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

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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: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Roland Dreier 2007-06-18 09:23:47 -07:00
parent 5ae2a7a836
commit e61ef2416b
2 changed files with 43 additions and 3 deletions
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42
drivers/infiniband/hw/mlx4/qp.c
View file

@ -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");
}
inl->byte_count = cpu_to_be32(1 << 31 | header_size);
memcpy(inl + 1, sqp->header_buf, header_size);
/*
* 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);
return ALIGN(sizeof (struct mlx4_wqe_inline_seg) + header_size, 16);
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(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)

4
include/linux/mlx4/qp.h
View file

@ -269,6 +269,10 @@ struct mlx4_wqe_data_seg {
__be64 addr;
};
enum {
MLX4_INLINE_ALIGN = 64,
};
struct mlx4_wqe_inline_seg {
__be32 byte_count;
};