/*
* The first kthread assigned to a newly activated partition is the one
* created by XPC HB with which it calls xpc_activating(). XPC hangs on to
* that kthread until the partition is brought down, at which time that kthread
* returns back to XPC HB. (The return of that kthread will signify to XPC HB
* that XPC has dismantled all communication infrastructure for the associated
* partition.) This kthread becomes the channel manager for that partition.
*
* Each active partition has a channel manager, who, besides connecting and
* disconnecting channels, will ensure that each of the partition's connected
* channels has the required number of assigned kthreads to get the work done.
*/
static void
xpc_channel_mgr(struct xpc_partition *part)
{
while (part->act_state != XPC_P_AS_DEACTIVATING ||
atomic_read(&part->nchannels_active) > 0 ||
!xpc_partition_disengaged(part)) {
xpc_process_sent_chctl_flags(part);
/*
* Wait until we've been requested to activate kthreads or
* all of the channel's message queues have been torn down or
* a signal is pending.
*
* The channel_mgr_requests is set to 1 after being awakened,
* This is done to prevent the channel mgr from making one pass
* through the loop for each request, since he will
* be servicing all the requests in one pass. The reason it's
* set to 1 instead of 0 is so that other kthreads will know
* that the channel mgr is running and won't bother trying to
* wake him up.
*/
atomic_dec(&part->channel_mgr_requests);
(void)wait_event_interruptible(part->channel_mgr_wq,
(atomic_read(&part->channel_mgr_requests) > 0 ||
part->chctl.all_flags != 0 ||
(part->act_state == XPC_P_AS_DEACTIVATING &&
atomic_read(&part->nchannels_active) == 0 &&
xpc_partition_disengaged(part))));
atomic_set(&part->channel_mgr_requests, 1);
}
}
static void
xpc_channel_mgr(struct xpc_partition *part)
{
while (part->act_state != XPC_P_AS_DEACTIVATING ||
atomic_read(&part->nchannels_active) > 0 ||
!xpc_partition_disengaged(part)) {
xpc_process_sent_chctl_flags(part);
/*
*/
atomic_dec(&part->channel_mgr_requests);
(void)wait_event_interruptible(part->channel_mgr_wq,
(atomic_read(&part->channel_mgr_requests) > 0 ||
part->chctl.all_flags != 0 ||
(part->act_state == XPC_P_AS_DEACTIVATING &&
atomic_read(&part->nchannels_active) == 0 &&
xpc_partition_disengaged(part))));
atomic_set(&part->channel_mgr_requests, 1);
}
}