[PATCH v4 3/4] virtio_vop: don't kfree device on register failure

[weiping zhang]

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 vdev until vdev->vdev.dev.release be called.

Signed-off-by: weiping zhang <zhangweip...@didichuxing.com>
---
 drivers/misc/mic/vop/vop_main.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/mic/vop/vop_main.c b/drivers/misc/mic/vop/vop_main.c
index a341938..3633202 100644
--- a/drivers/misc/mic/vop/vop_main.c
+++ b/drivers/misc/mic/vop/vop_main.c
@@ -452,10 +452,12 @@ static irqreturn_t vop_virtio_intr_handler(int irq, void 
*data)
 
 static void vop_virtio_release_dev(struct device *_d)
 {
-       /*
-        * No need for a release method similar to virtio PCI.
-        * Provide an empty one to avoid getting a warning from core.
-        */
+       struct virtio_device *vdev =
+                       container_of(_d, struct virtio_device, dev);
+       struct _vop_vdev *vop_vdev =
+                       container_of(vdev, struct _vop_vdev, vdev);
+
+       kfree(vop_vdev);
 }
 
 /*
@@ -466,7 +468,7 @@ static int _vop_add_device(struct mic_device_desc __iomem 
*d,
                           unsigned int offset, struct vop_device *vpdev,
                           int dnode)
 {
-       struct _vop_vdev *vdev;
+       struct _vop_vdev *vdev, *reg_dev = NULL;
        int ret;
        u8 type = ioread8(&d->type);
 
@@ -497,6 +499,7 @@ static int _vop_add_device(struct mic_device_desc __iomem 
*d,
        vdev->c2h_vdev_db = ioread8(&vdev->dc->c2h_vdev_db);
 
        ret = register_virtio_device(&vdev->vdev);
+       reg_dev = vdev;
        if (ret) {
                dev_err(_vop_dev(vdev),
                        "Failed to register vop device %u type %u\n",
@@ -512,7 +515,10 @@ static int _vop_add_device(struct mic_device_desc __iomem 
*d,
 free_irq:
        vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
 kfree:
-       kfree(vdev);
+       if (reg_dev)
+               put_device(&vdev->vdev.dev);
+       else
+               kfree(vdev);
        return ret;
 }
 
@@ -568,7 +574,7 @@ static int _vop_remove_device(struct mic_device_desc 
__iomem *d,
                iowrite8(-1, &dc->h2c_vdev_db);
                if (status & VIRTIO_CONFIG_S_DRIVER_OK)
                        wait_for_completion(&vdev->reset_done);
-               kfree(vdev);
+               put_device(&vdev->vdev.dev);
                iowrite8(1, &dc->guest_ack);
                dev_dbg(&vpdev->dev, "%s %d guest_ack %d\n",
                        __func__, __LINE__, ioread8(&dc->guest_ack));
-- 
2.9.4

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