From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 16E7F1C863B; Mon, 8 Sep 2025 20:44:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757364280; cv=none; b=QWZhIAk4HGoi0hmLEtk7OsEWx8Q768qVnf+aMEEGND1wPz5VyPfeZMGXfQOyXZEaP+Vcpwk4YDflFbH/kChSbpS2cxcvxJ+lB5NVnFJoHigEYAKvQ/zVYgWuOw/XyqVor/XfXAHWBDp9ZteKPkzbmIc7UcMeDjgs1KlooEdgL0U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757364280; c=relaxed/simple; bh=+UaQJJ9kveq5w+zMdLW3l1Tdxyl5Xf3XW3yKboz8Rwc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tA0k5IksIWQr4zgEBPyV/ZsiucUuSS4lSCdm1xAzW+OsLJdrpcrqB2a7uMhRReq8jxY57KhdMb2+Y2SJpdqjpup/IrtTZMRakegdI8fvyE01C0diDhQRtHDl8d7r105EQFHFgyqx0krdB+zAkJKsoglSULG43ovHOg9XKrUb2e4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=in1N8aSd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="in1N8aSd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C765C4CEF1; Mon, 8 Sep 2025 20:44:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757364279; bh=+UaQJJ9kveq5w+zMdLW3l1Tdxyl5Xf3XW3yKboz8Rwc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=in1N8aSdMwY7UqLQ5gJ3Rv/Jg5RlH4YP0yewS6QkRacRakFWcP3v68iwP0wkZDj/E bBx0QxQZjXy6iH4XdawKN/Z66ZsfkC4eKMD+K6zh/VnZbGjXRI76HxRwAqhIyass3x BjEJb3nY17IUYXpXvmx8H3M1FGHzdoHgLXPgaZMA3MBuISEVW0vV/D3F4aZSJYQWuq b3j/70Pu6Fs+WAKd3K9NcyoYI7QGblUK14EtZMEdUESfo+j+lkRKDb2oFIs/MjYzA2 tEwlHhm/w1rF7Q+hAorK7xCpef7fwI1xvaLk55WeAISxb74gESxdSeNmuJcU6F01oT 1NV+euPt/NQqg== Message-ID: <7726e657-585c-42d3-aff2-c991eed42361@kernel.org> Date: Mon, 8 Sep 2025 14:44:38 -0600 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next] net: devmem: expose tcp_recvmsg_locked errors To: Stanislav Fomichev , netdev@vger.kernel.org Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, ncardwell@google.com, kuniyu@google.com, horms@kernel.org, linux-kernel@vger.kernel.org, Mina Almasry References: <20250908175045.3422388-1-sdf@fomichev.me> Content-Language: en-US From: David Ahern In-Reply-To: <20250908175045.3422388-1-sdf@fomichev.me> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/8/25 11:50 AM, Stanislav Fomichev wrote: > tcp_recvmsg_dmabuf can export the following errors: > - EFAULT when linear copy fails > - ETOOSMALL when cmsg put fails > - ENODEV if one of the frags is readable > - ENOMEM on xarray failures > > But they are all ignored and replaced by EFAULT in the caller > (tcp_recvmsg_locked). Expose real error to the userspace to > add more transparency on what specifically fails. > > In non-devmem case (skb_copy_datagram_msg) doing `if (!copied) > copied=-EFAULT` is ok because skb_copy_datagram_msg can return only EFAULT. > > Cc: Mina Almasry > Signed-off-by: Stanislav Fomichev > --- > net/ipv4/tcp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > Reviewed-by: David Ahern