diff options
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/poll.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/io_uring/poll.c b/io_uring/poll.c index cf6a70bd54e0..32e5fc8365e6 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -223,21 +223,22 @@ enum { IOU_POLL_DONE = 0, IOU_POLL_NO_ACTION = 1, IOU_POLL_REMOVE_POLL_USE_RES = 2, + IOU_POLL_REISSUE = 3, }; /* * All poll tw should go through this. Checks for poll events, manages * references, does rewait, etc. * - * Returns a negative error on failure. IOU_POLL_NO_ACTION when no action require, - * which is either spurious wakeup or multishot CQE is served. - * IOU_POLL_DONE when it's done with the request, then the mask is stored in req->cqe.res. - * IOU_POLL_REMOVE_POLL_USE_RES indicates to remove multishot poll and that the result - * is stored in req->cqe. + * Returns a negative error on failure. IOU_POLL_NO_ACTION when no action + * require, which is either spurious wakeup or multishot CQE is served. + * IOU_POLL_DONE when it's done with the request, then the mask is stored in + * req->cqe.res. IOU_POLL_REMOVE_POLL_USE_RES indicates to remove multishot + * poll and that the result is stored in req->cqe. */ static int io_poll_check_events(struct io_kiocb *req, bool *locked) { - int v, ret; + int v; /* req->task == current here, checking PF_EXITING is safe */ if (unlikely(req->task->flags & PF_EXITING)) @@ -276,10 +277,15 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked) if (!req->cqe.res) { struct poll_table_struct pt = { ._key = req->apoll_events }; req->cqe.res = vfs_poll(req->file, &pt) & req->apoll_events; + /* + * We got woken with a mask, but someone else got to + * it first. The above vfs_poll() doesn't add us back + * to the waitqueue, so if we get nothing back, we + * should be safe and attempt a reissue. + */ + if (unlikely(!req->cqe.res)) + return IOU_POLL_REISSUE; } - - if ((unlikely(!req->cqe.res))) - continue; if (req->apoll_events & EPOLLONESHOT) return IOU_POLL_DONE; @@ -294,7 +300,7 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked) return IOU_POLL_REMOVE_POLL_USE_RES; } } else { - ret = io_poll_issue(req, locked); + int ret = io_poll_issue(req, locked); if (ret == IOU_STOP_MULTISHOT) return IOU_POLL_REMOVE_POLL_USE_RES; if (ret < 0) @@ -330,6 +336,9 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked) poll = io_kiocb_to_cmd(req, struct io_poll); req->cqe.res = mangle_poll(req->cqe.res & poll->events); + } else if (ret == IOU_POLL_REISSUE) { + io_req_task_submit(req, locked); + return; } else if (ret != IOU_POLL_REMOVE_POLL_USE_RES) { req->cqe.res = ret; req_set_fail(req); @@ -342,7 +351,7 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked) if (ret == IOU_POLL_REMOVE_POLL_USE_RES) io_req_task_complete(req, locked); - else if (ret == IOU_POLL_DONE) + else if (ret == IOU_POLL_DONE || ret == IOU_POLL_REISSUE) io_req_task_submit(req, locked); else io_req_defer_failed(req, ret); |