[LU-12780] Avoid using ptlrpc_thread where is in't needed

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.15.0
• Assignee: Neil Brown
• Reporter: Neil Brown

Description

Several places in lustre use 'struct ptlrpc_thread' to "help" manage a kthread.

These places are not directly related to ptlrpc, so the naming is not help, and in general the usage of ptlrpc_thread does not improve the code.

By removing the use of ptlrpc_thread - particularly by avoiding startup synchornization and by using kthread_stop/ kthread_should_stop(), I can reduce code size by a couple of hundred lines.

Using the seemly uniform approach of ptlrpc_thread can lead to an impression that these threads are all managed much the same way, but this is not the case.  There is substantial variety on how the threads work and exposing that clear will benefit maintainability.

 

Issue Links

• is related to: LU-13986 livelock is possible in distribute_txn_commit_thread()
• is related to: LU-12511 Prepare lustre for adoption into the linux kernel