From 07a2159c8dc575745c967499b068209e8926ea79 Mon Sep 17 00:00:00 2001

From: Michal Sekletar <msekleta@redhat.com>

Date: Wed, 23 Mar 2022 17:34:12 +0100

Subject: [PATCH] udev/net_id: avoid slot based names only for single function

 devices

If we have two or more devices that share the same slot but they are

also multifunction then it is OK to use the slot information even if it

is the same for all of them. Name conflict will be avoided because we

will append function number and form names like, ens1f1, ens1f2...

(cherry picked from commit 66425daf2c68793adf24a48a26d58add8662e83f)

Resolves: #2073003

---

 man/systemd.net-naming-scheme.xml |  7 ++++++-

 src/shared/netif-naming-scheme.h  | 31 ++++++++++++++++---------------

 src/udev/udev-builtin-net_id.c    | 11 +++++++++--

 3 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/man/systemd.net-naming-scheme.xml b/man/systemd.net-naming-scheme.xml

index 942ef572ff..73d08b681d 100644

--- a/man/systemd.net-naming-scheme.xml

+++ b/man/systemd.net-naming-scheme.xml

@@ -406,7 +406,12 @@

         <varlistentry>

           <term><constant>rhel-9.0</constant></term>

-          <listitem><para>Same as naming scheme <constant>v250</constant>.</para>

+          <listitem><para>Since version <constant>v247</constant> we no longer set

+          <varname>ID_NET_NAME_SLOT</varname> if we detect that a PCI device associated with a slot is a PCI

+          bridge as that would create naming conflict when there are more child devices on that bridge. Now,

+          this is relaxed and we will use slot information to generate the name based on it but only if

+          the PCI device has multiple functions. This is safe because distinct function number is a part of

+          the device name for multifunction devices.</para>

           </listitem>

         </varlistentry>

diff --git a/src/shared/netif-naming-scheme.h b/src/shared/netif-naming-scheme.h

index f765db6ef2..5c86cb4545 100644

--- a/src/shared/netif-naming-scheme.h

+++ b/src/shared/netif-naming-scheme.h

@@ -22,20 +22,21 @@

  * OS versions, but not fully stabilize them. */

 typedef enum NamingSchemeFlags {

         /* First, the individual features */

-        NAMING_SR_IOV_V            = 1 << 0, /* Use "v" suffix for SR-IOV, see 609948c7043a */

-        NAMING_NPAR_ARI            = 1 << 1, /* Use NPAR "ARI", see 6bc04997b6ea */

-        NAMING_INFINIBAND          = 1 << 2, /* Use "ib" prefix for infiniband, see 938d30aa98df */

-        NAMING_ZERO_ACPI_INDEX     = 1 << 3, /* Use zero acpi_index field, see d81186ef4f6a */

-        NAMING_ALLOW_RERENAMES     = 1 << 4, /* Allow re-renaming of devices, see #9006 */

-        NAMING_STABLE_VIRTUAL_MACS = 1 << 5, /* Use device name to generate MAC, see 6d3646406560 */

-        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 */

-        NAMING_SLOT_FUNCTION_ID    = 1 << 10, /* Use function_id if present to identify PCI hotplug slots */

-        NAMING_16BIT_INDEX         = 1 << 11, /* Allow full 16-bit for the onboard index */

-        NAMING_REPLACE_STRICTLY    = 1 << 12, /* Use udev_replace_ifname() for NAME= rule */

-        NAMING_XEN_VIF             = 1 << 13, /* GEnerate names for Xen netfront devices */

+        NAMING_SR_IOV_V                  = 1 << 0, /* Use "v" suffix for SR-IOV, see 609948c7043a */

+        NAMING_NPAR_ARI                  = 1 << 1, /* Use NPAR "ARI", see 6bc04997b6ea */

+        NAMING_INFINIBAND                = 1 << 2, /* Use "ib" prefix for infiniband, see 938d30aa98df */

+        NAMING_ZERO_ACPI_INDEX           = 1 << 3, /* Use zero acpi_index field, see d81186ef4f6a */

+        NAMING_ALLOW_RERENAMES           = 1 << 4, /* Allow re-renaming of devices, see #9006 */

+        NAMING_STABLE_VIRTUAL_MACS       = 1 << 5, /* Use device name to generate MAC, see 6d3646406560 */

+        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 */

+        NAMING_SLOT_FUNCTION_ID          = 1 << 10, /* Use function_id if present to identify PCI hotplug slots */

+        NAMING_16BIT_INDEX               = 1 << 11, /* Allow full 16-bit for the onboard index */

+        NAMING_REPLACE_STRICTLY          = 1 << 12, /* Use udev_replace_ifname() for NAME= rule */

+        NAMING_XEN_VIF                   = 1 << 13, /* Generate names for Xen netfront devices */

+        NAMING_BRIDGE_MULTIFUNCTION_SLOT = 1 << 14, /* Use PCI hotplug slot information associated with bridge, but only if PCI device is multifunction */

         /* And now the masks that combine the features above */

         NAMING_V238 = 0,

@@ -47,7 +48,7 @@ typedef enum NamingSchemeFlags {

         NAMING_V247 = NAMING_V245 | NAMING_BRIDGE_NO_SLOT,

         NAMING_V249 = NAMING_V247 | NAMING_SLOT_FUNCTION_ID | NAMING_16BIT_INDEX | NAMING_REPLACE_STRICTLY,

         NAMING_V250 = NAMING_V249 | NAMING_XEN_VIF,

-        NAMING_RHEL_9_0 = NAMING_V250,

+        NAMING_RHEL_9_0 = NAMING_V250 | NAMING_BRIDGE_MULTIFUNCTION_SLOT,

         EXTRA_NET_NAMING_SCHEMES

diff --git a/src/udev/udev-builtin-net_id.c b/src/udev/udev-builtin-net_id.c

index 65e003eb15..673ed7a7ca 100644

--- a/src/udev/udev-builtin-net_id.c

+++ b/src/udev/udev-builtin-net_id.c

@@ -451,8 +451,15 @@ static int dev_pci_slot(sd_device *dev, const LinkInfo *info, NetNames *names) {

                                  * 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)) {

-                                        log_device_debug(dev, "Not using slot information because the PCI device is a bridge.");

-                                        return 0;

+                                        if (naming_scheme_has(NAMING_BRIDGE_MULTIFUNCTION_SLOT) && !is_pci_multifunction(names->pcidev)) {

+                                                log_device_debug(dev, "Not using slot information because the PCI device associated with the hotplug slot is a bridge and the PCI device has single function.");

+                                                return 0;

+                                        }

+

+                                        if (!naming_scheme_has(NAMING_BRIDGE_MULTIFUNCTION_SLOT)) {

+                                                log_device_debug(dev, "Not using slot information because the PCI device is a bridge.");

+                                                return 0;

+                                        }

                                 }

                                 break;