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From: Benjamin Herrenschmidt <benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
To: Alexey Kardashevskiy
	<aik-sLpHqDYs0B2HXe+LvDLADg@public.gmane.org>,
	Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
	Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
	Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>
Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
	iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 16/33] powerpc/powernv: remove dead npu-dma code
Date: Mon, 15 Oct 2018 13:45:26 +1100	[thread overview]
Message-ID: <a99ff76069ab6559a5664382a9079b5fddfee945.camel@kernel.crashing.org> (raw)
In-Reply-To: <7709932d-efb8-2c9b-5128-99cc491c302b-sLpHqDYs0B2HXe+LvDLADg@public.gmane.org>

On Mon, 2018-10-15 at 12:34 +1100, Alexey Kardashevskiy wrote:
> On 10/10/2018 00:24, Christoph Hellwig wrote:
> > This code has been unused since it was merged and is in the way of
> > cleaning up the DMA code, thus remove it.
> > 
> > This effectively reverts commit 5d2aa710 ("powerpc/powernv: Add support
> > for Nvlink NPUs").
> 
> 
> This code is heavily used by the NVIDIA GPU driver.

Some of it is, yes. And while I don't want to be involved in the
discussion about that specific can of worms, there is code in this file
related to the custom "always error" DMA ops that I suppose we could
remove, which is what is getting in the way of Christoph cleanups. It's
just meant as a debug stuff to catch incorrect attempts at doing the
dma mappings on the wrong "side" of the GPU.

Cheers,
Ben.

WARNING: multiple messages have this Message-ID
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Alexey Kardashevskiy <aik@ozlabs.ru>,
	Christoph Hellwig <hch@lst.de>, Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org, iommu@lists.linux-foundation.org,
	linux-mm@kvack.org, linux-arch@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 16/33] powerpc/powernv: remove dead npu-dma code
Date: Mon, 15 Oct 2018 13:45:26 +1100	[thread overview]
Message-ID: <a99ff76069ab6559a5664382a9079b5fddfee945.camel@kernel.crashing.org> (raw)
Message-ID: <20181015024526.9ww3Qm7qHvgxJO4MRbRiU3FAltKQy5m-YKH7SfgmOJY@z> (raw)
In-Reply-To: <7709932d-efb8-2c9b-5128-99cc491c302b@ozlabs.ru>

On Mon, 2018-10-15 at 12:34 +1100, Alexey Kardashevskiy wrote:
> On 10/10/2018 00:24, Christoph Hellwig wrote:
> > This code has been unused since it was merged and is in the way of
> > cleaning up the DMA code, thus remove it.
> > 
> > This effectively reverts commit 5d2aa710 ("powerpc/powernv: Add support
> > for Nvlink NPUs").
> 
> 
> This code is heavily used by the NVIDIA GPU driver.

Some of it is, yes. And while I don't want to be involved in the
discussion about that specific can of worms, there is code in this file
related to the custom "always error" DMA ops that I suppose we could
remove, which is what is getting in the way of Christoph cleanups. It's
just meant as a debug stuff to catch incorrect attempts at doing the
dma mappings on the wrong "side" of the GPU.

Cheers,
Ben.

