From 4f8efce613a639a3c1e3022c521d6c70b7154de8 Mon Sep 17 00:00:00 2001 Message-Id: <4f8efce613a639a3c1e3022c521d6c70b7154de8.1357726992.git.minovotn@redhat.com> From: Stefan Hajnoczi Date: Wed, 2 Jan 2013 15:02:24 +0100 Subject: [PATCH 01/16] raw-posix: add raw_get_aio_fd() for virtio-blk-data-plane RH-Author: Stefan Hajnoczi Message-id: <1357138959-1918-2-git-send-email-stefanha@redhat.com> Patchwork-id: 45514 O-Subject: [RHEL6.4 qemu-kvm PATCH v5 01/16] raw-posix: add raw_get_aio_fd() for virtio-blk-data-plane Bugzilla: 877836 RH-Acked-by: Laszlo Ersek RH-Acked-by: Michael S. Tsirkin RH-Acked-by: Paolo Bonzini 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(+) Signed-off-by: Michal Novotny --- block.h | 9 +++++++++ block/raw-posix.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+) diff --git a/block.h b/block.h index 1de99f0..ecb4603 100644 --- a/block.h +++ b/block.h @@ -350,6 +350,15 @@ 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 1d44e30..9026161 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -1296,6 +1296,40 @@ 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) { /* -- 1.7.11.7