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From: Can Guo <cang@codeaurora.org>
To: asutoshd@codeaurora.org, nguyenb@codeaurora.org,
	hongwus@codeaurora.org, ziqichen@codeaurora.org,
	linux-scsi@vger.kernel.org, kernel-team@android.com,
	cang@codeaurora.org
Cc: Alim Akhtar <alim.akhtar@samsung.com>,
	Avri Altman <avri.altman@wdc.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Stanley Chu <stanley.chu@mediatek.com>,
	Bean Huo <beanhuo@micron.com>, Jaegeuk Kim <jaegeuk@kernel.org>,
	linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v3 8/9] scsi: ufs: Update the fast abort path in ufshcd_abort() for PM requests
Date: Wed,  9 Jun 2021 21:43:36 -0700	[thread overview]
Message-ID: <1623300218-9454-9-git-send-email-cang@codeaurora.org> (raw)
In-Reply-To: <1623300218-9454-1-git-send-email-cang@codeaurora.org>

If PM requests fail during runtime suspend/resume, RPM framework saves the
error to dev->power.runtime_error. Before the runtime_error gets cleared,
runtime PM on this specific device won't work again, leaving the device
either runtime active or runtime suspended permanently.

When task abort happens to a PM request sent during runtime suspend/resume,
even if it can be successfully aborted, RPM framework anyways saves the
(TIMEOUT) error. In this situation, we can leverage error handling to
recover and clear the runtime_error. So, let PM requests take the fast
abort path in ufshcd_abort().

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 38 ++++++++++++++++++++++----------------
 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 861942b..cf24ec2 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -2737,7 +2737,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 		 * err handler blocked for too long. So, just fail the scsi cmd
 		 * sent from PM ops, err handler can recover PM error anyways.
 		 */
-		if (hba->wl_pm_op_in_progress) {
+		if (cmd->request->rq_flags & RQF_PM) {
 			hba->force_reset = true;
 			set_host_byte(cmd, DID_BAD_TARGET);
 			cmd->scsi_done(cmd);
@@ -2760,7 +2760,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 	}
 
 	if (unlikely(test_bit(tag, &hba->outstanding_reqs))) {
-		if (hba->wl_pm_op_in_progress) {
+		if (cmd->request->rq_flags & RQF_PM) {
 			set_host_byte(cmd, DID_BAD_TARGET);
 			cmd->scsi_done(cmd);
 		} else {
@@ -6985,11 +6985,14 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 	int err = 0;
 	struct ufshcd_lrb *lrbp;
 	u32 reg;
+	bool need_eh = false;
 
 	host = cmd->device->host;
 	hba = shost_priv(host);
 	tag = cmd->request->tag;
 	lrbp = &hba->lrb[tag];
+
+	dev_info(hba->dev, "%s: Device abort task at tag %d\n", __func__, tag);
 	if (!ufshcd_valid_tag(hba, tag)) {
 		dev_err(hba->dev,
 			"%s: invalid command tag %d: cmd=0x%p, cmd->request=0x%p",
@@ -7007,9 +7010,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 		goto out;
 	}
 
-	/* Print Transfer Request of aborted task */
-	dev_info(hba->dev, "%s: Device abort task at tag %d\n", __func__, tag);
-
 	/*
 	 * Print detailed info about aborted request.
 	 * As more than one request might get aborted at the same time,
@@ -7037,21 +7037,21 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 	}
 
 	/*
-	 * Task abort to the device W-LUN is illegal. When this command
-	 * will fail, due to spec violation, scsi err handling next step
-	 * will be to send LU reset which, again, is a spec violation.
-	 * To avoid these unnecessary/illegal steps, first we clean up
-	 * the lrb taken by this cmd and re-set it in outstanding_reqs,
-	 * then queue the eh_work and bail.
+	 * This fast path guarantees the cmd always gets aborted successfully,
+	 * meanwhile it invokes the error handler. It allows contexts, which
+	 * are blocked by this cmd, to fail fast. It serves multiple purposes:
+	 * #1 To avoid unnecessary/illagal abort attempts to the W-LU.
+	 * #2 To avoid live lock between eh_work and specific contexts, i.e.,
+	 *    suspend/resume and eh_work itself.
+	 * #3 To let eh_work recover runtime PM error in case abort happens
+	 *    to cmds sent from runtime suspend/resume ops.
 	 */
-	if (lrbp->lun == UFS_UPIU_UFS_DEVICE_WLUN) {
+	if (lrbp->lun == UFS_UPIU_UFS_DEVICE_WLUN ||
+	    (cmd->request->rq_flags & RQF_PM)) {
 		ufshcd_update_evt_hist(hba, UFS_EVT_ABORT, lrbp->lun);
 		__ufshcd_transfer_req_compl(hba, (1UL << tag));
 		set_bit(tag, &hba->outstanding_reqs);
-		spin_lock_irqsave(host->host_lock, flags);
-		hba->force_reset = true;
-		ufshcd_schedule_eh_work(hba);
-		spin_unlock_irqrestore(host->host_lock, flags);
+		need_eh = true;
 		goto out;
 	}
 
