Re: [PATCH] mm/mmap.c: use while instead of if+goto

From: Andrew Morton
Date: Mon Mar 30 2015 - 17:58:33 EST


On Mon, 30 Mar 2015 23:54:13 +0300 "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx> wrote:

> On Mon, Mar 30, 2015 at 09:40:35PM +0200, Rasmus Villemoes wrote:
> > The creators of the C language gave us the while keyword. Let's use
> > that instead of synthesizing it from if+goto.
> >
> > Made possible by 6597d783397a ("mm/mmap.c: replace find_vma_prepare()
> > with clearer find_vma_links()").
> >
> > Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
>
>
> Looks good, except both your plus-lines are over 80-characters long for no
> reason.

--- a/mm/mmap.c~mm-mmapc-use-while-instead-of-ifgoto-fix
+++ a/mm/mmap.c
@@ -1551,7 +1551,8 @@ unsigned long mmap_region(struct file *f

/* Clear old maps */
error = -ENOMEM;
- while (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
+ while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
+ &rb_parent)) {
if (do_munmap(mm, addr, len))
return -ENOMEM;
}
@@ -1569,7 +1570,8 @@ unsigned long mmap_region(struct file *f
/*
* Can we just expand an old mapping?
*/
- vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
+ vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff,
+ NULL);
if (vma)
goto out;

@@ -2737,7 +2739,8 @@ static unsigned long do_brk(unsigned lon
/*
* Clear old maps. this also does some error checking for us
*/
- while (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) {
+ while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,
+ &rb_parent)) {
if (do_munmap(mm, addr, len))
return -ENOMEM;
}

I'm not sure it improves things a lot, but mmap.c has been pretty
careful about the 80-col thing...

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