p54usb: Fix to prevent SKB memory allocation errors with 4K page size
On x86_64 architecture with 4K page size and SLUB debugging enabled, stress
testing on p54usb has resulted in skb allocation failures of O(1) and extreme
page fragmentation. Reducing rx_mtu fixes this problem by reducing the size of
all receive skb allocations to be of O(0). This change does not impact
performance in any way.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/p54/p54common.c b/drivers/net/wireless/p54/p54common.c
index 82354b9..06c6474 100644
--- a/drivers/net/wireless/p54/p54common.c
+++ b/drivers/net/wireless/p54/p54common.c
@@ -138,6 +138,7 @@
u8 *fw_version = NULL;
size_t len;
int i;
+ int maxlen;
if (priv->rx_start)
return 0;
@@ -195,6 +196,16 @@
else
priv->rx_mtu = (size_t)
0x620 - priv->tx_hdr_len;
+ maxlen = priv->tx_hdr_len + /* USB devices */
+ sizeof(struct p54_rx_data) +
+ 4 + /* rx alignment */
+ IEEE80211_MAX_FRAG_THRESHOLD;
+ if (priv->rx_mtu > maxlen && PAGE_SIZE == 4096) {
+ printk(KERN_INFO "p54: rx_mtu reduced from %d "
+ "to %d\n", priv->rx_mtu,
+ maxlen);
+ priv->rx_mtu = maxlen;
+ }
break;
}
case BR_CODE_EXPOSED_IF: