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 5d8f6356c556df7c814957822d10d06ed08132f6..088c1a5dd1cf5c7a4068b01ae7597c4fb30c1939 100644 (file)
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -1542,6 +1542,11 @@ 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);