From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f44.google.com (mail-ed1-f44.google.com [209.85.208.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE1242D12F3 for ; Tue, 9 Sep 2025 09:51:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.44 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757411478; cv=none; b=Ksv6ZRxcNKHq5BAiWm+K37rs2olv+Smu6zkXXlN1If7RWbmCAdbmLMvVynDWgicdrskd49KpRIUzP/Ql0ukyqApXCqJT8JIVKTugdsW7jjrBKXitUPSNnLLX/itnFdPuOAAtCXtuE7wkDivyt14ILzZSiVX4H5OP3txCrMfuY1o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757411478; c=relaxed/simple; bh=EJa7vuO9thKOOMPB5lAnUhOysFC9tBG1PWSpmUvUADI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=dERhOaQ/RoNbPJi+rsUn7TRjhj2zuQ7Oxj4QLR36dat2YvWNZR1Z/PVdWzXxUT8aIY2h4G93OZgrb5/4MYwp0UXboGO9BTz/3VmJLe4tQm7E1kTnoSe7TA7NctL4yFGyGls6/B78YGwcRWyUdgLpa9jyKWsTYNb2jpX5nz9B+Yo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com; spf=pass smtp.mailfrom=cloudflare.com; dkim=pass (2048-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b=T9bxLVfO; arc=none smtp.client-ip=209.85.208.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=cloudflare.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=cloudflare.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="T9bxLVfO" Received: by mail-ed1-f44.google.com with SMTP id 4fb4d7f45d1cf-61d143aa4acso8669256a12.2 for ; Tue, 09 Sep 2025 02:51:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google09082023; t=1757411475; x=1758016275; darn=vger.kernel.org; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:from:to:cc:subject:date:message-id:reply-to; bh=ttnhzG/W0udtzRhzi90XxZcALtTq/DsFRIfwgo9QFeM=; b=T9bxLVfO9qnla7gK+DQ6KnfEp9PcZPfMI0juxYwKkIN8L+U0/9QtiM/MaP1IfBGXn8 H/t/poqrtPaoVd4v2pI5jPApbip5ymqBzo/QXB6oTPWTU6l6ehGqMurm/j0ueGzYk1mp UyN+Uqryq1Qioo4GayF6F3vwegkDxolKkUImHyHMIVOwTPddFrkha991ZSM3WSt7vqwb 6WhCG4a7HJKgPKlUbtM3xtDrctarDG4ZK1XEWbvk9kgpP0lF/IQztL9vefue+4jinXqt CKv+I23mTrBPw7hAgNBaBC6AhvSOMOgx/mxm5aQFarcQEUmOV8+uvi7loHgjHQzEjuyE sUlg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757411475; x=1758016275; h=mime-version:message-id:date:references:in-reply-to:subject:cc:to :from:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=ttnhzG/W0udtzRhzi90XxZcALtTq/DsFRIfwgo9QFeM=; b=bEFemK47j3dODHA9xnAyzEhvteW5ptp2lzRbakdLxHN8mEnU3ONnKMsmRwVusCMMuQ kKMqOFwj8hty/f3PdpcYt7KTQoKcundVBgwDnpRKyE/h6SdWyI5vkagQYLdd10uoZmfk W4qiaw/4rSuYgl+VRxpZ7rv6T/tqndDXXrnRayFMyErMFBdua5q2hwNI53jh7BCnyF73 3NdYOWli42IYreIMVgLQD4QU5Q43Pt85sYTfei6vVtNR0pa/iHqDW02VmV5WeeGYtNFE qjAG+SCXPi5d1HnkixT/o78Xmkwn0wsLtaVhH/PrHRCcgg5IeyNlwybGBi6xE/bx7cCA BjOw== X-Forwarded-Encrypted: i=1; AJvYcCWMOsD2Gtr1xuZrsy0umcImww70FwPX6sbqaRfXsBKW3AyJaztuMD+k/KW1LD7GmZ3nhkw=@vger.kernel.org X-Gm-Message-State: AOJu0Yzb8PMTNMjlHJyV3DXvL6jKhFJtPYBvPRwboYM1pkZpX5uQQzIi jCiasFRxWngfqUTFaRfhlQhh4q7SIDCAHVqEYqz9CYBtpDTfs9fcOS3OLQ5Rgt7xDwk= X-Gm-Gg: ASbGncsPUZEecVXKynK/PBxa94vaoBu8wx+fbfddPCbmVV//67s5VUi1Y42KPWHAHxG LcZ4329ZwbPEI5VCSmP9gXsQDaDP4yxI7B3g6V3BF8qzd3SKGG+91XQFafJN24MzSeq9mpas+7C