+static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap)
+{
+ return altmap->base_pfn + altmap->reserve + altmap->alloc
+ + altmap->align;
+}
+
+static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap)
+{
+ unsigned long allocated = altmap->alloc + altmap->align;
+
+ if (altmap->free > allocated)
+ return altmap->free - allocated;
+ return 0;
+}
+
+/**
+ * vmem_altmap_alloc - allocate pages from the vmem_altmap reservation
+ * @altmap - reserved page pool for the allocation
+ * @nr_pfns - size (in pages) of the allocation
+ *
+ * Allocations are aligned to the size of the request
+ */
+static unsigned long __meminit vmem_altmap_alloc(struct vmem_altmap *altmap,
+ unsigned long nr_pfns)
+{
+ unsigned long pfn = vmem_altmap_next_pfn(altmap);
+ unsigned long nr_align;
+
+ nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG);
+ nr_align = ALIGN(pfn, nr_align) - pfn;
+
+ if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap))
+ return ULONG_MAX;
+ altmap->alloc += nr_pfns;
+ altmap->align += nr_align;
+ return pfn + nr_align;
+}
+
+static void * __meminit altmap_alloc_block_buf(unsigned long size,
+ struct vmem_altmap *altmap)
+{
+ unsigned long pfn, nr_pfns;
+ void *ptr;
+
+ if (size & ~PAGE_MASK) {
+ pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",
+ __func__, size);
+ return NULL;
+ }
+
+ nr_pfns = size >> PAGE_SHIFT;
+ pfn = vmem_altmap_alloc(altmap, nr_pfns);
+ if (pfn < ULONG_MAX)
+ ptr = __va(__pfn_to_phys(pfn));
+ else
+ ptr = NULL;
+ pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",
+ __func__, pfn, altmap->alloc, altmap->align, nr_pfns);
+
+ return ptr;
+}
+
+/* need to make sure size is all the same during early stage */
+void * __meminit __vmemmap_alloc_block_buf(unsigned long size, int node,
+ struct vmem_altmap *altmap)
+{
+ if (altmap)
+ return altmap_alloc_block_buf(size, altmap);
+ return alloc_block_buf(size, node);
+}
+