[RFC 4/7] mm: factor __alloc_contig_range out

[Minchan Kim <minchan@kernel.org>]

To prepare new API which will reuse most of alloc_contig_range,
this patch factor out the common part as __alloc_contig_range.

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 mm/page_alloc.c | 50 +++++++++++++++++++++++++++----------------------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4caab47377a7..caf393d8b413 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8401,28 +8401,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
 	return 0;
 }
 
-/**
- * alloc_contig_range() -- tries to allocate given range of pages
- * @start:	start PFN to allocate
- * @end:	one-past-the-last PFN to allocate
- * @migratetype:	migratetype of the underlaying pageblocks (either
- *			#MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
- *			in range must have the same migratetype and it must
- *			be either of the two.
- * @gfp_mask:	GFP mask to use during compaction
- *
- * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
- * aligned.  The PFN range must belong to a single zone.
- *
- * The first thing this routine does is attempt to MIGRATE_ISOLATE all
- * pageblocks in the range.  Once isolated, the pageblocks should not
- * be modified by others.
- *
- * Return: zero on success or negative error code.  On success all
- * pages which PFN is in [start, end) are allocated for the caller and
- * need to be freed with free_contig_range().
- */
-int alloc_contig_range(unsigned long start, unsigned long end,
+static int __alloc_contig_range(unsigned long start, unsigned long end,
 		       unsigned migratetype, gfp_t gfp_mask)
 {
 	unsigned long outer_start, outer_end;
@@ -8555,6 +8534,33 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 }
 EXPORT_SYMBOL(alloc_contig_range);
 
+/**
+ * alloc_contig_range() -- tries to allocate given range of pages
+ * @start:	start PFN to allocate
+ * @end:	one-past-the-last PFN to allocate
+ * @migratetype:	migratetype of the underlaying pageblocks (either
+ *			#MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
+ *			in range must have the same migratetype and it must
+ *			be either of the two.
+ * @gfp_mask:	GFP mask to use during compaction
+ *
+ * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
+ * aligned.  The PFN range must belong to a single zone.
+ *
+ * The first thing this routine does is attempt to MIGRATE_ISOLATE all
+ * pageblocks in the range.  Once isolated, the pageblocks should not
+ * be modified by others.
+ *
+ * Return: zero on success or negative error code.  On success all
+ * pages which PFN is in [start, end) are allocated for the caller and
+ * need to be freed with free_contig_range().
+ */
+int alloc_contig_range(unsigned long start, unsigned long end,
+		       unsigned migratetype, gfp_t gfp_mask)
+{
+	return __alloc_contig_range(start, end, migratetype, gfp_mask);
+}
+
 static int __alloc_contig_pages(unsigned long start_pfn,
 				unsigned long nr_pages, gfp_t gfp_mask)
 {
-- 
2.28.0.220.ged08abb693-goog