Commit c1914458 authored by Anirudh Venkataramanan's avatar Anirudh Venkataramanan Committed by David S. Miller
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cassini: Use page_address() instead of kmap_atomic() 



Pages for Rx buffers are allocated in cas_page_alloc() using either
GFP_ATOMIC or GFP_KERNEL. Memory allocated with GFP_KERNEL/GFP_ATOMIC can't
come from highmem and so there's no need to kmap() them. Just use
page_address() instead. This makes the variable 'addr' unnecessary, so
remove it too.

Note that kmap_atomic() disables preemption and page-fault processing,
but page_address() doesn't. When removing uses of kmap_atomic(), one has to
check if the code being executed between the map/unmap implicitly depends
on page-faults and/or preemption being disabled. If yes, then code to
disable page-faults and/or preemption should also be added for functional
correctness. That however doesn't appear to be the case here, so just
page_address() is used.

I don't have hardware, so this change has only been compile tested.

Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: default avatarAnirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f61e6d3c

drivers/net/ethernet/sun/cassini.c

+11 −23
Original line number Diff line number Diff line
@@ -1915,7 +1915,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, 
	int off, swivel = RX_SWIVEL_OFF_VAL;

	struct cas_page *page;

	struct sk_buff *skb;

	void *addr, *crcaddr;

	void *crcaddr;

	__sum16 csum;

	char *p;
@@ -1936,7 +1936,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, 
	skb_reserve(skb, swivel);



	p = skb->data;

	addr = crcaddr = NULL;

	crcaddr = NULL;

	if (hlen) { /* always copy header pages */

		i = CAS_VAL(RX_COMP2_HDR_INDEX, words[1]);

		page = cp->rx_pages[CAS_VAL(RX_INDEX_RING, i)][CAS_VAL(RX_INDEX_NUM, i)];
@@ -1948,12 +1948,10 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, 
			i += cp->crc_size;

		dma_sync_single_for_cpu(&cp->pdev->dev, page->dma_addr + off,

					i, DMA_FROM_DEVICE);

		addr = cas_page_map(page->buffer);

		memcpy(p, addr + off, i);

		memcpy(p, page_address(page->buffer) + off, i);

		dma_sync_single_for_device(&cp->pdev->dev,

					   page->dma_addr + off, i,

					   DMA_FROM_DEVICE);

		cas_page_unmap(addr);

		RX_USED_ADD(page, 0x100);

		p += hlen;

		swivel = 0;
@@ -1984,12 +1982,11 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, 
		/* make sure we always copy a header */

		swivel = 0;

		if (p == (char *) skb->data) { /* not split */

			addr = cas_page_map(page->buffer);

			memcpy(p, addr + off, RX_COPY_MIN);

			memcpy(p, page_address(page->buffer) + off,

			       RX_COPY_MIN);

			dma_sync_single_for_device(&cp->pdev->dev,

						   page->dma_addr + off, i,

						   DMA_FROM_DEVICE);

			cas_page_unmap(addr);

			off += RX_COPY_MIN;

			swivel = RX_COPY_MIN;

			RX_USED_ADD(page, cp->mtu_stride);
@@ -2036,10 +2033,8 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, 
			RX_USED_ADD(page, hlen + cp->crc_size);

		}



		if (cp->crc_size) {

			addr = cas_page_map(page->buffer);

			crcaddr  = addr + off + hlen;

		}

		if (cp->crc_size)

			crcaddr = page_address(page->buffer) + off + hlen;



	} else {

		/* copying packet */
@@ -2061,12 +2056,10 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, 
			i += cp->crc_size;

		dma_sync_single_for_cpu(&cp->pdev->dev, page->dma_addr + off,

					i, DMA_FROM_DEVICE);

		addr = cas_page_map(page->buffer);

		memcpy(p, addr + off, i);

		memcpy(p, page_address(page->buffer) + off, i);

		dma_sync_single_for_device(&cp->pdev->dev,

					   page->dma_addr + off, i,

					   DMA_FROM_DEVICE);

		cas_page_unmap(addr);

		if (p == (char *) skb->data) /* not split */

			RX_USED_ADD(page, cp->mtu_stride);

		else
@@ -2081,20 +2074,17 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, 
						page->dma_addr,

						dlen + cp->crc_size,

						DMA_FROM_DEVICE);

			addr = cas_page_map(page->buffer);

			memcpy(p, addr, dlen + cp->crc_size);

			memcpy(p, page_address(page->buffer), dlen + cp->crc_size);

			dma_sync_single_for_device(&cp->pdev->dev,

						   page->dma_addr,

						   dlen + cp->crc_size,

						   DMA_FROM_DEVICE);

			cas_page_unmap(addr);

			RX_USED_ADD(page, dlen + cp->crc_size);

		}

end_copy_pkt:

		if (cp->crc_size) {

			addr    = NULL;

		if (cp->crc_size)

			crcaddr = skb->data + alloclen;

		}



		skb_put(skb, alloclen);

	}
@@ -2103,8 +2093,6 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc, 
		/* checksum includes FCS. strip it out. */

		csum = csum_fold(csum_partial(crcaddr, cp->crc_size,

					      csum_unfold(csum)));

		if (addr)

			cas_page_unmap(addr);

	}

	skb->protocol = eth_type_trans(skb, cp->dev);

	if (skb->protocol == htons(ETH_P_IP)) {