[PATCH] splice: cleanup __generic_file_splice_read()
The whole shadow/pages logic got overly complex, and this simpler
approach is actually faster in testing.
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/fs/splice.c b/fs/splice.c
index 9f796b1..8b5efcc 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -220,10 +220,10 @@
{
struct address_space *mapping = in->f_mapping;
unsigned int offset, nr_pages;
- struct page *pages[PIPE_BUFFERS], *shadow[PIPE_BUFFERS];
+ struct page *pages[PIPE_BUFFERS];
struct page *page;
- pgoff_t index, pidx;
- int i, j;
+ pgoff_t index;
+ int i;
index = in->f_pos >> PAGE_CACHE_SHIFT;
offset = in->f_pos & ~PAGE_CACHE_MASK;
@@ -238,41 +238,13 @@
do_page_cache_readahead(mapping, in, index, nr_pages);
/*
- * Get as many pages from the page cache as possible..
- * Start IO on the page cache entries we create (we
- * can assume that any pre-existing ones we find have
- * already had IO started on them).
- */
- i = find_get_pages(mapping, index, nr_pages, pages);
-
- /*
- * common case - we found all pages and they are contiguous,
- * kick them off
- */
- if (i && (pages[i - 1]->index == index + i - 1))
- goto splice_them;
-
- /*
- * fill shadow[] with pages at the right locations, so we only
- * have to fill holes
- */
- memset(shadow, 0, nr_pages * sizeof(struct page *));
- for (j = 0; j < i; j++)
- shadow[pages[j]->index - index] = pages[j];
-
- /*
* now fill in the holes
*/
- for (i = 0, pidx = index; i < nr_pages; pidx++, i++) {
- int error;
-
- if (shadow[i])
- continue;
-
+ for (i = 0; i < nr_pages; i++, index++) {
/*
* no page there, look one up / create it
*/
- page = find_or_create_page(mapping, pidx,
+ page = find_or_create_page(mapping, index,
mapping_gfp_mask(mapping));
if (!page)
break;
@@ -280,31 +252,20 @@
if (PageUptodate(page))
unlock_page(page);
else {
- error = mapping->a_ops->readpage(in, page);
+ int error = mapping->a_ops->readpage(in, page);
if (unlikely(error)) {
page_cache_release(page);
break;
}
}
- shadow[i] = page;
+ pages[i] = page;
}
- if (!i) {
- for (i = 0; i < nr_pages; i++) {
- if (shadow[i])
- page_cache_release(shadow[i]);
- }
- return 0;
- }
+ if (i)
+ return move_to_pipe(pipe, pages, i, offset, len, flags);
- memcpy(pages, shadow, i * sizeof(struct page *));
-
- /*
- * Now we splice them into the pipe..
- */
-splice_them:
- return move_to_pipe(pipe, pages, i, offset, len, flags);
+ return 0;
}
/**