From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3454413-1521618581-2-5334707816847157877 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='de', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-api-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1521618580; b=VQrdKZIu+Mhtfw2YVXe8Rl+OmFh8GuaEeH0wACelnq4saVV 5oiqCszyVhfqtPBfy7hv526usO92OwlgUhv7KEyv6MU55qZ1DrNzS9VOUnHcLqtD j5yhX6aa+6oNZvHSHdSSTPee/BU2uPoSoNaDDiFCiVTvbgyfKO3suv4hZzzVLI8O kyRjomdol327F0Z/D3A4KdNLXBTA7xI7CDKHNOBsEeVJl5MR9P5oneQCM1Bjl5ZP 8oaYRS9mV0DxmI8ueyeyzSR2lg2rztb8jx2uKgg0n2DlCVTNUpWXPJ5BlwH2Yhvl wDaw6wRdBv5dp2e/bkn8kuMsIwBz2Ks3Dr3XS2Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:sender:list-id; s=arctest; t=1521618580; bh=YoU8HrOT8eaqn+Ls+Vmg3TGUBDTkYA4qyA7cYLQiBto=; b=qOx6T+zV9rSz EtuNkrehV77wzRhbDm4NGIfHCXEVKVLEsdUETEn0y7A3o+qIWfsHryoWOvy0jSmL Ppg7QhP3uajw/7GXUpTzpRwqffcJe9zhAxLWRJNTwTvI30atwTdlnFQkuM4hXeGY 9TkaqiMt+oCdXFHDHos3K9Y5D0vRr5us9v0nEduql15mFKw88Rog4TuA/yHe0X+t T2PO48Z1PrPK9kUpUOGXrI1RuuGCDqwDi4/kj22C7eI+UlDKX9QYGWt01Gp0hUAa +B7aY+WFLKfzrfO3Q842kd+kVvSAHzD6rSTfPT/AcmFjdaUu+PquRxacIOvU7rO2 BGvpV8YlZA== ARC-Authentication-Results: i=1; mx5.messagingengine.com; arc=none (no signatures found); dkim=fail (message has been altered, 2048-bit rsa key sha256) header.d=infradead.org header.i=@infradead.org header.b=LIL+vp6w x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=bombadil.20170209; dmarc=none (p=none,has-list-id=yes,d=none) header.from=lst.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lst.de header.result=pass header_is_org_domain=yes; x-vs=clean score=0 state=0 Authentication-Results: mx5.messagingengine.com; arc=none (no signatures found); dkim=fail (message has been altered, 2048-bit rsa key sha256) header.d=infradead.org header.i=@infradead.org header.b=LIL+vp6w x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=bombadil.20170209; dmarc=none (p=none,has-list-id=yes,d=none) header.from=lst.de; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=lst.de header.result=pass header_is_org_domain=yes; x-vs=clean score=0 state=0 X-ME-VSCategory: clean Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751943AbeCUHlH (ORCPT ); Wed, 21 Mar 2018 03:41:07 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:47874 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751921AbeCUHlD (ORCPT ); Wed, 21 Mar 2018 03:41:03 -0400 From: Christoph Hellwig To: viro@zeniv.linux.org.uk Cc: Avi Kivity , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 06/28] aio: implement IOCB_CMD_POLL Date: Wed, 21 Mar 2018 08:40:10 +0100 Message-Id: <20180321074032.14211-7-hch@lst.de> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20180321074032.14211-1-hch@lst.de> References: <20180321074032.14211-1-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Simple one-shot poll through the io_submit() interface. To poll for a file descriptor the application should submit an iocb of type IOCB_CMD_POLL. It will poll the fd for the events specified in the the first 32 bits of the aio_buf field of the iocb. Unlike poll or epoll without EPOLLONESHOT this interface always works in one shot mode, that is once the iocb is completed, it will have to be resubmitted. Signed-off-by: Christoph Hellwig Acked-by: Jeff Moyer --- fs/aio.c | 102 ++++++++++++++++++++++++++++++++++++++++++- include/uapi/linux/aio_abi.h | 6 +-- 2 files changed, 103 insertions(+), 5 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 79d3eb3d2dd9..38b408129697 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -5,6 +5,7 @@ * Implements an efficient asynchronous io interface. * * Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved. + * Copyright 2018 Christoph Hellwig. * * See ../COPYING for licensing terms. */ @@ -162,10 +163,18 @@ struct fsync_iocb { bool datasync; }; +struct poll_iocb { + struct file *file; + __poll_t