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From: Christoph Hellwig <>
	Marek Szyprowski <>
Cc: Vladimir Murzin <>,
	Takashi Iwai <>, Helge Deller <>,
	Robin Murphy <>,
	Michal Simek <>,,,,,,,,
Subject: remove default fallbacks in dma_map_ops v3
Date: Thu,  8 Aug 2019 18:59:57 +0300
Message-ID: <> (raw)

Hi all,

we have a few places where the DMA mapping layer has non-trivial default
actions that are questionable and/or dangerous.

This series instead wires up the mmap, get_sgtable and get_required_mask
methods explicitly and cleans up some surrounding areas.  This also means
we could get rid of the ARCH_NO_COHERENT_DMA_MMAP kconfig option, as we
now require a mmap method wired up, or in case of non-coherent dma-direct
the presence of the arch_dma_coherent_to_pfn hook.  The only interesting
case is that the sound code also checked the ARCH_NO_COHERENT_DMA_MMAP
symbol in somewhat odd ways, so I'd like to see a review of the sound
situation before going forward with that patch.

Changes since v2:
 - fix use of dma_can_mmap in alsa
 - improve the CONFIG_* mess a little more

Changes since v1:
 - add a dma_can_mmap helper for alsa

             reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-08 15:59 Christoph Hellwig [this message]
2019-08-08 15:59 ` [PATCH 1/8] dma-mapping: provide a better default ->get_required_mask Christoph Hellwig
2019-08-08 15:59 ` [PATCH 2/8] dma-mapping: move the dma_get_sgtable API comments from arm to common code Christoph Hellwig
2019-08-08 16:00 ` [PATCH 3/8] dma-mapping: explicitly wire up ->mmap and ->get_sgtable Christoph Hellwig
2019-08-08 16:00 ` [PATCH 4/8] dma-mapping: add a dma_can_mmap helper Christoph Hellwig
2019-08-08 16:00 ` [PATCH 5/8] ALSA: pcm: use dma_can_mmap() to check if a device supports dma_mmap_* Christoph Hellwig
2019-08-08 16:00 ` [PATCH 6/8] arm-nommu: call dma_mmap_from_dev_coherent directly Christoph Hellwig
2019-08-09  9:35   ` Sergei Shtylyov
2019-08-08 16:00 ` [PATCH 7/8] parisc: don't set ARCH_NO_COHERENT_DMA_MMAP Christoph Hellwig
2019-08-15  7:36   ` Christoph Hellwig
2019-08-15  9:25   ` James Bottomley
2019-08-15 10:50     ` Christoph Hellwig
2019-08-19 14:25       ` Christoph Hellwig
2019-08-08 16:00 ` [PATCH 8/8] dma-mapping: remove CONFIG_ARCH_NO_COHERENT_DMA_MMAP Christoph Hellwig
2019-08-09  7:21   ` Geert Uytterhoeven
2019-08-29 15:38 ` remove default fallbacks in dma_map_ops v3 Christoph Hellwig

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