Backport from ml:
commit 365ae710df91edc97d24817e3271e01bffaaee32
Author: Miklos Szeredi <[email protected]>
Date: Wed Jul 1 16:26:06 2015 +0200
fuse: request_end(): do once
When the connection is aborted it is possible that request_end() will be
called twice. Use atomic test and set to do the actual ending only once.
test_and_set_bit() also provides the necessary barrier semantics so no
explicit smp_wmb() is necessary.
Signed-off-by: Miklos Szeredi <[email protected]>
Reviewed-by: Ashish Samant <[email protected]>
Signed-off-by: Maxim Patlasov <[email protected]>
---
fs/fuse/dev.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 50812a0..4d16a1c 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -367,14 +367,18 @@ __releases(fc->lock)
{
struct fuse_iqueue *fiq = &fc->iq;
void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
+
+ if (test_and_set_bit(FR_FINISHED, &req->flags)) {
+ spin_unlock(&fc->lock);
+ return;
+ }
+
req->end = NULL;
spin_lock(&fiq->waitq.lock);
list_del_init(&req->intr_entry);
spin_unlock(&fiq->waitq.lock);
WARN_ON(test_bit(FR_PENDING, &req->flags));
WARN_ON(test_bit(FR_SENT, &req->flags));
- smp_wmb();
- set_bit(FR_FINISHED, &req->flags);
if (test_bit(FR_BACKGROUND, &req->flags)) {
clear_bit(FR_BACKGROUND, &req->flags);
if (fc->num_background == fc->max_background)
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