kernel/linux.git/include/net/xdp.h, branch v6.1.168

bpf: Clear pfmemalloc flag when freeing all fragments

2025-12-06T21:12:17+00:00

[ Upstream commit 8f12d1137c2382c80aada8e05d7cc650cd4e403c ] It is possible for bpf_xdp_adjust_tail() to free all fragments. The kfunc currently clears the XDP_FLAGS_HAS_FRAGS bit, but not XDP_FLAGS_FRAGS_PF_MEMALLOC. So far, this has not caused a issue when building sk_buff from xdp_buff since all readers of xdp_buff->flags use the flag only when there are fragments. Clear the XDP_FLAGS_FRAGS_PF_MEMALLOC bit as well to make the flags correct. Signed-off-by: Amery Hung Signed-off-by: Martin KaFai Lau Reviewed-by: Maciej Fijalkowski Link: https://patch.msgid.link/20250922233356.3356453-2-ameryhung@gmail.com Signed-off-by: Sasha Levin

xdp: Adjust xdp_frame layout to avoid using bitfields

2022-09-26T20:28:19+00:00

Practical experience (and advice from Alexei) tell us that bitfields in structs lead to un-optimized assembly code. I've verified this change does lead to better x86_64 assembly, both via objdump and playing with code snippets in godbolt.org. Using scripts/bloat-o-meter shows the code size is reduced with 24 bytes for xdp_convert_buff_to_frame() that gets inlined e.g. in i40e_xmit_xdp_tx_ring() which were used for microbenchmarking. Microbenchmarking results do show improvements, but very small and varying between 0.5 to 2 nanosec improvement per packet. The member @metasize is changed from u8 to u32. Future users of this area could split this into two u16 fields. I've also benchmarked with two u16 fields showing equal performance gains and code size reduction. The moved member @frame_sz doesn't change sizeof struct due to existing padding. Like xdp_buff member @frame_sz is placed next to @flags, which allows compiler to optimize assignment of these. Signed-off-by: Jesper Dangaard Brouer Link: https://lore.kernel.org/r/166393728005.2213882.4162674859542409548.stgit@firesoul Signed-off-by: Jakub Kicinski

net: veth: Account total xdp_frame len running ndo_xdp_xmit

2022-03-17T19:33:52+00:00

Even if this is a theoretical issue since it is not possible to perform XDP_REDIRECT on a non-linear xdp_frame, veth driver does not account paged area in ndo_xdp_xmit function pointer. Introduce xdp_get_frame_len utility routine to get the xdp_frame full length and account total frame size running XDP_REDIRECT of a non-linear xdp frame into a veth device. Signed-off-by: Lorenzo Bianconi Signed-off-by: Daniel Borkmann Acked-by: Toke Hoiland-Jorgensen Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/54f9fd3bb65d190daf2c0bbae2f852ff16cfbaa0.1646989407.git.lorenzo@kernel.org

bpf: add frags support to the bpf_xdp_adjust_tail() API

2022-01-21T22:14:02+00:00

This change adds support for tail growing and shrinking for XDP frags. When called on a non-linear packet with a grow request, it will work on the last fragment of the packet. So the maximum grow size is the last fragments tailroom, i.e. no new buffer will be allocated. A XDP frags capable driver is expected to set frag_size in xdp_rxq_info data structure to notify the XDP core the fragment size. frag_size set to 0 is interpreted by the XDP core as tail growing is not allowed. Introduce __xdp_rxq_info_reg utility routine to initialize frag_size field. When shrinking, it will work from the last fragment, all the way down to the base buffer depending on the shrinking size. It's important to mention that once you shrink down the fragment(s) are freed, so you can not grow again to the original size. Acked-by: Toke Hoiland-Jorgensen Acked-by: John Fastabend Acked-by: Jakub Kicinski Co-developed-by: Lorenzo Bianconi Signed-off-by: Lorenzo Bianconi Signed-off-by: Eelco Chaudron Link: https://lore.kernel.org/r/eabda3485dda4f2f158b477729337327e609461d.1642758637.git.lorenzo@kernel.org Signed-off-by: Alexei Starovoitov

