[3.13.y.z extended stable] Patch "myri10ge: check for DMA mapping errors" has been added to staging queue

Kamal Mostafa kamal at canonical.com
Fri Oct 31 20:53:18 UTC 2014


This is a note to let you know that I have just added a patch titled

    myri10ge: check for DMA mapping errors

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 5f2447e23f6403b97d7d4e9e8d2c4280529b233d Mon Sep 17 00:00:00 2001
From: Stanislaw Gruszka <sgruszka at redhat.com>
Date: Tue, 12 Aug 2014 10:35:19 +0200
Subject: myri10ge: check for DMA mapping errors

[ Upstream commit 10545937e866ccdbb7ab583031dbdcc6b14e4eb4 ]

On IOMMU systems DMA mapping can fail, we need to check for
that possibility.

Signed-off-by: Stanislaw Gruszka <sgruszka at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 88 ++++++++++++++++--------
 1 file changed, 58 insertions(+), 30 deletions(-)

diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
index 68026f7..4a474dd 100644
--- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
+++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
@@ -872,6 +872,10 @@ static int myri10ge_dma_test(struct myri10ge_priv *mgp, int test_type)
 		return -ENOMEM;
 	dmatest_bus = pci_map_page(mgp->pdev, dmatest_page, 0, PAGE_SIZE,
 				   DMA_BIDIRECTIONAL);
+	if (unlikely(pci_dma_mapping_error(mgp->pdev, dmatest_bus))) {
+		__free_page(dmatest_page);
+		return -ENOMEM;
+	}

 	/* Run a small DMA test.
 	 * The magic multipliers to the length tell the firmware
@@ -1293,6 +1297,7 @@ myri10ge_alloc_rx_pages(struct myri10ge_priv *mgp, struct myri10ge_rx_buf *rx,
 			int bytes, int watchdog)
 {
 	struct page *page;
+	dma_addr_t bus;
 	int idx;
 #if MYRI10GE_ALLOC_SIZE > 4096
 	int end_offset;
@@ -1317,11 +1322,21 @@ myri10ge_alloc_rx_pages(struct myri10ge_priv *mgp, struct myri10ge_rx_buf *rx,
 					rx->watchdog_needed = 1;
 				return;
 			}
+
+			bus = pci_map_page(mgp->pdev, page, 0,
+					   MYRI10GE_ALLOC_SIZE,
+					   PCI_DMA_FROMDEVICE);
+			if (unlikely(pci_dma_mapping_error(mgp->pdev, bus))) {
+				__free_pages(page, MYRI10GE_ALLOC_ORDER);
+				if (rx->fill_cnt - rx->cnt < 16)
+					rx->watchdog_needed = 1;
+				return;
+			}
+
 			rx->page = page;
 			rx->page_offset = 0;
-			rx->bus = pci_map_page(mgp->pdev, page, 0,
-					       MYRI10GE_ALLOC_SIZE,
-					       PCI_DMA_FROMDEVICE);
+			rx->bus = bus;
+
 		}
 		rx->info[idx].page = rx->page;
 		rx->info[idx].page_offset = rx->page_offset;
@@ -2765,6 +2780,35 @@ myri10ge_submit_req(struct myri10ge_tx_buf *tx, struct mcp_kreq_ether_send *src,
 	mb();
 }

