Commit-ID: fd1a5b04dfb899f84ddeb8acdaea6b98283df1e5
Gitweb: https://git.kernel.org/tip/fd1a5b04dfb899f84ddeb8acdaea6b98283df1e5
Author: Byungchul Park <byungchul.park@xxxxxxx>
AuthorDate: Wed, 25 Oct 2017 17:56:04 +0900
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 25 Oct 2017 12:19:03 +0200
workqueue: Remove now redundant lock acquisitions wrt. workqueue flushes
The workqueue code added manual lock acquisition annotations to catch
deadlocks.
After lockdepcrossrelease was introduced, some of those became redundant,
since wait_for_completion() already does the acquisition and tracking.
Remove the duplicate annotations.
Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: amir73il@xxxxxxxxx
Cc: axboe@xxxxxxxxx
Cc: darrick.wong@xxxxxxxxxx
Cc: david@xxxxxxxxxxxxx
Cc: hch@xxxxxxxxxxxxx
Cc: idryomov@xxxxxxxxx
Cc: johan@xxxxxxxxxx
Cc: johannes.berg@xxxxxxxxx
Cc: kernel-team@xxxxxxx
Cc: linux-block@xxxxxxxxxxxxxxx
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-xfs@xxxxxxxxxxxxxxx
Cc: oleg@xxxxxxxxxx
Cc: tj@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1508921765-15396-9-git-send-email-byungchul.park@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/workqueue.h | 4 ++--
kernel/workqueue.c | 19 +++----------------
2 files changed, 5 insertions(+), 18 deletions(-)
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 1c49431..c8a572c 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -218,7 +218,7 @@ static inline unsigned int work_static(struct work_struct *work) { return 0; }
\
__init_work((_work), _onstack); \
(_work)->data = (atomic_long_t) WORK_DATA_INIT(); \
- lockdep_init_map(&(_work)->lockdep_map, #_work, &__key, 0); \
+ lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \
INIT_LIST_HEAD(&(_work)->entry); \
(_work)->func = (_func); \
} while (0)
@@ -398,7 +398,7 @@ __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
static struct lock_class_key __key; \
const char *__lock_name; \
\
- __lock_name = #fmt#args; \
+ __lock_name = "(wq_completion)"#fmt#args; \
\
__alloc_workqueue_key((fmt), (flags), (max_active), \
&__key, __lock_name, ##args); \
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 39831b2..160fdc6 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2497,15 +2497,8 @@ static void insert_wq_barrier(struct pool_workqueue *pwq,
INIT_WORK_ONSTACK(&barr->work, wq_barrier_func);
__set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&barr->work));
- /*
- * Explicitly init the crosslock for wq_barrier::done, make its lock
- * key a subkey of the corresponding work. As a result we won't
- * build a dependency between wq_barrier::done and unrelated work.
- */
- lockdep_init_map_crosslock((struct lockdep_map *)&barr->done.map,
- "(complete)wq_barr::done",
- target->lockdep_map.key, 1);
- __init_completion(&barr->done);
+ init_completion_map(&barr->done, &target->lockdep_map);
+
barr->task = current;
/*
@@ -2611,16 +2604,13 @@ void flush_workqueue(struct workqueue_struct *wq)
struct wq_flusher this_flusher = {
.list = LIST_HEAD_INIT(this_flusher.list),
.flush_color = -1,
- .done = COMPLETION_INITIALIZER_ONSTACK(this_flusher.done),
+ .done = COMPLETION_INITIALIZER_ONSTACK_MAP(this_flusher.done, wq->lockdep_map),
};
int next_color;
if (WARN_ON(!wq_online))
return;
- lock_map_acquire(&wq->lockdep_map);
- lock_map_release(&wq->lockdep_map);
-
mutex_lock(&wq->mutex);
/*
@@ -2883,9 +2873,6 @@ bool flush_work(struct work_struct *work)
if (WARN_ON(!wq_online))
return false;
- lock_map_acquire(&work->lockdep_map);
- lock_map_release(&work->lockdep_map);
-
if (start_flush_work(work, &barr)) {
wait_for_completion(&barr.done);
destroy_work_on_stack(&barr.work);
--
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