Re: [PATCH v2] octeontx2-pf: Use the napi_alloc_frag() to alloc the pool buffers

[Jakub Kicinski]

On Fri,  8 May 2020 19:49:53 +0800 Kevin Hao wrote:
> diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c 
> b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> index f1d2dea90a8c..612d33207326 100644
> --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> @@ -379,40 +379,33 @@ void otx2_config_irq_coalescing(struct otx2_nic *pfvf, 
> int qidx)
>                    (pfvf->hw.cq_ecount_wait - 1));
>  }
>  
> -dma_addr_t otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool,
> -                        gfp_t gfp)
> +dma_addr_t _otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool)

If you need to respin please use double underscore as a prefix, it's
a far more common style in the kernel.

>  {
>       dma_addr_t iova;
> +     u8 *buf;
>  
> -     /* Check if request can be accommodated in previous allocated page */
> -     if (pool->page && ((pool->page_offset + pool->rbsize) <=
> -         (PAGE_SIZE << pool->rbpage_order))) {
> -             pool->pageref++;
> -             goto ret;
> -     }
> -
> -     otx2_get_page(pool);
> -
> -     /* Allocate a new page */
> -     pool->page = alloc_pages(gfp | __GFP_COMP | __GFP_NOWARN,
> -                              pool->rbpage_order);
> -     if (unlikely(!pool->page))
> +     buf = napi_alloc_frag(pool->rbsize);
> +     if (unlikely(!buf))
>               return -ENOMEM;
>  
> -     pool->page_offset = 0;
> -ret:
> -     iova = (u64)otx2_dma_map_page(pfvf, pool->page, pool->page_offset,
> -                                   pool->rbsize, DMA_FROM_DEVICE);
> -     if (!iova) {
> -             if (!pool->page_offset)
> -                     __free_pages(pool->page, pool->rbpage_order);
> -             pool->page = NULL;
> +     iova = dma_map_single_attrs(pfvf->dev, buf, pool->rbsize,
> +                                 DMA_FROM_DEVICE, DMA_ATTR_SKIP_CPU_SYNC);
> +     if (unlikely(dma_mapping_error(pfvf->dev, iova)))

Thanks for doing this, but aren't you leaking the buf on DMA mapping
error?

>               return -ENOMEM;
> -     }
> -     pool->page_offset += pool->rbsize;
> +
>       return iova;
>  }