kernel/linux.git/drivers/net/dsa/ocelot, branch v5.16

net: dsa: felix: Fix memory leak in felix_setup_mmio_filtering

2021-12-09T16:09:28+00:00

Avoid a memory leak if there is not a CPU port defined. Fixes: 8d5f7954b7c8 ("net: dsa: felix: break at first CPU port during init and teardown") Addresses-Coverity-ID: 1492897 ("Resource leak") Addresses-Coverity-ID: 1492899 ("Resource leak") Signed-off-by: José Expósito Reviewed-by: Vladimir Oltean Link: https://lore.kernel.org/r/20211209110538.11585-1-jose.exposito89@gmail.com Signed-off-by: Jakub Kicinski

net: dsa: felix: fix broken VLAN-tagged PTP under VLAN-aware bridge

2021-11-03T14:22:00+00:00

Normally it is expected that the dsa_device_ops :: rcv() method finishes parsing the DSA tag and consumes it, then never looks at it again. But commit c0bcf537667c ("net: dsa: ocelot: add hardware timestamping support for Felix") added support for RX timestamping in a very unconventional way. On this switch, a partial timestamp is available in the DSA header, but the driver got away with not parsing that timestamp right away, but instead delayed that parsing for a little longer: dsa_switch_rcv(): nskb = cpu_dp->rcv(skb, dev); <------------- not here -> ocelot_rcv() ... skb = nskb; skb_push(skb, ETH_HLEN); skb->pkt_type = PACKET_HOST; skb->protocol = eth_type_trans(skb, skb->dev); ... if (dsa_skb_defer_rx_timestamp(p, skb)) <--- but here -> felix_rxtstamp() return 0; When in felix_rxtstamp(), this driver accounted for the fact that eth_type_trans() happened in the meanwhile, so it got a hold of the extraction header again by subtracting (ETH_HLEN + OCELOT_TAG_LEN) bytes from the current skb->data. This worked for quite some time but was quite fragile from the very beginning. Not to mention that having DSA tag parsing split in two different files, under different folders (net/dsa/tag_ocelot.c vs drivers/net/dsa/ocelot/felix.c) made it quite non-obvious for patches to come that they might break this. Finally, the blamed commit does the following: at the end of ocelot_rcv(), it checks whether the skb payload contains a VLAN header. If it does, and this port is under a VLAN-aware bridge, that VLAN ID might not be correct in the sense that the packet might have suffered VLAN rewriting due to TCAM rules (VCAP IS1). So we consume the VLAN ID from the skb payload using __skb_vlan_pop(), and take the classified VLAN ID from the DSA tag, and construct a hwaccel VLAN tag with the classified VLAN, and the skb payload is VLAN-untagged. The big problem is that __skb_vlan_pop() does: memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN); __skb_pull(skb, VLAN_HLEN); aka it moves the Ethernet header 4 bytes to the right, and pulls 4 bytes from the skb headroom (effectively also moving skb->data, by definition). So for felix_rxtstamp()'s fragile logic, all bets are off now. Instead of having the "extraction" pointer point to the DSA header, it actually points to 4 bytes _inside_ the extraction header. Corollary, the last 4 bytes of the "extraction" header are in fact 4 stale bytes of the destination MAC address from the Ethernet header, from prior to the __skb_vlan_pop() movement. So of course, RX timestamps are completely bogus when the system is configured in this way. The fix is actually very simple: just don't structure the code like that. For better or worse, the DSA PTP timestamping API does not offer a straightforward way for drivers to present their RX timestamps, but other drivers (sja1105) have established a simple mechanism to carry their RX timestamp from dsa_device_ops :: rcv() all the way to dsa_switch_ops :: port_rxtstamp() and even later. That mechanism is to simply save the partial timestamp to the skb->cb, and complete it later. Question: why don't we simply populate the skb's struct skb_shared_hwtstamps from ocelot_rcv(), and bother with this complication of propagating the timestamp to felix_rxtstamp()? Answer: dsa_switch_ops :: port_rxtstamp() answers the question whether PTP packets need sleepable context to retrieve the full RX timestamp. Currently felix_rxtstamp() answers "no, thanks" to that question, and calls ocelot_ptp_gettime64() from softirq atomic context. This is understandable, since Felix VSC9959 is a PCIe memory-mapped switch, so hardware access does not require sleeping. But the felix driver is preparing for the introduction of other switches where hardware access is over a slow bus like SPI or MDIO: https://lore.kernel.org/lkml/20210814025003.2449143-1-colin.foster@in-advantage.com/ So I would like to keep this code structure, so the rework needed when that driver will need PTP support will be minimal (answer "yes, I need deferred context for this skb's RX timestamp", then the partial timestamp will still be found in the skb->cb. Fixes: ea440cd2d9b2 ("net: dsa: tag_ocelot: use VLAN information from tagging header when available") Reported-by: Po Liu Cc: Yangbo Lu Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller

net: convert users of bitmap_foo() to linkmode_foo()

