The MMIO transport implementation creates a list of virtqueues for a
virtio device, while the same is already available in the struct
virtio_device.

Don't create a duplicate list, and use the other one instead.

While at it, fix the virtio_device_for_each_vq() macro to accept an
argument like "&vm_dev->vdev" (which currently fails to build).

Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
---
I have tested this with a Xen/Qemu based setup to test guest to host virtio-i2c
communication. Works fine, not sure why this code was added in the first place.

 drivers/virtio/virtio_mmio.c | 52 +++---------------------------------
 include/linux/virtio.h       |  2 +-
 2 files changed, 4 insertions(+), 50 deletions(-)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 5d78c2d572ab..b152a1eca05a 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -65,7 +65,6 @@
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/slab.h>
-#include <linux/spinlock.h>
 #include <linux/virtio.h>
 #include <linux/virtio_config.h>
 #include <uapi/linux/virtio_mmio.h>
@@ -88,22 +87,8 @@ struct virtio_mmio_device {
 
        void __iomem *base;
        unsigned long version;
-
-       /* a list of queues so we can dispatch IRQs */
-       spinlock_t lock;
-       struct list_head virtqueues;
-};
-
-struct virtio_mmio_vq_info {
-       /* the actual virtqueue */
-       struct virtqueue *vq;
-
-       /* the list node for the virtqueues list */
-       struct list_head node;
 };
 
-
-
 /* Configuration interface */
 
 static u64 vm_get_features(struct virtio_device *vdev)
@@ -300,9 +285,8 @@ static bool vm_notify_with_data(struct virtqueue *vq)
 static irqreturn_t vm_interrupt(int irq, void *opaque)
 {
        struct virtio_mmio_device *vm_dev = opaque;
-       struct virtio_mmio_vq_info *info;
+       struct virtqueue *vq;
        unsigned long status;
-       unsigned long flags;
        irqreturn_t ret = IRQ_NONE;
 
        /* Read and acknowledge interrupts */
@@ -315,10 +299,8 @@ static irqreturn_t vm_interrupt(int irq, void *opaque)
        }
 
        if (likely(status & VIRTIO_MMIO_INT_VRING)) {
-               spin_lock_irqsave(&vm_dev->lock, flags);
-               list_for_each_entry(info, &vm_dev->virtqueues, node)
-                       ret |= vring_interrupt(irq, info->vq);
-               spin_unlock_irqrestore(&vm_dev->lock, flags);
+               virtio_device_for_each_vq(&vm_dev->vdev, vq)
+                       ret |= vring_interrupt(irq, vq);
        }
 
        return ret;
@@ -329,14 +311,8 @@ static irqreturn_t vm_interrupt(int irq, void *opaque)
 static void vm_del_vq(struct virtqueue *vq)
 {
        struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
-       struct virtio_mmio_vq_info *info = vq->priv;
-       unsigned long flags;
        unsigned int index = vq->index;
 
-       spin_lock_irqsave(&vm_dev->lock, flags);
-       list_del(&info->node);
-       spin_unlock_irqrestore(&vm_dev->lock, flags);
-
        /* Select and deactivate the queue */
        writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
        if (vm_dev->version == 1) {
@@ -347,8 +323,6 @@ static void vm_del_vq(struct virtqueue *vq)
        }
 
        vring_del_virtqueue(vq);
-
-       kfree(info);
 }
 
 static void vm_del_vqs(struct virtio_device *vdev)
@@ -375,9 +349,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device 
*vdev, unsigned int in
 {
        struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
        bool (*notify)(struct virtqueue *vq);
-       struct virtio_mmio_vq_info *info;
        struct virtqueue *vq;
-       unsigned long flags;
        unsigned int num;
        int err;
 
@@ -399,13 +371,6 @@ static struct virtqueue *vm_setup_vq(struct virtio_device 
*vdev, unsigned int in
                goto error_available;
        }
 
-       /* Allocate and fill out our active queue description */
-       info = kmalloc(sizeof(*info), GFP_KERNEL);
-       if (!info) {
-               err = -ENOMEM;
-               goto error_kmalloc;
-       }
-
        num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
        if (num == 0) {
                err = -ENOENT;
@@ -463,13 +428,6 @@ static struct virtqueue *vm_setup_vq(struct virtio_device 
*vdev, unsigned int in
                writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
        }
 
-       vq->priv = info;
-       info->vq = vq;
-
-       spin_lock_irqsave(&vm_dev->lock, flags);
-       list_add(&info->node, &vm_dev->virtqueues);
-       spin_unlock_irqrestore(&vm_dev->lock, flags);
-
        return vq;
 
 error_bad_pfn:
@@ -481,8 +439,6 @@ static struct virtqueue *vm_setup_vq(struct virtio_device 
*vdev, unsigned int in
                writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
                WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
        }
-       kfree(info);
-error_kmalloc:
 error_available:
        return ERR_PTR(err);
 }
@@ -627,8 +583,6 @@ static int virtio_mmio_probe(struct platform_device *pdev)
        vm_dev->vdev.dev.release = virtio_mmio_release_dev;
        vm_dev->vdev.config = &virtio_mmio_config_ops;
        vm_dev->pdev = pdev;
-       INIT_LIST_HEAD(&vm_dev->virtqueues);
-       spin_lock_init(&vm_dev->lock);
 
        vm_dev->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(vm_dev->base)) {
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 64cb4b04be7a..8b745ce0cf5f 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -196,7 +196,7 @@ int virtio_device_reset_done(struct virtio_device *dev);
 size_t virtio_max_dma_size(const struct virtio_device *vdev);
 
 #define virtio_device_for_each_vq(vdev, vq) \
-       list_for_each_entry(vq, &vdev->vqs, list)
+       list_for_each_entry(vq, &(vdev)->vqs, list)
 
 /**
  * struct virtio_driver - operations for a virtio I/O driver
-- 
2.31.1.272.g89b43f80a514


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