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authorJens Axboe <axboe@kernel.dk>2021-04-01 19:53:29 -0600
committerJens Axboe <axboe@kernel.dk>2021-04-11 19:30:25 -0600
commitc7aab1a7c52b82d9afd7e03c398eb03dc2aa0507 (patch)
tree5747e9fde43bf6665d6a82d1f29640a4b966d676 /kernel/task_work.c
parentb2e720ace221f9be75fefdba7d0ebab9d05fc561 (diff)
task_work: add helper for more targeted task_work canceling
The only exported helper we have right now is task_work_cancel(), which cancels any task_work from a given task where func matches the queued work item. This is a bit too coarse for some use cases. Add a task_work_cancel_match() that allows to more specifically target individual work items outside of purely the callback function used. task_work_cancel() can be trivially implemented on top of that, hence do so. Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'kernel/task_work.c')
-rw-r--r--kernel/task_work.c35
1 files changed, 28 insertions, 7 deletions
diff --git a/kernel/task_work.c b/kernel/task_work.c
index 9cde961875c0..e9316198c64b 100644
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -59,18 +59,17 @@ int task_work_add(struct task_struct *task, struct callback_head *work,
}
/**
- * task_work_cancel - cancel a pending work added by task_work_add()
+ * task_work_cancel_match - cancel a pending work added by task_work_add()
* @task: the task which should execute the work
- * @func: identifies the work to remove
- *
- * Find the last queued pending work with ->func == @func and remove
- * it from queue.
+ * @match: match function to call
*
* RETURNS:
* The found work or NULL if not found.
*/
struct callback_head *
-task_work_cancel(struct task_struct *task, task_work_func_t func)
+task_work_cancel_match(struct task_struct *task,
+ bool (*match)(struct callback_head *, void *data),
+ void *data)
{
struct callback_head **pprev = &task->task_works;
struct callback_head *work;
@@ -86,7 +85,7 @@ task_work_cancel(struct task_struct *task, task_work_func_t func)
*/
raw_spin_lock_irqsave(&task->pi_lock, flags);
while ((work = READ_ONCE(*pprev))) {
- if (work->func != func)
+ if (!match(work, data))
pprev = &work->next;
else if (cmpxchg(pprev, work, work->next) == work)
break;
@@ -96,6 +95,28 @@ task_work_cancel(struct task_struct *task, task_work_func_t func)
return work;
}
+static bool task_work_func_match(struct callback_head *cb, void *data)
+{
+ return cb->func == data;
+}
+
+/**
+ * task_work_cancel - cancel a pending work added by task_work_add()
+ * @task: the task which should execute the work
+ * @func: identifies the work to remove
+ *
+ * Find the last queued pending work with ->func == @func and remove
+ * it from queue.
+ *
+ * RETURNS:
+ * The found work or NULL if not found.
+ */
+struct callback_head *
+task_work_cancel(struct task_struct *task, task_work_func_t func)
+{
+ return task_work_cancel_match(task, task_work_func_match, func);
+}
+
/**
* task_work_run - execute the works added by task_work_add()
*