Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
 "ufs driver plus two core fixes.

  One core fix makes the unit attention counters atomic (just in case
  multiple commands detect them) and the other is fixing a merge window
  regression caused by changes in the block tree"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: core: Fix the unit attention counter implementation
  scsi: ufs: core: Declare tx_lanes witout initialization
  scsi: ufs: core: Initialize value of an attribute returned by uic cmd
  scsi: ufs: core: Fix error handler host_sem issue
  scsi: core: Fix a regression triggered by scsi_host_busy()

Author: torvalds

drivers/scsi/hosts.c

@@ -611,8 +611,9 @@ int scsi_host_busy(struct Scsi_Host *shost)
 {
 	int cnt = 0;
 
-	blk_mq_tagset_busy_iter(&shost->tag_set,
-				scsi_host_check_in_flight, &cnt);
+	if (shost->tag_set.ops)
+		blk_mq_tagset_busy_iter(&shost->tag_set,
+					scsi_host_check_in_flight, &cnt);
 	return cnt;
 }
 EXPORT_SYMBOL(scsi_host_busy);

drivers/scsi/scsi_error.c

@@ -554,9 +554,9 @@ enum scsi_disposition scsi_check_sense(struct scsi_cmnd *scmd)
 		 * happened, even if someone else gets the sense data.
 		 */
 		if (sshdr.asc == 0x28)
-			scmd->device->ua_new_media_ctr++;
+			atomic_inc(&sdev->ua_new_media_ctr);
 		else if (sshdr.asc == 0x29)
-			scmd->device->ua_por_ctr++;
+			atomic_inc(&sdev->ua_por_ctr);
 	}
 
 	if (scsi_sense_is_deferred(&sshdr))

drivers/ufs/core/ufshcd.c

@@ -4282,8 +4282,8 @@ int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
 			get, UIC_GET_ATTR_ID(attr_sel),
 			UFS_UIC_COMMAND_RETRIES - retries);
 
-	if (mib_val && !ret)
-		*mib_val = uic_cmd.argument3;
+	if (mib_val)
+		*mib_val = ret == 0 ? uic_cmd.argument3 : 0;
 
 	if (peer && (hba->quirks & UFSHCD_QUIRK_DME_PEER_ACCESS_AUTO_MODE)
 	    && pwr_mode_change)
@@ -4999,7 +4999,7 @@ EXPORT_SYMBOL_GPL(ufshcd_hba_enable);
 
 static int ufshcd_disable_tx_lcc(struct ufs_hba *hba, bool peer)
 {
-	int tx_lanes = 0, i, err = 0;
+	int tx_lanes, i, err = 0;
 
 	if (!peer)
 		ufshcd_dme_get(hba, UIC_ARG_MIB(PA_CONNECTEDTXDATALANES),
@@ -6673,6 +6673,20 @@ static void ufshcd_err_handler(struct work_struct *work)
 		 hba->saved_uic_err, hba->force_reset,
 		 ufshcd_is_link_broken(hba) ? "; link is broken" : "");
 
+	/*
+	 * Use ufshcd_rpm_get_noresume() here to safely perform link recovery
+	 * even if an error occurs during runtime suspend or runtime resume.
+	 * This avoids potential deadlocks that could happen if we tried to
+	 * resume the device while a PM operation is already in progress.
+	 */
+	ufshcd_rpm_get_noresume(hba);
+	if (hba->pm_op_in_progress) {
+		ufshcd_link_recovery(hba);
+		ufshcd_rpm_put(hba);
+		return;
+	}
+	ufshcd_rpm_put(hba);
+
 	down(&hba->host_sem);
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	if (ufshcd_err_handling_should_stop(hba)) {
@@ -6684,14 +6698,6 @@ static void ufshcd_err_handler(struct work_struct *work)
 	}
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 
-	ufshcd_rpm_get_noresume(hba);
-	if (hba->pm_op_in_progress) {
-		ufshcd_link_recovery(hba);
-		ufshcd_rpm_put(hba);
-		return;
-	}
-	ufshcd_rpm_put(hba);
-
 	ufshcd_err_handling_prepare(hba);
 
 	spin_lock_irqsave(hba->host->host_lock, flags);

include/scsi/scsi_device.h

@@ -252,8 +252,8 @@ struct scsi_device {
 	unsigned int queue_stopped;	/* request queue is quiesced */
 	bool offline_already;		/* Device offline message logged */
 
-	unsigned int ua_new_media_ctr;	/* Counter for New Media UNIT ATTENTIONs */
-	unsigned int ua_por_ctr;	/* Counter for Power On / Reset UAs */
+	atomic_t ua_new_media_ctr;	/* Counter for New Media UNIT ATTENTIONs */
+	atomic_t ua_por_ctr;		/* Counter for Power On / Reset UAs */
 
 	atomic_t disk_events_disable_depth; /* disable depth for disk events */
 
@@ -693,10 +693,8 @@ static inline int scsi_device_busy(struct scsi_device *sdev)
 }
 
 /* Macros to access the UNIT ATTENTION counters */
-#define scsi_get_ua_new_media_ctr(sdev) \
-	((const unsigned int)(sdev->ua_new_media_ctr))
-#define scsi_get_ua_por_ctr(sdev) \
-	((const unsigned int)(sdev->ua_por_ctr))
+#define scsi_get_ua_new_media_ctr(sdev)	atomic_read(&sdev->ua_new_media_ctr)
+#define scsi_get_ua_por_ctr(sdev)	atomic_read(&sdev->ua_por_ctr)
 
 #define MODULE_ALIAS_SCSI_DEVICE(type) \
 	MODULE_ALIAS("scsi:t-" __stringify(type) "*")