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Date: Sun, 21 Jan 2018 23:39:43 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: starvik@axis.com, jesper.nilsson@axis.com, akpm@linux-foundation.org,
        linux-cris-kernel@axis.com, linux-kernel@vger.kernel.org,
        Davidlohr Bueso <dbueso@suse.de>
Subject: Re: [PATCH] arch/cris: use get_user_pages_fast()
Message-ID: <20180121233943.GO13338@ZenIV.linux.org.uk>
References: <20180121225929.11782-1-dave@stgolabs.net>
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On Sun, Jan 21, 2018 at 02:59:29PM -0800, Davidlohr Bueso wrote:
> Since we currently hold mmap_sem across both gup calls (and
> nothing more), we can substitute it with two _fast()
> alternatives and possibly avoid grabbing the lock.
> 
> This was found while adding mmap_sem wrappers, and was also
> previously reported by Al: https://lkml.org/lkml/2017/11/17/777

See commit 9a949e8ff92246c0753b2805c2a001cb991fffe5
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Sat Nov 18 14:37:46 2017 -0500

    cris: switch to get_user_pages_fast()
    
    no point holding ->mmap_sem over both calls.
    
    Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>


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