net: aquantia: fix out of memory condition on rx side

On embedded environments with hard memory limits it is a normal although
rare case when skb can't be allocated on rx part under high traffic.

In such OOM cases napi_complete_done() was not called.
So the napi object became in an invalid state like it is "scheduled".
Kernel do not re-schedules the poll of that napi object.

Consequently, kernel can not remove that object the system hangs on
`ifconfig down` waiting for a poll.

We are fixing this by gracefully closing napi poll routine with correct
invocation of napi_complete_done.

This was reproduced with artificially failing the allocation of skb to
simulate an "out of memory" error case and check that traffic does
not get stuck.

Fixes: 970a2e9864b0 ("net: ethernet: aquantia: Vector operations")
Signed-off-by: Igor Russkikh <igor.russkikh@aquantia.com>
Signed-off-by: Dmitry Bogdanov <dmitry.bogdanov@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_vec.c b/drivers/net/ethernet/aquantia/atlantic/aq_vec.c
index 715685aa48c3..28892b8acd0e 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_vec.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_vec.c
@@ -86,6 +86,7 @@ static int aq_vec_poll(struct napi_struct *napi, int budget)
                         }
                 }
 
+err_exit:
                 if (!was_tx_cleaned)
                         work_done = budget;
 
@@ -95,7 +96,7 @@ static int aq_vec_poll(struct napi_struct *napi, int budget)
                                         1U << self->aq_ring_param.vec_idx);
                 }
         }
-err_exit:
+
         return work_done;
 }