From: Zhengyuan Liu liuzhengyuan@kylinos.cn
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@kernel.dk for his guidance.
Fixes: 31b515106428 ("io_uring: allow workqueue item to handle multiple buffered requests") Signed-off-by: Zhengyuan Liu liuzhengyuan@kylinos.cn Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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);