scsi: ufs: Fix a possible NULL pointer issue

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")
Link: https://lore.kernel.org/r/1610594010-7254-2-git-send-email-cang@codeaurora.org
Acked-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index cc8d00343b9efc0d2a1cd36c127788f8f5586e48..52e6e618b317b06170c730c141b79d39a1ae5a8f 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -95,6 +95,8 @@
                       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)
 {
@@ -8952,8 +8954,14 @@ 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) ==
@@ -9001,9 +9009,12 @@ 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))