| Message ID | 20170919173518.3694-1-chunkeey@googlemail.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | net: emac: Fix napi poll list corruption | expand |
From: Christian Lamparter <chunkeey@googlemail.com> Date: Tue, 19 Sep 2017 19:35:18 +0200 > This patch is pretty much a carbon copy of > commit 3079c652141f ("caif: Fix napi poll list corruption") > with "caif" replaced by "emac". > > The commit d75b1ade567f ("net: less interrupt masking in NAPI") > breaks emac. > > It is now required that if the entire budget is consumed when poll > returns, the napi poll_list must remain empty. However, like some > other drivers emac tries to do a last-ditch check and if there is > more work it will call napi_reschedule and then immediately process > some of this new work. Should the entire budget be consumed while > processing such new work then we will violate the new caller > contract. > > This patch fixes this by not touching any work when we reschedule > in emac. > > Signed-off-by: Christian Lamparter <chunkeey@googlemail.com> Applied and queued up for -stable, thanks.
diff --git a/drivers/net/ethernet/ibm/emac/mal.c b/drivers/net/ethernet/ibm/emac/mal.c index 2c74baa2398a..fff09dcf9e34 100644 --- a/drivers/net/ethernet/ibm/emac/mal.c +++ b/drivers/net/ethernet/ibm/emac/mal.c @@ -402,7 +402,7 @@ static int mal_poll(struct napi_struct *napi, int budget) unsigned long flags; MAL_DBG2(mal, "poll(%d)" NL, budget); - again: + /* Process TX skbs */ list_for_each(l, &mal->poll_list) { struct mal_commac *mc = @@ -451,7 +451,6 @@ static int mal_poll(struct napi_struct *napi, int budget) spin_lock_irqsave(&mal->lock, flags); mal_disable_eob_irq(mal); spin_unlock_irqrestore(&mal->lock, flags); - goto again; } mc->ops->poll_tx(mc->dev); }
This patch is pretty much a carbon copy of commit 3079c652141f ("caif: Fix napi poll list corruption") with "caif" replaced by "emac". The commit d75b1ade567f ("net: less interrupt masking in NAPI") breaks emac. It is now required that if the entire budget is consumed when poll returns, the napi poll_list must remain empty. However, like some other drivers emac tries to do a last-ditch check and if there is more work it will call napi_reschedule and then immediately process some of this new work. Should the entire budget be consumed while processing such new work then we will violate the new caller contract. This patch fixes this by not touching any work when we reschedule in emac. Signed-off-by: Christian Lamparter <chunkeey@googlemail.com> --- drivers/net/ethernet/ibm/emac/mal.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)