[PATCH] mv643xx_eth: Fix handling of small, unaligned fragments
Fix handling of small, unaligned fragments.
It also solves a potential deadlock if skb_linearize() returns -ENOMEM.
Signed-off-by: Paul Janzen <pcj@linux.sez.to>
Signed-off-by: Dale Farnsworth <dale@farnsworth.org>
mv643xx_eth.c | 54 +++++++++++++++++++++++++++++++-----------------------
1 file changed, 31 insertions(+), 23 deletions(-)
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/net/mv643xx_eth.c b/drivers/net/mv643xx_eth.c
index 4afb954..e01b03c 100644
--- a/drivers/net/mv643xx_eth.c
+++ b/drivers/net/mv643xx_eth.c
@@ -1093,6 +1093,25 @@
}
#endif
+/* Hardware can't handle unaligned fragments smaller than 9 bytes.
+ * This helper function detects that case.
+ */
+
+static inline unsigned int has_tiny_unaligned_frags(struct sk_buff *skb)
+{
+ unsigned int frag;
+ skb_frag_t *fragp;
+
+ for (frag = 0; frag < skb_shinfo(skb)->nr_frags; frag++) {
+ fragp = &skb_shinfo(skb)->frags[frag];
+ if (fragp->size <= 8 && fragp->page_offset & 0x7)
+ return 1;
+
+ }
+ return 0;
+}
+
+
/*
* mv643xx_eth_start_xmit
*
@@ -1136,12 +1155,19 @@
return 1;
}
+#ifdef MV643XX_CHECKSUM_OFFLOAD_TX
+ if (has_tiny_unaligned_frags(skb)) {
+ if ((skb_linearize(skb, GFP_ATOMIC) != 0)) {
+ stats->tx_dropped++;
+ printk(KERN_DEBUG "%s: failed to linearize tiny "
+ "unaligned fragment\n", dev->name);
+ return 1;
+ }
+ }
+
spin_lock_irqsave(&mp->lock, flags);
- /* Update packet info data structure -- DMA owned, first last */
-#ifdef MV643XX_CHECKSUM_OFFLOAD_TX
if (!skb_shinfo(skb)->nr_frags) {
-linear:
if (skb->ip_summed != CHECKSUM_HW) {
/* Errata BTS #50, IHL must be 5 if no HW checksum */
pkt_info.cmd_sts = ETH_TX_ENABLE_INTERRUPT |
@@ -1183,26 +1209,6 @@
} else {
unsigned int frag;
- /* Since hardware can't handle unaligned fragments smaller
- * than 9 bytes, if we find any, we linearize the skb
- * and start again. When I've seen it, it's always been
- * the first frag (probably near the end of the page),
- * but we check all frags to be safe.
- */
- for (frag = 0; frag < skb_shinfo(skb)->nr_frags; frag++) {
- skb_frag_t *fragp;
-
- fragp = &skb_shinfo(skb)->frags[frag];
- if (fragp->size <= 8 && fragp->page_offset & 0x7) {
- skb_linearize(skb, GFP_ATOMIC);
- printk(KERN_DEBUG "%s: unaligned tiny fragment"
- "%d of %d, fixed\n",
- dev->name, frag,
- skb_shinfo(skb)->nr_frags);
- goto linear;
- }
- }
-
/* first frag which is skb header */
pkt_info.byte_cnt = skb_headlen(skb);
pkt_info.buf_ptr = dma_map_single(NULL, skb->data,
@@ -1288,6 +1294,8 @@
}
}
#else
+ spin_lock_irqsave(&mp->lock, flags);
+
pkt_info.cmd_sts = ETH_TX_ENABLE_INTERRUPT | ETH_TX_FIRST_DESC |
ETH_TX_LAST_DESC;
pkt_info.l4i_chk = 0;