diff options
| author | Hou Tao <houtao1@huawei.com> | 2024-10-30 18:05:13 +0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-10-30 12:13:46 -0700 |
| commit | 62a898b07b83f6f407003d8a70f0827a5af08a59 (patch) | |
| tree | e101cca91dec00f46cc3a9e4aaeaf8cb6a451ca1 /kernel | |
| parent | 101ccfbabf4738041273ce64e2b116cf440dea13 (diff) | |
bpf: Add bpf_mem_alloc_check_size() helper
Introduce bpf_mem_alloc_check_size() to check whether the allocation
size exceeds the limitation for the kmalloc-equivalent allocator. The
upper limit for percpu allocation is LLIST_NODE_SZ bytes larger than
non-percpu allocation, so a percpu argument is added to the helper.
The helper will be used in the following patch to check whether the size
parameter passed to bpf_mem_alloc() is too big.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20241030100516.3633640-3-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/memalloc.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index b3858a76e0b3..146f5b57cfb1 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -35,6 +35,8 @@ */ #define LLIST_NODE_SZ sizeof(struct llist_node) +#define BPF_MEM_ALLOC_SIZE_MAX 4096 + /* similar to kmalloc, but sizeof == 8 bucket is gone */ static u8 size_index[24] __ro_after_init = { 3, /* 8 */ @@ -65,7 +67,7 @@ static u8 size_index[24] __ro_after_init = { static int bpf_mem_cache_idx(size_t size) { - if (!size || size > 4096) + if (!size || size > BPF_MEM_ALLOC_SIZE_MAX) return -1; if (size <= 192) @@ -1005,3 +1007,13 @@ void notrace *bpf_mem_cache_alloc_flags(struct bpf_mem_alloc *ma, gfp_t flags) return !ret ? NULL : ret + LLIST_NODE_SZ; } + +int bpf_mem_alloc_check_size(bool percpu, size_t size) +{ + /* The size of percpu allocation doesn't have LLIST_NODE_SZ overhead */ + if ((percpu && size > BPF_MEM_ALLOC_SIZE_MAX) || + (!percpu && size > BPF_MEM_ALLOC_SIZE_MAX - LLIST_NODE_SZ)) + return -E2BIG; + + return 0; +} |