Date: Mon, 13 Apr 2015 14:12:49 -0400
From: "ira.weiny" <ira.weiny@intel.com>
To: Michael Wang <yun.wang@profitbricks.com>
Cc: Roland Dreier <roland@kernel.org>, Sean Hefty <sean.hefty@intel.com>,
        Hal Rosenstock <hal.rosenstock@gmail.com>, linux-rdma@vger.kernel.org,
        linux-kernel@vger.kernel.org, Tom Tucker <tom@opengridcomputing.com>,
        Steve Wise <swise@opengridcomputing.com>,
        Hoang-Nam Nguyen <hnguyen@de.ibm.com>,
        Christoph Raisch <raisch@de.ibm.com>,
        Mike Marciniszyn <infinipath@intel.com>, Eli Cohen <eli@mellanox.com>,
        Faisal Latif <faisal.latif@intel.com>,
        Jack Morgenstein <jackm@dev.mellanox.co.il>,
        Or Gerlitz <ogerlitz@mellanox.com>, Haggai Eran <haggaie@mellanox.com>,
        Tom Talpey <tom@talpey.com>,
        Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
        Doug Ledford <dledford@redhat.com>
Subject: Re: [PATCH v3 04/28] IB/Verbs: Reform IB-core cm
Message-ID: <20150413181248.GA2464@phlsvsds.ph.intel.com>
References: <552BB470.4090407@profitbricks.com> <552BB552.1030905@profitbricks.com>
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On Mon, Apr 13, 2015 at 02:23:46PM +0200, Michael Wang wrote:
> 
> Use raw management helpers to reform IB-core cm.
> 
> Cc: Steve Wise <swise@opengridcomputing.com>
> Cc: Tom Talpey <tom@talpey.com>
> Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
> Cc: Doug Ledford <dledford@redhat.com>
> Cc: Ira Weiny <ira.weiny@intel.com>
> Cc: Sean Hefty <sean.hefty@intel.com>
> Signed-off-by: Michael Wang <yun.wang@profitbricks.com>
> ---
>  drivers/infiniband/core/cm.c | 22 +++++++++++++++++++---
>  1 file changed, 19 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
> index e28a494..50321fe 100644
> --- a/drivers/infiniband/core/cm.c
> +++ b/drivers/infiniband/core/cm.c
> @@ -3761,9 +3761,7 @@ static void cm_add_one(struct ib_device *ib_device)
>  	unsigned long flags;
>  	int ret;
>  	u8 i;
> -
> -	if (rdma_node_get_transport(ib_device->node_type) != RDMA_TRANSPORT_IB)
> -		return;
> +	int count = 0;

I'm ok with this as an intermediate patch but going forward if we are going to
have calls like 

static inline int cap_ib_cm_dev(struct ib_device *device)

Then I think we should have similar calls like

cap_ib_mad_dev(device)

Which eliminates the clean up below...

>  
>  	cm_dev = kzalloc(sizeof(*cm_dev) + sizeof(*port) *
>  			 ib_device->phys_port_cnt, GFP_KERNEL);
> @@ -3783,6 +3781,9 @@ static void cm_add_one(struct ib_device *ib_device)
>  
>  	set_bit(IB_MGMT_METHOD_SEND, reg_req.method_mask);
>  	for (i = 1; i <= ib_device->phys_port_cnt; i++) {
> +		if (!rdma_ib_or_iboe(ib_device, i))
> +			continue;
> +
>  		port = kzalloc(sizeof *port, GFP_KERNEL);
>  		if (!port)
>  			goto error1;
> @@ -3809,7 +3810,16 @@ static void cm_add_one(struct ib_device *ib_device)
>  		ret = ib_modify_port(ib_device, i, 0, &port_modify);
>  		if (ret)
>  			goto error3;
> +
> +		count++;
>  	}
> +
> +	if (!count) {
> +		device_unregister(cm_dev->device);
> +		kfree(cm_dev);
> +		return;

Here.

I worry about mistakes being made when we loop through only to find that none
of the ports support the feature and then we have to clean up.  As this is
initialization code I don't see any issue with looping through the ports 2
times and making the code cleaner.

This applies to the SA and CM modules as well.

However, in the ib_cm module you already have cap_ib_cm_dev(device) so you
should use it at the start of cm_add_one.

Ira

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