net: remove skb_free_datagram_locked()

Last user of skb_free_datagram_locked() went away in 2016
with commit 850cbaddb52d ("udp: use it's own memory
accounting schema").

Signed-off-by: Eric Dumazet

net: remove skb_free_datagram_locked()

Last user of skb_free_datagram_locked() went away in 2016
with commit 850cbaddb52d ("udp: use it's own memory
accounting schema").

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240325134155.620531-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

show more ...

net: Fix from address in memcpy_to_iter_csum()

While inlining csum_and_memcpy() into memcpy_to_iter_csum(), the from
address passed to csum_partial_copy_nocheck() was accidentally changed.
This caus

net: Fix from address in memcpy_to_iter_csum()

While inlining csum_and_memcpy() into memcpy_to_iter_csum(), the from
address passed to csum_partial_copy_nocheck() was accidentally changed.
This causes a regression in applications using UDP, as for example
OpenAFS, causing loss of datagrams.

Fixes: dc32bff195b4 ("iov_iter, net: Fold in csum_and_memcpy()")
Cc: David Howells <dhowells@redhat.com>
Cc: stable@vger.kernel.org
Cc: regressions@lists.linux.dev
Signed-off-by: Michael Lass <bevan@bi-co.net>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

iov_iter, net: Move hash_and_copy_to_iter() to net/

Move hash_and_copy_to_iter() to be with its only caller in networking code.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore

iov_iter, net: Move hash_and_copy_to_iter() to net/

Move hash_and_copy_to_iter() to be with its only caller in networking code.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230925120309.1731676-13-dhowells@redhat.com
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Christian Brauner <christian@brauner.io>
cc: Matthew Wilcox <willy@infradead.org>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: David Laight <David.Laight@ACULAB.COM>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
cc: netdev@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

show more ...

iov_iter, net: Merge csum_and_copy_from_iter{,_full}() together

Move csum_and_copy_from_iter_full() out of line and then merge
csum_and_copy_from_iter() into its only caller.

Signed-off-by: David H

iov_iter, net: Merge csum_and_copy_from_iter{,_full}() together

Move csum_and_copy_from_iter_full() out of line and then merge
csum_and_copy_from_iter() into its only caller.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230925120309.1731676-12-dhowells@redhat.com
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Christian Brauner <christian@brauner.io>
cc: Matthew Wilcox <willy@infradead.org>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: David Laight <David.Laight@ACULAB.COM>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
cc: netdev@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

show more ...

iov_iter, net: Fold in csum_and_memcpy()

Fold csum_and_memcpy() in to its callers.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230925120309.1731676-11-dhowe

iov_iter, net: Fold in csum_and_memcpy()

Fold csum_and_memcpy() in to its callers.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230925120309.1731676-11-dhowells@redhat.com
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Christian Brauner <christian@brauner.io>
cc: Matthew Wilcox <willy@infradead.org>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: David Laight <David.Laight@ACULAB.COM>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
cc: netdev@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

show more ...

iov_iter, net: Move csum_and_copy_to/from_iter() to net/

Move csum_and_copy_to/from_iter() to net code now that the iteration
framework can be #included.

Signed-off-by: David Howells <dhowells@redh

iov_iter, net: Move csum_and_copy_to/from_iter() to net/

Move csum_and_copy_to/from_iter() to net code now that the iteration
framework can be #included.

Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230925120309.1731676-10-dhowells@redhat.com
cc: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Christian Brauner <christian@brauner.io>
cc: Matthew Wilcox <willy@infradead.org>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: David Laight <David.Laight@ACULAB.COM>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
cc: netdev@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

show more ...

net: datagram: fix data-races in datagram_poll()

datagram_poll() runs locklessly, we should add READ_ONCE()
annotations while reading sk->sk_err, sk->sk_shutdown and sk->sk_state.

Fixes: 1da177e4c3

net: datagram: fix data-races in datagram_poll()

datagram_poll() runs locklessly, we should add READ_ONCE()
annotations while reading sk->sk_err, sk->sk_shutdown and sk->sk_state.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230509173131.3263780-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net-zerocopy: Reduce compound page head access

When compound pages are enabled, although the mm layer still
returns an array of page pointers, a subset (or all) of them
may have the same page head s

net-zerocopy: Reduce compound page head access

When compound pages are enabled, although the mm layer still
returns an array of page pointers, a subset (or all) of them
may have the same page head since a max 180kb skb can span 2
hugepages if it is on the boundary, be a mix of pages and 1 hugepage,
or fit completely in a hugepage. Instead of referencing page head
on all page pointers, use page length arithmetic to only call page
head when referencing a known different page head to avoid touching
a cold cacheline.

Tested:
See next patch with changes to tcp_mmap

Correntess:
On a pair of separate hosts as send with MSG_ZEROCOPY will
force a copy on tx if using loopback alone, check that the SHA
on the message sent is equivalent to checksum on the message received,
since the current program already checks for the length.

echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
./tcp_mmap -s -z
./tcp_mmap -H $DADDR -z

SHA256 is correct
received 2 MB (100 % mmap'ed) in 0.005914 s, 2.83686 Gbit
cpu usage user:0.001984 sys:0.000963, 1473.5 usec per MB, 10 c-switches

Performance:
Run neper between adjacent hosts with the same config
tcp_stream -Z --skip-rx-copy -6 -T 20 -F 1000 --stime-use-proc --test-length=30

Before patch: stime_end=37.670000
After patch: stime_end=30.310000

Signed-off-by: Coco Li <lixiaoyan@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230321081202.2370275-1-lixiaoyan@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

show more ...

tcp: TX zerocopy should not sense pfmemalloc status

We got a recent syzbot report [1] showing a possible misuse
of pfmemalloc page status in TCP zerocopy paths.

Indeed, for pages coming from user s

tcp: TX zerocopy should not sense pfmemalloc status

We got a recent syzbot report [1] showing a possible misuse
of pfmemalloc page status in TCP zerocopy paths.

Indeed, for pages coming from user space or other layers,
using page_is_pfmemalloc() is moot, and possibly could give
false positives.

There has been attempts to make page_is_pfmemalloc() more robust,
but not using it in the first place in this context is probably better,
removing cpu cycles.

Note to stable teams :

You need to backport 84ce071e38a6 ("net: introduce
__skb_fill_page_desc_noacc") as a prereq.

Race is more probable after commit c07aea3ef4d4
("mm: add a signature in struct page") because page_is_pfmemalloc()
is now using low order bit from page->lru.next, which can change
more often than page->index.

Low order bit should never be set for lru.next (when used as an anchor
in LRU list), so KCSAN report is mostly a false positive.

Backporting to older kernel versions seems not necessary.

