From: Zhengyuan Liu <liuzhengyuan@xxxxxxxxxx>
commit f7b76ac9d17e16e44feebb6d2749fec92bfd6dd4 upstream.
We could 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 if we didn't process the req in async list.
Thanks to Jens Axboe <axboe@xxxxxxxxx> for his guidance.
Fixes: 31b515106428 ("io_uring: allow workqueue item to handle multiple buffered requests")
Signed-off-by: Zhengyuan Liu <liuzhengyuan@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/io_uring.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -331,6 +331,9 @@ struct io_kiocb {
#define REQ_F_SEQ_PREV 8 /* sequential with previous */
#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_LINK_DONE 128 /* linked sqes done */
+#define REQ_F_FAIL_LINK 256 /* fail rest of links */
u64 user_data;
u32 error; /* iopoll result from callback */
u32 sequence;
@@ -1698,6 +1701,10 @@ restart:
/* 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)) {
@@ -1745,6 +1752,7 @@ restart:
}
}
+out:
if (cur_mm) {
set_fs(old_fs);
unuse_mm(cur_mm);
