kernel/linux.git/net/dsa, branch linux-5.9.y

net: mscc: ocelot: add locking for the port TX timestamp ID

2020-09-18T20:52:33+00:00

The ocelot_port->ts_id is used to: (a) populate skb->cb[0] for matching the TX timestamp in the PTP IRQ with an skb. (b) populate the REW_OP from the injection header of the ongoing skb. Only then is ocelot_port->ts_id incremented. This is a problem because, at least theoretically, another timestampable skb might use the same ocelot_port->ts_id before that is incremented. Normally all transmit calls are serialized by the netdev transmit spinlock, but in this case, ocelot_port_add_txtstamp_skb() is also called by DSA, which has started declaring the NETIF_F_LLTX feature since commit 2b86cb829976 ("net: dsa: declare lockless TX feature for slave ports"). So the logic of using and incrementing the timestamp id should be atomic per port. The solution is to use the global ocelot_port->ts_id only while protected by the associated ocelot_port->ts_id_lock. That's where we populate skb->cb[0]. Note that for ocelot, ocelot_port_add_txtstamp_skb is called for the actual skb, but for felix, it is called for the skb's clone. That is something which will also be changed in the future. Signed-off-by: Vladimir Oltean Reviewed-by: Horatiu Vultur Reviewed-by: Florian Fainelli Tested-by: Alexandre Belloni Reviewed-by: Alexandre Belloni Signed-off-by: David S. Miller

net: dsa: link interfaces with the DSA master to get rid of lockdep warnings

2020-09-09T02:40:09+00:00

Since commit 845e0ebb4408 ("net: change addr_list_lock back to static key"), cascaded DSA setups (DSA switch port as DSA master for another DSA switch port) are emitting this lockdep warning: ============================================ WARNING: possible recursive locking detected 5.8.0-rc1-00133-g923e4b5032dd-dirty #208 Not tainted -------------------------------------------- dhcpcd/323 is trying to acquire lock: ffff000066dd4268 (&dsa_master_addr_list_lock_key/1){+...}-{2:2}, at: dev_mc_sync+0x44/0x90 but task is already holding lock: ffff00006608c268 (&dsa_master_addr_list_lock_key/1){+...}-{2:2}, at: dev_mc_sync+0x44/0x90 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&dsa_master_addr_list_lock_key/1); lock(&dsa_master_addr_list_lock_key/1); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by dhcpcd/323: #0: ffffdbd1381dda18 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock+0x24/0x30 #1: ffff00006614b268 (_xmit_ETHER){+...}-{2:2}, at: dev_set_rx_mode+0x28/0x48 #2: ffff00006608c268 (&dsa_master_addr_list_lock_key/1){+...}-{2:2}, at: dev_mc_sync+0x44/0x90 stack backtrace: Call trace: dump_backtrace+0x0/0x1e0 show_stack+0x20/0x30 dump_stack+0xec/0x158 __lock_acquire+0xca0/0x2398 lock_acquire+0xe8/0x440 _raw_spin_lock_nested+0x64/0x90 dev_mc_sync+0x44/0x90 dsa_slave_set_rx_mode+0x34/0x50 __dev_set_rx_mode+0x60/0xa0 dev_mc_sync+0x84/0x90 dsa_slave_set_rx_mode+0x34/0x50 __dev_set_rx_mode+0x60/0xa0 dev_set_rx_mode+0x30/0x48 __dev_open+0x10c/0x180 __dev_change_flags+0x170/0x1c8 dev_change_flags+0x2c/0x70 devinet_ioctl+0x774/0x878 inet_ioctl+0x348/0x3b0 sock_do_ioctl+0x50/0x310 sock_ioctl+0x1f8/0x580 ksys_ioctl+0xb0/0xf0 __arm64_sys_ioctl+0x28/0x38 el0_svc_common.constprop.0+0x7c/0x180 do_el0_svc+0x2c/0x98 el0_sync_handler+0x9c/0x1b8 el0_sync+0x158/0x180 Since DSA never made use of the netdev API for describing links between upper devices and lower devices, the dev->lower_level value of a DSA switch interface would be 1, which would warn when it is a DSA master. We can use netdev_upper_dev_link() to describe the relationship between a DSA slave and a DSA master. To be precise, a DSA "slave" (switch port) is an "upper" to a DSA "master" (host port). The relationship is "many uppers to one lower", like in the case of VLAN. So, for that reason, we use the same function as VLAN uses. There might be a chance that somebody will try to take hold of this interface and use it immediately after register_netdev() and before netdev_upper_dev_link(). To avoid that, we do the registration and linkage while holding the RTNL, and we use the RTNL-locked cousin of register_netdev(), which is register_netdevice(). Since this warning was not there when lockdep was using dynamic keys for addr_list_lock, we are blaming the lockdep patch itself. The network stack _has_ been using static lockdep keys before, and it _is_ likely that stacked DSA setups have been triggering these lockdep warnings since forever, however I can't test very old kernels on this particular stacked DSA setup, to ensure I'm not in fact introducing regressions. Fixes: 845e0ebb4408 ("net: change addr_list_lock back to static key") Suggested-by: Cong Wang Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

net: dsa: stop overriding master's ndo_get_phys_port_name

2020-07-23T22:14:58+00:00

The purpose of this override is to give the user an indication of what the number of the CPU port is (in DSA, the CPU port is a hardware implementation detail and not a network interface capable of traffic). However, it has always failed (by design) at providing this information to the user in a reliable fashion. Prior to commit 3369afba1e46 ("net: Call into DSA netdevice_ops wrappers"), the behavior was to only override this callback if it was not provided by the DSA master. That was its first failure: if the DSA master itself was a DSA port or a switchdev, then the user would not see the number of the CPU port in /sys/class/net/eth0/phys_port_name, but the number of the DSA master port within its respective physical switch. But that was actually ok in a way. The commit mentioned above changed that behavior, and now overrides the master's ndo_get_phys_port_name unconditionally. That comes with problems of its own, which are worse in a way. The idea is that it's typical for switchdev users to have udev rules for consistent interface naming. These are based, among other things, on the phys_port_name attribute. If we let the DSA switch at the bottom to start randomly overriding ndo_get_phys_port_name with its own CPU port, we basically lose any predictability in interface naming, or even uniqueness, for that matter. So, there are reasons to let DSA override the master's callback (to provide a consistent interface, a number which has a clear meaning and must not be interpreted according to context), and there are reasons to not let DSA override it (it breaks udev matching for the DSA master). But, there is an alternative method for users to retrieve the number of the CPU port of each DSA switch in the system: $ devlink port pci/0000:00:00.5/0: type eth netdev swp0 flavour physical port 0 pci/0000:00:00.5/2: type eth netdev swp2 flavour physical port 2 pci/0000:00:00.5/4: type notset flavour cpu port 4 spi/spi2.0/0: type eth netdev sw0p0 flavour physical port 0 spi/spi2.0/1: type eth netdev sw0p1 flavour physical port 1 spi/spi2.0/2: type eth netdev sw0p2 flavour physical port 2 spi/spi2.0/4: type notset flavour cpu port 4 spi/spi2.1/0: type eth netdev sw1p0 flavour physical port 0 spi/spi2.1/1: type eth netdev sw1p1 flavour physical port 1 spi/spi2.1/2: type eth netdev sw1p2 flavour physical port 2 spi/spi2.1/3: type eth netdev sw1p3 flavour physical port 3 spi/spi2.1/4: type notset flavour cpu port 4 So remove this duplicated, unreliable and troublesome method. From this patch on, the phys_port_name attribute of the DSA master will only contain information about itself (if at all). If the users need reliable information about the CPU port they're probably using devlink anyway. Signed-off-by: Vladimir Oltean Acked-by: florian Fainelli Signed-off-by: David S. Miller

net: dsa: of: Allow ethernet-ports as encapsulating node

2020-07-22T23:56:43+00:00

Due to unified Ethernet Switch Device Tree Bindings allow for ethernet-ports as encapsulating node as well. Signed-off-by: Kurt Kanzenbach Signed-off-by: David S. Miller

net: dsa: use the ETH_MIN_MTU and ETH_DATA_LEN default values

2020-07-21T01:35:04+00:00

Now that DSA supports MTU configuration, undo the effects of commit 8b1efc0f83f1 ("net: remove MTU limits on a few ether_setup callers") and let DSA interfaces use the default min_mtu and max_mtu specified by ether_setup(). This is more important for min_mtu: since DSA is Ethernet, the minimum MTU is the same as of any other Ethernet interface, and definitely not zero. For the max_mtu, we have a callback through which drivers can override that, if they want to. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: Setup dsa_netdev_ops

