From: Takashi Iwai <tiwai@suse.de>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-s390@vger.kernel.org, alsa-devel@alsa-project.org,
linux-media@vger.kernel.org,
Alexandra Winter <wintera@linux.ibm.com>,
Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
linux-rdma@vger.kernel.org, netdev@vger.kernel.org,
Takashi Iwai <tiwai@suse.com>,
Wenjia Zhang <wenjia@linux.ibm.com>,
iommu@lists.linux.dev, Russell King <linux@armlinux.org.uk>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
linux-arm-kernel@lists.infradead.org,
Marek Szyprowski <m.szyprowski@samsung.com>
Subject: Re: [PATCH 6/7] ALSA: memalloc: don't pass bogus GFP_ flags to dma_alloc_*
Date: Mon, 14 Nov 2022 10:04:37 +0100 [thread overview]
Message-ID: <87leod52l6.wl-tiwai@suse.de> (raw)
In-Reply-To: <20221113163535.884299-7-hch@lst.de>
On Sun, 13 Nov 2022 17:35:34 +0100,
Christoph Hellwig wrote:
>
> dma_alloc_coherent/dma_alloc_wc is an opaque allocator that only uses
> the GFP_ flags for allocation context control. Don't pass __GFP_COMP
> which makes no sense for an allocation that can't in any way be
> converted to a page pointer.
The addition of __GFP_COMP there was really old, it was Hugh's commit
f3d48f0373c1 at 2005:
[PATCH] unpaged: fix sound Bad page states
It mentions something about sparc32/64. I hope this isn't relevant
any longer (honestly I have no idea about that).
> Note that for dma_alloc_noncoherent and dma_alloc_noncontigous in
> combination with the DMA mmap helpers __GFP_COMP looks sketchy as well,
> so I would suggest to drop that as well after a careful audit.
Yeah, that's a cargo-cult copy&paste from the old idiom.
Should be killed altogether.
Thanks!
Takashi
WARNING: multiple messages have this Message-ID (diff)
From: Takashi Iwai <tiwai@suse.de>
To: Christoph Hellwig <hch@lst.de>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Alexandra Winter <wintera@linux.ibm.com>,
Wenjia Zhang <wenjia@linux.ibm.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
Russell King <linux@armlinux.org.uk>,
Robin Murphy <robin.murphy@arm.com>,
linux-arm-kernel@lists.infradead.org, linux-rdma@vger.kernel.org,
iommu@lists.linux.dev, linux-media@vger.kernel.org,
netdev@vger.kernel.org, linux-s390@vger.kernel.org,
alsa-devel@alsa-project.org
Subject: Re: [PATCH 6/7] ALSA: memalloc: don't pass bogus GFP_ flags to dma_alloc_*
Date: Mon, 14 Nov 2022 10:04:37 +0100 [thread overview]
Message-ID: <87leod52l6.wl-tiwai@suse.de> (raw)
In-Reply-To: <20221113163535.884299-7-hch@lst.de>
On Sun, 13 Nov 2022 17:35:34 +0100,
Christoph Hellwig wrote:
>
> dma_alloc_coherent/dma_alloc_wc is an opaque allocator that only uses
> the GFP_ flags for allocation context control. Don't pass __GFP_COMP
> which makes no sense for an allocation that can't in any way be
> converted to a page pointer.
The addition of __GFP_COMP there was really old, it was Hugh's commit
f3d48f0373c1 at 2005:
[PATCH] unpaged: fix sound Bad page states
It mentions something about sparc32/64. I hope this isn't relevant
any longer (honestly I have no idea about that).
> Note that for dma_alloc_noncoherent and dma_alloc_noncontigous in
> combination with the DMA mmap helpers __GFP_COMP looks sketchy as well,
> so I would suggest to drop that as well after a careful audit.
Yeah, that's a cargo-cult copy&paste from the old idiom.
Should be killed altogether.
Thanks!
Takashi
WARNING: multiple messages have this Message-ID (diff)
From: Takashi Iwai <tiwai@suse.de>
To: Christoph Hellwig <hch@lst.de>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Alexandra Winter <wintera@linux.ibm.com>,
Wenjia Zhang <wenjia@linux.ibm.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
Russell King <linux@armlinux.org.uk>,
Robin Murphy <robin.murphy@arm.com>,
linux-arm-kernel@lists.infradead.org, linux-rdma@vger.kernel.org,
iommu@lists.linux.dev, linux-media@vger.kernel.org,
netdev@vger.kernel.org, linux-s390@vger.kernel.org,
alsa-devel@alsa-project.org
Subject: Re: [PATCH 6/7] ALSA: memalloc: don't pass bogus GFP_ flags to dma_alloc_*
Date: Mon, 14 Nov 2022 10:04:37 +0100 [thread overview]
Message-ID: <87leod52l6.wl-tiwai@suse.de> (raw)
In-Reply-To: <20221113163535.884299-7-hch@lst.de>
On Sun, 13 Nov 2022 17:35:34 +0100,
Christoph Hellwig wrote:
>
> dma_alloc_coherent/dma_alloc_wc is an opaque allocator that only uses
> the GFP_ flags for allocation context control. Don't pass __GFP_COMP
> which makes no sense for an allocation that can't in any way be
> converted to a page pointer.
