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From: Jan Kara <jack@suse.cz>
To: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Jan Kara <jack@suse.cz>, Hugh Dickins <hughd@google.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Rik van Riel <riel@redhat.com>, linux-mm <linux-mm@kvack.org>,
	Mel Gorman <mgorman@techsingularity.net>,
	tbsaunde@tbsaunde.org, robert@ocallahan.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing
Date: Mon, 10 Oct 2016 18:37:57 +0200	[thread overview]
Message-ID: <20161010163757.GF24081@quack2.suse.cz> (raw)
In-Reply-To: <20161010082828.GA13595@lucifer>

On Mon 10-10-16 09:28:28, Lorenzo Stoakes wrote:
> On Mon, Oct 10, 2016 at 09:47:12AM +0200, Jan Kara wrote:
> > Yeah, so my cleanups where mostly concerned about mmap_sem locking and
> > reducing number of places which cared about those. Regarding flags for
> > get_user_pages() / get_vaddr_frames(), I agree that using flags argument
> > as Linus suggests will make it easier to see what the callers actually
> > want. So I'm for that.
> 
> Great, thanks Jan! I have a draft patch that needs a little tweaking/further
> testing but isn't too far off.
> 
> One thing I am wondering about is whether functions that have write/force
> parameters replaced with gup_flags should mask against (FOLL_WRITE | FOLL_FORCE)
> to prevent callers from doing unexpected things with other FOLL_* flags?
> 
> I'm inclined _not_ to because it adds a rather non-obvious restriction on this
> parameter, reduces clarity about which flags are actually being used (which is
> the point of the patch in the first place), and the caller ought to know what
> they are doing.

Yeah, just leave flags as is. There is no strong reason to restrict them.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

WARNING: multiple messages have this Message-ID (diff)
From: Jan Kara <jack@suse.cz>
To: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Jan Kara <jack@suse.cz>, Hugh Dickins <hughd@google.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Rik van Riel <riel@redhat.com>, linux-mm <linux-mm@kvack.org>,
	Mel Gorman <mgorman@techsingularity.net>,
	tbsaunde@tbsaunde.org, robert@ocallahan.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing
Date: Mon, 10 Oct 2016 18:37:57 +0200	[thread overview]
Message-ID: <20161010163757.GF24081@quack2.suse.cz> (raw)
In-Reply-To: <20161010082828.GA13595@lucifer>

On Mon 10-10-16 09:28:28, Lorenzo Stoakes wrote:
> On Mon, Oct 10, 2016 at 09:47:12AM +0200, Jan Kara wrote:
> > Yeah, so my cleanups where mostly concerned about mmap_sem locking and
> > reducing number of places which cared about those. Regarding flags for
> > get_user_pages() / get_vaddr_frames(), I agree that using flags argument
> > as Linus suggests will make it easier to see what the callers actually
> > want. So I'm for that.
> 
> Great, thanks Jan! I have a draft patch that needs a little tweaking/further
> testing but isn't too far off.
> 
> One thing I am wondering about is whether functions that have write/force
> parameters replaced with gup_flags should mask against (FOLL_WRITE | FOLL_FORCE)
> to prevent callers from doing unexpected things with other FOLL_* flags?
> 
> I'm inclined _not_ to because it adds a rather non-obvious restriction on this
> parameter, reduces clarity about which flags are actually being used (which is
> the point of the patch in the first place), and the caller ought to know what
> they are doing.

Yeah, just leave flags as is. There is no strong reason to restrict them.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

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  reply	other threads:[~2016-10-10 16:38 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-11 22:54 [PATCH] mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing Lorenzo Stoakes
2016-09-11 22:59 ` Lorenzo Stoakes
2016-09-11 22:59   ` Lorenzo Stoakes
2016-09-25 18:47 ` Lorenzo Stoakes
2016-09-25 18:47   ` Lorenzo Stoakes
2016-09-25 20:52   ` Linus Torvalds
2016-09-25 20:52     ` Linus Torvalds
2016-09-25 22:24     ` Linus Torvalds
2016-09-25 22:24       ` Linus Torvalds
2016-09-25 22:34     ` Rik van Riel
2016-09-25 22:50       ` Linus Torvalds
2016-09-25 22:50         ` Linus Torvalds
2016-09-25 23:28         ` Hugh Dickins
2016-09-25 23:28           ` Hugh Dickins
2016-09-26  0:49         ` Rik van Riel
2016-09-26  1:05           ` Linus Torvalds
2016-09-26  1:05             ` Linus Torvalds
2016-10-07 10:07         ` Lorenzo Stoakes
2016-10-07 10:07           ` Lorenzo Stoakes
2016-10-07 15:34           ` Linus Torvalds
2016-10-07 15:34             ` Linus Torvalds
2016-10-07 16:22             ` Lorenzo Stoakes
2016-10-07 16:22               ` Lorenzo Stoakes
2016-10-07 18:16               ` Hugh Dickins
2016-10-07 18:16                 ` Hugh Dickins
2016-10-07 18:26                 ` Lorenzo Stoakes
2016-10-07 18:26                   ` Lorenzo Stoakes
2016-10-10  7:47                 ` Jan Kara
2016-10-10  7:47                   ` Jan Kara
2016-10-10  8:28                   ` Lorenzo Stoakes
2016-10-10  8:28                     ` Lorenzo Stoakes
2016-10-10 16:37                     ` Jan Kara [this message]
2016-10-10 16:37                       ` Jan Kara
2016-09-26  8:19 ` Mel Gorman

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