lkml.org 
[lkml]   [2017]   [Jun]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH] i2c: ismt: fix wrong device address when unmap the data buffer
On Mon, Jun 12, 2017 at 1:19 PM, Peter Rosin <peda@axentia.se> wrote:
> On 2017-06-12 11:38, Andy Shevchenko wrote:
>> On Mon, Jun 12, 2017 at 12:28 PM, Peter Rosin <peda@axentia.se> wrote:
>>> On 2017-06-12 11:11, Andy Shevchenko wrote:
>>>> On Mon, Jun 12, 2017 at 6:42 AM, Song liwei <liwei.song@windriver.com> wrote:
>>>>> From: Liwei Song <liwei.song@windriver.com>
>>
>>>>> After finished I2C block read/write, when unmap the data buffer,
>>>>> a wrong device address was pass to dma_unmap_single(),
>>
>>>>> the right
>>>>> device address should be "dev" not "&adap->dev", the relation is
>>>>> *(&adap->dev) == dev.
>>>>
>>>> This is confusing. You are telling that there are two copies of struct
>>>> device here?
>>>
>>> Yes, there are two copies.
>>
>> No, there is not. See below.
>
> What I meant was that there are the struct device in pci_dev->dev and the
> struct device in adap->dev. That seems like two copies of struct device
> to me.

They are not copies. That's my point.

> I didn't mean that they are copies in the sense that they have the
> same content, but in the sense that they are both struct device.
>
> I guess we can argue ourselves blue over this point.

See above.

>> There are two struct devices,
>
> Hmm, two struct devices, I seem to recall that from somewhere... :-)

Okay, it's possible bad wording from my side.

>> one is a real PCI device, which
>> represents actual device what *does* DMA.
>> This struct should be used according to DMA API.

> When you put it like that, it's obvious that the patch is correct.

I agreed with this in the first place! See my first reply.

> I had
> this feeling that little thought had gone into the choice to pick "dev"
> over "&adap->dev", that's all.

As I said, my concern is the commit message to the change which is
totally confusing.

--
With Best Regards,
Andy Shevchenko

\
 
 \ /
  Last update: 2017-06-12 12:29    [W:0.064 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site