bootmem: clean up free_all_bootmem_core

Rewrite the code in a more concise way using less variables.

[akpm@linux-foundation.org: fix printk warnings]
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 38 insertions, 45 deletions

diff --git a/mm/bootmem.c b/mm/bootmem.c
index 9da7d4097810..300d126ec533 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -144,66 +144,59 @@ unsigned long __init init_bootmem(unsigned long start, unsigned long pages)
 
 static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata)
 {
+        int aligned;
         struct page *page;
-        unsigned long pfn;
-        unsigned long i, count;
-        unsigned long idx, pages;
-        unsigned long *map;
-        int gofast = 0;
-
-        BUG_ON(!bdata->node_bootmem_map);
-
-        count = 0;
-        /* first extant page of the node */
-        pfn = PFN_DOWN(bdata->node_boot_start);
-        idx = bdata->node_low_pfn - pfn;
-        map = bdata->node_bootmem_map;
+        unsigned long start, end, pages, count = 0;
+
+        if (!bdata->node_bootmem_map)
+                return 0;
+
+        start = PFN_DOWN(bdata->node_boot_start);
+        end = bdata->node_low_pfn;
+
         /*
-         * Check if we are aligned to BITS_PER_LONG pages.  If so, we might
-         * be able to free page orders of that size at once.
+         * If the start is aligned to the machines wordsize, we might
+         * be able to free pages in bulks of that order.
          */
-        if (!(pfn & (BITS_PER_LONG-1)))
-                gofast = 1;
+        aligned = !(start & (BITS_PER_LONG - 1));
+
+        bdebug("nid=%td start=%lx end=%lx aligned=%d\n",
+                bdata - bootmem_node_data, start, end, aligned);
+
+        while (start < end) {
+                unsigned long *map, idx, vec;
 
-        for (i = 0; i < idx; ) {
-                unsigned long v = ~map[i / BITS_PER_LONG];
+                map = bdata->node_bootmem_map;
+                idx = start - PFN_DOWN(bdata->node_boot_start);
+                vec = ~map[idx / BITS_PER_LONG];
 
-                if (gofast && v == ~0UL) {
-                        int order;
+                if (aligned && vec == ~0UL && start + BITS_PER_LONG < end) {
+                        int order = ilog2(BITS_PER_LONG);
 
-                        page = pfn_to_page(pfn);
+                        __free_pages_bootmem(pfn_to_page(start), order);
                         count += BITS_PER_LONG;
-                        order = ffs(BITS_PER_LONG) - 1;
-                        __free_pages_bootmem(page, order);
-                        i += BITS_PER_LONG;
-                        page += BITS_PER_LONG;
-                } else if (v) {
-                        unsigned long m;
-
-                        page = pfn_to_page(pfn);
-                        for (m = 1; m && i < idx; m<<=1, page++, i++) {
-                                if (v & m) {
-                                        count++;
+                } else {
+                        unsigned long off = 0;
+
+                        while (vec && off < BITS_PER_LONG) {
+                                if (vec & 1) {
+                                        page = pfn_to_page(start + off);
                                         __free_pages_bootmem(page, 0);
+                                        count++;
                                 }
+                                vec >>= 1;
+                                off++;
                         }
-                } else {
-                        i += BITS_PER_LONG;
                 }
-                pfn += BITS_PER_LONG;
+                start += BITS_PER_LONG;
         }
 
-        /*
-         * Now free the allocator bitmap itself, it's not
-         * needed anymore:
-         */
         page = virt_to_page(bdata->node_bootmem_map);
         pages = bdata->node_low_pfn - PFN_DOWN(bdata->node_boot_start);
-        idx = bootmem_bootmap_pages(pages);
-        for (i = 0; i < idx; i++, page++)
-                __free_pages_bootmem(page, 0);
-        count += i;
-        bdata->node_bootmem_map = NULL;
+        pages = bootmem_bootmap_pages(pages);
+        count += pages;
+        while (pages--)
+                __free_pages_bootmem(page++, 0);
 
         bdebug("nid=%td released=%lx\n", bdata - bootmem_node_data, count);