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[PATCH v1 10/15] scsi: ufs: fix error recovery after the hibern8 exit failure

From Yaniv Gardi <ygardi@codeaurora.org>
Newsgroups linux.kernel
Subject [PATCH v1 10/15] scsi: ufs: fix error recovery after the hibern8 exit failure
Date 2015-08-22 00:20 +0200
Message-ID <q02Pg-8pP-31@gated-at.bofh.it> (permalink)
References <q02Pf-8pP-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Hibern8 exit can be called from 3 different context:
    - ufshcd_hibern8_exit_work
    - ufshcd_ungate_work
    - runtime/system resume

If hibern8 exit fails for some reason then we try to bring the link to
active state by link startup but this recovery mechanism results into
deadlock or errors from first 2 context listed above. This change fixes
the recovery by adding proper error handling mechanism.

Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>

---
 drivers/scsi/ufs/ufshcd.c | 58 +++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 53 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 6d47e9e..30aec4d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -609,6 +609,11 @@ int ufshcd_hold(struct ufs_hba *hba, bool async)
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	hba->clk_gating.active_reqs++;
 
+	if (ufshcd_eh_in_progress(hba)) {
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+		return 0;
+	}
+
 start:
 	switch (hba->clk_gating.state) {
 	case CLKS_ON:
@@ -724,7 +729,8 @@ static void __ufshcd_release(struct ufs_hba *hba)
 	if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended
 		|| hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL
 		|| hba->lrb_in_use || hba->outstanding_tasks
-		|| hba->active_uic_cmd || hba->uic_async_done)
+		|| hba->active_uic_cmd || hba->uic_async_done
+		|| ufshcd_eh_in_progress(hba))
 		return;
 
 	hba->clk_gating.state = REQ_CLKS_OFF;
@@ -1362,6 +1368,13 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 		cmd->scsi_done(cmd);
 		goto out_unlock;
 	}
+
+	/* if error handling is in progress, don't issue commands */
+	if (ufshcd_eh_in_progress(hba)) {
+		set_host_byte(cmd, DID_ERROR);
+		cmd->scsi_done(cmd);
+		goto out_unlock;
+	}
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 
 	/* acquire the tag to make sure device cmds don't use it */
@@ -2392,6 +2405,31 @@ out:
 	return ret;
 }
 
+static int ufshcd_link_recovery(struct ufs_hba *hba)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	hba->ufshcd_state = UFSHCD_STATE_RESET;
+	ufshcd_set_eh_in_progress(hba);
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+	ret = ufshcd_host_reset_and_restore(hba);
+
+	spin_lock_irqsave(hba->host->host_lock, flags);
+	if (ret)
+		hba->ufshcd_state = UFSHCD_STATE_ERROR;
+	ufshcd_clear_eh_in_progress(hba);
+	spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+	if (ret)
+		dev_err(hba->dev, "%s: link recovery failed, err %d",
+			__func__, ret);
+
+	return ret;
+}
+
 static int __ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
 {
 	int ret;
@@ -2400,10 +2438,18 @@ static int __ufshcd_uic_hibern8_enter(struct ufs_hba *hba)
 	uic_cmd.command = UIC_CMD_DME_HIBER_ENTER;
 	ret = ufshcd_uic_pwr_ctrl(hba, &uic_cmd);
 
-	if (ret)
+	if (ret) {
 		dev_err(hba->dev, "%s: hibern8 enter failed. ret = %d",
 			__func__, ret);
 
+		/*
+		 * If link recovery fails then return error so that caller
+		 * don't retry the hibern8 enter again.
+		 */
+		if (ufshcd_link_recovery(hba))
+			ret = -ENOLINK;
+	}
+
 	return ret;
 }
 
