RE: [PATCH net,v2] net: mana: Switch to page pool for jumbo frames

[Long Li]

> -----Original Message-----
> From: LKML haiyangz <lkmlhyz@xxxxxxxxxxxxx> On Behalf Of Haiyang Zhang
> Sent: Tuesday, March 25, 2025 9:33 AM
> To: linux-hyperv@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx
> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; Dexuan Cui
> <decui@xxxxxxxxxxxxx>; stephen@xxxxxxxxxxxxxxxxxx; KY Srinivasan
> <kys@xxxxxxxxxxxxx>; Paul Rosswurm <paulros@xxxxxxxxxxxxx>;
> olaf@xxxxxxxxx; vkuznets <vkuznets@xxxxxxxxxx>; davem@xxxxxxxxxxxxx;
> wei.liu@xxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> pabeni@xxxxxxxxxx; leon@xxxxxxxxxx; Long Li <longli@xxxxxxxxxxxxx>;
> ssengar@xxxxxxxxxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx;
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> shradhagupta@xxxxxxxxxxxxxxxxxxx; jesse.brandeburg@xxxxxxxxx;
> andrew+netdev@xxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx
> Subject: [PATCH net,v2] net: mana: Switch to page pool for jumbo frames
> 
> Frag allocators, such as netdev_alloc_frag(), were not designed to work for
> fragsz > PAGE_SIZE.
> 
> So, switch to page pool for jumbo frames instead of using page frag allocators.
> This driver is using page pool for smaller MTUs already.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 80f6215b450e ("net: mana: Add support for jumbo frame")
> Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> ---
> v2: updated the commit msg as suggested by Jakub Kicinski.
> 
> ---
>  drivers/net/ethernet/microsoft/mana/mana_en.c | 46 ++++---------------
>  1 file changed, 9 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c
> b/drivers/net/ethernet/microsoft/mana/mana_en.c
> index 9a8171f099b6..4d41f4cca3d8 100644
> --- a/drivers/net/ethernet/microsoft/mana/mana_en.c
> +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
> @@ -661,30 +661,16 @@ int mana_pre_alloc_rxbufs(struct mana_port_context
> *mpc, int new_mtu, int num_qu
>  	mpc->rxbpre_total = 0;
> 
>  	for (i = 0; i < num_rxb; i++) {
> -		if (mpc->rxbpre_alloc_size > PAGE_SIZE) {
> -			va = netdev_alloc_frag(mpc->rxbpre_alloc_size);
> -			if (!va)
> -				goto error;
> -
> -			page = virt_to_head_page(va);
> -			/* Check if the frag falls back to single page */
> -			if (compound_order(page) <
> -			    get_order(mpc->rxbpre_alloc_size)) {
> -				put_page(page);
> -				goto error;
> -			}
> -		} else {
> -			page = dev_alloc_page();
> -			if (!page)
> -				goto error;
> +		page = dev_alloc_pages(get_order(mpc->rxbpre_alloc_size));
> +		if (!page)
> +			goto error;
> 
> -			va = page_to_virt(page);
> -		}
> +		va = page_to_virt(page);
> 
>  		da = dma_map_single(dev, va + mpc->rxbpre_headroom,
>  				    mpc->rxbpre_datasize, DMA_FROM_DEVICE);
>  		if (dma_mapping_error(dev, da)) {
> -			put_page(virt_to_head_page(va));
> +			put_page(page);

Should we use __free_pages()?