 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -94,17 +94,18 @@ enum {
 	ATA_DFLAG_DMADIR	= (1 << 10), /* device requires DMADIR */
 	ATA_DFLAG_NCQ_SEND_RECV = (1 << 11), /* device supports NCQ SEND and RECV */
 	ATA_DFLAG_NCQ_PRIO	= (1 << 12), /* device supports NCQ priority */
-	ATA_DFLAG_CFG_MASK	= (1 << 13) - 1,
-
-	ATA_DFLAG_PIO		= (1 << 13), /* device limited to PIO mode */
-	ATA_DFLAG_NCQ_OFF	= (1 << 14), /* device limited to non-NCQ mode */
-	ATA_DFLAG_SLEEPING	= (1 << 15), /* device is sleeping */
-	ATA_DFLAG_DUBIOUS_XFER	= (1 << 16), /* data transfer not verified */
-	ATA_DFLAG_NO_UNLOAD	= (1 << 17), /* device doesn't support unload */
-	ATA_DFLAG_UNLOCK_HPA	= (1 << 18), /* unlock HPA */
-	ATA_DFLAG_INIT_MASK	= (1 << 19) - 1,
-
-	ATA_DFLAG_NCQ_PRIO_ENABLED = (1 << 19), /* Priority cmds sent to dev */
+	ATA_DFLAG_CDL		= (1 << 13), /* supports cmd duration limits */
+	ATA_DFLAG_CFG_MASK	= (1 << 14) - 1,
+
+	ATA_DFLAG_PIO		= (1 << 14), /* device limited to PIO mode */
+	ATA_DFLAG_NCQ_OFF	= (1 << 15), /* device limited to non-NCQ mode */
+	ATA_DFLAG_SLEEPING	= (1 << 16), /* device is sleeping */
+	ATA_DFLAG_DUBIOUS_XFER	= (1 << 17), /* data transfer not verified */
+	ATA_DFLAG_NO_UNLOAD	= (1 << 18), /* device doesn't support unload */
+	ATA_DFLAG_UNLOCK_HPA	= (1 << 19), /* unlock HPA */
+	ATA_DFLAG_INIT_MASK	= (1 << 20) - 1,
+
+	ATA_DFLAG_NCQ_PRIO_ENABLED = (1 << 20), /* Priority cmds sent to dev */
 	ATA_DFLAG_DETACH	= (1 << 24),
 	ATA_DFLAG_DETACHED	= (1 << 25),
 	ATA_DFLAG_DA		= (1 << 26), /* device supports Device Attention */
@@ -115,7 +116,8 @@ enum {
 
 	ATA_DFLAG_FEATURES_MASK	= (ATA_DFLAG_TRUSTED | ATA_DFLAG_DA |	\
 				   ATA_DFLAG_DEVSLP | ATA_DFLAG_NCQ_SEND_RECV | \
-				   ATA_DFLAG_NCQ_PRIO | ATA_DFLAG_FUA),
+				   ATA_DFLAG_NCQ_PRIO | ATA_DFLAG_FUA | \
+				   ATA_DFLAG_CDL),
 
 	ATA_DEV_UNKNOWN		= 0,	/* unknown device */
 	ATA_DEV_ATA		= 1,	/* ATA device */
@@ -709,6 +711,9 @@ struct ata_device {
 	/* Concurrent positioning ranges */
 	struct ata_cpr_log	*cpr_log;
 
+	/* Command Duration Limits log support */
+	u8			cdl[ATA_LOG_CDL_SIZE];
+
 	/* error history */
 	int			spdn_cnt;
 	/* ering is CLEAR_END, read comment above CLEAR_END */
-- 
2.39.0

[PATCH v2 10/18] ata: libata-scsi: handle CDL bits in ata_scsiop_maint_in()

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

For a scsi MAINTENANCE_IN/MI_REPORT_SUPPORTED_OPERATION_CODES operation,
add the translation of the rwcdlp and cdlp bits for the READ16 and
WRITE16 commands. If the ATA device does not support command duration
limits, these bits are always 0. If the ATA device supports command
duration limits, the rwcdlp bit is set to 1 for READ16 and WRITE16 and
the cdlp bits are set to 0x1 for READ16 and 0x2 for WRITE16. These
correspond to the T2A mode page containing the read descriptors and
to the T2B mode page containing the write descriptors, as defined in
SAT-5.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-scsi.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index c64bd3095ea6..b0a6778e852f 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3238,7 +3238,7 @@ static unsigned int ata_scsiop_maint_in(struct ata_scsi_args *args, u8 *rbuf)
 {
 	struct ata_device *dev = args->dev;
 	u8 *cdb = args->cmd->cmnd;
-	u8 supported = 0;
+	u8 supported = 0, cdlp = 0, rwcdlp = 0;
 	unsigned int err = 0;
 
 	if (cdb[2] != 1 && cdb[2] != 3) {
@@ -3265,10 +3265,8 @@ static unsigned int ata_scsiop_maint_in(struct ata_scsi_args *args, u8 *rbuf)
 	case MAINTENANCE_IN:
 	case READ_6:
 	case READ_10:
-	case READ_16:
 	case WRITE_6:
 	case WRITE_10:
-	case WRITE_16:
 	case ATA_12:
 	case ATA_16:
 	case VERIFY:
@@ -3278,6 +3276,28 @@ static unsigned int ata_scsiop_maint_in(struct ata_scsi_args *args, u8 *rbuf)
 	case START_STOP:
 		supported = 3;
 		break;
+	case READ_16:
+		supported = 3;
+		if (dev->flags & ATA_DFLAG_CDL) {
+			/*
+			 * CDL read descriptors map to the T2A page, that is,
+			 * rwcdlp = 0x01 and cdlp = 0x01
+			 */
+			rwcdlp = 0x01;
+			cdlp = 0x01 << 3;
+		}
+		break;
+	case WRITE_16:
+		supported = 3;
+		if (dev->flags & ATA_DFLAG_CDL) {
+			/*
+			 * CDL write descriptors map to the T2B page, that is,
+			 * rwcdlp = 0x01 and cdlp = 0x02
+			 */
+			rwcdlp = 0x01;
+			cdlp = 0x02 << 3;
+		}
+		break;
 	case ZBC_IN:
 	case ZBC_OUT:
 		if (ata_id_zoned_cap(dev->id) ||
@@ -3293,7 +3313,9 @@ static unsigned int ata_scsiop_maint_in(struct ata_scsi_args *args, u8 *rbuf)
 		break;
 	}
 out:
-	rbuf[1] = supported; /* supported */
+	/* One command format */
+	rbuf[0] = rwcdlp;
+	rbuf[1] = cdlp | supported;
 	return err;
 }
 
-- 
2.39.0

[PATCH v2 11/18] ata: libata-scsi: add support for CDL pages mode sense

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Modify ata_scsiop_mode_sense() and ata_msense_control() to support mode
sense access to the T2A and T2B sub-pages of the control mode page.
ata_msense_control() is modified to support sub-pages. The T2A sub-page
is generated using the read descriptors of the command duration limits
log page 18h. The T2B sub-page is generated using the write descriptors
of the same log page. With the addition of these sub-pages, getting all
sub-pages of the control mode page is also supported by increasing the
value of ATA_SCSI_RBUF_SIZE from 576B up to 2048B to ensure that all
sub-pages fit in the fill buffer.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-scsi.c | 150 ++++++++++++++++++++++++++++++++------
 1 file changed, 128 insertions(+), 22 deletions(-)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index b0a6778e852f..91fb19e72856 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -37,7 +37,7 @@
 #include "libata.h"
 #include "libata-transport.h"
 
-#define ATA_SCSI_RBUF_SIZE	576
+#define ATA_SCSI_RBUF_SIZE	2048
 
 static DEFINE_SPINLOCK(ata_scsi_rbuf_lock);
 static u8 ata_scsi_rbuf[ATA_SCSI_RBUF_SIZE];
@@ -55,6 +55,9 @@ static struct ata_device *__ata_scsi_find_dev(struct ata_port *ap,
 #define CONTROL_MPAGE_LEN		12
 #define ALL_MPAGES			0x3f
 #define ALL_SUB_MPAGES			0xff
+#define CDL_T2A_SUB_MPAGE		0x07
+#define CDL_T2B_SUB_MPAGE		0x08
+#define CDL_T2_SUB_MPAGE_LEN		232
 
 static const u8 def_rw_recovery_mpage[RW_RECOVERY_MPAGE_LEN] = {
 	RW_RECOVERY_MPAGE,
@@ -2199,10 +2202,98 @@ static unsigned int ata_msense_caching(u16 *id, u8 *buf, bool changeable)
 	return sizeof(def_cache_mpage);
 }
 
+/*
+ * Simulate MODE SENSE control mode page, sub-page 0.
+ */
+static unsigned int ata_msense_control_spg0(struct ata_device *dev, u8 *buf,
+					    bool changeable)
+{
+	modecpy(buf, def_control_mpage,
+		sizeof(def_control_mpage), changeable);
+	if (changeable) {
+		/* ata_mselect_control() */
+		buf[2] |= (1 << 2);
+	} else {
+		bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
+
+		/* descriptor format sense data */
+		buf[2] |= (d_sense << 2);
+	}
+
+	return sizeof(def_control_mpage);
+}
+
+/*
+ * Translate an ATA duration limit in microseconds to a SCSI duration limit
+ * using the t2cdlunits 0xa (10ms). Since the SCSI duration limits are 2-bytes
+ * only, take care of overflows.
+ */
+static inline u16 ata_xlat_cdl_limit(u8 *buf)
+{
+	u32 limit = get_unaligned_le32(buf);
+
+	return min_t(u32, limit / 10000, 65535);
+}
+
+/*
+ * Simulate MODE SENSE control mode page, sub-pages 07h and 08h
+ * (command duration limits T2A and T2B mode pages).
+ */
+static unsigned int ata_msense_control_spgt2(struct ata_device *dev, u8 *buf,
+					     u8 spg)
+{
+	u8 *b, *cdl = dev->cdl, *desc;
+	u32 policy;
+	int i;
+
+	/*
+	 * Fill the subpage. The first four bytes of the T2A/T2B mode pages
+	 * are a header. The PAGE LENGTH field is the size of the page
+	 * excluding the header.
+	 */
+	buf[0] = CONTROL_MPAGE;
+	buf[1] = spg;
+	put_unaligned_be16(CDL_T2_SUB_MPAGE_LEN - 4, &buf[2]);
+	if (spg == CDL_T2A_SUB_MPAGE) {
+		/*
+		 * Read descriptors map to the T2A page:
+		 * set perf_vs_duration_guidleine.
+		 */
+		buf[7] = (cdl[0] & 0x03) << 4;
+		desc = cdl + 64;
+	} else {
+		/* Write descriptors map to the T2B page */
+		desc = cdl + 288;
+	}
+
+	/* Fill the T2 page descriptors */
+	b = &buf[8];
+	policy = get_unaligned_le32(&cdl[0]);
+	for (i = 0; i < 7; i++, b += 32, desc += 32) {
+		/* t2cdlunits: fixed to 10ms */
+		b[0] = 0x0a;
+
+		/* Max inactive time and its policy */
+		put_unaligned_be16(ata_xlat_cdl_limit(&desc[8]), &b[2]);
+		b[6] = ((policy >> 8) & 0x0f) << 4;
+
+		/* Max active time and its policy */
+		put_unaligned_be16(ata_xlat_cdl_limit(&desc[4]), &b[4]);
+		b[6] |= (policy >> 4) & 0x0f;
+
+		/* Command duration guideline and its policy */
+		put_unaligned_be16(ata_xlat_cdl_limit(&desc[16]), &b[10]);
+		b[14] = policy & 0x0f;
+	}
+
+	return CDL_T2_SUB_MPAGE_LEN;
+}
+
 /**
  *	ata_msense_control - Simulate MODE SENSE control mode page
  *	@dev: ATA device of interest
  *	@buf: output buffer
+ *	@spg: sub-page code
  *	@changeable: whether changeable parameters are requested
  *
  *	Generate a generic MODE SENSE control mode page.
@@ -2211,17 +2302,24 @@ static unsigned int ata_msense_caching(u16 *id, u8 *buf, bool changeable)
  *	None.
  */
 static unsigned int ata_msense_control(struct ata_device *dev, u8 *buf,
-					bool changeable)
+				       u8 spg, bool changeable)
 {
-	modecpy(buf, def_control_mpage, sizeof(def_control_mpage), changeable);
-	if (changeable) {
-		buf[2] |= (1 << 2);	/* ata_mselect_control() */
-	} else {
-		bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
-
-		buf[2] |= (d_sense << 2);	/* descriptor format sense data */
+	unsigned int n;
+
+	switch (spg) {
+	case 0:
+		return ata_msense_control_spg0(dev, buf, changeable);
+	case CDL_T2A_SUB_MPAGE:
+	case CDL_T2B_SUB_MPAGE:
+		return ata_msense_control_spgt2(dev, buf, spg);
+	case ALL_SUB_MPAGES:
+		n = ata_msense_control_spg0(dev, buf, changeable);
+		n += ata_msense_control_spgt2(dev, buf + n, CDL_T2A_SUB_MPAGE);
+		n += ata_msense_control_spgt2(dev, buf + n, CDL_T2A_SUB_MPAGE);
+		return n;
+	default:
+		return 0;
 	}
-	return sizeof(def_control_mpage);
 }
 
 /**
@@ -2294,13 +2392,24 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
 
 	pg = scsicmd[2] & 0x3f;
 	spg = scsicmd[3];
+
 	/*
-	 * No mode subpages supported (yet) but asking for _all_
-	 * subpages may be valid
+	 * Supported subpages: all subpages and sub-pages 07h and 08h of
+	 * the control page.
 	 */
-	if (spg && (spg != ALL_SUB_MPAGES)) {
-		fp = 3;
-		goto invalid_fld;
+	if (spg) {
+		switch (spg) {
+		case ALL_SUB_MPAGES:
+			break;
+		case CDL_T2A_SUB_MPAGE:
+		case CDL_T2B_SUB_MPAGE:
+			if (dev->flags & ATA_DFLAG_CDL && pg == CONTROL_MPAGE)
+				break;
+			fallthrough;
+		default:
+			fp = 3;
+			goto invalid_fld;
+		}
 	}
 
 	switch(pg) {
@@ -2313,13 +2422,13 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
 		break;
 
 	case CONTROL_MPAGE:
-		p += ata_msense_control(args->dev, p, page_control == 1);
+		p += ata_msense_control(args->dev, p, spg, page_control == 1);
 		break;
 
 	case ALL_MPAGES:
 		p += ata_msense_rw_recovery(p, page_control == 1);
 		p += ata_msense_caching(args->id, p, page_control == 1);
-		p += ata_msense_control(args->dev, p, page_control == 1);
+		p += ata_msense_control(args->dev, p, spg, page_control == 1);
 		break;
 
 	default:		/* invalid page code */
@@ -2338,10 +2447,7 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
 			memcpy(rbuf + 4, sat_blk_desc, sizeof(sat_blk_desc));
 		}
 	} else {
-		unsigned int output_len = p - rbuf - 2;
-
-		rbuf[0] = output_len >> 8;
-		rbuf[1] = output_len;
+		put_unaligned_be16(p - rbuf - 2, &rbuf[0]);
 		rbuf[3] |= dpofua;
 		if (ebd) {
 			rbuf[7] = sizeof(sat_blk_desc);
@@ -3640,7 +3746,7 @@ static int ata_mselect_control(struct ata_queued_cmd *qc,
 	/*
 	 * Check that read-only bits are not modified.
 	 */
-	ata_msense_control(dev, mpage, false);
+	ata_msense_control_spg0(dev, mpage, false);
 	for (i = 0; i < CONTROL_MPAGE_LEN - 2; i++) {
 		if (i == 0)
 			continue;
-- 
2.39.0

[PATCH v2 12/18] ata: libata: add ATA feature control sub-page translation

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Add support for the ATA feature control sub-page of the control mode
page to enable/disable the command duration limits feature using the
cdl_ctrl field of the ATA feature control sub-page.

Both mode sense and mode select translation are supported. For mode
sense, the ata device flag ATA_DFLAG_CDL_ENABLED is used to cache the
status of the command duration limits feature. Enabling this feature is
done using a SET FEATURES command with a cdl action set to 1 when the
page cdl_ctrl field value is 0x2 (T2A and T2B pages supported). If this
field is 0, CDL is disabled using the SET FEATURES command with a cdl
action set to 0.

Since a device CDL and NCQ priority features should not be used
simultaneously, ata_mselect_control_ata_feature() returns an error when
attempting to enable CDL with the device priority feature enabled.
Conversely, the function ata_ncq_prio_enable_store() used to enable the
use of the device NCQ priority feature through sysfs is modified to
return an error if the device CDL feature is enabled.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-core.c |  40 ++++++++-
 drivers/ata/libata-sata.c |  11 ++-
 drivers/ata/libata-scsi.c | 167 ++++++++++++++++++++++++++++++++------
 include/linux/ata.h       |   3 +
 include/linux/libata.h    |   1 +
 5 files changed, 193 insertions(+), 29 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 17e32b0a6364..9aa49eab2b95 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2371,13 +2371,15 @@ static void ata_dev_config_cdl(struct ata_device *dev)
 {
 	struct ata_port *ap = dev->link->ap;
 	unsigned int err_mask;
+	bool cdl_enabled;
 	u64 val;
 
 	if (ata_id_major_version(dev->id) < 12)
 		goto not_supported;
 
 	if (!ata_log_supported(dev, ATA_LOG_IDENTIFY_DEVICE) ||
-	    !ata_identify_page_supported(dev, ATA_LOG_SUPPORTED_CAPABILITIES))
+	    !ata_identify_page_supported(dev, ATA_LOG_SUPPORTED_CAPABILITIES) ||
+	    !ata_identify_page_supported(dev, ATA_LOG_CURRENT_SETTINGS))
 		goto not_supported;
 
 	err_mask = ata_read_log_page(dev, ATA_LOG_IDENTIFY_DEVICE,
@@ -2396,6 +2398,40 @@ static void ata_dev_config_cdl(struct ata_device *dev)
 		ata_dev_warn(dev,
 			"Command duration guideline is not supported\n");
 
+	/*
+	 * If CDL is marked as enabled, make sure the feature is enabled too.
+	 * Conversely, if CDL is disabled, make sure the feature is turned off.
+	 */
+	err_mask = ata_read_log_page(dev, ATA_LOG_IDENTIFY_DEVICE,
+				     ATA_LOG_CURRENT_SETTINGS,
+				     ap->sector_buf, 1);
+	if (err_mask)
+		goto not_supported;
+
+	val = get_unaligned_le64(&ap->sector_buf[8]);
+	cdl_enabled = val & BIT_ULL(63) && val & BIT_ULL(21);
+	if (dev->flags & ATA_DFLAG_CDL_ENABLED) {
+		if (!cdl_enabled) {
+			/* Enable CDL on the device */
+			err_mask = ata_dev_set_feature(dev, SETFEATURES_CDL, 1);
+			if (err_mask) {
+				ata_dev_err(dev,
+					    "Enable CDL feature failed\n");
+				goto not_supported;
+			}
+		}
+	} else {
+		if (cdl_enabled) {
+			/* Disable CDL on the device */
+			err_mask = ata_dev_set_feature(dev, SETFEATURES_CDL, 0);
+			if (err_mask) {
+				ata_dev_err(dev,
+					    "Disable CDL feature failed\n");
+				goto not_supported;
+			}
+		}
+	}
+
 	/*
 	 * Command duration limits is supported: cache the CDL log page 18h
 	 * (command duration descriptors).
@@ -2412,7 +2448,7 @@ static void ata_dev_config_cdl(struct ata_device *dev)
 	return;
 
 not_supported:
-	dev->flags &= ~ATA_DFLAG_CDL;
+	dev->flags &= ~(ATA_DFLAG_CDL | ATA_DFLAG_CDL_ENABLED);
 }
 
 static int ata_dev_config_lba(struct ata_device *dev)
diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index 414d7f8a95bf..b12f8e9e1f86 100644
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -907,10 +907,17 @@ static ssize_t ata_ncq_prio_enable_store(struct device *device,
 		goto unlock;
 	}
 
