linux-kernel - Re: [PATCH v4 0/3] request_firmware() into pre-allocated buffers

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Message-ID: <CAJOFmgyZ-fd=Wn6fu1BbLYhchmd5YuqiHsdWV_bOyskwvq=N_A@mail.gmail.com>
Date:	Tue, 7 Jun 2016 09:47:01 -0700
From:	Stephen Boyd <stephen.boyd@...aro.org>
To:	Russell King - ARM Linux <linux@...linux.org.uk>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Ming Lei <ming.lei@...onical.com>,
	Vikram Mulukutla <markivx@...eaurora.org>,
	Mark Brown <broonie@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Mimi Zohar <zohar@...ux.vnet.ibm.com>,
	linux-arm@...ts.infradead.org
Subject: Re: [PATCH v4 0/3] request_firmware() into pre-allocated buffers

Ah sorry, I seem to have missed updating that one place (it was in
multiple places). I'll resend properly.

On 7 June 2016 at 01:45, Russell King - ARM Linux <linux@...linux.org.uk> wrote:
> And you're still doing it, after I've already pointed out that you
> posted these to linux-arm and not linux-arm-kernel.  By posting them
> to the wrong list, you are preventing proper review of these patches,
> so really these should not be merged until you've corrected that.
>
> On Tue, Jun 07, 2016 at 01:35:34AM -0700, Stephen Boyd wrote:
>> Some systems are memory constrained but they need to load very
>> large firmwares. The firmware subsystem allows drivers to request
>> this firmware be loaded from the filesystem, but this requires
>> that the entire firmware be loaded into kernel memory first
>> before it's provided to the driver. This can lead to a situation
>> where we map the firmware twice, once to load the firmware into
>> kernel memory and once to copy the firmware into the final
>> resting place.
>>
>> This design creates needless memory pressure and delays loading
>> because we have to copy from kernel memory to somewhere else.
>> This patch sets adds support to the request firmware API to load the
>> firmware directly into a pre-allocated buffer, skipping the intermediate
>> copying step and alleviating memory pressure during firmware loading.
>> The drawback is that we can't use the firmware caching feature because
>> the memory for the firmware cache is not managed by the firmware
>> layer.
>>
>> Patches based on v4.7-rc1.
>>
>> Changes since v3:
>>  * Rebased onto v4.7-rc1
>>  * Renamed enum per Mimi's comment
>>
>> Changes since v2:
>>  * Dropped DMA API changes and moved to dma coherent APIs per Catalin's
>>    suggestions
>>  * Reworked to request firmware directly into any pre-allocated buffer
>>  * Split off cleanup patch into patch #1 to ease review
>>  * Added file reading enum for reading firmware directly into buffer
>>
>> Changes since v1:
>>  * Rebased onto v4.6-rc1 (large conflicts due to movement of code from Mimi)
>>  * Added some CONFIG_HAS_DMA ifdefs around code that's using DMA ops
>>
>>
>> Stephen Boyd (2):
>>   firmware: Consolidate kmap/read/write logic
>>   firmware: Support loading into a pre-allocated buffer
>>
>> Vikram Mulukutla (1):
>>   firmware: Provide infrastructure to make fw caching optional
>>
>>  drivers/base/firmware_class.c | 183 +++++++++++++++++++++++++++++-------------
>>  fs/exec.c                     |   9 ++-
>>  include/linux/firmware.h      |   8 ++
>>  include/linux/fs.h            |   1 +
>>  4 files changed, 142 insertions(+), 59 deletions(-)
>>
>> --
>> 2.9.0-rc1
>>
>>
>> _______________________________________________
>> linux-arm mailing list
>> linux-arm@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm
>
> --
> RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
> FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
> according to speedtest.net.

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