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Subject[PATCH bpf-next 2/3] bpf: verifier: use copy_array for jmp_history
Date
Eliminate a couple needless kfree / kmalloc cycles by using
copy_array for jmp_history.

Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
---
kernel/bpf/verifier.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 67d914b26a39..2b9623ac9288 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -926,16 +926,13 @@ static int copy_verifier_state(struct bpf_verifier_state *dst_state,
const struct bpf_verifier_state *src)
{
struct bpf_func_state *dst;
- u32 jmp_sz = sizeof(struct bpf_idx_pair) * src->jmp_history_cnt;
int i, err;

- if (dst_state->jmp_history_cnt < src->jmp_history_cnt) {
- kfree(dst_state->jmp_history);
- dst_state->jmp_history = kmalloc(jmp_sz, GFP_USER);
- if (!dst_state->jmp_history)
- return -ENOMEM;
- }
- memcpy(dst_state->jmp_history, src->jmp_history, jmp_sz);
+ dst_state->jmp_history = copy_array(dst_state->jmp_history, src->jmp_history,
+ src->jmp_history_cnt, sizeof(struct bpf_idx_pair),
+ GFP_USER);
+ if (!dst_state->jmp_history)
+ return -ENOMEM;
dst_state->jmp_history_cnt = src->jmp_history_cnt;

/* if dst has more stack frames then src frame, free them */
--
2.27.0
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