On 1/31/2018 1:09 PM, Avri Altman wrote:
Hi,
Can you elaborate how this can even happen?
Isn't the interrupt aggregation capability should attend for those cases?
Thanks,
Avri
-----Original Message-----
From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi-
owner@xxxxxxxxxxxxxxx] On Behalf Of Asutosh Das
Sent: Tuesday, January 30, 2018 6:54 AM
To: subhashj@xxxxxxxxxxxxxx; cang@xxxxxxxxxxxxxx;
vivek.gautam@xxxxxxxxxxxxxx; rnayak@xxxxxxxxxxxxxx;
vinholikatti@xxxxxxxxx; jejb@xxxxxxxxxxxxxxxxxx;
martin.petersen@xxxxxxxxxx
Cc: linux-scsi@xxxxxxxxxxxxxxx; Venkat Gopalakrishnan
<venkatg@xxxxxxxxxxxxxx>; Asutosh Das <asutoshd@xxxxxxxxxxxxxx>; open
list <linux-kernel@xxxxxxxxxxxxxxx>
Subject: [PATCH 1/1] scsi: ufs: make sure all interrupts are processed
From: Venkat Gopalakrishnan <venkatg@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxx>
Signed-off-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
---
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
8af2af3..58d81de 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5357,19 +5357,30 @@ 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.
Hi
yes - interrupt aggregation makes sense here. But there were some
performance concerns with it; well, I don't have the data to back that
up now though.
However, I can code it up and check it.
Will post it in some time.
-asd
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a
Linux Foundation Collaborative Project
