[Cluster-devel] [PATCH v6 05/19] mm: Remove 'page_offset' from readahead loop

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <wi...@infradead.org>

Eliminate the page_offset variable which was confusing with the
'offset' parameter and record the start of each consecutive run of
pages in the readahead_control.

Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
---
 mm/readahead.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/mm/readahead.c b/mm/readahead.c
index 3eca59c43a45..74791b96013f 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -162,6 +162,7 @@ void __do_page_cache_readahead(struct address_space 
*mapping,
        struct readahead_control rac = {
                .mapping = mapping,
                .file = filp,
+               ._start = offset,
                ._nr_pages = 0,
        };
 
@@ -175,12 +176,11 @@ void __do_page_cache_readahead(struct address_space 
*mapping,
         */
        for (page_idx = 0; page_idx < nr_to_read; page_idx++) {
                struct page *page;
-               pgoff_t page_offset = offset + page_idx;
 
-               if (page_offset > end_index)
+               if (offset > end_index)
                        break;
 
-               page = xa_load(&mapping->i_pages, page_offset);
+               page = xa_load(&mapping->i_pages, offset);
                if (page && !xa_is_value(page)) {
                        /*
                         * Page already present?  Kick off the current batch
@@ -196,16 +196,18 @@ void __do_page_cache_readahead(struct address_space 
*mapping,
                page = __page_cache_alloc(gfp_mask);
                if (!page)
                        break;
-               page->index = page_offset;
+               page->index = offset;
                list_add(&page->lru, &page_pool);
                if (page_idx == nr_to_read - lookahead_size)
                        SetPageReadahead(page);
                rac._nr_pages++;
+               offset++;
                continue;
 read:
                if (readahead_count(&rac))
                        read_pages(&rac, &page_pool, gfp_mask);
                rac._nr_pages = 0;
+               rac._start = ++offset;
        }
 
        /*
-- 
2.25.0