Re: [PATCH 2/3] firmware: add offset to request_firmware_into_buf

From: Scott Branden <scott.branden@broadcom.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
	David Brown <david.brown@linaro.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
	Olof Johansson <olof@lixom.net>
Subject: Re: [PATCH 2/3] firmware: add offset to request_firmware_into_buf
Date: Wed, 31 Jul 2019 17:18:32 -0700	[thread overview]
Message-ID: <2f67db0a-27c3-d13c-bbe0-0af5edd4f0da@broadcom.com> (raw)
In-Reply-To: <20190524052258.GB28229@kroah.com>

Hi Greg,

I am now back from leave to continue this patch.  Comment below.

On 2019-05-23 10:22 p.m., Greg Kroah-Hartman wrote:
> On Thu, May 23, 2019 at 10:01:38PM -0700, Scott Branden wrote:
>> On 2019-05-23 9:54 a.m., Greg Kroah-Hartman wrote:
>>> On Thu, May 23, 2019 at 09:36:02AM -0700, Scott Branden wrote:
>>>> Hi Greg,
>>>>
>>>> On 2019-05-22 10:52 p.m., Greg Kroah-Hartman wrote:
>>>>> On Wed, May 22, 2019 at 07:51:12PM -0700, Scott Branden wrote:
>>>>>> Add offset to request_firmware_into_buf to allow for portions
>>>>>> of firmware file to be read into a buffer.  Necessary where firmware
>>>>>> needs to be loaded in portions from file in memory constrained systems.
>>>>>>
>>>>>> Signed-off-by: Scott Branden <scott.branden@broadcom.com>
>>>>>> ---
>>>>>>     drivers/base/firmware_loader/firmware.h |  5 +++
>>>>>>     drivers/base/firmware_loader/main.c     | 49 +++++++++++++++++--------
>>>>>>     include/linux/firmware.h                |  8 +++-
>>>>>>     3 files changed, 45 insertions(+), 17 deletions(-)
>>>>> No new firmware test for this new option?  How do we know it even works?
>>>> I was unaware there are existing firmware tests.  Please let me know where
>>>> these tests exists and I can add a test for this new option.
>>> tools/testing/selftests/firmware/
>> Unfortunately, there doesn't seem to be a test for the existing
>> request_firmware_into_buf api.
> Are you sure?  The test is for userspace functionality, there isn't
> kernel unit tests here.  You need to verify that you didn't break
> existing functionality as well as verify that your new functionality
> works.

I managed to figure out how to build and run 
tools/testing/selftest/firmware/fw_run_tests.sh

and my changes don't break existing functionality.

But, I find no use of request_firmware_into_buf in lib/test_firmware.c 
(triggered by fw_run_tests.sh).

Is there another test for request_firmware_into_buf?

>>>> We have tested this with a new driver in development which requires the
>>>> firmware file to be read in portions into memory.  I can add my tested-by
>>>> and others to the commit message if desired.
>>> I can't take new apis without an in-kernel user, you all know this...
>> OK, It will have to wait then as I was hoping to get this in before my
>> leave.
> Throwing new code over the wall and running away is a sure way to ensure
> that your code will be ignored :)
>
> thanks,
>
> greg k-h