With this we save 8 bytes per network packet, leaving a 4 bytes hole to be used
in further shrinking work, likely with the offsetization of other pointers,
such as ->{data,tail,end}, at the cost of adds, that were minimized by the
usual practice of setting skb->{mac,nh,n}.raw to a local variable that is then
accessed multiple times in each function, it also is not more expensive than
before with regards to most of the handling of such headers, like setting one
of these headers to another (transport to network, etc), or subtracting, adding
to/from it, comparing them, etc.

Now we have this layout for sk_buff on a x86_64 machine:

[acme@mica net-2.6.22]$ pahole vmlinux sk_buff
struct sk_buff {
	struct sk_buff *       next;             /*   0   8 */
	struct sk_buff *       prev;             /*   8   8 */
	struct rb_node         rb;               /*  16  24 */
	struct sock *          sk;               /*  40   8 */
	ktime_t                tstamp;           /*  48   8 */
	struct net_device *    dev;              /*  56   8 */
	/* --- cacheline 1 boundary (64 bytes) --- */
	struct net_device *    input_dev;        /*  64   8 */
	sk_buff_data_t         transport_header; /*  72   4 */
	sk_buff_data_t         network_header;   /*  76   4 */
	sk_buff_data_t         mac_header;       /*  80   4 */

	/* XXX 4 bytes hole, try to pack */

	struct dst_entry *     dst;              /*  88   8 */
	struct sec_path *      sp;               /*  96   8 */
	char                   cb[48];           /* 104  48 */
	/* cacheline 2 boundary (128 bytes) was 24 bytes ago*/
	unsigned int           len;              /* 152   4 */
	unsigned int           data_len;         /* 156   4 */
	unsigned int           mac_len;          /* 160   4 */
	union {
		__wsum         csum;             /*       4 */
		__u32          csum_offset;      /*       4 */
	};                                       /* 164   4 */
	__u32                  priority;         /* 168   4 */
	__u8                   local_df:1;       /* 172   1 */
	__u8                   cloned:1;         /* 172   1 */
	__u8                   ip_summed:2;      /* 172   1 */
	__u8                   nohdr:1;          /* 172   1 */
	__u8                   nfctinfo:3;       /* 172   1 */
	__u8                   pkt_type:3;       /* 173   1 */
	__u8                   fclone:2;         /* 173   1 */
	__u8                   ipvs_property:1;  /* 173   1 */

	/* XXX 2 bits hole, try to pack */

	__be16                 protocol;         /* 174   2 */
	void    (*destructor)(struct sk_buff *); /* 176   8 */
	struct nf_conntrack *  nfct;             /* 184   8 */
	/* --- cacheline 3 boundary (192 bytes) --- */
	struct sk_buff *       nfct_reasm;       /* 192   8 */
	struct nf_bridge_info *nf_bridge;        /* 200   8 */
	__u16                  tc_index;         /* 208   2 */
	__u16                  tc_verd;          /* 210   2 */
	dma_cookie_t           dma_cookie;       /* 212   4 */
	__u32                  secmark;          /* 216   4 */
	__u32                  mark;             /* 220   4 */
	unsigned int           truesize;         /* 224   4 */
	atomic_t               users;            /* 228   4 */
	unsigned char *        head;             /* 232   8 */
	unsigned char *        data;             /* 240   8 */
	unsigned char *        tail;             /* 248   8 */
	/* --- cacheline 4 boundary (256 bytes) --- */
	unsigned char *        end;              /* 256   8 */
}; /* size: 264, cachelines: 5 */
   /* sum members: 260, holes: 1, sum holes: 4 */
   /* bit holes: 1, sum bit holes: 2 bits */
   /* last cacheline: 8 bytes */

On 32 bits nothing changes, and pointers continue to be used with the compiler
turning all this abstraction layer into dust. But there are some sk_buff
validation tricks that are now possible, humm... :-)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Renaming skb->h to skb->transport_header, skb->nh to skb->network_header and
skb->mac to skb->mac_header, to match the names of the associated helpers
(skb[_[re]set]_{transport,network,mac}_header).
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For the common sequence "skb->h.raw - skb->nh.raw", similar to skb->mac_len,
that is precalculated tho, don't think we need to bloat skb with one more
member, so just use this new helper, reducing the number of non-skbuff.h
references to the layer headers even more.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This unifies the codes to copy netfilter related datas. Note that
__nf_copy() assumes destination skb doesn't have any netfilter
related members.
Signed-off-by: NYasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For the quite common 'skb->h.raw - skb->data' sequence.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For the places where we need a pointer to the mac header, it is still legal to
touch skb->mac.raw directly if just adding to, subtracting from or setting it
to another layer header.

This one also converts some more cases to skb_reset_mac_header() that my
regex missed as it had no spaces before nor after '=', ugh.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For the common, open coded 'skb->mac.raw = skb->data' operation, so that we can
later turn skb->mac.raw into a offset, reducing the size of struct sk_buff in
64bit land while possibly keeping it as a pointer on 32bit.