-	if (input)
+	if (input) {
+		if (dev->flags & ATA_DFLAG_CDL_ENABLED) {
+			ata_dev_err(dev,
+				"CDL must be disabled to enable NCQ priority\n");
+			rc = -EINVAL;
+			goto unlock;
+		}
 		dev->flags |= ATA_DFLAG_NCQ_PRIO_ENABLED;
-	else
+	} else {
 		dev->flags &= ~ATA_DFLAG_NCQ_PRIO_ENABLED;
+	}
 
 unlock:
 	spin_unlock_irq(ap->lock);
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 91fb19e72856..0f843512fe04 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -58,6 +58,8 @@ static struct ata_device *__ata_scsi_find_dev(struct ata_port *ap,
 #define CDL_T2A_SUB_MPAGE		0x07
 #define CDL_T2B_SUB_MPAGE		0x08
 #define CDL_T2_SUB_MPAGE_LEN		232
+#define ATA_FEATURE_SUB_MPAGE		0xf2
+#define ATA_FEATURE_SUB_MPAGE_LEN	16
 
 static const u8 def_rw_recovery_mpage[RW_RECOVERY_MPAGE_LEN] = {
 	RW_RECOVERY_MPAGE,
@@ -2289,6 +2291,31 @@ static unsigned int ata_msense_control_spgt2(struct ata_device *dev, u8 *buf,
 	return CDL_T2_SUB_MPAGE_LEN;
 }
 
+/*
+ * Simulate MODE SENSE control mode page, sub-page f2h
+ * (ATA feature control mode page).
+ */
+static unsigned int ata_msense_control_ata_feature(struct ata_device *dev,
+						   u8 *buf)
+{
+	/* PS=0, SPF=1 */
+	buf[0] = CONTROL_MPAGE | (1 << 6);
+	buf[1] = ATA_FEATURE_SUB_MPAGE;
+
+	/*
+	 * The first four bytes of ATA Feature Control mode page are a header.
+	 * The PAGE LENGTH field is the size of the page excluding the header.
+	 */
+	put_unaligned_be16(ATA_FEATURE_SUB_MPAGE_LEN - 4, &buf[2]);
+
+	if (dev->flags & ATA_DFLAG_CDL)
+		buf[4] = 0x02; /* Support T2A and T2B pages */
+	else
+		buf[4] = 0;
+
+	return ATA_FEATURE_SUB_MPAGE_LEN;
+}
+
 /**
  *	ata_msense_control - Simulate MODE SENSE control mode page
  *	@dev: ATA device of interest
@@ -2312,10 +2339,13 @@ static unsigned int ata_msense_control(struct ata_device *dev, u8 *buf,
 	case CDL_T2A_SUB_MPAGE:
 	case CDL_T2B_SUB_MPAGE:
 		return ata_msense_control_spgt2(dev, buf, spg);
+	case ATA_FEATURE_SUB_MPAGE:
+		return ata_msense_control_ata_feature(dev, buf);
 	case ALL_SUB_MPAGES:
 		n = ata_msense_control_spg0(dev, buf, changeable);
 		n += ata_msense_control_spgt2(dev, buf + n, CDL_T2A_SUB_MPAGE);
 		n += ata_msense_control_spgt2(dev, buf + n, CDL_T2A_SUB_MPAGE);
+		n += ata_msense_control_ata_feature(dev, buf + n);
 		return n;
 	default:
 		return 0;
@@ -2394,7 +2424,7 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
 	spg = scsicmd[3];
 
 	/*
-	 * Supported subpages: all subpages and sub-pages 07h and 08h of
+	 * Supported subpages: all subpages and sub-pages 07h, 08h and f2h of
 	 * the control page.
 	 */
 	if (spg) {
@@ -2403,6 +2433,7 @@ static unsigned int ata_scsiop_mode_sense(struct ata_scsi_args *args, u8 *rbuf)
 			break;
 		case CDL_T2A_SUB_MPAGE:
 		case CDL_T2B_SUB_MPAGE:
+		case ATA_FEATURE_SUB_MPAGE:
 			if (dev->flags & ATA_DFLAG_CDL && pg == CONTROL_MPAGE)
 				break;
 			fallthrough;
@@ -3711,20 +3742,11 @@ static int ata_mselect_caching(struct ata_queued_cmd *qc,
 	return 0;
 }
 
-/**
- *	ata_mselect_control - Simulate MODE SELECT for control page
- *	@qc: Storage for translated ATA taskfile
- *	@buf: input buffer
- *	@len: number of valid bytes in the input buffer
- *	@fp: out parameter for the failed field on error
- *
- *	Prepare a taskfile to modify caching information for the device.
- *
- *	LOCKING:
- *	None.
+/*
+ * Simulate MODE SELECT control mode page, sub-page 0.
  */
-static int ata_mselect_control(struct ata_queued_cmd *qc,
-			       const u8 *buf, int len, u16 *fp)
+static int ata_mselect_control_spg0(struct ata_queued_cmd *qc,
+				    const u8 *buf, int len, u16 *fp)
 {
 	struct ata_device *dev = qc->dev;
 	u8 mpage[CONTROL_MPAGE_LEN];
@@ -3762,6 +3784,83 @@ static int ata_mselect_control(struct ata_queued_cmd *qc,
 	return 0;
 }
 
+/*
+ * Translate MODE SELECT control mode page, sub-pages f2h (ATA feature mode
+ * page) into a SET FEATURES command.
+ */
+static unsigned int ata_mselect_control_ata_feature(struct ata_queued_cmd *qc,
+						    const u8 *buf, int len,
+						    u16 *fp)
+{
+	struct ata_device *dev = qc->dev;
+	struct ata_taskfile *tf = &qc->tf;
+	u8 cdl_action;
+
+	/*
+	 * The first four bytes of ATA Feature Control mode page are a header,
+	 * so offsets in mpage are off by 4 compared to buf.  Same for len.
+	 */
+	if (len != ATA_FEATURE_SUB_MPAGE_LEN - 4) {
+		*fp = min(len, ATA_FEATURE_SUB_MPAGE_LEN - 4);
+		return -EINVAL;
+	}
+
+	/* Check cdl_ctrl */
+	switch (buf[0] & 0x03) {
+	case 0:
+		/* Disable CDL */
+		cdl_action = 0;
+		dev->flags &= ~ATA_DFLAG_CDL_ENABLED;
+		break;
+	case 0x02:
+		/* Enable CDL T2A/T2B: NCQ priority must be disabled */
+		if (dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLED) {
+			ata_dev_err(dev,
+				"NCQ priority must be disabled to enable CDL\n");
+			return -EINVAL;
+		}
+		cdl_action = 1;
+		dev->flags |= ATA_DFLAG_CDL_ENABLED;
+		break;
+	default:
+		*fp = 0;
+		return -EINVAL;
+	}
+
+	tf->flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
+	tf->protocol = ATA_PROT_NODATA;
+	tf->command = ATA_CMD_SET_FEATURES;
+	tf->feature = SETFEATURES_CDL;
+	tf->nsect = cdl_action;
+
+	return 1;
+}
+
+/**
+ *	ata_mselect_control - Simulate MODE SELECT for control page
+ *	@qc: Storage for translated ATA taskfile
+ *	@buf: input buffer
+ *	@len: number of valid bytes in the input buffer
+ *	@fp: out parameter for the failed field on error
+ *
+ *	Prepare a taskfile to modify caching information for the device.
+ *
+ *	LOCKING:
+ *	None.
+ */
+static int ata_mselect_control(struct ata_queued_cmd *qc, u8 spg,
+			       const u8 *buf, int len, u16 *fp)
+{
+	switch (spg) {
+	case 0:
+		return ata_mselect_control_spg0(qc, buf, len, fp);
+	case ATA_FEATURE_SUB_MPAGE:
+		return ata_mselect_control_ata_feature(qc, buf, len, fp);
+	default:
+		return -EINVAL;
+	}
+}
+
 /**
  *	ata_scsi_mode_select_xlat - Simulate MODE SELECT 6, 10 commands
  *	@qc: Storage for translated ATA taskfile
@@ -3779,7 +3878,7 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
 	const u8 *cdb = scmd->cmnd;
 	u8 pg, spg;
 	unsigned six_byte, pg_len, hdr_len, bd_len;
-	int len;
+	int len, ret;
 	u16 fp = (u16)-1;
 	u8 bp = 0xff;
 	u8 buffer[64];
@@ -3864,13 +3963,29 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
 	}
 
 	/*
-	 * No mode subpages supported (yet) but asking for _all_
-	 * subpages may be valid
+	 * Supported subpages: all subpages and ATA feature sub-page f2h of
+	 * the control page.
 	 */
-	if (spg && (spg != ALL_SUB_MPAGES)) {
-		fp = (p[0] & 0x40) ? 1 : 0;
-		fp += hdr_len + bd_len;
-		goto invalid_param;
+	if (spg) {
+		switch (spg) {
+		case ALL_SUB_MPAGES:
+			/* All subpages is not supported for the control page */
+			if (pg == CONTROL_MPAGE) {
+				fp = (p[0] & 0x40) ? 1 : 0;
+				fp += hdr_len + bd_len;
+				goto invalid_param;
+			}
+			break;
+		case ATA_FEATURE_SUB_MPAGE:
+			if (qc->dev->flags & ATA_DFLAG_CDL &&
+			    pg == CONTROL_MPAGE)
+				break;
+			fallthrough;
+		default:
+			fp = (p[0] & 0x40) ? 1 : 0;
+			fp += hdr_len + bd_len;
+			goto invalid_param;
+		}
 	}
 	if (pg_len > len)
 		goto invalid_param_len;
@@ -3883,14 +3998,16 @@ static unsigned int ata_scsi_mode_select_xlat(struct ata_queued_cmd *qc)
 		}
 		break;
 	case CONTROL_MPAGE:
-		if (ata_mselect_control(qc, p, pg_len, &fp) < 0) {
+		ret = ata_mselect_control(qc, spg, p, pg_len, &fp);
+		if (ret < 0) {
 			fp += hdr_len + bd_len;
 			goto invalid_param;
-		} else {
-			goto skip; /* No ATA command to send */
 		}
+		if (!ret)
+			goto skip; /* No ATA command to send */
 		break;
-	default:		/* invalid page code */
+	default:
+		/* Invalid page code */
 		fp = bd_len + hdr_len;
 		goto invalid_param;
 	}
diff --git a/include/linux/ata.h b/include/linux/ata.h
index b01e2cebe1fe..a59b17d6ad11 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -330,6 +330,7 @@ enum {
 
 	/* Identify device log pages: */
 	ATA_LOG_SUPPORTED_CAPABILITIES	= 0x03,
+	ATA_LOG_CURRENT_SETTINGS  = 0x04,
 	ATA_LOG_SECURITY	  = 0x06,
 	ATA_LOG_SATA_SETTINGS	  = 0x08,
 	ATA_LOG_ZONED_INFORMATION = 0x09,
@@ -419,6 +420,8 @@ enum {
 	SETFEATURES_SATA_ENABLE = 0x10, /* Enable use of SATA feature */
 	SETFEATURES_SATA_DISABLE = 0x90, /* Disable use of SATA feature */
 
+	SETFEATURES_CDL		= 0x0d, /* Enable/disable cmd duration limits */
+
 	/* SETFEATURE Sector counts for SATA features */
 	SATA_FPDMA_OFFSET	= 0x01,	/* FPDMA non-zero buffer offsets */
 	SATA_FPDMA_AA		= 0x02, /* FPDMA Setup FIS Auto-Activate */
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 2b17d6c99a37..d7fe735e6322 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -106,6 +106,7 @@ enum {
 	ATA_DFLAG_INIT_MASK	= (1 << 20) - 1,
 
 	ATA_DFLAG_NCQ_PRIO_ENABLED = (1 << 20), /* Priority cmds sent to dev */
+	ATA_DFLAG_CDL_ENABLED	= (1 << 21), /* cmd duration limits is enabled */
 	ATA_DFLAG_DETACH	= (1 << 24),
 	ATA_DFLAG_DETACHED	= (1 << 25),
 	ATA_DFLAG_DA		= (1 << 26), /* device supports Device Attention */
-- 
2.39.0

[PATCH v2 13/18] ata: libata: set read/write commands CDL index

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

For devices supporting the command duration limits feature, when a read
or write operation has the IOPRIO_CLASS_DL priority class and the
command duration limits feature is enabled, set the command duration
limit index field of the command to the priority level.

For unqueued read and write operations, the command duration limit index
is set as the lower 2 bits of the feature field. For queued NCQ
read/write commands, the index is set as the lower 2 bits of the
auxiliary field.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-core.c | 43 ++++++++++++++++++++++++++++++++++-----
 drivers/ata/libata-scsi.c |  3 +--
 drivers/ata/libata.h      |  2 +-
 include/linux/libata.h    |  1 +
 4 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 9aa49eab2b95..2c1531ef169d 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -665,13 +665,37 @@ u64 ata_tf_read_block(const struct ata_taskfile *tf, struct ata_device *dev)
 	return block;
 }
 
+/*
+ * Set a taskfile CDL index.
+ */
+static inline void ata_set_tf_cdl(struct ata_queued_cmd *qc, int ioprio)
+{
+	struct ata_taskfile *tf = &qc->tf;
+	int cdl;
+
+	if (IOPRIO_PRIO_CLASS(ioprio) != IOPRIO_CLASS_DL)
+		return;
+
+	cdl = IOPRIO_PRIO_DATA(ioprio) & 0x07;
+	if (!cdl)
+		return;
+
+	if (tf->protocol == ATA_PROT_NCQ)
+		tf->auxiliary |= cdl;
+	else
+		tf->feature |= cdl;
+
+	/* Mark this command as having a CDL */
+	qc->flags |= ATA_QCFLAG_HAS_CDL;
+}
+
 /**
  *	ata_build_rw_tf - Build ATA taskfile for given read/write request
  *	@qc: Metadata associated with the taskfile to build
  *	@block: Block address
  *	@n_block: Number of blocks
  *	@tf_flags: RW/FUA etc...
- *	@class: IO priority class
+ *	@ioprio: IO priority class and level
  *
  *	LOCKING:
  *	None.
@@ -685,7 +709,7 @@ u64 ata_tf_read_block(const struct ata_taskfile *tf, struct ata_device *dev)
  *	-EINVAL if the request is invalid.
  */
 int ata_build_rw_tf(struct ata_queued_cmd *qc, u64 block, u32 n_block,
-		    unsigned int tf_flags, int class)
+		    unsigned int tf_flags, int ioprio)
 {
 	struct ata_taskfile *tf = &qc->tf;
 	struct ata_device *dev = qc->dev;
@@ -722,13 +746,22 @@ int ata_build_rw_tf(struct ata_queued_cmd *qc, u64 block, u32 n_block,
 			tf->device |= 1 << 7;
 
 		if (dev->flags & ATA_DFLAG_NCQ_PRIO_ENABLED &&
-		    class == IOPRIO_CLASS_RT)
+		    IOPRIO_PRIO_CLASS(ioprio) == IOPRIO_CLASS_RT)
 			tf->hob_nsect |= ATA_PRIO_HIGH << ATA_SHIFT_PRIO;
+
+		if (dev->flags & ATA_DFLAG_CDL_ENABLED)
+			ata_set_tf_cdl(qc, ioprio);
+
 	} else if (dev->flags & ATA_DFLAG_LBA) {
 		tf->flags |= ATA_TFLAG_LBA;
 
-		/* We need LBA48 for FUA writes */
-		if (!(tf->flags & ATA_TFLAG_FUA) && lba_28_ok(block, n_block)) {
+		if (dev->flags & ATA_DFLAG_CDL_ENABLED)
+			ata_set_tf_cdl(qc, ioprio);
+
+		/* Both FUA writes and a CDL index require 48-bit commands */
+		if (!(tf->flags & ATA_TFLAG_FUA) &&
+		    !(qc->flags & ATA_QCFLAG_HAS_CDL) &&
+		    lba_28_ok(block, n_block)) {
 			/* use LBA28 */
 			tf->device |= (block >> 24) & 0xf;
 		} else if (lba_48_ok(block, n_block)) {
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 0f843512fe04..b8caecd875cd 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1549,7 +1549,6 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
 	struct scsi_cmnd *scmd = qc->scsicmd;
 	const u8 *cdb = scmd->cmnd;
 	struct request *rq = scsi_cmd_to_rq(scmd);
-	int class = IOPRIO_PRIO_CLASS(req_get_ioprio(rq));
 	unsigned int tf_flags = 0;
 	u64 block;
 	u32 n_block;
@@ -1625,7 +1624,7 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
 	qc->flags |= ATA_QCFLAG_IO;
 	qc->nbytes = n_block * scmd->device->sector_size;
 
-	rc = ata_build_rw_tf(qc, block, n_block, tf_flags, class);
+	rc = ata_build_rw_tf(qc, block, n_block, tf_flags, req_get_ioprio(rq));
 	if (likely(rc == 0))
 		return 0;
 
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index 5481d29bb273..339b19c0bbcf 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -45,7 +45,7 @@ static inline void ata_force_cbl(struct ata_port *ap) { }
 extern u64 ata_tf_to_lba(const struct ata_taskfile *tf);
 extern u64 ata_tf_to_lba48(const struct ata_taskfile *tf);
 extern int ata_build_rw_tf(struct ata_queued_cmd *qc, u64 block, u32 n_block,
-			   unsigned int tf_flags, int class);
+			   unsigned int tf_flags, int ioprio);
 extern u64 ata_tf_read_block(const struct ata_taskfile *tf,
 			     struct ata_device *dev);
 extern unsigned ata_exec_internal(struct ata_device *dev,
diff --git a/include/linux/libata.h b/include/linux/libata.h
index d7fe735e6322..ab8b62036c12 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -209,6 +209,7 @@ enum {
 	ATA_QCFLAG_CLEAR_EXCL	= (1 << 5), /* clear excl_link on completion */
 	ATA_QCFLAG_QUIET	= (1 << 6), /* don't report device error */
 	ATA_QCFLAG_RETRY	= (1 << 7), /* retry after failure */
+	ATA_QCFLAG_HAS_CDL	= (1 << 8), /* qc has CDL a descriptor set */
 
 	ATA_QCFLAG_EH		= (1 << 16), /* cmd aborted and owned by EH */
 	ATA_QCFLAG_SENSE_VALID	= (1 << 17), /* sense data valid */
-- 
2.39.0

[PATCH v2 14/18] scsi: sd: detect support for command duration limits

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Detect if a disk supports command duration limits. Support for
the READ 16, WRITE 16, READ 32 and WRITE 32 commands is tested using
the function scsi_report_opcode(). For a disk supporting command
duration limits, the mode page indicating the command duration limits
descriptors that apply to the command is indicated using the rwcdlp
and cdlp bits.

Support duration limits is advertizes through sysfs using the new
"duration_limits" sysfs sub-directory of the generic device directory,
that is, /sys/block/sdX/device/duration_limits. Within this new
directory, the limit descriptors that apply to read and write operations
are exposed within the read and write directories, with descriptor
attributes grouped together in directories. The overall sysfs structure
created is:

/sys/block/sde/device/duration_limits/
├── perf_vs_duration_guideline
├── read
│   ├── 1
│   │   ├── duration_guideline
│   │   ├── duration_guideline_policy
│   │   ├── max_active_time
│   │   ├── max_active_time_policy
│   │   ├── max_inactive_time
│   │   └── max_inactive_time_policy
│   ├── 2
│   │   ├── duration_guideline
...
│   └── page
└── write
    ├── 1
    │   ├── duration_guideline
    │   ├── duration_guideline_policy
...

For each of the read and write descriptor directories, the page
attribute file indicate the command duration limit page providing the
descriptors. The possible values for the page attribute are "A", "B",
"T2A" and "T2B".

