[PATCH 3/3] io_uring: Fix remove irrelevant req from the task_list

[Muchun Song]

If the process 0 has been initialized io_uring is complete, and
then fork process 1. If process 1 exits and it leads to delete
all reqs from the task_list. If we kill process 0. We will not
send SIGINT signal to the kworker. So we can not remove the req
from the task_list. The io_sq_wq_submit_work() can do that for
us.

Fixes: 1c4404efcf2c ("io_uring: make sure async workqueue is canceled on exit")
Signed-off-by: Muchun Song <songmuc...@bytedance.com>
---
 fs/io_uring.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index adaafe857b074..2b95be09c0dad 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2277,13 +2277,11 @@ static void io_sq_wq_submit_work(struct work_struct 
*work)
                                        break;
                                cond_resched();
                        } while (1);
-end_req:
-                       if (!list_empty(&req->task_list)) {
-                               spin_lock_irq(&ctx->task_lock);
-                               list_del_init(&req->task_list);
-                               spin_unlock_irq(&ctx->task_lock);
-                       }
                }
+end_req:
+               spin_lock_irq(&ctx->task_lock);
+               list_del_init(&req->task_list);
+               spin_unlock_irq(&ctx->task_lock);
 
                /* drop submission reference */
                io_put_req(req);
@@ -3716,15 +3714,16 @@ static int io_uring_fasync(int fd, struct file *file, 
int on)
 static void io_cancel_async_work(struct io_ring_ctx *ctx,
                                 struct files_struct *files)
 {
+       struct io_kiocb *req;
+
        if (list_empty(&ctx->task_list))
                return;
 
        spin_lock_irq(&ctx->task_lock);
-       while (!list_empty(&ctx->task_list)) {
-               struct io_kiocb *req;
 
-               req = list_first_entry(&ctx->task_list, struct io_kiocb, 
task_list);
-               list_del_init(&req->task_list);
+       list_for_each_entry(req, &ctx->task_list, task_list) {
+               if (files && req->files != files)
+                       continue;
 
                /*
                 * The below executes an smp_mb(), which matches with the
@@ -3734,7 +3733,7 @@ static void io_cancel_async_work(struct io_ring_ctx *ctx,
                 */
                smp_store_mb(req->flags, req->flags | REQ_F_CANCEL); /* B */
 
-               if (req->work_task && (!files || req->files == files))
+               if (req->work_task)
                        send_sig(SIGINT, req->work_task, 1);
        }
        spin_unlock_irq(&ctx->task_lock);
-- 
2.11.0