2/2 splice: dont readpage

Splice does not need to readpage to bring the page uptodate before writing
to it, because prepare_write will take care of that for us.

Splice is also wrong to SetPageUptodate before the page is actually uptodate.
This results in the old uninitialised memory leak. This gets fixed as a
matter of course when removing the readpage logic.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/fs/splice.c b/fs/splice.c
index badc78ff12466c6bed3eb36030d9d4ddf49ed034..ae50208e3e6c174e178b35d444de197a85341656 100644 (file)
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -593,36 +593,6 @@ find_page:
                        goto out;
        }
 
-       /*
-        * We get here with the page locked. If the page is also
-        * uptodate, we don't need to do more. If it isn't, we
-        * may need to bring it in if we are not going to overwrite
-        * the full page.
-        */
-       if (!PageUptodate(page)) {
-               if (this_len < PAGE_CACHE_SIZE) {
-                       ret = mapping->a_ops->readpage(file, page);
-                       if (unlikely(ret))
-                               goto out;
-
-                       lock_page(page);
-
-                       if (!PageUptodate(page)) {
-                               /*
-                                * Page got invalidated, repeat.
-                                */
-                               if (!page->mapping) {
-                                       unlock_page(page);
-                                       page_cache_release(page);
-                                       goto find_page;
-                               }
-                               ret = -EIO;
-                               goto out;
-                       }
-               } else
-                       SetPageUptodate(page);
-       }
-
        ret = mapping->a_ops->prepare_write(file, page, offset, offset+this_len);
        if (unlikely(ret)) {
                loff_t isize = i_size_read(mapping->host);