is_vmalloc_addr(): Check if an address is within the vmalloc boundaries

Checking if an address is a vmalloc address is done in a couple of places.
Define a common version in mm.h and replace the other checks.

Again the include structures suck.  The definition of VMALLOC_START and
VMALLOC_END is not available in vmalloc.h since highmem.c cannot be included
there.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/net/cxgb3/cxgb3_offload.c

@@ -1070,9 +1070,7 @@ void *cxgb_alloc_mem(unsigned long size)
  */
 void cxgb_free_mem(void *addr)
 {
-	unsigned long p = (unsigned long)addr;
-
-	if (p >= VMALLOC_START && p < VMALLOC_END)
+	if (is_vmalloc_addr(addr))
 		vfree(addr);
 	else
 		kfree(addr);

fs/ntfs/malloc.h

@@ -85,8 +85,7 @@ static inline void *ntfs_malloc_nofs_nofail(unsigned long size)
 
 static inline void ntfs_free(void *addr)
 {
-	if (likely(((unsigned long)addr < VMALLOC_START) ||
-			((unsigned long)addr >= VMALLOC_END ))) {
+	if (!is_vmalloc_addr(addr)) {
 		kfree(addr);
 		/* free_page((unsigned long)addr); */
 		return;

fs/proc/kcore.c

@@ -325,7 +325,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
 		if (m == NULL) {
 			if (clear_user(buffer, tsz))
 				return -EFAULT;
-		} else if ((start >= VMALLOC_START) && (start < VMALLOC_END)) {
+		} else if (is_vmalloc_addr((void *)start)) {
 			char * elf_buf;
 			struct vm_struct *m;
 			unsigned long curstart = start;

fs/xfs/linux-2.6/kmem.c

@@ -92,8 +92,7 @@ kmem_zalloc_greedy(size_t *size, size_t minsize, size_t maxsize,
 void
 kmem_free(void *ptr, size_t size)
 {
-	if (((unsigned long)ptr < VMALLOC_START) ||
-	    ((unsigned long)ptr >= VMALLOC_END)) {
+	if (!is_vmalloc_addr(ptr)) {
 		kfree(ptr);
 	} else {
 		vfree(ptr);

fs/xfs/linux-2.6/xfs_buf.c

@@ -709,8 +709,7 @@ static inline struct page *
 mem_to_page(
 	void			*addr)
 {
-	if (((unsigned long)addr < VMALLOC_START) ||
-	    ((unsigned long)addr >= VMALLOC_END)) {
+	if ((!is_vmalloc_addr(addr))) {
 		return virt_to_page(addr);
 	} else {
 		return vmalloc_to_page(addr);

include/linux/mm.h

@@ -235,6 +235,14 @@ static inline int get_page_unless_zero(struct page *page)
 struct page *vmalloc_to_page(const void *addr);
 unsigned long vmalloc_to_pfn(const void *addr);
 
+/* Determine if an address is within the vmalloc range */
+static inline int is_vmalloc_addr(const void *x)
+{
+	unsigned long addr = (unsigned long)x;
+
+	return addr >= VMALLOC_START && addr < VMALLOC_END;
+}
+
 static inline struct page *compound_head(struct page *page)
 {
 	if (unlikely(PageTail(page)))

mm/sparse.c

@@ -353,17 +353,9 @@ static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
 	return __kmalloc_section_memmap(nr_pages);
 }
 
-static int vaddr_in_vmalloc_area(void *addr)
-{
-	if (addr >= (void *)VMALLOC_START &&
-	    addr < (void *)VMALLOC_END)
-		return 1;
-	return 0;
-}
-
 static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages)
 {
-	if (vaddr_in_vmalloc_area(memmap))
+	if (is_vmalloc_addr(memmap))
 		vfree(memmap);
 	else
 		free_pages((unsigned long)memmap,