[PATCH 2/3][Disco] virtio: don't allocate vqs when names[i] = NULL

[Colin King]

From: Wei Wang <wei.w.wang at intel.com>

BugLink: http://bugs.launchpad.net/bugs/1811259

Some vqs may not need to be allocated when their related feature bits
are disabled. So callers may pass in such vqs with "names = NULL".
Then we skip such vq allocations.

Signed-off-by: Wei Wang <wei.w.wang at intel.com>
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Wei Wang <wei.w.wang at intel.com>
Signed-off-by: Wei Wang <wei.w.wang at intel.com>
Reviewed-by: Cornelia Huck <cohuck at redhat.com>
Cc: stable at vger.kernel.org
Fixes: 86a559787e6f ("virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT")
(cherry picked from commit a229989d975eb926076307c1f2f5e4c6111768e7
 https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next)
Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 drivers/misc/mic/vop/vop_main.c        |  9 +++++++--
 drivers/remoteproc/remoteproc_virtio.c |  9 +++++++--
 drivers/s390/virtio/virtio_ccw.c       | 12 +++++++++---
 drivers/virtio/virtio_mmio.c           |  9 +++++++--
 4 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/drivers/misc/mic/vop/vop_main.c b/drivers/misc/mic/vop/vop_main.c
index 3633202..02a9aba 100644
--- a/drivers/misc/mic/vop/vop_main.c
+++ b/drivers/misc/mic/vop/vop_main.c
@@ -381,16 +381,21 @@ static int vop_find_vqs(struct virtio_device *dev, unsigned nvqs,
 	struct _vop_vdev *vdev = to_vopvdev(dev);
 	struct vop_device *vpdev = vdev->vpdev;
 	struct mic_device_ctrl __iomem *dc = vdev->dc;
-	int i, err, retry;
+	int i, err, retry, queue_idx = 0;
 
 	/* We must have this many virtqueues. */
 	if (nvqs > ioread8(&vdev->desc->num_vq))
 		return -ENOENT;
 
 	for (i = 0; i < nvqs; ++i) {
+		if (!names[i]) {
+			vqs[i] = NULL;
+			continue;
+		}
+
 		dev_dbg(_vop_dev(vdev), "%s: %d: %s\n",
 			__func__, i, names[i]);
-		vqs[i] = vop_find_vq(dev, i, callbacks[i], names[i],
+		vqs[i] = vop_find_vq(dev, queue_idx++, callbacks[i], names[i],
 				     ctx ? ctx[i] : false);
 		if (IS_ERR(vqs[i])) {
 			err = PTR_ERR(vqs[i]);
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index de21f62..21b22a1 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -153,10 +153,15 @@ static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
 				 const bool * ctx,
 				 struct irq_affinity *desc)
 {
-	int i, ret;
+	int i, ret, queue_idx = 0;
 
 	for (i = 0; i < nvqs; ++i) {
-		vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i],
+		if (!names[i]) {
+			vqs[i] = NULL;
+			continue;
+		}
+
+		vqs[i] = rp_find_vq(vdev, queue_idx++, callbacks[i], names[i],
 				    ctx ? ctx[i] : false);
 		if (IS_ERR(vqs[i])) {
 			ret = PTR_ERR(vqs[i]);
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index c9c57b4..4e1bdd0 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -635,7 +635,7 @@ static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 {
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
 	unsigned long *indicatorp = NULL;
-	int ret, i;
+	int ret, i, queue_idx = 0;
 	struct ccw1 *ccw;
 
 	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
@@ -643,8 +643,14 @@ static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 		return -ENOMEM;
 
 	for (i = 0; i < nvqs; ++i) {
-		vqs[i] = virtio_ccw_setup_vq(vdev, i, callbacks[i], names[i],
-					     ctx ? ctx[i] : false, ccw);
+		if (!names[i]) {
+			vqs[i] = NULL;
+			continue;
+		}
+
+		vqs[i] = virtio_ccw_setup_vq(vdev, queue_idx++, callbacks[i],
+					     names[i], ctx ? ctx[i] : false,
+					     ccw);
 		if (IS_ERR(vqs[i])) {
 			ret = PTR_ERR(vqs[i]);
 			vqs[i] = NULL;
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 4cd9ea5..d9dd0f78 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -468,7 +468,7 @@ static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 {
 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 	unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
-	int i, err;
+	int i, err, queue_idx = 0;
 
 	err = request_irq(irq, vm_interrupt, IRQF_SHARED,
 			dev_name(&vdev->dev), vm_dev);
@@ -476,7 +476,12 @@ static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 		return err;
 
 	for (i = 0; i < nvqs; ++i) {
-		vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i],
+		if (!names[i]) {
+			vqs[i] = NULL;
+			continue;
+		}
+
+		vqs[i] = vm_setup_vq(vdev, queue_idx++, callbacks[i], names[i],
 				     ctx ? ctx[i] : false);
 		if (IS_ERR(vqs[i])) {
 			vm_del_vqs(vdev);
-- 
2.7.4