BMC/Intel-BMC/linux.git/net/core/xdp.c, branch dev-5.10-intel

xdp: fix xdp_return_frame() kernel BUG throw for page_pool memory model

2021-04-14T06:42:09+00:00

[ Upstream commit 622d13694b5f048c01caa7ba548498d9880d4cb0 ] xdp_return_frame() may be called outside of NAPI context to return xdpf back to page_pool. xdp_return_frame() calls __xdp_return() with napi_direct = false. For page_pool memory model, __xdp_return() calls xdp_return_frame_no_direct() unconditionally and below false negative kernel BUG throw happened under preempt-rt build: [ 430.450355] BUG: using smp_processor_id() in preemptible [00000000] code: modprobe/3884 [ 430.451678] caller is __xdp_return+0x1ff/0x2e0 [ 430.452111] CPU: 0 PID: 3884 Comm: modprobe Tainted: G U E 5.12.0-rc2+ #45 Changes in v2: - This patch fixes the issue by making xdp_return_frame_no_direct() is only called if napi_direct = true, as recommended for better by Jesper Dangaard Brouer. Thanks! Fixes: 2539650fadbf ("xdp: Helpers for disabling napi_direct of xdp_return_frame") Signed-off-by: Ong Boon Leong Acked-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

xdp: Remove the xdp_attachment_flags_ok() callback

2020-12-09T15:27:42+00:00

Since commit 7f0a838254bd ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device"), the XDP program attachment info is now maintained in the core code. This interacts badly with the xdp_attachment_flags_ok() check that prevents unloading an XDP program with different load flags than it was loaded with. In practice, two kinds of failures are seen: - An XDP program loaded without specifying a mode (and which then ends up in driver mode) cannot be unloaded if the program mode is specified on unload. - The dev_xdp_uninstall() hook always calls the driver callback with the mode set to the type of the program but an empty flags argument, which means the flags_ok() check prevents the program from being removed, leading to bpf prog reference leaks. The original reason this check was added was to avoid ambiguity when multiple programs were loaded. With the way the checks are done in the core now, this is quite simple to enforce in the core code, so let's add a check there and get rid of the xdp_attachment_flags_ok() callback entirely. Fixes: 7f0a838254bd ("bpf, xdp: Maintain info on attached XDP BPF programs in net_device") Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Daniel Borkmann Acked-by: Jakub Kicinski Link: https://lore.kernel.org/bpf/160752225751.110217.10267659521308669050.stgit@toke.dk

xdp: Handle MEM_TYPE_XSK_BUFF_POOL correctly in xdp_return_buff()

2020-11-30T22:00:26+00:00

It turns out that it does exist a path where xdp_return_buff() is being passed an XDP buffer of type MEM_TYPE_XSK_BUFF_POOL. This path is when AF_XDP zero-copy mode is enabled, and a buffer is redirected to a DEVMAP with an attached XDP program that drops the buffer. This change simply puts the handling of MEM_TYPE_XSK_BUFF_POOL back into xdp_return_buff(). Fixes: 82c41671ca4f ("xdp: Simplify xdp_return_{frame, frame_rx_napi, buff}") Reported-by: Maxim Mikityanskiy Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann Acked-by: Maxim Mikityanskiy Link: https://lore.kernel.org/bpf/20201127171726.123627-1-bjorn.topel@gmail.com

bpf, xdp: Remove XDP_QUERY_PROG and XDP_QUERY_PROG_HW XDP commands

2020-07-26T03:37:02+00:00

Now that BPF program/link management is centralized in generic net_device code, kernel code never queries program id from drivers, so XDP_QUERY_PROG/XDP_QUERY_PROG_HW commands are unnecessary. This patch removes all the implementations of those commands in kernel, along the xdp_attachment_query(). This patch was compile-tested on allyesconfig. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200722064603.3350758-10-andriin@fb.com

xdp: Handle frame_sz in xdp_convert_zc_to_xdp_frame()

2020-06-17T16:58:15+00:00

In commit 34cc0b338a61 we only handled the frame_sz in convert_to_xdp_frame(). This patch will also handle frame_sz in xdp_convert_zc_to_xdp_frame(). Fixes: 34cc0b338a61 ("xdp: Xdp_frame add member frame_sz and handle in convert_to_xdp_frame") Signed-off-by: Hangbin Liu Signed-off-by: Alexei Starovoitov Acked-by: Jesper Dangaard Brouer Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20200616103518.2963410-1-liuhangbin@gmail.com

