readahead: convert splice invocations

Convert splice reads to use on-demand readahead.

Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
Cc: Steven Pratt <slpratt@austin.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Jens Axboe <axboe@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 11 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 53fc2082a468..722449f7d5d6 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -287,12 +287,6 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                 nr_pages = PIPE_BUFFERS;
 
         /*
-         * Don't try to 2nd guess the read-ahead logic, call into
-         * page_cache_readahead() like the page cache reads would do.
-         */
-        page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);
-
-        /*
          * Lookup the (hopefully) full range of pages we need.
          */
         spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, pages);
@@ -310,11 +304,8 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                  */
                 page = find_get_page(mapping, index);
                 if (!page) {
-                        /*
-                         * Make sure the read-ahead engine is notified
-                         * about this failure.
-                         */
-                        handle_ra_miss(mapping, &in->f_ra, index);
+                        page_cache_readahead_ondemand(mapping, &in->f_ra, in,
+                                        NULL, index, nr_pages - spd.nr_pages);
 
                         /*
                          * page didn't exist, allocate one.
@@ -361,6 +352,10 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
                 this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff);
                 page = pages[page_nr];
 
+                if (PageReadahead(page))
+                        page_cache_readahead_ondemand(mapping, &in->f_ra, in,
+                                        page, index, nr_pages - page_nr);
+
                 /*
                  * If the page isn't uptodate, we may need to start io on it
                  */
@@ -453,6 +448,7 @@ fill_it:
          */
         while (page_nr < nr_pages)
                 page_cache_release(pages[page_nr++]);
+        in->f_ra.prev_index = index;
 
         if (spd.nr_pages)
                 return splice_to_pipe(pipe, &spd);