[PATCH net-next 1/8] net: ena: fix rare uncompleted admin command false alarm
flat view
STALE3424d
From: <hidden>
Date: 2017-06-08 21:47:36
Subsystem:
amazon ethernet drivers, networking drivers, the rest · Maintainers:
Arthur Kiyanovski, David Arinzon, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Revision v1 of 4 in this series.
From: Netanel Belgazal <redacted>
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 <redacted>
---
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(&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); }
--
2.7.4