Commit 9e911414 authored by Ezequiel Garcia's avatar Ezequiel Garcia Committed by David S. Miller
Browse files

net: mv643xx_eth: Fix highmem support in non-TSO egress path 



Commit 69ad0dd7
Author: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Date:   Mon May 19 13:59:59 2014 -0300

    net: mv643xx_eth: Use dma_map_single() to map the skb fragments

caused a nasty regression by removing the support for highmem skb
fragments. By using page_address() to get the address of a fragment's
page, we are assuming a lowmem page. However, such assumption is incorrect,
as fragments can be in highmem pages, resulting in very nasty issues.

This commit fixes this by using the skb_frag_dma_map() helper,
which takes care of mapping the skb fragment properly. Additionally,
the type of mapping is now tracked, so it can be unmapped using
dma_unmap_page or dma_unmap_single when appropriate.

This commit also fixes the error path in txq_init() to release the
resources properly.

Fixes: 69ad0dd7 ("net: mv643xx_eth: Use dma_map_single() to map the skb fragments")
Reported-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: default avatarEzequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9d08da96

drivers/net/ethernet/marvell/mv643xx_eth.c

+49 −10
Original line number Diff line number Diff line
@@ -192,6 +192,10 @@ static char mv643xx_eth_driver_version[] = "1.4"; 
#define IS_TSO_HEADER(txq, addr) \

	((addr >= txq->tso_hdrs_dma) && \

	 (addr < txq->tso_hdrs_dma + txq->tx_ring_size * TSO_HEADER_SIZE))



#define DESC_DMA_MAP_SINGLE 0

#define DESC_DMA_MAP_PAGE 1



/*

 * RX/TX descriptors.

 */
@@ -362,6 +366,7 @@ struct tx_queue { 
	dma_addr_t tso_hdrs_dma;



	struct tx_desc *tx_desc_area;

	char *tx_desc_mapping; /* array to track the type of the dma mapping */

	dma_addr_t tx_desc_dma;

	int tx_desc_area_size;
@@ -750,6 +755,7 @@ txq_put_data_tso(struct net_device *dev, struct tx_queue *txq, 
	if (txq->tx_curr_desc == txq->tx_ring_size)

		txq->tx_curr_desc = 0;

	desc = &txq->tx_desc_area[tx_index];

	txq->tx_desc_mapping[tx_index] = DESC_DMA_MAP_SINGLE;



	desc->l4i_chk = 0;

	desc->byte_cnt = length;
@@ -879,14 +885,13 @@ static void txq_submit_frag_skb(struct tx_queue *txq, struct sk_buff *skb) 
		skb_frag_t *this_frag;

		int tx_index;

		struct tx_desc *desc;

		void *addr;



		this_frag = &skb_shinfo(skb)->frags[frag];

		addr = page_address(this_frag->page.p) + this_frag->page_offset;

		tx_index = txq->tx_curr_desc++;

		if (txq->tx_curr_desc == txq->tx_ring_size)

			txq->tx_curr_desc = 0;

		desc = &txq->tx_desc_area[tx_index];

		txq->tx_desc_mapping[tx_index] = DESC_DMA_MAP_PAGE;



		/*

		 * The last fragment will generate an interrupt
@@ -902,8 +907,9 @@ static void txq_submit_frag_skb(struct tx_queue *txq, struct sk_buff *skb) 


		desc->l4i_chk = 0;

		desc->byte_cnt = skb_frag_size(this_frag);

		desc->buf_ptr = dma_map_single(mp->dev->dev.parent, addr,

					       desc->byte_cnt, DMA_TO_DEVICE);

		desc->buf_ptr = skb_frag_dma_map(mp->dev->dev.parent,

						 this_frag, 0, desc->byte_cnt,

						 DMA_TO_DEVICE);

