We would queue a work for each req in defer and link list without
increasing async_list->cnt, so we shouldn't decrease it while exiting
from workqueue as well as shouldn't process the req in async list.
Thanks to Jens Axboe <axboe@xxxxxxxxx> for his guidance.
Signed-off-by: Zhengyuan Liu <liuzhengyuan@xxxxxxxxxx>
---
fs/io_uring.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7e932c572f26..e554091c713c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -333,7 +333,8 @@ struct io_kiocb {
#define REQ_F_IO_DRAIN 16 /* drain existing IO first */
#define REQ_F_IO_DRAINED 32 /* drain done */
#define REQ_F_LINK 64 /* linked sqes */
-#define REQ_F_FAIL_LINK 128 /* fail rest of links */
+#define REQ_F_LINK_DONE 128 /* linked sqes done */
+#define REQ_F_FAIL_LINK 256 /* fail rest of links */
u64 user_data;
u32 result;
u32 sequence;
@@ -630,6 +631,7 @@ static void io_req_link_next(struct io_kiocb *req)
nxt->flags |= REQ_F_LINK;
}
+ nxt->flags |= REQ_F_LINK_DONE;
INIT_WORK(&nxt->work, io_sq_wq_submit_work);
queue_work(req->ctx->sqo_wq, &nxt->work);
}
@@ -1845,6 +1847,10 @@ static void io_sq_wq_submit_work(struct work_struct *work)
/* async context always use a copy of the sqe */
kfree(sqe);
+ /* req from defer and link list needn't decrease async cnt */
+ if (req->flags & (REQ_F_IO_DRAINED | REQ_F_LINK_DONE))
+ goto out;
+
if (!async_list)
break;
if (!list_empty(&req_list)) {
@@ -1892,6 +1898,7 @@ static void io_sq_wq_submit_work(struct work_struct *work)
}
}
+out:
if (cur_mm) {
set_fs(old_fs);
unuse_mm(cur_mm);
--
2.19.1
