mlx4: Do not allocate an extra (unneeded) CQE when creating a CQ.
The extra CQE can cause a huge waste of memory if requesting
a power-of-2 number of CQEs.
Leave create_cq for userspace CQs as before, to avoid breaking ABI.
(Handle this in separate libmlx4 patch)
Signed-off-by: Jack Morgenstein <[EMAIL PROTECTED]>
diff --git a/drivers/infiniband/hw/mlx4/cq.c b/drivers/infiniband/hw/mlx4/cq.c
index 8bf44da..8a1ccc4 100644
--- a/drivers/infiniband/hw/mlx4/cq.c
+++ b/drivers/infiniband/hw/mlx4/cq.c
@@ -108,7 +108,13 @@ struct ib_cq *mlx4_ib_create_cq(struct ib_device *ibdev,
int entries, int vector
if (!cq)
return ERR_PTR(-ENOMEM);
- entries = roundup_pow_of_two(entries + 1);
+ /* eliminate using extra CQE (for kernel space).
+ * For userspace, do in libmlx4, so that don't break ABI.
+ */
+ if (context)
+ entries = roundup_pow_of_two(entries + 1);
+ else
+ entries = roundup_pow_of_two(entries);
cq->ibcq.cqe = entries - 1;
buf_size = entries * sizeof (struct mlx4_cqe);
spin_lock_init(&cq->lock);
diff --git a/drivers/infiniband/hw/mlx4/main.c
b/drivers/infiniband/hw/mlx4/main.c
diff --git a/drivers/infiniband/hw/mlx4/mlx4_ib.h
b/drivers/infiniband/hw/mlx4/mlx4_ib.h
diff --git a/drivers/infiniband/hw/mlx4/qp.c b/drivers/infiniband/hw/mlx4/qp.c
diff --git a/drivers/net/mlx4/main.c b/drivers/net/mlx4/main.c
index 89b3f0b..d34b61b 100644
--- a/drivers/net/mlx4/main.c
+++ b/drivers/net/mlx4/main.c
@@ -141,12 +141,7 @@ static int mlx4_dev_cap(struct mlx4_dev *dev, struct
mlx4_dev_cap *dev_cap)
dev->caps.max_sq_desc_sz = dev_cap->max_sq_desc_sz;
dev->caps.max_rq_desc_sz = dev_cap->max_rq_desc_sz;
dev->caps.num_qp_per_mgm = MLX4_QP_PER_MGM;
- /*
- * Subtract 1 from the limit because we need to allocate a
- * spare CQE so the HCA HW can tell the difference between an
- * empty CQ and a full CQ.
- */
- dev->caps.max_cqes = dev_cap->max_cq_sz - 1;
+ dev->caps.max_cqes = dev_cap->max_cq_sz;
dev->caps.reserved_cqs = dev_cap->reserved_cqs;
dev->caps.reserved_eqs = dev_cap->reserved_eqs;
dev->caps.reserved_mtts = DIV_ROUND_UP(dev_cap->reserved_mtts,
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