@@ -2428,8 +2474,9 @@ static int ufshcd_uic_hibern8_exit(struct ufs_hba *hba)
 	uic_cmd.command = UIC_CMD_DME_HIBER_EXIT;
 	ret = ufshcd_uic_pwr_ctrl(hba, &uic_cmd);
 	if (ret) {
-		ufshcd_set_link_off(hba);
-		ret = ufshcd_host_reset_and_restore(hba);
+		dev_err(hba->dev, "%s: hibern8 exit failed. ret = %d",
+			__func__, ret);
+		ret = ufshcd_link_recovery(hba);
 	}
 
 	return ret;
@@ -4381,7 +4428,6 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
 	/* UFS device is also active now */
 	ufshcd_set_ufs_dev_active(hba);
 	ufshcd_force_reset_auto_bkops(hba);
-	hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
 	hba->wlun_dev_clr_ua = true;
 
 	if (ufshcd_get_max_pwr_mode(hba)) {
@@ -4395,6 +4441,8 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
 					__func__, ret);
 	}
 
+	/* set the state as operational after switching to desired gear */
+	hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
 	/*
 	 * If we are in error handling context or in power management callbacks
 	 * context, no need to scan the host
-- 
1.8.5.2

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Thread

[PATCH v1 00/15] Big fixes, retries, handle a race condition Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
  [PATCH v1 02/15] scsi: ufs: clear fields UTRD, UPIU req and rsp before new transfers Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
  [PATCH v1 03/15] scsi: ufs: verify command tag validity Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
  [PATCH v1 15/15] scsi: ufs: add wrapper for retrying sending query attribute Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
    Re: [PATCH v1 15/15] scsi: ufs: add wrapper for retrying sending  query attribute Rob Herring <robherring2@gmail.com> - 2015-08-23 23:10 +0200
      Re: [PATCH v1 15/15] scsi: ufs: add wrapper for retrying sending  query attribute ygardi@codeaurora.org - 2015-08-25 14:50 +0200
        Re: [PATCH v1 15/15] scsi: ufs: add wrapper for retrying sending  query attribute ygardi@codeaurora.org - 2015-08-25 15:30 +0200
  [PATCH v1 04/15] scsi: ufs: clear outstanding_request bit in case query timeout Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
  [PATCH v1 11/15] scsi: ufs: retry failed query flag requests Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
  [PATCH v1 14/15] scsi: ufs: commit descriptors before setting the doorbell Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
    Re: [PATCH v1 14/15] scsi: ufs: commit descriptors before setting the doorbell Rob Herring <robherring2@gmail.com> - 2015-08-23 23:20 +0200
      Re: [PATCH v1 14/15] scsi: ufs: commit descriptors before setting  the doorbell ygardi@codeaurora.org - 2015-08-25 14:40 +0200
        Re: [PATCH v1 14/15] scsi: ufs: commit descriptors before setting the doorbell Rob Herring <robherring2@gmail.com> - 2015-08-25 20:30 +0200
          Re: [PATCH v1 14/15] scsi: ufs: commit descriptors before setting  the doorbell ygardi@codeaurora.org - 2015-08-27 14:20 +0200
            Re: [PATCH v1 14/15] scsi: ufs: commit descriptors before setting the doorbell Rob Herring <robherring2@gmail.com> - 2015-08-27 19:30 +0200
              Re: [PATCH v1 14/15] scsi: ufs: commit descriptors before setting  the doorbell ygardi@codeaurora.org - 2015-08-30 12:00 +0200
        Re: [PATCH v1 14/15] scsi: ufs: commit descriptors before setting  the doorbell ygardi@codeaurora.org - 2015-08-27 14:30 +0200
          Re: [PATCH v1 14/15] scsi: ufs: commit descriptors before setting the doorbell Rob Herring <robherring2@gmail.com> - 2015-08-27 19:10 +0200
  [PATCH v1 10/15] scsi: ufs: fix error recovery after the hibern8 exit failure Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
  [PATCH v1 05/15] scsi: ufs: increase fDeviceInit query response timeout Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
  [PATCH v1 13/15] scsi: ufs: add missing memory barriers Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
  [PATCH v1 12/15] scsi: ufs: reduce the interrupts for power mode change requests Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200
  [PATCH v1 08/15] scsi: ufs: add retries to dme_peer get and set attribute Yaniv Gardi <ygardi@codeaurora.org> - 2015-08-22 00:20 +0200

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