+ BUG_ON(!size);
+ BUG_ON(align & (align - 1));
+ BUG_ON(limit && goal + size > limit);
+
+ if (!bdata->node_bootmem_map)
+ return NULL;
+
+ bdebug("nid=%td size=%lx [%lu pages] align=%lx goal=%lx limit=%lx\n",
+ bdata - bootmem_node_data, size, PAGE_ALIGN(size) >> PAGE_SHIFT,
+ align, goal, limit);
+
+ min = bdata->node_min_pfn;
+ max = bdata->node_low_pfn;
+
+ goal >>= PAGE_SHIFT;
+ limit >>= PAGE_SHIFT;
+
+ if (limit && max > limit)
+ max = limit;
+ if (max <= min)
+ return NULL;
+
+ step = max(align >> PAGE_SHIFT, 1UL);
+
+ if (goal && min < goal && goal < max)
+ start = ALIGN(goal, step);
+ else
+ start = ALIGN(min, step);
+
+ sidx = start - bdata->node_min_pfn;;
+ midx = max - bdata->node_min_pfn;
+
+ if (bdata->hint_idx > sidx) {
+ /*
+ * Handle the valid case of sidx being zero and still
+ * catch the fallback below.
+ */
+ fallback = sidx + 1;
+ sidx = ALIGN(bdata->hint_idx, step);
+ }
+
+ while (1) {
+ int merge;
+ void *region;
+ unsigned long eidx, i, start_off, end_off;
+find_block:
+ sidx = find_next_zero_bit(bdata->node_bootmem_map, midx, sidx);
+ sidx = ALIGN(sidx, step);
+ eidx = sidx + PFN_UP(size);
+
+ if (sidx >= midx || eidx > midx)
+ break;
+
+ for (i = sidx; i < eidx; i++)
+ if (test_bit(i, bdata->node_bootmem_map)) {
+ sidx = ALIGN(i, step);
+ if (sidx == i)
+ sidx += step;
+ goto find_block;
+ }
+
+ if (bdata->last_end_off &&
+ PFN_DOWN(bdata->last_end_off) + 1 == sidx)
+ start_off = ALIGN(bdata->last_end_off, align);
+ else
+ start_off = PFN_PHYS(sidx);
+
+ merge = PFN_DOWN(start_off) < sidx;
+ end_off = start_off + size;
+
+ bdata->last_end_off = end_off;
+ bdata->hint_idx = PFN_UP(end_off);
+
+ /*
+ * Reserve the area now:
+ */
+ if (__reserve(bdata, PFN_DOWN(start_off) + merge,
+ PFN_UP(end_off), BOOTMEM_EXCLUSIVE))
+ BUG();
+
+ region = phys_to_virt(PFN_PHYS(bdata->node_min_pfn) +
+ start_off);
+ memset(region, 0, size);
+ return region;
+ }
+
+ if (fallback) {
+ sidx = ALIGN(fallback - 1, step);
+ fallback = 0;
+ goto find_block;
+ }
+
+ return NULL;