From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Alistair Popple <alistair@popple.id.au>, linuxppc-dev@lists.ozlabs.org
Cc: Alistair Popple <alistair@popple.id.au>,
hch@lst.de, linux-kernel@vger.kernel.org
Subject: Re: powerpc/npu-dma: Remove NPU DMA ops
Date: Thu, 8 Nov 2018 08:27:45 +1100 (AEDT) [thread overview]
Message-ID: <42qzz607sKz9sCX@ozlabs.org> (raw)
In-Reply-To: <20181030110203.27257-1-alistair@popple.id.au>
On Tue, 2018-10-30 at 11:02:03 UTC, Alistair Popple wrote:
> The NPU IOMMU is setup to mirror the parent PCIe device IOMMU
> setup. Therefore it does not make sense to call dma operations such as
> dma_map_page, etc. directly on these devices. The existing dma-ops
> simply print a warning if they are ever called, however this is
> unnecessary and the warnings are likely to go unnoticed.
>
> It is instead simpler to remove these operations and let the generic
> DMA code print warnings (eg. via a NULL pointer deref) in cases of
> buggy drivers attempting dma operations on NVLink devices.
>
> Signed-off-by: Alistair Popple <alistair@popple.id.au>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/3182215dd0b2120fb942ed88430cfb
cheers
prev parent reply other threads:[~2018-11-07 21:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-30 11:02 [PATCH] powerpc/npu-dma: Remove NPU DMA ops Alistair Popple
2018-10-30 12:58 ` Christoph Hellwig
2018-10-30 13:09 ` Benjamin Herrenschmidt
2018-10-30 13:24 ` Christoph Hellwig
2018-10-30 15:01 ` Michael Ellerman
2018-11-07 21:27 ` Michael Ellerman [this message]
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