scsi: ufs: core: Retry START_STOP on UNIT_ATTENTION

Commit 57d104c153d3 ("ufs: add UFS power management support") made the UFS
driver submit a REQUEST SENSE command before submitting a power management
command to a WLUN to clear the POWER ON unit attention. Instead of
submitting a REQUEST SENSE command before submitting a power management
command, retry the power management command until it succeeds.

This is the preparation to get rid of all UNIT ATTENTION code which should
be handled by users.

Link: https://lore.kernel.org/r/20211001182015.1347587-2-jaegeuk@kernel.org
Cc: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 7126b7a..db5f375 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -8675,7 +8675,7 @@ static int ufshcd_set_dev_pwr_mode(struct ufs_hba *hba,
        struct scsi_sense_hdr sshdr;
        struct scsi_device *sdp;
        unsigned long flags;
-       int ret;
+       int ret, retries;
 
        spin_lock_irqsave(hba->host->host_lock, flags);
        sdp = hba->sdev_ufs_device;
@@ -8710,8 +8710,14 @@ static int ufshcd_set_dev_pwr_mode(struct ufs_hba *hba,
         * callbacks hence set the RQF_PM flag so that it doesn't resume the
         * already suspended childs.
         */
-       ret = scsi_execute(sdp, cmd, DMA_NONE, NULL, 0, NULL, &sshdr,
-                       START_STOP_TIMEOUT, 0, 0, RQF_PM, NULL);
+       for (retries = 3; retries > 0; --retries) {
+               ret = scsi_execute(sdp, cmd, DMA_NONE, NULL, 0, NULL, &sshdr,
+                               START_STOP_TIMEOUT, 0, 0, RQF_PM, NULL);
+               if (!scsi_status_is_check_condition(ret) ||
+                               !scsi_sense_valid(&sshdr) ||
+                               sshdr.sense_key != UNIT_ATTENTION)
+                       break;
+       }
        if (ret) {
                sdev_printk(KERN_WARNING, sdp,
                            "START_STOP failed for power mode: %d, result %x\n",