From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Christoph Hellwig <hch@lst.de>
Cc: iommu@lists.linux-foundation.org,
"Linus Torvalds" <torvalds@linux-foundation.org>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Tariq Toukan" <tariqt@mellanox.com>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Toke Høiland-Jørgensen" <toke@toke.dk>,
"Robin Murphy" <robin.murphy@arm.com>,
"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
"Tony Luck" <tony.luck@intel.com>,
"Fenghua Yu" <fenghua.yu@intel.com>,
"Keith Busch" <keith.busch@intel.com>,
"Jonathan Derrick" <jonathan.derrick@intel.com>,
linux-pci@vger.kernel.org, linux-ia64@vger.kernel.org,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 15/15] dma-mapping: bypass indirect calls for dma-direct
Date: Fri, 14 Dec 2018 15:32:43 +0100 [thread overview]
Message-ID: <e509aa31-aa97-8c54-9205-cd2c086ba9fe@samsung.com> (raw)
In-Reply-To: <20181214142435.GA18448@lst.de>
Hi Christoph,
On 2018-12-14 15:24, Christoph Hellwig wrote:
> On Fri, Dec 14, 2018 at 03:11:37PM +0100, Marek Szyprowski wrote:
>> Hi Christoph,
>>
>> On 2018-12-07 20:07, Christoph Hellwig wrote:
>>> Avoid expensive indirect calls in the fast path DMA mapping
>>> operations by directly calling the dma_direct_* ops if we are using
>>> the directly mapped DMA operations.
>>>
>>> Signed-off-by: Christoph Hellwig <hch@lst.de>
>> This breaks direct DMA on ARM64 (also todays linux-next). NULL
>> dev->dma_ops fallbacks to get_arch_dma_ops(), which in turn returns
>> non-functional &dma_dummy_ops on ARM64...
> Yeah, fallback from direct (NULL) dev->dma_ops to something else won't
> work with NULL as the indicator.
>
> Fortunately we shouldn't even need that thanks to the patch from Robin
> that explicitly set the dummy ops where needed.
>
> Can you try the patch below?
Yes, it fixes the problem.
> diff --git a/arch/arm64/include/asm/dma-mapping.h b/arch/arm64/include/asm/dma-mapping.h
> index 273e778f7de2..95dbf3ef735a 100644
> --- a/arch/arm64/include/asm/dma-mapping.h
> +++ b/arch/arm64/include/asm/dma-mapping.h
> @@ -26,11 +26,7 @@
>
> static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus)
> {
> - /*
> - * We expect no ISA devices, and all other DMA masters are expected to
> - * have someone call arch_setup_dma_ops at device creation time.
> - */
> - return &dma_dummy_ops;
> + return NULL;
> }
>
> void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>
>
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2018-12-14 14:32 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-07 19:07 [RFC] avoid indirect calls for DMA direct mappings v2 Christoph Hellwig
2018-12-07 19:07 ` [PATCH 01/15] swiotlb: remove SWIOTLB_MAP_ERROR Christoph Hellwig
2018-12-07 19:07 ` [PATCH 02/15] swiotlb: remove dma_mark_clean Christoph Hellwig
2019-01-02 21:53 ` Tony Luck
2019-01-03 7:23 ` Christoph Hellwig
2019-01-03 17:35 ` Tony Luck
2019-01-04 8:09 ` Christoph Hellwig
2018-12-07 19:07 ` [PATCH 03/15] dma-direct: improve addressability error reporting Christoph Hellwig
2018-12-07 19:07 ` [PATCH 04/15] dma-direct: use dma_direct_map_page to implement dma_direct_map_sg Christoph Hellwig
2018-12-07 19:07 ` [PATCH 05/15] dma-direct: merge swiotlb_dma_ops into the dma_direct code Christoph Hellwig
2018-12-07 19:07 ` [PATCH 06/15] dma-mapping: simplify the dma_sync_single_range_for_{cpu,device} implementation Christoph Hellwig
2018-12-07 19:07 ` [PATCH 07/15] dma-mapping: merge dma_unmap_page_attrs and dma_unmap_single_attrs Christoph Hellwig
2018-12-07 19:07 ` [PATCH 08/15] dma-mapping: move dma_get_required_mask to kernel/dma Christoph Hellwig
2018-12-07 19:07 ` [PATCH 09/15] dma-mapping: move various slow path functions out of line Christoph Hellwig
2018-12-07 19:07 ` [PATCH 10/15] dma-mapping: move dma_cache_sync " Christoph Hellwig
2018-12-07 19:07 ` [PATCH 11/15] dma-mapping: always build the direct mapping code Christoph Hellwig
2018-12-07 19:07 ` [PATCH 12/15] dma-mapping: factor out dummy DMA ops Christoph Hellwig
2018-12-07 19:07 ` [PATCH 13/15] ACPI / scan: Refactor _CCA enforcement Christoph Hellwig
2018-12-14 21:15 ` Bjorn Helgaas
2018-12-07 19:07 ` [PATCH 14/15] vmd: use the proper dma_* APIs instead of direct methods calls Christoph Hellwig
2018-12-14 21:17 ` Bjorn Helgaas
2018-12-14 21:34 ` Derrick, Jonathan
2018-12-07 19:07 ` [PATCH 15/15] dma-mapping: bypass indirect calls for dma-direct Christoph Hellwig
2018-12-14 14:11 ` Marek Szyprowski
2018-12-14 14:24 ` Christoph Hellwig
2018-12-14 14:32 ` Marek Szyprowski [this message]
2018-12-15 17:46 ` [15/15] " Guenter Roeck
2018-12-16 9:02 ` Christoph Hellwig
2018-12-18 20:34 ` Guillaume Tucker
2018-12-18 20:42 ` Robin Murphy
2018-12-19 6:42 ` Christoph Hellwig
2018-12-20 16:44 ` [PATCH 15/15] " Thierry Reding
2018-12-20 16:46 ` Christoph Hellwig
2018-12-08 16:06 ` [RFC] avoid indirect calls for DMA direct mappings v2 Jesper Dangaard Brouer
2018-12-08 16:50 ` Christoph Hellwig
2018-12-10 21:51 ` Luck, Tony
2018-12-11 6:51 ` Christoph Hellwig
2018-12-11 16:42 ` Luck, Tony
2018-12-11 17:13 ` Luck, Tony
2018-12-11 17:15 ` Christoph Hellwig
2018-12-13 20:08 ` Christoph Hellwig
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