[rdma,v2] RDMA: Add rdma_connect_locked()

Message ID	0-v2-53c22d5c1405+33-rdma_connect_locking_jgg@nvidia.com (mailing list archive)
State	Accepted
Commit	53c22d5c1405aa0764142a97bbb65779e605023d
Delegated to:	Jason Gunthorpe
Headers	show Return-Path: <SRS0=adbP=EC=vger.kernel.org=linux-rdma-owner@kernel.org> TLS: TLSv1.2, AES256-SHA) id <B5f98109b0001>; Tue, 27 Oct 2020 20:20:43 +0800 From: Jason Gunthorpe <jgg@nvidia.com> To: <linux-rdma@vger.kernel.org> CC: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>, Christoph Hellwig <hch@lst.de>, Jack Wang <jinpu.wang@cloud.ionos.com>, Leon Romanovsky <leonro@nvidia.com>, Chao Leng <lengchao@huawei.com>, Santosh Shilimkar <santosh.shilimkar@oracle.com>, Keith Busch <kbusch@kernel.org>, <linux-nvme@lists.infradead.org>, Max Gurtovoy <mgurtovoy@nvidia.com>, <netdev@vger.kernel.org>, <rds-devel@oss.oracle.com>, Sagi Grimberg <sagi@grimberg.me> Subject: [PATCH rdma v2] RDMA: Add rdma_connect_locked() Date: Tue, 27 Oct 2020 09:20:36 -0300 Message-ID: <0-v2-53c22d5c1405+33-rdma_connect_locking_jgg@nvidia.com> Content-Transfer-Encoding: quoted-printable Content-Type: text/plain MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Precedence: bulk
Series	[rdma,v2] RDMA: Add rdma_connect_locked() \| expand [rdma,v2] RDMA: Add rdma_connect_locked()

Jason Gunthorpe Oct. 27, 2020, 12:20 p.m. UTC

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-v1-75e124dbad74+b05-rdma_connect_locking_jgg@nvidia.com
Reported-and-tested-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Fixes: 2a7cec538169 ("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>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/infiniband/core/cma.c            | 40 +++++++++++++++++++++---
 drivers/infiniband/ulp/iser/iser_verbs.c |  2 +-
 drivers/infiniband/ulp/rtrs/rtrs-clt.c   |  4 +--
 drivers/nvme/host/rdma.c                 |  4 +--
 include/rdma/rdma_cm.h                   | 14 ++-------
 net/rds/ib_cm.c                          |  5 +--
 6 files changed, 46 insertions(+), 23 deletions(-)

v2:
 - Remove extra code from nvme (Chao)
 - Fix long lines (CH)

I've applied this version to rdma-rc - expecting to get these ULPs unbroken for rc2
release

Thanks,
Jason

Max Gurtovoy Oct. 27, 2020, 1:06 p.m. UTC | #1

On 10/27/2020 2:20 PM, Jason Gunthorpe wrote:
> 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-v1-75e124dbad74+b05-rdma_connect_locking_jgg@nvidia.com
> Reported-and-tested-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
> Fixes: 2a7cec538169 ("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>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>   drivers/infiniband/core/cma.c            | 40 +++++++++++++++++++++---
>   drivers/infiniband/ulp/iser/iser_verbs.c |  2 +-
>   drivers/infiniband/ulp/rtrs/rtrs-clt.c   |  4 +--
>   drivers/nvme/host/rdma.c                 |  4 +--
>   include/rdma/rdma_cm.h                   | 14 ++-------
>   net/rds/ib_cm.c                          |  5 +--
>   6 files changed, 46 insertions(+), 23 deletions(-)
>
> v2:
>   - Remove extra code from nvme (Chao)
>   - Fix long lines (CH)
>
> I've applied this version to rdma-rc - expecting to get these ULPs unbroken for rc2
> release
>
> Thanks,
> Jason
>
iser and nvme/rdma looks good to me,

Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>

Leon Romanovsky Oct. 27, 2020, 1:19 p.m. UTC | #2

On Tue, Oct 27, 2020 at 09:20:36AM -0300, Jason Gunthorpe wrote:
> 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-v1-75e124dbad74+b05-rdma_connect_locking_jgg@nvidia.com
> Reported-and-tested-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
> Fixes: 2a7cec538169 ("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>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/infiniband/core/cma.c            | 40 +++++++++++++++++++++---
>  drivers/infiniband/ulp/iser/iser_verbs.c |  2 +-
>  drivers/infiniband/ulp/rtrs/rtrs-clt.c   |  4 +--
>  drivers/nvme/host/rdma.c                 |  4 +--
>  include/rdma/rdma_cm.h                   | 14 ++-------
>  net/rds/ib_cm.c                          |  5 +--
>  6 files changed, 46 insertions(+), 23 deletions(-)
>
> v2:
>  - Remove extra code from nvme (Chao)
>  - Fix long lines (CH)
>
> I've applied this version to rdma-rc - expecting to get these ULPs unbroken for rc2
> release
>
> Thanks,
> Jason
>
> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> index 7c2ab1f2fbea37..193c8902b9db26 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -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);
> @@ -4038,13 +4038,21 @@ static int cma_connect_iw(struct rdma_id_private *id_priv,
>  	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;

Not a big deal, but his label is not correct anymore.

