From: Greg KH <gregkh@linuxfoundation.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
dri-devel@lists.freedesktop.org, linux-mm@kvack.org,
devel@driverdev.osuosl.org, linux-s390@vger.kernel.org,
linux-rdma@vger.kernel.org, David Airlie <airlied@linux.ie>,
linux-media@vger.kernel.org,
Intel Linux Wireless <linuxwifi@intel.com>,
intel-gfx@lists.freedesktop.org,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Jani Nikula <jani.nikula@linux.intel.com>,
Ian Abbott <abbotti@mev.co.uk>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Sean Paul <sean@poorly.run>,
"moderated list:ARM PORT" <linux-arm-kernel@lists.infradead.org>,
netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
linux-kernel@vger.kernel.org,
H Hartley Sweeten <hsweeten@visionengravers.com>,
iommu@lists.linux-foundation.org, Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH 12/16] staging/comedi: mark as broken
Date: Fri, 14 Jun 2019 17:30:32 +0200 [thread overview]
Message-ID: <20190614153032.GD18049@kroah.com> (raw)
In-Reply-To: <20190614144857.GA9088@lst.de>
On Fri, Jun 14, 2019 at 04:48:57PM +0200, Christoph Hellwig wrote:
> On Fri, Jun 14, 2019 at 04:02:39PM +0200, Greg KH wrote:
> > Perhaps a hint as to how we can fix this up? This is the first time
> > I've heard of the comedi code not handling dma properly.
>
> It can be fixed by:
>
> a) never calling virt_to_page (or vmalloc_to_page for that matter)
> on dma allocation
> b) never remapping dma allocation with conflicting cache modes
> (no remapping should be doable after a) anyway).
Ok, fair enough, have any pointers of drivers/core code that does this
correctly? I can put it on my todo list, but might take a week or so...
Ian, want to look into doing this sooner?
thanks,
greg k-h
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next prev parent reply other threads:[~2019-06-14 15:30 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-14 13:47 use exact allocation for dma coherent memory Christoph Hellwig
2019-06-14 13:47 ` [PATCH 01/16] media: videobuf-dma-contig: use dma_mmap_coherent Christoph Hellwig
2019-06-14 13:47 ` [PATCH 02/16] drm/ati_pcigart: stop using drm_pci_alloc Christoph Hellwig
2019-06-14 13:47 ` [PATCH 03/16] drm/i915: " Christoph Hellwig
2019-06-14 16:45 ` [Intel-gfx] " Ville Syrjälä
2019-06-14 13:47 ` [PATCH 04/16] drm: move drm_pci_{alloc,free} to drm_legacy Christoph Hellwig
2019-06-14 13:47 ` [PATCH 05/16] drm: don't mark pages returned from drm_pci_alloc reserved Christoph Hellwig
2019-06-14 13:47 ` [PATCH 06/16] drm: don't pass __GFP_COMP to dma_alloc_coherent in drm_pci_alloc Christoph Hellwig
2019-06-14 13:47 ` [PATCH 07/16] IB/hfi1: stop passing bogus gfp flags arguments to dma_alloc_coherent Christoph Hellwig
2019-06-14 13:47 ` [PATCH 08/16] IB/qib: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 09/16] cnic: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 10/16] iwlwifi: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 11/16] s390/ism: " Christoph Hellwig
2019-06-14 13:47 ` [PATCH 12/16] staging/comedi: mark as broken Christoph Hellwig
2019-06-14 14:02 ` Greg KH
2019-06-14 14:48 ` Christoph Hellwig
2019-06-14 15:30 ` Greg KH [this message]
2019-06-14 15:34 ` Christoph Hellwig
2019-06-17 13:15 ` Ian Abbott
2019-06-14 13:47 ` [PATCH 13/16] mm: rename alloc_pages_exact_nid to alloc_pages_exact_node Christoph Hellwig
2019-06-14 13:47 ` [PATCH 14/16] mm: use alloc_pages_exact_node to implement alloc_pages_exact Christoph Hellwig
2019-06-14 13:47 ` [PATCH 15/16] dma-mapping: clear __GFP_COMP in dma_alloc_attrs Christoph Hellwig
2019-06-14 13:47 ` [PATCH 16/16] dma-mapping: use exact allocation in dma_alloc_contiguous Christoph Hellwig
2019-06-14 14:15 ` David Laight
2019-06-14 14:50 ` 'Christoph Hellwig'
2019-06-14 15:01 ` David Laight
2019-06-14 15:05 ` 'Christoph Hellwig'
2019-06-14 15:05 ` Robin Murphy
2019-06-14 15:08 ` 'Christoph Hellwig'
2019-06-14 15:16 ` David Laight
2019-06-17 8:21 ` use exact allocation for dma coherent memory Dan Carpenter
2019-06-17 8:33 ` Christoph Hellwig
2019-06-19 16:29 ` Jason Gunthorpe
2019-06-20 10:51 ` Christoph Hellwig
2019-07-01 8:48 ` Christoph Hellwig
2019-07-02 9:48 ` Arend Van Spriel via iommu
2019-07-08 18:43 ` Christoph Hellwig
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