[1]
BUG: KCSAN: data-race in lru_add_fn / tcp_build_frag

write to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0:
__list_add include/linux/list.h:73 [inline]
list_add include/linux/list.h:88 [inline]
lruvec_add_folio include/linux/mm_inline.h:105 [inline]
lru_add_fn+0x440/0x520 mm/swap.c:228
folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246
folio_batch_add_and_move mm/swap.c:263 [inline]
folio_add_lru+0xf1/0x140 mm/swap.c:490
filemap_add_folio+0xf8/0x150 mm/filemap.c:948
__filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981
pagecache_get_page+0x26/0x190 mm/folio-compat.c:104
grab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116
ext4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988
generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3738
ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270
ext4_file_write_iter+0x2e3/0x1210
call_write_iter include/linux/fs.h:2187 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x468/0x760 fs/read_write.c:578
ksys_write+0xe8/0x1a0 fs/read_write.c:631
__do_sys_write fs/read_write.c:643 [inline]
__se_sys_write fs/read_write.c:640 [inline]
__x64_sys_write+0x3e/0x50 fs/read_write.c:640
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffea0004a1d2c8 of 8 bytes by task 18611 on cpu 1:
page_is_pfmemalloc include/linux/mm.h:1740 [inline]
__skb_fill_page_desc include/linux/skbuff.h:2422 [inline]
skb_fill_page_desc include/linux/skbuff.h:2443 [inline]
tcp_build_frag+0x613/0xb20 net/ipv4/tcp.c:1018
do_tcp_sendpages+0x3e8/0xaf0 net/ipv4/tcp.c:1075
tcp_sendpage_locked net/ipv4/tcp.c:1140 [inline]
tcp_sendpage+0x89/0xb0 net/ipv4/tcp.c:1150
inet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833
kernel_sendpage+0x184/0x300 net/socket.c:3561
sock_sendpage+0x5a/0x70 net/socket.c:1054
pipe_to_sendpage+0x128/0x160 fs/splice.c:361
splice_from_pipe_feed fs/splice.c:415 [inline]
__splice_from_pipe+0x222/0x4d0 fs/splice.c:559
splice_from_pipe fs/splice.c:594 [inline]
generic_splice_sendpage+0x89/0xc0 fs/splice.c:743
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:931
splice_direct_to_actor+0x305/0x620 fs/splice.c:886
do_splice_direct+0xfb/0x180 fs/splice.c:974
do_sendfile+0x3bf/0x910 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64 fs/read_write.c:1303 [inline]
__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -> 0xffffea0004a1d288

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18611 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00248-ge022620b5d05-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022

Fixes: c07aea3ef4d4 ("mm: add a signature in struct page")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

iov_iter: advancing variants of iov_iter_get_pages{,_alloc}()

Most of the users immediately follow successful iov_iter_get_pages()
with advancing by the amount it had returned.

Provide inline wrapp

iov_iter: advancing variants of iov_iter_get_pages{,_alloc}()

Most of the users immediately follow successful iov_iter_get_pages()
with advancing by the amount it had returned.

Provide inline wrappers doing that, convert trivial open-coded
uses of those.

BTW, iov_iter_get_pages() never returns more than it had been asked
to; such checks in cifs ought to be removed someday...

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

show more ...

net: fix uninitialised msghdr->sg_from_iter

Because of how struct msghdr is usually initialised some fields and
sg_from_iter in particular might be left out not initialised, so we
can't safely use i

net: fix uninitialised msghdr->sg_from_iter

Because of how struct msghdr is usually initialised some fields and
sg_from_iter in particular might be left out not initialised, so we
can't safely use it in __zerocopy_sg_from_iter().

For now use the callback only when there is ->msg_ubuf set relying on
the fact that they're used together and we properly zero ->msg_ubuf.

Fixes: ebe73a284f4de8 ("net: Allow custom iter handler in msghdr")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Message-Id: <ce8b68b41351488f79fd998b032b3c56e9b1cc6c.1658401817.git.asml.silence@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: Allow custom iter handler in msghdr

Add support for custom iov_iter handling to msghdr. The idea is that
in-kernel subsystems want control over how an SG is split.

Signed-off-by: David Ahern <

net: Allow custom iter handler in msghdr

Add support for custom iov_iter handling to msghdr. The idea is that
in-kernel subsystems want control over how an SG is split.

Signed-off-by: David Ahern <dsahern@kernel.org>
[pavel: move callback into msghdr]
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: keep sk->sk_forward_alloc as small as possible

Currently, tcp_memory_allocated can hit tcp_mem[] limits quite fast.

Each TCP socket can forward allocate up to 2 MB of memory, even after
flow b

net: keep sk->sk_forward_alloc as small as possible

Currently, tcp_memory_allocated can hit tcp_mem[] limits quite fast.

Each TCP socket can forward allocate up to 2 MB of memory, even after
flow became less active.

10,000 sockets can have reserved 20 GB of memory,
and we have no shrinker in place to reclaim that.

Instead of trying to reclaim the extra allocations in some places,
just keep sk->sk_forward_alloc values as small as possible.

This should not impact performance too much now we have per-cpu
reserves: Changes to tcp_memory_allocated should not be too frequent.

For sockets not using SO_RESERVE_MEM:
- idle sockets (no packets in tx/rx queues) have zero forward alloc.
- non idle sockets have a forward alloc smaller than one page.

