From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Byungchul Park To: peterz@infradead.org, mingo@kernel.org Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, tj@kernel.org, johannes.berg@intel.com, oleg@redhat.com, amir73il@gmail.com, david@fromorbit.com, darrick.wong@oracle.com, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, hch@infradead.org, idryomov@gmail.com, kernel-team@lge.com Subject: [PATCH v2 2/4] lockdep: Remove unnecessary acquisitions wrt workqueue flush Date: Thu, 19 Oct 2017 16:03:25 +0900 Message-Id: <1508396607-25362-3-git-send-email-byungchul.park@lge.com> In-Reply-To: <1508396607-25362-1-git-send-email-byungchul.park@lge.com> References: <1508392531-11284-1-git-send-email-byungchul.park@lge.com> <1508396607-25362-1-git-send-email-byungchul.park@lge.com> Sender: owner-linux-mm@kvack.org List-ID: The workqueue added manual acquisitions to catch deadlock cases. Now crossrelease was introduced, some of those are redundant, since wait_for_completion() already includes the acquisition for itself. Removed it. Signed-off-by: Byungchul Park --- include/linux/workqueue.h | 4 ++-- kernel/workqueue.c | 20 ++++---------------- 2 files changed, 6 insertions(+), 18 deletions(-) diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index f3c47a0..1455b5e 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -218,7 +218,7 @@ static inline void destroy_delayed_work_on_stack(struct delayed_work *work) { } \ __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, "(complete)"#_work, &__key, 0); \ INIT_LIST_HEAD(&(_work)->entry); \ (_work)->func = (_func); \ } while (0) @@ -399,7 +399,7 @@ enum { static struct lock_class_key __key; \ const char *__lock_name; \ \ - __lock_name = #fmt#args; \ + __lock_name = "(complete)"#fmt#args; \ \ __alloc_workqueue_key((fmt), (flags), (max_active), \ &__key, __lock_name, ##args); \ diff --git a/kernel/workqueue.c b/kernel/workqueue.c index c77fdf6..8cef533 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -2496,15 +2496,8 @@ 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_with_map(&barr->done, &target->lockdep_map); + barr->task = current; /* @@ -2610,16 +2603,14 @@ 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), }; int next_color; + init_completion_with_map(&this_flusher.done, &wq->lockdep_map); + if (WARN_ON(!wq_online)) return; - lock_map_acquire(&wq->lockdep_map); - lock_map_release(&wq->lockdep_map); - mutex_lock(&wq->mutex); /* @@ -2882,9 +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); -- 1.9.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org