From 8cca0eea3964b72b14e8c3f88e3a40bef7b9113e Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 29 Jun 2010 10:07:13 +0200 Subject: [PATCH] workqueue: add find_worker_executing_work() and track current_cwq Now that all the workers are tracked by gcwq, we can find which worker is executing a work from gcwq. Implement find_worker_executing_work() and make worker track its current_cwq so that we can find things the other way around. This will be used to implement non-reentrant wqs. Signed-off-by: Tejun Heo --- kernel/workqueue.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index cfb8aa567e17..c276dec75ea4 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -82,6 +82,7 @@ struct worker { }; struct work_struct *current_work; /* L: work being processed */ + struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */ struct list_head scheduled; /* L: scheduled works */ struct task_struct *task; /* I: worker task */ struct global_cwq *gcwq; /* I: the associated gcwq */ @@ -372,6 +373,59 @@ static struct hlist_head *busy_worker_head(struct global_cwq *gcwq, return &gcwq->busy_hash[v]; } +/** + * __find_worker_executing_work - find worker which is executing a work + * @gcwq: gcwq of interest + * @bwh: hash head as returned by busy_worker_head() + * @work: work to find worker for + * + * Find a worker which is executing @work on @gcwq. @bwh should be + * the hash head obtained by calling busy_worker_head() with the same + * work. + * + * CONTEXT: + * spin_lock_irq(gcwq->lock). + * + * RETURNS: + * Pointer to worker which is executing @work if found, NULL + * otherwise. + */ +static struct worker *__find_worker_executing_work(struct global_cwq *gcwq, + struct hlist_head *bwh, + struct work_struct *work) +{ + struct worker *worker; + struct hlist_node *tmp; + + hlist_for_each_entry(worker, tmp, bwh, hentry) + if (worker->current_work == work) + return worker; + return NULL; +} + +/** + * find_worker_executing_work - find worker which is executing a work + * @gcwq: gcwq of interest + * @work: work to find worker for + * + * Find a worker which is executing @work on @gcwq. This function is + * identical to __find_worker_executing_work() except that this + * function calculates @bwh itself. + * + * CONTEXT: + * spin_lock_irq(gcwq->lock). + * + * RETURNS: + * Pointer to worker which is executing @work if found, NULL + * otherwise. + */ +static struct worker *find_worker_executing_work(struct global_cwq *gcwq, + struct work_struct *work) +{ + return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work), + work); +} + /** * insert_work - insert a work into cwq * @cwq: cwq @work belongs to @@ -914,6 +968,7 @@ static void process_one_work(struct worker *worker, struct work_struct *work) debug_work_deactivate(work); hlist_add_head(&worker->hentry, bwh); worker->current_work = work; + worker->current_cwq = cwq; work_color = get_work_color(work); list_del_init(&work->entry); @@ -942,6 +997,7 @@ static void process_one_work(struct worker *worker, struct work_struct *work) /* we're done with it, release */ hlist_del_init(&worker->hentry); worker->current_work = NULL; + worker->current_cwq = NULL; cwq_dec_nr_in_flight(cwq, work_color); } -- 2.20.1