Merge branch 'devx-async' into k.o/for-next

Yishai Hadas says:

Enable DEVX asynchronous query commands

This series enables querying a DEVX object in an asynchronous mode.

The userspace application won't block when calling the firmware and it will be
able to get the response back once that it will be ready.

To enable the above functionality:

- DEVX asynchronous command completion FD object was introduced.
- The applicable file operations were implemented to enable using it by
  the user application.
- Query asynchronous method was added to the DEVX object, it will call the
  firmware asynchronously and manages the response on the given input FD.
- Hot unplug support was added for the FD to work properly upon
  unbind/disassociate.
- mlx5 core fence for asynchronous commands was implemented and used to
  prevent racing upon unbind/disassociate.

This branch is based on mlx5-next & v5.0-rc2 due to dependencies, from
git://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux

* branch 'devx-async':
  IB/mlx5: Implement DEVX hot unplug for async command FD
  IB/mlx5: Implement the file ops of DEVX async command FD
  IB/mlx5: Introduce async DEVX obj query API
  IB/mlx5: Introduce MLX5_IB_OBJECT_DEVX_ASYNC_CMD_FD

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 317 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
index bbf9a26d8fa6..12de63c63fa0 100644
--- a/drivers/infiniband/hw/mlx5/devx.c
+++ b/drivers/infiniband/hw/mlx5/devx.c
@@ -8,6 +8,7 @@
 #include <rdma/uverbs_types.h>
 #include <rdma/uverbs_ioctl.h>
 #include <rdma/mlx5_user_ioctl_cmds.h>
+#include <rdma/mlx5_user_ioctl_verbs.h>
 #include <rdma/ib_umem.h>
 #include <rdma/uverbs_std_types.h>
 #include <linux/mlx5/driver.h>
@@ -21,6 +22,16 @@ enum devx_obj_flags {
 	DEVX_OBJ_FLAGS_INDIRECT_MKEY = 1 << 0,
 };
 
+struct devx_async_data {
+	struct mlx5_ib_dev *mdev;
+	struct list_head list;
+	struct ib_uobject *fd_uobj;
+	struct mlx5_async_work cb_work;
+	u16 cmd_out_len;
+	/* must be last field in this structure */
+	struct mlx5_ib_uapi_devx_async_cmd_hdr hdr;
+};
+
 #define MLX5_MAX_DESTROY_INBOX_SIZE_DW MLX5_ST_SZ_DW(delete_fte_in)
 struct devx_obj {
 	struct mlx5_core_dev	*mdev;
@@ -1289,6 +1300,153 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_QUERY)(
 			      cmd_out, cmd_out_len);
 }
 
