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authorDavid Howells <dhowells@redhat.com>2006-11-22 09:55:48 -0500
committerDavid Howells <dhowells@redhat.com>2006-11-22 09:55:48 -0500
commit65f27f38446e1976cc98fd3004b110fedcddd189 (patch)
tree68f8be93feae31dfa018c22db392a05546b63ee1 /ipc
parent365970a1ea76d81cb1ad2f652acb605f06dae256 (diff)
WorkStruct: Pass the work_struct pointer instead of context data
Pass the work_struct pointer to the work function rather than context data. The work function can use container_of() to work out the data. For the cases where the container of the work_struct may go away the moment the pending bit is cleared, it is made possible to defer the release of the structure by deferring the clearing of the pending bit. To make this work, an extra flag is introduced into the management side of the work_struct. This governs auto-release of the structure upon execution. Ordinarily, the work queue executor would release the work_struct for further scheduling or deallocation by clearing the pending bit prior to jumping to the work function. This means that, unless the driver makes some guarantee itself that the work_struct won't go away, the work function may not access anything else in the work_struct or its container lest they be deallocated.. This is a problem if the auxiliary data is taken away (as done by the last patch). However, if the pending bit is *not* cleared before jumping to the work function, then the work function *may* access the work_struct and its container with no problems. But then the work function must itself release the work_struct by calling work_release(). In most cases, automatic release is fine, so this is the default. Special initiators exist for the non-auto-release case (ending in _NAR). Signed-Off-By: David Howells <dhowells@redhat.com>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/util.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/ipc/util.c b/ipc/util.c
index cd8bb14a431f..a9b7a227b8d4 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -514,6 +514,11 @@ void ipc_rcu_getref(void *ptr)
514 container_of(ptr, struct ipc_rcu_hdr, data)->refcount++; 514 container_of(ptr, struct ipc_rcu_hdr, data)->refcount++;
515} 515}
516 516
517static void ipc_do_vfree(struct work_struct *work)
518{
519 vfree(container_of(work, struct ipc_rcu_sched, work));
520}
521
517/** 522/**
518 * ipc_schedule_free - free ipc + rcu space 523 * ipc_schedule_free - free ipc + rcu space
519 * @head: RCU callback structure for queued work 524 * @head: RCU callback structure for queued work
@@ -528,7 +533,7 @@ static void ipc_schedule_free(struct rcu_head *head)
528 struct ipc_rcu_sched *sched = 533 struct ipc_rcu_sched *sched =
529 container_of(&(grace->data[0]), struct ipc_rcu_sched, data[0]); 534 container_of(&(grace->data[0]), struct ipc_rcu_sched, data[0]);
530 535
531 INIT_WORK(&sched->work, vfree, sched); 536 INIT_WORK(&sched->work, ipc_do_vfree);
532 schedule_work(&sched->work); 537 schedule_work(&sched->work);
533} 538}
534 539