[PATCH net-next 1/8] net: ena: fix rare uncompleted admin command false alarm

[netanel]

From: Netanel Belgazal 

The current flow to detect admin completion is:
while (command_not_completed) {
if (timeout)
error

check_for_completion()
sleep()
   }
So in case the sleep took more than the timeout
(in case the thread/workqueue was not scheduled due to higher priority
task or prolonged VMexit), the driver can detect a stall even if
the completion is present.

The fix changes the order of this function to first check for
completion and only after that check if the timeout expired.

Signed-off-by: Netanel Belgazal 
---
 drivers/net/ethernet/amazon/ena/ena_com.c | 21 +++--
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c 
b/drivers/net/ethernet/amazon/ena/ena_com.c
index 08d11ce..e1c2fab 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -508,15 +508,20 @@ static int ena_com_comp_status_to_errno(u8 comp_status)
 static int ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx 
*comp_ctx,
 struct ena_com_admin_queue 
*admin_queue)
 {
-   unsigned long flags;
-   u32 start_time;
+   unsigned long flags, timeout;
int ret;
 
-   start_time = ((u32)jiffies_to_usecs(jiffies));
+   timeout = jiffies + ADMIN_CMD_TIMEOUT_US;
+
+   while (1) {
+   spin_lock_irqsave(_queue->q_lock, flags);
+   ena_com_handle_admin_completion(admin_queue);
+   spin_unlock_irqrestore(_queue->q_lock, flags);
 
-   while (comp_ctx->status == ENA_CMD_SUBMITTED) {
-   if u32)jiffies_to_usecs(jiffies)) - start_time) >
-   ADMIN_CMD_TIMEOUT_US) {
+   if (comp_ctx->status != ENA_CMD_SUBMITTED)
+   break;
+
+   if (time_is_before_jiffies(timeout)) {
pr_err("Wait for completion (polling) timeout\n");
/* ENA didn't have any completion */
spin_lock_irqsave(_queue->q_lock, flags);
@@ -528,10 +533,6 @@ static int 
ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx *comp_c
goto err;
}
 
-   spin_lock_irqsave(_queue->q_lock, flags);
-   ena_com_handle_admin_completion(admin_queue);
-   spin_unlock_irqrestore(_queue->q_lock, flags);
-
msleep(100);
}
 
-- 
2.7.4

[PATCH net-next 1/8] net: ena: fix rare uncompleted admin command false alarm

[netanel]

From: Netanel Belgazal 

The current flow to detect admin completion is:
while (command_not_completed) {
if (timeout)
error

check_for_completion()
sleep()
   }
So in case the sleep took more than the timeout
(in case the thread/workqueue was not scheduled due to higher priority
task or prolonged VMexit), the driver can detect a stall even if
the completion is present.

The fix changes the order of this function to first check for
completion and only after that check if the timeout expired.

Signed-off-by: Netanel Belgazal 
---
 drivers/net/ethernet/amazon/ena/ena_com.c | 21 +++--
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c 
b/drivers/net/ethernet/amazon/ena/ena_com.c
index 08d11ce..e1c2fab 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -508,15 +508,20 @@ static int ena_com_comp_status_to_errno(u8 comp_status)
 static int ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx 
*comp_ctx,
 struct ena_com_admin_queue 
*admin_queue)
 {
-   unsigned long flags;
-   u32 start_time;
+   unsigned long flags, timeout;
int ret;
 
-   start_time = ((u32)jiffies_to_usecs(jiffies));
+   timeout = jiffies + ADMIN_CMD_TIMEOUT_US;
+
+   while (1) {
+   spin_lock_irqsave(_queue->q_lock, flags);
+   ena_com_handle_admin_completion(admin_queue);
+   spin_unlock_irqrestore(_queue->q_lock, flags);
 
-   while (comp_ctx->status == ENA_CMD_SUBMITTED) {
-   if u32)jiffies_to_usecs(jiffies)) - start_time) >
-   ADMIN_CMD_TIMEOUT_US) {
+   if (comp_ctx->status != ENA_CMD_SUBMITTED)
+   break;
+
+   if (time_is_before_jiffies(timeout)) {
pr_err("Wait for completion (polling) timeout\n");
/* ENA didn't have any completion */
spin_lock_irqsave(_queue->q_lock, flags);
@@ -528,10 +533,6 @@ static int 
ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx *comp_c
goto err;
}
 
-   spin_lock_irqsave(_queue->q_lock, flags);
-   ena_com_handle_admin_completion(admin_queue);
-   spin_unlock_irqrestore(_queue->q_lock, flags);
-
msleep(100);
}
 
-- 
2.7.4

[PATCH net-next 1/8] net: ena: fix rare uncompleted admin command false alarm

[netanel]

From: Netanel Belgazal 

The current flow to detect admin completion is:
while (command_not_completed) {
if (timeout)
error

check_for_completion()
sleep()
   }
So in case the sleep took more than the timeout
(in case the thread/workqueue was not scheduled due to higher priority
task or prolonged VMexit), the driver can detect a stall even if
the completion is present.

The fix changes the order of this function to first check for
completion and only after that check if the timeout expired.

Signed-off-by: Netanel Belgazal 
---
 drivers/net/ethernet/amazon/ena/ena_com.c | 21 +++--
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_com.c 
b/drivers/net/ethernet/amazon/ena/ena_com.c
index 08d11ce..e1c2fab 100644
--- a/drivers/net/ethernet/amazon/ena/ena_com.c
+++ b/drivers/net/ethernet/amazon/ena/ena_com.c
@@ -508,15 +508,20 @@ static int ena_com_comp_status_to_errno(u8 comp_status)
 static int ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx 
*comp_ctx,
 struct ena_com_admin_queue 
*admin_queue)
 {
-   unsigned long flags;
-   u32 start_time;
+   unsigned long flags, timeout;
int ret;
 
-   start_time = ((u32)jiffies_to_usecs(jiffies));
+   timeout = jiffies + ADMIN_CMD_TIMEOUT_US;
+
+   while (1) {
+   spin_lock_irqsave(_queue->q_lock, flags);
+   ena_com_handle_admin_completion(admin_queue);
+   spin_unlock_irqrestore(_queue->q_lock, flags);
 
-   while (comp_ctx->status == ENA_CMD_SUBMITTED) {
-   if u32)jiffies_to_usecs(jiffies)) - start_time) >
-   ADMIN_CMD_TIMEOUT_US) {
+   if (comp_ctx->status != ENA_CMD_SUBMITTED)
+   break;
+
+   if (time_is_before_jiffies(timeout)) {
pr_err("Wait for completion (polling) timeout\n");
/* ENA didn't have any completion */
spin_lock_irqsave(_queue->q_lock, flags);
@@ -528,10 +533,6 @@ static int 
ena_com_wait_and_process_admin_cq_polling(struct ena_comp_ctx *comp_c
goto err;
}
 
-   spin_lock_irqsave(_queue->q_lock, flags);
-   ena_com_handle_admin_completion(admin_queue);
-   spin_unlock_irqrestore(_queue->q_lock, flags);
-
msleep(100);
}
 
-- 
2.7.4