The new "duration_limits" attributes directory is added only for disks
that supports command duration limits.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/scsi/Makefile |   2 +-
 drivers/scsi/sd.c     |   2 +
 drivers/scsi/sd.h     |  61 ++++
 drivers/scsi/sd_cdl.c | 764 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 828 insertions(+), 1 deletion(-)
 create mode 100644 drivers/scsi/sd_cdl.c

diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index f055bfd54a68..0e48cb6d21d6 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -170,7 +170,7 @@ scsi_mod-$(CONFIG_BLK_DEV_BSG)	+= scsi_bsg.o
 
 hv_storvsc-y			:= storvsc_drv.o
 
-sd_mod-objs	:= sd.o
+sd_mod-objs	:= sd.o sd_cdl.o
 sd_mod-$(CONFIG_BLK_DEV_INTEGRITY) += sd_dif.o
 sd_mod-$(CONFIG_BLK_DEV_ZONED) += sd_zbc.o
 
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 2b56ff4fcf8a..45ff44a73256 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3306,6 +3306,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
 		sd_read_write_same(sdkp, buffer);
 		sd_read_security(sdkp, buffer);
 		sd_config_protection(sdkp);
+		sd_read_cdl(sdkp, buffer);
 	}
 
 	/*
@@ -3626,6 +3627,7 @@ static void scsi_disk_release(struct device *dev)
 
 	ida_free(&sd_index_ida, sdkp->index);
 	sd_zbc_free_zone_info(sdkp);
+	sd_cdl_release(sdkp);
 	put_device(&sdkp->device->sdev_gendev);
 	free_opal_dev(sdkp->opal_dev);
 
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 5eea762f84d1..e60d33bd222a 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -81,6 +81,62 @@ struct zoned_disk_info {
 	u32		zone_blocks;
 };
 
+/*
+ * Command duration limits sub-pages for the control mode page 0Ah.
+ */
+enum sd_cdlp {
+	SD_CDLP_A,
+	SD_CDLP_B,
+	SD_CDLP_T2A,
+	SD_CDLP_T2B,
+	SD_CDLP_NONE,
+
+	SD_CDL_MAX_PAGES = SD_CDLP_NONE,
+};
+
+enum sd_cdl_cmd {
+	SD_CDL_READ_16,
+	SD_CDL_WRITE_16,
+	SD_CDL_READ_32,
+	SD_CDL_WRITE_32,
+
+	SD_CDL_CMD_MAX,
+};
+
+enum sd_cdl_rw {
+	SD_CDL_READ,
+	SD_CDL_WRITE,
+	SD_CDL_RW,
+};
+
+struct sd_cdl_desc {
+	struct kobject	kobj;
+	u64		max_inactive_time;
+	u64		max_active_time;
+	u64		duration;
+	u8		max_inactive_policy;
+	u8		max_active_policy;
+	u8		duration_policy;
+	u8		cdlp;
+};
+
+#define SD_CDL_MAX_DESC		7
+
+struct sd_cdl_page {
+	struct kobject		kobj;
+	bool			sysfs_registered;
+	enum sd_cdl_rw		rw;
+	enum sd_cdlp		cdlp;
+	struct sd_cdl_desc      descs[SD_CDL_MAX_DESC];
+};
+
+struct sd_cdl {
+	struct kobject		kobj;
+	bool			sysfs_registered;
+	u8			perf_vs_duration_guideline;
+	struct sd_cdl_page	pages[SD_CDL_RW];
+};
+
 struct scsi_disk {
 	struct scsi_device *device;
 
@@ -131,6 +187,7 @@ struct scsi_disk {
 	u8		provisioning_mode;
 	u8		zeroing_mode;
 	u8		nr_actuators;		/* Number of actuators */
+	struct sd_cdl	*cdl;
 	unsigned	ATO : 1;	/* state of disk ATO bit */
 	unsigned	cache_override : 1; /* temp override of WCE,RCD */
 	unsigned	WCE : 1;	/* state of disk WCE bit */
@@ -295,4 +352,8 @@ static inline blk_status_t sd_zbc_prepare_zone_append(struct scsi_cmnd *cmd,
 void sd_print_sense_hdr(struct scsi_disk *sdkp, struct scsi_sense_hdr *sshdr);
 void sd_print_result(const struct scsi_disk *sdkp, const char *msg, int result);
 
+/* Command duration limits support (in sd_cdl.c) */
+void sd_read_cdl(struct scsi_disk *sdkp, unsigned char *buf);
+void sd_cdl_release(struct scsi_disk *sdkp);
+
 #endif /* _SCSI_DISK_H */
diff --git a/drivers/scsi/sd_cdl.c b/drivers/scsi/sd_cdl.c
new file mode 100644
index 000000000000..513cd989f19a
--- /dev/null
+++ b/drivers/scsi/sd_cdl.c
@@ -0,0 +1,764 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SCSI Command Duration Limits (CDL)
+ *
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ */
+#include <linux/vmalloc.h>
+#include <linux/mutex.h>
+
+#include <asm/unaligned.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+
+#include "sd.h"
+
+/*
+ * Command duration limits sub-pages for the control mode page 0Ah.
+ */
+static const struct sd_cdlp_info {
+	u8	subpage;
+	char	*name;
+} cdl_page[SD_CDL_MAX_PAGES + 1] = {
+	{ 0x03,	"A"	},
+	{ 0x04,	"B"	},
+	{ 0x07,	"T2A"	},
+	{ 0x08,	"T2B"	},
+	{ 0x00,	"none"	},
+};
+
+static const struct sd_cdl_cmd_info {
+	u8	opcode;
+	u16	sa;
+	char	*name;
+} cdl_cmd[SD_CDL_CMD_MAX] = {
+	{ READ_16,		0,		"READ_16"	},
+	{ WRITE_16,		0,		"WRITE_16"	},
+	{ VARIABLE_LENGTH_CMD,	READ_32,	"READ_32"	},
+	{ VARIABLE_LENGTH_CMD,	WRITE_32,	"WRITE_32"	},
+};
+
+static const char *sd_cdl_perf_name(u8 val)
+{
+	switch (val) {
+	case 0x00:
+		return "0";
+	case 0x01:
+		return "0.5";
+	case 0x02:
+		return "1.0";
+	case 0x03:
+		return "1.5";
+	case 0x04:
+		return "2.0";
+	case 0x05:
+		return "2.5";
+	case 0x06:
+		return "3";
+	case 0x07:
+		return "4";
+	case 0x08:
+		return "5";
+	case 0x09:
+		return "8";
+	case 0x0A:
+		return "10";
+	case 0x0B:
+		return "15";
+	case 0x0C:
+		return "20";
+	default:
+		return "?";
+	}
+}
+
+static const char *sd_cdl_policy_name(u8 policy)
+{
+	switch (policy) {
+	case 0x00:
+		return "complete-earliest";
+	case 0x01:
+		return "continue-next-limit";
+	case 0x02:
+		return "continue-no-limit";
+	case 0x0d:
+		return "complete-unavailable";
+	case 0x0e:
+		return "abort-recovery";
+	case 0x0f:
+		return "abort";
+	default:
+		return "?";
+	}
+}
+
+/*
+ * Command duration limits descriptors sysfs plumbing.
+ */
+struct sd_cdl_desc_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(struct sd_cdl_desc *desc, char *buf);
+};
+
+#define CDL_DESC_ATTR_RO(_name)	\
+	static struct sd_cdl_desc_sysfs_entry				\
+	cdl_desc_##_name##_entry = {					\
+		.attr	= { .name = __stringify(_name), .mode = 0444 },	\
+		.show	= cdl_desc_##_name##_show,			\
+	}
+
+static ssize_t cdl_desc_max_inactive_time_show(struct sd_cdl_desc *desc,
+					       char *buf)
+{
+	return sysfs_emit(buf, "%llu\n", desc->max_inactive_time);
+}
+CDL_DESC_ATTR_RO(max_inactive_time);
+
+static ssize_t cdl_desc_max_inactive_time_policy_show(struct sd_cdl_desc *desc,
+						      char *buf)
+{
+	return sysfs_emit(buf, "%s\n",
+			sd_cdl_policy_name(desc->max_inactive_policy));
+}
+CDL_DESC_ATTR_RO(max_inactive_time_policy);
+
+static ssize_t cdl_desc_max_active_time_show(struct sd_cdl_desc *desc,
+					     char *buf)
+{
+	return sysfs_emit(buf, "%llu\n", desc->max_active_time);
+}
+CDL_DESC_ATTR_RO(max_active_time);
+
+static ssize_t cdl_desc_max_active_time_policy_show(struct sd_cdl_desc *desc,
+						    char *buf)
+{
+	return sysfs_emit(buf, "%s\n",
+			sd_cdl_policy_name(desc->max_active_policy));
+}
+CDL_DESC_ATTR_RO(max_active_time_policy);
+
+static ssize_t cdl_desc_duration_guideline_show(struct sd_cdl_desc *desc,
+						char *buf)
+{
+	return sysfs_emit(buf, "%llu\n", desc->duration);
+}
+CDL_DESC_ATTR_RO(duration_guideline);
+
+static ssize_t cdl_desc_duration_guideline_policy_show(struct sd_cdl_desc *desc,
+						       char *buf)
+{
+	return sysfs_emit(buf, "%s\n",
+		sd_cdl_policy_name(desc->duration_policy));
+}
+CDL_DESC_ATTR_RO(duration_guideline_policy);
+
+static umode_t sd_cdl_desc_attr_visible(struct kobject *kobj,
+					struct attribute *attr, int n)
+{
+	struct sd_cdl_desc *desc = container_of(kobj, struct sd_cdl_desc, kobj);
+
+	/*
+	 * Descriptors in pages A and B only have the duration guideline
+	 * field.
+	 */
+	if ((desc->cdlp == SD_CDLP_A || desc->cdlp == SD_CDLP_B) &&
+	    (attr != &cdl_desc_duration_guideline_entry.attr))
+		return 0;
+
+	return attr->mode;
+}
+
+static struct attribute *sd_cdl_desc_attrs[] = {
+	&cdl_desc_max_inactive_time_entry.attr,
+	&cdl_desc_max_inactive_time_policy_entry.attr,
+	&cdl_desc_max_active_time_entry.attr,
+	&cdl_desc_max_active_time_policy_entry.attr,
+	&cdl_desc_duration_guideline_entry.attr,
+	&cdl_desc_duration_guideline_policy_entry.attr,
+	NULL,
+};
+
+static const struct attribute_group sd_cdl_desc_group = {
+	.attrs = sd_cdl_desc_attrs,
+	.is_visible = sd_cdl_desc_attr_visible,
+};
+__ATTRIBUTE_GROUPS(sd_cdl_desc);
+
+static ssize_t sd_cdl_desc_sysfs_show(struct kobject *kobj,
+				      struct attribute *attr, char *buf)
+{
+	struct sd_cdl_desc_sysfs_entry *entry =
+		container_of(attr, struct sd_cdl_desc_sysfs_entry, attr);
+	struct sd_cdl_desc *desc = container_of(kobj, struct sd_cdl_desc, kobj);
+
+	return entry->show(desc, buf);
+}
+
+static const struct sysfs_ops sd_cdl_desc_sysfs_ops = {
+	.show	= sd_cdl_desc_sysfs_show,
+};
+
+static void sd_cdl_sysfs_nop_release(struct kobject *kobj) { }
+
+static struct kobj_type sd_cdl_desc_ktype = {
+	.sysfs_ops	= &sd_cdl_desc_sysfs_ops,
+	.default_groups	= sd_cdl_desc_groups,
+	.release	= sd_cdl_sysfs_nop_release,
+};
+
+/*
+ * Duration limits page sysfs plumbing.
+ */
+struct sd_cdl_page_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(struct sd_cdl_page *page, char *buf);
+};
+
+#define CDL_PAGE_ATTR_RO(_name)	\
+	static struct sd_cdl_page_sysfs_entry				\
+	cdl_page_##_name##_entry = {					\
+		.attr	= { .name = __stringify(_name), .mode = 0444 },	\
+		.show	= cdl_page_##_name##_show,			\
+	}
+
+static ssize_t cdl_page_page_show(struct sd_cdl_page *page, char *buf)
+{
+	return sysfs_emit(buf, "%s\n", cdl_page[page->cdlp].name);
+}
+CDL_PAGE_ATTR_RO(page);
+
+static struct attribute *sd_cdl_page_attrs[] = {
+	&cdl_page_page_entry.attr,
+	NULL,
+};
+
+static const struct attribute_group sd_cdl_page_group = {
+	.attrs = sd_cdl_page_attrs,
+};
+__ATTRIBUTE_GROUPS(sd_cdl_page);
+
+static ssize_t sd_cdl_page_sysfs_show(struct kobject *kobj,
+				      struct attribute *attr, char *buf)
+{
+	struct sd_cdl_page_sysfs_entry *entry =
+		container_of(attr, struct sd_cdl_page_sysfs_entry, attr);
+	struct sd_cdl_page *page = container_of(kobj, struct sd_cdl_page, kobj);
+
+	return entry->show(page, buf);
+}
+
+static const struct sysfs_ops sd_cdl_page_sysfs_ops = {
+	.show	= sd_cdl_page_sysfs_show,
+};
+
+static struct kobj_type sd_cdl_page_ktype = {
+	.sysfs_ops	= &sd_cdl_page_sysfs_ops,
+	.default_groups	= sd_cdl_page_groups,
+	.release	= sd_cdl_sysfs_nop_release,
+};
+
+static void sd_cdl_sysfs_unregister_page(struct sd_cdl_page *page)
+{
+	int i;
+
+	for (i = 0; i < SD_CDL_MAX_DESC; i++) {
+		if (page->sysfs_registered)
+			kobject_del(&page->descs[i].kobj);
+		kobject_put(&page->descs[i].kobj);
+	}
+	if (page->sysfs_registered)
+		kobject_del(&page->kobj);
+	kobject_put(&page->kobj);
+
+	page->cdlp = SD_CDLP_NONE;
+	page->sysfs_registered = false;
+}
+
+static int sd_cdl_sysfs_register_page(struct scsi_disk *sdkp,
+				      struct sd_cdl_page *page)
+{
+	int i, ret;
+
+	/*
+	 * If the page is already registered, the updated page descriptors
+	 * are already exported.
+	 */
+	if (page->sysfs_registered)
+		return 0;
+
+	ret = kobject_add(&page->kobj, &sdkp->cdl->kobj,
+			  "%s", page->rw ? "write" : "read");
+	if (ret) {
+		kobject_put(&page->kobj);
+		return ret;
+	}
+
+	for (i = 0; i < SD_CDL_MAX_DESC; i++) {
+		ret = kobject_add(&page->descs[i].kobj, &page->kobj,
+				  "%d", i + 1);
+		if (ret) {
+			int j;
+
+			kobject_put(&page->descs[i].kobj);
+			for (j = 0; j < SD_CDL_MAX_DESC; j++) {
+				if (j < i)
+					kobject_del(&page->descs[j].kobj);
+				kobject_put(&page->descs[j].kobj);
+			}
+			kobject_del(&page->kobj);
+			kobject_put(&page->kobj);
+			return ret;
+		}
+	}
+
+	page->sysfs_registered = true;
+
+	return 0;
+}
+
+/*
+ * Command duration limits sysfs plumbing, top level (duration limits directory
+ * under the "device" sysfs directory.
+ */
+struct sd_cdl_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(struct sd_cdl *cdl, char *buf);
+};
+
+#define CDL_ATTR_RO(_name)	\
+	static struct sd_cdl_sysfs_entry cdl_##_name##_entry = {	\
+		.attr	= { .name = __stringify(_name), .mode = 0444 },	\
+		.show	= cdl_##_name##_show,				\
+	}
+
+static ssize_t cdl_perf_vs_duration_guideline_show(struct sd_cdl *cdl,
+						   char *buf)
+{
+	return sysfs_emit(buf, "%s\n",
+			  sd_cdl_perf_name(cdl->perf_vs_duration_guideline));
+}
+CDL_ATTR_RO(perf_vs_duration_guideline);
+
+static struct attribute *sd_cdl_attrs[] = {
+	&cdl_perf_vs_duration_guideline_entry.attr,
+	NULL,
+};
+
+static umode_t sd_cdl_attr_visible(struct kobject *kobj,
+				   struct attribute *attr, int n)
+{
+	struct sd_cdl *cdl = container_of(kobj, struct sd_cdl, kobj);
+
+	/* perf_vs_duration_guideline exists only if page T2A is supported */
+	if (attr == &cdl_perf_vs_duration_guideline_entry.attr &&
+	    cdl->pages[SD_CDL_READ].cdlp != SD_CDLP_T2A &&
+	    cdl->pages[SD_CDL_WRITE].cdlp != SD_CDLP_T2A)
+		return 0;
+
+	return attr->mode;
+}
+
+static const struct attribute_group sd_cdl_group = {
+	.attrs		= sd_cdl_attrs,
+	.is_visible	= sd_cdl_attr_visible,
+};
+__ATTRIBUTE_GROUPS(sd_cdl);
+
+static ssize_t sd_cdl_sysfs_show(struct kobject *kobj,
+				 struct attribute *attr, char *page)
+{
+	struct sd_cdl_sysfs_entry *entry =
+		container_of(attr, struct sd_cdl_sysfs_entry, attr);
+	struct sd_cdl *cdl = container_of(kobj, struct sd_cdl, kobj);
+
+	return entry->show(cdl, page);
+}
+
+static const struct sysfs_ops sd_cdl_sysfs_ops = {
+	.show	= sd_cdl_sysfs_show,
+};
+
+static void sd_cdl_sysfs_release(struct kobject *kobj)
+{
+	struct sd_cdl *cdl = container_of(kobj, struct sd_cdl, kobj);
+
+	kfree(cdl);
+}
+
+static struct kobj_type sd_cdl_ktype = {
+	.sysfs_ops	= &sd_cdl_sysfs_ops,
+	.default_groups	= sd_cdl_groups,
+	.release	= sd_cdl_sysfs_release,
+};
+
+static void sd_cdl_sysfs_unregister(struct scsi_disk *sdkp)
+{
+	struct sd_cdl *cdl = NULL;
+	int i;
+
+	swap(sdkp->cdl, cdl);
+	if (!cdl)
+		return;
+
+	if (!cdl->sysfs_registered) {
+		kfree(cdl);
+		return;
+	}
+
+	for (i = 0; i < SD_CDL_RW; i++) {
+		if (cdl->pages[i].sysfs_registered)
+			sd_cdl_sysfs_unregister_page(&cdl->pages[i]);
+	}
+
+	kobject_del(&cdl->kobj);
+	kobject_put(&cdl->kobj);
+}
+
+static void sd_cdl_sysfs_register(struct scsi_disk *sdkp)
+{
+	struct scsi_device *sdev = sdkp->device;
+	struct sd_cdl *cdl = sdkp->cdl;
+	struct sd_cdl_page *page;
+	int i, ret;
+
+	if (!cdl->sysfs_registered) {
+		ret = kobject_add(&cdl->kobj, &sdev->sdev_gendev.kobj,
+				  "duration_limits");
+		if (ret) {
+			kobject_put(&cdl->kobj);
+			goto unregister;
+		}
+
+		cdl->sysfs_registered = true;
+	}
+
+	/* Check if the pages changed */
+	for (i = 0; i < SD_CDL_RW; i++) {
+		page = &cdl->pages[i];
+		if (page->cdlp == SD_CDLP_NONE) {
+			sd_cdl_sysfs_unregister_page(page);
+			continue;
+		}
+
+		ret = sd_cdl_sysfs_register_page(sdkp, page);
+		if (ret) {
+			page->cdlp = SD_CDLP_NONE;
+			goto unregister;
+		}
+	}
+
+	return;
+
+unregister:
+	sd_cdl_sysfs_unregister(sdkp);
+}
+
+/*
+ * CDL pages A and B time limits in microseconds.
+ */
+static u64 sd_cdl_time(u8 *buf, u8 cdlunit)
+{
+	u64 val = get_unaligned_be16(buf);
+	u64 factor;
+
+	switch (cdlunit) {
+	case 0x00:
+		return 0;
+	case 0x04:
+		/* 1 microsecond */
+		factor = NSEC_PER_USEC;
+		break;
+	case 0x05:
+		/* 10 milliseconds */
+		factor = 10ULL * USEC_PER_MSEC;
+		break;
+	case 0x06:
+		/* 500 milliseconds */
+		factor = 500ULL * USEC_PER_MSEC;
+		break;
+	default:
+		return 0;
+	}
+
+	return val * factor;
+}
+
+/*
+ * CDL pages T2A and T2B time limits in microseconds.
+ */
+static u64 sd_cdl_t2time(u8 *buf, u8 t2cdlunits)
+{
+	u64 val = get_unaligned_be16(buf);
+	u64 factor;
+
+	switch (t2cdlunits) {
+	case 0x00:
+		return 0;
+	case 0x06:
+		/* 500 nanoseconds */
+		factor = 500;
+		break;
+	case 0x08:
+		/* 1 microsecond */
+		factor = NSEC_PER_USEC;
+		break;
+	case 0x0A:
+		/* 10 milliseconds */
+		factor = 10ULL * NSEC_PER_MSEC;
+		break;
+	case 0x0E:
+		/* 500 milliseconds */
+		factor = 500ULL * NSEC_PER_MSEC;
+		break;
+	default:
+		return 0;
+	}
+
+	val *= factor;
+	do_div(val, NSEC_PER_USEC);
+
+	return val;
+}
+
+static int sd_cdl_read_page(struct scsi_disk *sdkp, struct sd_cdl_page *page,
+			    unsigned char *buf)
+{
+	struct sd_cdl *cdl = sdkp->cdl;
+	struct sd_cdl_desc *desc = &page->descs[0];
+	u8 cdlp = page->cdlp;
+	struct scsi_mode_data data;
+	int i, ret;
+
+	ret = scsi_mode_sense(sdkp->device, 0x08, 0x0a, cdl_page[cdlp].subpage,
+			      buf, SD_BUF_SIZE, SD_TIMEOUT, sdkp->max_retries,
+			      &data, NULL);
+	if (ret) {
+		sd_printk(KERN_ERR, sdkp,
+			  "Command duration limits: read CDL page %s failed\n",
+			  cdl_page[cdlp].name);
+		return ret;
+	}
+	buf += data.header_length + data.block_descriptor_length;
+
+	if (cdlp == SD_CDLP_A || cdlp == SD_CDLP_B) {
+		buf += 8;
+
+		for (i = 0; i < SD_CDL_MAX_DESC; i++, buf += 4, desc++) {
+			u8 cdlunit = (buf[0] & 0xe0) >> 5;
+
+			desc->duration = sd_cdl_time(&buf[2], cdlunit);
+			desc->cdlp = cdlp;
+		}
+	} else {
+		/* T2A and T2B limits page */
+		if (cdlp == SD_CDLP_T2A)
+			cdl->perf_vs_duration_guideline = buf[7] >> 4;
+
+		buf += 8;
+
+		for (i = 0; i < SD_CDL_MAX_DESC; i++, buf += 32, desc++) {
+			u8 t2cdlunits = buf[0] & 0x0f;
+
+			desc->max_inactive_time =
+				sd_cdl_t2time(&buf[2], t2cdlunits);
+			desc->max_active_time =
+				sd_cdl_t2time(&buf[4], t2cdlunits);
+			desc->duration =
+				sd_cdl_t2time(&buf[10], t2cdlunits);
+			desc->max_inactive_policy =  (buf[6] >> 4) & 0x0f;
+			desc->max_active_policy = buf[6] & 0x0f;
+			desc->duration_policy = buf[14] & 0x0f;
+			desc->cdlp = cdlp;
+		}
+	}
+
+	return 0;
+}
+
+static int sd_cdl_read_pages(struct scsi_disk *sdkp, enum sd_cdlp *rw_cdlp,
+			     unsigned char *buf)
+{
+	struct sd_cdl *cdl = sdkp->cdl;
+	struct sd_cdl_page *page;
+	int i, ret;
+
+	/* Read supported pages */
+	for (i = 0; i < SD_CDL_RW; i++) {
+		page = &cdl->pages[i];
+		page->cdlp = rw_cdlp[i];
+		if (page->cdlp == SD_CDLP_NONE)
+			continue;
+
+		ret = sd_cdl_read_page(sdkp, page, buf);
+		if (ret) {
+			page->cdlp = SD_CDLP_NONE;
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static u8 sd_cdl_check_cmd_support(struct scsi_disk *sdkp,
+				   enum sd_cdl_cmd cmd, unsigned char *buf)
+{
+	u8 opcode = cdl_cmd[cmd].opcode;
+	u16 sa = cdl_cmd[cmd].sa;
+	u8 cdlp;
+
+	/*
+	 * READ 32 and WRITE 32 are used only for disks that also support
+	 * type 2 data protection. If the disk does not have such feature,
+	 * ignore these commands.
+	 */
+	if ((sa == READ_32 || sa == WRITE_32) &&
+	    sdkp->protection_type != T10_PI_TYPE2_PROTECTION)
+		return SD_CDLP_NONE;
+
+	/* Check operation code */
+	if (scsi_report_opcode(sdkp->device, buf, SD_BUF_SIZE, opcode, sa) < 0)
+		return SD_CDLP_NONE;
+
+	if ((buf[1] & 0x03) != 0x03)
+		return SD_CDLP_NONE;
+
+	/* See SPC-6, one command format of REPORT SUPPORTED OPERATION CODES */
+	cdlp = (buf[1] & 0x18) >> 3;
+	if (buf[0] & 0x01) {
+		/* rwcdlp == 1 */
+		switch (cdlp) {
+		case 0x01:
+			return SD_CDLP_T2A;
+		case 0x02:
+			return SD_CDLP_T2B;
+		}
+	} else {
+		/* rwcdlp == 0 */
+		switch (cdlp) {
+		case 0x01:
+			return SD_CDLP_A;
+		case 0x02:
+			return SD_CDLP_B;
+		}
+	}
+
+	return SD_CDLP_NONE;
+}
+
+static bool sd_cdl_supported(struct scsi_disk *sdkp, enum sd_cdlp *rw_cdlp,
+			     unsigned char *buf)
+{
+	enum sd_cdlp cmd_cdlp[SD_CDL_CMD_MAX];
+	int i;
+
+	/*
+	 * Command duration limits is supported for READ 16, WRITE 16,
+	 * READ 32 and WRITE 32. Go through all these commands one at a time
+	 * and check if any support duration limits.
+	 */
+	for (i = 0; i < SD_CDL_CMD_MAX; i++)
+		cmd_cdlp[i] = sd_cdl_check_cmd_support(sdkp, i, buf);
+
+	/*
+	 * Allow support only for drives that report the same CDL page for the
+	 * read 16 and 32 variants and the same page for the write 16 and 32
+	 * variants.
+	 */
+	if (cmd_cdlp[SD_CDL_READ_32] != SD_CDLP_NONE &&
+	    cmd_cdlp[SD_CDL_READ_16] != SD_CDLP_NONE) {
+		if (cmd_cdlp[SD_CDL_READ_32] != cmd_cdlp[SD_CDL_READ_16])
+			rw_cdlp[SD_CDL_READ] = SD_CDLP_NONE;
+		else
+			rw_cdlp[SD_CDL_READ] = cmd_cdlp[SD_CDL_READ_16];
+	} else {
+		rw_cdlp[SD_CDL_READ] = cmd_cdlp[SD_CDL_READ_16];
+	}
+
+	if (cmd_cdlp[SD_CDL_WRITE_32] != SD_CDLP_NONE &&
+	    cmd_cdlp[SD_CDL_WRITE_16] != SD_CDLP_NONE) {
+		if (cmd_cdlp[SD_CDL_WRITE_32] != cmd_cdlp[SD_CDL_WRITE_16])
+			rw_cdlp[SD_CDL_WRITE] = SD_CDLP_NONE;
+		else
+			rw_cdlp[SD_CDL_WRITE] = cmd_cdlp[SD_CDL_WRITE_16];
+	} else {
+		rw_cdlp[SD_CDL_WRITE] = cmd_cdlp[SD_CDL_WRITE_16];
+	}
+
+	return rw_cdlp[SD_CDL_READ] != SD_CDLP_NONE ||
+		rw_cdlp[SD_CDL_WRITE] != SD_CDLP_NONE;
+}
+
+static struct sd_cdl *sd_cdl_alloc(void)
+{
+	struct sd_cdl *cdl;
+	struct sd_cdl_page *page;
+	int i, j;
+
+	cdl = kzalloc(sizeof(struct sd_cdl), GFP_KERNEL);
+	if (!cdl)
+		return NULL;
+
+	kobject_init(&cdl->kobj, &sd_cdl_ktype);
+	for (i = 0; i < SD_CDL_RW; i++) {
+		page = &cdl->pages[i];
+		kobject_init(&page->kobj, &sd_cdl_page_ktype);
+		page->rw = i;
+		page->cdlp = SD_CDLP_NONE;
+		for (j = 0; j < SD_CDL_MAX_DESC; j++)
+			kobject_init(&page->descs[j].kobj, &sd_cdl_desc_ktype);
+	}
+
+	return cdl;
+}
+
+void sd_read_cdl(struct scsi_disk *sdkp, unsigned char *buf)
+{
+	struct sd_cdl *cdl = sdkp->cdl;
+	enum sd_cdlp rw_cdlp[SD_CDL_RW];
+
+	/*
+	 * Check for CDL support. If the disk does not support duration limits,
+	 * clear any support information that was previously registered.
+	 */
+	if (!sd_cdl_supported(sdkp, rw_cdlp, buf))
+		goto unregister;
+
+	if (!cdl) {
+		cdl = sd_cdl_alloc();
+		if (!cdl)
+			return;
+	}
+
+	/*
+	 * We have CDL support: force the use of READ16/WRITE16.
+	 * READ32 and WRITE32 will be used automatically for disks with
+	 * T10_PI_TYPE2_PROTECTION support.
+	 */
+	sdkp->device->use_16_for_rw = 1;
+	sdkp->device->use_10_for_rw = 0;
+
+	if (!sdkp->cdl) {
+		sd_printk(KERN_NOTICE, sdkp,
+			"Command duration limits supported, reads: %s, writes: %s\n",
+			cdl_page[rw_cdlp[SD_CDL_READ]].name,
+			cdl_page[rw_cdlp[SD_CDL_WRITE]].name);
+		sdkp->cdl = cdl;
+	}
+
+	/* Update duration limits descriptor pages */
+	if (sd_cdl_read_pages(sdkp, rw_cdlp, buf))
+		goto unregister;
+
+	sd_cdl_sysfs_register(sdkp);
+
+	return;
+
+unregister:
+	sd_cdl_sysfs_unregister(sdkp);
+}
+
+void sd_cdl_release(struct scsi_disk *sdkp)
+{
+	sd_cdl_sysfs_unregister(sdkp);
+}
-- 
2.39.0