This one touches just the most simple case, next will handle the slightly more
"complex" cases.
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since this was added originally for Xen, and Xen has recently (~2.6.18)
stopped using this function, we can safely get rid of it.  Good timing
too since this function has started to bit rot.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The input_device pointer is not refcounted, which means the device may
disappear while packets are queued, causing a crash when ifb passes packets
with a stale skb->dev pointer to netif_rx().

Fix by storing the interface index instead and do a lookup where neccessary.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Acked-by: NJamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

ANK says: "It is rarely used, that's wy it was not noticed.
But in the places, where it is used, it should be disaster."
Signed-off-by: NAlexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NPatrick McHardy <kaber@trash.net>
Acked-by: NPaul Moore <paul.moore@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there.  Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.

To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.

Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm.  I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).
Signed-off-by: NTim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This lets the network core have the ability to handle suspend/resume
issues, if it wants to.

Thanks to Frederik Deweerdt <frederik.deweerdt@gmail.com> for the arm
driver fixes.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Replace all uses of kmem_cache_t with struct kmem_cache.

The patch was generated using the following script:

	#!/bin/sh
	#
	# Replace one string by another in all the kernel sources.
	#

	set -e

	for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
		quilt add $file
		sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
		mv /tmp/$$ $file
		quilt refresh
	done

The script was run like this

	sh replace kmem_cache_t "struct kmem_cache"
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Node-aware allocation of skbs for the receive path.

Details:

  - __alloc_skb gets a new node argument and cals the node-aware
    slab functions with it.
  - netdev_alloc_skb passed the node number it gets from dev_to_node
    to it, everyone else passes -1 (any node)
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... into anonymous union of __wsum and __u32 (csum and csum_offset resp.)
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

nfmark is being used in various subsystems and has become
the defacto mark field for all kinds of packets. Therefore
it makes sense to rename it to `mark' and remove the
dependency on CONFIG_NETFILTER.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since pskb_copy tacks on the non-linear bits from the original
skb, it needs to count them in the truesize field of the new skb.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

skb_segment fails to segment linear packets correctly because it
tries to write all linear parts of the original skb into each
segment.  This will always panic as each segment only contains
enough space for one MSS.

This was not detected earlier because linear packets should be
rare for GSO.  In fact it still remains to be seen what exactly
created the linear packets that triggered this bug.  Basically
the only time this should happen is if someone enables GSO
emulation on an interface that does not support SG.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

- rename ____kmalloc to kmalloc_track_caller so that people have a chance
  to guess what it does just from it's name.  Add a comment describing it
  for those who don't.  Also move it after kmalloc in slab.h so people get
  less confused when they are just looking for kmalloc - move things around
  in slab.c a little to reduce the ifdef mess.

[penberg@cs.helsinki.fi: Fix up reversed #ifdef]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace CHECKSUM_HW by CHECKSUM_PARTIAL (for outgoing packets, whose
checksum still needs to be completed) and CHECKSUM_COMPLETE (for
incoming packets, device supplied full checksum).

Patch originally from Herbert Xu, updated by myself for 2.6.18-rc3.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Acked-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a dev_alloc_skb variant that takes a struct net_device * paramater.
For now that paramater is unused, but I'll use it to allocate the skb
from node-local memory in a follow-up patch.  Also there have been some
other plans mentioned on the list that can use it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When the trim point is within the head and there is no paged data,
___pskb_trim fails to drop the first element in the frag_list.
This patch fixes this by moving the len <= offset case out of the
page data loop.

This patch also adds a missing kfree_skb on the frag that we just
cloned.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When pskb_trim has to defer to ___pksb_trim to trim the frag_list part of
the packet, the frag_list is not updated to reflect the trimming.  This
will usually work fine until you hit something that uses the packet length
or tail from the frag_list.

Examples include esp_output and ip_fragment.

Another problem caused by this is that you can end up with a linear packet
with a frag_list attached.

It is possible to get away with this if we audit everything to make sure
that they always consult skb->len before going down onto frag_list.  In
fact we can do the samething for the paged part as well to avoid copying
the data area of the skb.  For now though, let's do the conservative fix
and update frag_list.

Many thanks to Marco Berizzi for helping me to track down this bug.

This 4-year old bug took 3 months to track down.  Marco was very patient
indeed :)
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Teach special (multi-initialized) locking code to the lock validator.  Has no
effect on non-lockdep kernels.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

skb_release_data() no longer has any users in other files.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When GSO packets come from an untrusted source (e.g., a Xen guest domain),
we need to verify the header integrity before passing it to the hardware.

Since the first step in GSO is to verify the header, we can reuse that
code by adding a new bit to gso_type: SKB_GSO_DODGY.  Packets with this
bit set can only be fed directly to devices with the corresponding bit
NETIF_F_GSO_ROBUST.  If the device doesn't have that bit, then the skb
is fed to the GSO engine which will allow the packet to be sent to the
hardware if it passes the header check.

This patch changes the sg flag to a full features flag.  The same method
can be used to implement TSO ECN support.  We simply have to mark packets
with CWR set with SKB_GSO_ECN so that only hardware with a corresponding
NETIF_F_TSO_ECN can accept them.  The GSO engine can either fully segment
the packet, or segment the first MTU and pass the rest to the hardware for
further segmentation.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>