From: Konrad Rzeszutek Wilk <konrad@darnok.org>
To: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [mm PATCH v2 03/26] swiotlb: Add support for DMA_ATTR_SKIP_CPU_SYNC
Date: Sat, 5 Nov 2016 15:39:30 -0400 [thread overview]
Message-ID: <20161105193929.GA26349@localhost.localdomain> (raw)
In-Reply-To: <20161102111252.79519.21950.stgit@ahduyck-blue-test.jf.intel.com>
.. snip..
> @@ -561,6 +565,7 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
> * First, sync the memory before unmapping the entry
> */
> if (orig_addr != INVALID_PHYS_ADDR &&
> + !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
> ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
> swiotlb_bounce(orig_addr, tlb_addr, size, DMA_FROM_DEVICE);
>
> @@ -654,7 +659,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
> * GFP_DMA memory; fall back on map_single(), which
> * will grab memory from the lowest available address range.
> */
> - phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE);
> + phys_addr_t paddr = map_single(hwdev, 0, size,
> + DMA_FROM_DEVICE, 0);
> if (paddr == SWIOTLB_MAP_ERROR)
> goto err_warn;
>
> @@ -669,7 +675,8 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
>
> /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
> swiotlb_tbl_unmap_single(hwdev, paddr,
> - size, DMA_TO_DEVICE);
> + size, DMA_TO_DEVICE,
> + DMA_ATTR_SKIP_CPU_SYNC);
This I believe is redundant. That is swiotlb_tbl_unmap_single only
does an bounce if the dir is DMA_FROM_DEVICE or DMA_BIDIRECTIONAL.
I added /* optional. */
> goto err_warn;
> }
> }
> @@ -699,7 +706,7 @@ void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr,
> free_pages((unsigned long)vaddr, get_order(size));
> else
> /* DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single */
> - swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE);
> + swiotlb_tbl_unmap_single(hwdev, paddr, size, DMA_TO_DEVICE, 0);
.. but here you choose to put 0? I changed that to
DMA_ATTR_SKIP_CPU_SYNC and expanded the comment above.
Time to test the patches.
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next prev parent reply other threads:[~2016-11-05 19:39 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-02 11:12 [mm PATCH v2 00/26] Add support for DMA writable pages being writable by the network stack Alexander Duyck
2016-11-02 11:12 ` [mm PATCH v2 01/26] swiotlb: Drop unused functions swiotlb_map_sg and swiotlb_unmap_sg Alexander Duyck
2016-11-03 14:14 ` Christoph Hellwig
2016-11-03 14:29 ` Konrad Rzeszutek Wilk
2016-11-03 14:45 ` Christoph Hellwig
2016-11-03 15:02 ` Duyck, Alexander H
2016-11-02 11:12 ` [mm PATCH v2 02/26] swiotlb-xen: Enforce return of DMA_ERROR_CODE in mapping function Alexander Duyck
2016-11-02 11:13 ` [mm PATCH v2 03/26] swiotlb: Add support for DMA_ATTR_SKIP_CPU_SYNC Alexander Duyck
2016-11-05 19:39 ` Konrad Rzeszutek Wilk [this message]
2016-11-05 23:13 ` Alexander Duyck
2016-11-02 11:13 ` [mm PATCH v2 04/26] arch/arc: Add option to skip sync on DMA mapping Alexander Duyck
2016-11-02 11:13 ` [mm PATCH v2 05/26] arch/arm: Add option to skip sync on DMA map and unmap Alexander Duyck
2016-11-02 11:13 ` [mm PATCH v2 06/26] arch/avr32: Add option to skip sync on DMA map Alexander Duyck
2016-11-02 11:13 ` [mm PATCH v2 07/26] arch/blackfin: " Alexander Duyck
2016-11-02 11:13 ` [mm PATCH v2 08/26] arch/c6x: Add option to skip sync on DMA map and unmap Alexander Duyck
2016-11-02 11:14 ` [mm PATCH v2 09/26] arch/frv: Add option to skip sync on DMA map Alexander Duyck
2016-11-02 11:14 ` [mm PATCH v2 10/26] arch/hexagon: Add option to skip DMA sync as a part of mapping Alexander Duyck
2016-11-02 11:14 ` [mm PATCH v2 11/26] arch/m68k: " Alexander Duyck
2016-11-02 11:14 ` [mm PATCH v2 12/26] arch/metag: Add option to skip DMA sync as a part of map and unmap Alexander Duyck
2016-11-02 11:14 ` [mm PATCH v2 13/26] arch/microblaze: " Alexander Duyck
2016-11-02 11:14 ` [mm PATCH v2 14/26] arch/mips: " Alexander Duyck
2016-11-02 11:14 ` [mm PATCH v2 15/26] arch/nios2: " Alexander Duyck
2016-11-02 11:14 ` [mm PATCH v2 16/26] arch/openrisc: Add option to skip DMA sync as a part of mapping Alexander Duyck
2016-11-02 11:15 ` [mm PATCH v2 17/26] arch/parisc: Add option to skip DMA sync as a part of map and unmap Alexander Duyck
2016-11-02 11:15 ` [mm PATCH v2 18/26] arch/powerpc: Add option to skip DMA sync as a part of mapping Alexander Duyck
2016-11-04 3:16 ` Michael Ellerman
2016-11-02 11:15 ` [mm PATCH v2 19/26] arch/sh: " Alexander Duyck
2016-11-02 11:15 ` [mm PATCH v2 20/26] arch/sparc: Add option to skip DMA sync as a part of map and unmap Alexander Duyck
2016-11-02 11:15 ` [mm PATCH v2 21/26] arch/tile: " Alexander Duyck
2016-11-02 11:15 ` [mm PATCH v2 22/26] arch/xtensa: Add option to skip DMA sync as a part of mapping Alexander Duyck
2016-11-02 11:16 ` [mm PATCH v2 23/26] dma: Add calls for dma_map_page_attrs and dma_unmap_page_attrs Alexander Duyck
2016-11-02 11:16 ` [mm PATCH v2 24/26] mm: Add support for releasing multiple instances of a page Alexander Duyck
2016-11-02 11:16 ` [mm PATCH v2 25/26] igb: Update driver to make use of DMA_ATTR_SKIP_CPU_SYNC Alexander Duyck
2016-11-02 11:16 ` [mm PATCH v2 26/26] igb: Update code to better handle incrementing page count Alexander Duyck
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