block: Fix io_context leak after failure of clone with CLONE_IO

With CLONE_IO, parent's io_context->nr_tasks is incremented, but never
decremented whenever copy_process() fails afterwards, which prevents
exit_io_context() from calling IO schedulers exit functions.

Give a task_struct to exit_io_context(), and call exit_io_context() instead of
put_io_context() in copy_process() cleanup path.

Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index dcd041290b2..cbdabb0dd6d 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -66,14 +66,14 @@ static void cfq_exit(struct io_context *ioc)
 }
 
 /* Called by the exitting task */
-void exit_io_context(void)
+void exit_io_context(struct task_struct *task)
 {
         struct io_context *ioc;
 
-        task_lock(current);
-        ioc = current->io_context;
-        current->io_context = NULL;
-        task_unlock(current);
+        task_lock(task);
+        ioc = task->io_context;
+        task->io_context = NULL;
+        task_unlock(task);
 
         if (atomic_dec_and_test(&ioc->nr_tasks)) {
                 if (ioc->aic && ioc->aic->exit)