user/sven/linux.git/include/linux/skbuff.h, branch v3.3.5

tcp: avoid order-1 allocations on wifi and tx path

2012-04-27T17:17:06Z

[ This combines upstream commit a21d45726acacc963d8baddf74607d9b74e2b723 and the follow-on bug fix commit a21d45726acacc963d8baddf74607d9b74e2b723 ] Marc Merlin reported many order-1 allocations failures in TX path on its wireless setup, that dont make any sense with MTU=1500 network, and non SG capable hardware. After investigation, it turns out TCP uses sk_stream_alloc_skb() and used as a convention skb_tailroom(skb) to know how many bytes of data payload could be put in this skb (for non SG capable devices) Note : these skb used kmalloc-4096 (MTU=1500 + MAX_HEADER + sizeof(struct skb_shared_info) being above 2048) Later, mac80211 layer need to add some bytes at the tail of skb (IEEE80211_ENCRYPT_TAILROOM = 18 bytes) and since no more tailroom is available has to call pskb_expand_head() and request order-1 allocations. This patch changes sk_stream_alloc_skb() so that only sk->sk_prot->max_header bytes of headroom are reserved, and use a new skb field, avail_size to hold the data payload limit. This way, order-0 allocations done by TCP stack can leave more than 2 KB of tailroom and no more allocation is performed in mac80211 layer (or any layer needing some tailroom) avail_size is unioned with mark/dropcount, since mark will be set later in IP stack for output packets. Therefore, skb size is unchanged. Reported-by: Marc MERLIN Tested-by: Marc MERLIN Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

ipsec: be careful of non existing mac headers

2012-02-23T21:50:45Z

Niccolo Belli reported ipsec crashes in case we handle a frame without mac header (atm in his case) Before copying mac header, better make sure it is present. Bugzilla reference: https://bugzilla.kernel.org/show_bug.cgi?id=42809 Reported-by: Niccolò Belli Tested-by: Niccolò Belli Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: pack skb_shared_info more efficiently

2012-01-05T19:01:21Z

nr_frags can be 8 bits since 256 is plenty of fragments. This allows it to be packed with tx_flags. Also by moving ip6_frag_id and dataref (both 4 bytes) next to each other we can avoid a hole between ip6_frag_id and frag_list on 64 bit systems. Signed-off-by: Ian Campbell Acked-by: Eric Dumazet Signed-off-by: David S. Miller

net: only use a single page of slop in MAX_SKB_FRAGS

2011-12-23T21:51:18Z

In order to accommodate a 64K buffer we need 64K/PAGE_SIZE plus one more page in order to allow for a buffer which does not start on a page boundary. Signed-off-by: Ian Campbell Signed-off-by: David S. Miller

tcp: take care of misalignments

2011-12-04T18:20:39Z

We discovered that TCP stack could retransmit misaligned skbs if a malicious peer acknowledged sub MSS frame. This currently can happen only if output interface is non SG enabled : If SG is enabled, tcp builds headless skbs (all payload is included in fragments), so the tcp trimming process only removes parts of skb fragments, header stay aligned. Some arches cant handle misalignments, so force a head reallocation and shrink headroom to MAX_TCP_HEADER. Dont care about misaligments on x86 and PPC (or other arches setting NET_IP_ALIGN to 0) This patch introduces __pskb_copy() which can specify the headroom of new head, and pskb_copy() becomes a wrapper on top of __pskb_copy() Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: remove netdev_alloc_page and use __GFP_COLD

2011-11-22T21:43:32Z

Given we dont use anymore the struct net_device *dev argument, and this interface brings litle benefit, remove netdev_{alloc|free}_page(), to debloat include/linux/skbuff.h a bit. (Some drivers used a mix of these interfaces and alloc_pages()) When allocating a page given to device for DMA transfer (device to memory), it makes sense to use a cold one (__GFP_COLD) Signed-off-by: Eric Dumazet CC: Jeff Kirsher CC: Dimitris Michailidis Signed-off-by: David S. Miller

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next into for-davem

2011-11-17T18:11:43Z

Conflicts: include/net/bluetooth/bluetooth.h

net: remove NETIF_F_NO_CSUM feature bit

2011-11-16T22:43:12Z

Only distinct use is checking if NETIF_F_NOCACHE_COPY should be enabled by default. The check heuristics is altered a bit here, so it hits other people than before. The default shouldn't be trusted for performance-critical cases anyway. For all other uses NETIF_F_NO_CSUM is equivalent to NETIF_F_HW_CSUM. Signed-off-by: Michał Mirosław Signed-off-by: David S. Miller

net: introduce and use netdev_features_t for device features sets

2011-11-16T22:43:10Z

v2: add couple missing conversions in drivers split unexporting netdev_fix_features() implemented %pNF convert sock::sk_route_(no?)caps Signed-off-by: Michał Mirosław Signed-off-by: David S. Miller

net: introduce build_skb()

2011-11-14T19:13:30Z

One of the thing we discussed during netdev 2011 conference was the idea to change some network drivers to allocate/populate their skb at RX completion time, right before feeding the skb to network stack. In old days, we allocated skbs when populating the RX ring. This means bringing into cpu cache sk_buff and skb_shared_info cache lines (since we clear/initialize them), then 'queue' skb->data to NIC. By the time NIC fills a frame in skb->data buffer and host can process it, cpu probably threw away the cache lines from its caches, because lot of things happened between the allocation and final use. So the deal would be to allocate only the data buffer for the NIC to populate its RX ring buffer. And use build_skb() at RX completion to attach a data buffer (now filled with an ethernet frame) to a new skb, initialize the skb_shared_info portion, and give the hot skb to network stack. build_skb() is the function to allocate an skb, caller providing the data buffer that should be attached to it. Drivers are expected to call skb_reserve() right after build_skb() to adjust skb->data to the Ethernet frame (usually skipping NET_SKB_PAD and NET_IP_ALIGN, but some drivers might add a hardware provided alignment) Data provided to build_skb() MUST have been allocated by a prior kmalloc() call, with enough room to add SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) bytes at the end of the data without corrupting incoming frame. data = kmalloc(NET_SKB_PAD + NET_IP_ALIGN + 1536 + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)), GFP_ATOMIC); ... skb = build_skb(data); if (!skb) { recycle_data(data); } else { skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN); ... } Signed-off-by: Eric Dumazet CC: Eilon Greenstein CC: Ben Hutchings CC: Tom Herbert CC: Jamal Hadi Salim CC: Stephen Hemminger CC: Thomas Graf CC: Herbert Xu CC: Jeff Kirsher Signed-off-by: David S. Miller