[PATCH v2 15/18] scsi: sd: set read/write commands CDL index

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Introduce the command duration limits helper function
sd_cdl_cmd_limit() to retrieve and set the DLD bits of the
READ/WRITE 16 and READ/WRITE 32 commands to indicate to the device
the command duration limit descriptor to apply to the command.

When command duration limits are enabled, sd_cdl_cmd_limit() obtains the
index of the descriptor to apply to the command for requests that have
the IOPRIO_CLASS_DL priority class with a priority data sepcifying a
valid descriptor index (1 to 7).

The read-write sysfs attribute "enable" is introduced to control
setting the command duration limits indexes. If this attribute is set
to 0 (default), command duration limits specified by the user are
ignored. The user must set this attribute to 1 for command duration
limits to be set. Enabling and disabling the command duration limits
feature for ATA devices must be done using the ATA feature sub-page of
the control mode page. The sd_cdl_enable() function is introduced to
check if this mode page is supported by the device and if it is, use
it to enable/disable CDL.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/scsi/sd.c     |  16 +++--
 drivers/scsi/sd.h     |  10 ++++
 drivers/scsi/sd_cdl.c | 134 +++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 152 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 45ff44a73256..1f516910da0b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1042,13 +1042,14 @@ static blk_status_t sd_setup_flush_cmnd(struct scsi_cmnd *cmd)
 
 static blk_status_t sd_setup_rw32_cmnd(struct scsi_cmnd *cmd, bool write,
 				       sector_t lba, unsigned int nr_blocks,
-				       unsigned char flags)
+				       unsigned char flags, unsigned int dld)
 {
 	cmd->cmd_len = SD_EXT_CDB_SIZE;
 	cmd->cmnd[0]  = VARIABLE_LENGTH_CMD;
 	cmd->cmnd[7]  = 0x18; /* Additional CDB len */
 	cmd->cmnd[9]  = write ? WRITE_32 : READ_32;
 	cmd->cmnd[10] = flags;
+	cmd->cmnd[11] = dld & 0x07;
 	put_unaligned_be64(lba, &cmd->cmnd[12]);
 	put_unaligned_be32(lba, &cmd->cmnd[20]); /* Expected Indirect LBA */
 	put_unaligned_be32(nr_blocks, &cmd->cmnd[28]);
@@ -1058,12 +1059,12 @@ static blk_status_t sd_setup_rw32_cmnd(struct scsi_cmnd *cmd, bool write,
 
 static blk_status_t sd_setup_rw16_cmnd(struct scsi_cmnd *cmd, bool write,
 				       sector_t lba, unsigned int nr_blocks,
-				       unsigned char flags)
+				       unsigned char flags, unsigned int dld)
 {
 	cmd->cmd_len  = 16;
 	cmd->cmnd[0]  = write ? WRITE_16 : READ_16;
-	cmd->cmnd[1]  = flags;
-	cmd->cmnd[14] = 0;
+	cmd->cmnd[1]  = flags | ((dld >> 2) & 0x01);
+	cmd->cmnd[14] = (dld & 0x03) << 6;
 	cmd->cmnd[15] = 0;
 	put_unaligned_be64(lba, &cmd->cmnd[2]);
 	put_unaligned_be32(nr_blocks, &cmd->cmnd[10]);
@@ -1126,6 +1127,7 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
 	unsigned int mask = logical_to_sectors(sdp, 1) - 1;
 	bool write = rq_data_dir(rq) == WRITE;
 	unsigned char protect, fua;
+	unsigned int dld = 0;
 	blk_status_t ret;
 	unsigned int dif;
 	bool dix;
@@ -1175,6 +1177,8 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
 	fua = rq->cmd_flags & REQ_FUA ? 0x8 : 0;
 	dix = scsi_prot_sg_count(cmd);
 	dif = scsi_host_dif_capable(cmd->device->host, sdkp->protection_type);
+	if (sd_cdl_enabled(sdkp))
+		dld = sd_cdl_dld(sdkp, cmd);
 
 	if (dif || dix)
 		protect = sd_setup_protect_cmnd(cmd, dix, dif);
@@ -1183,10 +1187,10 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
 
 	if (protect && sdkp->protection_type == T10_PI_TYPE2_PROTECTION) {
 		ret = sd_setup_rw32_cmnd(cmd, write, lba, nr_blocks,
-					 protect | fua);
+					 protect | fua, dld);
 	} else if (sdp->use_16_for_rw || (nr_blocks > 0xffff)) {
 		ret = sd_setup_rw16_cmnd(cmd, write, lba, nr_blocks,
-					 protect | fua);
+					 protect | fua, dld);
 	} else if ((nr_blocks > 0xff) || (lba > 0x1fffff) ||
 		   sdp->use_10_for_rw || protect) {
 		ret = sd_setup_rw10_cmnd(cmd, write, lba, nr_blocks,
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index e60d33bd222a..5b6b6dc4b92d 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -130,8 +130,11 @@ struct sd_cdl_page {
 	struct sd_cdl_desc      descs[SD_CDL_MAX_DESC];
 };
 
+struct scsi_disk;
+
 struct sd_cdl {
 	struct kobject		kobj;
+	struct scsi_disk	*sdkp;
 	bool			sysfs_registered;
 	u8			perf_vs_duration_guideline;
 	struct sd_cdl_page	pages[SD_CDL_RW];
@@ -188,6 +191,7 @@ struct scsi_disk {
 	u8		zeroing_mode;
 	u8		nr_actuators;		/* Number of actuators */
 	struct sd_cdl	*cdl;
+	unsigned	cdl_enabled : 1;
 	unsigned	ATO : 1;	/* state of disk ATO bit */
 	unsigned	cache_override : 1; /* temp override of WCE,RCD */
 	unsigned	WCE : 1;	/* state of disk WCE bit */
@@ -355,5 +359,11 @@ void sd_print_result(const struct scsi_disk *sdkp, const char *msg, int result);
 /* Command duration limits support (in sd_cdl.c) */
 void sd_read_cdl(struct scsi_disk *sdkp, unsigned char *buf);
 void sd_cdl_release(struct scsi_disk *sdkp);
+int sd_cdl_dld(struct scsi_disk *sdkp, struct scsi_cmnd *scmd);
+
+static inline bool sd_cdl_enabled(struct scsi_disk *sdkp)
+{
+	return sdkp->cdl && sdkp->cdl_enabled;
+}
 
 #endif /* _SCSI_DISK_H */
diff --git a/drivers/scsi/sd_cdl.c b/drivers/scsi/sd_cdl.c
index 513cd989f19a..59d02dbb5ea1 100644
--- a/drivers/scsi/sd_cdl.c
+++ b/drivers/scsi/sd_cdl.c
@@ -93,6 +93,63 @@ static const char *sd_cdl_policy_name(u8 policy)
 	}
 }
 
+/*
+ * Enable/disable CDL.
+ */
+static int sd_cdl_enable(struct scsi_disk *sdkp, bool enable)
+{
+	struct scsi_device *sdp = sdkp->device;
+	struct scsi_mode_data data;
+	struct scsi_sense_hdr sshdr;
+	struct scsi_vpd *vpd;
+	bool is_ata = false;
+	char buf[64];
+	int ret;
+
+	rcu_read_lock();
+	vpd = rcu_dereference(sdp->vpd_pg89);
+	if (vpd)
+		is_ata = true;
+	rcu_read_unlock();
+
+	/*
+	 * For ATA devices, CDL needs to be enabled with a SET FEATURES command.
+	 */
+	if (is_ata) {
+		char *buf_data;
+		int len;
+
+		ret = scsi_mode_sense(sdp, 0x08, 0x0a, 0xf2, buf, sizeof(buf),
+				      SD_TIMEOUT, sdkp->max_retries, &data,
+				      NULL);
+		if (ret)
+			return -EINVAL;
+
+		/* Enable CDL using the ATA feature page */
+		len = min_t(size_t, sizeof(buf),
+			    data.length - data.header_length -
+			    data.block_descriptor_length);
+		buf_data = buf + data.header_length +
+			data.block_descriptor_length;
+		if (enable)
+			buf_data[4] = 0x02;
+		else
+			buf_data[4] = 0;
+
+		ret = scsi_mode_select(sdp, 1, 0, buf_data, len, SD_TIMEOUT,
+				       sdkp->max_retries, &data, &sshdr);
+		if (ret) {
+			if (scsi_sense_valid(&sshdr))
+				sd_print_sense_hdr(sdkp, &sshdr);
+			return -EINVAL;
+		}
+	}
+
+	sdkp->cdl_enabled = enable;
+
+	return 0;
+}
+
 /*
  * Command duration limits descriptors sysfs plumbing.
  */
@@ -324,6 +381,7 @@ static int sd_cdl_sysfs_register_page(struct scsi_disk *sdkp,
 struct sd_cdl_sysfs_entry {
 	struct attribute attr;
 	ssize_t (*show)(struct sd_cdl *cdl, char *buf);
+	ssize_t (*store)(struct sd_cdl *cdl, const char *buf, size_t length);
 };
 
 #define CDL_ATTR_RO(_name)	\
@@ -332,6 +390,13 @@ struct sd_cdl_sysfs_entry {
 		.show	= cdl_##_name##_show,				\
 	}
 
