From: Parav Pandit <parav@mellanox.com>
To: Bart Van Assche <Bart.VanAssche@sandisk.com>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "sebott@linux.vnet.ibm.com" <sebott@linux.vnet.ibm.com>,
        "linux@armlinux.org.uk" <linux@armlinux.org.uk>,
        "hpa@zytor.com" <hpa@zytor.com>, "mingo@redhat.com" <mingo@redhat.com>,
        "dwmw2@infradead.org" <dwmw2@infradead.org>,
        "bhelgaas@google.com" <bhelgaas@google.com>,
        "dledford@redhat.com" <dledford@redhat.com>,
        "benh@kernel.crashing.org" <benh@kernel.crashing.org>
Subject: RE: [PATCH 1/2] device: Stop requiring that struct device is embedded
 in struct pci_dev
Thread-Topic: [PATCH 1/2] device: Stop requiring that struct device is
 embedded in struct pci_dev
Thread-Index: AQHSltr7A9hsfT8RwUyV7gxEsYQ73qGIz5EAgAAC0hCAAAMDAIAAAKWQ
Date: Tue, 7 Mar 2017 05:20:54 +0000
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References: <20170307003549.3872-1-bart.vanassche@sandisk.com>
         <20170307003549.3872-2-bart.vanassche@sandisk.com>
         <20170307045236.GC3913@kroah.com>
         <VI1PR0502MB3008BEC2FB8747DDA40A10FCD12F0@VI1PR0502MB3008.eurprd05.prod.outlook.com>
 <1488863593.2997.3.camel@sandisk.com>
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Hi Bart,

> -----Original Message-----
> From: linux-rdma-owner@vger.kernel.org [mailto:linux-rdma-
> owner@vger.kernel.org] On Behalf Of Bart Van Assche
> Sent: Monday, March 6, 2017 11:13 PM
> To: Parav Pandit <parav@mellanox.com>; gregkh@linuxfoundation.org
> Cc: linux-kernel@vger.kernel.org; linux-rdma@vger.kernel.org;
> sebott@linux.vnet.ibm.com; linux@armlinux.org.uk; hpa@zytor.com;
> mingo@redhat.com; dwmw2@infradead.org; bhelgaas@google.com;
> dledford@redhat.com; benh@kernel.crashing.org
> Subject: Re: [PATCH 1/2] device: Stop requiring that struct device is
> embedded in struct pci_dev
> 
> On Tue, 2017-03-07 at 05:08 +0000, Parav Pandit wrote:
> > I replied with pseudo code in previous reply to Bart to bring back
> dma_device member in the ib_device.
> > dma_device member was already present in near past of few weeks.
> > It should be able to work using it without performance impact and without
> touching driver core layer like in this patch.
> 
> That's confusing and was a source of bugs and inconsistencies. We do not
> want two device structures in struct ib_device (struct device dev and struct
> device *dma_device).

device dev represents, dev structure of the ib_device.
While dma_device is for the actual device as you know.

If you look at net_device, 
It has device dev.
vendor drivers store pci_dev pointer and access device of pci_dev etc.
Every net_device driver has to do that.

Ib_device simplifies that work for ib stack by storing dma_device.
I think this is less confusing.

> 
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