Note:

- Removal of SK_RECLAIM_CHUNK and SK_RECLAIM_THRESHOLD
is left to MPTCP maintainers as a follow up.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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net: inline skb_zerocopy_iter_dgram

skb_zerocopy_iter_dgram() is a small proxy function, inline it. For
that, move __zerocopy_sg_from_iter into linux/skbuff.h

Signed-off-by: Pavel Begunkov <asml.si

net: inline skb_zerocopy_iter_dgram

skb_zerocopy_iter_dgram() is a small proxy function, inline it. For
that, move __zerocopy_sg_from_iter into linux/skbuff.h

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: remove noblock parameter from skb_recv_datagram()

skb_recv_datagram() has two parameters 'flags' and 'noblock' that are
merged inside skb_recv_datagram() by 'flags | (noblock ? MSG_DONTWAIT : 0

net: remove noblock parameter from skb_recv_datagram()

skb_recv_datagram() has two parameters 'flags' and 'noblock' that are
merged inside skb_recv_datagram() by 'flags | (noblock ? MSG_DONTWAIT : 0)'

As 'flags' may contain MSG_DONTWAIT as value most callers split the 'flags'
into 'flags' and 'noblock' with finally obsolete bit operations like this:

skb_recv_datagram(sk, flags & ~MSG_DONTWAIT, flags & MSG_DONTWAIT, &rc);

And this is not even done consistently with the 'flags' parameter.

This patch removes the obsolete and costly splitting into two parameters
and only performs bit operations when really needed on the caller side.

One missing conversion thankfully reported by kernel test robot. I missed
to enable kunit tests to build the mctp code.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: avoid double accounting for pure zerocopy skbs

Track skbs containing only zerocopy data and avoid charging them to
kernel memory to correctly account the memory utilization for
msg_zerocopy. Al

net: avoid double accounting for pure zerocopy skbs

Track skbs containing only zerocopy data and avoid charging them to
kernel memory to correctly account the memory utilization for
msg_zerocopy. All of the data in such skbs is held in user pages which
are already accounted to user. Before this change, they are charged
again in kernel in __zerocopy_sg_from_iter. The charging in kernel is
excessive because data is not being copied into skb frags. This
excessive charging can lead to kernel going into memory pressure
state which impacts all sockets in the system adversely. Mark pure
zerocopy skbs with a SKBFL_PURE_ZEROCOPY flag and remove
charge/uncharge for data in such skbs.

Initially, an skb is marked pure zerocopy when it is empty and in
zerocopy path. skb can then change from a pure zerocopy skb to mixed
data skb (zerocopy and copy data) if it is at tail of write queue and
there is room available in it and non-zerocopy data is being sent in
the next sendmsg call. At this time sk_mem_charge is done for the pure
zerocopied data and the pure zerocopy flag is unmarked. We found that
this happens very rarely on workloads that pass MSG_ZEROCOPY.

A pure zerocopy skb can later be coalesced into normal skb if they are
next to each other in queue but this patch prevents coalescing from
happening. This avoids complexity of charging when skb downgrades from
pure zerocopy to mixed. This is also rare.

In sk_wmem_free_skb, if it is a pure zerocopy skb, an sk_mem_uncharge
for SKB_TRUESIZE(skb_end_offset(skb)) is done for sk_mem_charge in
tcp_skb_entail for an skb without data.

Testing with the msg_zerocopy.c benchmark between two hosts(100G nics)
with zerocopy showed that before this patch the 'sock' variable in
memory.stat for cgroup2 that tracks sum of sk_forward_alloc,
sk_rmem_alloc and sk_wmem_queued is around 1822720 and with this
change it is 0. This is due to no charge to sk_forward_alloc for
zerocopy data and shows memory utilization for kernel is lowered.

With this commit we don't see the warning we saw in previous commit
which resulted in commit 84882cf72cd774cf16fd338bdbf00f69ac9f9194.

