net: Detect drivers that reschedule NAPI and exhaust budget
The commit d75b1ade567ffab085e8adbbdacf0092d10cd09c (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: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 493ae8e..c0cf129 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4602,6 +4602,15 @@
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);
out_unlock: