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 C303B1EFF8D; Fri, 12 Jun 2026 14:09:23 +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=1781273364; cv=none; b=ozLEObtynY8QDRcnPskXvZw520PlDMMlJiSBAnqIjZjC8tVxWUO166o/+35INe7D+R+Sw6qDahIfhSBpWqRn+a5inEQMKxW5rO9FDz33pThccm6mP5wyPuNlgswQ/tjEitxVp3j+W7gSjdruIKHceJjrJrS97NOUw3WABhuiuME= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781273364; c=relaxed/simple; bh=C369Q5NFIci2y7Q9cRjAey1W03hL7nn4gHCLy71oMtA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CSuOZZCLVF9QPsxCWFSVVJP+4xsD9x5hodAkbO0pDfDSAI9+f08UBkjVdAkl9hFaLKhpRoIyQ8niWJJngZea+mxJmXVHt2GLVaojt3SL8a5kBPgxImweyKmGtTQxPz+oF0shMxNtQ8AzUUxmu3/0GIL2RY5NWancgt/WG2K3KEA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bBsjm5z2; 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="bBsjm5z2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 18AFC1F000E9; Fri, 12 Jun 2026 14:09:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781273363; bh=TLdV27eWe8bzH9uTpJ3I7eStVmUcSjphmin8eMb7h7k=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=bBsjm5z2YMEwh2gXpTAKz1lQujYcB6slsLx0pXhOaWHKuVZWfe/GgjLDVZHrxdh5u cHQ/J3ApOSMFQ6EFhLGQWszwgQkYFOmhn+5nU2mB40O8sU5JMGXJ6k3fp2HWyiSZiZ nNvcCzO+/GimKw6mzpjQLdMd+xZRbMv6VYio5LLlIapb4dO1vnChun/6ibAiur40N5 M3u+Ivyqwsi5b+DEUMQ1S+8I0jh+ZsTbOATU3hde2W2PjVhyA1Df1V/TO4AZcDFDSC U4cEh6LWAGzHpBKmCW25ih5CYJlD1x1AtVhTFsWBlAZXm6GU4tYIKpdO/jDvars0yW VMCDjx4ddpsnA== Message-ID: Date: Fri, 12 Jun 2026 16:09:18 +0200 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 v2 1/5] mm: Make per-VMA locks available universally Content-Language: en-US To: Suren Baghdasaryan , Dave Hansen Cc: linux-kernel@vger.kernel.org, Alice Ryhl , Andrew Morton , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOl?= =?UTF-8?Q?g?= , Carlos Llamas , Christian Brauner , David Ahern , "David S. Miller" , Greg Kroah-Hartman , "Liam R. Howlett" , linux-mm@kvack.org, Lorenzo Stoakes , netdev@vger.kernel.org, Shakeel Butt , Todd Kjos References: <20260610230409.A44D29FA@davehans-spike.ostc.intel.com> <20260610230411.617DD5E7@davehans-spike.ostc.intel.com> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSNWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBrZXJuZWwub3JnPsLBsAQTAQoAWhYhBKlA1DSZLC6OmRA9UCJPp+fM gqZkBQJqFFy6GxSAAAAAAAQADm1hbnUyLDIuNSsxLjEyLDIsMgIbAwUJGtCBUAULCQgHAwUV CgkICwUWAgMBAAIeBQIXgAAKCRAiT6fnzIKmZJIUEADFx/tREzUImHrEwVHeSvDFmA7tJysI UVrlvrM09E7GIuzphzv7jYmo8n3ANpCczLEVr4G0syYQdTigaZgv3+FQDIIzhKih1IHhu1Ei XHlywNWKnQxxQEUNi5Mwx43wQz5XVw9F1A7gtKBKNtfogO511hAbrzagrYajyQacEJ/+sfhZ 9Da8ltHIXD8pcYaHUfQgEusCgmEd9+KrUwrTbckFKmYq5chuE6yJ4J0EmWknL096jIE6CnzF FRslQ3B1UKDjxVsm1ZHfir5NeWszLkTvGFsddFaWTgh8UycESG6VQzKXjjewXu2pG7YQYRpj QKm1W5X2TkwWkXRBZTmfmbhxIUMh3+zf5wQ463rSmDN/8v81tdqBtAW6rH/kzg1GvkaTHXn0 507yEHFzBksk2viAuIxxr7km8+/KARYLIdGtx30EG8cKzAUZOK6WqxtNCsXUJNrVE8CWrCaD icoNu7Fs1c5hmPHdSTnU48ce67449DdnO4neLSNhRiGlMHJgfJUmgrxu/hcYeOZ3haWmEQ2w uW1Mh01OHi8QZHCEyAbABrPs9GUgccc/4eYXX9hIgxfSkYzn8f+8NuIFPWl/0uTvjgqU29FQ SbzOLxHq9439Ox40G5mS5eZXRGxITYR+6TXvRGI6P/264jvflnr/pDGUttaikU+0W+1uxgKH cmYbEc7ATQRbGTU1AQgAn0H6UrFiWcovkh6EXVcl+SeqyO6JHOPm+e9Wu0Vw+VIUvXZVUVVQ La1PQDUi6j00ChlcR66g9/V0sPIcSutacPKfdKYOBvzd4rlhL8rfrdEsQw5ApZxrA8kYZVMh FmBRKAa6wos25moTlMKpCWzTH84+WO5+ziCTsTUZASAToz3RdunTD+vQcHj0GqNTPAHK63sf bAB2I0BslZkXkY1RLb/YhuA6E7JyEd2pilZOrIuBGl/5q2qSakgnAVFWFBR/DO27JuAksYnq +aH8vI0xGvwn75KqSk4UzAkDzWSmO4ZHuahKtQgZNsMYV+PGayRBX9b9zbldzopoLBdqHc4n jQARAQABwsF8BBgBCgAmAhsMFiEEqUDUNJksLo6ZED1QIk+n58yCpmQFAmfIHFQFCRYU6J8A CgkQIk+n58yCpmS2PA//bqN1LfcotmArgElsa+0EGZSQlYgK48pm8WAeTXTngudP9IJ4SuKY HR5RNjHcBeqN+Me0zxRqYzRb8nGanHEkDyf4Im8DQM8d6vbyU+FcPmG4skud4kgS1zMHnlVd SXfSIwKC/hKgdHG8aBV7545Lz9X6Iohea+94wneD0aw/hqF+QWewGZhWJriWAZtvEkzNjQOi 4U9F/trLten/x7bpphDSnDMKJtITbtzATT1Dq7o7VpIUK1nCTQALMuMjKCdi8OdU/+V+R3O4 0PXWvX8qrvqYapVbZ+9KqT74FsuB0Ya9uXwgBF2Q6cRuETZk5vqaqKxzqoQZCO8AOz/58j6O 2RHNy/mZEN+7tJ5Tsq42zVJ4jxsT8b9YplavCMsnBgDeRWhcbYhCyttoL7nYISyWg4kQYZ/P wIV3OuNv2f8iKYsxNsRuClOAF82+gvqOy1/1pprFjy8uo2pkoOrb63aOP3vO5VHnRKgra6dq NcaZ+c6J4H+nEJGi2SkHAUJz5oBzuThvPudLvPA/SK8sKoM01IRxSihev/S/5WLazXB1PGem OCbvzC1IjWJJraxiDJ5IygokapUa2RP7+WBR22skQ3SSl6G107QgWKSyTOGWEaRmV53vxQLV jXuCmzSSasTL60zq5yGrT4/DYQVSNEUiUbG4pYekxJujNeEDkUlky0Y= In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/11/26 21:29, Suren Baghdasaryan wrote: >> - >> -/* >> - * At least xtensa ends up having protection faults even with no >> - * MMU.. No stack expansion, at least. >> - */ >> -struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm, >> - unsigned long addr, struct pt_regs *regs) >> -{ >> - struct vm_area_struct *vma; >> - >> - mmap_read_lock(mm); >> - vma = vma_lookup(mm, addr); >> - if (!vma) >> - mmap_read_unlock(mm); >> - return vma; >> -} > > Might this removal break CONFIG_MMU=n && CONFIG_LOCK_MM_AND_FIND_VMA=n case? Seems to me only the architectures that select CONFIG_LOCK_MM_AND_FIND_VMA also call lock_mm_and_find_vma(). So it's probably fine? I think this fallback was only for architectures that select CONFIG_LOCK_MM_AND_FIND_VMA *and* have CONFIG_MMU=n (variant). It just wasn't guarded by #ifdef CONFIG_LOCK_MM_AND_FIND_VMA as well. >> - >> -#endif /* CONFIG_MMU */ >> diff -puN mm/pagewalk.c~unconditional-vma-locks mm/pagewalk.c