Signed-off-by: Talal Ahmad <talalahmad@google.com>
Acked-by: Arjun Roy <arjunroy@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

udp: fix skb_copy_and_csum_datagram with odd segment sizes

When iteratively computing a checksum with csum_block_add, track the
offset "pos" to correctly rotate in csum_block_add when offset is odd.

udp: fix skb_copy_and_csum_datagram with odd segment sizes

When iteratively computing a checksum with csum_block_add, track the
offset "pos" to correctly rotate in csum_block_add when offset is odd.

The open coded implementation of skb_copy_and_csum_datagram did this.
With the switch to __skb_datagram_iter calling csum_and_copy_to_iter,
pos was reinitialized to 0 on each call.

Bring back the pos by passing it along with the csum to the callback.

Changes v1->v2
- pass csum value, instead of csump pointer (Alexander Duyck)

Link: https://lore.kernel.org/netdev/20210128152353.GB27281@optiplex/
Fixes: 950fcaecd5cc ("datagram: consolidate datagram copy to iter helpers")
Reported-by: Oliver Graute <oliver.graute@gmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20210203192952.1849843-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: datagram: fix some kernel-doc markups

Some identifiers have different names between their prototypes
and the kernel-doc markup.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

net: datagram: fix some kernel-doc markups

Some identifiers have different names between their prototypes
and the kernel-doc markup.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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net: zerocopy: combine pages in zerocopy_sg_from_iter()

Currently, tcp sendmsg(MSG_ZEROCOPY) is building skbs with order-0 fragments.
Compared to standard sendmsg(), these skbs usually contain up to

net: zerocopy: combine pages in zerocopy_sg_from_iter()

Currently, tcp sendmsg(MSG_ZEROCOPY) is building skbs with order-0 fragments.
Compared to standard sendmsg(), these skbs usually contain up to 16 fragments
on arches with 4KB page sizes, instead of two.

This adds considerable costs on various ndo_start_xmit() handlers,
especially when IOMMU is in the picture.

As high performance applications are often using huge pages,
we can try to combine adjacent pages belonging to same
compound page.

Tested on AMD Rome platform, with IOMMU, nominal single TCP flow speed
is roughly doubled (~55Gbit -> ~100Gbit), when user application
is using hugepages.

For reference, nominal single TCP flow speed on this platform
without MSG_ZEROCOPY is ~65Gbit.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: use indirect call wrappers for skb_copy_datagram_iter()

TCP recvmsg() calls skb_copy_datagram_iter(), which
calls an indirect function (cb pointing to simple_copy_to_iter())
for every MSS (frag

net: use indirect call wrappers for skb_copy_datagram_iter()

TCP recvmsg() calls skb_copy_datagram_iter(), which
calls an indirect function (cb pointing to simple_copy_to_iter())
for every MSS (fragment) present in the skb.

CONFIG_RETPOLINE=y forces a very expensive operation
that we can avoid thanks to indirect call wrappers.

This patch gives a 13% increase of performance on
a single flow, if the bottleneck is the thread reading
the TCP socket.

Fixes: 950fcaecd5cc ("datagram: consolidate datagram copy to iter helpers")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: datagram: drop 'destructor' argument from several helpers

The only users for such argument are the UDP protocol and the UNIX
socket family. We can safely reclaim the accounted memory directly
f

net: datagram: drop 'destructor' argument from several helpers

The only users for such argument are the UDP protocol and the UNIX
socket family. We can safely reclaim the accounted memory directly
from the UDP code and, after the previous patch, we can do scm
stats accounting outside the datagram helpers.

Overall this cleans up a bit some datagram-related helpers, and
avoids an indirect call per packet in the UDP receive path.

v1 -> v2:
- call scm_stat_del() only when not peeking - Kirill
- fix build issue with CONFIG_INET_ESPINTCP

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: add queue argument to __skb_wait_for_more_packets and __skb_{,try_}recv_datagram

This will be used by ESP over TCP to handle the queue of IKE messages.

Signed-off-by: Sabrina Dubroca <sd@queas

net: add queue argument to __skb_wait_for_more_packets and __skb_{,try_}recv_datagram

This will be used by ESP over TCP to handle the queue of IKE messages.

