Re: [PATCH] nvme-pci: 512 byte aligned dma pool segment quirk

[Keith Busch <kbusch@kernel.org>]

On Tue, Nov 12, 2024 at 07:50:00PM +0000, Bob Beckett wrote:
> @@ -2700,8 +2700,8 @@ static int nvme_setup_prp_pools(struct nvme_dev *dev)
>  		return -ENOMEM;
>  
>  	/* Optimisation for I/Os between 4k and 128k */
> -	dev->prp_small_pool = dma_pool_create("prp list 256", dev->dev,
> -						256, 256, 0);
> +	dev->prp_small_pool = dma_pool_create("prp list 256", dev->dev,256,
> +				       dev->ctrl.quirks & NVME_QUIRK_DMAPOOL_ALIGN_512 ? 512 : 256, 0);

This line is overly long and a bit difficult to read that way. I changed
it to this:

---
@@ -2693,15 +2693,20 @@ static int nvme_disable_prepare_reset(struct nvme_dev *dev, bool shutdown)

 static int nvme_setup_prp_pools(struct nvme_dev *dev)
 {
+       size_t small_align = 256;
+
        dev->prp_page_pool = dma_pool_create("prp list page", dev->dev,
                                                NVME_CTRL_PAGE_SIZE,
                                                NVME_CTRL_PAGE_SIZE, 0);
        if (!dev->prp_page_pool)
                return -ENOMEM;

+       if (dev->ctrl.quirks & NVME_QUIRK_DMAPOOL_ALIGN_512)
+               small_align = 512;
+
        /* Optimisation for I/Os between 4k and 128k */
        dev->prp_small_pool = dma_pool_create("prp list 256", dev->dev,
-                                               256, 256, 0);
+                                               256, small_align, 0);
        if (!dev->prp_small_pool) {
                dma_pool_destroy(dev->prp_page_pool);
                return -ENOMEM;
--