1 files changed, 11 insertions, 13 deletions

diff --git a/mm/swap_state.c b/mm/swap_state.c
index ea6b32d61873..9d3dd3763cf7 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -372,25 +372,23 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
 struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
                         struct vm_area_struct *vma, unsigned long addr)
 {
-        int nr_pages;
         struct page *page;
-        unsigned long offset;
-        unsigned long end_offset;
+        unsigned long offset = swp_offset(entry);
+        unsigned long start_offset, end_offset;
+        unsigned long mask = (1UL << page_cluster) - 1;
 
-        /*
-         * Get starting offset for readaround, and number of pages to read.
-         * Adjust starting address by readbehind (for NUMA interleave case)?
-         * No, it's very unlikely that swap layout would follow vma layout,
-         * more likely that neighbouring swap pages came from the same node:
-         * so use the same "addr" to choose the same node for each swap read.
-         */
-        nr_pages = valid_swaphandles(entry, &offset);
-        for (end_offset = offset + nr_pages; offset < end_offset; offset++) {
+        /* Read a page_cluster sized and aligned cluster around offset. */
+        start_offset = offset & ~mask;
+        end_offset = offset | mask;
+        if (!start_offset)      /* First page is swap header. */
+                start_offset++;
+
+        for (offset = start_offset; offset <= end_offset ; offset++) {
                 /* Ok, do the async read-ahead now */
                 page = read_swap_cache_async(swp_entry(swp_type(entry), offset),
                                                 gfp_mask, vma, addr);
                 if (!page)
-                        break;
+                        continue;
                 page_cache_release(page);
         }
         lru_add_drain();        /* Push any new pages onto the LRU now */