memblock: split memblock_find_base() out of __memblock_alloc_base()

This will be used by the array resize code and might prove useful
to some arch code as well at which point it can be made non-static.

Also add comment as to why aligning size is important

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

v2. Fix loss of size alignment
v3. Fix result code

mm/memblock.c

@@ -345,12 +345,15 @@ phys_addr_t __init memblock_alloc_nid(phys_addr_t size, phys_addr_t align, int n
 
 	BUG_ON(0 == size);
 
+	/* We align the size to limit fragmentation. Without this, a lot of
+	 * small allocs quickly eat up the whole reserve array on sparc
+	 */
+	size = memblock_align_up(size, align);
+
 	/* We do a bottom-up search for a region with the right
 	 * nid since that's easier considering how memblock_nid_range()
 	 * works
 	 */
-	size = memblock_align_up(size, align);
-
 	for (i = 0; i < mem->cnt; i++) {
 		phys_addr_t ret = memblock_alloc_nid_region(&mem->regions[i],
 					       size, align, nid);
@@ -366,29 +369,14 @@ phys_addr_t __init memblock_alloc(phys_addr_t size, phys_addr_t align)
 	return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
 }
 
-phys_addr_t __init memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
-{
-	phys_addr_t alloc;
-
-	alloc = __memblock_alloc_base(size, align, max_addr);
-
-	if (alloc == 0)
-		panic("ERROR: Failed to allocate 0x%llx bytes below 0x%llx.\n",
-		      (unsigned long long) size, (unsigned long long) max_addr);
-
-	return alloc;
-}
-
-phys_addr_t __init __memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
+static phys_addr_t __init memblock_find_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
 {
 	long i;
 	phys_addr_t base = 0;
 	phys_addr_t res_base;
 
 	BUG_ON(0 == size);
 
-	size = memblock_align_up(size, align);
-
 	/* Pump up max_addr */
 	if (max_addr == MEMBLOCK_ALLOC_ACCESSIBLE)
 		max_addr = memblock.current_limit;
@@ -405,13 +393,43 @@ phys_addr_t __init __memblock_alloc_base(phys_addr_t size, phys_addr_t align, ph
 			continue;
 		base = min(memblockbase + memblocksize, max_addr);
 		res_base = memblock_find_region(memblockbase, base, size, align);
-		if (res_base != MEMBLOCK_ERROR &&
-		    memblock_add_region(&memblock.reserved, res_base, size) >= 0)
+		if (res_base != MEMBLOCK_ERROR)
 			return res_base;
 	}
+	return MEMBLOCK_ERROR;
+}
+
+phys_addr_t __init __memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
+{	
+	phys_addr_t found;
+
+	/* We align the size to limit fragmentation. Without this, a lot of
+	 * small allocs quickly eat up the whole reserve array on sparc
+	 */
+	size = memblock_align_up(size, align);
+
+	found = memblock_find_base(size, align, max_addr);
+	if (found != MEMBLOCK_ERROR &&
+	    memblock_add_region(&memblock.reserved, found, size) >= 0)
+		return found;
+
 	return 0;
 }
 
+phys_addr_t __init memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
+{
+	phys_addr_t alloc;
+
+	alloc = __memblock_alloc_base(size, align, max_addr);
+
+	if (alloc == 0)
+		panic("ERROR: Failed to allocate 0x%llx bytes below 0x%llx.\n",
+		      (unsigned long long) size, (unsigned long long) max_addr);
+
+	return alloc;
+}
+
+
 /* You must call memblock_analyze() before this. */
 phys_addr_t __init memblock_phys_mem_size(void)
 {