projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| 8043cbef GKH |
1 | From 8812304cf1110ae16b0778680f6022216cf4716a Mon Sep 17 00:00:00 2001 |
| 2 | From: Raimonds Cicans <ray@apollo.lv> | |
| 3 | Date: Fri, 13 Nov 2009 10:52:19 +0000 | |
| 4 | Subject: r8169: Fix receive buffer length when MTU is between 1515 and 1536 | |
| 5 | ||
| 6 | From: Raimonds Cicans <ray@apollo.lv> | |
| 7 | ||
| 8 | commit 8812304cf1110ae16b0778680f6022216cf4716a upstream. | |
| 9 | ||
| 10 | In r8169 driver MTU is used to calculate receive buffer size. | |
| 11 | Receive buffer size is used to configure hardware incoming packet filter. | |
| 12 | ||
| 13 | For jumbo frames: | |
| 14 | Receive buffer size = Max frame size = MTU + 14 (ethernet header) + 4 | |
| 15 | (vlan header) + 4 (ethernet checksum) = MTU + 22 | |
| 16 | ||
| 17 | Bug: | |
| 18 | driver for all MTU up to 1536 use receive buffer size 1536 | |
| 19 | ||
| 20 | As you can see from formula, this mean all IP packets > 1536 - 22 | |
| 21 | (for vlan tagged, 1536 - 18 for not tagged) are dropped by hardware | |
| 22 | filter. | |
| 23 | ||
| 24 | Example: | |
| 25 | ||
| 26 | host_good> ifconfig eth0 mtu 1536 | |
| 27 | host_r8169> ifconfig eth0 mtu 1536 | |
| 28 | host_good> ping host_r8169 | |
| 29 | Ok | |
| 30 | host_good> ping -s 1500 host_r8169 | |
| 31 | Fail | |
| 32 | host_good> ifconfig eth0 mtu 7000 | |
| 33 | host_r8169> ifconfig eth0 mtu 7000 | |
| 34 | host_good> ping -s 1500 host_r8169 | |
| 35 | Ok | |
| 36 | ||
| 37 | Bonus: got rid of magic number 8 | |
| 38 | ||
| 39 | Signed-off-by: Raimonds Cicans <ray@apollo.lv> | |
| 40 | Signed-off-by: David S. Miller <davem@davemloft.net> | |
| 41 | Cc: Jean Delvare <khali@linux-fr.org> | |
| 42 | Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> | |
| 43 | ||
| 44 | --- | |
| 45 | drivers/net/r8169.c | 4 ++-- | |
| 46 | 1 file changed, 2 insertions(+), 2 deletions(-) | |
| 47 | ||
| 48 | --- a/drivers/net/r8169.c | |
| 49 | +++ b/drivers/net/r8169.c | |
| 50 | @@ -1842,9 +1842,9 @@ static void __devexit rtl8169_remove_one | |
| 51 | static void rtl8169_set_rxbufsize(struct rtl8169_private *tp, | |
| 52 | struct net_device *dev) | |
| 53 | { | |
| 54 | - unsigned int mtu = dev->mtu; | |
| 55 | + unsigned int max_frame = dev->mtu + VLAN_ETH_HLEN + ETH_FCS_LEN; | |
| 56 | ||
| 57 | - tp->rx_buf_sz = (mtu > RX_BUF_SIZE) ? mtu + ETH_HLEN + 8 : RX_BUF_SIZE; | |
| 58 | + tp->rx_buf_sz = (max_frame > RX_BUF_SIZE) ? max_frame : RX_BUF_SIZE; | |
| 59 | } | |
| 60 | ||
| 61 | static int rtl8169_open(struct net_device *dev) |