linux-kernel - [PATCH] scsi: ufs: fix livelock on ufshcd_clear_ua

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Date:   Wed, 16 Dec 2020 11:02:25 -0800
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
        kernel-team@...roid.com
Cc:     cang@...eaurora.org, alim.akhtar@...sung.com, avri.altman@....com,
        bvanassche@....org, martin.petersen@...cle.com,
        stanley.chu@...iatek.com, Jaegeuk Kim <jaegeuk@...gle.com>
Subject: [PATCH] scsi: ufs: fix livelock on ufshcd_clear_ua_wlun

From: Jaegeuk Kim <jaegeuk@...gle.com>

This fixes the below livelock which is caused by calling a scsi command before
ufshcd_scsi_unblock_requests() in ufshcd_ungate_work().

Workqueue: ufs_clk_gating_0 ufshcd_ungate_work
Call trace:
 __switch_to+0x298/0x2bc
 __schedule+0x59c/0x760
 schedule+0xac/0xf0
 schedule_timeout+0x44/0x1b4
 io_schedule_timeout+0x44/0x68
 wait_for_common_io+0x7c/0x100
 wait_for_completion_io+0x14/0x20
 blk_execute_rq+0x94/0xd0
 __scsi_execute+0x100/0x1c0
 ufshcd_clear_ua_wlun+0x124/0x1c8
 ufshcd_host_reset_and_restore+0x1d0/0x2cc
 ufshcd_link_recovery+0xac/0x134
 ufshcd_uic_hibern8_exit+0x1e8/0x1f0
 ufshcd_ungate_work+0xac/0x130
 process_one_work+0x270/0x47c
 worker_thread+0x27c/0x4d8
 kthread+0x13c/0x320
 ret_from_fork+0x10/0x18

Fixes: 1918651f2d7e ("scsi: ufs: Clear UAC for RPMB after ufshcd resets")
Signed-off-by: Jaegeuk Kim <jaegeuk@...gle.com>
---
 drivers/scsi/ufs/ufshcd.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index e221add25a7e..b0998db1b781 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1603,6 +1603,7 @@ static void ufshcd_ungate_work(struct work_struct *work)
 	}
 unblock_reqs:
 	ufshcd_scsi_unblock_requests(hba);
+	ufshcd_clear_ua_wluns(hba);
 }
 
 /**
@@ -6913,7 +6914,7 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba)
 
 	/* Establish the link again and restore the device */
 	err = ufshcd_probe_hba(hba, false);
-	if (!err)
+	if (!err && !hba->clk_gating.is_suspended)
 		ufshcd_clear_ua_wluns(hba);
 out:
 	if (err)
@@ -8745,6 +8746,7 @@ static int ufshcd_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 		ufshcd_resume_clkscaling(hba);
 	hba->clk_gating.is_suspended = false;
 	hba->dev_info.b_rpm_dev_flush_capable = false;
+	ufshcd_clear_ua_wluns(hba);
 	ufshcd_release(hba);
 out:
 	if (hba->dev_info.b_rpm_dev_flush_capable) {
@@ -8855,6 +8857,8 @@ static int ufshcd_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 		cancel_delayed_work(&hba->rpm_dev_flush_recheck_work);
 	}
 
+	ufshcd_clear_ua_wluns(hba);
+
 	/* Schedule clock gating in case of no access to UFS device yet */
 	ufshcd_release(hba);
 
-- 
2.29.2.729.g45daf8777d-goog