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Commit e61ef241 authored by Roland Dreier's avatar Roland Dreier
Browse files

IB/mlx4: Make sure inline data segments don't cross a 64 byte boundary 



Inline data segments in send WQEs are not allowed to cross a 64 byte
boundary.  We use inline data segments to hold the UD headers for MLX
QPs (QP0 and QP1).  A send with GRH on QP1 will have a UD header that
is too big to fit in a single inline data segment without crossing a
64 byte boundary, so split the header into two inline data segments.

Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 5ae2a7a8

drivers/infiniband/hw/mlx4/qp.c

+39 −3
Original line number Diff line number Diff line
@@ -192,6 +192,8 @@ static int send_wqe_overhead(enum ib_qp_type type) 
	case IB_QPT_GSI:

		return sizeof (struct mlx4_wqe_ctrl_seg) +

			ALIGN(MLX4_IB_UD_HEADER_SIZE +

			      DIV_ROUND_UP(MLX4_IB_UD_HEADER_SIZE,

					   MLX4_INLINE_ALIGN) *

			      sizeof (struct mlx4_wqe_inline_seg),

			      sizeof (struct mlx4_wqe_data_seg)) +

			ALIGN(4 +
@@ -1049,6 +1051,7 @@ static int build_mlx_header(struct mlx4_ib_sqp *sqp, struct ib_send_wr *wr, 
	u16 pkey;

	int send_size;

	int header_size;

	int spc;

	int i;



	send_size = 0;
@@ -1124,10 +1127,43 @@ static int build_mlx_header(struct mlx4_ib_sqp *sqp, struct ib_send_wr *wr, 
		printk("\n");

	}



	/*

	 * Inline data segments may not cross a 64 byte boundary.  If

	 * our UD header is bigger than the space available up to the

	 * next 64 byte boundary in the WQE, use two inline data

	 * segments to hold the UD header.

	 */

	spc = MLX4_INLINE_ALIGN -

		((unsigned long) (inl + 1) & (MLX4_INLINE_ALIGN - 1));

	if (header_size <= spc) {

		inl->byte_count = cpu_to_be32(1 << 31 | header_size);

		memcpy(inl + 1, sqp->header_buf, header_size);

		i = 1;

	} else {

		inl->byte_count = cpu_to_be32(1 << 31 | spc);

		memcpy(inl + 1, sqp->header_buf, spc);



		inl = (void *) (inl + 1) + spc;

		memcpy(inl + 1, sqp->header_buf + spc, header_size - spc);

		/*

		 * Need a barrier here to make sure all the data is

		 * visible before the byte_count field is set.

		 * Otherwise the HCA prefetcher could grab the 64-byte

		 * chunk with this inline segment and get a valid (!=

		 * 0xffffffff) byte count but stale data, and end up

		 * generating a packet with bad headers.

		 *

		 * The first inline segment's byte_count field doesn't

		 * need a barrier, because it comes after a

		 * control/MLX segment and therefore is at an offset

		 * of 16 mod 64.

		 */

		wmb();

		inl->byte_count = cpu_to_be32(1 << 31 | (header_size - spc));

		i = 2;

	}



	return ALIGN(sizeof (struct mlx4_wqe_inline_seg) + header_size, 16);

	return ALIGN(i * sizeof (struct mlx4_wqe_inline_seg) + header_size, 16);

}



static int mlx4_wq_overflow(struct mlx4_ib_wq *wq, int nreq, struct ib_cq *ib_cq)

include/linux/mlx4/qp.h

+4 −0
Original line number Diff line number Diff line
@@ -269,6 +269,10 @@ struct mlx4_wqe_data_seg { 
	__be64			addr;

};



enum {

	MLX4_INLINE_ALIGN	= 64,

};



struct mlx4_wqe_inline_seg {

	__be32			byte_count;

};