| Message ID | 20200722224312.2719813-1-olteanv@gmail.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next] net: dsa: stop overriding master's ndo_get_phys_port_name | expand |
On 7/22/20 3:43 PM, Vladimir Oltean wrote: > 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 <olteanv@gmail.com> Acked-by: florian Fainelli <f.fainelli@gmail.com> Thanks
From: Vladimir Oltean <olteanv@gmail.com> Date: Thu, 23 Jul 2020 01:43:12 +0300 > 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 <olteanv@gmail.com> Applied and now there is only one dsa netdev op :-)
diff --git a/include/net/dsa.h b/include/net/dsa.h index 8b4a0f6a017c..42592b250778 100644 --- a/include/net/dsa.h +++ b/include/net/dsa.h @@ -94,8 +94,6 @@ struct dsa_device_ops { struct dsa_netdevice_ops { int (*ndo_do_ioctl)(struct net_device *dev, struct ifreq *ifr, int cmd); - int (*ndo_get_phys_port_name)(struct net_device *dev, char *name, - size_t len); }; #define DSA_TAG_DRIVER_ALIAS "dsa_tag-" @@ -740,33 +738,12 @@ static inline int dsa_ndo_do_ioctl(struct net_device *dev, struct ifreq *ifr, return ops->ndo_do_ioctl(dev, ifr, cmd); } - -static inline int dsa_ndo_get_phys_port_name(struct net_device *dev, - char *name, size_t len) -{ - const struct dsa_netdevice_ops *ops; - int err; - - err = __dsa_netdevice_ops_check(dev); - if (err) - return err; - - ops = dev->dsa_ptr->netdev_ops; - - return ops->ndo_get_phys_port_name(dev, name, len); -} #else static inline int dsa_ndo_do_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) { return -EOPNOTSUPP; } - -static inline int dsa_ndo_get_phys_port_name(struct net_device *dev, - char *name, size_t len) -{ - return -EOPNOTSUPP; -} #endif void dsa_unregister_switch(struct dsa_switch *ds); diff --git a/net/core/dev.c b/net/core/dev.c index 19f1abc26fcd..062a00fdca9b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -98,7 +98,6 @@ #include <net/busy_poll.h> #include <linux/rtnetlink.h> #include <linux/stat.h> -#include <net/dsa.h> #include <net/dst.h> #include <net/dst_metadata.h> #include <net/pkt_sched.h> @@ -8603,10 +8602,6 @@ int dev_get_phys_port_name(struct net_device *dev, const struct net_device_ops *ops = dev->netdev_ops; int err; - err = dsa_ndo_get_phys_port_name(dev, name, len); - if (err == 0 || err != -EOPNOTSUPP) - return err; - if (ops->ndo_get_phys_port_name) { err = ops->ndo_get_phys_port_name(dev, name, len); if (err != -EOPNOTSUPP) diff --git a/net/dsa/master.c b/net/dsa/master.c index 0c980b2c48c9..6189c4dca6bc 100644 --- a/net/dsa/master.c +++ b/net/dsa/master.c @@ -186,17 +186,6 @@ static void dsa_master_get_strings(struct net_device *dev, uint32_t stringset, } } -static int dsa_master_get_phys_port_name(struct net_device *dev, - char *name, size_t len) -{ - struct dsa_port *cpu_dp = dev->dsa_ptr; - - if (snprintf(name, len, "p%d", cpu_dp->index) >= len) - return -EINVAL; - - return 0; -} - static int dsa_master_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) { struct dsa_port *cpu_dp = dev->dsa_ptr; @@ -228,7 +217,6 @@ static int dsa_master_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) static const struct dsa_netdevice_ops dsa_netdev_ops = { .ndo_do_ioctl = dsa_master_ioctl, - .ndo_get_phys_port_name = dsa_master_get_phys_port_name, }; static int dsa_master_ethtool_setup(struct net_device *dev)
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 <olteanv@gmail.com> --- This is the moral v2 of https://patchwork.ozlabs.org/project/netdev/patch/20200722205348.2688142-1-olteanv@gmail.com/ include/net/dsa.h | 23 ----------------------- net/core/dev.c | 5 ----- net/dsa/master.c | 12 ------------ 3 files changed, 40 deletions(-)