scsi: ufs: fix exception event handling

[ Upstream commit 2e3611e9546c2ed4def152a51dfd34e8dddae7a5 ]

The device can set the exception event bit in one of the response UPIU,
for example to notify the need for urgent BKOPs operation.  In such a
case, the host driver calls ufshcd_exception_event_handler to handle
this notification.  When trying to check the exception event status (for
finding the cause for the exception event), the device may be busy with
additional SCSI commands handling and may not respond within the 100ms
timeout.

To prevent that, we need to block SCSI commands during handling of
exception events and allow retransmissions of the query requests, in
case of timeout.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 86a3110c6d75118b02fccf3b6a2a45a2db1994ed..f857086ce2fa986a690b59012000443d67b5dc3c 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4012,6 +4012,7 @@ static void ufshcd_exception_event_handler(struct work_struct *work)
        hba = container_of(work, struct ufs_hba, eeh_work);
 
        pm_runtime_get_sync(hba->dev);
+       scsi_block_requests(hba->host);
        err = ufshcd_get_ee_status(hba, &status);
        if (err) {
                dev_err(hba->dev, "%s: failed to get exception status %d\n",
@@ -4025,6 +4026,7 @@ static void ufshcd_exception_event_handler(struct work_struct *work)
                ufshcd_bkops_exception_event_handler(hba);
 
 out:
+       scsi_unblock_requests(hba->host);
        pm_runtime_put_sync(hba->dev);
        return;
 }