mm: add vzalloc() and vzalloc_node() helpers

Drop-in helper function backport from upstream.

Upstream commits:

  commit e1ca7788dec6773b1a2bce51b7141948f2b8bccf

  Author: Dave Young <hidave.darkstar@gmail.com>

  Date:   Tue Oct 26 14:22:06 2010 -0700

    mm: add vzalloc() and vzalloc_node() helpers

    Add vzalloc() and vzalloc_node() to encapsulate the

    vmalloc-then-memset-zero operation.

    Use __GFP_ZERO to zero fill the allocated memory.

    Signed-off-by: Dave Young <hidave.darkstar@gmail.com>

    Cc: Christoph Lameter <cl@linux-foundation.org>

    Acked-by: Greg Ungerer <gerg@snapgear.com>

    Cc: David Howells <dhowells@redhat.com>

    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

  commit 9a14f653dfe349c0916e6a78c413effa2fa3f001

  Author: Paul Mundt <lethal@linux-sh.org>

  Date:   Fri Dec 24 11:50:34 2010 +0900

    nommu: Fix up vmalloc_node() symbol export regression.

    Commit e1ca778 ("mm: add vzalloc() and vzalloc_node() helpers") ended up

    accidentally deleting the vmalloc_node() symbol export, resulting in:

    "vmalloc_node" [net/core/pktgen.ko] undefined!

    "vmalloc_node" [net/netfilter/x_tables.ko] undefined!

    regressions.

    Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Signed-off-by: Jarod Wilson <jarod@redhat.com>

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h

index d9a787a..5e03b00 100644

--- a/include/linux/vmalloc.h

+++ b/include/linux/vmalloc.h

@@ -51,8 +51,10 @@ static inline void vmalloc_init(void)

 #endif

 extern void *vmalloc(unsigned long size);

+extern void *vzalloc(unsigned long size);

 extern void *vmalloc_user(unsigned long size);

 extern void *vmalloc_node(unsigned long size, int node);

+extern void *vzalloc_node(unsigned long size, int node);

 extern void *vmalloc_exec(unsigned long size);

 extern void *vmalloc_32(unsigned long size);

 extern void *vmalloc_32_user(unsigned long size);

diff --git a/mm/nommu.c b/mm/nommu.c

index b30fde0..bdb4d22 100644

--- a/mm/nommu.c

+++ b/mm/nommu.c

@@ -298,12 +298,60 @@ void *vmalloc(unsigned long size)

 }

 EXPORT_SYMBOL(vmalloc);

+/*

+ *	vzalloc - allocate virtually continguos memory with zero fill

+ *

+ *	@size:		allocation size

+ *

+ *	Allocate enough pages to cover @size from the page level

+ *	allocator and map them into continguos kernel virtual space.

+ *	The memory allocated is set to zero.

+ *

+ *	For tight control over page level allocator and protection flags

+ *	use __vmalloc() instead.

+ */

+void *vzalloc(unsigned long size)

+{

+	return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,

+			PAGE_KERNEL);

+}

+EXPORT_SYMBOL(vzalloc);

+

+/**

+ * vmalloc_node - allocate memory on a specific node

+ * @size:	allocation size

+ * @node:	numa node

+ *

+ * Allocate enough pages to cover @size from the page level

+ * allocator and map them into contiguous kernel virtual space.

+ *

+ * For tight control over page level allocator and protection flags

+ * use __vmalloc() instead.

+ */

 void *vmalloc_node(unsigned long size, int node)

 {

 	return vmalloc(size);

 }

 EXPORT_SYMBOL(vmalloc_node);

+/**

+ * vzalloc_node - allocate memory on a specific node with zero fill

+ * @size:	allocation size

+ * @node:	numa node

+ *

+ * Allocate enough pages to cover @size from the page level

+ * allocator and map them into contiguous kernel virtual space.

+ * The memory allocated is set to zero.

+ *

+ * For tight control over page level allocator and protection flags

+ * use __vmalloc() instead.

+ */

+void *vzalloc_node(unsigned long size, int node)

+{

+	return vzalloc(size);

+}

+EXPORT_SYMBOL(vzalloc_node);

+

 #ifndef PAGE_KERNEL_EXEC

 # define PAGE_KERNEL_EXEC PAGE_KERNEL

 #endif

diff --git a/mm/vmalloc.c b/mm/vmalloc.c

index 12568fa..2e2e7a3 100644

--- a/mm/vmalloc.c

+++ b/mm/vmalloc.c

@@ -1583,6 +1583,13 @@ void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)

 }

 EXPORT_SYMBOL(__vmalloc);

+static inline void *__vmalloc_node_flags(unsigned long size,

+					int node, gfp_t flags)

+{

+	return __vmalloc_node(size, 1, flags, PAGE_KERNEL,

+					node, __builtin_return_address(0));

+}

+

 /**

  *	vmalloc  -  allocate virtually contiguous memory

  *	@size:		allocation size

@@ -1594,12 +1601,28 @@ EXPORT_SYMBOL(__vmalloc);

  */

 void *vmalloc(unsigned long size)

 {

-	return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,

-					-1, __builtin_return_address(0));

+	return __vmalloc_node_flags(size, -1, GFP_KERNEL | __GFP_HIGHMEM);

 }

 EXPORT_SYMBOL(vmalloc);

 /**

+ *	vzalloc - allocate virtually contiguous memory with zero fill

+ *	@size:	allocation size

+ *	Allocate enough pages to cover @size from the page level

+ *	allocator and map them into contiguous kernel virtual space.

+ *	The memory allocated is set to zero.

+ *

+ *	For tight control over page level allocator and protection flags

+ *	use __vmalloc() instead.

+ */

+void *vzalloc(unsigned long size)

+{

+	return __vmalloc_node_flags(size, -1,

+				GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);

+}

+EXPORT_SYMBOL(vzalloc);

+

+/**

  * vmalloc_user - allocate zeroed virtually contiguous memory for userspace

  * @size: allocation size

  *

@@ -1640,6 +1663,25 @@ void *vmalloc_node(unsigned long size, int node)

 }

 EXPORT_SYMBOL(vmalloc_node);

+/**

+ * vzalloc_node - allocate memory on a specific node with zero fill

+ * @size:	allocation size

+ * @node:	numa node

+ *

+ * Allocate enough pages to cover @size from the page level

+ * allocator and map them into contiguous kernel virtual space.

+ * The memory allocated is set to zero.

+ *

+ * For tight control over page level allocator and protection flags

+ * use __vmalloc_node() instead.

+ */

+void *vzalloc_node(unsigned long size, int node)

+{

+	return __vmalloc_node_flags(size, node,

+			 GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO);

+}

+EXPORT_SYMBOL(vzalloc_node);

+

 #ifndef PAGE_KERNEL_EXEC

 # define PAGE_KERNEL_EXEC PAGE_KERNEL

 #endif