linux.git/include/linux/skbuff.h, branch v6.14-rc2

xdp: add generic xdp_buff_add_frag()

2024-12-20T03:51:13+00:00

The code piece which would attach a frag to &xdp_buff is almost
identical across the drivers supporting XDP multi-buffer on Rx.
Make it a generic elegant "oneliner".
Also, I see lots of drivers calculating frags_truesize as
`xdp->frame_sz * nr_frags`. I can't say this is fully correct, since
frags might be backed by chunks of different sizes, especially with
stuff like the header split. Even page_pool_alloc() can give you two
different truesizes on two subsequent requests to allocate the same
buffer size. Add a field to &skb_shared_info (unionized as there's no
free slot currently on x86_64) to track the "true" truesize. It can
be used later when updating the skb.

Reviewed-by: Maciej Fijalkowski 
Signed-off-by: Alexander Lobakin 
Link: https://patch.msgid.link/20241218174435.1445282-3-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski

skbuff: allow 2-4-argument skb_frag_dma_map()

2024-12-13T02:23:08+00:00

skb_frag_dma_map(dev, frag, 0, skb_frag_size(frag), DMA_TO_DEVICE)
is repeated across dozens of drivers and really wants a shorthand.
Add a macro which will count args and handle all possible number
from 2 to 5. Semantics:

skb_frag_dma_map(dev, frag) ->
__skb_frag_dma_map(dev, frag, 0, skb_frag_size(frag), DMA_TO_DEVICE)

skb_frag_dma_map(dev, frag, offset) ->
__skb_frag_dma_map(dev, frag, offset, skb_frag_size(frag) - offset,
		   DMA_TO_DEVICE)

skb_frag_dma_map(dev, frag, offset, size) ->
__skb_frag_dma_map(dev, frag, offset, size, DMA_TO_DEVICE)

skb_frag_dma_map(dev, frag, offset, size, dir) ->
__skb_frag_dma_map(dev, frag, offset, size, dir)

No object code size changes for the existing callers. Users passing
less arguments also won't have bigger size comparing to the full
equivalent call.

Signed-off-by: Alexander Lobakin 
Link: https://patch.msgid.link/20241211172649.761483-11-aleksander.lobakin@intel.com
Signed-off-by: Jakub Kicinski

net: reformat kdoc return statements

2024-12-09T22:44:59+00:00

kernel-doc -Wall warns about missing Return: statement for non-void
functions. We have a number of kdocs in our headers which are missing
the colon, IOW they use
 * Return some value
or
 * Returns some value

Having the colon makes some sense, it should help kdoc parser avoid
false positives. So add them. This is mostly done with a sed script,
and removing the unnecessary cases (mostly the comments which aren't
kdoc).

Acked-by: Johannes Berg 
Acked-by: Richard Cochran 
Acked-by: Sergey Ryazanov 
Reviewed-by: Edward Cree 
Acked-by: Alexandra Winter 
Acked-by: Pablo Neira Ayuso 
Link: https://patch.msgid.link/20241205165914.1071102-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski

bpf, xdp: constify some bpf_prog * function arguments

2024-12-06T02:41:06+00:00

In lots of places, bpf_prog pointer is used only for tracing or other
stuff that doesn't modify the structure itself. Same for net_device.
Address at least some of them and add `const` attributes there. The
object code didn't change, but that may prevent unwanted data
modifications and also allow more helpers to have const arguments.

Reviewed-by: Toke Høiland-Jørgensen 
Signed-off-by: Alexander Lobakin 
Signed-off-by: Jakub Kicinski

net: Implement fault injection forcing skb reallocation

2024-11-12T11:05:33+00:00

Introduce a fault injection mechanism to force skb reallocation. The
primary goal is to catch bugs related to pointer invalidation after
potential skb reallocation.

The fault injection mechanism aims to identify scenarios where callers
retain pointers to various headers in the skb but fail to reload these
pointers after calling a function that may reallocate the data. This
type of bug can lead to memory corruption or crashes if the old,
now-invalid pointers are used.

