netdev - Re: [PATCH 21/62] net: remove the second argument of k[un]map

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Date:	Sun, 27 Nov 2011 09:07:28 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Cong Wang <amwang@...hat.com>
Cc:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
	Jesse Brandeburg <jesse.brandeburg@...el.com>,
	Bruce Allan <bruce.w.allan@...el.com>,
	Carolyn Wyborny <carolyn.wyborny@...el.com>,
	Don Skidmore <donald.c.skidmore@...el.com>,
	Greg Rose <gregory.v.rose@...el.com>,
	Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@...el.com>,
	Alex Duyck <alexander.h.duyck@...el.com>,
	John Ronciak <john.ronciak@...el.com>,
	"David S. Miller" <davem@...emloft.net>,
	Dean Nelson <dnelson@...hat.com>,
	Ian Campbell <ian.campbell@...rix.com>,
	Jiri Pirko <jpirko@...hat.com>,
	e1000-devel@...ts.sourceforge.net, netdev@...r.kernel.org
Subject: Re: [PATCH 21/62] net: remove the second argument of
 k[un]map_atomic()

Le dimanche 27 novembre 2011 à 13:27 +0800, Cong Wang a écrit :
> Signed-off-by: Cong Wang <amwang@...hat.com>
> ---

> diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
> index cf480b5..b194beb 100644
> --- a/drivers/net/ethernet/intel/e1000/e1000_main.c
> +++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
> @@ -3878,11 +3878,9 @@ static bool e1000_clean_jumbo_rx_irq(struct e1000_adapter *adapter,
>  				if (length <= copybreak &&
>  				    skb_tailroom(skb) >= length) {
>  					u8 *vaddr;
> -					vaddr = kmap_atomic(buffer_info->page,
> -					                    KM_SKB_DATA_SOFTIRQ);
> +					vaddr = kmap_atomic(buffer_info->page);
>  					memcpy(skb_tail_pointer(skb), vaddr, length);
> -					kunmap_atomic(vaddr,
> -					              KM_SKB_DATA_SOFTIRQ);
> +					kunmap_atomic(vaddr);
>  					/* re-use the page, so don't erase
>  					 * buffer_info->page */
>  					skb_put(skb, length);
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index a855db1..8603c87 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -1272,9 +1272,9 @@ static bool e1000_clean_rx_irq_ps(struct e1000_adapter *adapter,
>  			 */
>  			dma_sync_single_for_cpu(&pdev->dev, ps_page->dma,
>  						PAGE_SIZE, DMA_FROM_DEVICE);
> -			vaddr = kmap_atomic(ps_page->page, KM_SKB_DATA_SOFTIRQ);
> +			vaddr = kmap_atomic(ps_page->page);
>  			memcpy(skb_tail_pointer(skb), vaddr, l1);
> -			kunmap_atomic(vaddr, KM_SKB_DATA_SOFTIRQ);
> +			kunmap_atomic(vaddr);
>  			dma_sync_single_for_device(&pdev->dev, ps_page->dma,
>  						   PAGE_SIZE, DMA_FROM_DEVICE);
>  
> @@ -1465,12 +1465,10 @@ static bool e1000_clean_jumbo_rx_irq(struct e1000_adapter *adapter,
>  				if (length <= copybreak &&
>  				    skb_tailroom(skb) >= length) {
>  					u8 *vaddr;
> -					vaddr = kmap_atomic(buffer_info->page,
> -					                   KM_SKB_DATA_SOFTIRQ);
> +					vaddr = kmap_atomic(buffer_info->page);
>  					memcpy(skb_tail_pointer(skb), vaddr,
>  					       length);
> -					kunmap_atomic(vaddr,
> -					              KM_SKB_DATA_SOFTIRQ);
> +					kunmap_atomic(vaddr);
>  					/* re-use the page, so don't erase
>  					 * buffer_info->page */
>  					skb_put(skb, length);

But why are these drivers using kmap_atomic() in first place, since
their fragments are allocated in regular zone (GFP_ATOMIC or
GFP_KERNEL) ?




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