| 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. |