From: "Matthew Wilcox (Oracle)" <[email protected]> Move the declaration of 'page' to inside the loop and move the 'kick off a fresh batch' code to the end of the function for easier use in subsequent patches.
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> --- mm/readahead.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/mm/readahead.c b/mm/readahead.c index 15329309231f..3eca59c43a45 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -154,7 +154,6 @@ void __do_page_cache_readahead(struct address_space *mapping, unsigned long lookahead_size) { struct inode *inode = mapping->host; - struct page *page; unsigned long end_index; /* The last page we want to read */ LIST_HEAD(page_pool); int page_idx; @@ -175,6 +174,7 @@ void __do_page_cache_readahead(struct address_space *mapping, * Preallocate as many pages as we will need. */ 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) @@ -183,14 +183,14 @@ void __do_page_cache_readahead(struct address_space *mapping, page = xa_load(&mapping->i_pages, page_offset); if (page && !xa_is_value(page)) { /* - * Page already present? Kick off the current batch of - * contiguous pages before continuing with the next - * batch. + * Page already present? Kick off the current batch + * of contiguous pages before continuing with the + * next batch. This page may be the one we would + * have intended to mark as Readahead, but we don't + * have a stable reference to this page, and it's + * not worth getting one just for that. */ - if (readahead_count(&rac)) - read_pages(&rac, &page_pool, gfp_mask); - rac._nr_pages = 0; - continue; + goto read; } page = __page_cache_alloc(gfp_mask); @@ -201,6 +201,11 @@ void __do_page_cache_readahead(struct address_space *mapping, if (page_idx == nr_to_read - lookahead_size) SetPageReadahead(page); rac._nr_pages++; + continue; +read: + if (readahead_count(&rac)) + read_pages(&rac, &page_pool, gfp_mask); + rac._nr_pages = 0; } /* -- 2.25.0
