linux-kernel - [PATCH v2 4/4] scsi: ufs: Complete pending requests in host reset and restore path

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Message-Id: <1574049061-11417-5-git-send-email-cang@qti.qualcomm.com>
Date:   Sun, 17 Nov 2019 19:51:00 -0800
From:   Can Guo <cang@....qualcomm.com>
To:     asutoshd@...eaurora.org, nguyenb@...eaurora.org,
        rnayak@...eaurora.org, linux-scsi@...r.kernel.org,
        kernel-team@...roid.com, saravanak@...gle.com, salyzyn@...gle.com,
        cang@...eaurora.org
Cc:     Alim Akhtar <alim.akhtar@...sung.com>,
        Avri Altman <avri.altman@....com>,
        Pedro Sousa <pedrom.sousa@...opsys.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Stanley Chu <stanley.chu@...iatek.com>,
        Bean Huo <beanhuo@...ron.com>,
        Tomas Winkler <tomas.winkler@...el.com>,
        Venkat Gopalakrishnan <venkatg@...eaurora.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Arnd Bergmann <arnd@...db.de>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v2 4/4] scsi: ufs: Complete pending requests in host reset and restore path

From: Can Guo <cang@...eaurora.org>

In UFS host reset and restore path, before probe, we stop and start the
host controller once. After host controller is stopped, the pending
requests, if any, are cleared from the doorbell, but no completion IRQ
would be raised due to the hba is stopped.
These pending requests shall be completed along with the first NOP_OUT
command(as it is the first command which can raise a transfer completion
IRQ) sent during probe.
Since the OCSs of these pending requests are not SUCCESS(because they are
not yet literally finished), their UPIUs shall be dumped. When there are
multiple pending requests, the UPIU dump can be overwhelming and may lead
to stability issues because it is in atomic context.
Therefore, before probe, complete these pending requests right after host
controller is stopped and silence the UPIU dump from them.

Signed-off-by: Can Guo <cang@...eaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 24 ++++++++++--------------
 drivers/scsi/ufs/ufshcd.h |  2 ++
 2 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 5950a7c..b92a3f4 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4845,7 +4845,7 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev)
 		break;
 	} /* end of switch */
 
-	if (host_byte(result) != DID_OK)
+	if ((host_byte(result) != DID_OK) && !hba->silence_err_logs)
 		ufshcd_print_trs(hba, 1 << lrbp->task_tag, true);
 	return result;
 }
@@ -5404,8 +5404,8 @@ static void ufshcd_err_handler(struct work_struct *work)
 
 	/*
 	 * if host reset is required then skip clearing the pending
-	 * transfers forcefully because they will automatically get
-	 * cleared after link startup.
+	 * transfers forcefully because they will get cleared during
+	 * host reset and restore
 	 */
 	if (needs_reset)
 		goto skip_pending_xfer_clear;
@@ -6333,9 +6333,15 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
 	int err;
 	unsigned long flags;
 
-	/* Reset the host controller */
+	/*
+	 * Stop the host controller and complete the requests
+	 * cleared by h/w
+	 */
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	ufshcd_hba_stop(hba, false);
+	hba->silence_err_logs = true;
+	ufshcd_complete_requests(hba);
+	hba->silence_err_logs = false;
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 
 	/* scale up clocks to max frequency before full reinitialization */
@@ -6369,7 +6375,6 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
 static int ufshcd_reset_and_restore(struct ufs_hba *hba)
 {
 	int err = 0;
-	unsigned long flags;
 	int retries = MAX_HOST_RESET_RETRIES;
 
 	do {
@@ -6379,15 +6384,6 @@ static int ufshcd_reset_and_restore(struct ufs_hba *hba)
 		err = ufshcd_host_reset_and_restore(hba);
 	} while (err && --retries);
 
-	/*
-	 * After reset the door-bell might be cleared, complete
-	 * outstanding requests in s/w here.
-	 */
-	spin_lock_irqsave(hba->host->host_lock, flags);
-	ufshcd_transfer_req_compl(hba);
-	ufshcd_tmc_handler(hba);
-	spin_unlock_irqrestore(hba->host->host_lock, flags);
-
 	return err;
 }
 
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index e0fe247..1e51034 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -513,6 +513,7 @@ struct ufs_stats {
  * @uic_error: UFS interconnect layer error status
  * @saved_err: sticky error mask
  * @saved_uic_err: sticky UIC error mask
+ * @silence_err_logs: flag to silence error logs
  * @dev_cmd: ufs device management command information
  * @last_dme_cmd_tstamp: time stamp of the last completed DME command
  * @auto_bkops_enabled: to track whether bkops is enabled in device
@@ -670,6 +671,7 @@ struct ufs_hba {
 	u32 saved_err;
 	u32 saved_uic_err;
 	struct ufs_stats ufs_stats;
+	bool silence_err_logs;
 
 	/* Device management request data */
 	struct ufs_dev_cmd dev_cmd;
-- 
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