[PATCH v3 01/11] mm: vmalloc: Add va_alloc() helper

["Uladzislau Rezki (Sony)" <urezki@gmail.com>]

Currently __alloc_vmap_area() function contains an open codded
logic that finds and adjusts a VA based on allocation request.

Introduce a va_alloc() helper that adjusts found VA only. There
is no a functional change as a result of this patch.

Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
---
 mm/vmalloc.c | 41 ++++++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index d12a17fc0c17..739401a9eafc 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1481,6 +1481,32 @@ adjust_va_to_fit_type(struct rb_root *root, struct list_head *head,
 	return 0;
 }
 
+static unsigned long
+va_alloc(struct vmap_area *va,
+		struct rb_root *root, struct list_head *head,
+		unsigned long size, unsigned long align,
+		unsigned long vstart, unsigned long vend)
+{
+	unsigned long nva_start_addr;
+	int ret;
+
+	if (va->va_start > vstart)
+		nva_start_addr = ALIGN(va->va_start, align);
+	else
+		nva_start_addr = ALIGN(vstart, align);
+
+	/* Check the "vend" restriction. */
+	if (nva_start_addr + size > vend)
+		return vend;
+
+	/* Update the free vmap_area. */
+	ret = adjust_va_to_fit_type(root, head, va, nva_start_addr, size);
+	if (WARN_ON_ONCE(ret))
+		return vend;
+
+	return nva_start_addr;
+}
+
 /*
  * Returns a start address of the newly allocated area, if success.
  * Otherwise a vend is returned that indicates failure.
@@ -1493,7 +1519,6 @@ __alloc_vmap_area(struct rb_root *root, struct list_head *head,
 	bool adjust_search_size = true;
 	unsigned long nva_start_addr;
 	struct vmap_area *va;
-	int ret;
 
 	/*
 	 * Do not adjust when:
@@ -1511,18 +1536,8 @@ __alloc_vmap_area(struct rb_root *root, struct list_head *head,
 	if (unlikely(!va))
 		return vend;
 
-	if (va->va_start > vstart)
-		nva_start_addr = ALIGN(va->va_start, align);
-	else
-		nva_start_addr = ALIGN(vstart, align);
-
-	/* Check the "vend" restriction. */
-	if (nva_start_addr + size > vend)
-		return vend;
-
-	/* Update the free vmap_area. */
-	ret = adjust_va_to_fit_type(root, head, va, nva_start_addr, size);
-	if (WARN_ON_ONCE(ret))
+	nva_start_addr = va_alloc(va, root, head, size, align, vstart, vend);
+	if (nva_start_addr == vend)
 		return vend;
 
 #if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
-- 
2.39.2