[PATCH] kernel: export task_work_add

[Ming Lei <ming.lei@redhat.com>]

Firstly task_work_add() is used in several drivers. In ublk driver's
usage, request batching submission can only be applied with task_work_add,
and usually get better IOPS.

Secondly from this API's definition, the added work is always run in
the task context, and when task is exiting, either the work is rejected
to be added, or drained in do_exit(). In this way, not see obvious
disadvantage or potential issue by exporting it for module's usage.

So export it, then ublk driver can get simplified, meantime with better
performance.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 kernel/task_work.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/task_work.c b/kernel/task_work.c
index dff75bcde151..5f9a42a388f1 100644
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -73,6 +73,7 @@ int task_work_add(struct task_struct *task, struct callback_head *work,
 
 	return 0;
 }
+EXPORT_SYMBOL_GPL(task_work_add);
 
 /**
  * task_work_cancel_match - cancel a pending work added by task_work_add()
-- 
2.31.1