+struct devx_async_event_queue {
+	spinlock_t		lock;
+	wait_queue_head_t	poll_wait;
+	struct list_head	event_list;
+	atomic_t		bytes_in_use;
+	u8			is_destroyed:1;
+};
+
+struct devx_async_cmd_event_file {
+	struct ib_uobject		uobj;
+	struct devx_async_event_queue	ev_queue;
+	struct mlx5_async_ctx		async_ctx;
+};
+
+static void devx_init_event_queue(struct devx_async_event_queue *ev_queue)
+{
+	spin_lock_init(&ev_queue->lock);
+	INIT_LIST_HEAD(&ev_queue->event_list);
+	init_waitqueue_head(&ev_queue->poll_wait);
+	atomic_set(&ev_queue->bytes_in_use, 0);
+	ev_queue->is_destroyed = 0;
+}
+
+static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_ASYNC_CMD_FD_ALLOC)(
+	struct uverbs_attr_bundle *attrs)
+{
+	struct devx_async_cmd_event_file *ev_file;
+
+	struct ib_uobject *uobj = uverbs_attr_get_uobject(
+		attrs, MLX5_IB_ATTR_DEVX_ASYNC_CMD_FD_ALLOC_HANDLE);
+	struct mlx5_ib_dev *mdev = to_mdev(uobj->context->device);
+
+	ev_file = container_of(uobj, struct devx_async_cmd_event_file,
+			       uobj);
+	devx_init_event_queue(&ev_file->ev_queue);
+	mlx5_cmd_init_async_ctx(mdev->mdev, &ev_file->async_ctx);
+	return 0;
+}
+
+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;
+	unsigned long flags;
+
+	ev_file = container_of(fd_uobj, struct devx_async_cmd_event_file,
+			       uobj);
+	ev_queue = &ev_file->ev_queue;
+
+	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 */
+
+static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_ASYNC_QUERY)(
+	struct uverbs_attr_bundle *attrs)
+{
+	void *cmd_in = uverbs_attr_get_alloced_ptr(attrs,
+				MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_CMD_IN);
+	struct ib_uobject *uobj = uverbs_attr_get_uobject(
+				attrs,
+				MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_HANDLE);
+	u16 cmd_out_len;
+	struct mlx5_ib_ucontext *c = to_mucontext(uobj->context);
+	struct ib_uobject *fd_uobj;
+	int err;
+	int uid;
+	struct mlx5_ib_dev *mdev = to_mdev(uobj->context->device);
+	struct devx_async_cmd_event_file *ev_file;
+	struct devx_async_data *async_data;
+
+	uid = devx_get_uid(c, cmd_in);
+	if (uid < 0)
+		return uid;
+
+	if (!devx_is_obj_query_cmd(cmd_in))
+		return -EINVAL;
+
+	err = uverbs_get_const(&cmd_out_len, attrs,
+			       MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_OUT_LEN);
+	if (err)
+		return err;
+
+	if (!devx_is_valid_obj_id(uobj, cmd_in))
+		return -EINVAL;
+
+	fd_uobj = uverbs_attr_get_uobject(attrs,
+				MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_FD);
+	if (IS_ERR(fd_uobj))
+		return PTR_ERR(fd_uobj);
+
+	ev_file = container_of(fd_uobj, struct devx_async_cmd_event_file,
+			       uobj);
+
+	if (atomic_add_return(cmd_out_len, &ev_file->ev_queue.bytes_in_use) >
+			MAX_ASYNC_BYTES_IN_USE) {
+		atomic_sub(cmd_out_len, &ev_file->ev_queue.bytes_in_use);
+		return -EAGAIN;
+	}
+
+	async_data = kvzalloc(struct_size(async_data, hdr.out_data,
+					  cmd_out_len), GFP_KERNEL);
+	if (!async_data) {
+		err = -ENOMEM;
+		goto sub_bytes;
+	}
+
+	err = uverbs_copy_from(&async_data->hdr.wr_id, attrs,
+			       MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_WR_ID);
+	if (err)
+		goto free_async;
+
+	async_data->cmd_out_len = cmd_out_len;
+	async_data->mdev = mdev;
+	async_data->fd_uobj = fd_uobj;
+
+	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,
+				MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_CMD_IN),
+		    async_data->hdr.out_data,
+		    async_data->cmd_out_len,
+		    devx_query_callback, &async_data->cb_work);
+
+	if (err)
+		goto cb_err;
+
+	return 0;
+
+cb_err:
+	fput(fd_uobj->object);
+free_async:
+	kvfree(async_data);
+sub_bytes:
+	atomic_sub(cmd_out_len, &ev_file->ev_queue.bytes_in_use);
+	return err;
+}
+
 static int devx_umem_get(struct mlx5_ib_dev *dev, struct ib_ucontext *ucontext,
 			 struct uverbs_attr_bundle *attrs,
 			 struct devx_umem *obj)
@@ -1434,6 +1592,123 @@ static int devx_umem_cleanup(struct ib_uobject *uobject,
 	return 0;
 }
 
