Messages in this thread |  | | Date | Mon, 8 Jun 2015 10:17:51 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH] mm/mmap.c: optimization of do_mmap_pgoff function |
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On Sat 06-06-15 11:54:32, Piotr Kwapulinski wrote: > The simple check for zero length memory mapping may be performed > earlier. It causes that in case of zero length memory mapping some > unnecessary code is not executed at all. It does not make the code less > readable and saves some CPU cycles. > > Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
> --- > mm/mmap.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index bb50cac..aa632ad 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -1258,6 +1258,9 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, > > *populate = 0; > > + if (!len) > + return -EINVAL; > + > /* > * Does the application expect PROT_READ to imply PROT_EXEC? > * > @@ -1268,9 +1271,6 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, > if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC))) > prot |= PROT_EXEC; > > - if (!len) > - return -EINVAL; > - > if (!(flags & MAP_FIXED)) > addr = round_hint_to_min(addr); > > -- > 2.3.7 >
-- Michal Hocko SUSE Labs
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