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From: santosh.shilimkar@oracle.com
To: Jason Gunthorpe <jgg@nvidia.com>,
	Danil Kipnis <danil.kipnis@cloud.ionos.com>,
	Doug Ledford <dledford@redhat.com>,
	Christoph Hellwig <hch@lst.de>,
	Jack Wang <jinpu.wang@cloud.ionos.com>,
	Keith Busch <kbusch@kernel.org>,
	linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
	Max Gurtovoy <mgurtovoy@nvidia.com>,
	netdev@vger.kernel.org, rds-devel@oss.oracle.com,
	Sagi Grimberg <sagi@grimberg.me>
Cc: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>,
	Leon Romanovsky <leonro@nvidia.com>
Subject: Re: [PATCH] RDMA: Add rdma_connect_locked()
Date: Mon, 26 Oct 2020 09:01:20 -0700	[thread overview]
Message-ID: <ed68ad93-602e-c617-87e4-a713856478a0@oracle.com> (raw)
In-Reply-To: <0-v1-75e124dbad74+b05-rdma_connect_locking_jgg@nvidia.com>



On 10/26/20 7:25 AM, 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.
> 
> Reported-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
> Fixes: 2a7cec538169 ("RDMA/cma: Fix locking for the RDMA_CM_CONNECT state"
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---

[....]

> 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
> 
For RDS part,
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

WARNING: multiple messages have this Message-ID (diff)
From: santosh.shilimkar@oracle.com
To: Jason Gunthorpe <jgg@nvidia.com>,
	Danil Kipnis <danil.kipnis@cloud.ionos.com>,
	Doug Ledford <dledford@redhat.com>,
	Christoph Hellwig <hch@lst.de>,
	Jack Wang <jinpu.wang@cloud.ionos.com>,
	Keith Busch <kbusch@kernel.org>,
	linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org,
	Max Gurtovoy <mgurtovoy@nvidia.com>,
	netdev@vger.kernel.org, rds-devel@oss.oracle.com,
	Sagi Grimberg <sagi@grimberg.me>
Cc: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>,
	Leon Romanovsky <leonro@nvidia.com>
Subject: Re: [PATCH] RDMA: Add rdma_connect_locked()
Date: Mon, 26 Oct 2020 09:01:20 -0700	[thread overview]
Message-ID: <ed68ad93-602e-c617-87e4-a713856478a0@oracle.com> (raw)
In-Reply-To: <0-v1-75e124dbad74+b05-rdma_connect_locking_jgg@nvidia.com>



On 10/26/20 7:25 AM, 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.
> 
> Reported-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
> Fixes: 2a7cec538169 ("RDMA/cma: Fix locking for the RDMA_CM_CONNECT state"
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---

[....]

> 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
> 
For RDS part,
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>

_______________________________________________
Linux-nvme mailing list
Linux-nvme@lists.infradead.org
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  reply	other threads:[~2020-10-26 16:02 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-26 14:25 [PATCH] RDMA: Add rdma_connect_locked() Jason Gunthorpe
2020-10-26 14:25 ` Jason Gunthorpe
2020-10-26 16:01 ` santosh.shilimkar [this message]
2020-10-26 16:01   ` santosh.shilimkar
2020-10-27  2:01 ` Chao Leng
2020-10-27  2:01   ` Chao Leng
2020-10-27 12:00   ` Jason Gunthorpe
2020-10-27 12:00     ` Jason Gunthorpe
2020-10-27  7:33 ` Jinpu Wang
2020-10-27  7:33   ` Jinpu Wang
2020-10-27  8:04 ` Christoph Hellwig
2020-10-27  8:04   ` Christoph Hellwig
2020-10-27 12:05 ` Guoqing Jiang
2020-10-27 12:05   ` Guoqing Jiang

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