Commit 001ce546 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller

net: Detect drivers that reschedule NAPI and exhaust budget

The commit d75b1ade (net: less
interrupt masking in NAPI) required drivers to leave poll_list
empty if the entire budget is consumed.

We have already had two broken drivers so let's add a check for
this.
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 726ce70e
...@@ -4602,6 +4602,15 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll) ...@@ -4602,6 +4602,15 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll)
napi_gro_flush(n, HZ >= 1000); napi_gro_flush(n, HZ >= 1000);
} }
/* Some drivers may have called napi_schedule
* prior to exhausting their budget.
*/
if (unlikely(!list_empty(&n->poll_list))) {
pr_warn_once("%s: Budget exhausted after napi rescheduled\n",
n->dev ? n->dev->name : "backlog");
goto out_unlock;
}
list_add_tail(&n->poll_list, repoll); list_add_tail(&n->poll_list, repoll);
out_unlock: out_unlock:
......
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