udev: convert the discovery event handler to the kernel support

The kernel will not send us a specific event for discovery but
rather the AEN result code. So expect NVME_AEN=0x70f002 for
discovery log change events.

Also, we don't get the NVME_CTRL_NAME env var anymore as this is
available from the device $kernel.

Signed-off-by: Sagi Grimberg <[email protected]>

Author: sagigrimberg

nvmf-autoconnect/udev-rules/70-nvmf-autoconnect.rules

@@ -6,10 +6,12 @@
 #
 
 # Events from persistent discovery controllers or nvme-fc transport events
-ACTION=="change", SUBSYSTEM=="nvme", ENV{NVME_EVENT}=="discovery",\
-  ENV{NVME_CTRL_NAME}=="*", ENV{NVME_TRTYPE}=="*", ENV{NVME_TRADDR}=="*", \
+# NVME_AEN:
+#   type 0x2 (NOTICE) info 0xf0 (DISCOVERY_LOG_CHANGE) log-page-id 0x70 (DISCOVERY_LOG_PAGE)
+ACTION=="change", SUBSYSTEM=="nvme", ENV{NVME_AEN}=="0x70f002",\
+  ENV{NVME_TRTYPE}=="*", ENV{NVME_TRADDR}=="*", \
   ENV{NVME_TRSVCID}=="*", ENV{NVME_HOST_TRADDR}=="*", \
-  RUN+="/bin/systemctl --no-block start nvmf-connect@--device=$env{NVME_CTRL_NAME}\t--transport=$env{NVME_TRTYPE}\t--traddr=$env{NVME_TRADDR}\t--trsvcid=$env{NVME_TRSVCID}\t--host-traddr=$env{NVME_HOST_TRADDR}.service"
+  RUN+="/bin/systemctl --no-block start nvmf-connect@--device=$kernel\t--transport=$env{NVME_TRTYPE}\t--traddr=$env{NVME_TRADDR}\t--trsvcid=$env{NVME_TRSVCID}\t--host-traddr=$env{NVME_HOST_TRADDR}.service"
 
 # nvme-fc transport generated events (old-style for compatibility)
 ACTION=="change", SUBSYSTEM=="fc", ENV{FC_EVENT}=="nvmediscovery", \