* [PATCH] mm/mmap.c: use while instead of if+goto
@ 2015-03-30 19:40 Rasmus Villemoes
2015-03-30 20:54 ` Kirill A. Shutemov
0 siblings, 1 reply; 4+ messages in thread
From: Rasmus Villemoes @ 2015-03-30 19:40 UTC (permalink / raw)
To: Andrew Morton, Kirill A. Shutemov, Sasha Levin, Cyrill Gorcunov,
Roman Gushchin
Cc: Hugh Dickins, Rasmus Villemoes, linux-mm, linux-kernel
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@rasmusvillemoes.dk>
---
mm/mmap.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index da9990acc08b..e1ae629b1e9c 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1553,11 +1553,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
/* Clear old maps */
error = -ENOMEM;
-munmap_back:
- if (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;
- goto munmap_back;
}
/*
@@ -2741,11 +2739,9 @@ static unsigned long do_brk(unsigned long addr, unsigned long len)
/*
* Clear old maps. this also does some error checking for us
*/
- munmap_back:
- if (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;
- goto munmap_back;
}
/* Check against address space limits *after* clearing old maps... */
--
2.1.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] mm/mmap.c: use while instead of if+goto
2015-03-30 19:40 [PATCH] mm/mmap.c: use while instead of if+goto Rasmus Villemoes
@ 2015-03-30 20:54 ` Kirill A. Shutemov
2015-03-30 21:58 ` Andrew Morton
0 siblings, 1 reply; 4+ messages in thread
From: Kirill A. Shutemov @ 2015-03-30 20:54 UTC (permalink / raw)
To: Rasmus Villemoes
Cc: Andrew Morton, Kirill A. Shutemov, Sasha Levin, Cyrill Gorcunov,
Roman Gushchin, Hugh Dickins, linux-mm, linux-kernel
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@rasmusvillemoes.dk>
Looks good, except both your plus-lines are over 80-characters long for no
reason.
> ---
> mm/mmap.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index da9990acc08b..e1ae629b1e9c 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1553,11 +1553,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
>
> /* Clear old maps */
> error = -ENOMEM;
> -munmap_back:
> - if (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;
> - goto munmap_back;
> }
>
> /*
> @@ -2741,11 +2739,9 @@ static unsigned long do_brk(unsigned long addr, unsigned long len)
> /*
> * Clear old maps. this also does some error checking for us
> */
> - munmap_back:
> - if (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;
> - goto munmap_back;
> }
>
> /* Check against address space limits *after* clearing old maps... */
--
Kirill A. Shutemov
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mm/mmap.c: use while instead of if+goto
2015-03-30 20:54 ` Kirill A. Shutemov
@ 2015-03-30 21:58 ` Andrew Morton
2015-03-31 10:01 ` Rasmus Villemoes
0 siblings, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2015-03-30 21:58 UTC (permalink / raw)
To: Kirill A. Shutemov
Cc: Rasmus Villemoes, Kirill A. Shutemov, Sasha Levin,
Cyrill Gorcunov, Roman Gushchin, Hugh Dickins, linux-mm,
linux-kernel
On Mon, 30 Mar 2015 23:54:13 +0300 "Kirill A. Shutemov" <kirill@shutemov.name> 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@rasmusvillemoes.dk>
>
>
> 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...
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] mm/mmap.c: use while instead of if+goto
2015-03-30 21:58 ` Andrew Morton
@ 2015-03-31 10:01 ` Rasmus Villemoes
0 siblings, 0 replies; 4+ messages in thread
From: Rasmus Villemoes @ 2015-03-31 10:01 UTC (permalink / raw)
To: Andrew Morton
Cc: Kirill A. Shutemov, Kirill A. Shutemov, Sasha Levin,
Cyrill Gorcunov, Roman Gushchin, Hugh Dickins, linux-mm,
linux-kernel
On Mon, Mar 30 2015, Andrew Morton <akpm@linux-foundation.org> wrote:
> On Mon, 30 Mar 2015 23:54:13 +0300 "Kirill A. Shutemov" <kirill@shutemov.name> 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@rasmusvillemoes.dk>
>>
>>
>> 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
>
> I'm not sure it improves things a lot, but mmap.c has been pretty
> careful about the 80-col thing...
Yeah, I did run checkpatch and chose to ignore the 80-col warning, since
I think both the patch and the resulting code was more readable that
way. I don't really care either way, though.
Rasmus
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2015-03-31 10:01 UTC | newest]
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2015-03-30 19:40 [PATCH] mm/mmap.c: use while instead of if+goto Rasmus Villemoes
2015-03-30 20:54 ` Kirill A. Shutemov
2015-03-30 21:58 ` Andrew Morton
2015-03-31 10:01 ` Rasmus Villemoes
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