2021-10-24T12:58:52+00:00

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-10-14T23:50:14+00:00

tools/testing/selftests/net/ioam6.sh 7b1700e009cc ("selftests: net: modify IOAM tests for undef bits") bf77b1400a56 ("selftests: net: Test for the IOAM encapsulation with IPv6") Signed-off-by: Jakub Kicinski

net: dsa: felix: break at first CPU port during init and teardown

2021-10-13T00:35:19+00:00

The NXP LS1028A switch has two Ethernet ports towards the CPU, but only one of them is capable of acting as an NPI port at a time (inject and extract packets using DSA tags). However, using the alternative ocelot-8021q tagging protocol, it should be possible to use both CPU ports symmetrically, but for that we need to mark both ports in the device tree as DSA masters. In the process of doing that, it can be seen that traffic to/from the network stack gets broken, and this is because the Felix driver iterates through all DSA CPU ports and configures them as NPI ports. But since there can only be a single NPI port, we effectively end up in a situation where DSA thinks the default CPU port is the first one, but the hardware port configured to be an NPI is the last one. I would like to treat this as a bug, because if the updated device trees are going to start circulating, it would be really good for existing kernels to support them, too. Fixes: adb3dccf090b ("net: dsa: felix: convert to the new .change_tag_protocol DSA API") Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: Jakub Kicinski

net: dsa: felix: purge skb from TX timestamping queue if it cannot be sent

2021-10-13T00:35:18+00:00

At present, when a PTP packet which requires TX timestamping gets dropped under congestion by the switch, things go downhill very fast. The driver keeps a clone of that skb in a queue of packets awaiting TX timestamp interrupts, but interrupts will never be raised for the dropped packets. Moreover, matching timestamped packets to timestamps is done by a 2-bit timestamp ID, and this can wrap around and we can match on the wrong skb. Since with the default NPI-based tagging protocol, we get no notification about packet drops, the best we can do is eventually recover from the drop of a PTP frame: its skb will be dead memory until another skb which was assigned the same timestamp ID happens to find it. However, with the ocelot-8021q tagger which injects packets using the manual register interface, it appears that we can check for more information, such as: - whether the input queue has reached the high watermark or not - whether the injection group's FIFO can accept additional data or not so we know that a PTP frame is likely to get dropped before actually sending it, and drop it ourselves (because DSA uses NETIF_F_LLTX, so it can't return NETDEV_TX_BUSY to ask the qdisc to requeue the packet). But when we do that, we can also remove the skb from the timestamping queue, because there surely won't be any timestamp that matches it. Fixes: 0a6f17c6ae21 ("net: dsa: tag_ocelot_8021q: add support for PTP timestamping") Signed-off-by: Vladimir Oltean Signed-off-by: Jakub Kicinski

net: dsa: tag_ocelot_8021q: break circular dependency with ocelot switch lib

2021-10-13T00:35:18+00:00

Michael reported that when using the "ocelot-8021q" tagging protocol, the switch driver module must be manually loaded before the tagging protocol can be loaded/is available. This appears to be the same problem described here: https://lore.kernel.org/netdev/20210908220834.d7gmtnwrorhharna@skbuf/ where due to the fact that DSA tagging protocols make use of symbols exported by the switch drivers, circular dependencies appear and this breaks module autoloading. The ocelot_8021q driver needs the ocelot_can_inject() and ocelot_port_inject_frame() functions from the switch library. Previously the wrong approach was taken to solve that dependency: shims were provided for the case where the ocelot switch library was compiled out, but that turns out to be insufficient, because the dependency when the switch lib _is_ compiled is problematic too. We cannot declare ocelot_can_inject() and ocelot_port_inject_frame() as static inline functions, because these access I/O functions like __ocelot_write_ix() which is called by ocelot_write_rix(). Making those static inline basically means exposing the whole guts of the ocelot switch library, not ideal... We already have one tagging protocol driver which calls into the switch driver during xmit but not using any exported symbol: sja1105_defer_xmit. We can do the same thing here: create a kthread worker and one work item per skb, and let the switch driver itself do the register accesses to send the skb, and then consume it. Fixes: 0a6f17c6ae21 ("net: dsa: tag_ocelot_8021q: add support for PTP timestamping") Reported-by: Michael Walle Signed-off-by: Vladimir Oltean Signed-off-by: Jakub Kicinski

net: mscc: ocelot: avoid overflowing the PTP timestamp FIFO

2021-10-13T00:35:17+00:00

PTP packets with 2-step TX timestamp requests are matched to packets based on the egress port number and a 6-bit timestamp identifier. All PTP timestamps are held in a common FIFO that is 128 entry deep. This patch ensures that back-to-back timestamping requests cannot exceed the hardware FIFO capacity. If that happens, simply send the packets without requesting a TX timestamp to be taken (in the case of felix, since the DSA API has a void return code in ds->ops->port_txtstamp) or drop them (in the case of ocelot). I've moved the ts_id_lock from a per-port basis to a per-switch basis, because we need separate accounting for both numbers of PTP frames in flight. And since we need locking to inc/dec the per-switch counter, that also offers protection for the per-port counter and hence there is no reason to have a per-port counter anymore. Fixes: 4e3b0468e6d7 ("net: mscc: PTP Hardware Clock (PHC) support") Signed-off-by: Vladimir Oltean Signed-off-by: Jakub Kicinski

net: dsa: felix: accept "ethernet-ports" OF node name

2021-09-24T13:07:59+00:00

Since both forms are accepted, let's search for both when we pre-validate the PHY modes. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: be compatible with masters which unregister on shutdown

