RDMA/mlx5: Simplify devx async commands

With the new FD structure the async commands do not need to hold any
references while running. The existing mlx5_cmd_exec_cb() and
mlx5_cmd_cleanup_async_ctx() provide enough synchronization to ensure
that all outstanding commands are completed before the uobject can be
destructed.

Remove the now confusing get_file() and the type erasure of the
devx_async_cmd_event_file.

Link: https://lore.kernel.org/r/1578504126-9400-4-git-send-email-yishaih@mellanox.com
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
index 02125d82b96df48265daa8c1d6ad8d0afcb394e6..7bb91d24d3946c0a21e0da72434fa6aec21ca745 100644 (file)
--- a/drivers/infiniband/hw/mlx5/devx.c
+++ b/drivers/infiniband/hw/mlx5/devx.c
@@ -30,7 +30,7 @@ enum devx_obj_flags {
 struct devx_async_data {
        struct mlx5_ib_dev *mdev;
        struct list_head list;
-       struct ib_uobject *fd_uobj;
+       struct devx_async_cmd_event_file *ev_file;
        struct mlx5_async_work cb_work;
        u16 cmd_out_len;
        /* must be last field in this structure */
@@ -1673,21 +1673,20 @@ static void devx_query_callback(int status, struct mlx5_async_work *context)
 {
        struct devx_async_data *async_data =
                container_of(context, struct devx_async_data, cb_work);
-       struct ib_uobject *fd_uobj = async_data->fd_uobj;
-       struct devx_async_cmd_event_file *ev_file;
-       struct devx_async_event_queue *ev_queue;
+       struct devx_async_cmd_event_file *ev_file = async_data->ev_file;
+       struct devx_async_event_queue *ev_queue = &ev_file->ev_queue;
        unsigned long flags;
 
-       ev_file = container_of(fd_uobj, struct devx_async_cmd_event_file,
-                              uobj);
-       ev_queue = &ev_file->ev_queue;
-
+       /*
+        * Note that if the struct devx_async_cmd_event_file uobj begins to be
+        * destroyed it will block at mlx5_cmd_cleanup_async_ctx() until this
+        * routine returns, ensuring that it always remains valid here.
+        */
        spin_lock_irqsave(&ev_queue->lock, flags);
        list_add_tail(&async_data->list, &ev_queue->event_list);
        spin_unlock_irqrestore(&ev_queue->lock, flags);
 
        wake_up_interruptible(&ev_queue->poll_wait);
-       fput(fd_uobj->object);
 }
 
 #define MAX_ASYNC_BYTES_IN_USE (1024 * 1024) /* 1MB */
@@ -1756,9 +1755,8 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_ASYNC_QUERY)(
 
        async_data->cmd_out_len = cmd_out_len;
        async_data->mdev = mdev;
-       async_data->fd_uobj = fd_uobj;
+       async_data->ev_file = ev_file;
 
-       get_file(fd_uobj->object);
        MLX5_SET(general_obj_in_cmd_hdr, cmd_in, uid, uid);
        err = mlx5_cmd_exec_cb(&ev_file->async_ctx, cmd_in,
                    uverbs_attr_get_len(attrs,
@@ -1768,12 +1766,10 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_ASYNC_QUERY)(
                    devx_query_callback, &async_data->cb_work);
 
        if (err)
-               goto cb_err;
+               goto free_async;
 
        return 0;
 
-cb_err:
-       fput(fd_uobj->object);
 free_async:
        kvfree(async_data);
 sub_bytes: