<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/net/core/skbuff.c, branch v2.6.23</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>mm: Remove slab destructors from kmem_cache_create().</title>
<updated>2007-07-20T01:11:58+00:00</updated>
<author>
<name>Paul Mundt</name>
<email>lethal@linux-sh.org</email>
</author>
<published>2007-07-20T01:11:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=20c2df83d25c6a95affe6157a4c9cac4cf5ffaac'/>
<id>20c2df83d25c6a95affe6157a4c9cac4cf5ffaac</id>
<content type='text'>
Slab destructors were no longer supported after Christoph's
c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt &lt;lethal@linux-sh.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Slab destructors were no longer supported after Christoph's
c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt &lt;lethal@linux-sh.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[NETFILTER]: x_tables: add TRACE target</title>
<updated>2007-07-11T05:17:14+00:00</updated>
<author>
<name>Jozsef Kadlecsik</name>
<email>kadlec@blackhole.kfki.hu</email>
</author>
<published>2007-07-08T05:21:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ba9dda3ab5a865542e69dfe01edb2436857c9420'/>
<id>ba9dda3ab5a865542e69dfe01edb2436857c9420</id>
<content type='text'>
The TRACE target can be used to follow IP and IPv6 packets through
the ruleset.

Signed-off-by: Jozsef Kadlecsik &lt;kadlec@blackhole.kfki.hu&gt;
Signed-off-by: Patrick NcHardy &lt;kaber@trash.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The TRACE target can be used to follow IP and IPv6 packets through
the ruleset.

Signed-off-by: Jozsef Kadlecsik &lt;kadlec@blackhole.kfki.hu&gt;
Signed-off-by: Patrick NcHardy &lt;kaber@trash.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[CORE] Stack changes to add multiqueue hardware support API</title>
<updated>2007-07-11T05:16:21+00:00</updated>
<author>
<name>Peter P Waskiewicz Jr</name>
<email>peter.p.waskiewicz.jr@intel.com</email>
</author>
<published>2007-07-06T20:36:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f25f4e44808f0f6c9875d94ef1c41ef86c288eb2'/>
<id>f25f4e44808f0f6c9875d94ef1c41ef86c288eb2</id>
<content type='text'>
Add the multiqueue hardware device support API to the core network
stack.  Allow drivers to allocate multiple queues and manage them at
the netdev level if they choose to do so.

Added a new field to sk_buff, namely queue_mapping, for drivers to
know which tx_ring to select based on OS classification of the flow.

Signed-off-by: Peter P Waskiewicz Jr &lt;peter.p.waskiewicz.jr@intel.com&gt;
Signed-off-by: Patrick McHardy &lt;kaber@trash.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add the multiqueue hardware device support API to the core network
stack.  Allow drivers to allocate multiple queues and manage them at
the netdev level if they choose to do so.

Added a new field to sk_buff, namely queue_mapping, for drivers to
know which tx_ring to select based on OS classification of the flow.

Signed-off-by: Peter P Waskiewicz Jr &lt;peter.p.waskiewicz.jr@intel.com&gt;
Signed-off-by: Patrick McHardy &lt;kaber@trash.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[SKBUFF]: Keep track of writable header len of headerless clones</title>
<updated>2007-07-11T05:15:37+00:00</updated>
<author>
<name>Patrick McHardy</name>
<email>kaber@trash.net</email>
</author>
<published>2007-06-25T11:35:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=334a8132d9950f769f390f0f35c233d099688e7a'/>
<id>334a8132d9950f769f390f0f35c233d099688e7a</id>
<content type='text'>
Currently NAT (and others) that want to modify cloned skbs copy them,
even if in the vast majority of cases its not necessary because the
skb is a clone made by TCP and the portion NAT wants to modify is
actually writable because TCP release the header reference before
cloning.

The problem is that there is no clean way for NAT to find out how
long the writable header area is, so this patch introduces skb-&gt;hdr_len
to hold this length. When a headerless skb is cloned skb-&gt;hdr_len
is set to the current headroom, for regular clones it is copied from
the original. A new function skb_clone_writable(skb, len) returns
whether the skb is writable up to len bytes from skb-&gt;data. To avoid
enlarging the skb the mac_len field is reduced to 16 bit and the
new hdr_len field is put in the remaining 16 bit.

I've done a few rough benchmarks of NAT (not with this exact patch,
but a very similar one). As expected it saves huge amounts of system
time in case of sendfile, bringing it down to basically the same
amount as without NAT, with sendmsg it only helps on loopback,
probably because of the large MTU.