events; + struct wait_queue_head *head; + struct wait_queue_entry wait; +}; + struct aio_kiocb { union { struct kiocb rw; struct fsync_iocb fsync; + struct poll_iocb poll; }; struct kioctx *ki_ctx; @@ -1590,7 +1599,6 @@ static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync) return -EINVAL; if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags) return -EINVAL; - req->file = fget(iocb->aio_fildes); if (unlikely(!req->file)) return -EBADF; @@ -1609,6 +1617,96 @@ static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync) return ret; } +static void __aio_complete_poll(struct poll_iocb *req, __poll_t mask) +{ + fput(req->file); + aio_complete(container_of(req, struct aio_kiocb, poll), + mangle_poll(mask), 0); +} + +static void aio_complete_poll(struct poll_iocb *req, __poll_t mask) +{ + struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll); + + if (!(iocb->flags & AIO_IOCB_CANCELLED)) + __aio_complete_poll(req, mask); +} + +static int aio_poll_cancel(struct kiocb *rw) +{ + struct aio_kiocb *iocb = container_of(rw, struct aio_kiocb, rw); + + remove_wait_queue(iocb->poll.head, &iocb->poll.wait); + __aio_complete_poll(&iocb->poll, 0); /* no events to report */ + return 0; +} + +static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, + void *key) +{ + struct poll_iocb *req = container_of(wait, struct poll_iocb, wait); + struct file *file = req->file; + __poll_t mask = key_to_poll(key); + + assert_spin_locked(&req->head->lock); + + /* for instances that support it check for an event match first: */ + if (mask && !(mask & req->events)) + return 0; + + mask = vfs_poll_mask(file, req->events); + if (!mask) + return 0; + + __remove_wait_queue(req->head, &req->wait); + aio_complete_poll(req, mask); + return 1; +} + +static ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb) +{ + struct poll_iocb *req = &aiocb->poll; + unsigned long flags; + __poll_t mask; + + /* reject any unknown events outside the normal event mask. */ + if ((u16)iocb->aio_buf != iocb->aio_buf) + return -EINVAL; + /* reject fields that are not defined for poll */ + if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags) + return -EINVAL; + + req->events = demangle_poll(iocb->aio_buf) | POLLERR | POLLHUP; + req->file = fget(iocb->aio_fildes); + if (unlikely(!req->file)) + return -EBADF; + + req->head = vfs_get_poll_head(req->file, req->events); + if (!req->head) { + fput(req->file); + return -EINVAL; /* same as no support for IOCB_CMD_POLL */ + } + if (IS_ERR(req->head)) { + mask = PTR_TO_POLL(req->head); + goto done; + } + + init_waitqueue_func_entry(&req->wait, aio_poll_wake); + + spin_lock_irqsave(&req->head->lock, flags); + mask = vfs_poll_mask(req->file, req->events); + if (!mask) { + __kiocb_set_cancel_fn(aiocb, aio_poll_cancel, + AIO_IOCB_DELAYED_CANCEL); + __add_wait_queue(req->head, &req->wait); + } + spin_unlock_irqrestore(&req->head->lock, flags); +done: + if (mask) + aio_complete_poll(req, mask); + return -EIOCBQUEUED; +} + static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, struct iocb *iocb, bool compat) { @@ -1677,6 +1775,8 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, break; case IOCB_CMD_FDSYNC: ret = aio_fsync(&req->fsync, iocb, true); + case IOCB_CMD_POLL: + ret = aio_poll(req, iocb); break; default: pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode); diff --git a/include/uapi/linux/aio_abi.h b/include/uapi/linux/aio_abi.h index 2c0a3415beee..ed0185945bb2 100644 --- a/include/uapi/linux/aio_abi.h +++ b/include/uapi/linux/aio_abi.h @@ -39,10 +39,8 @@ enum { IOCB_CMD_PWRITE = 1, IOCB_CMD_FSYNC = 2, IOCB_CMD_FDSYNC = 3, - /* These two are experimental. - * IOCB_CMD_PREADX = 4, - * IOCB_CMD_POLL = 5, - */ + /* 4 was the experimental IOCB_CMD_PREADX */ + IOCB_CMD_POLL = 5, IOCB_CMD_NOOP = 6, IOCB_CMD_PREADV = 7, IOCB_CMD_PWRITEV = 8, -- 2.14.2