VM: add "vm_mmap()" helper function
This continues the theme started with vm_brk() and vm_munmap():
vm_mmap() does the same thing as do_mmap(), but additionally does the
required VM locking.
This uninlines (and rewrites it to be clearer) do_mmap(), which sadly
duplicates it in mm/mmap.c and mm/nommu.c. But that way we don't have
to export our internal do_mmap_pgoff() function.
Some day we hopefully don't have to export do_mmap() either, if all
modular users can become the simpler vm_mmap() instead. We're actually
very close to that already, with the notable exception of the (broken)
use in i810, and a couple of stragglers in binfmt_elf.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c
index 26d5197..392ce71 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_gem.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c
@@ -581,10 +581,8 @@
obj->filp->f_op = &exynos_drm_gem_fops;
obj->filp->private_data = obj;
- down_write(¤t->mm->mmap_sem);
- addr = do_mmap(obj->filp, 0, args->size,
+ addr = vm_mmap(obj->filp, 0, args->size,
PROT_READ | PROT_WRITE, MAP_SHARED, 0);
- up_write(¤t->mm->mmap_sem);
drm_gem_object_unreference_unlocked(obj);