[PATCH v2 1/2] vmalloc: Factor vmap_alloc() out of vm_map_ram()

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

Introduce vmap_alloc() to simply get the address space.  This allows
for code sharing in the next patch.

Suggested-by: Uladzislau Rezki <urezki@gmail.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/vmalloc.c | 41 +++++++++++++++++++++++------------------
 1 file changed, 23 insertions(+), 18 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ccaa461998f3..dcab1d3cf185 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2230,6 +2230,27 @@ void vm_unmap_ram(const void *mem, unsigned int count)
 }
 EXPORT_SYMBOL(vm_unmap_ram);
 
+static void *vmap_alloc(size_t size, int node)
+{
+	void *mem;
+
+	if (likely(size <= (VMAP_MAX_ALLOC * PAGE_SIZE))) {
+		mem = vb_alloc(size, GFP_KERNEL);
+		if (IS_ERR(mem))
+			mem = NULL;
+	} else {
+		struct vmap_area *va;
+		va = alloc_vmap_area(size, PAGE_SIZE,
+				VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
+		if (IS_ERR(va))
+			mem = NULL;
+		else
+			mem = (void *)va->va_start;
+	}
+
+	return mem;
+}
+
 /**
  * vm_map_ram - map pages linearly into kernel virtual address (vmalloc space)
  * @pages: an array of pointers to the pages to be mapped
@@ -2247,24 +2268,8 @@ EXPORT_SYMBOL(vm_unmap_ram);
 void *vm_map_ram(struct page **pages, unsigned int count, int node)
 {
 	unsigned long size = (unsigned long)count << PAGE_SHIFT;
-	unsigned long addr;
-	void *mem;
-
-	if (likely(count <= VMAP_MAX_ALLOC)) {
-		mem = vb_alloc(size, GFP_KERNEL);
-		if (IS_ERR(mem))
-			return NULL;
-		addr = (unsigned long)mem;
-	} else {
-		struct vmap_area *va;
-		va = alloc_vmap_area(size, PAGE_SIZE,
-				VMALLOC_START, VMALLOC_END, node, GFP_KERNEL);
-		if (IS_ERR(va))
-			return NULL;
-
-		addr = va->va_start;
-		mem = (void *)addr;
-	}
+	void *mem = vmap_alloc(size, node);
+	unsigned long addr = (unsigned long)mem;
 
 	if (vmap_pages_range(addr, addr + size, PAGE_KERNEL,
 				pages, PAGE_SHIFT) < 0) {
-- 
2.35.1