From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:48412) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TbYWb-00064A-7Q for qemu-devel@nongnu.org; Thu, 22 Nov 2012 10:17:14 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TbYWV-0007FZ-2B for qemu-devel@nongnu.org; Thu, 22 Nov 2012 10:17:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:40866) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TbYWU-0007FH-RD for qemu-devel@nongnu.org; Thu, 22 Nov 2012 10:17:02 -0500 From: Stefan Hajnoczi Date: Thu, 22 Nov 2012 16:16:42 +0100 Message-Id: <1353597412-12232-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1353597412-12232-1-git-send-email-stefanha@redhat.com> References: <1353597412-12232-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH v4 01/11] raw-posix: add raw_get_aio_fd() for virtio-blk-data-plane List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Anthony Liguori , "Michael S. Tsirkin" , Blue Swirl , khoa@us.ibm.com, Stefan Hajnoczi , Paolo Bonzini , Asias He 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 722c620..2dc6aaf 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 f2f0404..fc04981 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -1768,6 +1768,40 @@ 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) { /* -- 1.8.0