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Commit c1395a2a authored by Haggai Eran's avatar Haggai Eran Committed by Roland Dreier
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IB/mlx5: Add function to read WQE from user-space 



Add a helper function mlx5_ib_read_user_wqe to read information from
user-space owned work queues.  The function will be used in a later
patch by the page-fault handling code in mlx5_ib.

Signed-off-by: default avatarHaggai Eran <haggaie@mellanox.com>

[ Add stub for ib_umem_copy_from() for CONFIG_INFINIBAND_USER_MEM=n
  - Roland ]

Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
parent c5d76f13

drivers/infiniband/hw/mlx5/mlx5_ib.h

+2 −0
Original line number Diff line number Diff line
@@ -503,6 +503,8 @@ int mlx5_ib_post_send(struct ib_qp *ibqp, struct ib_send_wr *wr, 
int mlx5_ib_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *wr,

		      struct ib_recv_wr **bad_wr);

void *mlx5_get_send_wqe(struct mlx5_ib_qp *qp, int n);

int mlx5_ib_read_user_wqe(struct mlx5_ib_qp *qp, int send, int wqe_index,

			  void *buffer, u32 length);

struct ib_cq *mlx5_ib_create_cq(struct ib_device *ibdev, int entries,

				int vector, struct ib_ucontext *context,

				struct ib_udata *udata);

drivers/infiniband/hw/mlx5/qp.c

+71 −0
Original line number Diff line number Diff line
@@ -101,6 +101,77 @@ void *mlx5_get_send_wqe(struct mlx5_ib_qp *qp, int n) 
	return get_wqe(qp, qp->sq.offset + (n << MLX5_IB_SQ_STRIDE));

}



/**

 * mlx5_ib_read_user_wqe() - Copy a user-space WQE to kernel space.

 *

 * @qp: QP to copy from.

 * @send: copy from the send queue when non-zero, use the receive queue

 *	  otherwise.

 * @wqe_index:  index to start copying from. For send work queues, the

 *		wqe_index is in units of MLX5_SEND_WQE_BB.

 *		For receive work queue, it is the number of work queue

 *		element in the queue.

 * @buffer: destination buffer.

 * @length: maximum number of bytes to copy.

 *

 * Copies at least a single WQE, but may copy more data.

 *

 * Return: the number of bytes copied, or an error code.

 */

int mlx5_ib_read_user_wqe(struct mlx5_ib_qp *qp, int send, int wqe_index,

			  void *buffer, u32 length)

{

	struct ib_device *ibdev = qp->ibqp.device;

	struct mlx5_ib_dev *dev = to_mdev(ibdev);

	struct mlx5_ib_wq *wq = send ? &qp->sq : &qp->rq;

	size_t offset;

	size_t wq_end;

	struct ib_umem *umem = qp->umem;

	u32 first_copy_length;

	int wqe_length;

	int ret;



	if (wq->wqe_cnt == 0) {

		mlx5_ib_dbg(dev, "mlx5_ib_read_user_wqe for a QP with wqe_cnt == 0. qp_type: 0x%x\n",

			    qp->ibqp.qp_type);

		return -EINVAL;

	}



	offset = wq->offset + ((wqe_index % wq->wqe_cnt) << wq->wqe_shift);

	wq_end = wq->offset + (wq->wqe_cnt << wq->wqe_shift);



	if (send && length < sizeof(struct mlx5_wqe_ctrl_seg))

		return -EINVAL;



	if (offset > umem->length ||

	    (send && offset + sizeof(struct mlx5_wqe_ctrl_seg) > umem->length))

		return -EINVAL;



	first_copy_length = min_t(u32, offset + length, wq_end) - offset;

	ret = ib_umem_copy_from(buffer, umem, offset, first_copy_length);

	if (ret)

		return ret;



	if (send) {

		struct mlx5_wqe_ctrl_seg *ctrl = buffer;

		int ds = be32_to_cpu(ctrl->qpn_ds) & MLX5_WQE_CTRL_DS_MASK;



		wqe_length = ds * MLX5_WQE_DS_UNITS;

	} else {

		wqe_length = 1 << wq->wqe_shift;

	}



	if (wqe_length <= first_copy_length)

		return first_copy_length;



	ret = ib_umem_copy_from(buffer + first_copy_length, umem, wq->offset,

				wqe_length - first_copy_length);

	if (ret)

		return ret;



	return wqe_length;

}



static void mlx5_ib_qp_event(struct mlx5_core_qp *qp, int type)

{

	struct ib_qp *ibqp = &to_mibqp(qp)->ibqp;

include/linux/mlx5/qp.h

+3 −0
Original line number Diff line number Diff line
@@ -189,6 +189,9 @@ struct mlx5_wqe_ctrl_seg { 
	__be32			imm;

};



#define MLX5_WQE_CTRL_DS_MASK 0x3f

#define MLX5_WQE_DS_UNITS 16



struct mlx5_wqe_xrc_seg {

	__be32			xrc_srqn;

	u8			rsvd[12];

include/rdma/ib_umem.h

+4 −1
Original line number Diff line number Diff line
@@ -98,7 +98,10 @@ static inline struct ib_umem *ib_umem_get(struct ib_ucontext *context, 
}

static inline void ib_umem_release(struct ib_umem *umem) { }

static inline int ib_umem_page_count(struct ib_umem *umem) { return 0; }



static inline int ib_umem_copy_from(void *dst, struct ib_umem *umem, size_t offset,

		      		    size_t length) {

	return -EINVAL;

}

#endif /* CONFIG_INFINIBAND_USER_MEM */



#endif /* IB_UMEM_H */