+static ssize_t devx_async_cmd_event_read(struct file *filp, char __user *buf,
+					 size_t count, loff_t *pos)
+{
+	struct devx_async_cmd_event_file *comp_ev_file = filp->private_data;
+	struct devx_async_event_queue *ev_queue = &comp_ev_file->ev_queue;
+	struct devx_async_data *event;
+	int ret = 0;
+	size_t eventsz;
+
+	spin_lock_irq(&ev_queue->lock);
+
+	while (list_empty(&ev_queue->event_list)) {
+		spin_unlock_irq(&ev_queue->lock);
+
+		if (filp->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+
+		if (wait_event_interruptible(
+			    ev_queue->poll_wait,
+			    (!list_empty(&ev_queue->event_list) ||
+			     ev_queue->is_destroyed))) {
+			return -ERESTARTSYS;
+		}
+
+		if (list_empty(&ev_queue->event_list) &&
+		    ev_queue->is_destroyed)
+			return -EIO;
+
+		spin_lock_irq(&ev_queue->lock);
+	}
+
+	event = list_entry(ev_queue->event_list.next,
+			   struct devx_async_data, list);
+	eventsz = event->cmd_out_len +
+			sizeof(struct mlx5_ib_uapi_devx_async_cmd_hdr);
+
+	if (eventsz > count) {
+		spin_unlock_irq(&ev_queue->lock);
+		return -ENOSPC;
+	}
+
+	list_del(ev_queue->event_list.next);
+	spin_unlock_irq(&ev_queue->lock);
+
+	if (copy_to_user(buf, &event->hdr, eventsz))
+		ret = -EFAULT;
+	else
+		ret = eventsz;
+
+	atomic_sub(event->cmd_out_len, &ev_queue->bytes_in_use);
+	kvfree(event);
+	return ret;
+}
+
+static int devx_async_cmd_event_close(struct inode *inode, struct file *filp)
+{
+	struct ib_uobject *uobj = filp->private_data;
+	struct devx_async_cmd_event_file *comp_ev_file = container_of(
+		uobj, struct devx_async_cmd_event_file, uobj);
+	struct devx_async_data *entry, *tmp;
+
+	spin_lock_irq(&comp_ev_file->ev_queue.lock);
+	list_for_each_entry_safe(entry, tmp,
+				 &comp_ev_file->ev_queue.event_list, list)
+		kvfree(entry);
+	spin_unlock_irq(&comp_ev_file->ev_queue.lock);
+
+	uverbs_close_fd(filp);
+	return 0;
+}
+
+static __poll_t devx_async_cmd_event_poll(struct file *filp,
+					      struct poll_table_struct *wait)
+{
+	struct devx_async_cmd_event_file *comp_ev_file = filp->private_data;
+	struct devx_async_event_queue *ev_queue = &comp_ev_file->ev_queue;
+	__poll_t pollflags = 0;
+
+	poll_wait(filp, &ev_queue->poll_wait, wait);
+
+	spin_lock_irq(&ev_queue->lock);
+	if (ev_queue->is_destroyed)
+		pollflags = EPOLLIN | EPOLLRDNORM | EPOLLRDHUP;
+	else if (!list_empty(&ev_queue->event_list))
+		pollflags = EPOLLIN | EPOLLRDNORM;
+	spin_unlock_irq(&ev_queue->lock);
+
+	return pollflags;
+}
+
+const struct file_operations devx_async_cmd_event_fops = {
+	.owner	 = THIS_MODULE,
+	.read	 = devx_async_cmd_event_read,
+	.poll    = devx_async_cmd_event_poll,
+	.release = devx_async_cmd_event_close,
+	.llseek	 = no_llseek,
+};
+
+static int devx_hot_unplug_async_cmd_event_file(struct ib_uobject *uobj,
+						   enum rdma_remove_reason why)
+{
+	struct devx_async_cmd_event_file *comp_ev_file =
+		container_of(uobj, struct devx_async_cmd_event_file,
+			     uobj);
+	struct devx_async_event_queue *ev_queue = &comp_ev_file->ev_queue;
+
+	spin_lock_irq(&ev_queue->lock);
+	ev_queue->is_destroyed = 1;
+	spin_unlock_irq(&ev_queue->lock);
+
+	if (why == RDMA_REMOVE_DRIVER_REMOVE)
+		wake_up_interruptible(&ev_queue->poll_wait);
+
+	mlx5_cmd_cleanup_async_ctx(&comp_ev_file->async_ctx);
+	return 0;
+};
+
 DECLARE_UVERBS_NAMED_METHOD(
 	MLX5_IB_METHOD_DEVX_UMEM_REG,
 	UVERBS_ATTR_IDR(MLX5_IB_ATTR_DEVX_UMEM_REG_HANDLE,
@@ -1544,6 +1819,27 @@ DECLARE_UVERBS_NAMED_METHOD(
 		UVERBS_ATTR_MIN_SIZE(MLX5_ST_SZ_BYTES(general_obj_out_cmd_hdr)),
 		UA_MANDATORY));
 