By forcing reallocation through fault injection, we can stress-test code
paths and ensure proper pointer management after potential skb
reallocations.

Add a hook for fault injection in the following functions:

 * pskb_trim_rcsum()
 * pskb_may_pull_reason()
 * pskb_trim()

As the other fault injection mechanism, protect it under a debug Kconfig
called CONFIG_FAIL_SKB_REALLOC.

This patch was *heavily* inspired by Jakub's proposal from:
https://lore.kernel.org/all/20240719174140.47a868e6@kernel.org/

CC: Akinobu Mita 
Suggested-by: Jakub Kicinski 
Signed-off-by: Breno Leitao 
Reviewed-by: Akinobu Mita 
Acked-by: Paolo Abeni 
Acked-by: Guillaume Nault 
Link: https://patch.msgid.link/20241107-fault_v6-v6-1-1b82cb6ecacd@debian.org
Signed-off-by: Paolo Abeni

mm: move the page fragment allocator from page_alloc into its own file

2024-11-11T18:56:26+00:00

Inspired by [1], move the page fragment allocator from page_alloc
into its own c file and header file, as we are about to make more
change for it to replace another page_frag implementation in
sock.c

As this patchset is going to replace 'struct page_frag' with
'struct page_frag_cache' in sched.h, including page_frag_cache.h
in sched.h has a compiler error caused by interdependence between
mm_types.h and mm.h for asm-offsets.c, see [2]. So avoid the compiler
error by moving 'struct page_frag_cache' to mm_types_task.h as
suggested by Alexander, see [3].

1. https://lore.kernel.org/all/20230411160902.4134381-3-dhowells@redhat.com/
2. https://lore.kernel.org/all/15623dac-9358-4597-b3ee-3694a5956920@gmail.com/
3. https://lore.kernel.org/all/CAKgT0UdH1yD=LSCXFJ=YM_aiA4OomD-2wXykO42bizaWMt_HOA@mail.gmail.com/
CC: David Howells 
CC: Linux-MM 
Signed-off-by: Yunsheng Lin 
Acked-by: Andrew Morton 
Reviewed-by: Alexander Duyck 
Link: https://patch.msgid.link/20241028115343.3405838-3-linyunsheng@huawei.com
Signed-off-by: Jakub Kicinski

net: add debug check in skb_reset_mac_header()

2024-11-07T01:29:15+00:00

Make sure (skb->data - skb->head) can fit in skb->mac_header

This needs CONFIG_DEBUG_NET=y.

Signed-off-by: Eric Dumazet 
Reviewed-by: Joe Damato 
Reviewed-by: Xuan Zhuo 
Link: https://patch.msgid.link/20241105174403.850330-8-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: add debug check in skb_reset_network_header()

2024-11-07T01:29:15+00:00

Make sure (skb->data - skb->head) can fit in skb->network_header

This needs CONFIG_DEBUG_NET=y.

Signed-off-by: Eric Dumazet 
Reviewed-by: Joe Damato 
Reviewed-by: Xuan Zhuo 
Link: https://patch.msgid.link/20241105174403.850330-7-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: add debug check in skb_reset_transport_header()

2024-11-07T01:29:14+00:00

Make sure (skb->data - skb->head) can fit in skb->transport_header

This needs CONFIG_DEBUG_NET=y.

Signed-off-by: Eric Dumazet 
Reviewed-by: Joe Damato 
Reviewed-by: Xuan Zhuo 
Link: https://patch.msgid.link/20241105174403.850330-6-edumazet@google.com
Signed-off-by: Jakub Kicinski

net: add debug check in skb_reset_inner_mac_header()

2024-11-07T01:29:14+00:00

Make sure (skb->data - skb->head) can fit in skb->inner_mac_header

This needs CONFIG_DEBUG_NET=y.

Signed-off-by: Eric Dumazet 
Reviewed-by: Joe Damato 
Reviewed-by: Xuan Zhuo 
Link: https://patch.msgid.link/20241105174403.850330-5-edumazet@google.com
Signed-off-by: Jakub Kicinski