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systemd/SOURCES/0480-udev-net_id-don-t-gene...

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5.9 KiB

From bb6114af097da0cd9c5081e42db718559130687f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michal=20Sekleta=CC=81r?= <msekleta@redhat.com>
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
(cherry picked from commit 2c8ec0095e6fd2e72879d4915ff8a9e5c0664d0b)
Resolves: #1827462
---
man/systemd.net-naming-scheme.xml | 15 ++++++++++-
src/udev/udev-builtin-net_id.c | 41 ++++++++++++++++++++++++++-----
2 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/man/systemd.net-naming-scheme.xml b/man/systemd.net-naming-scheme.xml
index a12cc3c460..10e71dcb15 100644
--- a/man/systemd.net-naming-scheme.xml
+++ b/man/systemd.net-naming-scheme.xml
@@ -176,7 +176,10 @@
<para>SR-IOV virtual devices are named based on the name of the parent interface, with a suffix of
<constant>v</constant> and the virtual device number, with any leading zeros removed. The bus
- number is ignored. This device type is found in IBM PowerVMs.</para>
+ number is ignored.</para>
+
+ <para>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.</para>
</varlistentry>
<varlistentry>
@@ -288,6 +291,16 @@
<para>Same as naming scheme <constant>rhel-8.0</constant>.</para>
</varlistentry>
+ <varlistentry>
+ <term><constant>rhel-8.4</constant></term>
+
+ <listitem><para>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 <varname>ID_NET_NAME_SLOT</varname>
+ 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 <varname>ID_NET_NAME_SLOT</varname> property to
+ avoid possible naming conflict.</para></listitem>
+ </varlistentry>
+
<para>Note that <constant>latest</constant> may be used to denote the latest scheme known (to this
particular version of systemd.</para>
</variablelist>
diff --git a/src/udev/udev-builtin-net_id.c b/src/udev/udev-builtin-net_id.c
index ede24dee41..d8c56b62bb 100644
--- a/src/udev/udev-builtin-net_id.c
+++ b/src/udev/udev-builtin-net_id.c
@@ -124,6 +124,7 @@ typedef enum NamingSchemeFlags {
/* First, the individual features */
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 */
/* And now the masks that combine the features above */
NAMING_V238 = 0,
@@ -132,6 +133,7 @@ typedef enum NamingSchemeFlags {
NAMING_RHEL_8_1 = NAMING_V239,
NAMING_RHEL_8_2 = NAMING_V239,
NAMING_RHEL_8_3 = NAMING_V239,
+ NAMING_RHEL_8_4 = NAMING_V239|NAMING_BRIDGE_NO_SLOT,
_NAMING_SCHEME_FLAGS_INVALID = -1,
} NamingSchemeFlags;
@@ -389,6 +391,26 @@ static bool is_pci_ari_enabled(struct udev_device *dev) {
return streq_ptr(udev_device_get_sysattr_value(dev, "ari_enabled"), "1");
}
+static bool is_pci_bridge(struct udev_device *dev) {
+ const char *v, *p;
+
+ v = udev_device_get_sysattr_value(dev, "modalias");
+ if (!v)
+ 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(struct udev_device *dev, struct netnames *names) {
struct udev *udev = udev_device_get_udev(names->pcidev);
unsigned domain, bus, slot, func, dev_port = 0;
@@ -461,16 +483,23 @@ static int dev_pci_slot(struct udev_device *dev, struct netnames *names) {
if (r < 0 || i <= 0)
continue;
+ /* match slot address with device by stripping the function */
if (snprintf_ok(str, sizeof str, "%s/%s/address", slots, dent->d_name) &&
- read_one_line_file(str, &address) >= 0)
- /* match slot address with device by stripping the function */
- if (startswith(udev_device_get_sysname(hotplug_slot_dev), address))
- hotplug_slot = i;
+ read_one_line_file(str, &address) >= 0 &&
+ startswith(udev_device_get_sysname(hotplug_slot_dev), 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;
- if (hotplug_slot > 0)
break;
+ }
}
- if (hotplug_slot > 0)
+ if (hotplug_slot >= 0)
break;
rewinddir(dir);
hotplug_slot_dev = udev_device_get_parent_with_subsystem_devtype(hotplug_slot_dev, "pci", NULL);