[SCSI] async: make async_synchronize_full() flush all work regardless of domain
In response to an async related regression James noted:
"My theory is that this is an init problem: The assumption in a lot of
our code is that async_synchronize_full() waits for everything ... even
the domain specific async schedules, which isn't true."
...so make this assumption true.
Each domain, including the default one, registers itself on a global domain
list when work is scheduled. Once all entries complete it exits that
list. Waiting for the list to be empty syncs all in-flight work across
all domains.
Domains can opt-out of global syncing if they are declared as exclusive
ASYNC_DOMAIN_EXCLUSIVE(). All stack-based domains have been declared
exclusive since the domain may go out of scope as soon as the last work
item completes.
Statically declared domains are mostly ok, but async_unregister_domain()
is there to close any theoretical races with pending
async_synchronize_full waiters at module removal time.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Reported-by: Meelis Roos <mroos@linux.ee>
Reported-by: Eldad Zack <eldadzack@gmail.com>
Tested-by: Eldad Zack <eldad@fogrefinery.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/include/linux/async.h b/include/linux/async.h
index 364e7ff..7a24fe9 100644
--- a/include/linux/async.h
+++ b/include/linux/async.h
@@ -46,6 +46,7 @@
extern async_cookie_t async_schedule(async_func_ptr *ptr, void *data);
extern async_cookie_t async_schedule_domain(async_func_ptr *ptr, void *data,
struct async_domain *domain);
+void async_unregister_domain(struct async_domain *domain);
extern void async_synchronize_full(void);
extern void async_synchronize_full_domain(struct async_domain *domain);
extern void async_synchronize_cookie(async_cookie_t cookie);