+static void myri10ge_unmap_tx_dma(struct myri10ge_priv *mgp,
+				  struct myri10ge_tx_buf *tx, int idx)
+{
+	unsigned int len;
+	int last_idx;
+
+	/* Free any DMA resources we've alloced and clear out the skb slot */
+	last_idx = (idx + 1) & tx->mask;
+	idx = tx->req & tx->mask;
+	do {
+		len = dma_unmap_len(&tx->info[idx], len);
+		if (len) {
+			if (tx->info[idx].skb != NULL)
+				pci_unmap_single(mgp->pdev,
+						 dma_unmap_addr(&tx->info[idx],
+								bus), len,
+						 PCI_DMA_TODEVICE);
+			else
+				pci_unmap_page(mgp->pdev,
+					       dma_unmap_addr(&tx->info[idx],
+							      bus), len,
+					       PCI_DMA_TODEVICE);
+			dma_unmap_len_set(&tx->info[idx], len, 0);
+			tx->info[idx].skb = NULL;
+		}
+		idx = (idx + 1) & tx->mask;
+	} while (idx != last_idx);
+}
+
 /*
  * Transmit a packet.  We need to split the packet so that a single
  * segment does not cross myri10ge->tx_boundary, so this makes segment
@@ -2788,7 +2832,7 @@ static netdev_tx_t myri10ge_xmit(struct sk_buff *skb,
 	u32 low;
 	__be32 high_swapped;
 	unsigned int len;
-	int idx, last_idx, avail, frag_cnt, frag_idx, count, mss, max_segments;
+	int idx, avail, frag_cnt, frag_idx, count, mss, max_segments;
 	u16 pseudo_hdr_offset, cksum_offset, queue;
 	int cum_len, seglen, boundary, rdma_count;
 	u8 flags, odd_flag;
@@ -2885,9 +2929,12 @@ again:

 	/* map the skb for DMA */
 	len = skb_headlen(skb);
+	bus = pci_map_single(mgp->pdev, skb->data, len, PCI_DMA_TODEVICE);
+	if (unlikely(pci_dma_mapping_error(mgp->pdev, bus)))
+		goto drop;
+
 	idx = tx->req & tx->mask;
 	tx->info[idx].skb = skb;
-	bus = pci_map_single(mgp->pdev, skb->data, len, PCI_DMA_TODEVICE);
 	dma_unmap_addr_set(&tx->info[idx], bus, bus);
 	dma_unmap_len_set(&tx->info[idx], len, len);

@@ -2986,12 +3033,16 @@ again:
 			break;

 		/* map next fragment for DMA */
-		idx = (count + tx->req) & tx->mask;
 		frag = &skb_shinfo(skb)->frags[frag_idx];
 		frag_idx++;
 		len = skb_frag_size(frag);
 		bus = skb_frag_dma_map(&mgp->pdev->dev, frag, 0, len,
 				       DMA_TO_DEVICE);
+		if (unlikely(pci_dma_mapping_error(mgp->pdev, bus))) {
+			myri10ge_unmap_tx_dma(mgp, tx, idx);
+			goto drop;
+		}
+		idx = (count + tx->req) & tx->mask;
 		dma_unmap_addr_set(&tx->info[idx], bus, bus);
 		dma_unmap_len_set(&tx->info[idx], len, len);
 	}
@@ -3022,31 +3073,8 @@ again:
 	return NETDEV_TX_OK;

 abort_linearize:
-	/* Free any DMA resources we've alloced and clear out the skb
-	 * slot so as to not trip up assertions, and to avoid a
-	 * double-free if linearizing fails */
+	myri10ge_unmap_tx_dma(mgp, tx, idx);

-	last_idx = (idx + 1) & tx->mask;
-	idx = tx->req & tx->mask;
-	tx->info[idx].skb = NULL;
-	do {
-		len = dma_unmap_len(&tx->info[idx], len);
-		if (len) {
-			if (tx->info[idx].skb != NULL)
-				pci_unmap_single(mgp->pdev,
-						 dma_unmap_addr(&tx->info[idx],
-								bus), len,
-						 PCI_DMA_TODEVICE);
-			else
-				pci_unmap_page(mgp->pdev,
-					       dma_unmap_addr(&tx->info[idx],
-							      bus), len,
-					       PCI_DMA_TODEVICE);
-			dma_unmap_len_set(&tx->info[idx], len, 0);
-			tx->info[idx].skb = NULL;
-		}
-		idx = (idx + 1) & tx->mask;
-	} while (idx != last_idx);
 	if (skb_is_gso(skb)) {
 		netdev_err(mgp->dev, "TSO but wanted to linearize?!?!?\n");
 		goto drop;
--
1.9.1





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