From: Anup Patel <anup.patel@broadcom.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S . Miller" <davem@davemloft.net>,
Jassi Brar <jassisinghbrar@gmail.com>,
Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
Jon Mason <jonmason@broadcom.com>,
Rob Rice <rob.rice@broadcom.com>,
BCM Kernel Feedback <bcm-kernel-feedback-list@broadcom.com>,
"dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
Device Tree <devicetree@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-crypto@vger.kernel.org,
linux-raid <linux-raid@vger.kernel.org>
Subject: Re: [PATCH v2 2/5] async_tx: Handle DMA devices having support for fewer PQ coefficients
Date: Thu, 9 Feb 2017 14:59:35 +0530 [thread overview]
Message-ID: <CAALAos-ua6hVpUqjnJSQ=ysSOKrN67toiT3J808uHC4A_ZV3mg@mail.gmail.com> (raw)
In-Reply-To: <CAPcyv4iFJXxvJFrUs2jtwP9GX5NcJ8LiEDHeZ5b1fwjCAToe5w@mail.gmail.com>
On Wed, Feb 8, 2017 at 9:54 PM, Dan Williams <dan.j.williams@intel.com> wrote:
> On Wed, Feb 8, 2017 at 12:57 AM, Anup Patel <anup.patel@broadcom.com> wrote:
>> On Tue, Feb 7, 2017 at 11:46 PM, Dan Williams <dan.j.williams@intel.com> wrote:
>>> On Tue, Feb 7, 2017 at 1:02 AM, Anup Patel <anup.patel@broadcom.com> wrote:
>>>> On Tue, Feb 7, 2017 at 1:57 PM, Dan Williams <dan.j.williams@intel.com> wrote:
>>>>> On Tue, Feb 7, 2017 at 12:16 AM, Anup Patel <anup.patel@broadcom.com> wrote:
>>>>>> The DMAENGINE framework assumes that if PQ offload is supported by a
>>>>>> DMA device then all 256 PQ coefficients are supported. This assumption
>>>>>> does not hold anymore because we now have BCM-SBA-RAID offload engine
>>>>>> which supports PQ offload with limited number of PQ coefficients.
>>>>>>
>>>>>> This patch extends async_tx APIs to handle DMA devices with support
>>>>>> for fewer PQ coefficients.
>>>>>>
>>>>>> Signed-off-by: Anup Patel <anup.patel@broadcom.com>
>>>>>> Reviewed-by: Scott Branden <scott.branden@broadcom.com>
>>>>>
>>>>> I don't like this approach. Define an interface for md to query the
>>>>> offload engine once at the beginning of time. We should not be adding
>>>>> any new extensions to async_tx.
>>>>
>>>> Even if we do capability checks in Linux MD, we still need a way
>>>> for DMAENGINE drivers to advertise number of PQ coefficients
>>>> handled by the HW.
>>>>
>>>> I agree capability checks should be done once in Linux MD but I don't
>>>> see why this has to be part of BCM-SBA-RAID driver patches. We need
>>>> separate patchsets to address limitations of async_tx framework.
>>>
>>> Right, separate enabling before we pile on new hardware support to a
>>> known broken framework.
>>
>> Linux Async Tx not broken framework. The issue is:
>> 1. Its not complete enough
>> 2. Its not optimized for very high through-put offload engines
>
> I'm not understanding your point. I'm nak'ing this change to add yet
> more per-transaction capability checking to async_tx. I don't like the
> DMA_HAS_FEWER_PQ_COEF flag, especially since it is equal to
> DMA_HAS_PQ_CONTINUE. I'm not asking for all of async_tx's problems to
> be fixed before this new hardware support, I'm simply saying we should
> start the process of moving offload-engine capability checking to the
> raid code.
The DMA_HAS_FEWER_PQ_COEF is not equal to
DMA_HAS_PQ_CONTINUE.
I will try to drop this patch and take care of unsupported PQ
coefficients in BCM-SBA-RAID driver itself even if this means
doing some computations in BCM-SBA-RAID driver itself.
Regards,
Anup
next prev parent reply other threads:[~2017-02-09 9:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-07 8:16 [PATCH v2 0/5] Broadcom SBA RAID support Anup Patel
2017-02-07 8:16 ` [PATCH v2 1/5] lib/raid6: Add log-of-2 table for RAID6 HW requiring disk position Anup Patel
2017-02-07 8:16 ` [PATCH v2 2/5] async_tx: Handle DMA devices having support for fewer PQ coefficients Anup Patel
2017-02-07 8:27 ` Dan Williams
2017-02-07 9:02 ` Anup Patel
2017-02-07 16:42 ` Vinod Koul
2017-02-08 6:37 ` Anup Patel
2017-02-07 18:16 ` Dan Williams
2017-02-08 8:57 ` Anup Patel
2017-02-08 16:24 ` Dan Williams
2017-02-09 9:29 ` Anup Patel [this message]
2017-02-09 16:44 ` Dan Williams
2017-02-10 3:24 ` Anup Patel
2017-02-07 8:16 ` [PATCH v2 3/5] async_tx: Fix DMA_PREP_FENCE usage in do_async_gen_syndrome() Anup Patel
2017-02-07 8:16 ` [PATCH v2 4/5] dmaengine: Add Broadcom SBA RAID driver Anup Patel
2017-02-07 8:16 ` [PATCH v2 5/5] dt-bindings: Add DT bindings document for " Anup Patel
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