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 50DA821767D; Thu, 2 Apr 2026 00:44:42 +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=1775090682; cv=none; b=rinDrnHymZDoARU4C6hn2hme1fj/9DXd68b/4knWbqHeOMGG8bRHlQgYMMJOmFUjAKtDEdFWGMqGZtJl10Djcm9Rz2sTr8wJV9lNOUt18hBI9P2B5GxVLK0fFcKcxcr/Cjc09OBbs/WnSfe7/pCxu+Siwfx67hv/jn/7gABrdVs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775090682; c=relaxed/simple; bh=GnHscPrNJRppDEXonawDI1TlSlpSxWRDtvMK8mVhTkg=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=kQWWAN/fPoJghSDQYve9C2Iv53xOTkQ1ml004uXIYFOe4oVUuwXjbPfOMvN+XeyxuJkBymV1kIImGi+mIqYReKqlYU2IGiRZUBC6r9FEGhKTrxdQ8YnPdBrJPmjcX6BHHImYZugjTIGYfT1CV7XJ8d+kHUKSlCK6G/xqudGZZNM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=HA/tmooA; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="HA/tmooA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FD0EC4CEF7; Thu, 2 Apr 2026 00:44:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1775090681; bh=GnHscPrNJRppDEXonawDI1TlSlpSxWRDtvMK8mVhTkg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=HA/tmooAm7H0WnStcyUYwNwCrxEXDDjkCXD8RRMBEBxkJmTWFMu9+AXrRydUGHzU1 DSdPbQJ0TMVDvsj4SHJBuCZvEOLxbj4HNdamPG5v9/aOnwqxKrwRph4/HY1P7xSSkm dfY8bLps097wtInJHSQhc/5nmZ67k9zwObuphCTg= Date: Wed, 1 Apr 2026 17:44:40 -0700 From: Andrew Morton To: Anthony Yznaga Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, david@kernel.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, jannh@google.com, pfalcato@suse.de, Jason@zx2c4.com, shuah@kernel.org Subject: Re: [PATCH 1/2] mm: fix mmap errno value when MAP_DROPPABLE is not supported Message-Id: <20260401174440.0f85ea303f0a027b50d99e5d@linux-foundation.org> In-Reply-To: <20260402003417.438037-2-anthony.yznaga@oracle.com> References: <20260402003417.438037-1-anthony.yznaga@oracle.com> <20260402003417.438037-2-anthony.yznaga@oracle.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 1 Apr 2026 17:34:16 -0700 Anthony Yznaga wrote: > On configs where MAP_DROPPABLE is not supported (currently any 32-bit > config except for PPC32), mmap fails with errno set to ENOTSUPP. > However, ENOTSUPP is not a standard error value that userspace knows > about. The acceptable userspace-visible errno to use is EOPNOTSUPP. > checkpatch.pl has a warning to this affect. Sounds very reasonable. EOPNOTSUPP is clearly a networking thing so what on earth is it doing coming out of mmap code? Our poor operator is now looking at a networking error code and wondering what this supposedly non-networking application is up to. But just that's a pet peeve - I lost that one decades ago. > Fixes: 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always lazily freeable mappings") Nearly two years ago so I think I'll add this to mm-unstable for 7.1-rc1 and shall let it trickle back a little more slowly than might a 7.0-rcX hotfix.