From mboxrd@z Thu Jan  1 00:00:00 1970
From: lstoakes@gmail.com (Lorenzo Stoakes)
Date: Tue, 18 Oct 2016 14:56:09 +0100
Subject: [PATCH 04/10] mm: replace get_user_pages_locked() write/force
 parameters with gup_flags
In-Reply-To: <20161018125425.GD29967@quack2.suse.cz>
References: <20161013002020.3062-1-lstoakes@gmail.com>
 <20161013002020.3062-5-lstoakes@gmail.com>
 <20161018125425.GD29967@quack2.suse.cz>
Message-ID: <20161018135609.GA30025@lucifer>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Oct 18, 2016 at 02:54:25PM +0200, Jan Kara wrote:
> > @@ -1282,7 +1282,7 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
> >  			    int write, int force, struct page **pages,
> >  			    struct vm_area_struct **vmas);
> >  long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
> > -		    int write, int force, struct page **pages, int *locked);
> > +		    unsigned int gup_flags, struct page **pages, int *locked);
>
> Hum, the prototype is inconsistent with e.g. __get_user_pages_unlocked()
> where gup_flags come after **pages argument. Actually it makes more sense
> to have it before **pages so that input arguments come first and output
> arguments second but I don't care that much. But it definitely should be
> consistent...

It was difficult to decide quite how to arrange parameters as there was
inconsitency with regards to parameter ordering already - for example
__get_user_pages() places its flags argument before pages whereas, as you note,
__get_user_pages_unlocked() puts them afterwards.

I ended up compromising by trying to match the existing ordering of the function
as much as I could by replacing write, force pairs with gup_flags in the same
location (with the exception of get_user_pages_unlocked() which I felt should
match __get_user_pages_unlocked() in signature) or if there was already a
gup_flags parameter as in the case of __get_user_pages_unlocked() I simply
removed the write, force pair and left the flags as the last parameter.

I am happy to rearrange parameters as needed, however I am not sure if it'd be
worthwhile for me to do so (I am keen to try to avoid adding too much noise here
:)

If we were to rearrange parameters for consistency I'd suggest adjusting
__get_user_pages_unlocked() to put gup_flags before pages and do the same with
get_user_pages_unlocked(), let me know what you think.