From d1a203eac0ec13cd1c0ba610fe7a55c9bc40473b Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Sat, 1 Nov 2008 21:01:09 -0700 Subject: net: add documentation for skb recycling Commit 04a4bb55bcf35b63d40fd2725e58599ff8310dd7 ("net: add skb_recycle_check() to enable netdriver skb recycling") added a method for network drivers to recycle skbuffs, but while use of this mechanism was documented in the commit message, it should really have been added as a docbook comment as well -- this patch does that. Signed-off-by: Stephen Hemminger Signed-off-by: Lennert Buytenhek Signed-off-by: David S. Miller --- net/core/skbuff.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'net/core') diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 4e22e3a3535..ebb6b94f8af 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -449,6 +449,18 @@ void kfree_skb(struct sk_buff *skb) __kfree_skb(skb); } +/** + * skb_recycle_check - check if skb can be reused for receive + * @skb: buffer + * @skb_size: minimum receive buffer size + * + * Checks that the skb passed in is not shared or cloned, and + * that it is linear and its head portion at least as large as + * skb_size so that it can be recycled as a receive buffer. + * If these conditions are met, this function does any necessary + * reference count dropping and cleans up the skbuff as if it + * just came from __alloc_skb(). + */ int skb_recycle_check(struct sk_buff *skb, int skb_size) { struct skb_shared_info *shinfo; -- cgit v1.2.3 From 9b22ea560957de1484e6b3e8538f7eef202e3596 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Tue, 4 Nov 2008 14:49:57 -0800 Subject: net: fix packet socket delivery in rx irq handler The changes to deliver hardware accelerated VLAN packets to packet sockets (commit bc1d0411) caused a warning for non-NAPI drivers. The __vlan_hwaccel_rx() function is called directly from the drivers RX function, for non-NAPI drivers that means its still in RX IRQ context: [ 27.779463] ------------[ cut here ]------------ [ 27.779509] WARNING: at kernel/softirq.c:136 local_bh_enable+0x37/0x81() ... [ 27.782520] [] netif_nit_deliver+0x5b/0x75 [ 27.782590] [] __vlan_hwaccel_rx+0x79/0x162 [ 27.782664] [] atl1_intr+0x9a9/0xa7c [atl1] [ 27.782738] [] handle_IRQ_event+0x23/0x51 [ 27.782808] [] handle_edge_irq+0xc2/0x102 [ 27.782878] [] do_IRQ+0x4d/0x64 Split hardware accelerated VLAN reception into two parts to fix this: - __vlan_hwaccel_rx just stores the VLAN TCI and performs the VLAN device lookup, then calls netif_receive_skb()/netif_rx() - vlan_hwaccel_do_receive(), which is invoked by netif_receive_skb() in softirq context, performs the real reception and delivery to packet sockets. Reported-and-tested-by: Ramon Casellas Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/core/dev.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/core') diff --git a/net/core/dev.c b/net/core/dev.c index d9038e328cc..9174c77d311 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2218,6 +2218,9 @@ int netif_receive_skb(struct sk_buff *skb) int ret = NET_RX_DROP; __be16 type; + if (skb->vlan_tci && vlan_hwaccel_do_receive(skb)) + return NET_RX_SUCCESS; + /* if we've gotten here through NAPI, check netpoll */ if (netpoll_receive_skb(skb)) return NET_RX_DROP; -- cgit v1.2.3 From 3b53fbf4314594fa04544b02b2fc6e607912da18 Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Thu, 6 Nov 2008 15:45:32 -0800 Subject: net: Fix recursive descent in __scm_destroy(). __scm_destroy() walks the list of file descriptors in the scm_fp_list pointed to by the scm_cookie argument. Those, in turn, can close sockets and invoke __scm_destroy() again. There is nothing which limits how deeply this can occur. The idea for how to fix this is from Linus. Basically, we do all of the fput()s at the top level by collecting all of the scm_fp_list objects hit by an fput(). Inside of the initial __scm_destroy() we keep running the list until it is empty. Signed-off-by: David S. Miller --- net/core/scm.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) (limited to 'net/core') diff --git a/net/core/scm.c b/net/core/scm.c index 10f5c65f6a4..ab242cc1acc 100644 --- a/net/core/scm.c +++ b/net/core/scm.c @@ -75,6 +75,7 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp) if (!fpl) return -ENOMEM; *fplp = fpl; + INIT_LIST_HEAD(&fpl->list); fpl->count = 0; } fpp = &fpl->fp[fpl->count]; @@ -106,9 +107,25 @@ void __scm_destroy(struct scm_cookie *scm) if (fpl) { scm->fp = NULL; - for (i=fpl->count-1; i>=0; i--) - fput(fpl->fp[i]); - kfree(fpl); + if (current->scm_work_list) { + list_add_tail(&fpl->list, current->scm_work_list); + } else { + LIST_HEAD(work_list); + + current->scm_work_list = &work_list; + + list_add(&fpl->list, &work_list); + while (!list_empty(&work_list)) { + fpl = list_first_entry(&work_list, struct scm_fp_list, list); + + list_del(&fpl->list); + for (i=fpl->count-1; i>=0; i--) + fput(fpl->fp[i]); + kfree(fpl); + } + + current->scm_work_list = NULL; + } } } @@ -284,6 +301,7 @@ struct scm_fp_list *scm_fp_dup(struct scm_fp_list *fpl) new_fpl = kmalloc(sizeof(*fpl), GFP_KERNEL); if (new_fpl) { + INIT_LIST_HEAD(&new_fpl->list); for (i=fpl->count-1; i>=0; i--) get_file(fpl->fp[i]); memcpy(new_fpl, fpl, sizeof(*fpl)); -- cgit v1.2.3