Linux Virtualization - Dec 2017 - [PATCH v3 0/2] Add cleanup for virtio_mmio driver

this patchset try to add cleanup for virtio_mmio driver, include
virtio_mmio_probe and virtio_mmio_remove

weiping zhang (2):
  virtio_mmio: add cleanup for virtio_mmio_probe
  virtio_mmio: add cleanup for virtio_mmio_remove

 drivers/virtio/virtio_mmio.c | 57 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 47 insertions(+), 10 deletions(-)

-- 
2.9.4

As mentioned at drivers/base/core.c:
/*
 * NOTE: _Never_ directly free @dev after calling this function, even
 * if it returned an error! Always use put_device() to give up the
 * reference initialized in this function instead.
 */
so we don't free vm_dev until vm_dev.dev.release be called.

Signed-off-by: weiping zhang <zhangweiping at didichuxing.com>
---
 drivers/virtio/virtio_mmio.c | 51 +++++++++++++++++++++++++++++++++++---------
 1 file changed, 41 insertions(+), 10 deletions(-)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 74dc717..ec40104 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -493,7 +493,16 @@ static const struct virtio_config_ops
virtio_mmio_config_ops = {
 };
 
 
-static void virtio_mmio_release_dev_empty(struct device *_d) {}
+static void virtio_mmio_release_dev(struct device *_d)
+{
+	struct virtio_device *vdev +			container_of(_d, struct virtio_device, dev);
+	struct virtio_mmio_device *vm_dev +			container_of(vdev, struct
virtio_mmio_device, vdev);
+	struct platform_device *pdev = vm_dev->pdev;
+
+	devm_kfree(&pdev->dev, vm_dev);
+}
 
 /* Platform device */
 
@@ -513,25 +522,30 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 		return -EBUSY;
 
 	vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
-	if (!vm_dev)
-		return  -ENOMEM;
+	if (!vm_dev) {
+		rc = -ENOMEM;
+		goto free_mem;
+	}
 
 	vm_dev->vdev.dev.parent = &pdev->dev;
-	vm_dev->vdev.dev.release = virtio_mmio_release_dev_empty;
+	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_ioremap(&pdev->dev, mem->start,
resource_size(mem));
-	if (vm_dev->base == NULL)
-		return -EFAULT;
+	if (vm_dev->base == NULL) {
+		rc = -EFAULT;
+		goto free_vmdev;
+	}
 
 	/* Check magic value */
 	magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
 	if (magic != ('v' | 'i' << 8 | 'r' << 16 |
't' << 24)) {
 		dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
-		return -ENODEV;
+		rc = -ENODEV;
+		goto unmap;
 	}
 
 	/* Check device version */
@@ -539,7 +553,8 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 	if (vm_dev->version < 1 || vm_dev->version > 2) {
 		dev_err(&pdev->dev, "Version %ld not supported!\n",
 				vm_dev->version);
-		return -ENXIO;
+		rc = -ENXIO;
+		goto unmap;
 	}
 
 	vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
@@ -548,7 +563,8 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 		 * virtio-mmio device with an ID 0 is a (dummy) placeholder
 		 * with no function. End probing now with no error reported.
 		 */
-		return -ENODEV;
+		rc = -ENODEV;
+		goto unmap;
 	}
 	vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
 
@@ -573,7 +589,22 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, vm_dev);
 
-	return register_virtio_device(&vm_dev->vdev);
+	rc = register_virtio_device(&vm_dev->vdev);
+	if (rc) {
+		iounmap(vm_dev->base);
+		devm_release_mem_region(&pdev->dev, mem->start,
+					resource_size(mem));
+		put_device(&vm_dev->vdev.dev);
+	}
+	return rc;
+unmap:
+	iounmap(vm_dev->base);
+free_mem:
+	devm_release_mem_region(&pdev->dev, mem->start,
+			resource_size(mem));
+free_vmdev:
+	devm_kfree(&pdev->dev, vm_dev);
+	return rc;
 }
 
 static int virtio_mmio_remove(struct platform_device *pdev)
-- 
2.9.4

cleanup all resource allocated by virtio_mmio_probe.

Signed-off-by: weiping zhang <zhangweiping at didichuxing.com>
---
 drivers/virtio/virtio_mmio.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index ec40104..a9192fe 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -610,7 +610,13 @@ static int virtio_mmio_probe(struct platform_device *pdev)
 static int virtio_mmio_remove(struct platform_device *pdev)
 {
 	struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
+	struct resource *mem;
 
+	iounmap(vm_dev->base);
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (mem)
+		devm_release_mem_region(&pdev->dev, mem->start,
+			resource_size(mem));
 	unregister_virtio_device(&vm_dev->vdev);
 
 	return 0;
-- 
2.9.4

On Wed, 6 Dec 2017 21:59:16 +0800
weiping zhang <zhangweiping at didichuxing.com> wrote:
> As mentioned at drivers/base/core.c:
> /*
>  * NOTE: _Never_ directly free @dev after calling this function, even
>  * if it returned an error! Always use put_device() to give up the
>  * reference initialized in this function instead.
>  */
> so we don't free vm_dev until vm_dev.dev.release be called.
> 
> Signed-off-by: weiping zhang <zhangweiping at didichuxing.com>
> ---
>  drivers/virtio/virtio_mmio.c | 51
+++++++++++++++++++++++++++++++++++---------
>  1 file changed, 41 insertions(+), 10 deletions(-)
Reviewed-by: Cornelia Huck <cohuck at redhat.com>

On Wed, 6 Dec 2017 21:59:32 +0800
weiping zhang <zhangweiping at didichuxing.com> wrote:
> cleanup all resource allocated by virtio_mmio_probe.
> 
> Signed-off-by: weiping zhang <zhangweiping at didichuxing.com>
> ---
>  drivers/virtio/virtio_mmio.c | 6 ++++++
>  1 file changed, 6 insertions(+)
Reviewed-by: Cornelia Huck <cohuck at redhat.com>