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[213.115.136.2]) by smtp.gmail.com with ESMTPSA id c8sm1989732ejp.124.2021.08.09.02.35.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Aug 2021 02:35:16 -0700 (PDT) From: Johan Almbladh To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org Cc: kafai@fb.com, songliubraving@fb.com, yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, illusionist.neo@gmail.com, zlim.lnx@gmail.com, paulburton@kernel.org, naveen.n.rao@linux.ibm.com, sandipan@linux.ibm.com, luke.r.nels@gmail.com, bjorn@kernel.org, iii@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, davem@davemloft.net, udknight@gmail.com, Johan Almbladh Subject: [PATCH bpf-next 7/7] x86: bpf: Fix comments on tail call count limiting Date: Mon, 9 Aug 2021 11:34:37 +0200 Message-Id: <20210809093437.876558-8-johan.almbladh@anyfinetworks.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210809093437.876558-1-johan.almbladh@anyfinetworks.com> References: <20210809093437.876558-1-johan.almbladh@anyfinetworks.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net 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 --- 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 */