@@ -7065,6 +7065,12 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 cleanup:
 		__ufshcd_transfer_req_compl(hba, (1UL << tag));
 out:
+		if (cmd->request->rq_flags & RQF_PM || need_eh) {
+			spin_lock_irqsave(host->host_lock, flags);
+			hba->force_reset = true;
+			ufshcd_schedule_eh_work(hba);
+			spin_unlock_irqrestore(host->host_lock, flags);
+		}
 		err = SUCCESS;
 	} else {
 		dev_err(hba->dev, "%s: failed with err %d\n", __func__, err);
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.


  parent reply	other threads:[~2021-06-10  4:44 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-10  4:43 [PATCH v3 0/9] Complementary changes for error handling Can Guo
2021-06-10  4:43 ` [PATCH v3 1/9] scsi: ufs: Differentiate status between hba pm ops and wl pm ops Can Guo
2021-06-10 11:15   ` Adrian Hunter
2021-06-11  0:53     ` Can Guo
2021-06-11 20:40   ` Bart Van Assche
2021-06-12  6:20     ` Can Guo
2021-06-16 17:50   ` Bart Van Assche
2021-06-23  1:32     ` Can Guo
2021-06-10  4:43 ` [PATCH v3 2/9] scsi: ufs: Update the return value of supplier " Can Guo
2021-06-10  4:43 ` [PATCH v3 3/9] scsi: ufs: Enable IRQ after enabling clocks in error handling preparation Can Guo
2021-06-10  4:43 ` [PATCH v3 4/9] scsi: ufs: Complete the cmd before returning in queuecommand Can Guo
2021-06-11 20:52   ` Bart Van Assche
2021-06-12  7:38     ` Can Guo
2021-06-12 15:50       ` Bart Van Assche
2021-06-13 13:30         ` Can Guo
2021-06-10  4:43 ` [PATCH v3 5/9] scsi: ufs: Simplify error handling preparation Can Guo
2021-06-10 12:30   ` Adrian Hunter
2021-06-11  3:01     ` Can Guo
2021-06-11 20:58       ` Bart Van Assche
2021-06-12  6:46         ` Can Guo
2021-06-12  9:49           ` Can Guo
2021-06-10  4:43 ` [PATCH v3 6/9] scsi: ufs: Update ufshcd_recover_pm_error() Can Guo
2021-06-10  4:43 ` [PATCH v3 7/9] scsi: ufs: Let host_sem cover the entire system suspend/resume Can Guo
2021-06-10 13:32   ` Adrian Hunter
2021-06-11  3:06     ` Can Guo
2021-06-11 21:00   ` Bart Van Assche
2021-06-12  6:46     ` Can Guo
2021-06-10  4:43 ` Can Guo [this message]
2021-06-11 21:02   ` [PATCH v3 8/9] scsi: ufs: Update the fast abort path in ufshcd_abort() for PM requests Bart Van Assche
2021-06-12  7:07     ` Can Guo
2021-06-12 16:50       ` Bart Van Assche
2021-06-13 14:42         ` Can Guo
2021-06-14 18:49           ` Bart Van Assche
2021-06-15  2:36             ` Can Guo
2021-06-15  3:17               ` Can Guo
2021-06-15 18:25               ` Bart Van Assche
2021-06-16  4:00                 ` Can Guo
2021-06-16  4:40                   ` Bart Van Assche
2021-06-16  8:47                     ` Can Guo
2021-06-16 17:55                       ` Bart Van Assche
2021-06-23  1:34                         ` Can Guo
2021-06-10  4:43 ` [PATCH v3 9/9] scsi: ufs: Apply more limitations to user access Can Guo
2021-06-11 21:03   ` Bart Van Assche
2021-06-12  7:13     ` Can Guo

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