speed up madvise_need_mmap_write() usage

In the new madvise_need_mmap_write() call we can avoid an extra case
statement and function call as follows.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/mm/madvise.c b/mm/madvise.c
index 60542d006ec..93ee375b38e 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -287,9 +287,11 @@ asmlinkage long sys_madvise(unsigned long start, size_t len_in, int behavior)
         struct vm_area_struct * vma, *prev;
         int unmapped_error = 0;
         int error = -EINVAL;
+        int write;
         size_t len;
 
-        if (madvise_need_mmap_write(behavior))
+        write = madvise_need_mmap_write(behavior);
+        if (write)
                 down_write(&current->mm->mmap_sem);
         else
                 down_read(&current->mm->mmap_sem);
@@ -354,7 +356,7 @@ asmlinkage long sys_madvise(unsigned long start, size_t len_in, int behavior)
                         vma = find_vma(current->mm, start);
         }
 out:
-        if (madvise_need_mmap_write(behavior))
+        if (write)
                 up_write(&current->mm->mmap_sem);
         else
                 up_read(&current->mm->mmap_sem);