Patch "scsi: ufs: Try to save power mode change and UIC cmd completion timeout" has been added to the 5.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    scsi: ufs: Try to save power mode change and UIC cmd completion timeout

to the 5.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     scsi-ufs-try-to-save-power-mode-change-and-uic-cmd-c.patch
and it can be found in the queue-5.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6c3dd924771d317c821f99b64aacdd60463c36a9
Author: Can Guo <cang@xxxxxxxxxxxxxx>
Date:   Mon Nov 2 22:24:40 2020 -0800

    scsi: ufs: Try to save power mode change and UIC cmd completion timeout
    
    [ Upstream commit 0f52fcb99ea2738a0a0f28e12cf4dd427069dd2a ]
    
    Use the uic_cmd->cmd_active as a flag to track the lifecycle of an UIC cmd.
    The flag is set before sending the UIC cmd and cleared in IRQ handler. When
    a PMC or UIC cmd completion timeout happens, if the flag is not set,
    instead of returning timeout error, we still treat it as a successful
    operation.  This is to deal with the scenario in which completion has been
    raised but the one waiting for the completion cannot be awaken in time due
    to kernel scheduling problem.
    
    Link: https://lore.kernel.org/r/1604384682-15837-3-git-send-email-cang@xxxxxxxxxxxxxx
    Reviewed-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
    Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
    Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 0cb3e71f30ffb..54928a837dad0 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -2100,10 +2100,20 @@ ufshcd_wait_for_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	unsigned long flags;
 
 	if (wait_for_completion_timeout(&uic_cmd->done,
-					msecs_to_jiffies(UIC_CMD_TIMEOUT)))
+					msecs_to_jiffies(UIC_CMD_TIMEOUT))) {
 		ret = uic_cmd->argument2 & MASK_UIC_COMMAND_RESULT;
-	else
+	} else {
 		ret = -ETIMEDOUT;
+		dev_err(hba->dev,
+			"uic cmd 0x%x with arg3 0x%x completion timeout\n",
+			uic_cmd->command, uic_cmd->argument3);
+
+		if (!uic_cmd->cmd_active) {
+			dev_err(hba->dev, "%s: UIC cmd has been completed, return the result\n",
+				__func__);
+			ret = uic_cmd->argument2 & MASK_UIC_COMMAND_RESULT;
+		}
+	}
 
 	spin_lock_irqsave(hba->host->host_lock, flags);
 	hba->active_uic_cmd = NULL;
@@ -2135,6 +2145,7 @@ __ufshcd_send_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd,
 	if (completion)
 		init_completion(&uic_cmd->done);
 
+	uic_cmd->cmd_active = 1;
 	ufshcd_dispatch_uic_cmd(hba, uic_cmd);
 
 	return 0;
@@ -3774,10 +3785,18 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 		dev_err(hba->dev,
 			"pwr ctrl cmd 0x%x with mode 0x%x completion timeout\n",
 			cmd->command, cmd->argument3);
+
+		if (!cmd->cmd_active) {
+			dev_err(hba->dev, "%s: Power Mode Change operation has been completed, go check UPMCRS\n",
+				__func__);
+			goto check_upmcrs;
+		}
+
 		ret = -ETIMEDOUT;
 		goto out;
 	}
 
+check_upmcrs:
 	status = ufshcd_get_upmcrs(hba);
 	if (status != PWR_LOCAL) {
 		dev_err(hba->dev,
@@ -4887,11 +4906,14 @@ static irqreturn_t ufshcd_uic_cmd_compl(struct ufs_hba *hba, u32 intr_status)
 			ufshcd_get_uic_cmd_result(hba);
 		hba->active_uic_cmd->argument3 =
 			ufshcd_get_dme_attr_val(hba);
+		if (!hba->uic_async_done)
+			hba->active_uic_cmd->cmd_active = 0;
 		complete(&hba->active_uic_cmd->done);
 		retval = IRQ_HANDLED;
 	}
 
 	if ((intr_status & UFSHCD_UIC_PWR_MASK) && hba->uic_async_done) {
+		hba->active_uic_cmd->cmd_active = 0;
 		complete(hba->uic_async_done);
 		retval = IRQ_HANDLED;
 	}
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 363589c0bd370..23f46c7b8cb28 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -64,6 +64,7 @@ enum dev_cmd_type {
  * @argument1: UIC command argument 1
  * @argument2: UIC command argument 2
  * @argument3: UIC command argument 3
+ * @cmd_active: Indicate if UIC command is outstanding
  * @done: UIC command completion
  */
 struct uic_command {
@@ -71,6 +72,7 @@ struct uic_command {
 	u32 argument1;
 	u32 argument2;
 	u32 argument3;
+	int cmd_active;
 	struct completion done;
 };