async: keep pending tasks on async_domain and remove async_pending
Async kept single global pending list and per-domain running lists.
When an async item is queued, it's put on the global pending list.
The item is moved to the per-domain running list when its execution
starts.
At this point, this design complicates execution and synchronization
without bringing any benefit. The list only matters for
synchronization which doesn't care whether a given async item is
pending or executing. Also, global synchronization is done by
iterating through all active registered async_domains, so the global
async_pending list doesn't help anything either.
Rename async_domain->running to async_domain->pending and put async
items directly there and remove when execution completes. This
simplifies lowest_in_progress() a lot - the first item on the pending
list is the one with the lowest cookie, and async_run_entry_fn()
doesn't have to mess with moving the item from pending to running.
After the change, whether a domain is empty or not can be trivially
determined by looking at async_domain->pending. Remove
async_domain->count and use list_empty() on pending instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <djbw@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/async.h b/include/linux/async.h
index 34ff5c6..a2e3f18 100644
--- a/include/linux/async.h
+++ b/include/linux/async.h
@@ -19,8 +19,7 @@
typedef void (async_func_ptr) (void *data, async_cookie_t cookie);
struct async_domain {
struct list_head node;
- struct list_head running;
- int count;
+ struct list_head pending;
unsigned registered:1;
};
@@ -29,8 +28,7 @@
*/
#define ASYNC_DOMAIN(_name) \
struct async_domain _name = { .node = LIST_HEAD_INIT(_name.node), \
- .running = LIST_HEAD_INIT(_name.running), \
- .count = 0, \
+ .pending = LIST_HEAD_INIT(_name.pending), \
.registered = 1 }
/*
@@ -39,8 +37,7 @@
*/
#define ASYNC_DOMAIN_EXCLUSIVE(_name) \
struct async_domain _name = { .node = LIST_HEAD_INIT(_name.node), \
- .running = LIST_HEAD_INIT(_name.running), \
- .count = 0, \
+ .pending = LIST_HEAD_INIT(_name.pending), \
.registered = 0 }
extern async_cookie_t async_schedule(async_func_ptr *ptr, void *data);