	}

}
@@ -936,6 +942,7 @@ static int txq_submit_skb(struct tx_queue *txq, struct sk_buff *skb, 
	if (txq->tx_curr_desc == txq->tx_ring_size)

		txq->tx_curr_desc = 0;

	desc = &txq->tx_desc_area[tx_index];

	txq->tx_desc_mapping[tx_index] = DESC_DMA_MAP_SINGLE;



	if (nr_frags) {

		txq_submit_frag_skb(txq, skb);
@@ -1047,9 +1054,12 @@ static int txq_reclaim(struct tx_queue *txq, int budget, int force) 
		int tx_index;

		struct tx_desc *desc;

		u32 cmd_sts;

		char desc_dma_map;



		tx_index = txq->tx_used_desc;

		desc = &txq->tx_desc_area[tx_index];

		desc_dma_map = txq->tx_desc_mapping[tx_index];



		cmd_sts = desc->cmd_sts;



		if (cmd_sts & BUFFER_OWNED_BY_DMA) {
@@ -1065,9 +1075,19 @@ static int txq_reclaim(struct tx_queue *txq, int budget, int force) 
		reclaimed++;

		txq->tx_desc_count--;



		if (!IS_TSO_HEADER(txq, desc->buf_ptr))

			dma_unmap_single(mp->dev->dev.parent, desc->buf_ptr,

					 desc->byte_cnt, DMA_TO_DEVICE);

		if (!IS_TSO_HEADER(txq, desc->buf_ptr)) {



			if (desc_dma_map == DESC_DMA_MAP_PAGE)

				dma_unmap_page(mp->dev->dev.parent,

					       desc->buf_ptr,

					       desc->byte_cnt,

					       DMA_TO_DEVICE);

			else

				dma_unmap_single(mp->dev->dev.parent,

						 desc->buf_ptr,

						 desc->byte_cnt,

						 DMA_TO_DEVICE);

		}



		if (cmd_sts & TX_ENABLE_INTERRUPT) {

			struct sk_buff *skb = __skb_dequeue(&txq->tx_skb);
@@ -1996,6 +2016,7 @@ static int txq_init(struct mv643xx_eth_private *mp, int index) 
	struct tx_queue *txq = mp->txq + index;

	struct tx_desc *tx_desc;

	int size;

	int ret;

	int i;



	txq->index = index;
@@ -2048,18 +2069,34 @@ static int txq_init(struct mv643xx_eth_private *mp, int index) 
					nexti * sizeof(struct tx_desc);

	}



	txq->tx_desc_mapping = kcalloc(txq->tx_ring_size, sizeof(char),

				       GFP_KERNEL);

	if (!txq->tx_desc_mapping) {

		ret = -ENOMEM;

		goto err_free_desc_area;

	}



	/* Allocate DMA buffers for TSO MAC/IP/TCP headers */

	txq->tso_hdrs = dma_alloc_coherent(mp->dev->dev.parent,

					   txq->tx_ring_size * TSO_HEADER_SIZE,

					   &txq->tso_hdrs_dma, GFP_KERNEL);

	if (txq->tso_hdrs == NULL) {

		dma_free_coherent(mp->dev->dev.parent, txq->tx_desc_area_size,

				  txq->tx_desc_area, txq->tx_desc_dma);

		return -ENOMEM;

		ret = -ENOMEM;

		goto err_free_desc_mapping;

	}

	skb_queue_head_init(&txq->tx_skb);



	return 0;



err_free_desc_mapping:

	kfree(txq->tx_desc_mapping);

err_free_desc_area:

	if (index == 0 && size <= mp->tx_desc_sram_size)

		iounmap(txq->tx_desc_area);

	else

		dma_free_coherent(mp->dev->dev.parent, txq->tx_desc_area_size,

				  txq->tx_desc_area, txq->tx_desc_dma);

	return ret;

}



static void txq_deinit(struct tx_queue *txq)
@@ -2077,6 +2114,8 @@ static void txq_deinit(struct tx_queue *txq) 
	else

		dma_free_coherent(mp->dev->dev.parent, txq->tx_desc_area_size,

				  txq->tx_desc_area, txq->tx_desc_dma);

	kfree(txq->tx_desc_mapping);



	if (txq->tso_hdrs)

		dma_free_coherent(mp->dev->dev.parent,

				  txq->tx_ring_size * TSO_HEADER_SIZE,

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