From: Larry Finger Date: Sat, 3 Jan 2009 18:45:12 +0000 (-0600) Subject: p54usb: Fix to prevent SKB memory allocation errors with 4K page size X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=51fb80fefe736db1182551fec6528d1ef095b0ea;p=openwrt%2Fstaging%2Fblogic.git 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 Signed-off-by: John W. Linville --- diff --git a/drivers/net/wireless/p54/p54common.c b/drivers/net/wireless/p54/p54common.c index 82354b974a04..06c64744df27 100644 --- a/drivers/net/wireless/p54/p54common.c +++ b/drivers/net/wireless/p54/p54common.c @@ -138,6 +138,7 @@ int p54_parse_firmware(struct ieee80211_hw *dev, const struct firmware *fw) u8 *fw_version = NULL; size_t len; int i; + int maxlen; if (priv->rx_start) return 0; @@ -195,6 +196,16 @@ int p54_parse_firmware(struct ieee80211_hw *dev, const struct firmware *fw) 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: