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| author |  Kui-Feng Lee <thinker.li@gmail.com>
| 2024-02-24 14:34:17 -0800 |
|---|---|---|
| committer |  Martin KaFai Lau <martin.lau@kernel.org>
| 2024-03-04 14:09:20 -0800 |
| commit | 187e2af05abe6bf80581490239c449456627d17a (patch) | |
| tree | 573c922b888bd957230d958b50a0756ce457262b /net/bpf | |
| parent | bpf, net: validate struct_ops when updating value. (diff) | |
| download | linux-187e2af05abe6bf80581490239c449456627d17a.tar.gz linux-187e2af05abe6bf80581490239c449456627d17a.tar.bz2 linux-187e2af05abe6bf80581490239c449456627d17a.zip | |
bpf: struct_ops supports more than one page for trampolines.
The BPF struct_ops previously only allowed one page of trampolines.
Each function pointer of a struct_ops is implemented by a struct_ops
bpf program. Each struct_ops bpf program requires a trampoline.
The following selftest patch shows each page can hold a little more
than 20 trampolines.
While one page is more than enough for the tcp-cc usecase,
the sched_ext use case shows that one page is not always enough and hits
the one page limit. This patch overcomes the one page limit by allocating
another page when needed and it is limited to a total of
MAX_IMAGE_PAGES (8) pages which is more than enough for
reasonable usages.
The variable st_map->image has been changed to st_map->image_pages, and
its type has been changed to an array of pointers to pages.
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240224223418.526631-3-thinker.li@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'net/bpf')
| -rw-r--r-- | net/bpf/bpf_dummy_struct_ops.c | 12 |
1 files changed, 4 insertions, 8 deletions
diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c index 02de71719aed..1b5f812e6972 100644 --- a/net/bpf/bpf_dummy_struct_ops.c +++ b/net/bpf/bpf_dummy_struct_ops.c @@ -91,6 +91,7 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, struct bpf_tramp_link *link = NULL; void *image = NULL; unsigned int op_idx; + u32 image_off = 0; int prog_ret; s32 type_id; int err; @@ -114,12 +115,6 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, goto out; } - image = arch_alloc_bpf_trampoline(PAGE_SIZE); - if (!image) { - err = -ENOMEM; - goto out; - } - link = kzalloc(sizeof(*link), GFP_USER); if (!link) { err = -ENOMEM; @@ -133,7 +128,8 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, err = bpf_struct_ops_prepare_trampoline(tlinks, link, &st_ops->func_models[op_idx], &dummy_ops_test_ret_function, - image, image + PAGE_SIZE); + &image, &image_off, + true); if (err < 0) goto out; @@ -147,7 +143,7 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, err = -EFAULT; out: kfree(args); - arch_free_bpf_trampoline(image, PAGE_SIZE); + bpf_struct_ops_image_free(image); if (link) bpf_link_put(&link->link); kfree(tlinks); |