Re: [PATCH v1] scsi: ufs: Fix deadlock issue in ufshcd_wait_for_doorbell_clr()

[Bart Van Assche]

On 12/13/21 3:00 PM, Bean Huo wrote:
> Call shost_for_each_device() with host->host_lock is held will cause
> a deadlock situation, which will cause the system to stall (the log
> as follow). Fix this issue by narrowing the scope of the lock.

Hi Bean,

As you probably know I do not have access to a test setup that supports clock
scaling. Has the following patch been considered?

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 6d692aae67ce..244eddf0caf8 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1084,7 +1084,9 @@ static u32 ufshcd_pending_cmds(struct ufs_hba *hba)
 	struct scsi_device *sdev;
 	u32 pending = 0;

-	shost_for_each_device(sdev, hba->host)
+	lockdep_assert_held(hba->host->host_lock);
+
+	__shost_for_each_device(sdev, hba->host)
 		pending += sbitmap_weight(&sdev->budget_map);

 	return pending;

Thanks,

Bart.