mm/vmalloc.c: clean up map_vm_area third argument

Currently map_vm_area() takes (struct page *** pages) as third argument,
and after mapping, it moves (*pages) to point to (*pages +
nr_mappped_pages).

It looks like this kind of increment is useless to its caller these
days.  The callers don't care about the increments and actually they're
trying to avoid this by passing another copy to map_vm_area().

The caller can always guarantee all the pages can be mapped into vm_area
as specified in first argument and the caller only cares about whether
map_vm_area() fails or not.

This patch cleans up the pointer movement in map_vm_area() and updates
its callers accordingly.

Signed-off-by: WANG Chao <chaowang@redhat.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 5 deletions

diff --git a/drivers/lguest/core.c b/drivers/lguest/core.c
index 0bf1e4edf04d..6590558d1d31 100644
--- a/drivers/lguest/core.c
+++ b/drivers/lguest/core.c
@@ -42,7 +42,6 @@ DEFINE_MUTEX(lguest_lock);
 static __init int map_switcher(void)
 {
 	int i, err;
-	struct page **pagep;
 
 	/*
 	 * Map the Switcher in to high memory.
@@ -110,11 +109,9 @@ static __init int map_switcher(void)
 	 * This code actually sets up the pages we've allocated to appear at
 	 * switcher_addr.  map_vm_area() takes the vma we allocated above, the
 	 * kind of pages we're mapping (kernel pages), and a pointer to our
-	 * array of struct pages.  It increments that pointer, but we don't
-	 * care.
+	 * array of struct pages.
 	 */
-	pagep = lg_switcher_pages;
-	err = map_vm_area(switcher_vma, PAGE_KERNEL_EXEC, &pagep);
+	err = map_vm_area(switcher_vma, PAGE_KERNEL_EXEC, lg_switcher_pages);
 	if (err) {
 		printk("lguest: map_vm_area failed: %i\n", err);
 		goto free_vma;