bpf: introduce bpf_xdp_get_buff_len helper

2022-01-21T22:14:02+00:00

Introduce bpf_xdp_get_buff_len helper in order to return the xdp buffer total size (linear and paged area) Acked-by: Toke Hoiland-Jorgensen Acked-by: John Fastabend Signed-off-by: Lorenzo Bianconi Link: https://lore.kernel.org/r/aac9ac3504c84026cf66a3c71b7c5ae89bc991be.1642758637.git.lorenzo@kernel.org Signed-off-by: Alexei Starovoitov

xdp: add frags support to xdp_return_{buff/frame}

2022-01-21T22:14:01+00:00

Take into account if the received xdp_buff/xdp_frame is non-linear recycling/returning the frame memory to the allocator or into xdp_frame_bulk. Acked-by: Toke Hoiland-Jorgensen Acked-by: John Fastabend Signed-off-by: Lorenzo Bianconi Link: https://lore.kernel.org/r/a961069febc868508ce1bdf5e53a343eb4e57cb2.1642758637.git.lorenzo@kernel.org Signed-off-by: Alexei Starovoitov

net: xdp: add xdp_update_skb_shared_info utility routine

2022-01-21T22:14:01+00:00

Introduce xdp_update_skb_shared_info routine to update frags array metadata in skb_shared_info data structure converting to a skb from a xdp_buff or xdp_frame. According to the current skb_shared_info architecture in xdp_frame/xdp_buff and to the xdp frags support, there is no need to run skb_add_rx_frag() and reset frags array converting the buffer to a skb since the frag array will be in the same position for xdp_buff/xdp_frame and for the skb, we just need to update memory metadata. Introduce XDP_FLAGS_PF_MEMALLOC flag in xdp_buff_flags in order to mark the xdp_buff or xdp_frame as under memory-pressure if pages of the frags array are under memory pressure. Doing so we can avoid looping over all fragments in xdp_update_skb_shared_info routine. The driver is expected to set the flag constructing the xdp_buffer using xdp_buff_set_frag_pfmemalloc utility routine. Rely on xdp_update_skb_shared_info in __xdp_build_skb_from_frame routine converting the non-linear xdp_frame to a skb after performing a XDP_REDIRECT. Acked-by: Toke Hoiland-Jorgensen Acked-by: John Fastabend Acked-by: Jesper Dangaard Brouer Signed-off-by: Lorenzo Bianconi Link: https://lore.kernel.org/r/bfd23fb8a8d7438724f7819c567cdf99ffd6226f.1642758637.git.lorenzo@kernel.org Signed-off-by: Alexei Starovoitov

xdp: introduce flags field in xdp_buff/xdp_frame

2022-01-21T22:14:01+00:00

Introduce flags field in xdp_frame and xdp_buffer data structures to define additional buffer features. At the moment the only supported buffer feature is frags bit (XDP_FLAGS_HAS_FRAGS). frags bit is used to specify if this is a linear buffer (XDP_FLAGS_HAS_FRAGS not set) or a frags frame (XDP_FLAGS_HAS_FRAGS set). In the latter case the driver is expected to initialize the skb_shared_info structure at the end of the first buffer to link together subsequent buffers belonging to the same frame. Acked-by: Toke Hoiland-Jorgensen Acked-by: John Fastabend Acked-by: Jesper Dangaard Brouer Signed-off-by: Lorenzo Bianconi Link: https://lore.kernel.org/r/e389f14f3a162c0a5bc6a2e1aa8dd01a90be117d.1642758637.git.lorenzo@kernel.org Signed-off-by: Alexei Starovoitov

xdp: Allow registering memory model without rxq reference

2022-01-06T03:46:32+00:00

The functions that register an XDP memory model take a struct xdp_rxq as parameter, but the RXQ is not actually used for anything other than pulling out the struct xdp_mem_info that it embeds. So refactor the register functions and export variants that just take a pointer to the xdp_mem_info. This is in preparation for enabling XDP_REDIRECT in bpf_prog_run(), using a page_pool instance that is not connected to any network device. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20220103150812.87914-2-toke@redhat.com

bpf, xdp, docs: Correct some English grammar and spelling

2021-09-30T21:23:49+00:00

Header DOC on include/net/xdp.h contained a few English grammer and spelling errors. Signed-off-by: Kev Jackson Signed-off-by: Daniel Borkmann Acked-by: Jesper Dangaard Brouer Link: https://lore.kernel.org/bpf/YVVaWmKqA8l9Tm4J@kev-VirtualBox