Messages in this thread | | | From | "陈华才" <> | Subject | Re: [PATCH 2/2] scsi: Align queue to ARCH_DMA_MINALIGN innon-coherent DMA mode | Date | Mon, 11 Sep 2017 16:41:51 +0800 |
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Hi, Christoph
I think we cannot modify dma_get_cache_alignment(), because existing callers may want to unconditionally return ARCH_DMA_MINALIGN.
Huacai
------------------ Original ------------------ From: "Christoph Hellwig"<hch@infradead.org>; Date: Mon, Sep 11, 2017 03:39 PM To: "Huacai Chen"<chenhc@lemote.com>; Cc: "James E . J . Bottomley"<jejb@linux.vnet.ibm.com>; "Martin K . Petersen"<martin.petersen@oracle.com>; "Fuxin Zhang"<zhangfx@lemote.com>; "linux-scsi"<linux-scsi@vger.kernel.org>; "linux-kernel"<linux-kernel@vger.kernel.org>; "stable"<stable@vger.kernel.org>; Subject: Re: [PATCH 2/2] scsi: Align queue to ARCH_DMA_MINALIGN innon-coherent DMA mode
> + if (plat_device_is_coherent(dev))
We can't just call platform device code. We'll need a proper DMA API call for this.
> + blk_queue_dma_alignment(q, 0x04 - 1); > + else > + blk_queue_dma_alignment(q, dma_get_cache_alignment() - 1);
Which we already have with dma_get_cache_alignment, except that it doesn't take a struct device pointer and doesn't call into dma_map ops. So please add a struct device argument to dma_get_cache_alignment, and let it call into dma_map_ops where needed.
With that you can replace the above with:
blk_queue_dma_alignment(q, max(0x04U, dma_get_cache_alignment(dev)) - 1); | |