From: Andrew Morton <akpm@linux-foundation.org>
To: Anthony Yznaga <anthony.yznaga@oracle.com>
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
Date: Wed, 1 Apr 2026 17:44:40 -0700 [thread overview]
Message-ID: <20260401174440.0f85ea303f0a027b50d99e5d@linux-foundation.org> (raw)
In-Reply-To: <20260402003417.438037-2-anthony.yznaga@oracle.com>
On Wed, 1 Apr 2026 17:34:16 -0700 Anthony Yznaga <anthony.yznaga@oracle.com> 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.
next prev parent reply other threads:[~2026-04-02 0:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-02 0:34 [PATCH 0/2] fix MAP_DROPPABLE not supported errno Anthony Yznaga
2026-04-02 0:34 ` [PATCH 1/2] mm: fix mmap errno value when MAP_DROPPABLE is not supported Anthony Yznaga
2026-04-02 0:44 ` Andrew Morton [this message]
2026-04-02 7:17 ` David Hildenbrand (Arm)
2026-04-02 23:13 ` anthony.yznaga
2026-04-02 0:34 ` [PATCH 2/2] selftests/mm: verify droppable mappings cannot be locked Anthony Yznaga
2026-04-02 7:28 ` David Hildenbrand (Arm)
2026-04-02 23:16 ` anthony.yznaga
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