mm: unify module_alloc code for vmalloc

Four architectures (arm, mips, sparc, x86) use __vmalloc_area() for
module_init().  Much of the code is duplicated and can be generalized in a
globally accessible function, __vmalloc_node_range().

__vmalloc_node() now calls into __vmalloc_node_range() with a range of
[VMALLOC_START, VMALLOC_END) for functionally equivalent behavior.

Each architecture may then use __vmalloc_node_range() directly to remove
the duplication of code.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index f675466..284346e 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1530,17 +1530,47 @@
 	return NULL;
 }
 
-void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot)
+/**
+ *	__vmalloc_node_range  -  allocate virtually contiguous memory
+ *	@size:		allocation size
+ *	@align:		desired alignment
+ *	@start:		vm area range start
+ *	@end:		vm area range end
+ *	@gfp_mask:	flags for the page level allocator
+ *	@prot:		protection mask for the allocated pages
+ *	@node:		node to use for allocation or -1
+ *	@caller:	caller's return address
+ *
+ *	Allocate enough pages to cover @size from the page level
+ *	allocator with @gfp_mask flags.  Map them into contiguous
+ *	kernel virtual space, using a pagetable protection of @prot.
+ */
+void *__vmalloc_node_range(unsigned long size, unsigned long align,
+			unsigned long start, unsigned long end, gfp_t gfp_mask,
+			pgprot_t prot, int node, void *caller)
 {
-	void *addr = __vmalloc_area_node(area, gfp_mask, prot, -1,
-					 __builtin_return_address(0));
+	struct vm_struct *area;
+	void *addr;
+	unsigned long real_size = size;
+
+	size = PAGE_ALIGN(size);
+	if (!size || (size >> PAGE_SHIFT) > totalram_pages)
+		return NULL;
+
+	area = __get_vm_area_node(size, align, VM_ALLOC, start, end, node,
+				  gfp_mask, caller);
+
+	if (!area)
+		return NULL;
+
+	addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
 
 	/*
 	 * A ref_count = 3 is needed because the vm_struct and vmap_area
 	 * structures allocated in the __get_vm_area_node() function contain
 	 * references to the virtual address of the vmalloc'ed block.
 	 */
-	kmemleak_alloc(addr, area->size - PAGE_SIZE, 3, gfp_mask);
+	kmemleak_alloc(addr, real_size, 3, gfp_mask);
 
 	return addr;
 }
@@ -1562,30 +1592,8 @@
 			    gfp_t gfp_mask, pgprot_t prot,
 			    int node, void *caller)
 {
-	struct vm_struct *area;
-	void *addr;
-	unsigned long real_size = size;
-
-	size = PAGE_ALIGN(size);
-	if (!size || (size >> PAGE_SHIFT) > totalram_pages)
-		return NULL;
-
-	area = __get_vm_area_node(size, align, VM_ALLOC, VMALLOC_START,
-				  VMALLOC_END, node, gfp_mask, caller);
-
-	if (!area)
-		return NULL;
-
-	addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
-
-	/*
-	 * A ref_count = 3 is needed because the vm_struct and vmap_area
-	 * structures allocated in the __get_vm_area_node() function contain
-	 * references to the virtual address of the vmalloc'ed block.
-	 */
-	kmemleak_alloc(addr, real_size, 3, gfp_mask);
-
-	return addr;
+	return __vmalloc_node_range(size, align, VMALLOC_START, VMALLOC_END,
+				gfp_mask, prot, node, caller);
 }
 
 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)