Commit a65f71fe authored by Maciej Fijalkowski's avatar Maciej Fijalkowski Committed by Jeff Kirsher
Browse files

ice: map Rx buffer pages with DMA attributes 



Provide DMA_ATTR_WEAK_ORDERING and DMA_ATTR_SKIP_CPU_SYNC attributes to
the DMA API during the mapping operations on Rx side. With this change
the non-x86 platforms will be able to sync only with what is being used
(2k buffer) instead of entire page. This should yield a slight
performance improvement.

Furthermore, DMA unmap may destroy the changes that were made to the
buffer by CPU when platform is not a x86 one. DMA_ATTR_SKIP_CPU_SYNC
attribute usage fixes this issue.

Also add a sync_single_for_device call during the Rx buffer assignment,
to make sure that the cache lines are cleared before device attempting
to write to the buffer.

Signed-off-by: default avatarMaciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: default avatarAnirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: default avatarAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
parent 712edbbb

drivers/net/ethernet/intel/ice/ice_txrx.c

+20 −4
Original line number Diff line number Diff line
@@ -282,7 +282,16 @@ void ice_clean_rx_ring(struct ice_ring *rx_ring) 
		if (!rx_buf->page)

			continue;



		dma_unmap_page(dev, rx_buf->dma, PAGE_SIZE, DMA_FROM_DEVICE);

		/* Invalidate cache lines that may have been written to by

		 * device so that we avoid corrupting memory.

		 */

		dma_sync_single_range_for_cpu(dev, rx_buf->dma,

					      rx_buf->page_offset,

					      ICE_RXBUF_2048, DMA_FROM_DEVICE);



		/* free resources associated with mapping */

		dma_unmap_page_attrs(dev, rx_buf->dma, PAGE_SIZE,

				     DMA_FROM_DEVICE, ICE_RX_DMA_ATTR);

		__page_frag_cache_drain(rx_buf->page, rx_buf->pagecnt_bias);



		rx_buf->page = NULL;
@@ -409,7 +418,8 @@ ice_alloc_mapped_page(struct ice_ring *rx_ring, struct ice_rx_buf *bi) 
	}



	/* map page for use */

	dma = dma_map_page(rx_ring->dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE);

	dma = dma_map_page_attrs(rx_ring->dev, page, 0, PAGE_SIZE,

				 DMA_FROM_DEVICE, ICE_RX_DMA_ATTR);



	/* if mapping failed free memory back to system since

	 * there isn't much point in holding memory we can't use
@@ -454,6 +464,12 @@ bool ice_alloc_rx_bufs(struct ice_ring *rx_ring, u16 cleaned_count) 
		if (!ice_alloc_mapped_page(rx_ring, bi))

			goto no_bufs;



		/* sync the buffer for use by the device */

		dma_sync_single_range_for_device(rx_ring->dev, bi->dma,

						 bi->page_offset,

						 ICE_RXBUF_2048,

						 DMA_FROM_DEVICE);



		/* Refresh the desc even if buffer_addrs didn't change

		 * because each write-back erases this info.

		 */
@@ -726,8 +742,8 @@ static void ice_put_rx_buf(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf) 
		rx_ring->rx_stats.page_reuse_count++;

	} else {

		/* we are not reusing the buffer so unmap it */

		dma_unmap_page(rx_ring->dev, rx_buf->dma, PAGE_SIZE,

			       DMA_FROM_DEVICE);

		dma_unmap_page_attrs(rx_ring->dev, rx_buf->dma, PAGE_SIZE,

				     DMA_FROM_DEVICE, ICE_RX_DMA_ATTR);

		__page_frag_cache_drain(rx_buf->page, rx_buf->pagecnt_bias);

	}

drivers/net/ethernet/intel/ice/ice_txrx.h

+3 −0
Original line number Diff line number Diff line
@@ -47,6 +47,9 @@ 
#define ICE_TX_FLAGS_VLAN_M	0xffff0000

#define ICE_TX_FLAGS_VLAN_S	16



#define ICE_RX_DMA_ATTR \

	(DMA_ATTR_SKIP_CPU_SYNC | DMA_ATTR_WEAK_ORDERING)



struct ice_tx_buf {

	struct ice_tx_desc *next_to_watch;

	struct sk_buff *skb;

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