From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2348587-1516652662-2-1005853905129383468 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 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=arctest; t=1516652662; b=SBJzSNfyfDq7nw7BK1k0hgExmgU3vzTBJ9e7hfW+BWvbh1A kVc42XW7FwlKQ3I9JXgjkv2lvqwsQkIamAZ9xOFRlgH594jpJ2nNLHXfxjQHx1yE RiawOZOLn5ziefty5wGJNb3HBfW2rXnkzDHjCEV+cyZ8WVN94yZUhBWpSCPd9RXj 4DKfXg7Dtf5eh0GkRR8aYmiyhexFwiXptcL8CHsJuI/HxdRH2Y5ZJBENjU70simd 6QpGRPZA8CzQCiKkxpBcmBEAbwOr81KB08qNXq2PhAo+D56QBh2k8EZLpgovicXt rkuYpNOEIrrgIsEMqzVYfapP5FbEwEkvXViWtCQ== 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=1516652662; bh=dOaFgALFfpbuDF/36ScnX0AJ6vJsrhqE0DkrTa7kdfI=; b=i5o+pGH1TSbb 5QUbdTZgUULOmGM0qeEZkkrW/GnVULMWY9KXDUqK6i7/ClhbfOB6aJSc/ksisKXK El//gqatGOAWFeNRc+iPyszkQtM+oHNGPVLQKpZDDD5a1s3la8CkZXKWIwEinEzq y95d3c3ajC8quP4LrvlZo+r7dVtq9iF4f2tGl5J0o9HEjKfCaWFQkAD1R3fGsT8G MIqdtcbo8I2UmE+VkuYIXG++9xM69JMdrCp24R3ai+pKsGtMgX+oX9LYoxeEo5kR pukdFOJE3y8ZxIIo1JMDLG198jKkMrkoYT0VUDc5Kv1m9eiTE1BTQ/Gbrwx535Nc ruRzhl5JpQ== 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=oMJ5tLwg 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 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=oMJ5tLwg 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 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751478AbeAVUXo (ORCPT ); Mon, 22 Jan 2018 15:23:44 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:32929 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751036AbeAVUNe (ORCPT ); Mon, 22 Jan 2018 15:13:34 -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, 22 Jan 2018 21:12:21 +0100 Message-Id: <20180122201243.31610-15-hch@lst.de> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20180122201243.31610-1-hch@lst.de> References: <20180122201243.31610-1-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