diff mbox series

[4.14,10/24] scsi: ufs: make sure all interrupts are processed

Message ID 20200421124017.272694-11-lee.jones@linaro.org
State Superseded
Headers show
Series [4.14,01/24] drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem | expand

Commit Message

Lee Jones April 21, 2020, 12:40 p.m. UTC 
From: Venkat Gopalakrishnan <venkatg@codeaurora.org>

[ Upstream commit 7f6ba4f12e6cbfdefbb95cfd8fc67ece6c15d799 ]

As multiple requests are submitted to the ufs host controller in
parallel there could be instances where the command completion interrupt
arrives later for a request that is already processed earlier as the
corresponding doorbell was cleared when handling the previous
interrupt. Read the interrupt status in a loop after processing the
received interrupt to catch such interrupts and handle it.

Signed-off-by: Venkat Gopalakrishnan <venkatg@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: Lee Jones <lee.jones@linaro.org>
---
 drivers/scsi/ufs/ufshcd.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c350453246952..f4f2c4f22b5f5 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5366,19 +5366,30 @@  static irqreturn_t ufshcd_intr(int irq, void *__hba)
 	u32 intr_status, enabled_intr_status;
 	irqreturn_t retval = IRQ_NONE;
 	struct ufs_hba *hba = __hba;
+	int retries = hba->nutrs;
 
 	spin_lock(hba->host->host_lock);
 	intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
-	enabled_intr_status =
-		intr_status & ufshcd_readl(hba, REG_INTERRUPT_ENABLE);
 
-	if (intr_status)
-		ufshcd_writel(hba, intr_status, REG_INTERRUPT_STATUS);
+	/*
+	 * There could be max of hba->nutrs reqs in flight and in worst case
+	 * if the reqs get finished 1 by 1 after the interrupt status is
+	 * read, make sure we handle them by checking the interrupt status
+	 * again in a loop until we process all of the reqs before returning.
+	 */
+	do {
+		enabled_intr_status =
+			intr_status & ufshcd_readl(hba, REG_INTERRUPT_ENABLE);
+		if (intr_status)
+			ufshcd_writel(hba, intr_status, REG_INTERRUPT_STATUS);
+		if (enabled_intr_status) {
+			ufshcd_sl_intr(hba, enabled_intr_status);
+			retval = IRQ_HANDLED;
+		}
+
+		intr_status = ufshcd_readl(hba, REG_INTERRUPT_STATUS);
+	} while (intr_status && --retries);
 
-	if (enabled_intr_status) {
-		ufshcd_sl_intr(hba, enabled_intr_status);
-		retval = IRQ_HANDLED;
-	}
 	spin_unlock(hba->host->host_lock);
 	return retval;
 }