[PATCH 2/3] vmalloc: use ZERO_SIZE_PTR / ZERO_OR_NULL_PTR

[Dmitry Antipov]

 - Fix vmap() to return ZERO_SIZE_PTR if 0 pages are requested;
 - fix __vmalloc_node_range() to return ZERO_SIZE_PTR if 0 bytes
   are requested;
 - fix __vunmap() to check passed pointer with ZERO_OR_NULL_PTR.

Signed-off-by: Dmitry Antipov <dmitry.antipov@xxxxxxxxxx>
---
 mm/vmalloc.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 86ce9a5..040a9cd 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1456,7 +1456,7 @@ static void __vunmap(const void *addr, int deallocate_pages)
 {
 	struct vm_struct *area;
 
-	if (!addr)
+	if (unlikely(ZERO_OR_NULL_PTR(addr)))
 		return;
 
 	if ((PAGE_SIZE-1) & (unsigned long)addr) {
@@ -1548,7 +1548,9 @@ void *vmap(struct page **pages, unsigned int count,
 
 	might_sleep();
 
-	if (count > totalram_pages)
+	if (unlikely(!count))
+		return ZERO_SIZE_PTR;
+	if (unlikely(count > totalram_pages))
 		return NULL;
 
 	area = get_vm_area_caller((count << PAGE_SHIFT), flags,
@@ -1648,8 +1650,10 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
 	void *addr;
 	unsigned long real_size = size;
 
+	if (unlikely(!size))
+		return ZERO_SIZE_PTR;
 	size = PAGE_ALIGN(size);
-	if (!size || (size >> PAGE_SHIFT) > totalram_pages)
+	if (unlikely((size >> PAGE_SHIFT) > totalram_pages))
 		goto fail;
 
 	area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNLIST,
-- 
1.7.7.6

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