io_uring: always reissue from task_work context

As a safeguard, if we're going to queue async work, do it from task_work
from the original task. This ensures that we can always sanely create
threads, regards of what the reissue context may be.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a4331de..6ba101c 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2060,6 +2060,12 @@ static void io_req_task_queue(struct io_kiocb *req)
        io_req_task_work_add(req);
 }
 
+static void io_req_task_queue_reissue(struct io_kiocb *req)
+{
+       req->io_task_work.func = io_queue_async_work;
+       io_req_task_work_add(req);
+}
+
 static inline void io_queue_next(struct io_kiocb *req)
 {
        struct io_kiocb *nxt = io_req_find_next(req);
@@ -2248,7 +2254,7 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
                    !(req->flags & REQ_F_DONT_REISSUE)) {
                        req->iopoll_completed = 0;
                        req_ref_get(req);
-                       io_queue_async_work(req);
+                       io_req_task_queue_reissue(req);
                        continue;
                }
 
@@ -2771,7 +2777,7 @@ static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
                req->flags &= ~REQ_F_REISSUE;
                if (io_resubmit_prep(req)) {
                        req_ref_get(req);
-                       io_queue_async_work(req);
+                       io_req_task_queue_reissue(req);
                } else {
                        int cflags = 0;