The addition of __GFP_COMP there was really old, it was Hugh's commit
f3d48f0373c1 at 2005:
[PATCH] unpaged: fix sound Bad page states
It mentions something about sparc32/64. I hope this isn't relevant
any longer (honestly I have no idea about that).
> Note that for dma_alloc_noncoherent and dma_alloc_noncontigous in
> combination with the DMA mmap helpers __GFP_COMP looks sketchy as well,
> so I would suggest to drop that as well after a careful audit.
Yeah, that's a cargo-cult copy&paste from the old idiom.
Should be killed altogether.
Thanks!
Takashi
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-11-14 9:05 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-13 16:35 stop drivers from passing GFP_COMP to dma_alloc_coherent Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` [PATCH 1/7] media: videobuf-dma-contig: use dma_mmap_coherent Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-24 14:10 ` Hans Verkuil
2022-11-24 14:10 ` Hans Verkuil
2022-11-24 14:10 ` Hans Verkuil
2022-11-29 14:00 ` Christoph Hellwig
2022-11-29 14:00 ` Christoph Hellwig
2022-11-29 14:00 ` Christoph Hellwig
2022-11-13 16:35 ` [PATCH 2/7] RDMA/hfi1: don't pass bogus GFP_ flags to dma_alloc_coherent Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-15 20:39 ` Jason Gunthorpe
2022-11-15 20:39 ` Jason Gunthorpe
2022-11-15 20:39 ` Jason Gunthorpe
2022-11-16 14:40 ` Dean Luick
2022-11-16 14:40 ` Dean Luick
2022-11-16 14:40 ` Dean Luick
2022-11-16 15:15 ` Robin Murphy
2022-11-16 15:15 ` Robin Murphy
2022-11-16 15:15 ` Robin Murphy
2022-11-16 15:45 ` Christoph Hellwig
2022-11-16 15:45 ` Christoph Hellwig
2022-11-16 15:45 ` Christoph Hellwig
2022-11-16 17:49 ` Dean Luick
2022-11-16 17:49 ` Dean Luick
2022-11-16 17:49 ` Dean Luick
2022-11-20 20:41 ` Dean Luick
2022-11-20 20:41 ` Dean Luick
2022-11-20 20:41 ` Dean Luick
2022-11-16 16:21 ` Dean Luick
2022-11-16 16:21 ` Dean Luick
2022-11-16 16:21 ` Dean Luick
2022-11-16 18:37 ` Robin Murphy
2022-11-16 18:37 ` Robin Murphy
2022-11-16 18:37 ` Robin Murphy
2022-11-13 16:35 ` [PATCH 3/7] RDMA/qib: " Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-15 20:40 ` Jason Gunthorpe
2022-11-15 20:40 ` Jason Gunthorpe
2022-11-15 20:40 ` Jason Gunthorpe
2022-11-13 16:35 ` [PATCH 4/7] cnic: " Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` [PATCH 5/7] s390/ism: " Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-16 12:39 ` Wenjia Zhang
2022-11-16 12:39 ` Wenjia Zhang
2022-11-16 12:39 ` Wenjia Zhang
2022-11-13 16:35 ` [PATCH 6/7] ALSA: memalloc: don't pass bogus GFP_ flags to dma_alloc_* Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-14 9:04 ` Takashi Iwai [this message]
2022-11-14 9:04 ` Takashi Iwai
2022-11-14 9:04 ` Takashi Iwai
2022-11-21 8:37 ` Christoph Hellwig
2022-11-21 8:37 ` Christoph Hellwig
2022-11-21 8:37 ` Christoph Hellwig
2022-11-13 16:35 ` [PATCH 7/7] dma-mapping: reject __GFP_COMP in dma_alloc_attrs Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-13 16:35 ` Christoph Hellwig
2022-11-14 8:11 ` Leon Romanovsky
2022-11-14 8:11 ` Leon Romanovsky
2022-11-14 8:11 ` Leon Romanovsky
2022-11-16 6:11 ` Christoph Hellwig
2022-11-16 6:11 ` Christoph Hellwig
2022-11-16 6:11 ` Christoph Hellwig
2022-11-16 7:11 ` Leon Romanovsky
2022-11-16 7:11 ` Leon Romanovsky
2022-11-16 7:11 ` Leon Romanovsky
2022-11-14 12:16 ` Marek Szyprowski
2022-11-14 12:16 ` Marek Szyprowski
2022-11-14 12:16 ` Marek Szyprowski
2022-11-21 8:39 ` stop drivers from passing GFP_COMP to dma_alloc_coherent Christoph Hellwig
2022-11-21 8:39 ` Christoph Hellwig
2022-11-21 8:39 ` Christoph Hellwig
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