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Message-Id: <1421928859-17923-1-git-send-email-ezequiel.garcia@free-electrons.com>
Date: Thu, 22 Jan 2015 09:14:19 -0300
From: Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>
To: David Miller <davem@...emloft.net>,
Russell King <linux@....linux.org.uk>
Cc: <netdev@...r.kernel.org>, B38611@...escale.com,
fabio.estevam@...escale.com,
Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>
Subject: [PATCH v2] net: mv643xx_eth: Fix highmem support in non-TSO egress path
Commit 69ad0dd7af22b61d9e0e68e56b6290121618b0fb
Author: Ezequiel Garcia <ezequiel.garcia@...e-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.
Fixes: 69ad0dd7af22 ("net: mv643xx_eth: Use dma_map_single() to map the skb fragments")
Reported-by: Russell King <rmk+kernel@....linux.org.uk>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>
---
Changes from v1:
* Sending the mv643xx_eth fix for now.
* Fix DMA mapping type track, to use the correct unmap call.
drivers/net/ethernet/marvell/mv643xx_eth.c | 41 +++++++++++++++++++++++++-----
1 file changed, 34 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c
index a62fc38..e4c8461 100644
--- a/drivers/net/ethernet/marvell/mv643xx_eth.c
+++ b/drivers/net/ethernet/marvell/mv643xx_eth.c
@@ -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);
@@ -2048,6 +2068,11 @@ 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)
+ return -ENOMEM;
+
/* 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,
@@ -2077,6 +2102,8 @@ 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,
--
2.2.1
--
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