Commit f8dbf0a7 authored by Huang Shijie's avatar Huang Shijie Committed by Linus Torvalds

mmap: save some cycles for the shared anonymous mapping

shmem_zero_setup() does not change vm_start, pgoff or vm_flags, only some
drivers change them (such as /driver/video/bfin-t350mcqb-fb.c).

Move these codes to a more proper place to save cycles for shared
anonymous mapping.
Signed-off-by: default avatarHuang Shijie <shijie8@gmail.com>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Acked-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 252c5f94
......@@ -1191,21 +1191,21 @@ munmap_back:
goto unmap_and_free_vma;
if (vm_flags & VM_EXECUTABLE)
added_exe_file_vma(mm);
/* Can addr have changed??
*
* Answer: Yes, several device drivers can do it in their
* f_op->mmap method. -DaveM
*/
addr = vma->vm_start;
pgoff = vma->vm_pgoff;
vm_flags = vma->vm_flags;
} else if (vm_flags & VM_SHARED) {
error = shmem_zero_setup(vma);
if (error)
goto free_vma;
}
/* Can addr have changed??
*
* Answer: Yes, several device drivers can do it in their
* f_op->mmap method. -DaveM
*/
addr = vma->vm_start;
pgoff = vma->vm_pgoff;
vm_flags = vma->vm_flags;
if (vma_wants_writenotify(vma))
vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
......
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