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

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net: add READ_ONCE() annotation in __skb_wait_for_more_packets()

__skb_wait_for_more_packets() can be called while other cpus
can feed packets to the socket receive queue.

KCSAN reported :

BUG: KC

net: add READ_ONCE() annotation in __skb_wait_for_more_packets()

__skb_wait_for_more_packets() can be called while other cpus
can feed packets to the socket receive queue.

KCSAN reported :

BUG: KCSAN: data-race in __skb_wait_for_more_packets / __udp_enqueue_schedule_skb

write to 0xffff888102e40b58 of 8 bytes by interrupt on cpu 0:
__skb_insert include/linux/skbuff.h:1852 [inline]
__skb_queue_before include/linux/skbuff.h:1958 [inline]
__skb_queue_tail include/linux/skbuff.h:1991 [inline]
__udp_enqueue_schedule_skb+0x2d7/0x410 net/ipv4/udp.c:1470
__udp_queue_rcv_skb net/ipv4/udp.c:1940 [inline]
udp_queue_rcv_one_skb+0x7bd/0xc70 net/ipv4/udp.c:2057
udp_queue_rcv_skb+0xb5/0x400 net/ipv4/udp.c:2074
udp_unicast_rcv_skb.isra.0+0x7e/0x1c0 net/ipv4/udp.c:2233
__udp4_lib_rcv+0xa44/0x17c0 net/ipv4/udp.c:2300
udp_rcv+0x2b/0x40 net/ipv4/udp.c:2470
ip_protocol_deliver_rcu+0x4d/0x420 net/ipv4/ip_input.c:204
ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231
NF_HOOK include/linux/netfilter.h:305 [inline]
NF_HOOK include/linux/netfilter.h:299 [inline]
ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252
dst_input include/net/dst.h:442 [inline]
ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413
NF_HOOK include/linux/netfilter.h:305 [inline]
NF_HOOK include/linux/netfilter.h:299 [inline]
ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523
__netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5010
__netif_receive_skb+0x37/0xf0 net/core/dev.c:5124
process_backlog+0x1d3/0x420 net/core/dev.c:5955

read to 0xffff888102e40b58 of 8 bytes by task 13035 on cpu 1:
__skb_wait_for_more_packets+0xfa/0x320 net/core/datagram.c:100
__skb_recv_udp+0x374/0x500 net/ipv4/udp.c:1683
udp_recvmsg+0xe1/0xb10 net/ipv4/udp.c:1712
inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838
sock_recvmsg_nosec+0x5c/0x70 net/socket.c:871
___sys_recvmsg+0x1a0/0x3e0 net/socket.c:2480
do_recvmmsg+0x19a/0x5c0 net/socket.c:2601
__sys_recvmmsg+0x1ef/0x200 net/socket.c:2680
__do_sys_recvmmsg net/socket.c:2703 [inline]
__se_sys_recvmmsg net/socket.c:2696 [inline]
__x64_sys_recvmmsg+0x89/0xb0 net/socket.c:2696
do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13035 Comm: syz-executor.3 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: use skb_queue_empty_lockless() in busy poll contexts

Busy polling usually runs without locks.
Let's use skb_queue_empty_lockless() instead of skb_queue_empty()

Also uses READ_ONCE() in __skb_t

net: use skb_queue_empty_lockless() in busy poll contexts

Busy polling usually runs without locks.
Let's use skb_queue_empty_lockless() instead of skb_queue_empty()

Also uses READ_ONCE() in __skb_try_recv_datagram() to address
a similar potential problem.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: use skb_queue_empty_lockless() in poll() handlers

Many poll() handlers are lockless. Using skb_queue_empty_lockless()
instead of skb_queue_empty() is more appropriate.

Signed-off-by: Eric Duma

net: use skb_queue_empty_lockless() in poll() handlers

Many poll() handlers are lockless. Using skb_queue_empty_lockless()
instead of skb_queue_empty() is more appropriate.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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