udev/net_id: don't generate slot based names if multiple devices might claim the same slot

man/systemd.net-naming-scheme.xml

@@ -192,6 +192,9 @@
           <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.</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>
           </listitem>
         </varlistentry>
 
@@ -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).</para></listitem>
         </varlistentry>
+
+        <varlistentry>
+          <term><constant>v246</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>
+
       </variablelist>
 
     <para>Note that <constant>latest</constant> may be used to denote the latest scheme known (to this