From: Christoph Hellwig <hch@lst.de>
To: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org,
Christoph Hellwig <hch@lst.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH kernel v2 1/2] dma: Allow mixing bypass and normal IOMMU operation
Date: Wed, 28 Oct 2020 18:21:06 +0100 [thread overview]
Message-ID: <20201028172106.GA10015@lst.de> (raw)
In-Reply-To: <28147035-500d-f3cd-f283-257066343697@ozlabs.ru>
On Wed, Oct 28, 2020 at 05:55:23PM +1100, Alexey Kardashevskiy wrote:
>
> It is passing an address of the end of the mapped area so passing a page
> struct means passing page and offset which is an extra parameter and we do
> not want to do anything with the page in those hooks anyway so I'd keep it
> as is.
>
>
>> and
>> maybe even hide the dma_map_direct inside it.
>
> Call dma_map_direct() from arch_dma_map_page_direct() if
> arch_dma_map_page_direct() is defined? Seems suboptimal as it is going to
> be bypass=true in most cases and we save one call by avoiding calling
> arch_dma_map_page_direct(). Unless I missed something?
C does not even evaluate the right hand side of a || expression if the
left hand evaluates to true.
next prev parent reply other threads:[~2020-10-28 17:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 10:18 [PATCH kernel v2 0/2] DMA, powerpc/dma: Fallback to dma_ops when persistent memory present Alexey Kardashevskiy
2020-10-27 10:18 ` [PATCH kernel v2 1/2] dma: Allow mixing bypass and normal IOMMU operation Alexey Kardashevskiy
2020-10-27 16:48 ` Christoph Hellwig
2020-10-28 6:55 ` Alexey Kardashevskiy
2020-10-28 17:21 ` Christoph Hellwig [this message]
2020-10-28 23:11 ` Alexey Kardashevskiy
2020-10-27 10:18 ` [PATCH kernel v2 2/2] powerpc/dma: Fallback to dma_ops when persistent memory present Alexey Kardashevskiy
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