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authorNetanel Belgazal <netanel@amazon.com>2017-06-11 15:42:43 +0300
committerDavid S. Miller <davem@davemloft.net>2017-06-11 16:36:45 -0400
commita77c1aafcc906f657d1a0890c1d898be9ee1d5c9 (patch)
treea63a4ac44158e16d8a523ac42dc0fefbc98f5fbd /drivers
parentb87fa0fafef4b16495740432f4eb8262efa500d0 (diff)
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: 1738cd3ed342 ("Add a driver for Amazon Elastic Network Adapters (ENA)") Signed-off-by: Netanel Belgazal <netanel@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/ethernet/amazon/ena/ena_com.c21
1 files 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 08d11cede9c9..e1c2fab6292f 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(&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);
}