From: Dan Williams <dan.j.williams@intel.com> To: Anup Patel <anup.patel@broadcom.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 08:44:02 -0800 [thread overview] Message-ID: <CAPcyv4gDq+our1+sAPShBru-qvebo+Zvk0crgSUNXucHGQwZ1Q@mail.gmail.com> (raw) In-Reply-To: <CAALAos-ua6hVpUqjnJSQ=ysSOKrN67toiT3J808uHC4A_ZV3mg@mail.gmail.com> On Thu, Feb 9, 2017 at 1:29 AM, Anup Patel <anup.patel@broadcom.com> wrote: > 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. #define DMA_HAS_PQ_CONTINUE (1 << 15 #define DMA_HAS_FEWER_PQ_COEF (1 << 15) > 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. That should be nak'd as well, please do capability detection in a routine that is common to all raid engines.
WARNING: multiple messages have this Message-ID (diff)
From: dan.j.williams@intel.com (Dan Williams) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 2/5] async_tx: Handle DMA devices having support for fewer PQ coefficients Date: Thu, 9 Feb 2017 08:44:02 -0800 [thread overview] Message-ID: <CAPcyv4gDq+our1+sAPShBru-qvebo+Zvk0crgSUNXucHGQwZ1Q@mail.gmail.com> (raw) In-Reply-To: <CAALAos-ua6hVpUqjnJSQ=ysSOKrN67toiT3J808uHC4A_ZV3mg@mail.gmail.com> On Thu, Feb 9, 2017 at 1:29 AM, Anup Patel <anup.patel@broadcom.com> wrote: > 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. #define DMA_HAS_PQ_CONTINUE (1 << 15 #define DMA_HAS_FEWER_PQ_COEF (1 << 15) > 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. That should be nak'd as well, please do capability detection in a routine that is common to all raid engines.
next prev parent reply other threads:[~2017-02-09 16:44 UTC|newest] Thread overview: 44+ 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 ` 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 ` Anup Patel [not found] ` <1486455406-11202-1-git-send-email-anup.patel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org> 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 8:16 ` Anup Patel 2017-02-07 8:16 ` Anup Patel 2017-02-07 8:27 ` Dan Williams 2017-02-07 8:27 ` Dan Williams 2017-02-07 8:27 ` Dan Williams 2017-02-07 9:02 ` Anup Patel 2017-02-07 9:02 ` Anup Patel 2017-02-07 9:02 ` Anup Patel 2017-02-07 16:42 ` Vinod Koul 2017-02-07 16:42 ` Vinod Koul 2017-02-07 16:42 ` Vinod Koul 2017-02-08 6:37 ` Anup Patel 2017-02-08 6:37 ` Anup Patel 2017-02-08 6:37 ` Anup Patel 2017-02-07 18:16 ` Dan Williams 2017-02-07 18:16 ` Dan Williams 2017-02-07 18:16 ` Dan Williams 2017-02-08 8:57 ` Anup Patel 2017-02-08 8:57 ` Anup Patel 2017-02-08 8:57 ` Anup Patel 2017-02-08 16:24 ` Dan Williams 2017-02-08 16:24 ` Dan Williams 2017-02-08 16:24 ` Dan Williams [not found] ` <CAPcyv4iFJXxvJFrUs2jtwP9GX5NcJ8LiEDHeZ5b1fwjCAToe5w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2017-02-09 9:29 ` Anup Patel 2017-02-09 9:29 ` Anup Patel 2017-02-09 9:29 ` Anup Patel 2017-02-09 16:44 ` Dan Williams [this message] 2017-02-09 16:44 ` Dan Williams 2017-02-09 16:44 ` Dan Williams 2017-02-10 3:24 ` Anup Patel 2017-02-10 3:24 ` Anup Patel 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 ` Anup Patel 2017-02-07 8:16 ` Anup Patel 2017-02-07 8:16 ` [PATCH v2 4/5] dmaengine: Add Broadcom SBA RAID driver Anup Patel 2017-02-07 8:16 ` Anup Patel 2017-02-07 8:16 ` [PATCH v2 5/5] dt-bindings: Add DT bindings document for " Anup Patel 2017-02-07 8:16 ` Anup Patel
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