The following commit has been merged into the perf/core branch of tip:

Commit-ID: f409530e4db9dd11b88cb7703c97c8f326ff6566 Gitweb: https://git.kernel.org/tip/f409530e4db9dd11b88cb7703c97c8f326ff6566 Author: Frederic Weisbecker frederic@kernel.org AuthorDate: Fri, 21 Jun 2024 11:15:59 +02:00 Committer: Peter Zijlstra peterz@infradead.org CommitterDate: Tue, 09 Jul 2024 13:26:32 +02:00

task_work: Introduce task_work_cancel() again

Re-introduce task_work_cancel(), this time to cancel an actual callback and not *any* callback pointing to a given function. This is going to be needed for perf events event freeing.

Signed-off-by: Frederic Weisbecker frederic@kernel.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240621091601.18227-3-frederic@kernel.org --- include/linux/task_work.h | 1 + kernel/task_work.c | 24 ++++++++++++++++++++++++ 2 files changed, 25 insertions(+)

diff --git a/include/linux/task_work.h b/include/linux/task_work.h index 23ab01a..26b8a47 100644 --- a/include/linux/task_work.h +++ b/include/linux/task_work.h @@ -31,6 +31,7 @@ int task_work_add(struct task_struct *task, struct callback_head *twork, struct callback_head *task_work_cancel_match(struct task_struct *task, bool (*match)(struct callback_head *, void *data), void *data); struct callback_head *task_work_cancel_func(struct task_struct *, task_work_func_t); +bool task_work_cancel(struct task_struct *task, struct callback_head *cb); void task_work_run(void);

static inline void exit_task_work(struct task_struct *task) diff --git a/kernel/task_work.c b/kernel/task_work.c index 54ac240..2134ac8 100644 --- a/kernel/task_work.c +++ b/kernel/task_work.c @@ -136,6 +136,30 @@ task_work_cancel_func(struct task_struct *task, task_work_func_t func) return task_work_cancel_match(task, task_work_func_match, func); }

+static bool task_work_match(struct callback_head *cb, void *data) +{ + return cb == data; +} + +/** + * task_work_cancel - cancel a pending work added by task_work_add() + * @task: the task which should execute the work + * @cb: the callback to remove if queued + * + * Remove a callback from a task's queue if queued. + * + * RETURNS: + * True if the callback was queued and got cancelled, false otherwise. + */ +bool task_work_cancel(struct task_struct *task, struct callback_head *cb) +{ + struct callback_head *ret; + + ret = task_work_cancel_match(task, task_work_match, cb); + + return ret == cb; +} + /** * task_work_run - execute the works added by task_work_add() *