From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3845081-1526037652-2-10347718639771251245 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, MAILING_LIST_MULTI -1, RCVD_IN_DNSWL_HI -5, LANGUAGES enro, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', 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=fm2; t= 1526037651; b=JitJikMgE8ee7B5F6LbQFkrfEpLv5FyP2Uqf10lCuoX171whpE wOHebWwe10vxiDdSRapvtTowlAuLKyi8xurf1MGLB6E4VgNmeywOXBomcLrKME1J cRhURoFtZ5GNp1hc/EVnsbeoQh7B8a6a9pu6RNWrZnHAFvNMrGkWZVAtyjSHBDcT tVuL1YdobnB5henBpdUjWBuI9chi9qgiozRpF3TVSWkoDPNvejtubv6WhDoLkVNN JR3B1AKiZzd0oH+11u0dd2Eb+jF6/0Hu5IsfK7UBfaoNlBpAqcQfcSdrU5rRlWS3 iwL7dbUN1EWL0g9iY+7E6q8lSeoWLo9QLyjQ== 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=fm2; t=1526037651; bh= PJ7c0kODGJjajPJhm6lMy/GtBx11DZtVI7n7W2ont/Q=; b=bnWjlSRpS2mrZ8SZ Mrr1KQ//sOcztVcpMYx4xUZK5Te028Z4elnVWZgZYL5NGWkO9NyEQ/U5+F24hrlN S5NdO6ymmFgyb82zhb2NjOxdUKZu5bJoQ0FaHxBgk0k59IMOBFnzrQe816YKJnvC 1zeE3bTsS68lZHZNRKvwqJuC966LyEmCh/LhBreqcQaPG4uGNWnyB8An+PuiRT3G n5sZbsjmI9rsCwHHRQRQT26u/7+A2nqfM0HrBQIEw9SaA7mokO+/AWVT4zPxPwhq swq3YegO7TU0vLzKpSlhXaKrPwLDvHS3q1z/7L2i1SBb7cF14mScJEWQvSCWeMfw qStXSA== ARC-Authentication-Results: i=1; mx4.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=EKVzVDpq 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-cm=none score=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; x-vs=clean score=0 state=0 Authentication-Results: mx4.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=EKVzVDpq 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-cm=none score=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; x-vs=clean score=0 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfC7T/hvIbLKXb4URtBOZoK0V1MiJ7u8RXsixCDstuO9RWW2lPcxg5bSnZbPUO1qTgS4Fy8ZlSUUbC6iaDouXtC6dYzhYRlihgQYAQ66qS2EGp7zGtsBm ho8s4pcgdrz1N3Jumueg7C9qUNvQxnTmp5RgOzu6h1vEfKl7q31wUD9erYm6pFh/i2UWCxB+yXr0zNLdrZxmWpN+Xc/3m1f+d8c+9d8bfN0gUMmkKFM2T9kS X-CM-Analysis: v=2.3 cv=JLoVTfCb c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=VUJBJC2UJ8kA:10 a=20KFwNOVAAAA:8 a=ag1SF4gXAAAA:8 a=yPCof4ZbAAAA:8 a=VwQbUJbxAAAA:8 a=sBy_PAm624FdtEvdJhYA:9 a=x8gzFH9gYPwA:10 a=Yupwre4RP9_Eg_Bd0iYG:22 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753177AbeEKLUa (ORCPT ); Fri, 11 May 2018 07:20:30 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:47306 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753100AbeEKLIk (ORCPT ); Fri, 11 May 2018 07:08:40 -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 10/32] aio: implement IOCB_CMD_POLL Date: Fri, 11 May 2018 13:07:41 +0200 Message-Id: <20180511110803.10910-11-hch@lst.de> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180511110803.10910-1-hch@lst.de> References: <20180511110803.10910-1-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 Reviewed-by: Greg Kroah-Hartman Reviewed-by: Darrick J. Wong --- fs/aio.c | 92 +++++++++++++++++++++++++++++++++++- include/uapi/linux/aio_abi.h | 6 +-- 2 files changed, 93 insertions(+), 5 deletions(-) diff --git a/fs/aio.c b/fs/aio.c index 3afca506c7f0..f2c7674e2151 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. */ @@ -165,10 +166,18 @@ 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; @@ -1569,7 +1578,6 @@ static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync) if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags)) return -EINVAL; - req->file = fget(iocb->aio_fildes); if (unlikely(!req->file)) return -EBADF; @@ -1584,6 +1592,86 @@ static int aio_fsync(struct fsync_iocb *req, struct iocb *iocb, bool datasync) return -EIOCBQUEUED; } +static int aio_poll_cancel(struct aio_kiocb *iocb) +{ + remove_wait_queue(iocb->poll.head, &iocb->poll.wait); + aio_complete(iocb, iocb->poll.file, 0, 0, AIO_COMPLETE_CANCEL); + 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 aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll); + 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 = file->f_op->poll_mask(file, req->events); + if (!mask) + return 0; + + __remove_wait_queue(req->head, &req->wait); + aio_complete(iocb, req->file, mangle_poll(mask), 0, 0); + return 1; +} + +static ssize_t aio_poll(struct aio_kiocb *aiocb, struct iocb *iocb) +{ + struct kioctx *ctx = aiocb->ki_ctx; + 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; + if (!file_has_poll_mask(req->file)) + goto out_fail; + + req->head = req->file->f_op->get_poll_head(req->file, req->events); + if (!req->head) + goto out_fail; + if (IS_ERR(req->head)) { + mask = EPOLLERR; + goto done; + } + + init_waitqueue_func_entry(&req->wait, aio_poll_wake); + aiocb->ki_cancel = aio_poll_cancel; + + spin_lock_irqsave(&ctx->ctx_lock, flags); + list_add_tail(&aiocb->ki_list, &ctx->delayed_cancel_reqs); + spin_unlock(&ctx->ctx_lock); + + spin_lock(&req->head->lock); + mask = req->file->f_op->poll_mask(req->file, req->events); + if (!mask) + __add_wait_queue(req->head, &req->wait); + spin_unlock_irqrestore(&req->head->lock, flags); +done: + if (mask) + aio_complete(aiocb, req->file, mangle_poll(mask), 0, 0); + return -EIOCBQUEUED; +out_fail: + fput(req->file); + return -EINVAL; /* same as no support for IOCB_CMD_POLL */ +} + static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, struct iocb *iocb, bool compat) { @@ -1652,6 +1740,8 @@ 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, -- 2.17.0