From de08356f4858628fdffb8bd7e9cceb60c7e08ead Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Thu, 23 Jun 2022 14:24:48 +0100 Subject: [PATCH] io_uring: refactor poll arm error handling __io_arm_poll_handler() errors parsing is a horror, in case it failed it returns 0 and the caller is expected to look at ipt.error, which already led us to a number of problems before. When it returns a valid mask, leave it as it's not, i.e. return 1 and store the mask in ipt.result_mask. In case of a failure that can be handled inline return an error code (negative value), and return 0 if __io_arm_poll_handler() took ownership of the request and will complete it. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/018cacdaef5fe95d7dc56b32e85d752cab7607f6.1655990418.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- io_uring/poll.c | 44 +++++++++++++++++++++----------------------- 1 file changed, 21 insertions(+), 23 deletions(-) diff --git a/io_uring/poll.c b/io_uring/poll.c index 80113b036c88..3f3ae3b1505f 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -435,6 +435,12 @@ static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, (struct io_poll **) &pt->req->async_data); } +/* + * Returns 0 when it's handed over for polling. The caller owns the requests if + * it returns non-zero, but otherwise should not touch it. Negative values + * contain an error code. When the result is >0, the polling has completed + * inline and ipt.result_mask is set to the mask. + */ static int __io_arm_poll_handler(struct io_kiocb *req, struct io_poll *poll, struct io_poll_table *ipt, __poll_t mask) @@ -461,6 +467,17 @@ static int __io_arm_poll_handler(struct io_kiocb *req, atomic_set(&req->poll_refs, 1); mask = vfs_poll(req->file, &ipt->pt) & poll->events; + if (unlikely(ipt->error || !ipt->nr_entries)) { + io_poll_remove_entries(req); + + if (mask && (poll->events & EPOLLET)) { + ipt->result_mask = mask; + return 1; + } else { + return ipt->error ?: -EINVAL; + } + } + if (mask && ((poll->events & (EPOLLET|EPOLLONESHOT)) == (EPOLLET|EPOLLONESHOT))) { io_poll_remove_entries(req); @@ -469,25 +486,12 @@ static int __io_arm_poll_handler(struct io_kiocb *req, return 1; } - if (!mask && unlikely(ipt->error || !ipt->nr_entries)) { - io_poll_remove_entries(req); - if (!ipt->error) - ipt->error = -EINVAL; - return 0; - } - if (req->flags & REQ_F_HASH_LOCKED) io_poll_req_insert_locked(req); else io_poll_req_insert(req); if (mask && (poll->events & EPOLLET)) { - /* can't multishot if failed, just queue the event we've got */ - if (unlikely(ipt->error || !ipt->nr_entries)) { - poll->events |= EPOLLONESHOT; - req->apoll_events |= EPOLLONESHOT; - ipt->error = 0; - } __io_poll_execute(req, mask); return 0; } @@ -582,9 +586,8 @@ int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) io_kbuf_recycle(req, issue_flags); ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask); - if (ret || ipt.error) - return ret ? IO_APOLL_READY : IO_APOLL_ABORTED; - + if (ret) + return ret > 0 ? IO_APOLL_READY : IO_APOLL_ABORTED; trace_io_uring_poll_arm(req, mask, apoll->poll.events); return IO_APOLL_OK; } @@ -815,16 +818,11 @@ int io_poll_add(struct io_kiocb *req, unsigned int issue_flags) req->flags &= ~REQ_F_HASH_LOCKED; ret = __io_arm_poll_handler(req, poll, &ipt, poll->events); - if (ret) { + if (ret > 0) { io_req_set_res(req, ipt.result_mask, 0); return IOU_OK; } - if (ipt.error) { - req_set_fail(req); - return ipt.error; - } - - return IOU_ISSUE_SKIP_COMPLETE; + return ret ?: IOU_ISSUE_SKIP_COMPLETE; } int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)