[PATCH v6 1/4] ufs: Serialize error handling and command submission

[Bart Van Assche <bvanassche@acm.org>]

With the legacy SCSI core holding the host lock was sufficient to serialize
queuecommand() calls and error handling. With scsi-mq a call to
blk_mq_quiesce() is required to wait until ongoing queuecommand calls have
finished. scsi_target_block() calls blk_mq_quiesce().

Cc: Bean Huo <beanhuo@micron.com>
Cc: Can Guo <cang@codeaurora.org>
Cc: Avri Altman <avri.altman@wdc.com>
Cc: Stanley Chu <stanley.chu@mediatek.com>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Fixes: d5038a13eca7 ("scsi: core: switch to scsi-mq by default")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/ufs/ufshcd.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b5966faf3e98..deca1538e184 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5306,6 +5306,8 @@ static bool ufshcd_quirk_dl_nac_errors(struct ufs_hba *hba)
 static void ufshcd_err_handler(struct work_struct *work)
 {
 	struct ufs_hba *hba;
+	struct scsi_device *sdev;
+	struct scsi_target *starget;
 	unsigned long flags;
 	u32 err_xfer = 0;
 	u32 err_tm = 0;
@@ -5314,10 +5316,19 @@ static void ufshcd_err_handler(struct work_struct *work)
 	bool needs_reset = false;
 
 	hba = container_of(work, struct ufs_hba, eh_work);
+	sdev = hba->sdev_ufs_device;
+	starget = sdev ? sdev->sdev_target : NULL;
 
 	pm_runtime_get_sync(hba->dev);
 	ufshcd_hold(hba, false);
 
+	/*
+	 * Wait until ongoing ufshcd_queuecommand() calls have finished
+	 * without waiting for command completion.
+	 */
+	if (starget)
+		scsi_target_block(&starget->dev);
+
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	if (hba->ufshcd_state == UFSHCD_STATE_RESET)
 		goto out;
@@ -5426,6 +5437,8 @@ static void ufshcd_err_handler(struct work_struct *work)
 
 out:
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
+	if (starget)
+		scsi_target_unblock(&starget->dev, SDEV_RUNNING);
 	ufshcd_scsi_unblock_requests(hba);
 	ufshcd_release(hba);
 	pm_runtime_put_sync(hba->dev);