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, 5 insertions, 9 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 9ec4173f48a8..2b0aa5486092 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1270,19 +1270,15 @@ void unmap_kernel_range(unsigned long addr, unsigned long size)
 }
 EXPORT_SYMBOL_GPL(unmap_kernel_range);
 
-int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page ***pages)
+int map_vm_area(struct vm_struct *area, pgprot_t prot, struct page **pages)
 {
 	unsigned long addr = (unsigned long)area->addr;
 	unsigned long end = addr + get_vm_area_size(area);
 	int err;
 
-	err = vmap_page_range(addr, end, prot, *pages);
-	if (err > 0) {
-		*pages += err;
-		err = 0;
-	}
+	err = vmap_page_range(addr, end, prot, pages);
 
-	return err;
+	return err > 0 ? 0 : err;
 }
 EXPORT_SYMBOL_GPL(map_vm_area);
 
@@ -1548,7 +1544,7 @@ void *vmap(struct page **pages, unsigned int count,
 	if (!area)
 		return NULL;
 
-	if (map_vm_area(area, prot, &pages)) {
+	if (map_vm_area(area, prot, pages)) {
 		vunmap(area->addr);
 		return NULL;
 	}
@@ -1606,7 +1602,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 			cond_resched();
 	}
 
-	if (map_vm_area(area, prot, &pages))
+	if (map_vm_area(area, prot, pages))
 		goto fail;
 	return area->addr;