Transmit a 1GB file using sendfile/sendmsg over eth0/lo with and
without NAT:

- sendfile eth0, no NAT:	sys     0m0.388s
- sendfile eth0, NAT:		sys     0m1.835s
- sendfile eth0: NAT + path:	sys     0m0.370s	(~ -80%)

- sendfile lo, no NAT:		sys     0m0.258s
- sendfile lo, NAT:		sys     0m2.609s
- sendfile lo, NAT + patch:	sys     0m0.260s	(~ -90%)

- sendmsg eth0, no NAT:		sys     0m2.508s
- sendmsg eth0, NAT:		sys     0m2.539s
- sendmsg eth0, NAT + patch:	sys     0m2.445s	(no change)

- sendmsg lo, no NAT:		sys	0m2.151s
- sendmsg lo, NAT:		sys     0m3.557s
- sendmsg lo, NAT + patch:	sys     0m2.159s	(~ -40%)

I expect other users can see a similar performance improvement,
packet mangling iptables targets, ipip and ip_gre come to mind ..

Signed-off-by: Patrick McHardy &lt;kaber@trash.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently NAT (and others) that want to modify cloned skbs copy them,
even if in the vast majority of cases its not necessary because the
skb is a clone made by TCP and the portion NAT wants to modify is
actually writable because TCP release the header reference before
cloning.

The problem is that there is no clean way for NAT to find out how
long the writable header area is, so this patch introduces skb-&gt;hdr_len
to hold this length. When a headerless skb is cloned skb-&gt;hdr_len
is set to the current headroom, for regular clones it is copied from
the original. A new function skb_clone_writable(skb, len) returns
whether the skb is writable up to len bytes from skb-&gt;data. To avoid
enlarging the skb the mac_len field is reduced to 16 bit and the
new hdr_len field is put in the remaining 16 bit.

I've done a few rough benchmarks of NAT (not with this exact patch,
but a very similar one). As expected it saves huge amounts of system
time in case of sendfile, bringing it down to basically the same
amount as without NAT, with sendmsg it only helps on loopback,
probably because of the large MTU.

Transmit a 1GB file using sendfile/sendmsg over eth0/lo with and
without NAT:

- sendfile eth0, no NAT:	sys     0m0.388s
- sendfile eth0, NAT:		sys     0m1.835s
- sendfile eth0: NAT + path:	sys     0m0.370s	(~ -80%)

- sendfile lo, no NAT:		sys     0m0.258s
- sendfile lo, NAT:		sys     0m2.609s
- sendfile lo, NAT + patch:	sys     0m0.260s	(~ -90%)

- sendmsg eth0, no NAT:		sys     0m2.508s
- sendmsg eth0, NAT:		sys     0m2.539s
- sendmsg eth0, NAT + patch:	sys     0m2.445s	(no change)

- sendmsg lo, no NAT:		sys	0m2.151s
- sendmsg lo, NAT:		sys     0m3.557s
- sendmsg lo, NAT + patch:	sys     0m2.159s	(~ -40%)

I expect other users can see a similar performance improvement,
packet mangling iptables targets, ipip and ip_gre come to mind ..

Signed-off-by: Patrick McHardy &lt;kaber@trash.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[NET] skbuff: remove export of static symbol</title>
<updated>2007-07-06T00:40:19+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes@sipsolutions.net</email>
</author>
<published>2007-07-06T00:03:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=2cd052e44329dd2b42eb958f8f346b053de6e2cd'/>
<id>2cd052e44329dd2b42eb958f8f346b053de6e2cd</id>
<content type='text'>
skb_clone_fraglist is static so it shouldn't be exported.

Signed-off-by: Johannes Berg &lt;johannes@sipsolutions.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
skb_clone_fraglist is static so it shouldn't be exported.

Signed-off-by: Johannes Berg &lt;johannes@sipsolutions.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[NET]: Make skb_seq_read unmap the last fragment</title>
<updated>2007-06-24T06:11:52+00:00</updated>
<author>
<name>Olaf Kirch</name>
<email>olaf.kirch@oracle.com</email>
</author>
<published>2007-06-24T06:11:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5b5a60da281c767196427ce8144deae6ec46b389'/>
<id>5b5a60da281c767196427ce8144deae6ec46b389</id>
<content type='text'>
Having walked through the entire skbuff, skb_seq_read would leave the
last fragment mapped.  As a consequence, the unwary caller would leak
kmaps, and proceed with preempt_count off by one. The only (kind of
non-intuitive) workaround is to use skb_seq_read_abort.

This patch makes sure skb_seq_read always unmaps frag_data after
having cycled through the skb's paged part.

