[PATCH bpf-next 7/7] x86: bpf: Fix comments on tail call count limiting
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STALE1894d
From: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Date: 2021-08-09 09:35:22
Also in:
bpf
Subsystem:
bpf jit for x86 32-bit, bpf [general] (safe dynamic programs and tools), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Wang YanQing, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Before, the comments in the 32-bit eBPF JIT claimed that up to MAX_TAIL_CALL_CNT + 1 tail calls were allowed, when in fact the implementation was using the correct limit of MAX_TAIL_CALL_CNT. Now, the comments are in line with what the code actually does. Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> --- arch/x86/net/bpf_jit_comp32.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp32.c b/arch/x86/net/bpf_jit_comp32.c
index 3bfda5f502cb..8db9ab11abda 100644
--- a/arch/x86/net/bpf_jit_comp32.c
+++ b/arch/x86/net/bpf_jit_comp32.c@@ -1272,7 +1272,7 @@ static void emit_epilogue(u8 **pprog, u32 stack_depth) * ... bpf_tail_call(void *ctx, struct bpf_array *array, u64 index) ... * if (index >= array->map.max_entries) * goto out; - * if (++tail_call_cnt > MAX_TAIL_CALL_CNT) + * if (tail_call_cnt++ >= MAX_TAIL_CALL_CNT) * goto out; * prog = array->ptrs[index]; * if (prog == NULL)
@@ -1307,7 +1307,7 @@ static void emit_bpf_tail_call(u8 **pprog) EMIT2(IA32_JBE, jmp_label(jmp_label1, 2)); /* - * if (tail_call_cnt > MAX_TAIL_CALL_CNT) + * if (tail_call_cnt >= MAX_TAIL_CALL_CNT) * goto out; */ lo = (u32)MAX_TAIL_CALL_CNT;
@@ -1321,7 +1321,7 @@ static void emit_bpf_tail_call(u8 **pprog) /* cmp ecx,lo */ EMIT3(0x83, add_1reg(0xF8, IA32_ECX), lo); - /* ja out */ + /* jae out */ EMIT2(IA32_JAE, jmp_label(jmp_label1, 2)); /* add eax,0x1 */
--
2.25.1