| Message ID | 20231031-fix-rtl8366rb-v3-1-04dfc4e7d90e@linaro.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v3] net: dsa: tag_rtl4_a: Bump min packet size | expand |
On Tue, Oct 31, 2023 at 11:45 PM Linus Walleij <linus.walleij@linaro.org> wrote: > It was reported that the "LuCI" web UI was not working properly > with a device using the RTL8366RB switch. Disabling the egress > port tagging code made the switch work again, but this is not > a good solution as we want to be able to direct traffic to a > certain port. Luiz is not seeing this on his ethernet controller so: pw-bot: cr (I've seen Vladmir do this, I don't know what it means, but seems to be how to hold back patches.) Yours, Linus Walleij
On 11/1/23 13:18, Linus Walleij wrote: > On Tue, Oct 31, 2023 at 11:45 PM Linus Walleij <linus.walleij@linaro.org> wrote: > >> It was reported that the "LuCI" web UI was not working properly >> with a device using the RTL8366RB switch. Disabling the egress >> port tagging code made the switch work again, but this is not >> a good solution as we want to be able to direct traffic to a >> certain port. > > Luiz is not seeing this on his ethernet controller so: > > pw-bot: cr > > (I've seen Vladmir do this, I don't know what it means, but seems > to be how to hold back patches.) Looking at drivers/net/ethernet/cortina/gemini.c, should not we account for when the MAC is used as a conduit and include the right amount of "MTU" bytes? Something like this (compile tested only): diff --git a/drivers/net/ethernet/cortina/gemini.c b/drivers/net/ethernet/cortina/gemini.c index 5423fe26b4ef..5143f3734c3b 100644 --- a/drivers/net/ethernet/cortina/gemini.c +++ b/drivers/net/ethernet/cortina/gemini.c @@ -36,6 +36,7 @@ #include <linux/ethtool.h> #include <linux/tcp.h> #include <linux/u64_stats_sync.h> +#include <net/dsa.h> #include <linux/in.h> #include <linux/ip.h> @@ -1151,6 +1152,13 @@ static int gmac_map_tx_bufs(struct net_device *netdev, struct sk_buff *skb, if (skb->protocol == htons(ETH_P_8021Q)) mtu += VLAN_HLEN; +#if IS_ENABLED(CONFIG_NET_DSA) + if (netdev_uses_dsa(netdev)) { + const struct dsa_device_ops *ops = skb->dev->dsa_ptr->tag_ops; + mtu += ops->needed_headroom; + } +#endif + word1 = skb->len; word3 = SOF_BIT; Also, as a separate check, might be worth annotating the various descriptor words with __le32 and appropriate le32_to_cpu() and cpu_to_le32() accessors for each of those fields.
On Thu, Nov 2, 2023 at 7:43 PM Florian Fainelli <f.fainelli@gmail.com> wrote: > Looking at drivers/net/ethernet/cortina/gemini.c, should not we account > for when the MAC is used as a conduit and include the right amount of > "MTU" bytes? Something like this (compile tested only): The DSA core already fixes this by adding the tag size to the MTU of the conduit interface, so netdev->mtu is already 1504 for this switch. I found other oddities though so I'm digging into the driver! Thanks, Linus Walleij
On 11/2/23 15:09, Linus Walleij wrote: > On Thu, Nov 2, 2023 at 7:43 PM Florian Fainelli <f.fainelli@gmail.com> wrote: > >> Looking at drivers/net/ethernet/cortina/gemini.c, should not we account >> for when the MAC is used as a conduit and include the right amount of >> "MTU" bytes? Something like this (compile tested only): > > The DSA core already fixes this by adding the tag size to the MTU > of the conduit interface, so netdev->mtu is already 1504 for this > switch. > > I found other oddities though so I'm digging into the driver! Yes indeed, I forgot about that, never mind :)
On Wed, Nov 01, 2023 at 09:18:47PM +0100, Linus Walleij wrote: > On Tue, Oct 31, 2023 at 11:45 PM Linus Walleij <linus.walleij@linaro.org> wrote: > > > It was reported that the "LuCI" web UI was not working properly > > with a device using the RTL8366RB switch. Disabling the egress > > port tagging code made the switch work again, but this is not > > a good solution as we want to be able to direct traffic to a > > certain port. > > Luiz is not seeing this on his ethernet controller so: > > pw-bot: cr > > (I've seen Vladmir do this, I don't know what it means, but seems > to be how to hold back patches.) Hi Linus, In this case it may not have activated the automation, but I do see that the patch is now marked as "Changes Requested" in patchwork, so all is well. https://patchwork.kernel.org/project/netdevbpf/list/?series=798030&state=%2A FWIIW, pw-bot is (slightly) documented here: https://docs.kernel.org/process/maintainer-netdev.html#updating-patch-status
On Sat, Nov 4, 2023 at 3:10 PM Simon Horman <horms@kernel.org> wrote: > In this case it may not have activated the automation, but > I do see that the patch is now marked as "Changes Requested" > in patchwork, so all is well. Yeah, in this case it should even be pw-bot: reject because I found the real problem elsewhere. > FWIIW, pw-bot is (slightly) documented here: > > https://docs.kernel.org/process/maintainer-netdev.html#updating-patch-status Thanks, I'm getting better at it! Yours, Linus Walleij
diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c index c327314b95e3..9c7f8a89cb82 100644 --- a/net/dsa/tag_rtl4_a.c +++ b/net/dsa/tag_rtl4_a.c @@ -41,9 +41,21 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb, u8 *tag; u16 out; - /* Pad out to at least 60 bytes */ - if (unlikely(__skb_put_padto(skb, ETH_ZLEN, false))) - return NULL; + /* Packets over 1496 bytes get dropped unless 4 bytes are added + * on the tail. 1496 is ETH_DATA_LEN - tag which is hardly + * a coinicidence, and the 4 bytes correspond to the tag length + * and this is hardly a coinicidence so we use these defines + * here. + */ + if (skb->len >= (ETH_DATA_LEN - RTL4_A_HDR_LEN)) { + if (unlikely(__skb_pad(skb, RTL4_A_HDR_LEN, false))) + return NULL; + __skb_put(skb, RTL4_A_HDR_LEN); + } else { + /* Pad out to at least 60 bytes */ + if (unlikely(__skb_put_padto(skb, ETH_ZLEN, false))) + return NULL; + } netdev_dbg(dev, "add realtek tag to package to port %d\n", dp->index);
It was reported that the "LuCI" web UI was not working properly with a device using the RTL8366RB switch. Disabling the egress port tagging code made the switch work again, but this is not a good solution as we want to be able to direct traffic to a certain port. It turns out that packets between 1496 and 1500 bytes are dropped unless 4 extra blank bytes are added to the tail. 1496 is the size of a normal data frame minus the internal DSA tag. The number is intuitive, the explanation evades me. This is not a tail tag since frames below 1496 bytes does not need the extra bytes. As we completely lack datasheet or any insight into how this switch works, this trial-and-error solution is the best we can do. FWIW this bug may very well be the reason why Realteks code drops are not using CPU tagging. The vendor routers using this switch are all hardwired to disable CPU tagging and all packets are pushed to all ports on TX. This is also the case in the old OpenWrt driver, derived from the vendor code drops. Modifying the MTU on the switch (one setting affecting all ports) has no effect. Before this patch: PING 192.168.1.1 (192.168.1.1) 1470(1498) bytes of data. ^C --- 192.168.1.1 ping statistics --- 2 packets transmitted, 0 received, 100% packet loss, time 1048ms PING 192.168.1.1 (192.168.1.1) 1472(1500) bytes of data. ^C --- 192.168.1.1 ping statistics --- 12 packets transmitted, 0 received, 100% packet loss, time 11267ms After this patch: PING 192.168.1.1 (192.168.1.1) 1470(1498) bytes of data. 1478 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.533 ms 1478 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=0.630 ms PING 192.168.1.1 (192.168.1.1) 1472(1500) bytes of data. 1480 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=0.527 ms 1480 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=0.562 ms Also LuCI starts working with the 1500 bytes frames it produces from the HTTP server. Fixes: 9eb8bc593a5e ("net: dsa: tag_rtl4_a: fix egress tags") Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- Changes in v3: - Do not pad out to 1518 bytes, just add 4 bytes to the tail consistently when the package is bigger than 1496 bytes. Use a combination of __skb_pad() and __skb_put(). This works fine. - Add tail in the first if-clause and pad to 60 bytes in the else-clause since they are mutually exclusive. - Edit comments and commit text. - Link to v2: https://lore.kernel.org/r/20231030-fix-rtl8366rb-v2-1-e66e1ef7dbd2@linaro.org Changes in v2: - Pad packages >= 1496 bytes after some further tests - Use more to-the-point description - Provide ping results in the commit message - Link to v1: https://lore.kernel.org/r/20231027-fix-rtl8366rb-v1-1-d565d905535a@linaro.org --- net/dsa/tag_rtl4_a.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) --- base-commit: d9e164e4199bc465b3540d5fe3ffc8a9a4fc6157 change-id: 20231027-fix-rtl8366rb-e752bd5901ca Best regards,