2021-09-19T11:08:37+00:00

Lino reports that on his system with bcmgenet as DSA master and KSZ9897 as a switch, rebooting or shutting down never works properly. What does the bcmgenet driver have special to trigger this, that other DSA masters do not? It has an implementation of ->shutdown which simply calls its ->remove implementation. Otherwise said, it unregisters its network interface on shutdown. This message can be seen in a loop, and it hangs the reboot process there: unregister_netdevice: waiting for eth0 to become free. Usage count = 3 So why 3? A usage count of 1 is normal for a registered network interface, and any virtual interface which links itself as an upper of that will increment it via dev_hold. In the case of DSA, this is the call path: dsa_slave_create -> netdev_upper_dev_link -> __netdev_upper_dev_link -> __netdev_adjacent_dev_insert -> dev_hold So a DSA switch with 3 interfaces will result in a usage count elevated by two, and netdev_wait_allrefs will wait until they have gone away. Other stacked interfaces, like VLAN, watch NETDEV_UNREGISTER events and delete themselves, but DSA cannot just vanish and go poof, at most it can unbind itself from the switch devices, but that must happen strictly earlier compared to when the DSA master unregisters its net_device, so reacting on the NETDEV_UNREGISTER event is way too late. It seems that it is a pretty established pattern to have a driver's ->shutdown hook redirect to its ->remove hook, so the same code is executed regardless of whether the driver is unbound from the device, or the system is just shutting down. As Florian puts it, it is quite a big hammer for bcmgenet to unregister its net_device during shutdown, but having a common code path with the driver unbind helps ensure it is well tested. So DSA, for better or for worse, has to live with that and engage in an arms race of implementing the ->shutdown hook too, from all individual drivers, and do something sane when paired with masters that unregister their net_device there. The only sane thing to do, of course, is to unlink from the master. However, complications arise really quickly. The pattern of redirecting ->shutdown to ->remove is not unique to bcmgenet or even to net_device drivers. In fact, SPI controllers do it too (see dspi_shutdown -> dspi_remove), and presumably, I2C controllers and MDIO controllers do it too (this is something I have not researched too deeply, but even if this is not the case today, it is certainly plausible to happen in the future, and must be taken into consideration). Since DSA switches might be SPI devices, I2C devices, MDIO devices, the insane implication is that for the exact same DSA switch device, we might have both ->shutdown and ->remove getting called. So we need to do something with that insane environment. The pattern I've come up with is "if this, then not that", so if either ->shutdown or ->remove gets called, we set the device's drvdata to NULL, and in the other hook, we check whether the drvdata is NULL and just do nothing. This is probably not necessary for platform devices, just for devices on buses, but I would really insist for consistency among drivers, because when code is copy-pasted, it is not always copy-pasted from the best sources. So depending on whether the DSA switch's ->remove or ->shutdown will get called first, we cannot really guarantee even for the same driver if rebooting will result in the same code path on all platforms. But nonetheless, we need to do something minimally reasonable on ->shutdown too to fix the bug. Of course, the ->remove will do more (a full teardown of the tree, with all data structures freed, and this is why the bug was not caught for so long). The new ->shutdown method is kept separate from dsa_unregister_switch not because we couldn't have unregistered the switch, but simply in the interest of doing something quick and to the point. The big question is: does the DSA switch's ->shutdown get called earlier than the DSA master's ->shutdown? If not, there is still a risk that we might still trigger the WARN_ON in unregister_netdevice that says we are attempting to unregister a net_device which has uppers. That's no good. Although the reference to the master net_device won't physically go away even if DSA's ->shutdown comes afterwards, remember we have a dev_hold on it. The answer to that question lies in this comment above device_link_add: * A side effect of the link creation is re-ordering of dpm_list and the * devices_kset list by moving the consumer device and all devices depending * on it to the ends of these lists (that does not happen to devices that have * not been registered when this function is called). so the fact that DSA uses device_link_add towards its master is not exactly for nothing. device_shutdown() walks devices_kset from the back, so this is our guarantee that DSA's shutdown happens before the master's shutdown. Fixes: 2f1e8ea726e9 ("net: dsa: link interfaces with the DSA master to get rid of lockdep warnings") Link: https://lore.kernel.org/netdev/20210909095324.12978-1-LinoSanfilippo@gmx.de/ Reported-by: Lino Sanfilippo Signed-off-by: Vladimir Oltean Tested-by: Andrew Lunn Signed-off-by: David S. Miller