[PATCH] splice: cleanup the SPLICE_F_NONBLOCK handling
- generic_file_splice_read() more readable and correct
- Don't bail on page allocation with NONBLOCK set, just don't allow
direct blocking on IO (eg lock_page).
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/fs/splice.c b/fs/splice.c
index 7e85855..78cd264 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -279,14 +279,6 @@
page = find_get_page(mapping, index);
if (!page) {
/*
- * If in nonblock mode then dont block on
- * readpage (we've kicked readahead so there
- * will be asynchronous progress):
- */
- if (flags & SPLICE_F_NONBLOCK)
- break;
-
- /*
* page didn't exist, allocate one
*/
page = page_cache_alloc_cold(mapping);
@@ -307,6 +299,13 @@
* If the page isn't uptodate, we may need to start io on it
*/
if (!PageUptodate(page)) {
+ /*
+ * If in nonblock mode then dont block on waiting
+ * for an in-flight io page
+ */
+ if (flags & SPLICE_F_NONBLOCK)
+ break;
+
lock_page(page);
/*
@@ -400,17 +399,20 @@
while (len) {
ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
- if (ret <= 0)
+ if (ret < 0)
break;
+ else if (!ret) {
+ if (spliced)
+ break;
+ if (flags & SPLICE_F_NONBLOCK) {
+ ret = -EAGAIN;
+ break;
+ }
+ }
*ppos += ret;
len -= ret;
spliced += ret;
-
- if (!(flags & SPLICE_F_NONBLOCK))
- continue;
- ret = -EAGAIN;
- break;
}
if (spliced)