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Commit e50287be authored by Sathya Perla's avatar Sathya Perla Committed by David S. Miller
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be2net: dma_sync each RX frag before passing it to the stack 



The driver currently maps a page for DMA, divides the page into multiple
frags and posts them to the HW. It un-maps the page after data is received
on all the frags of the page. This scheme doesn't work when bounce buffers
are used for DMA (swiotlb=force kernel param).

This patch fixes this problem by calling dma_sync_single_for_cpu() for each
frag (excepting the last one) so that the data is copied from the bounce
buffers. The page is un-mapped only when DMA finishes on the last frag of
the page.
(Thanks Ben H. for suggesting the dma_sync API!)

This patch also renames the "last_page_user" field of be_rx_page_info{}
struct to "last_frag" to improve readability of the fixed code.

Reported-by: default avatarLi Fengmao <li.fengmao@zte.com.cn>
Signed-off-by: default avatarSathya Perla <sathya.perla@emulex.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9e82e7f4

drivers/net/ethernet/emulex/benet/be.h

+2 −1
Original line number Original line Diff line number Diff line
@@ -261,9 +261,10 @@ struct be_tx_obj { 
/* Struct to remember the pages posted for rx frags */

/* Struct to remember the pages posted for rx frags */

struct be_rx_page_info {

struct be_rx_page_info {

	struct page *page;

	struct page *page;

	/* set to page-addr for last frag of the page & frag-addr otherwise */

	DEFINE_DMA_UNMAP_ADDR(bus);

	DEFINE_DMA_UNMAP_ADDR(bus);

	u16 page_offset;

	u16 page_offset;

	bool last_page_user;

	bool last_frag;		/* last frag of the page */

};

};





struct be_rx_stats {

struct be_rx_stats {

drivers/net/ethernet/emulex/benet/be_main.c

+22 −10
Original line number Original line Diff line number Diff line
@@ -1448,11 +1448,15 @@ static struct be_rx_page_info *get_rx_page_info(struct be_rx_obj *rxo) 
	rx_page_info = &rxo->page_info_tbl[frag_idx];

	rx_page_info = &rxo->page_info_tbl[frag_idx];

	BUG_ON(!rx_page_info->page);

	BUG_ON(!rx_page_info->page);





	if (rx_page_info->last_page_user) {

	if (rx_page_info->last_frag) {

		dma_unmap_page(&adapter->pdev->dev,

		dma_unmap_page(&adapter->pdev->dev,

			       dma_unmap_addr(rx_page_info, bus),

			       dma_unmap_addr(rx_page_info, bus),

			       adapter->big_page_size, DMA_FROM_DEVICE);

			       adapter->big_page_size, DMA_FROM_DEVICE);

		rx_page_info->last_page_user = false;

		rx_page_info->last_frag = false;

	} else {

		dma_sync_single_for_cpu(&adapter->pdev->dev,

					dma_unmap_addr(rx_page_info, bus),

					rx_frag_size, DMA_FROM_DEVICE);

	}

	}





	queue_tail_inc(rxq);

	queue_tail_inc(rxq);
@@ -1786,17 +1790,16 @@ static void be_post_rx_frags(struct be_rx_obj *rxo, gfp_t gfp) 
				rx_stats(rxo)->rx_post_fail++;

				rx_stats(rxo)->rx_post_fail++;

				break;

				break;

			}

			}

			page_info->page_offset = 0;

			page_offset = 0;

		} else {

		} else {

			get_page(pagep);

			get_page(pagep);

			page_info->page_offset = page_offset + rx_frag_size;

			page_offset += rx_frag_size;

		}

		}

		page_offset = page_info->page_offset;

		page_info->page_offset = page_offset;

		page_info->page = pagep;

		page_info->page = pagep;

		dma_unmap_addr_set(page_info, bus, page_dmaaddr);

		frag_dmaaddr = page_dmaaddr + page_info->page_offset;





		rxd = queue_head_node(rxq);

		rxd = queue_head_node(rxq);

		frag_dmaaddr = page_dmaaddr + page_info->page_offset;

		rxd->fragpa_lo = cpu_to_le32(frag_dmaaddr & 0xFFFFFFFF);

		rxd->fragpa_lo = cpu_to_le32(frag_dmaaddr & 0xFFFFFFFF);

		rxd->fragpa_hi = cpu_to_le32(upper_32_bits(frag_dmaaddr));

		rxd->fragpa_hi = cpu_to_le32(upper_32_bits(frag_dmaaddr));
@@ -1804,15 +1807,24 @@ static void be_post_rx_frags(struct be_rx_obj *rxo, gfp_t gfp) 
		if ((page_offset + rx_frag_size + rx_frag_size) >

		if ((page_offset + rx_frag_size + rx_frag_size) >

					adapter->big_page_size) {

					adapter->big_page_size) {

			pagep = NULL;

			pagep = NULL;

			page_info->last_page_user = true;

			page_info->last_frag = true;

			dma_unmap_addr_set(page_info, bus, page_dmaaddr);

		} else {

			dma_unmap_addr_set(page_info, bus, frag_dmaaddr);

		}

		}





		prev_page_info = page_info;

		prev_page_info = page_info;

		queue_head_inc(rxq);

		queue_head_inc(rxq);

		page_info = &rxo->page_info_tbl[rxq->head];

		page_info = &rxo->page_info_tbl[rxq->head];

	}

	}

	if (pagep)



		prev_page_info->last_page_user = true;

	/* Mark the last frag of a page when we break out of the above loop

	 * with no more slots available in the RXQ

	 */

	if (pagep) {

		prev_page_info->last_frag = true;

		dma_unmap_addr_set(prev_page_info, bus, page_dmaaddr);

	}





	if (posted) {

	if (posted) {

		atomic_add(posted, &rxq->used);

		atomic_add(posted, &rxq->used);