Thanks

Jason Gunthorpe Oct. 27, 2020, 1:23 p.m. UTC | #3

On Tue, Oct 27, 2020 at 03:19:36PM +0200, Leon Romanovsky wrote:

> > +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;
> 
> Not a big deal, but his label is not correct anymore.

Oh, yep

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 193c8902b9db26..f58d19881524dc 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -4053,10 +4053,8 @@ int rdma_connect_locked(struct rdma_cm_id *id,
 		container_of(id, struct rdma_id_private, id);
 	int ret;
 
-	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;
@@ -4078,7 +4076,6 @@ int rdma_connect_locked(struct rdma_cm_id *id,
 	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);

Sagi Grimberg Oct. 27, 2020, 9:08 p.m. UTC | #4

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

Maor Gottlieb Oct. 28, 2020, 9:19 a.m. UTC | #5

On 10/27/2020 2:20 PM, Jason Gunthorpe wrote:
> 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-v1-75e124dbad74+b05-rdma_connect_locking_jgg@nvidia.com
> Reported-and-tested-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
> Fixes: 2a7cec538169 ("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>
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>   drivers/infiniband/core/cma.c            | 40 +++++++++++++++++++++---
>   drivers/infiniband/ulp/iser/iser_verbs.c |  2 +-
>   drivers/infiniband/ulp/rtrs/rtrs-clt.c   |  4 +--
>   drivers/nvme/host/rdma.c                 |  4 +--
>   include/rdma/rdma_cm.h                   | 14 ++-------
>   net/rds/ib_cm.c                          |  5 +--
>   6 files changed, 46 insertions(+), 23 deletions(-)
>
> v2:
>   - Remove extra code from nvme (Chao)
>   - Fix long lines (CH)
>
> I've applied this version to rdma-rc - expecting to get these ULPs unbroken for rc2
> release
>
> Thanks,
> Jason
>
> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> index 7c2ab1f2fbea37..193c8902b9db26 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -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);
> @@ -4038,13 +4038,21 @@ static int cma_connect_iw(struct rdma_id_private *id_priv,
>   	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);

You need to delete the mutex_unlock in success path too.
>   	if (!cma_comp_exch(id_priv, RDMA_CM_ROUTE_RESOLVED, RDMA_CM_CONNECT)) {
>   		ret = -EINVAL;
>   		goto err_unlock;
> @@ -4071,6 +4079,30 @@ int rdma_connect(struct rdma_cm_id *id, struct rdma_conn_param *conn_param)
>   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;
>   }
> diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c
> index 2f3ebc0a75d924..2bd18b00689341 100644
> --- a/drivers/infiniband/ulp/iser/iser_verbs.c
> +++ b/drivers/infiniband/ulp/iser/iser_verbs.c
> @@ -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;
> diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> index 776e89231c52f7..f298adc02acba2 100644
> --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> @@ -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;
>   }
> diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
> index aad829a2b50d0f..8bbc48cc45dc1d 100644
> --- a/drivers/nvme/host/rdma.c
> +++ b/drivers/nvme/host/rdma.c
> @@ -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;
>   	}
>   
> diff --git a/include/rdma/rdma_cm.h b/include/rdma/rdma_cm.h
> index c672ae1da26bb5..32a67af18415d6 100644
> --- a/include/rdma/rdma_cm.h
> +++ b/include/rdma/rdma_cm.h
> @@ -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);
> diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
> index 06603dd1c8aa38..b36b60668b1da9 100644
> --- a/net/rds/ib_cm.c
> +++ b/net/rds/ib_cm.c
> @@ -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

Jason Gunthorpe Oct. 28, 2020, 12:14 p.m. UTC | #6

On Wed, Oct 28, 2020 at 11:19:14AM +0200, Maor Gottlieb wrote:
> > +			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);
> 
> You need to delete the mutex_unlock in success path too.

Gaaaaah. Just goes to prove I shouldn't write patches with a child on
my lap :\

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index f58d19881524dc..a77750b8954db0 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -4072,7 +4072,6 @@ int rdma_connect_locked(struct rdma_cm_id *id,
 		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);

Thanks,
Jason

Maor Gottlieb Oct. 28, 2020, 1:31 p.m. UTC | #7

On 10/28/2020 2:14 PM, Jason Gunthorpe wrote:
> On Wed, Oct 28, 2020 at 11:19:14AM +0200, Maor Gottlieb wrote:
>>> +			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);
>> You need to delete the mutex_unlock in success path too.
> Gaaaaah. Just goes to prove I shouldn't write patches with a child on
> my lap :\
>
> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> index f58d19881524dc..a77750b8954db0 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -4072,7 +4072,6 @@ int rdma_connect_locked(struct rdma_cm_id *id,
>   		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);
>
> Thanks,
> Jason

Reviewed-by: Maor Gottlieb <maorg@nvidia.com>

[rdma,v2] RDMA: Add rdma_connect_locked()

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