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From:   Can Guo <cang@codeaurora.org>
To:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        hongwus@codeaurora.org, rnayak@codeaurora.org,
        linux-scsi@vger.kernel.org, kernel-team@android.com,
        saravanak@google.com, salyzyn@google.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>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        linux-kernel@vger.kernel.org (open list),
        linux-arm-kernel@lists.infradead.org (moderated list:ARM/Mediatek SoC
        support),
        linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek SoC
        support)
Subject: [PATCH v4 1/2] scsi: ufs: Fix a possible NULL pointer issue
Date:   Wed, 13 Jan 2021 05:57:08 -0800
Message-Id: <1610546230-14732-2-git-send-email-cang@codeaurora.org>
In-Reply-To: <1610546230-14732-1-git-send-email-cang@codeaurora.org>
References: <1610546230-14732-1-git-send-email-cang@codeaurora.org>
Precedence: bulk

During system resume/suspend, hba could be NULL. In this case, do not touch
eh_sem.

Fixes: 88a92d6ae4fe ("scsi: ufs: Serialize eh_work with system PM events and async scan")

Acked-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 53fd59c..969aed9 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -94,6 +94,8 @@
 		       16, 4, buf, __len, false);                        \
 } while (0)
 
+static bool early_suspend;
+
 int ufshcd_dump_regs(struct ufs_hba *hba, size_t offset, size_t len,
 		     const char *prefix)
 {
@@ -8953,8 +8955,14 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
 	int ret = 0;
 	ktime_t start = ktime_get();
 
+	if (!hba) {
+		early_suspend = true;
+		return 0;
+	}
+
 	down(&hba->eh_sem);
-	if (!hba || !hba->is_powered)
+
+	if (!hba->is_powered)
 		return 0;
 
 	if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) ==
@@ -9002,9 +9010,12 @@ int ufshcd_system_resume(struct ufs_hba *hba)
 	int ret = 0;
 	ktime_t start = ktime_get();
 
-	if (!hba) {
-		up(&hba->eh_sem);
+	if (!hba)
 		return -EINVAL;
+
+	if (unlikely(early_suspend)) {
+		early_suspend = false;
+		down(&hba->eh_sem);
 	}
 
 	if (!hba->is_powered || pm_runtime_suspended(hba->dev))
-- 
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