From 2e7f41bd0632312d00d472a73a312218a29ce65b Mon Sep 17 00:00:00 2001 From: Viktor Mihajlovski Date: Thu, 18 Mar 2021 11:03:34 +0100 Subject: [PATCH] udev: fix slot based network names on s390 The s390 PCI driver assigns the hotplug slot name from the function_id attribute of the PCI device using a 8 char hexadecimal format to match the underlying firmware/hypervisor notation. Further, there's always a one-to-one mapping between a PCI function and a hotplug slot, as individual functions can hot plugged even for multi-function devices. As the generic matching code will always try to parse the slot name in /sys/bus/pci/slots as a positive decimal number, either a wrong value might be produced for ID_NET_NAME_SLOT if the slot name consists of decimal numbers only, or none at all if a character in the range from 'a' to 'f' is encountered. Additionally, the generic code assumes that two interfaces share a hotplug slot, if they differ only in the function part of the PCI address. E.g., for an interface with the PCI address dddd:bb:aa.f, it will match the device to the first slot with an address dddd:bb:aa. As more than one slot may have this address for the s390 PCI driver, the wrong slot may be selected. To resolve this we're adding a new naming schema version with the flag NAMING_SLOT_FUNCTION_ID, which enables the correct matching of hotplug slots if the device has an attribute named function_id. The ID_NET_NAME_SLOT property will only be produced if there's a file /sys/bus/pci/slots/ where matches the value of /sys/bus/pci/devices/.../function_id in 8 char hex notation. Fixes #19016 See also #19078 Related: #1939914 (cherry picked from commit a496a238e8ee66ce25ad13a3f46549b2e2e979fc) --- man/systemd.net-naming-scheme.xml | 10 +++++++++ src/udev/udev-builtin-net_id.c | 34 +++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+) diff --git a/man/systemd.net-naming-scheme.xml b/man/systemd.net-naming-scheme.xml index fe1aa4b654..e42c93eaad 100644 --- a/man/systemd.net-naming-scheme.xml +++ b/man/systemd.net-naming-scheme.xml @@ -313,6 +313,16 @@ Same as naming scheme rhel-8.4. + + rhel-8.7 + + PCI hotplug slot names for the s390 PCI driver are a hexadecimal representation + of the function_id device attribute. This attribute is now used to build the + ID_NET_NAME_SLOT. Before that, all slot names were parsed as decimal + numbers, which could either result in an incorrect value of the ID_NET_NAME_SLOT + property or none at all. + + Note that latest may be used to denote the latest scheme known to this particular version of systemd. diff --git a/src/udev/udev-builtin-net_id.c b/src/udev/udev-builtin-net_id.c index 386d74ca5e..b57227a09f 100644 --- a/src/udev/udev-builtin-net_id.c +++ b/src/udev/udev-builtin-net_id.c @@ -126,6 +126,7 @@ typedef enum NamingSchemeFlags { NAMING_SR_IOV_V = 1 << 0, /* Use "v" suffix for SR-IOV, see 609948c7043a40008b8299529c978ed8e11de8f6*/ NAMING_NPAR_ARI = 1 << 1, /* Use NPAR "ARI", see 6bc04997b6eab35d1cb9fa73889892702c27be09 */ NAMING_BRIDGE_NO_SLOT = 1 << 9, /* Don't use PCI hotplug slot information if the corresponding device is a PCI bridge */ + NAMING_SLOT_FUNCTION_ID = 1 << 10, /* Use function_id if present to identify PCI hotplug slots */ /* And now the masks that combine the features above */ NAMING_V238 = 0, @@ -137,6 +138,7 @@ typedef enum NamingSchemeFlags { NAMING_RHEL_8_4 = NAMING_V239|NAMING_BRIDGE_NO_SLOT, NAMING_RHEL_8_5 = NAMING_RHEL_8_4, NAMING_RHEL_8_6 = NAMING_RHEL_8_4, + NAMING_RHEL_8_7 = NAMING_RHEL_8_4|NAMING_SLOT_FUNCTION_ID, _NAMING_SCHEME_FLAGS_INVALID = -1, } NamingSchemeFlags; @@ -156,6 +158,7 @@ static const NamingScheme naming_schemes[] = { { "rhel-8.4", NAMING_RHEL_8_4 }, { "rhel-8.5", NAMING_RHEL_8_5 }, { "rhel-8.6", NAMING_RHEL_8_6 }, + { "rhel-8.7", NAMING_RHEL_8_7 }, /* … add more schemes here, as the logic to name devices is updated … */ }; @@ -477,6 +480,37 @@ static int dev_pci_slot(struct udev_device *dev, struct netnames *names) { hotplug_slot_dev = names->pcidev; while (hotplug_slot_dev) { + if (!udev_device_get_sysname(hotplug_slot_dev)) + continue; + + /* The /function_id attribute is unique to the s390 PCI driver. + If present, we know that the slot's directory name for this device is + /sys/bus/pci/XXXXXXXX/ where XXXXXXXX is the fixed length 8 hexadecimal + character string representation of function_id. + Therefore we can short cut here and just check for the existence of + the slot directory. As this directory has to exist, we're emitting a + debug message for the unlikely case it's not found. + Note that the domain part of doesn't belong to the slot name here + because there's a 1-to-1 relationship between PCI function and its hotplug + slot. + */ + if (naming_scheme_has(NAMING_SLOT_FUNCTION_ID)) { + attr = udev_device_get_sysattr_value(hotplug_slot_dev, "function_id"); + if (attr) { + int function_id; + _cleanup_free_ char *str; + + if (safe_atoi(attr, &function_id) >= 0 && + asprintf(&str, "%s/%08x/", slots, function_id) >= 0 && + access(str, R_OK) == 0) { + hotplug_slot = function_id; + domain = 0; + } else + log_debug("No matching slot for function_id (%s).", attr); + break; + } + } + FOREACH_DIRENT_ALL(dent, dir, break) { int i, r; char str[PATH_MAX];