Signed-off-by: Olaf Kirch &lt;olaf.kirch@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Having walked through the entire skbuff, skb_seq_read would leave the
last fragment mapped.  As a consequence, the unwary caller would leak
kmaps, and proceed with preempt_count off by one. The only (kind of
non-intuitive) workaround is to use skb_seq_read_abort.

This patch makes sure skb_seq_read always unmaps frag_data after
having cycled through the skb's paged part.

Signed-off-by: Olaf Kirch &lt;olaf.kirch@oracle.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[SKBUFF]: Fix incorrect config #ifdef around skb_copy_secmark</title>
<updated>2007-06-24T05:58:34+00:00</updated>
<author>
<name>Patrick McHardy</name>
<email>kaber@trash.net</email>
</author>
<published>2007-06-24T05:58:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=dbbeb2f9917792b989b6269ebfe24257f9aa1618'/>
<id>dbbeb2f9917792b989b6269ebfe24257f9aa1618</id>
<content type='text'>
secmark doesn't depend on CONFIG_NET_SCHED.

Signed-off-by: Patrick McHardy &lt;kaber@trash.net&gt;
Acked-by: James Morris &lt;jmorris@namei.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
secmark doesn't depend on CONFIG_NET_SCHED.

Signed-off-by: Patrick McHardy &lt;kaber@trash.net&gt;
Acked-by: James Morris &lt;jmorris@namei.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[NET]: Fix net/core/skbuff.c gcc-3.2.3 compilation error</title>
<updated>2007-05-19T20:55:25+00:00</updated>
<author>
<name>Mikael Pettersson</name>
<email>mikpe@it.uu.se</email>
</author>
<published>2007-05-19T20:55:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=b6ccc67d8e42e38936df330b26ee6d022dda8a64'/>
<id>b6ccc67d8e42e38936df330b26ee6d022dda8a64</id>
<content type='text'>
Compiling 2.6.22-rc1 with gcc-3.2.3 for i486 fails with:

  gcc -m32 -Wp,-MD,net/core/.skbuff.o.d  -nostdinc -isystem /home/mikpe/pkgs/linux-x86/gnu/lib/gcc-lib/i486-pc-linux-gnu/3.2.3/include -D__KERNEL__ -Iinclude  -include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2 -pipe -msoft-float -mregparm=3 -freg-struct-return -mpreferred-stack-boundary=4  -march=i486 -ffreestanding -maccumulate-outgoing-args -DCONFIG_AS_CFI=1  -Iinclude/asm-i386/mach-default -fomit-frame-pointer       -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(skbuff)"  -D"KBUILD_MODNAME=KBUILD_STR(skbuff)" -c -o net/core/skbuff.o net/core/skbuff.c
net/core/skbuff.c:648:1: directives may not be used inside a macro argument
net/core/skbuff.c:647:39: unterminated argument list invoking macro "memcpy"
net/core/skbuff.c: In function `pskb_expand_head':
net/core/skbuff.c:651: `memcpy' undeclared (first use in this function)
net/core/skbuff.c:651: (Each undeclared identifier is reported only once
net/core/skbuff.c:651: for each function it appears in.)
net/core/skbuff.c:651: syntax error before "skb"
make[2]: *** [net/core/skbuff.o] Error 1
make[1]: *** [net/core] Error 2
make: *** [net] Error 2

The patch below implements a simple workaround which is to
clone the offending memcpy() call and specialise it for the
two different scenarios.

Other workarounds are of course possible: e.g. bind the varying
parameter in a local variable, or use a macro or inline function
to perform the varying computation.

Signed-off-by: Mikael Pettersson &lt;mikpe@it.uu.se&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Compiling 2.6.22-rc1 with gcc-3.2.3 for i486 fails with:

  gcc -m32 -Wp,-MD,net/core/.skbuff.o.d  -nostdinc -isystem /home/mikpe/pkgs/linux-x86/gnu/lib/gcc-lib/i486-pc-linux-gnu/3.2.3/include -D__KERNEL__ -Iinclude  -include include/linux/autoconf.h -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -O2 -pipe -msoft-float -mregparm=3 -freg-struct-return -mpreferred-stack-boundary=4  -march=i486 -ffreestanding -maccumulate-outgoing-args -DCONFIG_AS_CFI=1  -Iinclude/asm-i386/mach-default -fomit-frame-pointer       -D"KBUILD_STR(s)=#s" -D"KBUILD_BASENAME=KBUILD_STR(skbuff)"  -D"KBUILD_MODNAME=KBUILD_STR(skbuff)" -c -o net/core/skbuff.o net/core/skbuff.c
net/core/skbuff.c:648:1: directives may not be used inside a macro argument
net/core/skbuff.c:647:39: unterminated argument list invoking macro "memcpy"
net/core/skbuff.c: In function `pskb_expand_head':
net/core/skbuff.c:651: `memcpy' undeclared (first use in this function)
net/core/skbuff.c:651: (Each undeclared identifier is reported only once
net/core/skbuff.c:651: for each function it appears in.)
net/core/skbuff.c:651: syntax error before "skb"
make[2]: *** [net/core/skbuff.o] Error 1
make[1]: *** [net/core] Error 2
make: *** [net] Error 2

The patch below implements a simple workaround which is to
clone the offending memcpy() call and specialise it for the
two different scenarios.

