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authorMiklos Szeredi <miklos@szeredi.hu>2010-08-03 12:48:50 +0200
committerJens Axboe <jaxboe@fusionio.com>2010-08-07 18:52:56 +0200
commit6965031d331a642e31278fa1b5bd47f372ffdd5d (patch)
tree403363107b75f4efedd877c75ed8099377d41ec7
parent7901d14144311c930918b1222aae7611284c63eb (diff)
downloadop-kernel-dev-6965031d331a642e31278fa1b5bd47f372ffdd5d.zip
op-kernel-dev-6965031d331a642e31278fa1b5bd47f372ffdd5d.tar.gz
splice: fix misuse of SPLICE_F_NONBLOCK
SPLICE_F_NONBLOCK is clearly documented to only affect blocking on the pipe. In __generic_file_splice_read(), however, it causes an EAGAIN if the page is currently being read. This makes it impossible to write an application that only wants failure if the pipe is full. For example if the same process is handling both ends of a pipe and isn't otherwise able to determine whether a splice to the pipe will fill it or not. We could make the read non-blocking on O_NONBLOCK or some other splice flag, but for now this is the simplest fix. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
-rw-r--r--fs/splice.c12
1 files changed, 1 insertions, 11 deletions
diff --git a/fs/splice.c b/fs/splice.c
index ec11c52..8f1dfae 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -399,17 +399,7 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
* 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) {
- if (!trylock_page(page)) {
- error = -EAGAIN;
- break;
- }
- } else
- lock_page(page);
+ lock_page(page);
/*
* Page was truncated, or invalidated by the
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