This prepares queueing and sending through io-uring.
Signed-off-by: Bernd Schubert <bschubert@xxxxxxx>
---
fs/fuse/dev_uring.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++
fs/fuse/dev_uring_i.h | 7 ++++
2 files changed, 108 insertions(+)
diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
index 455a42a6b9348dda15dd082d3bfd778279f61e0b..3f1c39bb43e24a7f9c5d4cdd507f56fe6358f2fd 100644
--- a/fs/fuse/dev_uring.c
+++ b/fs/fuse/dev_uring.c
@@ -19,6 +19,10 @@ MODULE_PARM_DESC(enable_uring,
"Enable uring userspace communication through uring.");
#endif
+struct fuse_uring_cmd_pdu {
+ struct fuse_ring_ent *ring_ent;
+};
+
/*
* Finalize a fuse request, then fetch and send the next entry, if available
*/
@@ -931,3 +935,100 @@ int fuse_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
return -EIOCBQUEUED;
}
+
+/*
+ * This prepares and sends the ring request in fuse-uring task context.
+ * User buffers are not mapped yet - the application does not have permission
+ * to write to it - this has to be executed in ring task context.
+ * XXX: Map and pin user paged and avoid this function.
+ */
+static void
+fuse_uring_send_req_in_task(struct io_uring_cmd *cmd,
+ unsigned int issue_flags)
+{
+ struct fuse_uring_cmd_pdu *pdu = (struct fuse_uring_cmd_pdu *)cmd->pdu;
+ struct fuse_ring_ent *ring_ent = pdu->ring_ent;
+ struct fuse_ring_queue *queue = ring_ent->queue;
+ int err;
+
+ BUILD_BUG_ON(sizeof(pdu) > sizeof(cmd->pdu));
+
+ err = fuse_uring_prepare_send(ring_ent);
+ if (err)
+ goto err;
+
+ io_uring_cmd_done(cmd, 0, 0, issue_flags);
+
+ spin_lock(&queue->lock);
+ ring_ent->state = FRRS_USERSPACE;
+ list_move(&ring_ent->list, &queue->ent_in_userspace);
+ spin_unlock(&queue->lock);
+ return;
+err:
+ fuse_uring_next_fuse_req(ring_ent, queue);
+}
+
+/* queue a fuse request and send it if a ring entry is available */
+int fuse_uring_queue_fuse_req(struct fuse_conn *fc, struct fuse_req *req)
+{
+ struct fuse_ring *ring = fc->ring;
+ struct fuse_ring_queue *queue;
+ int qid = 0;
+ struct fuse_ring_ent *ring_ent = NULL;
+ int res;
+
+ /*
+ * async requests are best handled on another core, the current
+ * core can do application/page handling, while the async request
+ * is handled on another core in userspace.
+ * For sync request the application has to wait - no processing, so
+ * the request should continue on the current core and avoid context
+ * switches.
+ * XXX This should be on the same numa node and not busy - is there
+ * a scheduler function available that could make this decision?
+ * It should also not persistently switch between cores - makes
+ * it hard for the scheduler.
+ */
+ qid = task_cpu(current);
+
+ if (WARN_ONCE(qid >= ring->nr_queues,
+ "Core number (%u) exceeds nr ueues (%zu)\n", qid,
+ ring->nr_queues))
+ qid = 0;
+
+ queue = ring->queues[qid];
+ if (WARN_ONCE(!queue, "Missing queue for qid %d\n", qid))
+ return -EINVAL;
+
+ spin_lock(&queue->lock);
+
+ if (unlikely(queue->stopped)) {
+ res = -ENOTCONN;
+ goto err_unlock;
+ }
+
+ list_add_tail(&req->list, &queue->fuse_req_queue);
+
+ if (!list_empty(&queue->ent_avail_queue)) {
+ ring_ent = list_first_entry(&queue->ent_avail_queue,
+ struct fuse_ring_ent, list);
+ list_del_init(&ring_ent->list);
+ fuse_uring_add_req_to_ring_ent(ring_ent, req);
+ }
+ spin_unlock(&queue->lock);
+
+ if (ring_ent) {
+ struct io_uring_cmd *cmd = ring_ent->cmd;
+ struct fuse_uring_cmd_pdu *pdu =
+ (struct fuse_uring_cmd_pdu *)cmd->pdu;
+
+ pdu->ring_ent = ring_ent;
+ io_uring_cmd_complete_in_task(cmd, fuse_uring_send_req_in_task);
+ }
+
+ return 0;
+
+err_unlock:
+ spin_unlock(&queue->lock);
+ return res;
+}
diff --git a/fs/fuse/dev_uring_i.h b/fs/fuse/dev_uring_i.h
index c19e439cd51316bdabdd16901659e97b2ff90875..4f5586684cb8fec3ddc825511cb6b935f5cf85d6 100644
--- a/fs/fuse/dev_uring_i.h
+++ b/fs/fuse/dev_uring_i.h
@@ -122,6 +122,7 @@ void fuse_uring_destruct(struct fuse_conn *fc);
void fuse_uring_stop_queues(struct fuse_ring *ring);
void fuse_uring_abort_end_requests(struct fuse_ring *ring);
int fuse_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags);
+int fuse_uring_queue_fuse_req(struct fuse_conn *fc, struct fuse_req *req);
static inline void fuse_uring_set_stopped_queues(struct fuse_ring *ring)
{
@@ -175,6 +176,12 @@ static inline void fuse_uring_abort(struct fuse_conn *fc)
static inline void fuse_uring_wait_stopped_queues(struct fuse_conn *fc)
{
}
+
+static inline int
+fuse_uring_queue_fuse_req(struct fuse_conn *fc, struct fuse_req *req)
+{
+ return -EPFNOSUPPORT;
+}
#endif /* CONFIG_FUSE_IO_URING */
#endif /* _FS_FUSE_DEV_URING_I_H */
--
2.43.0
