shmem: fix faulting into a hole, not taking i_mutex

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / compaction.c

diff --git a/mm/compaction.c b/mm/compaction.c
index b48c525..5f702ef 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -251,7 +251,6 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 {
        int nr_scanned = 0, total_isolated = 0;
        struct page *cursor, *valid_page = NULL;
-       unsigned long nr_strict_required = end_pfn - blockpfn;
        unsigned long flags;
        bool locked = false;
 
@@ -264,11 +263,12 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 
                nr_scanned++;
                if (!pfn_valid_within(blockpfn))
-                       continue;
+                       goto isolate_fail;
+
                if (!valid_page)
                        valid_page = page;
                if (!PageBuddy(page))
-                       continue;
+                       goto isolate_fail;
 
                /*
                 * The zone lock must be held to isolate freepages.
@@ -289,12 +289,10 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
 
                /* Recheck this is a buddy page under lock */
                if (!PageBuddy(page))
-                       continue;
+                       goto isolate_fail;
 
                /* Found a free page, break it into order-0 pages */
                isolated = split_free_page(page);
-               if (!isolated && strict)
-                       break;
                total_isolated += isolated;
                for (i = 0; i < isolated; i++) {
                        list_add(&page->lru, freelist);
@@ -305,7 +303,15 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
                if (isolated) {
                        blockpfn += isolated - 1;
                        cursor += isolated - 1;
+                       continue;
                }
+
+isolate_fail:
+               if (strict)
+                       break;
+               else
+                       continue;
+
        }
 
        trace_mm_compaction_isolate_freepages(nr_scanned, total_isolated);
@@ -315,7 +321,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
         * pages requested were isolated. If there were any failures, 0 is
         * returned and CMA will fail.
         */
-       if (strict && nr_strict_required > total_isolated)
+       if (strict && blockpfn < end_pfn)
                total_isolated = 0;
 
        if (locked)
@@ -660,16 +666,20 @@ static void isolate_freepages(struct zone *zone,
                                struct compact_control *cc)
 {
        struct page *page;
-       unsigned long high_pfn, low_pfn, pfn, z_end_pfn, end_pfn;
+       unsigned long high_pfn, low_pfn, pfn, z_end_pfn;
        int nr_freepages = cc->nr_freepages;
        struct list_head *freelist = &cc->freepages;
 
        /*
         * Initialise the free scanner. The starting point is where we last
-        * scanned from (or the end of the zone if starting). The low point
-        * is the end of the pageblock the migration scanner is using.
+        * successfully isolated from, zone-cached value, or the end of the
+        * zone when isolating for the first time. We need this aligned to
+        * the pageblock boundary, because we do pfn -= pageblock_nr_pages
+        * in the for loop.
+        * The low boundary is the end of the pageblock the migration scanner
+        * is using.
         */
-       pfn = cc->free_pfn;
+       pfn = cc->free_pfn & ~(pageblock_nr_pages-1);
        low_pfn = ALIGN(cc->migrate_pfn + 1, pageblock_nr_pages);
 
        /*
@@ -689,6 +699,7 @@ static void isolate_freepages(struct zone *zone,
        for (; pfn >= low_pfn && cc->nr_migratepages > nr_freepages;
                                        pfn -= pageblock_nr_pages) {
                unsigned long isolated;
+               unsigned long end_pfn;
 
                /*
                 * This can iterate a massively long zone without finding any
@@ -723,13 +734,10 @@ static void isolate_freepages(struct zone *zone,
                isolated = 0;
 
                /*
-                * As pfn may not start aligned, pfn+pageblock_nr_page
-                * may cross a MAX_ORDER_NR_PAGES boundary and miss
-                * a pfn_valid check. Ensure isolate_freepages_block()
-                * only scans within a pageblock
+                * Take care when isolating in last pageblock of a zone which
+                * ends in the middle of a pageblock.
                 */
-               end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
-               end_pfn = min(end_pfn, z_end_pfn);
+               end_pfn = min(pfn + pageblock_nr_pages, z_end_pfn);
                isolated = isolate_freepages_block(cc, pfn, end_pfn,
                                                   freelist, false);
                nr_freepages += isolated;