[bug report] dlm: avoid blocking receive at the end of recovery

[bug report] dlm: avoid blocking receive at the end of recovery

[Dan Carpenter]

Hello Alexander Aring,

Commit c288745f1d4a ("dlm: avoid blocking receive at the end of
recovery") from Apr 2, 2024 (linux-next), leads to the following
Smatch static checker warning:

    fs/dlm/lock.c:4859 _receive_message()
    warn: sleeping in atomic context

fs/dlm/lock.c
  4851  
  4852          case cpu_to_le32(DLM_MSG_LOOKUP_REPLY):
  4853                  receive_lookup_reply(ls, ms);
  4854                  break;
  4855  
  4856          /* other messages */
  4857  
  4858          case cpu_to_le32(DLM_MSG_PURGE):
  4859                  receive_purge(ls, ms);
                        ^^^^^^^^^^^^^
Does a mutex_lock() so preempt needs to be enabled.

  4860                  break;
  4861  
  4862          default:
  4863                  log_error(ls, "unknown message type %d",
  4864                            le32_to_cpu(ms->m_type));
  4865          }

The problematic call tree is:

dlm_receive_buffer() <- disables preempt
-> dlm_receive_message() <- disables preempt
   -> _receive_message()

That patch moved _receive_message() to be called under the lock.

regards,
dan carpenter