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-rw-r--r--fs/fuse/dev.c28
1 files changed, 20 insertions, 8 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 11246e7965e8..74171d568621 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -431,10 +431,16 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
if (test_and_set_bit(FR_FINISHED, &req->flags))
goto put_request;
-
- spin_lock(&fiq->waitq.lock);
- list_del_init(&req->intr_entry);
- spin_unlock(&fiq->waitq.lock);
+ /*
+ * test_and_set_bit() implies smp_mb() between bit
+ * changing and below intr_entry check. Pairs with
+ * smp_mb() from queue_interrupt().
+ */
+ if (!list_empty(&req->intr_entry)) {
+ 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));
if (test_bit(FR_BACKGROUND, &req->flags)) {
@@ -473,12 +479,18 @@ put_request:
static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req)
{
spin_lock(&fiq->waitq.lock);
- if (test_bit(FR_FINISHED, &req->flags)) {
- spin_unlock(&fiq->waitq.lock);
- return;
- }
if (list_empty(&req->intr_entry)) {
list_add_tail(&req->intr_entry, &fiq->interrupts);
+ /*
+ * Pairs with smp_mb() implied by test_and_set_bit()
+ * from request_end().
+ */
+ smp_mb();
+ if (test_bit(FR_FINISHED, &req->flags)) {
+ list_del_init(&req->intr_entry);
+ spin_unlock(&fiq->waitq.lock);
+ return;
+ }
wake_up_locked(&fiq->waitq);
kill_fasync(&fiq->fasync, SIGIO, POLL_IN);
}