Re: [PATCH v2 08/10] scsi: ufs: make sure all interrupts are processed

[Subhash Jadavani]

On 2018-05-03 04:07, Asutosh Das wrote:

From: Venkat Gopalakrishnan 

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 
Signed-off-by: Asutosh Das 
---
 drivers/scsi/ufs/ufshcd.c | 27 +++
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c35a076..09b7a3f 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5383,19 +5383,30 @@ 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;
 }


Looks good to me.
Reviewed-by: Subhash Jadavani 

--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

[PATCH v2 08/10] scsi: ufs: make sure all interrupts are processed

[Asutosh Das]

From: Venkat Gopalakrishnan 

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 
Signed-off-by: Asutosh Das 
---
 drivers/scsi/ufs/ufshcd.c | 27 +++
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c35a076..09b7a3f 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5383,19 +5383,30 @@ 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;
 }
-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux 
Foundation Collaborative Project.