+DECLARE_UVERBS_NAMED_METHOD(
+	MLX5_IB_METHOD_DEVX_OBJ_ASYNC_QUERY,
+	UVERBS_ATTR_IDR(MLX5_IB_ATTR_DEVX_OBJ_QUERY_HANDLE,
+			UVERBS_IDR_ANY_OBJECT,
+			UVERBS_ACCESS_READ,
+			UA_MANDATORY),
+	UVERBS_ATTR_PTR_IN(
+		MLX5_IB_ATTR_DEVX_OBJ_QUERY_CMD_IN,
+		UVERBS_ATTR_MIN_SIZE(MLX5_ST_SZ_BYTES(general_obj_in_cmd_hdr)),
+		UA_MANDATORY,
+		UA_ALLOC_AND_COPY),
+	UVERBS_ATTR_CONST_IN(MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_OUT_LEN,
+		u16, UA_MANDATORY),
+	UVERBS_ATTR_FD(MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_FD,
+		MLX5_IB_OBJECT_DEVX_ASYNC_CMD_FD,
+		UVERBS_ACCESS_READ,
+		UA_MANDATORY),
+	UVERBS_ATTR_PTR_IN(MLX5_IB_ATTR_DEVX_OBJ_QUERY_ASYNC_WR_ID,
+		UVERBS_ATTR_TYPE(u64),
+		UA_MANDATORY));
+
 DECLARE_UVERBS_GLOBAL_METHODS(MLX5_IB_OBJECT_DEVX,
 			      &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_OTHER),
 			      &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_QUERY_UAR),
@@ -1554,13 +1850,30 @@ DECLARE_UVERBS_NAMED_OBJECT(MLX5_IB_OBJECT_DEVX_OBJ,
 			    &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_OBJ_CREATE),
 			    &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_OBJ_DESTROY),
 			    &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_OBJ_MODIFY),
-			    &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_OBJ_QUERY));
+			    &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_OBJ_QUERY),
+			    &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_OBJ_ASYNC_QUERY));
 
 DECLARE_UVERBS_NAMED_OBJECT(MLX5_IB_OBJECT_DEVX_UMEM,
 			    UVERBS_TYPE_ALLOC_IDR(devx_umem_cleanup),
 			    &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_UMEM_REG),
 			    &UVERBS_METHOD(MLX5_IB_METHOD_DEVX_UMEM_DEREG));
 
+
+DECLARE_UVERBS_NAMED_METHOD(
+	MLX5_IB_METHOD_DEVX_ASYNC_CMD_FD_ALLOC,
+	UVERBS_ATTR_FD(MLX5_IB_ATTR_DEVX_ASYNC_CMD_FD_ALLOC_HANDLE,
+			MLX5_IB_OBJECT_DEVX_ASYNC_CMD_FD,
+			UVERBS_ACCESS_NEW,
+			UA_MANDATORY));
+
+DECLARE_UVERBS_NAMED_OBJECT(
+	MLX5_IB_OBJECT_DEVX_ASYNC_CMD_FD,
+	UVERBS_TYPE_ALLOC_FD(sizeof(struct devx_async_cmd_event_file),
+			     devx_hot_unplug_async_cmd_event_file,
+			     &devx_async_cmd_event_fops, "[devx_async_cmd]",
+			     O_RDONLY),
+	&UVERBS_METHOD(MLX5_IB_METHOD_DEVX_ASYNC_CMD_FD_ALLOC));
+
 static bool devx_is_supported(struct ib_device *device)
 {
 	struct mlx5_ib_dev *dev = to_mdev(device);
@@ -1578,5 +1891,8 @@ const struct uapi_definition mlx5_ib_devx_defs[] = {
 	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(
 		MLX5_IB_OBJECT_DEVX_UMEM,
 		UAPI_DEF_IS_OBJ_SUPPORTED(devx_is_supported)),
+	UAPI_DEF_CHAIN_OBJ_TREE_NAMED(
+		MLX5_IB_OBJECT_DEVX_ASYNC_CMD_FD,
+		UAPI_DEF_IS_OBJ_SUPPORTED(devx_is_supported)),
 	{},
 };