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RDMA: Add rdma_connect_locked()

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There are two flows for handling RDMA_CM_EVENT_ROUTE_RESOLVED, either the
handler triggers a completion and another thread does rdma_connect() or
the handler directly calls rdma_connect().

In all cases rdma_connect() needs to hold the handler_mutex, but when
handler's are invoked this is already held by the core code. This causes
ULPs using the 2nd method to deadlock.

Provide a rdma_connect_locked() and have all ULPs call it from their
handlers.

Link: https://lore.kernel.org/r/0-v2-53c22d5c1405+33-rdma_connect_locking_jgg@nvidia.com
Reported-and-tested-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Fixes: 2a7cec5381 ("RDMA/cma: Fix locking for the RDMA_CM_CONNECT state")
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jason Gunthorpe 2020-10-26 11:25:49 -03:00
parent 7d66a71488
commit 071ba4cc55
6 changed files with 48 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
drivers/infiniband/core/cma.c
View File

@ -405,10 +405,10 @@ static int cma_comp_exch(struct rdma_id_private *id_priv,
/*
* The FSM uses a funny double locking where state is protected by both
* the handler_mutex and the spinlock. State is not allowed to change
* away from a handler_mutex protected value without also holding
* to/from a handler_mutex protected value without also holding
* handler_mutex.
*/
if (comp == RDMA_CM_CONNECT)
if (comp == RDMA_CM_CONNECT || exch == RDMA_CM_CONNECT)
lockdep_assert_held(&id_priv->handler_mutex);
spin_lock_irqsave(&id_priv->lock, flags);
@ -4038,17 +4038,23 @@ out:
return ret;
}
int rdma_connect(struct rdma_cm_id *id, struct rdma_conn_param *conn_param)
/**
* rdma_connect_locked - Initiate an active connection request.
* @id: Connection identifier to connect.
* @conn_param: Connection information used for connected QPs.
*
* Same as rdma_connect() but can only be called from the
* RDMA_CM_EVENT_ROUTE_RESOLVED handler callback.
*/
int rdma_connect_locked(struct rdma_cm_id *id,
struct rdma_conn_param *conn_param)
{
struct rdma_id_private *id_priv =
container_of(id, struct rdma_id_private, id);
int ret;
mutex_lock(&id_priv->handler_mutex);
if (!cma_comp_exch(id_priv, RDMA_CM_ROUTE_RESOLVED, RDMA_CM_CONNECT)) {
ret = -EINVAL;
goto err_unlock;
}
if (!cma_comp_exch(id_priv, RDMA_CM_ROUTE_RESOLVED, RDMA_CM_CONNECT))
return -EINVAL;
if (!id->qp) {
id_priv->qp_num = conn_param->qp_num;
@ -4066,11 +4072,33 @@ int rdma_connect(struct rdma_cm_id *id, struct rdma_conn_param *conn_param)
ret = -ENOSYS;
if (ret)
goto err_state;
mutex_unlock(&id_priv->handler_mutex);
return 0;
err_state:
cma_comp_exch(id_priv, RDMA_CM_CONNECT, RDMA_CM_ROUTE_RESOLVED);
err_unlock:
return ret;
}
EXPORT_SYMBOL(rdma_connect_locked);
/**
* rdma_connect - Initiate an active connection request.
* @id: Connection identifier to connect.
* @conn_param: Connection information used for connected QPs.
*
* Users must have resolved a route for the rdma_cm_id to connect with by having
* called rdma_resolve_route before calling this routine.
*
* This call will either connect to a remote QP or obtain remote QP information
* for unconnected rdma_cm_id's. The actual operation is based on the
* rdma_cm_id's port space.
*/
int rdma_connect(struct rdma_cm_id *id, struct rdma_conn_param *conn_param)
{
struct rdma_id_private *id_priv =
container_of(id, struct rdma_id_private, id);
int ret;
mutex_lock(&id_priv->handler_mutex);
ret = rdma_connect_locked(id, conn_param);
mutex_unlock(&id_priv->handler_mutex);
return ret;
}

2
drivers/infiniband/ulp/iser/iser_verbs.c
View File

@ -620,7 +620,7 @@ static void iser_route_handler(struct rdma_cm_id *cma_id)
conn_param.private_data = (void *)&req_hdr;
conn_param.private_data_len = sizeof(struct iser_cm_hdr);
ret = rdma_connect(cma_id, &conn_param);
ret = rdma_connect_locked(cma_id, &conn_param);
if (ret) {
iser_err("failure connecting: %d\n", ret);
goto failure;

4
drivers/infiniband/ulp/rtrs/rtrs-clt.c
View File

@ -1674,9 +1674,9 @@ static int rtrs_rdma_route_resolved(struct rtrs_clt_con *con)
uuid_copy(&msg.sess_uuid, &sess->s.uuid);
uuid_copy(&msg.paths_uuid, &clt->paths_uuid);
err = rdma_connect(con->c.cm_id, &param);
err = rdma_connect_locked(con->c.cm_id, &param);
if (err)
rtrs_err(clt, "rdma_connect(): %d\n", err);
rtrs_err(clt, "rdma_connect_locked(): %d\n", err);
return err;
}

4
drivers/nvme/host/rdma.c
View File

@ -1890,10 +1890,10 @@ static int nvme_rdma_route_resolved(struct nvme_rdma_queue *queue)
priv.hsqsize = cpu_to_le16(queue->ctrl->ctrl.sqsize);
}
ret = rdma_connect(queue->cm_id, &param);
ret = rdma_connect_locked(queue->cm_id, &param);
if (ret) {
dev_err(ctrl->ctrl.device,
"rdma_connect failed (%d).\n", ret);
"rdma_connect_locked failed (%d).\n", ret);
goto out_destroy_queue_ib;
}

14
include/rdma/rdma_cm.h
View File

@ -227,19 +227,9 @@ void rdma_destroy_qp(struct rdma_cm_id *id);
int rdma_init_qp_attr(struct rdma_cm_id *id, struct ib_qp_attr *qp_attr,
int *qp_attr_mask);
/**
* rdma_connect - Initiate an active connection request.
* @id: Connection identifier to connect.
* @conn_param: Connection information used for connected QPs.
*
* Users must have resolved a route for the rdma_cm_id to connect with
* by having called rdma_resolve_route before calling this routine.
*
* This call will either connect to a remote QP or obtain remote QP
* information for unconnected rdma_cm_id's. The actual operation is
* based on the rdma_cm_id's port space.
*/
int rdma_connect(struct rdma_cm_id *id, struct rdma_conn_param *conn_param);
int rdma_connect_locked(struct rdma_cm_id *id,
struct rdma_conn_param *conn_param);
int rdma_connect_ece(struct rdma_cm_id *id, struct rdma_conn_param *conn_param,
struct rdma_ucm_ece *ece);

5
net/rds/ib_cm.c
View File

@ -956,9 +956,10 @@ int rds_ib_cm_initiate_connect(struct rdma_cm_id *cm_id, bool isv6)
rds_ib_cm_fill_conn_param(conn, &conn_param, &dp,
conn->c_proposed_version,
UINT_MAX, UINT_MAX, isv6);
ret = rdma_connect(cm_id, &conn_param);
ret = rdma_connect_locked(cm_id, &conn_param);
if (ret)
rds_ib_conn_error(conn, "rdma_connect failed (%d)\n", ret);
rds_ib_conn_error(conn, "rdma_connect_locked failed (%d)\n",
ret);
out:
/* Beware - returning non-zero tells the rdma_cm to destroy