RDMA/mlx5: Delete device resource mutex that didn't protect anything

The dev->devr.mutex was intended to protect GSI QP pointer change in the
struct mlx5_ib_port_resources when it is accessed from the
pkey_change_work. However that pointer isn't changed during the runtime
and once IB/core adds MAD, it stays stable.

Link: https://lore.kernel.org/r/6e338c561033df20d92e1371fc6a7a0d93aad945.1627040189.git.leonro@nvidia.com
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/hw/mlx5/gsi.c b/drivers/infiniband/hw/mlx5/gsi.c
index 7fcad91..e549d6f 100644 (file)
--- a/drivers/infiniband/hw/mlx5/gsi.c
+++ b/drivers/infiniband/hw/mlx5/gsi.c
@@ -116,8 +116,6 @@ int mlx5_ib_create_gsi(struct ib_pd *pd, struct mlx5_ib_qp *mqp,
                goto err_free_tx;
        }
 
-       mutex_lock(&dev->devr.mutex);
-
        if (dev->devr.ports[port_num - 1].gsi) {
                mlx5_ib_warn(dev, "GSI QP already exists on port %d\n",
                             port_num);
@@ -167,15 +165,11 @@ int mlx5_ib_create_gsi(struct ib_pd *pd, struct mlx5_ib_qp *mqp,
        INIT_LIST_HEAD(&gsi->rx_qp->sig_mrs);
 
        dev->devr.ports[attr->port_num - 1].gsi = gsi;
-
-       mutex_unlock(&dev->devr.mutex);
-
        return 0;
 
 err_destroy_cq:
        ib_free_cq(gsi->cq);
 err_free_wrs:
-       mutex_unlock(&dev->devr.mutex);
        kfree(gsi->outstanding_wrs);
 err_free_tx:
        kfree(gsi->tx_qps);
@@ -190,16 +184,13 @@ int mlx5_ib_destroy_gsi(struct mlx5_ib_qp *mqp)
        int qp_index;
        int ret;
 
-       mutex_lock(&dev->devr.mutex);
        ret = mlx5_ib_destroy_qp(gsi->rx_qp, NULL);
        if (ret) {
                mlx5_ib_warn(dev, "unable to destroy hardware GSI QP. error %d\n",
                             ret);
-               mutex_unlock(&dev->devr.mutex);
                return ret;
        }
        dev->devr.ports[port_num - 1].gsi = NULL;
-       mutex_unlock(&dev->devr.mutex);
        gsi->rx_qp = NULL;
 
        for (qp_index = 0; qp_index < gsi->num_qps; ++qp_index) {
@@ -339,23 +330,13 @@ err_destroy_qp:
        WARN_ON_ONCE(qp);
 }
 
-static void setup_qps(struct mlx5_ib_gsi_qp *gsi)
-{
-       struct mlx5_ib_dev *dev = to_mdev(gsi->rx_qp->device);
-       u16 qp_index;
-
-       mutex_lock(&dev->devr.mutex);
-       for (qp_index = 0; qp_index < gsi->num_qps; ++qp_index)
-               setup_qp(gsi, qp_index);
-       mutex_unlock(&dev->devr.mutex);
-}
-
 int mlx5_ib_gsi_modify_qp(struct ib_qp *qp, struct ib_qp_attr *attr,
                          int attr_mask)
 {
        struct mlx5_ib_dev *dev = to_mdev(qp->device);
        struct mlx5_ib_qp *mqp = to_mqp(qp);
        struct mlx5_ib_gsi_qp *gsi = &mqp->gsi;
+       u16 qp_index;
        int ret;
 
        mlx5_ib_dbg(dev, "modifying GSI QP to state %d\n", attr->qp_state);
@@ -366,8 +347,11 @@ int mlx5_ib_gsi_modify_qp(struct ib_qp *qp, struct ib_qp_attr *attr,
                return ret;
        }
 
-       if (to_mqp(gsi->rx_qp)->state == IB_QPS_RTS)
-               setup_qps(gsi);
+       if (to_mqp(gsi->rx_qp)->state != IB_QPS_RTS)
+               return 0;
+
+       for (qp_index = 0; qp_index < gsi->num_qps; ++qp_index)
+               setup_qp(gsi, qp_index);
        return 0;
 }
 
@@ -511,8 +495,8 @@ int mlx5_ib_gsi_post_recv(struct ib_qp *qp, const struct ib_recv_wr *wr,
 
 void mlx5_ib_gsi_pkey_change(struct mlx5_ib_gsi_qp *gsi)
 {
-       if (!gsi)
-               return;
+       u16 qp_index;
 
-       setup_qps(gsi);
+       for (qp_index = 0; qp_index < gsi->num_qps; ++qp_index)
+               setup_qp(gsi, qp_index);
 }

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index d2b9cba..c00c56d 100644 (file)
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -2501,6 +2501,13 @@ static void pkey_change_handler(struct work_struct *work)
                container_of(work, struct mlx5_ib_port_resources,
                             pkey_change_work);
 
+       if (!ports->gsi)
+               /*
+                * We got this event before device was fully configured
+                * and MAD registration code wasn't called/finished yet.
+                */
+               return;
+
        mlx5_ib_gsi_pkey_change(ports->gsi);
 }
 
@@ -2795,8 +2802,6 @@ static int mlx5_ib_dev_res_init(struct mlx5_ib_dev *dev)
        if (!MLX5_CAP_GEN(dev->mdev, xrc))
                return -EOPNOTSUPP;
 
-       mutex_init(&devr->mutex);
-
        devr->p0 = rdma_zalloc_drv_obj(ibdev, ib_pd);
        if (!devr->p0)
                return -ENOMEM;

diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 585fb00..0aa19cd 100644 (file)
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -795,8 +795,6 @@ struct mlx5_ib_resources {
        struct ib_srq   *s0;
        struct ib_srq   *s1;
        struct mlx5_ib_port_resources ports[2];
-       /* Protects changes to the port resources */
-       struct mutex    mutex;
 };
 
 struct mlx5_ib_counters {