+#define CDL_ATTR_RW(_name)	\
+	static struct sd_cdl_sysfs_entry cdl_##_name##_entry = {	\
+		.attr	= { .name = __stringify(_name), .mode = 0644 },	\
+		.show	= cdl_##_name##_show,				\
+		.store	= cdl_##_name##_store,				\
+	}
+
 static ssize_t cdl_perf_vs_duration_guideline_show(struct sd_cdl *cdl,
 						   char *buf)
 {
@@ -340,8 +405,31 @@ static ssize_t cdl_perf_vs_duration_guideline_show(struct sd_cdl *cdl,
 }
 CDL_ATTR_RO(perf_vs_duration_guideline);
 
+static ssize_t cdl_enable_show(struct sd_cdl *cdl, char *buf)
+{
+	return sysfs_emit(buf, "%d\n", (int)cdl->sdkp->cdl_enabled);
+}
+
+static ssize_t cdl_enable_store(struct sd_cdl *cdl,
+				const char *buf, size_t count)
+{
+	int ret;
+	bool v;
+
+	if (kstrtobool(buf, &v))
+		return -EINVAL;
+
+	ret = sd_cdl_enable(cdl->sdkp, v);
+	if (ret)
+		return ret;
+
+	return count;
+}
+CDL_ATTR_RW(enable);
+
 static struct attribute *sd_cdl_attrs[] = {
 	&cdl_perf_vs_duration_guideline_entry.attr,
+	&cdl_enable_entry.attr,
 	NULL,
 };
 
@@ -375,8 +463,25 @@ static ssize_t sd_cdl_sysfs_show(struct kobject *kobj,
 	return entry->show(cdl, page);
 }
 
+static ssize_t sd_cdl_sysfs_store(struct kobject *kobj, struct attribute *attr,
+				  const char *buf, size_t length)
+{
+	struct sd_cdl_sysfs_entry *entry =
+		container_of(attr, struct sd_cdl_sysfs_entry, attr);
+	struct sd_cdl *cdl = container_of(kobj, struct sd_cdl, kobj);
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (!entry->store)
+		return -EIO;
+
+	return entry->store(cdl, buf, length);
+}
+
 static const struct sysfs_ops sd_cdl_sysfs_ops = {
 	.show	= sd_cdl_sysfs_show,
+	.store	= sd_cdl_sysfs_store,
 };
 
 static void sd_cdl_sysfs_release(struct kobject *kobj)
@@ -411,6 +516,7 @@ static void sd_cdl_sysfs_unregister(struct scsi_disk *sdkp)
 			sd_cdl_sysfs_unregister_page(&cdl->pages[i]);
 	}
 
+	cdl->sdkp->cdl_enabled = 0;
 	kobject_del(&cdl->kobj);
 	kobject_put(&cdl->kobj);
 }
@@ -689,7 +795,7 @@ static bool sd_cdl_supported(struct scsi_disk *sdkp, enum sd_cdlp *rw_cdlp,
 		rw_cdlp[SD_CDL_WRITE] != SD_CDLP_NONE;
 }
 
-static struct sd_cdl *sd_cdl_alloc(void)
+static struct sd_cdl *sd_cdl_alloc(struct scsi_disk *sdkp)
 {
 	struct sd_cdl *cdl;
 	struct sd_cdl_page *page;
@@ -699,6 +805,7 @@ static struct sd_cdl *sd_cdl_alloc(void)
 	if (!cdl)
 		return NULL;
 
+	cdl->sdkp = sdkp;
 	kobject_init(&cdl->kobj, &sd_cdl_ktype);
 	for (i = 0; i < SD_CDL_RW; i++) {
 		page = &cdl->pages[i];
@@ -725,7 +832,7 @@ void sd_read_cdl(struct scsi_disk *sdkp, unsigned char *buf)
 		goto unregister;
 
 	if (!cdl) {
-		cdl = sd_cdl_alloc();
+		cdl = sd_cdl_alloc(sdkp);
 		if (!cdl)
 			return;
 	}
@@ -762,3 +869,26 @@ void sd_cdl_release(struct scsi_disk *sdkp)
 {
 	sd_cdl_sysfs_unregister(sdkp);
 }
+
+/*
+ * Check if a command has a duration limit set. If it does, return the
+ * descriptor index to use and 0 if the command has no limit set.
+ */
+int sd_cdl_dld(struct scsi_disk *sdkp, struct scsi_cmnd *scmd)
+{
+	unsigned int ioprio = req_get_ioprio(scsi_cmd_to_rq(scmd));
+	unsigned int dld;
+
+	/*
+	 * Use "no limit" if the request ioprio class is not IOPRIO_CLASS_DL
+	 * or if the user specified an invalid CDL descriptor index.
+	 */
+	if (IOPRIO_PRIO_CLASS(ioprio) != IOPRIO_CLASS_DL)
+		return 0;
+
+	dld = IOPRIO_PRIO_DATA(ioprio);
+	if (dld > SD_CDL_MAX_DESC)
+		return 0;
+
+	return dld;
+}
-- 
2.39.0

[PATCH v2 16/18] scsi: sd: handle read/write CDL timeout failures

[Niklas Cassel]

Commands using a duration limit descriptor that has limit policies set
to a value other than 0x0 may be failed by the device if one of the
limits are exceeded. For such commands, since the failure is the result
of the user duration limit configuration and workload, the commands
should not be retried and terminated immediately. Furthermore, to allow
the user to differentiate these "soft" failures from hard errors due to
hardware problem, a different error code than EIO should be returned.

There are 2 cases to consider:
(1) The failure is due to a limit policy failing the command with a
check condition sense key, that is, any limit policy other than 0xD.
For this case, scsi_check_sense() is modified to detect failures with
the ABORTED COMMAND sense key and the COMMAND TIMEOUT BEFORE PROCESSING
or COMMAND TIMEOUT DURING PROCESSING or COMMAND TIMEOUT DURING
PROCESSING DUE TO ERROR RECOVERY additional sense code. For these
failures, a SUCCESS disposition is returned so that
scsi_finish_command() is called to terminate the command.

(2) The failure is due to a limit policy set to 0xD, which result in the
command being terminated with a GOOD status, COMPLETED sense key, and
DATA CURRENTLY UNAVAILABLE additional sense code. To handle this case,
the scsi_check_sense() is modified to return a SUCCESS disposition so
that scsi_finish_command() is called to terminate the command.
In addition, scsi_decide_disposition() has to be modified to see if a
command being terminated with GOOD status has sense data.
This is as defined in SCSI Primary Commands - 6 (SPC-6), so all
according to spec, even if GOOD status commands were not checked before.

If scsi_check_sense() detects sense data representing a duration limit,
scsi_check_sense() will set the newly introduced SCSI ML byte
SCSIML_STAT_DL_TIMEOUT. This SCSI ML byte is checked in
scsi_noretry_cmd(), so that a command that failed because of a CDL
timeout cannot be retried. The SCSI ML byte is also checked in
scsi_result_to_blk_status() to complete the command request with the
BLK_STS_DURATION_LIMIT status, which result in the user seeing ETIME
errors for the failed commands.

Co-developed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/scsi/scsi_error.c | 46 +++++++++++++++++++++++++++++++++++++++
 drivers/scsi/scsi_lib.c   |  4 ++++
 drivers/scsi/scsi_priv.h  |  1 +
 3 files changed, 51 insertions(+)

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 51aa5c1e31b5..e7103bf3ab23 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -536,6 +536,7 @@ static inline void set_scsi_ml_byte(struct scsi_cmnd *cmd, u8 status)
  */
 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;
 
@@ -595,6 +596,22 @@ enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
 		if (sshdr.asc == 0x10) /* DIF */
 			return SUCCESS;
 
+		/*
+		 * Check aborts due to command duration limit policy:
+		 * ABORTED COMMAND additional sense code with the
+		 * COMMAND TIMEOUT BEFORE PROCESSING or
+		 * COMMAND TIMEOUT DURING PROCESSING or
+		 * COMMAND TIMEOUT DURING PROCESSING DUE TO ERROR RECOVERY
+		 * additional sense code qualifiers.
+		 */
+		if (sshdr.asc == 0x2e &&
+		    sshdr.ascq >= 0x01 && sshdr.ascq <= 0x03) {
+			set_scsi_ml_byte(scmd, SCSIML_STAT_DL_TIMEOUT);
+			req->cmd_flags |= REQ_FAILFAST_DEV;
+			req->rq_flags |= RQF_QUIET;
+			return SUCCESS;
+		}
+
 		if (sshdr.asc == 0x44 && sdev->sdev_bflags & BLIST_RETRY_ITF)
 			return ADD_TO_MLQUEUE;
 		if (sshdr.asc == 0xc1 && sshdr.ascq == 0x01 &&
@@ -691,6 +708,15 @@ enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
 		}
 		return SUCCESS;
 
+	case COMPLETED:
+		if (sshdr.asc == 0x55 && sshdr.ascq == 0x0a) {
+			set_scsi_ml_byte(scmd, SCSIML_STAT_DL_TIMEOUT);
+			req->cmd_flags |= REQ_FAILFAST_DEV;
+			req->rq_flags |= RQF_QUIET;
+			return SUCCESS;
+		}
+		return SUCCESS;
+
 	default:
 		return SUCCESS;
 	}
@@ -785,6 +811,14 @@ static enum scsi_disposition scsi_eh_completed_normally(struct scsi_cmnd *scmd)
 	switch (get_status_byte(scmd)) {
 	case SAM_STAT_GOOD:
 		scsi_handle_queue_ramp_up(scmd->device);
+		if (scmd->sense_buffer && SCSI_SENSE_VALID(scmd))
+			/*
+			 * If we have sense data, call scsi_check_sense() in
+			 * order to set the correct SCSI ML byte (if any).
+			 * No point in checking the return value, since the
+			 * command has already completed successfully.
+			 */
+			scsi_check_sense(scmd);
 		fallthrough;
 	case SAM_STAT_COMMAND_TERMINATED:
 		return SUCCESS;
@@ -1807,6 +1841,10 @@ bool scsi_noretry_cmd(struct scsi_cmnd *scmd)
 		return !!(req->cmd_flags & REQ_FAILFAST_DRIVER);
 	}
 
+	/* Never retry commands aborted due to a duration limit timeout */
+	if (scsi_ml_byte(scmd->result) == SCSIML_STAT_DL_TIMEOUT)
+		return true;
+
 	if (!scsi_status_is_check_condition(scmd->result))
 		return false;
 
@@ -1966,6 +2004,14 @@ enum scsi_disposition scsi_decide_disposition(struct scsi_cmnd *scmd)
 		if (scmd->cmnd[0] == REPORT_LUNS)
 			scmd->device->sdev_target->expecting_lun_change = 0;
 		scsi_handle_queue_ramp_up(scmd->device);
+		if (scmd->sense_buffer && SCSI_SENSE_VALID(scmd))
+			/*
+			 * If we have sense data, call scsi_check_sense() in
+			 * order to set the correct SCSI ML byte (if any).
+			 * No point in checking the return value, since the
+			 * command has already completed successfully.
+			 */
+			scsi_check_sense(scmd);
 		fallthrough;
 	case SAM_STAT_COMMAND_TERMINATED:
 		return SUCCESS;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 79cece5eff5d..5923873f09e5 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -602,6 +602,8 @@ static blk_status_t scsi_result_to_blk_status(int result)
 		return BLK_STS_MEDIUM;
 	case SCSIML_STAT_TGT_FAILURE:
 		return BLK_STS_TARGET;
+	case SCSIML_STAT_DL_TIMEOUT:
+		return BLK_STS_DURATION_LIMIT;
 	}
 
 	switch (host_byte(result)) {
@@ -799,6 +801,8 @@ static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
 				blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
 			}
 			break;
+		case COMPLETED:
+			fallthrough;
 		default:
 			action = ACTION_FAIL;
 			break;
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index 74324fba4281..f42388ecb024 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -27,6 +27,7 @@ enum scsi_ml_status {
 	SCSIML_STAT_NOSPC		= 0x02,	/* Space allocation on the dev failed */
 	SCSIML_STAT_MED_ERROR		= 0x03,	/* Medium error */
 	SCSIML_STAT_TGT_FAILURE		= 0x04,	/* Permanent target failure */
+	SCSIML_STAT_DL_TIMEOUT		= 0x05, /* Command Duration Limit timeout */
 };
 
 static inline u8 scsi_ml_byte(int result)
-- 
2.39.0

[PATCH v2 17/18] ata: libata: handle completion of CDL commands using policy 0xD

[Niklas Cassel]

A CDL timeout for policy 0xF is defined as a NCQ error, just with a CDL
specific sk/asc/ascq in the sense data. Therefore, the existing code in
libata does not need to be modified to handle a policy 0xF CDL timeout.

For Command Duration Limits policy 0xD:
The device shall complete the command without error with the additional
sense code set to DATA CURRENTLY UNAVAILABLE.

Since a CDL timeout for policy 0xD is not an error, we cannot use the
NCQ Command Error log (10h).

Instead, we need to read the Sense Data for Successful NCQ Commands
log (0Fh).

In the success case, just like in the error case, we cannot simply read
a log page from the interrupt handler itself, since reading a log page
involves sending a READ LOG DMA EXT or READ LOG EXT command.

Therefore, we add a new EH action ATA_EH_GET_SUCCESS_SENSE.
When a command completes without error, and when the ATA_SENSE bit
is set, this new action is set as pending, and EH is scheduled.

This way, similar to the NCQ error case, the log page will be read
from EH context.

An alternative would have been to add a new kthread or workqueue to
handle this. However, extending EH can be done with minimal changes
and avoids the need to synchronize a new kthread/workqueue with EH.

Co-developed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 drivers/ata/libata-core.c |  88 ++++++++++++++++++++++++++++++-
 drivers/ata/libata-eh.c   | 108 +++++++++++++++++++++++++++++++++++++-
 drivers/ata/libata-sata.c |  89 +++++++++++++++++++++++++++++++
 include/linux/ata.h       |   3 ++
 include/linux/libata.h    |  11 +++-
 5 files changed, 295 insertions(+), 4 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 2c1531ef169d..e46258dfaa8e 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -685,8 +685,12 @@ static inline void ata_set_tf_cdl(struct ata_queued_cmd *qc, int ioprio)
 	else
 		tf->feature |= cdl;
 
-	/* Mark this command as having a CDL */
-	qc->flags |= ATA_QCFLAG_HAS_CDL;
+	/*
+	 * Mark this command as having a CDL and request the result
+	 * task file so that we can inspect the sense data available
+	 * bit on completion.
+	 */
+	qc->flags |= ATA_QCFLAG_HAS_CDL | ATA_QCFLAG_RESULT_TF;
 }
 
 /**
@@ -2431,6 +2435,24 @@ static void ata_dev_config_cdl(struct ata_device *dev)
 		ata_dev_warn(dev,
 			"Command duration guideline is not supported\n");
 
+	/*
+	 * We must have support for the sense data for successful NCQ commands
+	 * log indicated by the successful NCQ command sense data supported bit.
+	 */
+	val = get_unaligned_le64(&ap->sector_buf[8]);
+	if (!(val & BIT_ULL(63)) || !(val & BIT_ULL(47))) {
+		ata_dev_warn(dev,
+			"CDL supported but Successful NCQ Command Sense Data is not supported\n");
+		goto not_supported;
+	}
+
+	/* Without NCQ autosense, the successful NCQ commands log is useless. */
+	if (!ata_id_has_ncq_autosense(dev->id)) {
+		ata_dev_warn(dev,
+			"CDL supported but NCQ autosense is not supported\n");
+		goto not_supported;
+	}
+
 	/*
 	 * If CDL is marked as enabled, make sure the feature is enabled too.
 	 * Conversely, if CDL is disabled, make sure the feature is turned off.
@@ -2465,6 +2487,35 @@ static void ata_dev_config_cdl(struct ata_device *dev)
 		}
 	}
 
+	/*
+	 * While CDL itself has to be enabled using sysfs, CDL requires that
+	 * sense data for successful NCQ commands is enabled to work properly.
+	 * Just like ata_dev_config_sense_reporting(), enable it unconditionally
+	 * if supported.
+	 */
+	if (!(val & BIT_ULL(63)) || !(val & BIT_ULL(18))) {
+		err_mask = ata_dev_set_feature(dev,
+					SETFEATURE_SENSE_DATA_SUCC_NCQ, 0x1);
+		if (err_mask) {
+			ata_dev_warn(dev,
+				     "failed to enable Sense Data for successful NCQ commands, Emask 0x%x\n",
+				     err_mask);
+			goto not_supported;
+		}
+	}
+
+	/*
+	 * Allocate a buffer to handle reading the sense data for successful
+	 * NCQ Commands log page for commands using a CDL with one of the limit
+	 * policy set to 0xD (successful completion with sense data available
+	 * bit set).
+	 */
+	if (!ap->ncq_sense_buf) {
+		ap->ncq_sense_buf = kmalloc(ATA_LOG_SENSE_NCQ_SIZE, GFP_KERNEL);
+		if (!ap->ncq_sense_buf)
+			goto not_supported;
+	}
+
 	/*
 	 * Command duration limits is supported: cache the CDL log page 18h
 	 * (command duration descriptors).
@@ -2482,6 +2533,8 @@ static void ata_dev_config_cdl(struct ata_device *dev)
 
 not_supported:
 	dev->flags &= ~(ATA_DFLAG_CDL | ATA_DFLAG_CDL_ENABLED);
+	kfree(ap->ncq_sense_buf);
+	ap->ncq_sense_buf = NULL;
 }
 
 static int ata_dev_config_lba(struct ata_device *dev)
@@ -4882,6 +4935,36 @@ void ata_qc_complete(struct ata_queued_cmd *qc)
 			fill_result_tf(qc);
 
 		trace_ata_qc_complete_done(qc);
+
+		/*
+		 * For CDL commands that completed without an error, check if
+		 * we have sense data (ATA_SENSE is set). If we do, then the
+		 * command may have been aborted by the device due to a limit
+		 * timeout using the policy 0xD. For these commands, invoke EH
+		 * to get the command sense data.
+		 */
+		if (qc->result_tf.status & ATA_SENSE &&
+		    ((ata_is_ncq(qc->tf.protocol) &&
+		      dev->flags & ATA_DFLAG_CDL_ENABLED) ||
+		     (!(ata_is_ncq(qc->tf.protocol) &&
+			ata_id_sense_reporting_enabled(dev->id))))) {
+			/*
+			 * Tell SCSI EH to not overwrite scmd->result even if
+			 * this command is finished with result SAM_STAT_GOOD.
+			 */
+			qc->scsicmd->flags |= SCMD_EH_SUCCESS_CMD;
+			qc->flags |= ATA_QCFLAG_EH_SUCCESS_CMD;
+			ehi->dev_action[dev->devno] |= ATA_EH_GET_SUCCESS_SENSE;
+
+			/*
+			 * set pending so that ata_qc_schedule_eh() does not
+			 * trigger fast drain, and freeze the port.
+			 */
+			ap->pflags |= ATA_PFLAG_EH_PENDING;
+			ata_qc_schedule_eh(qc);
+			return;
+		}
+
 		/* Some commands need post-processing after successful
 		 * completion.
 		 */
@@ -5514,6 +5597,7 @@ static void ata_host_release(struct kref *kref)
 
 		kfree(ap->pmp_link);
 		kfree(ap->slave_link);
+		kfree(ap->ncq_sense_buf);
 		kfree(ap);
 		host->ports[i] = NULL;
 	}
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 1c3d55fc1cae..c1d08753301c 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1913,6 +1913,102 @@ static inline bool ata_eh_quiet(struct ata_queued_cmd *qc)
 	return qc->flags & ATA_QCFLAG_QUIET;
 }
 
