From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 7A9033AAF5F; Sat, 3 Oct 2026 17:56:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791050211; cv=none; b=jM4mU/h7UXHYrQuesBSj11SIWIiCiFvo+v6NYVbcKYtkEYda60t+LmKTLDkUb+lyWAMLRyfM+FcrRIzBuq1UZ2WxHRp+/tyQrqkOj0zl6PuC2SArNTRZz3eD9bWmswo+PS1RDCYHULG6LL2DLa7Hzeu8VwhS42A92VWbldGXwQA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791050211; c=relaxed/simple; bh=RYdqFs86tT71ewTmb4rZyWnUGDIEu2rWKZQtH7+F13Y=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=FMdICr7QOqjHPsNkzaFqjYgp00649DTiaS2ktmBQ/LdiCC21IGJEPwj4NB+m+Z2xlhWjnJ2LoiENxw8JfUc4ozTztoT8YwSkLdGHsuh0QLZKFH+ft/8V1ouXVAGhkTWCwWYJDS3STJJ0YOBx7B+wRA5w+w8uG/1FPoxX7AGdjGM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=byV1soFd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="byV1soFd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 075EB1F0089C; Sat, 3 Oct 2026 17:56:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791050204; bh=RYdqFs86tT71ewTmb4rZyWnUGDIEu2rWKZQtH7+F13Y=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=byV1soFdeo+3Eu4FFFjYLc3DDrzMkuvXdQv66VoS4PIe5WYo5djLQBLrRA4EyXdP7 OUt6dC77pKTctff3rtjz9LUIosJdZriTnRgVTMDFK12wbznTcENGcmjYAHVt8AfIYC 28hAk2SosnN+kKBvlvr7tWFj/Fjtwtm9bxmc45HCIfP6D160S8seAvLBJ0FMGRE/EN oJkD6lwkui+8kfpllwpmJv7WyDNV6n7gMg+mva0Trs69dqdBGn/aD6+rpApfQd82ov l1jV6WRsG2Wrafrp0JKXRoDtEaq2Q2x1gBXs0AOSsBEWjCVts2+Lm22tyiyP0dkYJz a8d2nprs/hfvg== From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 01/38] mm/vma: fix mmap_prepare file handling, remove file_doesnt_need_get Reply-To: sashiko-reviews@lists.linux.dev To: =?utf-8?b?TG9yZW56byBTdG9ha2VzIChBUk0p?= Cc: kvmarm@lists.linux.dev, linux-trace-kernel@vger.kernel.org, kvm@vger.kernel.org, "Vasily Gorbik" , selinux@vger.kernel.org, dri-devel@lists.freedesktop.org, "Heiko Carstens" , linux-s390@vger.kernel.org, "Alexander Gordeev" , "Oliver Upton" , linux-rdma@vger.kernel.org, linux-perf-users@vger.kernel.org, "Christian Borntraeger" , "Marc Zyngier" , bpf@vger.kernel.org, linux-scsi@vger.kernel.org In-Reply-To: <20261003-b4-mmap-prepare-vma-flag-sanify-v4-1-a1f052500fd7@kernel.org> References: <20261003-b4-mmap-prepare-vma-flag-sanify-v4-0-a1f052500fd7@kernel.org> <20261003-b4-mmap-prepare-vma-flag-sanify-v4-1-a1f052500fd7@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sat, 03 Oct 2026 17:56:43 +0000 Message-Id: <20261003175644.075EB1F0089C@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > The map->file_doesnt_need_get flag is confusing and the existing > implementation has holes. >=20 > Drivers are permitted to change the owning file of a mapping. If they do > so, they are required to take a reference on that file. >=20 > The mmap() operation which ultimately invokes __mmap_region() is guarante= ed > to drop the refcount for the original file the mapping was made under, but > this is not true for the replaced file. >=20 > This has been addressed so far by tracking map->file_doesnt_need_get, whi= ch > is rather poorly named and unfortunately fails to correctly track whether > or not an additional put were needed in a number of cases. >=20 > Make life easier by removing this flag, and instead drop the reference for > [ ... ] > No in-tree driver is impacted by the incorrect implementation of this > currently (no driver that does this is mergeable for one), so this does n= ot > need to be a fix. >=20 > Signed-off-by: Lorenzo Stoakes (ARM) Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261003-b4-mmap-pr= epare-vma-flag-sanify-v4-0-a1f052500fd7@kernel.org?part=3D1