[PATCH] (drivers/ethernet/atheros/atl1) test DMA mapping for error code
From: Thomas Fourier <hidden>
Date: 2025-06-12 15:11:26
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lkml
Subsystem:
atlx ethernet drivers, networking drivers, the rest · Maintainers:
Chris Snook, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
According to Shuah Khan[1], all `dma_map()` functions should be tested before using the pointer. This patch checks for errors in `dma_map()` calls and in case of failure, unmaps the previously dma_mapped regions and returns an error. [1] https://events.static.linuxfound.org/sites/events/files/slides/Shuah_Khan_dma_map_error.pdf Signed-off-by: Thomas Fourier <redacted> --- drivers/net/ethernet/atheros/atlx/atl1.c | 38 ++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/atheros/atlx/atl1.c b/drivers/net/ethernet/atheros/atlx/atl1.c
index cfdb546a09e7..99d7a37b4ddf 100644
--- a/drivers/net/ethernet/atheros/atlx/atl1.c
+++ b/drivers/net/ethernet/atheros/atlx/atl1.c@@ -1869,6 +1869,13 @@ static u16 atl1_alloc_rx_buffers(struct atl1_adapter *adapter) buffer_info->dma = dma_map_page(&pdev->dev, page, offset, adapter->rx_buffer_len, DMA_FROM_DEVICE); + if (dma_mapping_error(&pdev->dev, buffer_info->dma)) { + buffer_info->alloced = 0; + buffer_info->skb = NULL; + kfree_skb(skb); + adapter->soft_stats.rx_dropped++; + break; + } rfd_desc->buffer_addr = cpu_to_le64(buffer_info->dma); rfd_desc->buf_len = cpu_to_le16(adapter->rx_buffer_len); rfd_desc->coalese = 0;
@@ -2183,7 +2190,7 @@ static int atl1_tx_csum(struct atl1_adapter *adapter, struct sk_buff *skb, return 0; } -static void atl1_tx_map(struct atl1_adapter *adapter, struct sk_buff *skb, +static int atl1_tx_map(struct atl1_adapter *adapter, struct sk_buff *skb, struct tx_packet_desc *ptpd) { struct atl1_tpd_ring *tpd_ring = &adapter->tpd_ring;
@@ -2195,12 +2202,14 @@ static void atl1_tx_map(struct atl1_adapter *adapter, struct sk_buff *skb, unsigned int f; int retval; u16 next_to_use; + u16 first_mapped; u16 data_len; u8 hdr_len; buf_len -= skb->data_len; nr_frags = skb_shinfo(skb)->nr_frags; next_to_use = atomic_read(&tpd_ring->next_to_use); + first_mapped = next_to_use; buffer_info = &tpd_ring->buffer_info[next_to_use]; BUG_ON(buffer_info->skb); /* put skb in last TPD */
@@ -2216,6 +2225,8 @@ static void atl1_tx_map(struct atl1_adapter *adapter, struct sk_buff *skb, buffer_info->dma = dma_map_page(&adapter->pdev->dev, page, offset, hdr_len, DMA_TO_DEVICE); + if (dma_mapping_error(&adapter->pdev->dev, buffer_info->dma)) + goto dma_err; if (++next_to_use == tpd_ring->count) next_to_use = 0;
@@ -2242,6 +2253,8 @@ static void atl1_tx_map(struct atl1_adapter *adapter, struct sk_buff *skb, page, offset, buffer_info->length, DMA_TO_DEVICE); + if (dma_mapping_error(&adapter->pdev->dev, buffer_info->dma)) + goto dma_err; if (++next_to_use == tpd_ring->count) next_to_use = 0; }
@@ -2254,6 +2267,8 @@ static void atl1_tx_map(struct atl1_adapter *adapter, struct sk_buff *skb, buffer_info->dma = dma_map_page(&adapter->pdev->dev, page, offset, buf_len, DMA_TO_DEVICE); + if (dma_mapping_error(&adapter->pdev->dev, buffer_info->dma)) + goto dma_err; if (++next_to_use == tpd_ring->count) next_to_use = 0; }
@@ -2277,6 +2292,8 @@ static void atl1_tx_map(struct atl1_adapter *adapter, struct sk_buff *skb, buffer_info->dma = skb_frag_dma_map(&adapter->pdev->dev, frag, i * ATL1_MAX_TX_BUF_LEN, buffer_info->length, DMA_TO_DEVICE); + if (dma_mapping_error(&adapter->pdev->dev, buffer_info->dma)) + goto dma_err; if (++next_to_use == tpd_ring->count) next_to_use = 0;
@@ -2285,6 +2302,22 @@ static void atl1_tx_map(struct atl1_adapter *adapter, struct sk_buff *skb, /* last tpd's buffer-info */ buffer_info->skb = skb; + + return 0; + + dma_err: + while (first_mapped != next_to_use) { + buffer_info = &tpd_ring->buffer_info[first_mapped]; + dma_unmap_page(&adapter->pdev->dev, + buffer_info->dma, + buffer_info->length, + DMA_TO_DEVICE); + buffer_info->dma = NULL; + + if (++first_mapped == tdp_ring->count) + first_mapped = 0; + } + return -ENOMEM; } static void atl1_tx_queue(struct atl1_adapter *adapter, u16 count,
@@ -2419,7 +2452,8 @@ static netdev_tx_t atl1_xmit_frame(struct sk_buff *skb, } } - atl1_tx_map(adapter, skb, ptpd); + if (atl1_tx_map(adapter, skb, ptpd)) + return NETDEV_TX_BUSY; atl1_tx_queue(adapter, count, ptpd); atl1_update_mailbox(adapter); return NETDEV_TX_OK;
--
2.43.0