+static int ata_eh_read_sense_success_non_ncq(struct ata_link *link)
+{
+	struct ata_port *ap = link->ap;
+	struct ata_queued_cmd *qc;
+
+	qc = __ata_qc_from_tag(ap, link->active_tag);
+	if (!qc)
+		return -EIO;
+
+	if (!(qc->flags & ATA_QCFLAG_EH) ||
+	    !(qc->flags & ATA_QCFLAG_EH_SUCCESS_CMD) ||
+	    qc->err_mask)
+		return -EIO;
+
+	ata_eh_request_sense(qc, false);
+
+	if (!(qc->flags & ATA_QCFLAG_SENSE_VALID))
+		return -EIO;
+
+	/*
+	 * If we have sense data, call scsi_check_sense() in order to set the
+	 * correct SCSI ML byte (if any). No point in checking the return value,
+	 * since the command has already completed successfully.
+	 */
+	scsi_check_sense(qc->scsicmd);
+
+	return 0;
+}
+
+static void ata_eh_get_success_sense(struct ata_link *link)
+{
+	struct ata_eh_context *ehc = &link->eh_context;
+	struct ata_device *dev = link->device;
+	struct ata_port *ap = link->ap;
+	struct ata_queued_cmd *qc;
+	int tag, ret = 0;
+
+	if (!(ehc->i.dev_action[dev->devno] & ATA_EH_GET_SUCCESS_SENSE))
+		return;
+
+	/* if frozen, we can't do much */
+	if (ata_port_is_frozen(ap)) {
+		ata_dev_warn(dev,
+			"successful sense data available but port frozen\n");
+		goto out;
+	}
+
+	/*
+	 * If the link has sactive set, then we have outstanding NCQ commands
+	 * and have to read the Successful NCQ Commands log to get the sense
+	 * data. Otherwise, we are dealing with a non-NCQ command and use
+	 * request sense ext command to retrieve the sense data.
+	 */
+	if (link->sactive)
+		ret = ata_eh_read_sense_success_ncq_log(link);
+	else
+		ret = ata_eh_read_sense_success_non_ncq(link);
+	if (ret)
+		goto out;
+
+	ata_eh_done(link, dev, ATA_EH_GET_SUCCESS_SENSE);
+	return;
+
+out:
+	/*
+	 * If we failed to get sense data for a successful command that ought to
+	 * have sense data, we cannot simply return BLK_STS_OK to user space.
+	 * This is because we can't know if the sense data that we couldn't get
+	 * was actually "DATA CURRENTLY UNAVAILABLE". Reporting such a command
+	 * as success to user space would result in a silent data corruption.
+	 * Thus, add a bogus ABORTED_COMMAND sense data to such commands, such
+	 * that SCSI will report these commands as BLK_STS_IOERR to user space.
+	 */
+	ata_qc_for_each_raw(ap, qc, tag) {
+		if (!(qc->flags & ATA_QCFLAG_EH) ||
+		    !(qc->flags & ATA_QCFLAG_EH_SUCCESS_CMD) ||
+		    qc->err_mask ||
+		    ata_dev_phys_link(qc->dev) != link)
+			continue;
+
+		/* We managed to get sense for this success command, skip. */
+		if (qc->flags & ATA_QCFLAG_SENSE_VALID)
+			continue;
+
+		/* This success command did not have any sense data, skip. */
+		if (!(qc->result_tf.status & ATA_SENSE))
+			continue;
+
+		/* This success command had sense data, but we failed to get. */
+		ata_scsi_set_sense(dev, qc->scsicmd, true, ABORTED_COMMAND,
+				   0, 0);
+		qc->flags |= ATA_QCFLAG_SENSE_VALID;
+	}
+	ata_eh_done(link, dev, ATA_EH_GET_SUCCESS_SENSE);
+}
+
 /**
  *	ata_eh_link_autopsy - analyze error and determine recovery action
  *	@link: host link to perform autopsy on
@@ -1953,6 +2049,14 @@ static void ata_eh_link_autopsy(struct ata_link *link)
 	/* analyze NCQ failure */
 	ata_eh_analyze_ncq_error(link);
 
+	/*
+	 * Check if this was a successful command that simply needs sense data.
+	 * Since the sense data is not part of the completion, we need to fetch
+	 * it using an additional command. Since this can't be done from irq
+	 * context, the sense data for successful commands are fetched by EH.
+	 */
+	ata_eh_get_success_sense(link);
+
 	/* any real error trumps AC_ERR_OTHER */
 	if (ehc->i.err_mask & ~AC_ERR_OTHER)
 		ehc->i.err_mask &= ~AC_ERR_OTHER;
@@ -1962,6 +2066,7 @@ static void ata_eh_link_autopsy(struct ata_link *link)
 	ata_qc_for_each_raw(ap, qc, tag) {
 		if (!(qc->flags & ATA_QCFLAG_EH) ||
 		    qc->flags & ATA_QCFLAG_RETRY ||
+		    qc->flags & ATA_QCFLAG_EH_SUCCESS_CMD ||
 		    ata_dev_phys_link(qc->dev) != link)
 			continue;
 
@@ -3821,7 +3926,8 @@ void ata_eh_finish(struct ata_port *ap)
 			else
 				ata_eh_qc_complete(qc);
 		} else {
-			if (qc->flags & ATA_QCFLAG_SENSE_VALID) {
+			if (qc->flags & ATA_QCFLAG_SENSE_VALID ||
+			    qc->flags & ATA_QCFLAG_EH_SUCCESS_CMD) {
 				ata_eh_qc_complete(qc);
 			} else {
 				/* feed zero TF to sense generation */
diff --git a/drivers/ata/libata-sata.c b/drivers/ata/libata-sata.c
index b12f8e9e1f86..1c85e9eee619 100644
--- a/drivers/ata/libata-sata.c
+++ b/drivers/ata/libata-sata.c
@@ -11,7 +11,9 @@
 #include <linux/module.h>
 #include <scsi/scsi_cmnd.h>
 #include <scsi/scsi_device.h>
+#include <scsi/scsi_eh.h>
 #include <linux/libata.h>
+#include <asm/unaligned.h>
 
 #include "libata.h"
 #include "libata-transport.h"
@@ -1408,6 +1410,92 @@ static int ata_eh_read_log_10h(struct ata_device *dev,
 	return 0;
 }
 
+/**
+ *	ata_eh_read_sense_success_ncq_log - Read the sense data for successful
+ *					    NCQ commands log
+ *	@link: ATA link to get sense data for
+ *
+ *	Read the sense data for successful NCQ commands log page to obtain
+ *	sense data for all NCQ commands that completed successfully with
+ *	the sense data available bit set.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep).
+ *
+ *	RETURNS:
+ *	0 on success, -errno otherwise.
+ */
+int ata_eh_read_sense_success_ncq_log(struct ata_link *link)
+{
+	struct ata_device *dev = link->device;
+	struct ata_port *ap = dev->link->ap;
+	u8 *buf = ap->ncq_sense_buf;
+	struct ata_queued_cmd *qc;
+	unsigned int err_mask, tag;
+	u8 *sense, sk = 0, asc = 0, ascq = 0;
+	u64 sense_valid, val;
+	int ret = 0;
+
+	err_mask = ata_read_log_page(dev, ATA_LOG_SENSE_NCQ, 0, buf, 2);
+	if (err_mask) {
+		ata_dev_err(dev,
+			"Failed to read Sense Data for Successful NCQ Commands log\n");
+		return -EIO;
+	}
+
+	/* Check the log header */
+	val = get_unaligned_le64(&buf[0]);
+	if ((val & 0xffff) != 1 || ((val >> 16) & 0xff) != 0x0f) {
+		ata_dev_err(dev,
+			"Invalid Sense Data for Successful NCQ Commands log\n");
+		return -EIO;
+	}
+
+	sense_valid = (u64)buf[8] | ((u64)buf[9] << 8) |
+		((u64)buf[10] << 16) | ((u64)buf[11] << 24);
+
+	ata_qc_for_each_raw(ap, qc, tag) {
+		if (!(qc->flags & ATA_QCFLAG_EH) ||
+		    !(qc->flags & ATA_QCFLAG_EH_SUCCESS_CMD) ||
+		    qc->err_mask ||
+		    ata_dev_phys_link(qc->dev) != link)
+			continue;
+
+		/*
+		 * If the command does not have any sense data, clear ATA_SENSE.
+		 * Keep ATA_QCFLAG_EH_SUCCESS_CMD so that command is finished.
+		 */
+		if (!(sense_valid & (1ULL << tag))) {
+			qc->result_tf.status &= ~ATA_SENSE;
+			continue;
+		}
+
+		sense = &buf[32 + 24 * tag];
+		sk = sense[0];
+		asc = sense[1];
+		ascq = sense[2];
+
+		if (!ata_scsi_sense_is_valid(sk, asc, ascq)) {
+			ret = -EIO;
+			continue;
+		}
+
+		ata_scsi_set_sense(dev, qc->scsicmd, false, sk, asc, ascq);
+		qc->flags |= ATA_QCFLAG_SENSE_VALID;
+
+		/*
+		 * If we have sense data, call scsi_check_sense() in order to
+		 * set the correct SCSI ML byte (if any). No point in checking
+		 * the return value, since the command has already completed
+		 * successfully.
+		 */
+		scsi_check_sense(qc->scsicmd);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ata_eh_read_sense_success_ncq_log);
+
 /**
  *	ata_eh_analyze_ncq_error - analyze NCQ error
  *	@link: ATA link to analyze NCQ error for
@@ -1488,6 +1576,7 @@ void ata_eh_analyze_ncq_error(struct ata_link *link)
 
 	ata_qc_for_each_raw(ap, qc, tag) {
 		if (!(qc->flags & ATA_QCFLAG_EH) ||
+		    qc->flags & ATA_QCFLAG_EH_SUCCESS_CMD ||
 		    ata_dev_phys_link(qc->dev) != link)
 			continue;
 
diff --git a/include/linux/ata.h b/include/linux/ata.h
index a59b17d6ad11..2e2e22362096 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -326,6 +326,8 @@ enum {
 	ATA_LOG_CDL		= 0x18,
 	ATA_LOG_CDL_SIZE	= ATA_SECT_SIZE,
 	ATA_LOG_IDENTIFY_DEVICE	= 0x30,
+	ATA_LOG_SENSE_NCQ	= 0x0F,
+	ATA_LOG_SENSE_NCQ_SIZE	= ATA_SECT_SIZE * 2,
 	ATA_LOG_CONCURRENT_POSITIONING_RANGES = 0x47,
 
 	/* Identify device log pages: */
@@ -432,6 +434,7 @@ enum {
 	SATA_DEVSLP		= 0x09,	/* Device Sleep */
 
 	SETFEATURE_SENSE_DATA	= 0xC3, /* Sense Data Reporting feature */
+	SETFEATURE_SENSE_DATA_SUCC_NCQ = 0xC4, /* Sense Data for successful NCQ commands */
 
 	/* feature values for SET_MAX */
 	ATA_SET_MAX_ADDR	= 0x00,
diff --git a/include/linux/libata.h b/include/linux/libata.h
index ab8b62036c12..70ac635fe5d7 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -214,6 +214,7 @@ enum {
 	ATA_QCFLAG_EH		= (1 << 16), /* cmd aborted and owned by EH */
 	ATA_QCFLAG_SENSE_VALID	= (1 << 17), /* sense data valid */
 	ATA_QCFLAG_EH_SCHEDULED = (1 << 18), /* EH scheduled (obsolete) */
+	ATA_QCFLAG_EH_SUCCESS_CMD = (1 << 19), /* EH should fetch sense for this successful cmd */
 
 	/* host set flags */
 	ATA_HOST_SIMPLEX	= (1 << 0),	/* Host is simplex, one DMA channel per host only */
@@ -312,8 +313,10 @@ enum {
 	ATA_EH_RESET		= ATA_EH_SOFTRESET | ATA_EH_HARDRESET,
 	ATA_EH_ENABLE_LINK	= (1 << 3),
 	ATA_EH_PARK		= (1 << 5), /* unload heads and stop I/O */
+	ATA_EH_GET_SUCCESS_SENSE = (1 << 6), /* Get sense data for successful cmd */
 
-	ATA_EH_PERDEV_MASK	= ATA_EH_REVALIDATE | ATA_EH_PARK,
+	ATA_EH_PERDEV_MASK	= ATA_EH_REVALIDATE | ATA_EH_PARK |
+				  ATA_EH_GET_SUCCESS_SENSE,
 	ATA_EH_ALL_ACTIONS	= ATA_EH_REVALIDATE | ATA_EH_RESET |
 				  ATA_EH_ENABLE_LINK,
 
@@ -867,6 +870,7 @@ struct ata_port {
 	struct ata_acpi_gtm	__acpi_init_gtm; /* use ata_acpi_init_gtm() */
 #endif
 	/* owned by EH */
+	u8			*ncq_sense_buf;
 	u8			sector_buf[ATA_SECT_SIZE] ____cacheline_aligned;
 };
 
@@ -1185,6 +1189,7 @@ extern int sata_link_hardreset(struct ata_link *link,
 			bool *online, int (*check_ready)(struct ata_link *));
 extern int sata_link_resume(struct ata_link *link, const unsigned long *params,
 			    unsigned long deadline);
+extern int ata_eh_read_sense_success_ncq_log(struct ata_link *link);
 extern void ata_eh_analyze_ncq_error(struct ata_link *link);
 #else
 static inline const unsigned long *
@@ -1222,6 +1227,10 @@ static inline int sata_link_resume(struct ata_link *link,
 {
 	return -EOPNOTSUPP;
 }
+static inline int ata_eh_read_sense_success_ncq_log(struct ata_link *link)
+{
+	return -EOPNOTSUPP;
+}
 static inline void ata_eh_analyze_ncq_error(struct ata_link *link) { }
 #endif
 extern int sata_link_debounce(struct ata_link *link,
-- 
2.39.0

[PATCH v2 18/18] Documentation: sysfs-block-device: document command duration limits

[Niklas Cassel]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Document ABI/testing/sysfs-block-device the sysfs attributes present
under /sys/block/*/device/duration_limits for ATA and SCSI devices
supporting the command duration limits feature.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
---
 Documentation/ABI/testing/sysfs-block-device | 150 +++++++++++++++++++
 1 file changed, 150 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-block-device b/Documentation/ABI/testing/sysfs-block-device
index 7ac7b19b2f72..3a32c86942f5 100644
--- a/Documentation/ABI/testing/sysfs-block-device
+++ b/Documentation/ABI/testing/sysfs-block-device
@@ -95,3 +95,153 @@ Description:
 		This file does not exist if the HBA driver does not implement
 		support for the SATA NCQ priority feature, regardless of the
 		device support for this feature.
+
+
+What:		/sys/block/*/device/duration_limits/enable
+Date:		Dec, 2022
+KernelVersion:	v6.3
+Contact:	linux-scsi@vger.kernel.org
+Description:
+		(RW) For ATA and SCSI devices supporting the command duration
+		limits feature, write to the file to turn on or off the
+		feature. By default this feature is turned off. If the device
+		does not support the command duration limits feature, this
+		attribute does not exist (the directory
+		"/sys/block/\*/device/duration_limits" does not exist).
+		Writing "1" to this file enables the use of command duration
+		limits for read and write commands in the kernel and turns on
+		the feature on the device. Writing "0" disables the feature.
+
+
+What:		/sys/block/*/device/duration_limits/read/[1-7]/*
+Date:		Dec, 2022
+KernelVersion:	v6.3
+Contact:	linux-scsi@vger.kernel.org
+Description:
+		(RO) For ATA and SCSI devices supporting the command duration
+		limits feature, this shows the set of 7 command duration limits
+		descriptors for read commands currently set on the device. For
+		each of the 7 descritors, the following read-only attributes
+		are present:
+
+		  - duration_guideline: specifies the preferred length of time
+		    in microseconds for the completion of a command.
+
+		  - duration_guideline_policy: specifies the policy action
+		    taken if the duration_guideline attribute specifies a
+		    non-zero command duration guideline that the device is
+		    unable to achieve for a command.
+
+		    Possible values are:
+
+		      - 0x0: The device will complete the command at the
+			earliest possible time consistent with the specified
+			command duration guideline.
+
+		      - 0x1: If the specified command duration guideline has not
+			been achieved and the command duration guideline policy
+			field is not in the seventh command duration limits
+			descriptor, then the device continues processing that
+			command using the command duration limits descriptor
+			that has the next higher number.
+
+		      - 0x2: The device will continue processing the command as
+			with no command duration limits descriptor being used.
+
+		      - 0xD: The device will complete the command and an IO
+			failure will be reported to the user with the ETIME
+			error code.
+
+		      - 0xF: Same as 0xD.
+
+		  - max_active_time: specifies an upper limit in microseconds
+		    on the time that elapses from the time at which the device
+		    initiates actions to access, transfer, or act upon the
+		    specified data until the time the device returns status for
+		    the command.
+
+		  - max_active_time_policy: specifies the policy action taken
+		    if the time used to process a command exceeds a non-zero
+		    time specified by the max_active_time attribute.
+
+		    Possible values are:
+
+		      - 0x0: The device will complete the command at the
+			earliest possible time (i.e, do nothing based on the max
+			time limit not being met).
+
+		      - 0xD: The device will complete the command and an IO
+			failure will be reported to the user with the ETIME
+			error code.
+
+		      - 0xE: Same as 0xD.
+
+		      - 0xF: Same as 0xD.
+
+		  - max_inactive_time: specifies an upper limit in microseconds
+		    on the time that elapses from the time at which the device
+		    receives the command until the time at which the device
+		    initiates actions to access, transfer, or act upon the
+		    specified data.
+
+		  - max_inactive_time_policy: specifies the policy action taken
+		    if a non-zero max_inactive_time limit is not met.
+
+		    Possible values are:
+
+		      - 0x0: The device will complete the command at the
+			earliest possible time (i.e, do nothing based on the max
+			time limit not being met).
+
+		      - 0xD: The device will complete the command and an IO
+			failure will be reported to the user with the ETIME
+			error code.
+
+		      - 0xF: Same as 0xD.
+
+
+What:		/sys/block/*/device/duration_limits/read/page
+Date:		Dec, 2022
+KernelVersion:	v6.3
+Contact:	linux-scsi@vger.kernel.org
+Description:
+		(RO) For ATA and SCSI devices supporting the command duration
+		limits feature, this shows the name of the device VPD page
+		specifying the set of 7 command duration limits descriptors for
+		read commands. Possible values are "T2A" and "T2B".
+
+
+What:		/sys/block/*/device/duration_limits/write/[1-7]/*
+Date:		Dec, 2022
+KernelVersion:	v6.3
+Contact:	linux-scsi@vger.kernel.org
+Description:
+		(RO) For ATA and SCSI devices supporting the command duration
+		limits feature, this shows the set of 7 command duration limits
+		descriptors for write commands currently set on the device. For
+		each of the 7 descritors, the same set of read-only attributes
+		as for read commands is present.
+
+
+What:		/sys/block/*/device/duration_limits/write/page
+Date:		Dec, 2022
+KernelVersion:	v6.3
+Contact:	linux-scsi@vger.kernel.org
+Description:
+		(RO) For ATA and SCSI devices supporting the command duration
+		limits feature, this shows the name of the device VPD page
+		specifying the set of 7 command duration limits descriptors for
+		write commands. Possible values are "T2A" and "T2B".
+
+
+What:		/sys/block/*/device/duration_limits/perf_vs_duration_guideline
+Date:		Dec, 2022
+KernelVersion:	v6.3
+Contact:	linux-scsi@vger.kernel.org
+Description:
+		(RO) For ATA and SCSI devices supporting the command duration
+		limits feature, this specifies the maximum percentage increase
+		in average command completion times (reduction in IOPS) that
+		is allowed for the device to perform actions based on the
+		contents of the duration guideline field in every command
+		duration limit descriptor for both read and write commands.
-- 
2.39.0

Re: [PATCH v2 01/18] ata: libata: allow ata_scsi_set_sense() to not set CHECK_CONDITION

[Hannes Reinecke]

