Adding a single direct buffer is a very common case. Introduce an optimized function for that.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com> --- drivers/char/hw_random/virtio-rng.c | 2 +- drivers/char/virtio_console.c | 4 +- drivers/net/virtio_net.c | 2 +- drivers/rpmsg/virtio_rpmsg_bus.c | 8 +++--- drivers/scsi/virtio_scsi.c | 4 +- drivers/virtio/virtio_balloon.c | 6 ++-- drivers/virtio/virtio_ring.c | 40 +++++++++++++++++++++++++++++++++++ include/linux/virtio.h | 5 ++++ tools/virtio/virtio_test.c | 6 ++-- 9 files changed, 61 insertions(+), 16 deletions(-) diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c index b65c103..8b851ed 100644 --- a/drivers/char/hw_random/virtio-rng.c +++ b/drivers/char/hw_random/virtio-rng.c @@ -47,7 +47,7 @@ static void register_buffer(u8 *buf, size_t size) sg_init_one(&sg, buf, size); /* There should always be room for one buffer. */ - if (virtqueue_add_buf(vq, &sg, 0, 1, buf, GFP_KERNEL) < 0) + if (virtqueue_add_buf_single(vq, &sg, DMA_FROM_DEVICE, buf) < 0) BUG(); virtqueue_kick(vq); diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 684b0d5..62bd945 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -508,7 +508,7 @@ static int add_inbuf(struct virtqueue *vq, struct port_buffer *buf) sg_init_one(sg, buf->buf, buf->size); - ret = virtqueue_add_buf(vq, sg, 0, 1, buf, GFP_ATOMIC); + ret = virtqueue_add_buf_single(vq, sg, DMA_FROM_DEVICE, buf); virtqueue_kick(vq); if (!ret) ret = vq->num_free; @@ -575,7 +575,7 @@ static ssize_t __send_control_msg(struct ports_device *portdev, u32 port_id, vq = portdev->c_ovq; sg_init_one(sg, &cpkt, sizeof(cpkt)); - if (virtqueue_add_buf(vq, sg, 1, 0, &cpkt, GFP_ATOMIC) == 0) { + if (virtqueue_add_buf_single(vq, sg, DMA_TO_DEVICE, &cpkt) == 0) { virtqueue_kick(vq); while (!virtqueue_get_buf(vq, &len)) cpu_relax(); diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 78b6f51..1a5186d 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -509,7 +509,7 @@ static int add_recvbuf_mergeable(struct receive_queue *rq, gfp_t gfp) return -ENOMEM; sg_set_page(rq->sg, page, PAGE_SIZE, 0); - err = virtqueue_add_buf(rq->vq, rq->sg, 0, 1, page, gfp); + err = virtqueue_add_buf_single(rq->vq, rq->sg, DMA_FROM_DEVICE, page); if (err < 0) give_pages(rq, page); diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c index f1e3239..3008987 100644 --- a/drivers/rpmsg/virtio_rpmsg_bus.c +++ b/drivers/rpmsg/virtio_rpmsg_bus.c @@ -763,7 +763,7 @@ int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst, mutex_lock(&vrp->tx_lock); /* add message to the remote processor's virtqueue */ - err = virtqueue_add_buf(vrp->svq, &sg, 1, 0, msg, GFP_KERNEL); + err = virtqueue_add_buf_single(vrp->svq, &sg, DMA_TO_DEVICE, msg); if (err) { /* * need to reclaim the buffer here, otherwise it's lost @@ -845,7 +845,7 @@ static void rpmsg_recv_done(struct virtqueue *rvq) sg_init_one(&sg, msg, RPMSG_BUF_SIZE); /* add the buffer back to the remote processor's virtqueue */ - err = virtqueue_add_buf(vrp->rvq, &sg, 0, 1, msg, GFP_KERNEL); + err = virtqueue_add_buf_single(vrp->rvq, &sg, DMA_FROM_DEVICE, msg); if (err < 0) { dev_err(dev, "failed to add a virtqueue buffer: %d\n", err); return; @@ -976,8 +976,8 @@ static int rpmsg_probe(struct virtio_device *vdev) sg_init_one(&sg, cpu_addr, RPMSG_BUF_SIZE); - err = virtqueue_add_buf(vrp->rvq, &sg, 0, 1, cpu_addr, - GFP_KERNEL); + err = virtqueue_add_buf_single(vrp->rvq, &sg, DMA_FROM_DEVICE, + cpu_addr); WARN_ON(err); /* sanity check; this can't really happen */ } diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index 6b752f7..887902e 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -220,8 +220,8 @@ static int virtscsi_kick_event(struct virtio_scsi *vscsi, spin_lock_irqsave(&vscsi->event_vq.vq_lock, flags); - err = virtqueue_add_buf(vscsi->event_vq.vq, &sg, 0, 1, event_node, - GFP_ATOMIC); + err = virtqueue_add_buf_single(vscsi->event_vq.vq, &sg, + DMA_FROM_DEVICE, event_node); if (!err) virtqueue_kick(vscsi->event_vq.vq); diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 797e1c7..c280948 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -108,7 +108,7 @@ static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq) sg_init_one(&sg, vb->pfns, sizeof(vb->pfns[0]) * vb->num_pfns); /* We should always be able to add one buffer to an empty queue. */ - if (virtqueue_add_buf(vq, &sg, 1, 0, vb, GFP_KERNEL) < 0) + if (virtqueue_add_buf_single(vq, &sg, DMA_TO_DEVICE, vb) < 0) BUG(); virtqueue_kick(vq); @@ -256,7 +256,7 @@ static void stats_handle_request(struct virtio_balloon *vb) if (!virtqueue_get_buf(vq, &len)) return; sg_init_one(&sg, vb->stats, sizeof(vb->stats)); - if (virtqueue_add_buf(vq, &sg, 1, 0, vb, GFP_KERNEL) < 0) + if (virtqueue_add_buf_single(vq, &sg, DMA_TO_DEVICE, vb) < 0) BUG(); virtqueue_kick(vq); } @@ -341,7 +341,7 @@ static int init_vqs(struct virtio_balloon *vb) * use it to signal us later. */ sg_init_one(&sg, vb->stats, sizeof vb->stats); - if (virtqueue_add_buf(vb->stats_vq, &sg, 1, 0, vb, GFP_KERNEL) + if (virtqueue_add_buf_single(vb->stats_vq, &sg, DMA_TO_DEVICE, vb) < 0) BUG(); virtqueue_kick(vb->stats_vq); diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 64184e5..b803cf7 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -181,6 +181,48 @@ static int vring_add_indirect(struct vring_virtqueue *vq, } /** + * virtqueue_add_buf_single - expose a single scatterlist entry to other end + * @vq: the struct virtqueue we're talking about. + * @sg: the description of the buffer. + * @dir: whether the buffer will be written or read by the device + * @data: the token identifying the buffer. + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). No allocations are performed. + * + * Returns zero or a negative error (ENOSPC). + */ +int virtqueue_add_buf_single(struct virtqueue *_vq, + struct scatterlist *sg, + enum dma_data_direction dir, + void *data) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + struct vring_desc *tail; + int ret; + + /* Always direct, the gfp argument is not used. */ + ret = virtqueue_start_buf(_vq, data, 1, 1, GFP_ATOMIC); + if (ret < 0) + return ret; + + BUG_ON(vq->indirect_base); + BUG_ON(dir != DMA_FROM_DEVICE && dir != DMA_TO_DEVICE); + + /* The direct case of virtqueue_add_sg, inlined. */ + tail = vq->tail = &vq->vring.desc[vq->free_head]; + tail->flags = dir == DMA_FROM_DEVICE ? VRING_DESC_F_WRITE : 0; + tail->addr = sg_phys(sg); + tail->len = sg->length; + vq->free_head = tail->next; + vq->vq.num_free--; + + virtqueue_end_buf(_vq); + return 0; +} +EXPORT_SYMBOL_GPL(virtqueue_add_buf_single); + +/** * virtqueue_add_buf - expose buffer to other end * @vq: the struct virtqueue we're talking about. * @sg: the description of the buffer(s). diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 43d6bc3..4245bec 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -41,6 +41,11 @@ int virtqueue_add_buf(struct virtqueue *vq, void *data, gfp_t gfp); +int virtqueue_add_buf_single(struct virtqueue *vq, + struct scatterlist *sg, + enum dma_data_direction dir, + void *data); + int virtqueue_start_buf(struct virtqueue *_vq, void *data, unsigned int nents, diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c index fcc9aa2..727b6a1 100644 --- a/tools/virtio/virtio_test.c +++ b/tools/virtio/virtio_test.c @@ -161,9 +161,9 @@ static void run_test(struct vdev_info *dev, struct vq_info *vq, do { if (started < bufs) { sg_init_one(&sl, dev->buf, dev->buf_size); - r = virtqueue_add_buf(vq->vq, &sl, 1, 0, - dev->buf + started, - GFP_ATOMIC); + r = virtqueue_add_buf_single(vq->vq, &sl, + DMA_TO_DEVICE, + dev->buf + started); if (likely(r == 0)) { ++started; virtqueue_kick(vq->vq); -- 1.7.1 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization