From 2c8ec0095e6fd2e72879d4915ff8a9e5c0664d0b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Michal=20Sekleta=CC=81r?= Date: Mon, 19 Oct 2020 11:10:31 +0200 Subject: [PATCH] udev/net_id: don't generate slot based names if multiple devices might claim the same slot --- man/systemd.net-naming-scheme.xml | 14 ++++++++++++++ src/shared/netif-naming-scheme.c | 1 + src/shared/netif-naming-scheme.h | 2 ++ src/udev/udev-builtin-net_id.c | 29 ++++++++++++++++++++++++++++- 4 files changed, 45 insertions(+), 1 deletion(-) diff --git a/man/systemd.net-naming-scheme.xml b/man/systemd.net-naming-scheme.xml index 324c94dbd9f..b33488b9e4d 100644 --- a/man/systemd.net-naming-scheme.xml +++ b/man/systemd.net-naming-scheme.xml @@ -192,6 +192,9 @@ SR-IOV virtual devices are named based on the name of the parent interface, with a suffix of v and the virtual device number, with any leading zeros removed. The bus number is ignored. + + In some configurations a parent PCI bridge of a given network controller may be associated + with a slot. In such case we don't generate this device property to avoid possible naming conflicts. @@ -354,6 +357,17 @@ multiple similarly named containers (who only differ in container name suffix) should be less likely (but still possible, since the 24bit hash value is very small). + + + v246 + + If the PCI slot is assocated with PCI bridge and that has multiple child network + controllers then all of them might derive the same value of ID_NET_NAME_SLOT + property. That could cause naming conflict if the property is selected as a device name. Now, we detect the + situation, slot - bridge relation, and we don't produce the ID_NET_NAME_SLOT property to + avoid possible naming conflict. + + Note that latest may be used to denote the latest scheme known (to this diff --git a/src/shared/netif-naming-scheme.c b/src/shared/netif-naming-scheme.c index 710b6376daf..338ff661f39 100644 --- a/src/shared/netif-naming-scheme.c +++ b/src/shared/netif-naming-scheme.c @@ -12,6 +12,7 @@ static const NamingScheme naming_schemes[] = { { "v241", NAMING_V241 }, { "v243", NAMING_V243 }, { "v245", NAMING_V245 }, + { "v246", NAMING_V246 }, /* … add more schemes here, as the logic to name devices is updated … */ }; diff --git a/src/shared/netif-naming-scheme.h b/src/shared/netif-naming-scheme.h index 6fb26d5cab4..e12464b6a34 100644 --- a/src/shared/netif-naming-scheme.h +++ b/src/shared/netif-naming-scheme.h @@ -31,6 +31,7 @@ typedef enum NamingSchemeFlags { NAMING_NETDEVSIM = 1 << 6, /* Generate names for netdevsim devices, see eaa9d507d855 */ NAMING_LABEL_NOPREFIX = 1 << 7, /* Don't prepend ID_NET_LABEL_ONBOARD with interface type prefix */ NAMING_NSPAWN_LONG_HASH = 1 << 8, /* Shorten nspawn interfaces by including 24bit hash, instead of simple truncation */ + NAMING_BRIDGE_NO_SLOT = 1 << 9, /* Don't use PCI hotplug slot information if the corresponding device is a PCI bridge */ /* And now the masks that combine the features above */ NAMING_V238 = 0, @@ -39,6 +40,7 @@ typedef enum NamingSchemeFlags { NAMING_V241 = NAMING_V240 | NAMING_STABLE_VIRTUAL_MACS, NAMING_V243 = NAMING_V241 | NAMING_NETDEVSIM | NAMING_LABEL_NOPREFIX, NAMING_V245 = NAMING_V243 | NAMING_NSPAWN_LONG_HASH, + NAMING_V246 = NAMING_V245 | NAMING_BRIDGE_NO_SLOT, _NAMING_SCHEME_FLAGS_INVALID = -1, } NamingSchemeFlags; diff --git a/src/udev/udev-builtin-net_id.c b/src/udev/udev-builtin-net_id.c index b88133e37d1..d3db37a8e01 100644 --- a/src/udev/udev-builtin-net_id.c +++ b/src/udev/udev-builtin-net_id.c @@ -243,6 +243,25 @@ static bool is_pci_ari_enabled(sd_device *dev) { return streq(a, "1"); } +static bool is_pci_bridge(sd_device *dev) { + const char *v, *p; + + if (sd_device_get_sysattr_value(dev, "modalias", &v) < 0) + return false; + + if (!startswith(v, "pci:")) + return false; + + p = strrchr(v, 's'); + if (!p) + return false; + if (p[1] != 'c') + return false; + + /* PCI device subclass 04 corresponds to PCI bridge */ + return strneq(p + 2, "04", 2); +} + static int dev_pci_slot(sd_device *dev, struct netnames *names) { unsigned long dev_port = 0; unsigned domain, bus, slot, func; @@ -343,10 +362,18 @@ static int dev_pci_slot(sd_device *dev, struct netnames *names) { read_one_line_file(str, &address) >= 0 && startswith(sysname, address)) { hotplug_slot = i; + + /* We found the match between PCI device and slot. However, we won't use the + * slot index if the device is a PCI bridge, because it can have other child + * devices that will try to claim the same index and that would create name + * collision. */ + if (naming_scheme_has(NAMING_BRIDGE_NO_SLOT) && is_pci_bridge(hotplug_slot_dev)) + hotplug_slot = 0; + break; } } - if (hotplug_slot > 0) + if (hotplug_slot >= 0) break; if (sd_device_get_parent_with_subsystem_devtype(hotplug_slot_dev, "pci", NULL, &hotplug_slot_dev) < 0) break;