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authorHerbert Xu <herbert@gondor.apana.org.au>2014-12-21 07:16:22 +1100
committerDavid S. Miller <davem@davemloft.net>2014-12-23 23:20:21 -0500
commit001ce546bb537bb5b7821f05633556a0c9787e32 (patch)
tree3e3fde752c8c4bd05e6c3cb57318069e6e54bbd7
parent726ce70e9e4050409243f3a1d735dc86bc6e6e57 (diff)
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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>
-rw-r--r--net/core/dev.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 493ae8ee569f..c0cf1293df06 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4602,6 +4602,15 @@ static int napi_poll(struct napi_struct *n, struct list_head *repoll)
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: