diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 34106f6e66a0..3f498630f421 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -213,10 +213,13 @@ EXPORT_SYMBOL_GPL(fuse_req_hash); /* * A new request is available, wake fiq->waitq */ -static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq) +static void fuse_dev_wake_and_unlock(struct fuse_iqueue *fiq, bool sync) __releases(fiq->lock) { - wake_up(&fiq->waitq); + if (sync) + wake_up_sync(&fiq->waitq); + else + wake_up(&fiq->waitq); kill_fasync(&fiq->fasync, SIGIO, POLL_IN); spin_unlock(&fiq->lock); } @@ -233,7 +236,7 @@ void fuse_dev_queue_forget(struct fuse_iqueue *fiq, if (fiq->connected) { fiq->forget_list_tail->next = forget; fiq->forget_list_tail = forget; - fuse_dev_wake_and_unlock(fiq); + fuse_dev_wake_and_unlock(fiq, false); } else { kfree(forget); spin_unlock(&fiq->lock); @@ -255,7 +258,7 @@ void fuse_dev_queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req) list_del_init(&req->intr_entry); spin_unlock(&fiq->lock); } else { - fuse_dev_wake_and_unlock(fiq); + fuse_dev_wake_and_unlock(fiq, false); } } else { spin_unlock(&fiq->lock); @@ -285,11 +288,13 @@ EXPORT_SYMBOL_GPL(fuse_request_assign_unique); static void fuse_dev_queue_req(struct fuse_iqueue *fiq, struct fuse_req *req) { + bool sync = test_and_clear_bit(FR_SYNC_WAKEUP, &req->flags); + spin_lock(&fiq->lock); if (fiq->connected) { fuse_request_assign_unique_locked(fiq, req); list_add_tail(&req->list, &fiq->pending); - fuse_dev_wake_and_unlock(fiq); + fuse_dev_wake_and_unlock(fiq, sync); } else { spin_unlock(&fiq->lock); req->out.h.error = -ENOTCONN; @@ -752,6 +757,11 @@ static void __fuse_request_send(struct fuse_req *req) /* acquire extra reference, since request is still needed after fuse_request_end() */ __fuse_get_request(req); + /* + * This is a synchronous request: the caller will block waiting for + * the answer. Hint the scheduler via wake_up_sync(). + */ + set_bit(FR_SYNC_WAKEUP, &req->flags); fuse_send_one(fiq, req); request_wait_answer(req); @@ -1824,7 +1834,7 @@ void fuse_chan_resend(struct fuse_chan *fch) } /* iq and pq requests are both oldest to newest */ list_splice(&to_queue, &fiq->pending); - fuse_dev_wake_and_unlock(fiq); + fuse_dev_wake_and_unlock(fiq, false); } /* Look up request on processing list by unique ID */ diff --git a/fs/fuse/fuse_dev_i.h b/fs/fuse/fuse_dev_i.h index f41749f484df..4b412a76225f 100644 --- a/fs/fuse/fuse_dev_i.h +++ b/fs/fuse/fuse_dev_i.h @@ -38,6 +38,8 @@ struct fuse_iqueue; * @FR_PRIVATE: request is on private list * @FR_ASYNC: request is asynchronous * @FR_URING: request is handled through fuse-io-uring + * @FR_SYNC_WAKEUP: use synchronous wakeup when queueing this request to + * give the scheduler a hint about the waker task */ enum fuse_req_flag { FR_ISREPLY, @@ -53,6 +55,7 @@ enum fuse_req_flag { FR_PRIVATE, FR_ASYNC, FR_URING, + FR_SYNC_WAKEUP, }; /**