On 1/12/23 15:03, Niklas Cassel wrote:
> Current ata_scsi_set_sense() calls scsi_build_sense(), which,
> in addition to setting the sense data, unconditionally sets the
> scsicmd->result to SAM_STAT_CHECK_CONDITION.
> 
> For Command Duration Limits policy 0xD:
> The device shall complete the command without error (SAM_STAT_GOOD)
> with the additional sense code set to DATA CURRENTLY UNAVAILABLE.
> 
> It is perfectly fine to have sense data for a command that returned
> completion without error.
> 
> In order to support for CDL policy 0xD, we have to remove this
> assumption that having sense data means that the command failed
> (SAM_STAT_CHECK_CONDITION).
> 
> Add a new parameter to ata_scsi_set_sense() to allow us to set
> sense data without unconditionally setting SAM_STAT_CHECK_CONDITION.
> This new parameter will be used in a follow-up patch.
> 
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   drivers/ata/libata-eh.c   |  3 ++-
>   drivers/ata/libata-sata.c |  4 ++--
>   drivers/ata/libata-scsi.c | 38 ++++++++++++++++++++------------------
>   drivers/ata/libata.h      |  4 ++--
>   4 files changed, 26 insertions(+), 23 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew
Myers, Andrew McDonald, Martje Boudien Moerman

Re: [PATCH v2 02/18] ata: libata: allow ata_eh_request_sense() to not set CHECK_CONDITION

[Hannes Reinecke]

On 1/12/23 15:03, Niklas Cassel wrote:
> Current ata_eh_request_sense() calls ata_scsi_set_sense() with
> check_condition always set to true, which, in addition to setting the
> sense data, unconditionally sets the scsicmd->result to
> SAM_STAT_CHECK_CONDITION.
> 
> For Command Duration Limits policy 0xD:
> The device shall complete the command without error (SAM_STAT_GOOD)
> with the additional sense code set to DATA CURRENTLY UNAVAILABLE.
> 
> It is perfectly fine to have sense data for a command that returned
> completion without error.
> 
> In order to support for CDL policy 0xD, we have to remove this
> assumption that having sense data means that the command failed
> (SAM_STAT_CHECK_CONDITION).
> 
> Add a new parameter to ata_eh_request_sense() to allow us to request
> sense data without unconditionally setting SAM_STAT_CHECK_CONDITION.
> This new parameter will be used in a follow-up patch.
> 
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   drivers/ata/libata-eh.c | 10 ++++++----
>   1 file changed, 6 insertions(+), 4 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew
Myers, Andrew McDonald, Martje Boudien Moerman

Re: [PATCH v2 03/18] scsi: core: allow libata to complete successful commands via EH

[Hannes Reinecke]

On 1/12/23 15:03, Niklas Cassel wrote:
> In SCSI, we get the sense data as part of the completion, for ATA
> however, we need to fetch the sense data as an extra step. For an
> aborted ATA command the sense data is fetched via libata's
> ->eh_strategy_handler().
> 
> For Command Duration Limits policy 0xD:
> The device shall complete the command without error with the additional
> sense code set to DATA CURRENTLY UNAVAILABLE.
> 
> In order to handle this policy in libata, we intend to send a successful
> command via SCSI EH, and let libata's ->eh_strategy_handler() fetch the
> sense data for the good command. This is similar to how we handle an
> aborted ATA command, just that we need to read the Successful NCQ
> Commands log instead of the NCQ Command Error log.
> 
> When we get a SATA completion with successful commands, ATA_SENSE will
> be set, indicating that some commands in the completion have sense data.
> 
> The sense_valid bitmask in the Sense Data for Successful NCQ Commands
> log will inform exactly which commands that had sense data, which might
> be a subset of all the commands that was completed in the same
> completion. (Yet all will have ATA_SENSE set, since the status is per
> completion.)
> 
> The successful commands that have e.g. a "DATA CURRENTLY UNAVAILABLE"
> sense data will have a SCSI ML byte set, so scsi_eh_flush_done_q() will
> not set the scmd->result to DID_TIME_OUT for these commands. However,
> the successful commands that did not have sense data, must not get their
> result marked as DID_TIME_OUT by SCSI EH.
> 
> Add a new flag SCMD_EH_SUCCESS_CMD, which tells SCSI EH to not mark a
> command as DID_TIME_OUT, even if it has scmd->result == SAM_STAT_GOOD.
> 
> This will be used by libata in a follow-up patch.
> 
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   drivers/scsi/scsi_error.c | 3 ++-
>   include/scsi/scsi_cmnd.h  | 5 +++++
>   2 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> index 2aa2c2aee6e7..51aa5c1e31b5 100644
> --- a/drivers/scsi/scsi_error.c
> +++ b/drivers/scsi/scsi_error.c
> @@ -2165,7 +2165,8 @@ void scsi_eh_flush_done_q(struct list_head *done_q)
>   			 * scsi_eh_get_sense), scmd->result is already
>   			 * set, do not set DID_TIME_OUT.
>   			 */
> -			if (!scmd->result)
> +			if (!scmd->result &&
> +			    !(scmd->flags & SCMD_EH_SUCCESS_CMD))
>   				scmd->result |= (DID_TIME_OUT << 16);
>   			SCSI_LOG_ERROR_RECOVERY(3,
>   				scmd_printk(KERN_INFO, scmd,
Wouldn't it be better to use '!scmd->result && !scsi_sense_valid(scmd)' 
instead of a new flag?
After all, if we have a valid sense code we _have_ been able to 
communicate with the device. And as we did so it's questionable whether 
it should count as a command time out ...

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew
Myers, Andrew McDonald, Martje Boudien Moerman

Re: [PATCH v2 04/18] scsi: rename and move get_scsi_ml_byte()

[Hannes Reinecke]

On 1/12/23 15:03, Niklas Cassel wrote:
> SCSI has two different getters:
> - get_XXX_byte() (in scsi_cmnd.h) which takes a struct scsi_cmnd *, and
> - XXX_byte() (in scsi.h) which takes a scmd->result.
> The proper name for get_scsi_ml_byte() should thus be without the get_
> prefix, as it takes a scmd->result. Rename the function to rectify this.
> 
> Additionally, move get_scsi_ml_byte() to scsi_priv.h since both scsi_lib.c
> and scsi_error.c will need to use this helper in a follow-up patch.
> 
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   drivers/scsi/scsi_lib.c  | 7 +------
>   drivers/scsi/scsi_priv.h | 5 +++++
>   2 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 9ed1ebcb7443..6630a36b873e 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -579,11 +579,6 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
>   	return false;
>   }
>   
> -static inline u8 get_scsi_ml_byte(int result)
> -{
> -	return (result >> 8) & 0xff;
> -}
> -
>   /**
>    * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
>    * @result:	scsi error code
> @@ -596,7 +591,7 @@ static blk_status_t scsi_result_to_blk_status(int result)
>   	 * Check the scsi-ml byte first in case we converted a host or status
>   	 * byte.
>   	 */
> -	switch (get_scsi_ml_byte(result)) {
> +	switch (scsi_ml_byte(result)) {
>   	case SCSIML_STAT_OK:
>   		break;
>   	case SCSIML_STAT_RESV_CONFLICT:
> diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
> index 96284a0e13fe..74324fba4281 100644
> --- a/drivers/scsi/scsi_priv.h
> +++ b/drivers/scsi/scsi_priv.h
> @@ -29,6 +29,11 @@ enum scsi_ml_status {
>   	SCSIML_STAT_TGT_FAILURE		= 0x04,	/* Permanent target failure */
>   };
>   
> +static inline u8 scsi_ml_byte(int result)
> +{
> +	return (result >> 8) & 0xff;
> +}
> +
>   /*
>    * Scsi Error Handler Flags
>    */

Naming is hard :-)

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew
Myers, Andrew McDonald, Martje Boudien Moerman

Re: [PATCH v2 05/18] scsi: support retrieving sub-pages of mode pages

[Hannes Reinecke]

On 1/12/23 15:03, Niklas Cassel wrote:
> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> 
> Allow scsi_mode_sense() to retrieve sub-pages of mode pages by adding
> the subpage argument. Change all the current caller sites to specify
> the subpage 0.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   drivers/scsi/scsi_lib.c           | 4 +++-
>   drivers/scsi/scsi_transport_sas.c | 2 +-
>   drivers/scsi/sd.c                 | 9 ++++-----
>   drivers/scsi/sr.c                 | 2 +-
>   include/scsi/scsi_device.h        | 5 +++--
>   5 files changed, 12 insertions(+), 10 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Ivo Totev, Andrew
Myers, Andrew McDonald, Martje Boudien Moerman

Re: [PATCH v2 06/18] scsi: support service action in scsi_report_opcode()

[Hannes Reinecke]

On 1/12/23 15:03, Niklas Cassel wrote:
> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> 
> The REPORT_SUPPORTED_OPERATION_CODES command allows checking for support
> of commands that have the same opcode but different service actions,
> such as READ 32 and WRITE 32. However, the current implementation of
> scsi_report_opcode() only allows checking an operation code without a
> service action differentiation.
> 
> Add the "sa" argument to scsi_report_opcode() to allow passing a service
> action. If a non-zero service action is specified, the reporting
> options field value is set to 3 to have the service action field taken
> into account by the device. If no service action field is specified
> (zero), the reporting options field is set to 1 as before.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   drivers/scsi/scsi.c        | 28 +++++++++++++++++++---------
>   drivers/scsi/sd.c          | 10 +++++-----
>   include/scsi/scsi_device.h |  3 ++-
>   3 files changed, 26 insertions(+), 15 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer

Re: [PATCH v2 07/18] block: introduce duration-limits priority class

[Hannes Reinecke]

On 1/12/23 15:03, Niklas Cassel wrote:
> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> 
> Introduce the IOPRIO_CLASS_DL priority class to indicate that IOs should
> be executed using duration-limits targets. The duration target to apply
> to a command is indicated using the priority level. Up to 8 levels are
> supported, with level 0 indiating "no limit".
> 
> This priority class has effect only if the target device supports the
> command duration limits feature and this feature is enabled by the user.
> In BFQ and mq-deadline, all requests with this new priority class are
> handled using the highest priority class RT and priority level 0.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   block/bfq-iosched.c         | 10 ++++++++++
>   block/blk-ioprio.c          |  3 +++
>   block/ioprio.c              |  3 ++-
>   block/mq-deadline.c         |  1 +
>   include/linux/ioprio.h      |  2 +-
>   include/uapi/linux/ioprio.h |  7 +++++++
>   6 files changed, 24 insertions(+), 2 deletions(-)
> 
I wonder.

_Normally_ a command timeout is only in force once the command is being 
handed off to the driver. As such it doesn't apply for any scheduling 
being done before that; most notably the I/O scheduler is not affected 
by any command timeout.

And I was under the impression that CDL really only allows the drive to 
impose a command timeout on its own.
(Pray correct me if I'm mistaken)

Hence: does CDL really impinge on the I/O scheduler? Or shouldn't we 
treat CDL just like a 'normal' command timeout, only to be activated 
when normal command timeout is enabled?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer

Re: [PATCH v2 08/18] block: introduce BLK_STS_DURATION_LIMIT

[Hannes Reinecke]

On 1/12/23 15:03, Niklas Cassel wrote:
> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> 
> Introduce the new block IO status BLK_STS_DURATION_LIMIT for LLDDs to
> report command that failed due to a command duration limit being
> exceeded. This new status is mapped to the ETIME error code to allow
> users to differentiate "soft" duration limit failures from other more
> serious hardware related errors.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   block/blk-core.c          | 3 +++
>   include/linux/blk_types.h | 6 ++++++
>   2 files changed, 9 insertions(+)
> 
> diff --git a/block/blk-core.c b/block/blk-core.c
> index b5098355d8b2..67b0b24aa171 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -170,6 +170,9 @@ static const struct {
>   	[BLK_STS_ZONE_OPEN_RESOURCE]	= { -ETOOMANYREFS, "open zones exceeded" },
>   	[BLK_STS_ZONE_ACTIVE_RESOURCE]	= { -EOVERFLOW, "active zones exceeded" },
>   
> +	/* Command duration limit device-side timeout */
> +	[BLK_STS_DURATION_LIMIT]	= { -ETIME, "duration limit exceeded" },
> +
>   	/* everything else not covered above: */
>   	[BLK_STS_IOERR]		= { -EIO,	"I/O" },
>   };
> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index 99be590f952f..cde997590765 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -166,6 +166,12 @@ typedef u16 blk_short_t;
>    */
>   #define BLK_STS_OFFLINE		((__force blk_status_t)17)
>   
> +/*
> + * BLK_STS_DURATION_LIMIT is returned from the driver when the target device
> + * aborted the command because it exceeded one of its Command Duration Limits.
> + */
> +#define BLK_STS_DURATION_LIMIT	((__force blk_status_t)18)
> +
>   /**
>    * blk_path_error - returns true if error may be path related
>    * @error: status the request was completed with

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer

Re: [PATCH v2 09/18] ata: libata: detect support for command duration limits

[Hannes Reinecke]

On 1/12/23 15:03, Niklas Cassel wrote:
> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> 
> Use the supported capabilities identify device data log page to detect
> if a device supports the command duration limits feature. For devices
> supporting this feature, set the device flag ATA_DFLAG_CDL. To support
> scsi-ata translation, retrieve the command duration limits log page 18h
> and cache this page content using the cdl array added to the ata_device
> data structure.
> 
> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> Co-developed-by: Niklas Cassel <niklas.cassel@wdc.com>
> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> ---
>   drivers/ata/libata-core.c | 52 ++++++++++++++++++++++++++++++++++++++-
>   drivers/ata/libata-scsi.c | 17 ++++++-------
>   include/linux/ata.h       |  5 +++-
>   include/linux/libata.h    | 29 +++++++++++++---------
>   4 files changed, 80 insertions(+), 23 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer

Re: [PATCH v2 07/18] block: introduce duration-limits priority class

[Damien Le Moal]

On 1/13/23 20:55, Hannes Reinecke wrote:
> On 1/12/23 15:03, Niklas Cassel wrote:
>> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
>>
>> Introduce the IOPRIO_CLASS_DL priority class to indicate that IOs should
>> be executed using duration-limits targets. The duration target to apply
>> to a command is indicated using the priority level. Up to 8 levels are
>> supported, with level 0 indiating "no limit".
>>
>> This priority class has effect only if the target device supports the
>> command duration limits feature and this feature is enabled by the user.
>> In BFQ and mq-deadline, all requests with this new priority class are
>> handled using the highest priority class RT and priority level 0.
>>
>> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
>> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
>> ---
>>   block/bfq-iosched.c         | 10 ++++++++++
>>   block/blk-ioprio.c          |  3 +++
>>   block/ioprio.c              |  3 ++-
>>   block/mq-deadline.c         |  1 +
>>   include/linux/ioprio.h      |  2 +-
>>   include/uapi/linux/ioprio.h |  7 +++++++
>>   6 files changed, 24 insertions(+), 2 deletions(-)
>>
> I wonder.
> 
> _Normally_ a command timeout is only in force once the command is being 
> handed off to the driver. As such it doesn't apply for any scheduling 
> being done before that; most notably the I/O scheduler is not affected 
> by any command timeout.
> 
> And I was under the impression that CDL really only allows the drive to 
> impose a command timeout on its own.
> (Pray correct me if I'm mistaken)

The CDL descriptors to be used for read/write commands are defined by the
user and set on the drive (write log command). By default, the drive does
not have any CDL descriptor set, so no limit == regular behavior (no
timeout aborts). Also keep in mind that CDLs may be of the (1) "best
effort" flavor, or the (2) "abort" flavor. For (2), a command missing its
CDL limit will be aborted by the device (limit set by the user !). But for
(1), the drive will continue executing the command even if the CDL limit
is exceeded, so no timeout error.

> Hence: does CDL really impinge on the I/O scheduler? Or shouldn't we 
> treat CDL just like a 'normal' command timeout, only to be activated 
> when normal command timeout is enabled?

No impact on the IO scheduler, at least for now. But given that CDL is all
about controlling IO latency, we would miss that goal if we have an IO
scheduler that excessively delays a request with a short CDL set...

The main point of this patch is to have CDL commands treated similarly to
high priority commands to avoid such delays. This is also consistant with
the fact that CDL and ATA NCQ priority commands are mutually exclusive
features. They cannot be used together. So there we cannot have a mix of
CDL and NCQ prio commands together to the same drive.

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 03/18] scsi: core: allow libata to complete successful commands via EH

[Niklas Cassel]

On Fri, Jan 13, 2023 at 08:57:37AM +0100, Hannes Reinecke wrote:
> On 1/12/23 15:03, Niklas Cassel wrote:
> > In SCSI, we get the sense data as part of the completion, for ATA
> > however, we need to fetch the sense data as an extra step. For an
> > aborted ATA command the sense data is fetched via libata's
> > ->eh_strategy_handler().
> > 
> > For Command Duration Limits policy 0xD:
> > The device shall complete the command without error with the additional
> > sense code set to DATA CURRENTLY UNAVAILABLE.
> > 
> > In order to handle this policy in libata, we intend to send a successful
> > command via SCSI EH, and let libata's ->eh_strategy_handler() fetch the
> > sense data for the good command. This is similar to how we handle an
> > aborted ATA command, just that we need to read the Successful NCQ
> > Commands log instead of the NCQ Command Error log.
> > 
> > When we get a SATA completion with successful commands, ATA_SENSE will
> > be set, indicating that some commands in the completion have sense data.
> > 
> > The sense_valid bitmask in the Sense Data for Successful NCQ Commands
> > log will inform exactly which commands that had sense data, which might
> > be a subset of all the commands that was completed in the same
> > completion. (Yet all will have ATA_SENSE set, since the status is per
> > completion.)
> > 
> > The successful commands that have e.g. a "DATA CURRENTLY UNAVAILABLE"
> > sense data will have a SCSI ML byte set, so scsi_eh_flush_done_q() will
> > not set the scmd->result to DID_TIME_OUT for these commands. However,
> > the successful commands that did not have sense data, must not get their
> > result marked as DID_TIME_OUT by SCSI EH.
> > 
> > Add a new flag SCMD_EH_SUCCESS_CMD, which tells SCSI EH to not mark a
> > command as DID_TIME_OUT, even if it has scmd->result == SAM_STAT_GOOD.
> > 
> > This will be used by libata in a follow-up patch.
> > 
> > Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
> > ---
> >   drivers/scsi/scsi_error.c | 3 ++-
> >   include/scsi/scsi_cmnd.h  | 5 +++++
> >   2 files changed, 7 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> > index 2aa2c2aee6e7..51aa5c1e31b5 100644
> > --- a/drivers/scsi/scsi_error.c
> > +++ b/drivers/scsi/scsi_error.c
> > @@ -2165,7 +2165,8 @@ void scsi_eh_flush_done_q(struct list_head *done_q)
> >   			 * scsi_eh_get_sense), scmd->result is already
> >   			 * set, do not set DID_TIME_OUT.
> >   			 */
> > -			if (!scmd->result)
> > +			if (!scmd->result &&
> > +			    !(scmd->flags & SCMD_EH_SUCCESS_CMD))
> >   				scmd->result |= (DID_TIME_OUT << 16);
> >   			SCSI_LOG_ERROR_RECOVERY(3,
> >   				scmd_printk(KERN_INFO, scmd,
> Wouldn't it be better to use '!scmd->result && !scsi_sense_valid(scmd)'
> instead of a new flag?
> After all, if we have a valid sense code we _have_ been able to communicate
> with the device. And as we did so it's questionable whether it should count
> as a command time out ...

Hello Hannes,

Thanks a lot for helping out reviewing this series!

Unfortunately, your suggestion won't work.


Let me explain:

When you get a FIS, the ACT register will have a bit set for each
command that finished, however, all the commands will share a single
STATUS value (since there is just a shared STATUS field in the FIS).

So let's say that tags 0-3 got finished (i.e. bits 0-3 are set in the
ACT field) and the STATUS field has the "Sense Data Available" bit set.

This just tells us that at least one of tags 0-3 has sense data.


In order to know which of these tags that actually has sense data,
we need to read the "Sense Data for Successful NCQ Commands log",
which contains a sense_valid bitmask (which contains one bit for
each of the 32 tags).

So reading the "Sense Data for Successful NCQ Commands log" might
tell us that just tag 0-1 have sense data.

