From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59A37C282C2 for ; Thu, 7 Feb 2019 22:12:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28B0E21907 for ; Thu, 7 Feb 2019 22:12:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726642AbfBGWMv (ORCPT ); Thu, 7 Feb 2019 17:12:51 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56194 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726622AbfBGWMv (ORCPT ); Thu, 7 Feb 2019 17:12:51 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E7639C0495BB; Thu, 7 Feb 2019 22:12:50 +0000 (UTC) Received: from segfault.boston.devel.redhat.com (segfault.boston.devel.redhat.com [10.19.60.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DCA1C600D7; Thu, 7 Feb 2019 22:12:49 +0000 (UTC) From: Jeff Moyer To: Jens Axboe Cc: linux-aio@kvack.org, linux-block@vger.kernel.org, linux-api@vger.kernel.org, hch@lst.de, avi@scylladb.com, jannh@google.com, viro@ZenIV.linux.org.uk Subject: Re: [PATCH 16/18] io_uring: add support for IORING_OP_POLL References: <20190207195552.22770-1-axboe@kernel.dk> <20190207195552.22770-17-axboe@kernel.dk> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 Date: Thu, 07 Feb 2019 17:12:49 -0500 In-Reply-To: <20190207195552.22770-17-axboe@kernel.dk> (Jens Axboe's message of "Thu, 7 Feb 2019 12:55:50 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 07 Feb 2019 22:12:51 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi, Jens, > +static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe) > +{ [...] > + /* one for removal from waitqueue, one for this function */ > + refcount_set(&req->refs, 2); > + > + mask = vfs_poll(poll->file, &ipt.pt) & poll->events; > + if (unlikely(!poll->head)) { > + /* we did not manage to set up a waitqueue, done */ > + goto out; > + } > + > + spin_lock_irq(&ctx->completion_lock); > + spin_lock(&poll->head->lock); > + if (poll->woken) { > + /* wake_up context handles the rest */ > + mask = 0; > + ipt.error = 0; > + } else if (mask || ipt.error) { > + /* if we get an error or a mask we are done */ > + WARN_ON_ONCE(list_empty(&poll->wait.entry)); > + list_del_init(&poll->wait.entry); > + } else { > + /* actually waiting for an event */ > + list_add_tail(&req->list, &ctx->cancel_list); > + } > + spin_unlock(&poll->head->lock); > + spin_unlock_irq(&ctx->completion_lock); > + > +out: > + if (unlikely(ipt.error)) { > + if (!(flags & IOSQE_FIXED_FILE)) > + fput(poll->file); > + return ipt.error; > + } You need to drop the reference count on the req inside that if block. -Jeff > + > + if (mask) > + io_poll_complete(req, mask); > + io_free_req(req); > + return 0; > +}