| This is stpgd service called by the SCST core upon receiving SET TARGET |
| PORT GROUPS command via SCST events subsystem. In turn, stpgd calls |
| external script to actually modify ALUA state as requested by the SET |
| TARGET PORT GROUPS command via cluster manager and SCST sysfs. You can |
| find example of such script in scst_on_stpg file. |
| |
| Reason why such dual stage approach is used is, because there is no way |
| from inside the kernel to control execution of external programs and |
| there is no way to write a service calling IOCTLs on shell. |