2020-07-20T23:48:22+00:00

Now that we have all the infrastructure in place for calling into the dsa_ptr->netdev_ops function pointers, install them when we configure the DSA CPU/management interface and tear them down. The flow is unchanged from before, but now we preserve equality of tests when network device drivers do tests like dev->netdev_ops == &foo_ops which was not the case before since we were allocating an entirely new structure. Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller

net: dsa: felix: create a template for the DSA tags on xmit

2020-07-14T00:40:01+00:00

With this patch we try to kill 2 birds with 1 stone. First of all, some switches that use tag_ocelot.c don't have the exact same bitfield layout for the DSA tags. The destination ports field is different for Seville VSC9953 for example. So the choices are to either duplicate tag_ocelot.c into a new tag_seville.c (sub-optimal) or somehow take into account a supposed ocelot->dest_ports_offset when packing this field into the DSA injection header (again not ideal). Secondly, tag_ocelot.c already needs to memset a 128-bit area to zero and call some packing() functions of dubious performance in the fastpath. And most of the values it needs to pack are pretty much constant (BYPASS=1, SRC_PORT=CPU, DEST=port index). So it would be good if we could improve that. The proposed solution is to allocate a memory area per port at probe time, initialize that with the statically defined bits as per chip hardware revision, and just perform a simpler memcpy in the fastpath. Other alternatives have been analyzed, such as: - Create a separate tag_seville.c: too much code duplication for just 1 bit field difference. - Create a separate DSA_TAG_PROTO_SEVILLE under tag_ocelot.c, just like tag_brcm.c, which would have a separate .xmit function. Again, too much code duplication for just 1 bit field difference. - Allocate the template from the init function of the tag_ocelot.c module, instead of from the driver: couldn't figure out a method of accessing the correct port template corresponding to the correct tagger in the .xmit function. Signed-off-by: Vladimir Oltean Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller

devlink: Replace devlink_port_attrs_set parameters with a struct

2020-07-09T20:15:29+00:00

Currently, devlink_port_attrs_set accepts a long list of parameters, that most of them are devlink port's attributes. Use the devlink_port_attrs struct to replace the relevant parameters. Signed-off-by: Danielle Ratson Reviewed-by: Jiri Pirko Signed-off-by: Ido Schimmel Signed-off-by: David S. Miller

net: dsa: tag_rtl4_a: Implement Realtek 4 byte A tag

2020-07-08T22:36:19+00:00

This implements the known parts of the Realtek 4 byte tag protocol version 0xA, as found in the RTL8366RB DSA switch. It is designated as protocol version 0xA as a different Realtek 4 byte tag format with protocol version 0x9 is known to exist in the Realtek RTL8306 chips. The tag and switch chip lacks public documentation, so the tag format has been reverse-engineered from packet dumps. As only ingress traffic has been available for analysis an egress tag has not been possible to develop (even using educated guesses about bit fields) so this is as far as it gets. It is not known if the switch even supports egress tagging. Excessive attempts to figure out the egress tag format was made. When nothing else worked, I just tried all bit combinations with 0xannp where a is protocol and p is port. I looped through all values several times trying to get a response from ping, without any positive result. Using just these ingress tags however, the switch functionality is vastly improved and the packets find their way into the destination port without any tricky VLAN configuration. On the D-Link DIR-685 the LAN ports now come up and respond to ping without any command line configuration so this is a real improvement for users. Egress packets need to be restricted to the proper target ports using VLAN, which the RTL8366RB DSA switch driver already sets up. Cc: DENG Qingfang Cc: Mauri Sandberg Reviewed-by: Andrew Lunn Reviewed-by: Florian Fainelli Signed-off-by: Linus Walleij Signed-off-by: David S. Miller