So, libata calls ata_qc_schedule_eh() on tags 0-3, wait until SCSI calls
libata .eh_strategy_handler(). libata .eh_strategy_handler() will read the
"Sense Data for Successful NCQ Commands log", which will see that there is
sense data for tags 0-1, and will add sense data for those commands, and
call scsi_check_sense() for tags 0-1.

ata_eh_finish() will finally be called, to determine what to do with the
commands that belonged to EH.

The code looks like this:
if (qc->flags & ATA_QCFLAG_SENSE_VALID ||
    qc->flags & ATA_QCFLAG_EH_SUCCESS_CMD) {
	ata_eh_qc_complete(qc);
}

So it will call complete for all 4 tags, regardless is they had sense data
or not.


scsi_eh_flush_done_q() will soon be called, and since ata_eh_qc_complete()
sets scmd->retries == scmd->allowed, none of the four commands will be retired.

if (!scmd->result &&
    !(scmd->flags & SCMD_EH_SUCCESS_CMD))
	scmd->result |= (DID_TIME_OUT << 16);

The 2 commands with sense data will not get DID_TIMEOUT,
because scmd->result has the SCSI ML byte set
(which is set by scsi_check_sense()).

The 2 commands without sense data will have scmd->result == 0,
so they will get DID_TIME_OUT set if we don't have the extra
!(scmd->flags & SCMD_EH_SUCCESS_CMD)) condition.


SCSI could add an additional check for:

if (!scmd->result && !scsi_sense_valid(scmd) &&
    !(scmd->flags & SCMD_EH_SUCCESS_CMD))
	scmd->result |= (DID_TIME_OUT << 16);

so that a command with does have sense data, but scsi_check_sense()
did not set any SCSI ML byte, does not get DID_TIME_OUT set.

However, for CDL policy 0xD, which this patch cares about,
we would still need the "&& !(scmd->flags & SCMD_EH_SUCCESS_CMD))",
so at least from a CDL perspective, I don't see how any benefit of
also adding a check for "&& !scsi_sense_valid(scmd)".


Kind regards,
Niklas

Re: [PATCH v2 01/18] ata: libata: allow ata_scsi_set_sense() to not set CHECK_CONDITION

[Christoph Hellwig]

>  void ata_scsi_set_sense(struct ata_device *dev, struct scsi_cmnd *cmd,
> -			u8 sk, u8 asc, u8 ascq)
> +			bool check_condition, u8 sk, u8 asc, u8 ascq)
>  {
>  	bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
>  
>  	if (!cmd)
>  		return;
>  
> -	scsi_build_sense(cmd, d_sense, sk, asc, ascq);
> +	scsi_build_sense_buffer(d_sense, cmd->sense_buffer, sk, asc, ascq);
> +	if (check_condition)
> +		set_status_byte(cmd, SAM_STAT_CHECK_CONDITION);
>  }

Adding a bool parameter do do something conditional at the end
of a function is always a bad idea.  Just split out a
__ata_scsi_set_sense helper that doesn't set the flag.

Re: [PATCH v2 02/18] ata: libata: allow ata_eh_request_sense() to not set CHECK_CONDITION

[Christoph Hellwig]

Similar comment here - just move setting the SAM_STAT_CHECK_CONDITION
out of this function and into the caller.  It'll need a bool return for
that, though.

Re: [PATCH v2 04/18] scsi: rename and move get_scsi_ml_byte()

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH v2 05/18] scsi: support retrieving sub-pages of mode pages

[Christoph Hellwig]

>  extern int scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
> -			   unsigned char *buffer, int len, int timeout,
> -			   int retries, struct scsi_mode_data *data,
> +			   int subpage, unsigned char *buffer, int len,
> +			   int timeout, int retries,
> +			   struct scsi_mode_data *data,

Please drop the extern while you're at it.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH v2 06/18] scsi: support service action in scsi_report_opcode()

[Christoph Hellwig]

Same comment about the extern, otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH v2 01/18] ata: libata: allow ata_scsi_set_sense() to not set CHECK_CONDITION

[Damien Le Moal]

On 1/17/23 15:06, Christoph Hellwig wrote:
>>  void ata_scsi_set_sense(struct ata_device *dev, struct scsi_cmnd *cmd,
>> -			u8 sk, u8 asc, u8 ascq)
>> +			bool check_condition, u8 sk, u8 asc, u8 ascq)
>>  {
>>  	bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
>>  
>>  	if (!cmd)
>>  		return;
>>  
>> -	scsi_build_sense(cmd, d_sense, sk, asc, ascq);
>> +	scsi_build_sense_buffer(d_sense, cmd->sense_buffer, sk, asc, ascq);
>> +	if (check_condition)
>> +		set_status_byte(cmd, SAM_STAT_CHECK_CONDITION);
>>  }
> 
> Adding a bool parameter do do something conditional at the end
> of a function is always a bad idea.  Just split out a
> __ata_scsi_set_sense helper that doesn't set the flag.

What about passing the SAM_STAT_XXX status to set as an argument ?
Most current call site will be modified to pass SAM_STAT_CHECK_CONDITION,
and we could add a wrapper ata_scsi_set_check_condition_sense() to
simplify this most common case.

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 01/18] ata: libata: allow ata_scsi_set_sense() to not set CHECK_CONDITION

[Christoph Hellwig]

On Tue, Jan 17, 2023 at 04:10:15PM +0900, Damien Le Moal wrote:
> >> +			bool check_condition, u8 sk, u8 asc, u8 ascq)
> >>  {
> >>  	bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
> >>  
> >>  	if (!cmd)
> >>  		return;
> >>  
> >> -	scsi_build_sense(cmd, d_sense, sk, asc, ascq);
> >> +	scsi_build_sense_buffer(d_sense, cmd->sense_buffer, sk, asc, ascq);
> >> +	if (check_condition)
> >> +		set_status_byte(cmd, SAM_STAT_CHECK_CONDITION);
> >>  }
> > 
> > Adding a bool parameter do do something conditional at the end
> > of a function is always a bad idea.  Just split out a
> > __ata_scsi_set_sense helper that doesn't set the flag.
> 
> What about passing the SAM_STAT_XXX status to set as an argument ?
> Most current call site will be modified to pass SAM_STAT_CHECK_CONDITION,
> and we could add a wrapper ata_scsi_set_check_condition_sense() to
> simplify this most common case.

What's the point of that?

Re: [PATCH v2 01/18] ata: libata: allow ata_scsi_set_sense() to not set CHECK_CONDITION

[Damien Le Moal]

On 1/17/23 16:12, Christoph Hellwig wrote:
> On Tue, Jan 17, 2023 at 04:10:15PM +0900, Damien Le Moal wrote:
>>>> +			bool check_condition, u8 sk, u8 asc, u8 ascq)
>>>>  {
>>>>  	bool d_sense = (dev->flags & ATA_DFLAG_D_SENSE);
>>>>  
>>>>  	if (!cmd)
>>>>  		return;
>>>>  
>>>> -	scsi_build_sense(cmd, d_sense, sk, asc, ascq);
>>>> +	scsi_build_sense_buffer(d_sense, cmd->sense_buffer, sk, asc, ascq);
>>>> +	if (check_condition)
>>>> +		set_status_byte(cmd, SAM_STAT_CHECK_CONDITION);
>>>>  }
>>>
>>> Adding a bool parameter do do something conditional at the end
>>> of a function is always a bad idea.  Just split out a
>>> __ata_scsi_set_sense helper that doesn't set the flag.
>>
>> What about passing the SAM_STAT_XXX status to set as an argument ?
>> Most current call site will be modified to pass SAM_STAT_CHECK_CONDITION,
>> and we could add a wrapper ata_scsi_set_check_condition_sense() to
>> simplify this most common case.
> 
> What's the point of that?

Trying to get to a pretty solution keeping a single line for setting sense
+ status. But sure, splitting out the status setting works too.

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 01/18] ata: libata: allow ata_scsi_set_sense() to not set CHECK_CONDITION

[Christoph Hellwig]

On Tue, Jan 17, 2023 at 04:15:01PM +0900, Damien Le Moal wrote:
> Trying to get to a pretty solution keeping a single line for setting sense
> + status. But sure, splitting out the status setting works too.

I suggested just adding a wrapper above.  And while I tried to white
board code it here in the mail I think we can do even better than
that, and just drop this change and just open code the call to
scsi_build_sense_buffer for the CDL use case.

While we're at it:  That !cmd check in ata_scsi_set_sense looks
really odd, can someone clean that up and just remove the calls
where there is no command?

Re: [PATCH v2 03/18] scsi: core: allow libata to complete successful commands via EH

[Christoph Hellwig]

I'd rename the flag to something like SCMD_FORCE_EH_SUCCESS,
but otherwise this looks good.

Re: [PATCH v2 07/18] block: introduce duration-limits priority class

[Christoph Hellwig]

On Thu, Jan 12, 2023 at 03:03:56PM +0100, Niklas Cassel wrote:
> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
> 
> Introduce the IOPRIO_CLASS_DL priority class to indicate that IOs should
> be executed using duration-limits targets. The duration target to apply
> to a command is indicated using the priority level. Up to 8 levels are
> supported, with level 0 indiating "no limit".
> 
> This priority class has effect only if the target device supports the
> command duration limits feature and this feature is enabled by the user.
> In BFQ and mq-deadline, all requests with this new priority class are
> handled using the highest priority class RT and priority level 0.

Hmm, does it make sense to force a high priority?  Can't applications
use CDL to also fore a lower priority?

Re: [PATCH v2 08/18] block: introduce BLK_STS_DURATION_LIMIT

[Christoph Hellwig]

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH v2 14/18] scsi: sd: detect support for command duration limits

[Christoph Hellwig]

Is sysfs really the right interface here?  I would have expected an
ioctl (and for kernel use method) on the block device to more
useful.  Especially all the dynamic sysfs manipulation from a driver
is a little scary to me.

Re: [PATCH v2 14/18] scsi: sd: detect support for command duration limits

[Damien Le Moal]

On 1/17/23 16:37, Christoph Hellwig wrote:
> Is sysfs really the right interface here?  I would have expected an
> ioctl (and for kernel use method) on the block device to more
> useful.  Especially all the dynamic sysfs manipulation from a driver
> is a little scary to me.

I found it convenient to have everything in sysfs as everything is visible
from the shell without needing any extra tooling. And I did that because I
thought ioctls should not be added... We could add one though, but then I
do not see much value since cdl-tools (cdladm utility) and sg3utils/sdparm
can give that information already.

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 07/18] block: introduce duration-limits priority class

[Damien Le Moal]

On 1/17/23 16:25, Christoph Hellwig wrote:
> On Thu, Jan 12, 2023 at 03:03:56PM +0100, Niklas Cassel wrote:
>> From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
>>
>> Introduce the IOPRIO_CLASS_DL priority class to indicate that IOs should
>> be executed using duration-limits targets. The duration target to apply
>> to a command is indicated using the priority level. Up to 8 levels are
>> supported, with level 0 indiating "no limit".
>>
>> This priority class has effect only if the target device supports the
>> command duration limits feature and this feature is enabled by the user.
>> In BFQ and mq-deadline, all requests with this new priority class are
>> handled using the highest priority class RT and priority level 0.
> 
> Hmm, does it make sense to force a high priority?  Can't applications
> use CDL to also fore a lower priority?

They can, by using a large limit for "low priority" IOs. But then, these
would still have a limit while any IO issued simultaneously without a CDL
index specified would have no limit at all. So strictly speaking, the no
limit IOs should be considered as even lower priority that CDL IOs with
large limits.

The other aspect here is that on ATA drives, CDL and NCQ priority cannot
be used together. A mix of CDL and high priority commands cannot be sent
to a device. Combining this with the above thinking, it made sense to me
to have the CDL priority class handled the same as the RT class (as that
is the one that maps to ATA NCQ high prio commands).

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 07/18] block: introduce duration-limits priority class

[Christoph Hellwig]

On Tue, Jan 17, 2023 at 05:06:52PM +0900, Damien Le Moal wrote:
> They can, by using a large limit for "low priority" IOs. But then, these
> would still have a limit while any IO issued simultaneously without a CDL
> index specified would have no limit at all. So strictly speaking, the no
> limit IOs should be considered as even lower priority that CDL IOs with
> large limits.
> 
> The other aspect here is that on ATA drives, CDL and NCQ priority cannot
> be used together. A mix of CDL and high priority commands cannot be sent
> to a device. Combining this with the above thinking, it made sense to me
> to have the CDL priority class handled the same as the RT class (as that
> is the one that maps to ATA NCQ high prio commands).

Ok.  Maybe document this a bit better in the commit log.

Re: [PATCH v2 07/18] block: introduce duration-limits priority class

[Damien Le Moal]

On 1/17/23 17:13, Christoph Hellwig wrote:
> On Tue, Jan 17, 2023 at 05:06:52PM +0900, Damien Le Moal wrote:
>> They can, by using a large limit for "low priority" IOs. But then, these
>> would still have a limit while any IO issued simultaneously without a CDL
>> index specified would have no limit at all. So strictly speaking, the no
>> limit IOs should be considered as even lower priority that CDL IOs with
>> large limits.
>>
>> The other aspect here is that on ATA drives, CDL and NCQ priority cannot
>> be used together. A mix of CDL and high priority commands cannot be sent
>> to a device. Combining this with the above thinking, it made sense to me
>> to have the CDL priority class handled the same as the RT class (as that
>> is the one that maps to ATA NCQ high prio commands).
> 
> Ok.  Maybe document this a bit better in the commit log.

OK. Will do.

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH v2 03/18] scsi: core: allow libata to complete successful commands via EH

[Hannes Reinecke]

On 1/16/23 13:43, Niklas Cassel wrote:
> On Fri, Jan 13, 2023 at 08:57:37AM +0100, Hannes Reinecke wrote:
>> On 1/12/23 15:03, Niklas Cassel wrote:
>>> In SCSI, we get the sense data as part of the completion, for ATA
>>> however, we need to fetch the sense data as an extra step. For an
>>> aborted ATA command the sense data is fetched via libata's
>>> ->eh_strategy_handler().
>>>
>>> For Command Duration Limits policy 0xD:
>>> The device shall complete the command without error with the additional
>>> sense code set to DATA CURRENTLY UNAVAILABLE.
>>>
>>> In order to handle this policy in libata, we intend to send a successful
>>> command via SCSI EH, and let libata's ->eh_strategy_handler() fetch the
>>> sense data for the good command. This is similar to how we handle an
>>> aborted ATA command, just that we need to read the Successful NCQ
>>> Commands log instead of the NCQ Command Error log.
>>>
>>> When we get a SATA completion with successful commands, ATA_SENSE will
>>> be set, indicating that some commands in the completion have sense data.
>>>
>>> The sense_valid bitmask in the Sense Data for Successful NCQ Commands
>>> log will inform exactly which commands that had sense data, which might
>>> be a subset of all the commands that was completed in the same
>>> completion. (Yet all will have ATA_SENSE set, since the status is per
>>> completion.)
>>>
>>> The successful commands that have e.g. a "DATA CURRENTLY UNAVAILABLE"
>>> sense data will have a SCSI ML byte set, so scsi_eh_flush_done_q() will
>>> not set the scmd->result to DID_TIME_OUT for these commands. However,
>>> the successful commands that did not have sense data, must not get their
>>> result marked as DID_TIME_OUT by SCSI EH.
>>>
>>> Add a new flag SCMD_EH_SUCCESS_CMD, which tells SCSI EH to not mark a
>>> command as DID_TIME_OUT, even if it has scmd->result == SAM_STAT_GOOD.
>>>
>>> This will be used by libata in a follow-up patch.
>>>
>>> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
>>> ---
>>>    drivers/scsi/scsi_error.c | 3 ++-
>>>    include/scsi/scsi_cmnd.h  | 5 +++++
>>>    2 files changed, 7 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
>>> index 2aa2c2aee6e7..51aa5c1e31b5 100644
>>> --- a/drivers/scsi/scsi_error.c
>>> +++ b/drivers/scsi/scsi_error.c
>>> @@ -2165,7 +2165,8 @@ void scsi_eh_flush_done_q(struct list_head *done_q)
>>>    			 * scsi_eh_get_sense), scmd->result is already
>>>    			 * set, do not set DID_TIME_OUT.
>>>    			 */
>>> -			if (!scmd->result)
>>> +			if (!scmd->result &&
>>> +			    !(scmd->flags & SCMD_EH_SUCCESS_CMD))
>>>    				scmd->result |= (DID_TIME_OUT << 16);
>>>    			SCSI_LOG_ERROR_RECOVERY(3,
>>>    				scmd_printk(KERN_INFO, scmd,
>> Wouldn't it be better to use '!scmd->result && !scsi_sense_valid(scmd)'
>> instead of a new flag?
>> After all, if we have a valid sense code we _have_ been able to communicate
>> with the device. And as we did so it's questionable whether it should count
>> as a command time out ...
> 
> Hello Hannes,
> 
> Thanks a lot for helping out reviewing this series!
> 
> Unfortunately, your suggestion won't work.
> 
> 
> Let me explain:
> 
> When you get a FIS, the ACT register will have a bit set for each
> command that finished, however, all the commands will share a single
> STATUS value (since there is just a shared STATUS field in the FIS).
> 
> So let's say that tags 0-3 got finished (i.e. bits 0-3 are set in the
> ACT field) and the STATUS field has the "Sense Data Available" bit set.
> 
> This just tells us that at least one of tags 0-3 has sense data.
> 
> 
> In order to know which of these tags that actually has sense data,
> we need to read the "Sense Data for Successful NCQ Commands log",
> which contains a sense_valid bitmask (which contains one bit for
> each of the 32 tags).
> 
> So reading the "Sense Data for Successful NCQ Commands log" might
> tell us that just tag 0-1 have sense data.
> 
> So, libata calls ata_qc_schedule_eh() on tags 0-3, wait until SCSI calls
> libata .eh_strategy_handler(). libata .eh_strategy_handler() will read the
> "Sense Data for Successful NCQ Commands log", which will see that there is
> sense data for tags 0-1, and will add sense data for those commands, and
> call scsi_check_sense() for tags 0-1.
> 
> ata_eh_finish() will finally be called, to determine what to do with the
> commands that belonged to EH.
> 
> The code looks like this:
> if (qc->flags & ATA_QCFLAG_SENSE_VALID ||
>      qc->flags & ATA_QCFLAG_EH_SUCCESS_CMD) {
> 	ata_eh_qc_complete(qc);
> }
> 
> So it will call complete for all 4 tags, regardless is they had sense data
> or not.
> 
> 
> scsi_eh_flush_done_q() will soon be called, and since ata_eh_qc_complete()
> sets scmd->retries == scmd->allowed, none of the four commands will be retired.
> 
> if (!scmd->result &&
>      !(scmd->flags & SCMD_EH_SUCCESS_CMD))
> 	scmd->result |= (DID_TIME_OUT << 16);
> 
> The 2 commands with sense data will not get DID_TIMEOUT,
> because scmd->result has the SCSI ML byte set
> (which is set by scsi_check_sense()).
> 
> The 2 commands without sense data will have scmd->result == 0,
> so they will get DID_TIME_OUT set if we don't have the extra
> !(scmd->flags & SCMD_EH_SUCCESS_CMD)) condition.
> 
> 
> SCSI could add an additional check for:
> 
> if (!scmd->result && !scsi_sense_valid(scmd) &&
>      !(scmd->flags & SCMD_EH_SUCCESS_CMD))
> 	scmd->result |= (DID_TIME_OUT << 16);
> 
> so that a command with does have sense data, but scsi_check_sense()
> did not set any SCSI ML byte, does not get DID_TIME_OUT set.
> 
> However, for CDL policy 0xD, which this patch cares about,
> we would still need the "&& !(scmd->flags & SCMD_EH_SUCCESS_CMD))",
> so at least from a CDL perspective, I don't see how any benefit of
> also adding a check for "&& !scsi_sense_valid(scmd)".
> 

Right, I see.
Thanks for the explanation.

You can add:

Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer