From d9452e9f81e997cbd0c9bface8d2c2a4b064cc3e Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 4 Mar 2008 12:28:49 -0800 Subject: [PATCH] [NETPOLL]: Revert two bogus cleanups that broke netconsole. Based upon a report by Andrew Morton and code analysis done by Jarek Poplawski. This reverts 33f807ba0d9259e7c75c7a2ce8bd2787e5b540c7 ("[NETPOLL]: Kill NETPOLL_RX_DROP, set but never tested.") and c7b6ea24b43afb5749cb704e143df19d70e23dea ("[NETPOLL]: Don't need rx_flags."). The rx_flags did get tested for zero vs. non-zero and therefore we do need those tests and that code which sets NETPOLL_RX_DROP et al. Signed-off-by: David S. Miller --- include/linux/netpoll.h | 7 ++++--- net/core/netpoll.c | 12 ++++++++---- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index a0525a1f4715..e3d79593fb3a 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -25,6 +25,7 @@ struct netpoll { struct netpoll_info { atomic_t refcnt; + int rx_flags; spinlock_t rx_lock; struct netpoll *rx_np; /* netpoll that registered an rx_hook */ struct sk_buff_head arp_tx; /* list of arp requests to reply to */ @@ -50,12 +51,12 @@ static inline int netpoll_rx(struct sk_buff *skb) unsigned long flags; int ret = 0; - if (!npinfo || !npinfo->rx_np) + if (!npinfo || (!npinfo->rx_np && !npinfo->rx_flags)) return 0; spin_lock_irqsave(&npinfo->rx_lock, flags); - /* check rx_np again with the lock held */ - if (npinfo->rx_np && __netpoll_rx(skb)) + /* check rx_flags again with the lock held */ + if (npinfo->rx_flags && __netpoll_rx(skb)) ret = 1; spin_unlock_irqrestore(&npinfo->rx_lock, flags); diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 6faa128a4c8e..4b7e756181c9 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -39,6 +39,8 @@ static struct sk_buff_head skb_pool; static atomic_t trapped; #define USEC_PER_POLL 50 +#define NETPOLL_RX_ENABLED 1 +#define NETPOLL_RX_DROP 2 #define MAX_SKB_SIZE \ (MAX_UDP_CHUNK + sizeof(struct udphdr) + \ @@ -126,11 +128,13 @@ static int poll_one_napi(struct netpoll_info *npinfo, if (!test_bit(NAPI_STATE_SCHED, &napi->state)) return budget; + npinfo->rx_flags |= NETPOLL_RX_DROP; atomic_inc(&trapped); work = napi->poll(napi, budget); atomic_dec(&trapped); + npinfo->rx_flags &= ~NETPOLL_RX_DROP; return budget - work; } @@ -472,7 +476,7 @@ int __netpoll_rx(struct sk_buff *skb) if (skb->dev->type != ARPHRD_ETHER) goto out; - /* if receive ARP during middle of NAPI poll, then queue */ + /* check if netpoll clients need ARP */ if (skb->protocol == htons(ETH_P_ARP) && atomic_read(&trapped)) { skb_queue_tail(&npi->arp_tx, skb); @@ -534,9 +538,6 @@ int __netpoll_rx(struct sk_buff *skb) return 1; out: - /* If packet received while already in poll then just - * silently drop. - */ if (atomic_read(&trapped)) { kfree_skb(skb); return 1; @@ -675,6 +676,7 @@ int netpoll_setup(struct netpoll *np) goto release; } + npinfo->rx_flags = 0; npinfo->rx_np = NULL; spin_lock_init(&npinfo->rx_lock); @@ -756,6 +758,7 @@ int netpoll_setup(struct netpoll *np) if (np->rx_hook) { spin_lock_irqsave(&npinfo->rx_lock, flags); + npinfo->rx_flags |= NETPOLL_RX_ENABLED; npinfo->rx_np = np; spin_unlock_irqrestore(&npinfo->rx_lock, flags); } @@ -797,6 +800,7 @@ void netpoll_cleanup(struct netpoll *np) if (npinfo->rx_np == np) { spin_lock_irqsave(&npinfo->rx_lock, flags); npinfo->rx_np = NULL; + npinfo->rx_flags &= ~NETPOLL_RX_ENABLED; spin_unlock_irqrestore(&npinfo->rx_lock, flags); }