From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LQKvH-0004ei-80 for qemu-devel@nongnu.org; Fri, 23 Jan 2009 07:14:07 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LQKvG-0004eN-Qi for qemu-devel@nongnu.org; Fri, 23 Jan 2009 07:14:06 -0500 Received: from [199.232.76.173] (port=60051 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LQKvG-0004eK-Jz for qemu-devel@nongnu.org; Fri, 23 Jan 2009 07:14:06 -0500 Received: from mx2.redhat.com ([66.187.237.31]:37202) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1LQKvG-0005Sm-5u for qemu-devel@nongnu.org; Fri, 23 Jan 2009 07:14:06 -0500 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n0NCE5GC011606 for ; Fri, 23 Jan 2009 07:14:05 -0500 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n0NCE60R023086 for ; Fri, 23 Jan 2009 07:14:06 -0500 Received: from zweiblum.travel.kraxel.org (vpn-10-167.str.redhat.com [10.32.10.167]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n0NCE4d2006435 for ; Fri, 23 Jan 2009 07:14:05 -0500 Message-ID: <4979B48A.2070003@redhat.com> Date: Fri, 23 Jan 2009 13:14:02 +0100 From: Gerd Hoffmann MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="------------020101060801060507070709" Subject: [Qemu-devel] [patch] qemu iovec: keep track of total size, allow partial copies. Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org This is a multi-part message in MIME format. --------------020101060801060507070709 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi, Keeping track of the total size is trivial for the helpers, and it allows buffer allocation without looping over the iovec once. qemu_iovec_from_buffer got a length parameter (number of bytes to copy) so we can handle partial reads correctly. cheers, Gerd --------------020101060801060507070709 Content-Type: text/plain; name="0002-qemu-iovec-keep-track-of-total-size-allow-partial.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename*0="0002-qemu-iovec-keep-track-of-total-size-allow-partial.patch" >>From 520c69da6d2e52b7f8b1e72d86f7b6ee8e8acad0 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Fri, 23 Jan 2009 12:32:56 +0100 Subject: [PATCH 2/3] qemu iovec: keep track of total size, allow partial copies. Signed-off-by: Gerd Hoffmann --- block.c | 2 +- cutils.c | 15 +++++++++++---- qemu-common.h | 3 ++- 3 files changed, 14 insertions(+), 6 deletions(-) diff --git a/block.c b/block.c index 50ec589..b3d2f12 100644 --- a/block.c +++ b/block.c @@ -1265,7 +1265,7 @@ static void bdrv_aio_rw_vector_cb(void *opaque, int ret) VectorTranslationState *s = opaque; if (!s->is_write) { - qemu_iovec_from_buffer(s->iov, s->bounce); + qemu_iovec_from_buffer(s->iov, s->bounce, s->iov->size); } qemu_free(s->bounce); s->this_aiocb->cb(s->this_aiocb->opaque, ret); diff --git a/cutils.c b/cutils.c index 80a7a1d..1090aa4 100644 --- a/cutils.c +++ b/cutils.c @@ -109,6 +109,7 @@ void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint) qiov->iov = qemu_malloc(alloc_hint * sizeof(struct iovec)); qiov->niov = 0; qiov->nalloc = alloc_hint; + qiov->size = 0; } void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len) @@ -119,6 +120,7 @@ void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len) } qiov->iov[qiov->niov].iov_base = base; qiov->iov[qiov->niov].iov_len = len; + qiov->size += len; ++qiov->niov; } @@ -138,13 +140,18 @@ void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf) } } -void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf) +void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf, size_t count) { const uint8_t *p = (const uint8_t *)buf; + size_t copy; int i; - for (i = 0; i < qiov->niov; ++i) { - memcpy(qiov->iov[i].iov_base, p, qiov->iov[i].iov_len); - p += qiov->iov[i].iov_len; + for (i = 0; i < qiov->niov && count; ++i) { + copy = count; + if (copy > qiov->iov[i].iov_len) + copy = qiov->iov[i].iov_len; + memcpy(qiov->iov[i].iov_base, p, copy); + p += copy; + count -= copy; } } diff --git a/qemu-common.h b/qemu-common.h index ae773e0..42d5e49 100644 --- a/qemu-common.h +++ b/qemu-common.h @@ -195,13 +195,14 @@ typedef struct QEMUIOVector { struct iovec *iov; int niov; int nalloc; + size_t size; } QEMUIOVector; void qemu_iovec_init(QEMUIOVector *qiov, int alloc_hint); void qemu_iovec_add(QEMUIOVector *qiov, void *base, size_t len); void qemu_iovec_destroy(QEMUIOVector *qiov); void qemu_iovec_to_buffer(QEMUIOVector *qiov, void *buf); -void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf); +void qemu_iovec_from_buffer(QEMUIOVector *qiov, const void *buf, size_t count); #endif /* dyngen-exec.h hack */ -- 1.6.1 --------------020101060801060507070709--