  parent reply	other threads:[~2018-10-15  2:45 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-09 13:24 use generic DMA mapping code in powerpc V3 Christoph Hellwig
2018-10-09 13:24 ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 01/33] powerpc: use mm zones more sensibly Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
     [not found]   ` <20181009132500.17643-2-hch-jcswGhMUV9g@public.gmane.org>
2018-10-15  0:47     ` Benjamin Herrenschmidt
2018-10-15  0:47       ` Benjamin Herrenschmidt
2018-10-09 13:24 ` [PATCH 03/33] powerpc/dma: remove the unused ISA_DMA_THRESHOLD export Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 04/33] powerpc/dma: remove the unused dma_iommu_ops export Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 05/33] powerpc/dma: split the two __dma_alloc_coherent implementations Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 06/33] powerpc/dma: remove the no-op dma_nommu_unmap_{page,sg} routines Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 07/33] powerpc/dma: untangle vio_dma_mapping_ops from dma_iommu_ops Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 09/33] powerpc/pseries: unwind dma_get_required_mask_pSeriesLP a bit Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 10/33] powerpc/pseries: use the generic iommu bypass code Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 11/33] powerpc/cell: move dma direct window setup out of dma_configure Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 12/33] powerpc/cell: use the generic iommu bypass code Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 14/33] powerpc/dart: " Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 15/33] powerpc/powernv: remove pnv_pci_ioda_pe_single_vendor Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 16/33] powerpc/powernv: remove dead npu-dma code Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
     [not found]   ` <20181009132500.17643-17-hch-jcswGhMUV9g@public.gmane.org>
2018-10-15  1:34     ` Alexey Kardashevskiy
2018-10-15  1:34       ` Alexey Kardashevskiy
     [not found]       ` <7709932d-efb8-2c9b-5128-99cc491c302b-sLpHqDYs0B2HXe+LvDLADg@public.gmane.org>
2018-10-15  2:45         ` Benjamin Herrenschmidt [this message]
2018-10-15  2:45           ` Benjamin Herrenschmidt
2018-10-15  5:50       ` Christoph Hellwig
2018-10-15  5:50         ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 17/33] powerpc/powernv: use the generic iommu bypass code Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
     [not found] ` <20181009132500.17643-1-hch-jcswGhMUV9g@public.gmane.org>
2018-10-09 13:24   ` [PATCH 02/33] powerpc/dma: remove the unused ARCH_HAS_DMA_MMAP_COHERENT define Christoph Hellwig
2018-10-09 13:24     ` Christoph Hellwig
2018-10-09 13:24   ` [PATCH 08/33] powerpc/dma: handle iommu bypass in dma_iommu_ops Christoph Hellwig
2018-10-09 13:24     ` Christoph Hellwig
2018-10-09 13:24   ` [PATCH 13/33] powerpc/dart: remove dead cleanup code in iommu_init_early_dart Christoph Hellwig
2018-10-09 13:24     ` Christoph Hellwig
2018-10-09 13:24   ` [PATCH 18/33] powerpc/dma: stop overriding dma_get_required_mask Christoph Hellwig
2018-10-09 13:24     ` Christoph Hellwig
2018-10-09 13:24   ` [PATCH 19/33] powerpc/pci: remove the dma_set_mask pci_controller ops methods Christoph Hellwig
2018-10-09 13:24     ` Christoph Hellwig
2018-10-09 13:24   ` [PATCH 20/33] powerpc/dma: remove the iommu fallback for coherent allocations Christoph Hellwig
2018-10-09 13:24     ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 21/33] powerpc/dma: remove get_pci_dma_ops Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 22/33] powerpc/dma: move pci_dma_dev_setup_swiotlb to fsl_pci.c Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 23/33] powerpc/dma: remove max_direct_dma_addr Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 24/33] powerpc/dma: fix an off-by-one in dma_capable Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 25/33] cxl: drop the dma_set_mask callback from vphb Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 26/33] powerpc/fsl_pci: simplify fsl_pci_dma_set_mask Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 27/33] dma-mapping, powerpc: simplify the arch dma_set_mask override Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 28/33] powerpc/dma: use phys_to_dma instead of get_dma_offset Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 29/33] powerpc/dma: remove get_dma_offset Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 30/33] powerpc/dma: remove set_dma_offset Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 31/33] powerpc/dma: remove dma_nommu_mmap_coherent Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:24 ` [PATCH 32/33] powerpc/dma: use generic direct and swiotlb ops Christoph Hellwig
2018-10-09 13:24   ` Christoph Hellwig
2018-10-09 13:25 ` [PATCH 33/33] powerpc/dma: trim the fat from <asm/dma-mapping.h> Christoph Hellwig
2018-10-09 13:25   ` Christoph Hellwig

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