From patchwork Wed Dec 19 15:38:02 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 207409 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 5AAC92C007D for ; Thu, 20 Dec 2012 02:38:50 +1100 (EST) Received: from localhost ([::1]:34465 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TlLjM-00048d-Eo for incoming@patchwork.ozlabs.org; Wed, 19 Dec 2012 10:38:48 -0500 Received: from eggs.gnu.org ([208.118.235.92]:60386) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TlLj3-0003kG-5p for qemu-devel@nongnu.org; Wed, 19 Dec 2012 10:38:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TlLj0-0002Cp-CL for qemu-devel@nongnu.org; Wed, 19 Dec 2012 10:38:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:22140) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TlLj0-0002Ci-2o for qemu-devel@nongnu.org; Wed, 19 Dec 2012 10:38:26 -0500 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id qBJFcP2V028763 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 19 Dec 2012 10:38:25 -0500 Received: from localhost (ovpn-112-31.ams2.redhat.com [10.36.112.31]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id qBJFcNmw020478; Wed, 19 Dec 2012 10:38:24 -0500 From: Stefan Hajnoczi To: Date: Wed, 19 Dec 2012 16:38:02 +0100 Message-Id: <1355931499-7912-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1355931499-7912-1-git-send-email-stefanha@redhat.com> References: <1355931499-7912-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Anthony Liguori Subject: [Qemu-devel] [PATCH 01/18] raw-posix: add raw_get_aio_fd() for virtio-blk-data-plane X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org The raw_get_aio_fd() function allows virtio-blk-data-plane to get the file descriptor of a raw image file with Linux AIO enabled. This interface is really a layering violation that can be resolved once the block layer is able to run outside the global mutex - at that point virtio-blk-data-plane will switch from custom Linux AIO code to using the block layer. Signed-off-by: Stefan Hajnoczi --- block.h | 9 +++++++++ block/raw-posix.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+) diff --git a/block.h b/block.h index 893448a..c96f028 100644 --- a/block.h +++ b/block.h @@ -365,6 +365,15 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs); void bdrv_set_in_use(BlockDriverState *bs, int in_use); int bdrv_in_use(BlockDriverState *bs); +#ifdef CONFIG_LINUX_AIO +int raw_get_aio_fd(BlockDriverState *bs); +#else +static inline int raw_get_aio_fd(BlockDriverState *bs) +{ + return -ENOTSUP; +} +#endif + enum BlockAcctType { BDRV_ACCT_READ, BDRV_ACCT_WRITE, diff --git a/block/raw-posix.c b/block/raw-posix.c index abfedbe..634824b 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -1777,6 +1777,40 @@ static BlockDriver bdrv_host_cdrom = { }; #endif /* __FreeBSD__ */ +#ifdef CONFIG_LINUX_AIO +/** + * Return the file descriptor for Linux AIO + * + * This function is a layering violation and should be removed when it becomes + * possible to call the block layer outside the global mutex. It allows the + * caller to hijack the file descriptor so I/O can be performed outside the + * block layer. + */ +int raw_get_aio_fd(BlockDriverState *bs) +{ + BDRVRawState *s; + + if (!bs->drv) { + return -ENOMEDIUM; + } + + if (bs->drv == bdrv_find_format("raw")) { + bs = bs->file; + } + + /* raw-posix has several protocols so just check for raw_aio_readv */ + if (bs->drv->bdrv_aio_readv != raw_aio_readv) { + return -ENOTSUP; + } + + s = bs->opaque; + if (!s->use_aio) { + return -ENOTSUP; + } + return s->fd; +} +#endif /* CONFIG_LINUX_AIO */ + static void bdrv_file_init(void) { /*