From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2624115-1520285940-2-8071869412736533469 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 0.249, 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=1520285938; b=s7A63XgBK4LcTBpECapX7kWPWDH8yJhJxQ6wN5AnaEy4ChR ryJvJ16pA3Jbd+AeLLdmFnNpn9u6+4ndUdTDqAQx9pUlduhc6auuPvt0/ieuG/Cu boF+cAaWu1eQAt3NqbK97u9Y7ss4K/hVUzlIy5vSADnMFdIwb/OKWFldHyVP1eJH mu3YpVbYb3bSseqJ0Fc+uJv3ZVcX56DcD8k645SgNmVwWTbeUfKCINYYmSjgO4ml FHfO2+HjNwKS/ccMyq/lr4aRW3g3jEZeuKET7Wwi7MJj7nH7oi+Ng40PFqvxDdZX 2ktOUNGPpzabFwxLREjHfehHzJBd/FvzzELG4Kg== 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=1520285938; bh=dOaFgALFfpbuDF/36ScnX0AJ6vJsrhqE0DkrTa7kdfI=; b=RMCrFp/dI2zw FI5LAA7wqtT27OKDvB2Jylnhk7yJ5Oq0l0UpVB3jghEkvVlIy6AfUfUlErRj4ZbS H/lV6MWg51szFGimVo+sFCjBiddMKlG2VPmX+bhpLxBMnAMGUfC6bEZW/bIf+72n Rn3iLbYd0KPDc5pFaN7kMMEFBoZhYo9rUTb4kBP3JsVdSXtdU9zW5VBdLeKqeVR/ LLOERTkJLDAemIMewyJ/Ey7YeadETR1Yp0I27guGFdYdcuckOlC190hqNFjHozrd MhjTpSYnbWVHsnnTJsG5Xd/3jUIeRgMfwY/8bX3q8dIQSr9wXFbwo1PtUITNlYnW +6Mh0NShGg== ARC-Authentication-Results: i=1; mx6.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=PaeE5P/4 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-category=clean score=0 state=0; 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 Authentication-Results: mx6.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=PaeE5P/4 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-category=clean score=0 state=0; 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 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752861AbeCEViP (ORCPT ); Mon, 5 Mar 2018 16:38:15 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:60658 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753212AbeCEV1w (ORCPT ); Mon, 5 Mar 2018 16:27:52 -0500 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 14/36] aio: implement IOCB_CMD_POLL Date: Mon, 5 Mar 2018 13:27:21 -0800 Message-Id: <20180305212743.16664-15-hch@lst.de> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20180305212743.16664-1-hch@lst.de> References: <20180305212743.16664-1-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 --- fs/aio.c | 102 +++++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/aio_abi.h | 6 +-- 2 files changed, 104 insertions(+), 4 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index da87cbf7c67a..0bafc4975d51 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. */ @@ -156,9 +157,17 @@ struct kioctx { unsigned id; }; +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 poll_iocb poll; }; struct kioctx *ki_ctx; @@ -1565,6 +1574,96 @@ static ssize_t aio_write(struct kiocb *req, struct iocb *iocb, bool vectored, 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) { @@ -1628,6 +1727,9 @@ static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, case IOCB_CMD_PWRITEV: ret = aio_write(&req->rw, iocb, true, compat); break; + case IOCB_CMD_POLL: + ret = aio_poll(req, iocb); + break; default: pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode); ret = -EINVAL; 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