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Commit a77c1aaf authored by Netanel Belgazal's avatar Netanel Belgazal Committed by David S. Miller
Browse files

net: ena: fix rare uncompleted admin command false alarm 



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.

Fixes: 1738cd3e ("Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: default avatarNetanel Belgazal <netanel@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b87fa0fa

drivers/net/ethernet/amazon/ena/ena_com.c

+11 −10
Original line number Diff line number Diff line
@@ -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(&admin_queue->q_lock, flags);

		ena_com_handle_admin_completion(admin_queue);

		spin_unlock_irqrestore(&admin_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(&admin_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(&admin_queue->q_lock, flags);

		ena_com_handle_admin_completion(admin_queue);

		spin_unlock_irqrestore(&admin_queue->q_lock, flags);



		msleep(100);

	}