scsi: ufs: Fix ufshcd_hold() caused scheduling while atomic

commit c63d6099a7959ecc919b2549dc6b71f53521f819 upstream.

The async version of ufshcd_hold(async == true), which is only called in
queuecommand path as for now, is expected to work in atomic context, thus
it should not sleep or schedule out. When it runs into the condition that
clocks are ON but link is still in hibern8 state, it should bail out
without flushing the clock ungate work.

Fixes: f2a785ac2312 ("scsi: ufshcd: Fix race between clk scaling and ungate work")
Link: https://lore.kernel.org/r/1581392451-28743-6-git-send-email-cang@codeaurora.org
Reviewed-by: Hongwu Su <hongwus@codeaurora.org>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b3dee24917a868aeecbcf9cf12e914c1256dedf9..d91209ba18c8631b45dcaf2e78eb94631a323c70 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1563,6 +1563,11 @@ start:
                 */
                if (ufshcd_can_hibern8_during_gating(hba) &&
                    ufshcd_is_link_hibern8(hba)) {
+                       if (async) {
+                               rc = -EAGAIN;
+                               hba->clk_gating.active_reqs--;
+                               break;
+                       }
                        spin_unlock_irqrestore(hba->host->host_lock, flags);
                        flush_work(&hba->clk_gating.ungate_work);
                        spin_lock_irqsave(hba->host->host_lock, flags);