From 001ce546bb537bb5b7821f05633556a0c9787e32 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 21 Dec 2014 07:16:22 +1100 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/core/dev.c | 9 +++++++++ 1 file changed, 9 insertions(+) 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: -- GitLab