NRd24FDdWFOCy+zglYepu6RnxZ8Z8z3R2d9MHvHClO189aNxw2YGFG77ZY7koeRI4QE+OXZn3gs AkhrwP8neH4aD3vo+BJgShpWot3uSnlKvoe4nhQCsiAhmmB+LZa551bXmZPXHsfrJyAzL/Dm2EJ 0+/Iook6wqQBx9dGEB6UK9NyiKb3FUL1jgFxcqfKyvHh9Qe7iymMnwYaJDMll3vvEgGblGhtutb RDkowWkRJbNSfs9JrMS61WzmC X-Google-Smtp-Source: AGHT+IHL1A4xOak1CBPxy0OgkkpejE8KlndP1MveZHrFbWUYAt9r14ZZNm1gXyDoH8GW8mDi0O4o2A== X-Received: by 2002:a05:6402:1d52:b0:626:6ce5:4b8 with SMTP id 4fb4d7f45d1cf-6266ce50670mr9703104a12.32.1757411474932; Tue, 09 Sep 2025 02:51:14 -0700 (PDT) Received: from cloudflare.com ([2a09:bac5:5063:295f::41f:a]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-62bfe99febdsm923822a12.8.2025.09.09.02.51.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Sep 2025 02:51:14 -0700 (PDT) From: Jakub Sitnicki To: Michal Luczaj Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH bpf-next 1/5] selftests/bpf: sockmap_redir: Simplify try_recv() In-Reply-To: <20250905-redir-test-pass-drop-v1-1-9d9e43ff40df@rbox.co> (Michal Luczaj's message of "Fri, 05 Sep 2025 13:11:41 +0200") References: <20250905-redir-test-pass-drop-v1-0-9d9e43ff40df@rbox.co> <20250905-redir-test-pass-drop-v1-1-9d9e43ff40df@rbox.co> Date: Tue, 09 Sep 2025 11:51:13 +0200 Message-ID: <87ikhs54z2.fsf@cloudflare.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Fri, Sep 05, 2025 at 01:11 PM +02, Michal Luczaj wrote: > try_recv() was meant to support both @expect_success cases, but all the > callers use @expect_success=false anyway. Drop the unused logic and fold in > MSG_DONTWAIT. Adapt callers. > > Subtle change here: recv() return value of 0 will also be considered (an > unexpected) success. > > Signed-off-by: Michal Luczaj > --- > .../selftests/bpf/prog_tests/sockmap_redir.c | 25 +++++++++------------- > 1 file changed, 10 insertions(+), 15 deletions(-) > > diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c b/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c > index 9c461d93113db20de65ac353f92dfdbe32ffbd3b..c1bf1076e8152b7d83c3e07e2dce746b5a39cf7e 100644 > --- a/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c > +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_redir.c > @@ -144,17 +144,14 @@ static void get_redir_params(struct redir_spec *redir, > *redirect_flags = 0; > } > > -static void try_recv(const char *prefix, int fd, int flags, bool expect_success) > +static void fail_recv(const char *prefix, int fd, int more_flags) > { > ssize_t n; > char buf; > > - errno = 0; > - n = recv(fd, &buf, 1, flags); > - if (n < 0 && expect_success) > - FAIL_ERRNO("%s: unexpected failure: retval=%zd", prefix, n); > - if (!n && !expect_success) > - FAIL("%s: expected failure: retval=%zd", prefix, n); > + n = recv(fd, &buf, 1, MSG_DONTWAIT | more_flags); > + if (n >= 0) > + FAIL("%s: unexpected success: retval=%zd", prefix, n); > } This bit, which you highlighted in the description, I don't get. If we're expecting to receive exactly one byte, why treat a short read as a succcess? Why not make it a strict "n != 1" check? [...]