From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: [PATCH 08/16] virtio_ring: virtqueue_add_outbuf / virtqueue_add_inbuf. Date: Tue, 19 Feb 2013 18:26:26 +1030 Message-ID: <1361260594-601-9-git-send-email-rusty@rustcorp.com.au> References: <1361260594-601-1-git-send-email-rusty@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1361260594-601-1-git-send-email-rusty@rustcorp.com.au> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Paolo Bonzini Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, "Michael S. Tsirkin" List-Id: virtualization@lists.linuxfoundation.org These are specialized versions of virtqueue_add_buf(), which cover over 50% of cases and are far clearer. In particular, the scatterlists passed to these functions don't have to be clean (ie. we ignore end markers). FIXME: I'm not sure about the unclean sglist bit. I had a more ambitious one which conditionally ignored end markers in the iterator, but it was ugly and I suspect this is just as fast. Maybe we should just fix all the drivers? Signed-off-by: Rusty Russell --- drivers/virtio/virtio_ring.c | 58 ++++++++++++++++++++++++++++++++++++++++++ include/linux/virtio.h | 10 ++++++++ 2 files changed, 68 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index c537385..fb282b5 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -345,6 +345,64 @@ int virtqueue_add_sgs(struct virtqueue *_vq, EXPORT_SYMBOL_GPL(virtqueue_add_sgs); /** + * virtqueue_add_outbuf - expose output buffers to other end + * @vq: the struct virtqueue we're talking about. + * @sgs: array of scatterlists (need not be terminated!) + * @num: the number of scatterlists readable by other side + * @data: the token identifying the buffer. + * @gfp: how to do memory allocations (if necessary). + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * Returns zero or a negative error (ie. ENOSPC, ENOMEM). + */ +int virtqueue_add_outbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp) +{ + unsigned int i; + + /* We're about to iterate, so this is pretty cheap. */ + for (i = 0; i < num - 1; i++) + sg_unmark_end(sg + i); + sg_mark_end(sg + i); + + return virtqueue_add(vq, &sg, num, 1, 0, data, gfp); +} +EXPORT_SYMBOL_GPL(virtqueue_add_outbuf); + +/** + * virtqueue_add_inbuf - expose input buffers to other end + * @vq: the struct virtqueue we're talking about. + * @sgs: array of scatterlists (need not be terminated!) + * @num: the number of scatterlists writable by other side + * @data: the token identifying the buffer. + * @gfp: how to do memory allocations (if necessary). + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * Returns zero or a negative error (ie. ENOSPC, ENOMEM). + */ +int virtqueue_add_inbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp) +{ + unsigned int i; + + /* We're about to iterate, so this is pretty cheap. */ + for (i = 0; i < num - 1; i++) + sg_unmark_end(sg + i); + sg_mark_end(sg + i); + + return virtqueue_add(vq, &sg, num, 0, 1, data, gfp); +} +EXPORT_SYMBOL_GPL(virtqueue_add_inbuf); + +/** * virtqueue_kick_prepare - first half of split virtqueue_kick call. * @vq: the struct virtqueue * diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 6eff15b..b442500 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -40,6 +40,16 @@ int virtqueue_add_buf(struct virtqueue *vq, void *data, gfp_t gfp); +int virtqueue_add_outbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp); + +int virtqueue_add_inbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp); + int virtqueue_add_sgs(struct virtqueue *vq, struct scatterlist *sgs[], unsigned int out_sgs, -- 1.7.10.4 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932269Ab3BSIFX (ORCPT ); Tue, 19 Feb 2013 03:05:23 -0500 Received: from ozlabs.org ([203.10.76.45]:48451 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758244Ab3BSICs (ORCPT ); Tue, 19 Feb 2013 03:02:48 -0500 From: Rusty Russell To: Paolo Bonzini Cc: Rusty Russell , Asias He , "Michael S. Tsirkin" , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH 08/16] virtio_ring: virtqueue_add_outbuf / virtqueue_add_inbuf. Date: Tue, 19 Feb 2013 18:26:26 +1030 Message-Id: <1361260594-601-9-git-send-email-rusty@rustcorp.com.au> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1361260594-601-1-git-send-email-rusty@rustcorp.com.au> References: <1361260594-601-1-git-send-email-rusty@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org These are specialized versions of virtqueue_add_buf(), which cover over 50% of cases and are far clearer. In particular, the scatterlists passed to these functions don't have to be clean (ie. we ignore end markers). FIXME: I'm not sure about the unclean sglist bit. I had a more ambitious one which conditionally ignored end markers in the iterator, but it was ugly and I suspect this is just as fast. Maybe we should just fix all the drivers? Signed-off-by: Rusty Russell --- drivers/virtio/virtio_ring.c | 58 ++++++++++++++++++++++++++++++++++++++++++ include/linux/virtio.h | 10 ++++++++ 2 files changed, 68 insertions(+) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index c537385..fb282b5 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -345,6 +345,64 @@ int virtqueue_add_sgs(struct virtqueue *_vq, EXPORT_SYMBOL_GPL(virtqueue_add_sgs); /** + * virtqueue_add_outbuf - expose output buffers to other end + * @vq: the struct virtqueue we're talking about. + * @sgs: array of scatterlists (need not be terminated!) + * @num: the number of scatterlists readable by other side + * @data: the token identifying the buffer. + * @gfp: how to do memory allocations (if necessary). + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * Returns zero or a negative error (ie. ENOSPC, ENOMEM). + */ +int virtqueue_add_outbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp) +{ + unsigned int i; + + /* We're about to iterate, so this is pretty cheap. */ + for (i = 0; i < num - 1; i++) + sg_unmark_end(sg + i); + sg_mark_end(sg + i); + + return virtqueue_add(vq, &sg, num, 1, 0, data, gfp); +} +EXPORT_SYMBOL_GPL(virtqueue_add_outbuf); + +/** + * virtqueue_add_inbuf - expose input buffers to other end + * @vq: the struct virtqueue we're talking about. + * @sgs: array of scatterlists (need not be terminated!) + * @num: the number of scatterlists writable by other side + * @data: the token identifying the buffer. + * @gfp: how to do memory allocations (if necessary). + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * Returns zero or a negative error (ie. ENOSPC, ENOMEM). + */ +int virtqueue_add_inbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp) +{ + unsigned int i; + + /* We're about to iterate, so this is pretty cheap. */ + for (i = 0; i < num - 1; i++) + sg_unmark_end(sg + i); + sg_mark_end(sg + i); + + return virtqueue_add(vq, &sg, num, 0, 1, data, gfp); +} +EXPORT_SYMBOL_GPL(virtqueue_add_inbuf); + +/** * virtqueue_kick_prepare - first half of split virtqueue_kick call. * @vq: the struct virtqueue * diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 6eff15b..b442500 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -40,6 +40,16 @@ int virtqueue_add_buf(struct virtqueue *vq, void *data, gfp_t gfp); +int virtqueue_add_outbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp); + +int virtqueue_add_inbuf(struct virtqueue *vq, + struct scatterlist sg[], unsigned int num, + void *data, + gfp_t gfp); + int virtqueue_add_sgs(struct virtqueue *vq, struct scatterlist *sgs[], unsigned int out_sgs, -- 1.7.10.4