readahead: code cleanup

[deliverable/linux.git] / mm / filemap.c

diff --git a/mm/filemap.c b/mm/filemap.c
index cbea95a25283d5735f90f3729721240c75e4df54..5631d6b2a62d8c18c43472dd5bf4eae3f5e88d10 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -868,6 +868,7 @@ void do_generic_mapping_read(struct address_space *mapping,
        unsigned long last_index;
        unsigned long next_index;
        unsigned long prev_index;
+       unsigned int prev_offset;
        loff_t isize;
        struct page *cached_page;
        int error;
@@ -876,7 +877,8 @@ void do_generic_mapping_read(struct address_space *mapping,
        cached_page = NULL;
        index = *ppos >> PAGE_CACHE_SHIFT;
        next_index = index;
-       prev_index = ra.prev_page;
+       prev_index = ra.prev_index;
+       prev_offset = ra.prev_offset;
        last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
        offset = *ppos & ~PAGE_CACHE_MASK;
 
@@ -924,10 +926,10 @@ page_ok:
                        flush_dcache_page(page);
 
                /*
-                * When (part of) the same page is read multiple times
-                * in succession, only mark it as accessed the first time.
+                * When a sequential read accesses a page several times,
+                * only mark it as accessed the first time.
                 */
-               if (prev_index != index)
+               if (prev_index != index || offset != prev_offset)
                        mark_page_accessed(page);
                prev_index = index;
 
@@ -945,6 +947,8 @@ page_ok:
                offset += ret;
                index += offset >> PAGE_CACHE_SHIFT;
                offset &= ~PAGE_CACHE_MASK;
+               prev_offset = offset;
+               ra.prev_offset = offset;
 
                page_cache_release(page);
                if (ret == nr && desc->count)