xdp: Simplify xdp_return_{frame, frame_rx_napi, buff}

2020-05-22T00:31:27+00:00

The xdp_return_{frame,frame_rx_napi,buff} function are never used, except in xdp_convert_zc_to_xdp_frame(), by the MEM_TYPE_XSK_BUFF_POOL memory type. To simplify and reduce code, change so that xdp_convert_zc_to_xdp_frame() calls xsk_buff_free() directly since the type is know, and remove MEM_TYPE_XSK_BUFF_POOL from the switch statement in __xdp_return() function. Suggested-by: Maxim Mikityanskiy Signed-off-by: Björn Töpel Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-14-bjorn.topel@gmail.com

xsk: Remove MEM_TYPE_ZERO_COPY and corresponding code

2020-05-22T00:31:27+00:00

There are no users of MEM_TYPE_ZERO_COPY. Remove all corresponding code, including the "handle" member of struct xdp_buff. rfc->v1: Fixed spelling in commit message. (Björn) Signed-off-by: Björn Töpel Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-13-bjorn.topel@gmail.com

xsk: Introduce AF_XDP buffer allocation API

2020-05-22T00:31:26+00:00

In order to simplify AF_XDP zero-copy enablement for NIC driver developers, a new AF_XDP buffer allocation API is added. The implementation is based on a single core (single producer/consumer) buffer pool for the AF_XDP UMEM. A buffer is allocated using the xsk_buff_alloc() function, and returned using xsk_buff_free(). If a buffer is disassociated with the pool, e.g. when a buffer is passed to an AF_XDP socket, a buffer is said to be released. Currently, the release function is only used by the AF_XDP internals and not visible to the driver. Drivers using this API should register the XDP memory model with the new MEM_TYPE_XSK_BUFF_POOL type. The API is defined in net/xdp_sock_drv.h. The buffer type is struct xdp_buff, and follows the lifetime of regular xdp_buffs, i.e. the lifetime of an xdp_buff is restricted to a NAPI context. In other words, the API is not replacing xdp_frames. In addition to introducing the API and implementations, the AF_XDP core is migrated to use the new APIs. rfc->v1: Fixed build errors/warnings for m68k and riscv. (kbuild test robot) Added headroom/chunk size getter. (Maxim/Björn) v1->v2: Swapped SoBs. (Maxim) v2->v3: Initialize struct xdp_buff member frame_sz. (Björn) Add API to query the DMA address of a frame. (Maxim) Do DMA sync for CPU till the end of the frame to handle possible growth (frame_sz). (Maxim) Signed-off-by: Björn Töpel Signed-off-by: Maxim Mikityanskiy Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-6-bjorn.topel@gmail.com

xdp: Xdp_frame add member frame_sz and handle in convert_to_xdp_frame

2020-05-15T04:21:54+00:00

Use hole in struct xdp_frame, when adding member frame_sz, which keeps same sizeof struct (32 bytes) Drivers ixgbe and sfc had bug cases where the necessary/expected tailroom was not reserved. This can lead to some hard to catch memory corruption issues. Having the drivers frame_sz this can be detected when packet length/end via xdp->data_end exceed the xdp_data_hard_end pointer, which accounts for the reserved the tailroom. When detecting this driver issue, simply fail the conversion with NULL, which results in feedback to driver (failing xdp_do_redirect()) causing driver to drop packet. Given the lack of consistent XDP stats, this can be hard to troubleshoot. And given this is a driver bug, we want to generate some more noise in form of a WARN stack dump (to ID the driver code that inlined convert_to_xdp_frame). Inlining the WARN macro is problematic, because it adds an asm instruction (on Intel CPUs ud2) what influence instruction cache prefetching. Thus, introduce xdp_warn and macro XDP_WARN, to avoid this and at the same time make identifying the function and line of this inlined function easier. Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Alexei Starovoitov Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/158945337313.97035.10015729316710496600.stgit@firesoul

net: page_pool: API cleanup and comments

2020-02-20T18:09:25+00:00

Functions starting with __ usually indicate those which are exported, but should not be called directly. Update some of those declared in the API and make it more readable. page_pool_unmap_page() and page_pool_release_page() were doing exactly the same thing calling __page_pool_clean_page(). Let's rename __page_pool_clean_page() to page_pool_release_page() and export it in order to show up on perf logs and get rid of page_pool_unmap_page(). Finally rename __page_pool_put_page() to page_pool_put_page() since we can now directly call it from drivers and rename the existing page_pool_put_page() to page_pool_put_full_page() since they do the same thing but the latter is trying to sync the full DMA area. This patch also updates netsec, mvneta and stmmac drivers which use those functions. Suggested-by: Jonathan Lemon Acked-by: Toke Høiland-Jørgensen Acked-by: Jesper Dangaard Brouer Signed-off-by: Ilias Apalodimas Signed-off-by: David S. Miller