From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=52662 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PNe1v-0002iC-HE for qemu-devel@nongnu.org; Tue, 30 Nov 2010 23:11:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PNUSG-0005XZ-7a for qemu-devel@nongnu.org; Tue, 30 Nov 2010 12:57:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32819) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PNUSF-0005WH-Qq for qemu-devel@nongnu.org; Tue, 30 Nov 2010 12:57:28 -0500 From: Kevin Wolf Date: Tue, 30 Nov 2010 18:58:09 +0100 Message-Id: <1291139900-20329-6-git-send-email-kwolf@redhat.com> In-Reply-To: <1291139900-20329-1-git-send-email-kwolf@redhat.com> References: <1291139900-20329-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PATCH 05/16] qemu and qemu-xen: support empty write barriers in xen_disk List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: anthony@codemonkey.ws Cc: kwolf@redhat.com, qemu-devel@nongnu.org From: Stefano Stabellini This patch can be applied to both qemu-xen and qemu and adds support for empty write barriers to xen_disk. Signed-off-by: Stefano Stabellini Acked-by: Gerd Hoffmann Signed-off-by: Kevin Wolf --- hw/xen_disk.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/hw/xen_disk.c b/hw/xen_disk.c index 134ac33..85a1c85 100644 --- a/hw/xen_disk.c +++ b/hw/xen_disk.c @@ -181,6 +181,10 @@ static int ioreq_parse(struct ioreq *ioreq) ioreq->prot = PROT_WRITE; /* to memory */ break; case BLKIF_OP_WRITE_BARRIER: + if (!ioreq->req.nr_segments) { + ioreq->presync = 1; + return 0; + } if (!syncwrite) ioreq->presync = ioreq->postsync = 1; /* fall through */ @@ -305,7 +309,7 @@ static int ioreq_runio_qemu_sync(struct ioreq *ioreq) int i, rc, len = 0; off_t pos; - if (ioreq_map(ioreq) == -1) + if (ioreq->req.nr_segments && ioreq_map(ioreq) == -1) goto err; if (ioreq->presync) bdrv_flush(blkdev->bs); @@ -329,6 +333,8 @@ static int ioreq_runio_qemu_sync(struct ioreq *ioreq) break; case BLKIF_OP_WRITE: case BLKIF_OP_WRITE_BARRIER: + if (!ioreq->req.nr_segments) + break; pos = ioreq->start; for (i = 0; i < ioreq->v.niov; i++) { rc = bdrv_write(blkdev->bs, pos / BLOCK_SIZE, @@ -386,7 +392,7 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq) { struct XenBlkDev *blkdev = ioreq->blkdev; - if (ioreq_map(ioreq) == -1) + if (ioreq->req.nr_segments && ioreq_map(ioreq) == -1) goto err; ioreq->aio_inflight++; @@ -403,6 +409,8 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq) case BLKIF_OP_WRITE: case BLKIF_OP_WRITE_BARRIER: ioreq->aio_inflight++; + if (!ioreq->req.nr_segments) + break; bdrv_aio_writev(blkdev->bs, ioreq->start / BLOCK_SIZE, &ioreq->v, ioreq->v.size / BLOCK_SIZE, qemu_aio_complete, ioreq); -- 1.7.2.3