Patch "scsi: mpt3sas: Proper handling of set/clear of "ATA command pending" flag." has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

scsi: mpt3sas: Proper handling of set/clear of "ATA command pending" flag.

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
scsi-mpt3sas-proper-handling-of-set-clear-of-ata-command-pending-flag.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Chaitra P B <[email protected]>
Date: Wed, 27 Dec 2017 23:09:11 -0800
Subject: scsi: mpt3sas: Proper handling of set/clear of "ATA command pending" flag.

From: Chaitra P B <[email protected]>

[ Upstream commit f49d4aed1315a7b766d855f1367142e682b0cc87 ]

1. In IO path, setting of "ATA command pending" flag early before device removal, invalid device handle etc., checks causes any new commands to be always returned with SAM_STAT_BUSY and when the driver removes the drive the SML issues SYNC Cache command and that command is always returned with SAM_STAT_BUSY and thus making SYNC Cache command to requeued.

2. If the driver gets an ATA PT command for a SATA drive then the driver set "ATA command pending" flag in device specific data structure not to allow any further commands until the ATA PT command is completed. However, after setting the flag if the driver decides to return the command back to upper layers without actually issuing to the firmware (i.e., returns from qcmd failure return paths) then the corresponding flag is not cleared and this prevents the driver from sending any new commands to the drive.

This patch fixes above two issues by setting of "ATA command pending" flag after checking for whether device deleted, invalid device handle, device busy with task management. And by setting "ATA command pending" flag to false in all of the qcmd failure return paths after setting the flag.

---
 drivers/scsi/mpt3sas/mpt3sas_scsih.c |   28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

@@ -4106,19 +4106,6 @@ scsih_qcmd(struct Scsi_Host *shost, stru
 		return 0;
 	}
 
-	/*
-	 * Bug work around for firmware SATL handling.  The loop
-	 * is based on atomic operations and ensures consistency
-	 * since we're lockless at this point
-	 */
-	do {
-		if (test_bit(0, &sas_device_priv_data->ata_command_pending)) {
-			scmd->result = SAM_STAT_BUSY;
-			scmd->scsi_done(scmd);
-			return 0;
-		}
-	} while (_scsih_set_satl_pending(scmd, true));
-
 	sas_target_priv_data = sas_device_priv_data->sas_target;
 
 	/* invalid device handle */

@@ -4144,6 +4131,19 @@ scsih_qcmd(struct Scsi_Host *shost, stru
 	    sas_device_priv_data->block)
 		return SCSI_MLQUEUE_DEVICE_BUSY;
 
+	/*
+	 * Bug work around for firmware SATL handling.  The loop
+	 * is based on atomic operations and ensures consistency
+	 * since we're lockless at this point
+	 */
+	do {
+		if (test_bit(0, &sas_device_priv_data->ata_command_pending)) {
+			scmd->result = SAM_STAT_BUSY;
+			scmd->scsi_done(scmd);
+			return 0;
+		}
+	} while (_scsih_set_satl_pending(scmd, true));
+
 	if (scmd->sc_data_direction == DMA_FROM_DEVICE)
 		mpi_control = MPI2_SCSIIO_CONTROL_READ;
 	else if (scmd->sc_data_direction == DMA_TO_DEVICE)

@@ -4170,6 +4170,7 @@ scsih_qcmd(struct Scsi_Host *shost, stru
 	if (!smid) {
 		pr_err(MPT3SAS_FMT "%s: failed obtaining a smid\n",
 		    ioc->name, __func__);
+		_scsih_set_satl_pending(scmd, false);
 		goto out;
 	}
 	mpi_request = mpt3sas_base_get_msg_frame(ioc, smid);

@@ -4200,6 +4201,7 @@ scsih_qcmd(struct Scsi_Host *shost, stru
 	if (mpi_request->DataLength) {
 		if (ioc->build_sg_scmd(ioc, scmd, smid)) {
 			mpt3sas_base_free_smid(ioc, smid);
+			_scsih_set_satl_pending(scmd, false);
 			goto out;
 		}
 	} else

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/scsi-mpt3sas-proper-handling-of-set-clear-of-ata-command-pending-flag.patch