From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35107) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ay6ec-0002Na-RT for qemu-devel@nongnu.org; Wed, 04 May 2016 19:56:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ay6eH-0004LU-Q9 for qemu-devel@nongnu.org; Wed, 04 May 2016 19:56:25 -0400 From: Eric Blake Date: Wed, 4 May 2016 17:55:08 -0600 Message-Id: <1462406126-22946-3-git-send-email-eblake@redhat.com> In-Reply-To: <1462406126-22946-1-git-send-email-eblake@redhat.com> References: <1462406126-22946-1-git-send-email-eblake@redhat.com> Subject: [Qemu-devel] [PATCH v6 02/20] block: Drop private ioctl-only members of BlockRequest List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, kwolf@redhat.com, Stefan Hajnoczi , Fam Zheng , Max Reitz I was thrown by the fact that the public type BlockRequest had an anonymous union, but no obvious discriminator. Turns out that the only client of the second branch of the union was code internal to io.c, and that with a slight abuse of QEMUIOVector* to pass a void* pointer, we can make the public interface less confusing. (Yes, I know that strict C doesn't guarantee that you can cast void* to the wrong type and then back to void* - it only guarantees the reverse direction of the original pointer to void* and back to the original type - but we already have other assumptions throughout the qemu code base that assume that all pointers are interchangeable in representation). Signed-off-by: Eric Blake --- include/block/block.h | 16 ++++------------ block/io.c | 8 +++++--- 2 files changed, 9 insertions(+), 15 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index 0e8b4d1..754aae3 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -334,18 +334,10 @@ void bdrv_aio_cancel_async(BlockAIOCB *acb); typedef struct BlockRequest { /* Fields to be filled by multiwrite caller */ - union { - struct { - int64_t sector; - int nb_sectors; - int flags; - QEMUIOVector *qiov; - }; - struct { - int req; - void *buf; - }; - }; + int64_t sector; + int nb_sectors; + int flags; + QEMUIOVector *qiov; BlockCompletionFunc *cb; void *opaque; diff --git a/block/io.c b/block/io.c index 0db1146..f15c0f4 100644 --- a/block/io.c +++ b/block/io.c @@ -2614,7 +2614,7 @@ static void coroutine_fn bdrv_co_aio_ioctl_entry(void *opaque) { BlockAIOCBCoroutine *acb = opaque; acb->req.error = bdrv_co_do_ioctl(acb->common.bs, - acb->req.req, acb->req.buf); + acb->req.flags, acb->req.qiov); bdrv_co_complete(acb); } @@ -2628,8 +2628,10 @@ BlockAIOCB *bdrv_aio_ioctl(BlockDriverState *bs, acb->need_bh = true; acb->req.error = -EINPROGRESS; - acb->req.req = req; - acb->req.buf = buf; + /* Slight type abuse here, so we don't have to expose extra fields + * in the public struct BlockRequest */ + acb->req.flags = req; + acb->req.qiov = buf; co = qemu_coroutine_create(bdrv_co_aio_ioctl_entry); qemu_coroutine_enter(co, acb); -- 2.5.5