Messages in this thread | | | Date | Tue, 12 Oct 2021 06:20:32 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH v2] scsi: ibmvscsi_tgt: Use dma_alloc_noncoherent() instead of get_zeroed_page/dma_map_single() |
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On Tue, Oct 12, 2021 at 11:21:09AM +0800, Cai Huoqing wrote: > Replacing get_zeroed_page/free_page/dma_map_single/dma_unmap_single() > with dma_alloc_noncoherent/dma_free_noncoherent() helps to reduce > code size, and simplify the code, and the hardware keep DMA coherent > itself.
It might also be worth to mention that this also avoids potential bounce buffering. Although for pseries vio devices this probably can't happen anyway.
> + vscsi->cmd_q.base_addr = dma_alloc_noncoherent(&vdev->dev, PAGE_SIZE, > + &vscsi->cmd_q.crq_token, > + DMA_BIDIRECTIONAL, GFP_KERNEL);
Please avoid the overly long line.
The same comments also apply to the other patch.
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