Other workarounds are of course possible: e.g. bind the varying
parameter in a local variable, or use a macro or inline function
to perform the varying computation.

Signed-off-by: Mikael Pettersson &lt;mikpe@it.uu.se&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>[NET]: Revert sk_buff walker cleanups.</title>
<updated>2007-04-27T22:21:23+00:00</updated>
<author>
<name>David S. Miller</name>
<email>davem@sunset.davemloft.net</email>
</author>
<published>2007-04-27T22:21:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1a028e50729b85d0a038fad13daf0ee201a37454'/>
<id>1a028e50729b85d0a038fad13daf0ee201a37454</id>
<content type='text'>
This reverts eefa3906283a2b60a6d02a2cda593a7d7d7946c5

The simplification made in that change works with the assumption that
the 'offset' parameter to these functions is always positive or zero,
which is not true.  It can be and often is negative in order to access
SKB header values in front of skb-&gt;data.

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts eefa3906283a2b60a6d02a2cda593a7d7d7946c5

The simplification made in that change works with the assumption that
the 'offset' parameter to these functions is always positive or zero,
which is not true.  It can be and often is negative in order to access
SKB header values in front of skb-&gt;data.

Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>[NET]: Clean up sk_buff walkers.</title>
<updated>2007-04-26T07:44:22+00:00</updated>
<author>
<name>Jean Delvare</name>
<email>jdelvare@suse.de</email>
</author>
<published>2007-04-26T07:44:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=eefa3906283a2b60a6d02a2cda593a7d7d7946c5'/>
<id>eefa3906283a2b60a6d02a2cda593a7d7d7946c5</id>
<content type='text'>
I noticed recently that, in skb_checksum(), "offset" and "start" are
essentially the same thing and have the same value throughout the
function, despite being computed differently. Using a single variable
allows some cleanups and makes the skb_checksum() function smaller,
more readable, and presumably marginally faster.

We appear to have many other "sk_buff walker" functions built on the
exact same model, so the cleanup applies to them, too. Here is a list
of the functions I found to be affected:

net/appletalk/ddp.c:atalk_sum_skb()
net/core/datagram.c:skb_copy_datagram_iovec()
net/core/datagram.c:skb_copy_and_csum_datagram()
net/core/skbuff.c:skb_copy_bits()
net/core/skbuff.c:skb_store_bits()
net/core/skbuff.c:skb_checksum()
net/core/skbuff.c:skb_copy_and_csum_bit()
net/core/user_dma.c:dma_skb_copy_datagram_iovec()
net/xfrm/xfrm_algo.c:skb_icv_walk()
net/xfrm/xfrm_algo.c:skb_to_sgvec()

OTOH, I admit I'm a bit surprised, the cleanup is rather obvious so I'm
really wondering if I am missing something. Can anyone please comment
on this?

Signed-off-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
I noticed recently that, in skb_checksum(), "offset" and "start" are
essentially the same thing and have the same value throughout the
function, despite being computed differently. Using a single variable
allows some cleanups and makes the skb_checksum() function smaller,
more readable, and presumably marginally faster.

We appear to have many other "sk_buff walker" functions built on the
exact same model, so the cleanup applies to them, too. Here is a list
of the functions I found to be affected:

net/appletalk/ddp.c:atalk_sum_skb()
net/core/datagram.c:skb_copy_datagram_iovec()
net/core/datagram.c:skb_copy_and_csum_datagram()
net/core/skbuff.c:skb_copy_bits()
net/core/skbuff.c:skb_store_bits()
net/core/skbuff.c:skb_checksum()
net/core/skbuff.c:skb_copy_and_csum_bit()
net/core/user_dma.c:dma_skb_copy_datagram_iovec()
net/xfrm/xfrm_algo.c:skb_icv_walk()
net/xfrm/xfrm_algo.c:skb_to_sgvec()

OTOH, I admit I'm a bit surprised, the cleanup is rather obvious so I'm
really wondering if I am missing something. Can anyone please comment
on this?

Signed-off-by: Jean Delvare &lt;jdelvare@suse.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
</feed>
