From: Hao Xu <howeyxu@xxxxxxxxxxx>
When SPLICE_F_NONBLOCK is set, splice() still may be blocked by pipe
lock in pipe to pipe scenario. Add trylock logic to make it more
nonblock
Signed-off-by: Hao Xu <howeyxu@xxxxxxxxxxx>
---
fs/splice.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/fs/splice.c b/fs/splice.c
index 047b79db8eb5..b087e00ed079 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1372,7 +1372,12 @@ static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
return 0;
ret = 0;
- pipe_lock(pipe);
+ if (flags & SPLICE_F_NONBLOCK) {
+ if (!pipe_trylock(pipe))
+ return -EAGAIN;
+ } else {
+ pipe_lock(pipe);
+ }
while (pipe_empty(pipe->head, pipe->tail)) {
if (signal_pending(current)) {
@@ -1408,7 +1413,12 @@ static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
return 0;
ret = 0;
- pipe_lock(pipe);
+ if (flags & SPLICE_F_NONBLOCK) {
+ if (!pipe_trylock(pipe))
+ return -EAGAIN;
+ } else {
+ pipe_lock(pipe);
+ }
while (pipe_full(pipe->head, pipe->tail, pipe->max_usage)) {
if (!pipe->readers) {
@@ -1460,7 +1470,12 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
* grabbing by pipe info address. Otherwise two different processes
* could deadlock (one doing tee from A -> B, the other from B -> A).
*/
- pipe_double_lock(ipipe, opipe);
+ if (flags & SPLICE_F_NONBLOCK) {
+ if (!pipe_double_trylock(ipipe, opipe))
+ return -EAGAIN;
+ } else {
+ pipe_double_lock(ipipe, opipe);
+ }
i_tail = ipipe->tail;
i_mask = ipipe->ring_size - 1;
--
2.25.1
