diff options
author | Thomas Petazzoni <thomas.petazzoni@free-electrons.com> | 2016-12-21 11:28:49 +0100 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2016-12-21 13:38:21 -0500 |
commit | 8354491c9d5b06709384cea91d13019bf5e61449 (patch) | |
tree | 588b9a14e5f3baaadc6e871cd283cc4371f7caf2 /drivers/net/ethernet/marvell | |
parent | f217bfde24077b6684e625dd618e3a522e6f272a (diff) |
net: mvpp2: fix dma unmapping of TX buffers for fragments
Since commit 71ce391dfb784 ("net: mvpp2: enable proper per-CPU TX
buffers unmapping"), we are not correctly DMA unmapping TX buffers for
fragments.
Indeed, the mvpp2_txq_inc_put() function only stores in the
txq_cpu->tx_buffs[] array the physical address of the buffer to be
DMA-unmapped when skb != NULL. In addition, when DMA-unmapping, we use
skb_headlen(skb) to get the size to be unmapped. Both of this works fine
for TX descriptors that are associated directly to a SKB, but not the
ones that are used for fragments, with a NULL pointer as skb:
- We have a NULL physical address when calling DMA unmap
- skb_headlen(skb) crashes because skb is NULL
This causes random crashes when fragments are used.
To solve this problem, we need to:
- Store the physical address of the buffer to be unmapped
unconditionally, regardless of whether it is tied to a SKB or not.
- Store the length of the buffer to be unmapped, which requires a new
field.
Instead of adding a third array to store the length of the buffer to be
unmapped, and as suggested by David Miller, this commit refactors the
tx_buffs[] and tx_skb[] arrays of 'struct mvpp2_txq_pcpu' into a
separate structure 'mvpp2_txq_pcpu_buf', to which a 'size' field is
added. Therefore, instead of having three arrays to allocate/free, we
have a single one, which also improve data locality, reducing the
impact on the CPU cache.
Fixes: 71ce391dfb784 ("net: mvpp2: enable proper per-CPU TX buffers unmapping")
Reported-by: Raphael G <raphael.glon@corp.ovh.com>
Cc: Raphael G <raphael.glon@corp.ovh.com>
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/marvell')
-rw-r--r-- | drivers/net/ethernet/marvell/mvpp2.c | 59 |
1 files changed, 30 insertions, 29 deletions
diff --git a/drivers/net/ethernet/marvell/mvpp2.c b/drivers/net/ethernet/marvell/mvpp2.c index dabc5418efcc..cda04b3126bc 100644 --- a/drivers/net/ethernet/marvell/mvpp2.c +++ b/drivers/net/ethernet/marvell/mvpp2.c @@ -770,6 +770,17 @@ struct mvpp2_rx_desc { u32 reserved8; }; +struct mvpp2_txq_pcpu_buf { + /* Transmitted SKB */ + struct sk_buff *skb; + + /* Physical address of transmitted buffer */ + dma_addr_t phys; + + /* Size transmitted */ + size_t size; +}; + /* Per-CPU Tx queue control */ struct mvpp2_txq_pcpu { int cpu; @@ -785,11 +796,8 @@ struct mvpp2_txq_pcpu { /* Number of Tx DMA descriptors reserved for each CPU */ int reserved_num; - /* Array of transmitted skb */ - struct sk_buff **tx_skb; - - /* Array of transmitted buffers' physical addresses */ - dma_addr_t *tx_buffs; + /* Infos about transmitted buffers */ + struct mvpp2_txq_pcpu_buf *buffs; /* Index of last TX DMA descriptor that was inserted */ int txq_put_index; @@ -979,10 +987,11 @@ static void mvpp2_txq_inc_put(struct mvpp2_txq_pcpu *txq_pcpu, struct sk_buff *skb, struct mvpp2_tx_desc *tx_desc) { - txq_pcpu->tx_skb[txq_pcpu->txq_put_index] = skb; - if (skb) - txq_pcpu->tx_buffs[txq_pcpu->txq_put_index] = - tx_desc->buf_phys_addr; + struct mvpp2_txq_pcpu_buf *tx_buf = + txq_pcpu->buffs + txq_pcpu->txq_put_index; + tx_buf->skb = skb; + tx_buf->size = tx_desc->data_size; + tx_buf->phys = tx_desc->buf_phys_addr; txq_pcpu->txq_put_index++; if (txq_pcpu->txq_put_index == txq_pcpu->size) txq_pcpu->txq_put_index = 0; @@ -4401,17 +4410,16 @@ static void mvpp2_txq_bufs_free(struct mvpp2_port *port, int i; for (i = 0; i < num; i++) { - dma_addr_t buf_phys_addr = - txq_pcpu->tx_buffs[txq_pcpu->txq_get_index]; - struct sk_buff *skb = txq_pcpu->tx_skb[txq_pcpu->txq_get_index]; + struct mvpp2_txq_pcpu_buf *tx_buf = + txq_pcpu->buffs + txq_pcpu->txq_get_index; mvpp2_txq_inc_get(txq_pcpu); - dma_unmap_single(port->dev->dev.parent, buf_phys_addr, - skb_headlen(skb), DMA_TO_DEVICE); - if (!skb) + dma_unmap_single(port->dev->dev.parent, tx_buf->phys, + tx_buf->size, DMA_TO_DEVICE); + if (!tx_buf->skb) continue; - dev_kfree_skb_any(skb); + dev_kfree_skb_any(tx_buf->skb); } } @@ -4651,15 +4659,10 @@ static int mvpp2_txq_init(struct mvpp2_port *port, for_each_present_cpu(cpu) { txq_pcpu = per_cpu_ptr(txq->pcpu, cpu); txq_pcpu->size = txq->size; - txq_pcpu->tx_skb = kmalloc(txq_pcpu->size * - sizeof(*txq_pcpu->tx_skb), - GFP_KERNEL); - if (!txq_pcpu->tx_skb) - goto error; - - txq_pcpu->tx_buffs = kmalloc(txq_pcpu->size * - sizeof(dma_addr_t), GFP_KERNEL); - if (!txq_pcpu->tx_buffs) + txq_pcpu->buffs = kmalloc(txq_pcpu->size * + sizeof(struct mvpp2_txq_pcpu_buf), + GFP_KERNEL); + if (!txq_pcpu->buffs) goto error; txq_pcpu->count = 0; @@ -4673,8 +4676,7 @@ static int mvpp2_txq_init(struct mvpp2_port *port, error: for_each_present_cpu(cpu) { txq_pcpu = per_cpu_ptr(txq->pcpu, cpu); - kfree(txq_pcpu->tx_skb); - kfree(txq_pcpu->tx_buffs); + kfree(txq_pcpu->buffs); } dma_free_coherent(port->dev->dev.parent, @@ -4693,8 +4695,7 @@ static void mvpp2_txq_deinit(struct mvpp2_port *port, for_each_present_cpu(cpu) { txq_pcpu = per_cpu_ptr(txq->pcpu, cpu); - kfree(txq_pcpu->tx_skb); - kfree(txq_pcpu->tx_buffs); + kfree(txq_pcpu->buffs); } if (txq->descs) |