[v2,07/14] vfio/platform: Use open_device() instead of open coding a refcnt scheme

Commit Message

Jason Gunthorpe July 20, 2021, 5:42 p.m. UTC

Platform simply wants to run some code when the device is first
opened/last closed. Use the core framework and locking for this.  Aside
from removing a bit of code this narrows the locking scope from a global
lock.

Signed-off-by: Yishai Hadas <[e-mail]>
Signed-off-by: Jason Gunthorpe <[e-mail]>
---
 drivers/vfio/platform/vfio_platform_common.c  | 79 ++++++++-----------
 drivers/vfio/platform/vfio_platform_private.h |  1 -
 2 files changed, 32 insertions(+), 48 deletions(-)

Comments

Cornelia Huck July 22, 2021, 2:48 p.m. UTC | #1

On Tue, Jul 20 2021, Jason Gunthorpe <[e-mail]> wrote:

> Platform simply wants to run some code when the device is first
> opened/last closed. Use the core framework and locking for this.  Aside
> from removing a bit of code this narrows the locking scope from a global
> lock.
>
> Signed-off-by: Yishai Hadas <[e-mail]>
> Signed-off-by: Jason Gunthorpe <[e-mail]>
> ---
>  drivers/vfio/platform/vfio_platform_common.c  | 79 ++++++++-----------
>  drivers/vfio/platform/vfio_platform_private.h |  1 -
>  2 files changed, 32 insertions(+), 48 deletions(-)

Reviewed-by: Cornelia Huck <[e-mail]>

Jason Gunthorpe July 23, 2021, 12:23 p.m. UTC | #2

On Fri, Jul 23, 2021 at 09:45:21AM +0200, Christoph Hellwig wrote:
> Looks good,
> 
> Reviewed-by: Christoph Hellwig <[e-mail]>
> 
> On Tue, Jul 20, 2021 at 02:42:53PM -0300, Jason Gunthorpe wrote:
> > Platform simply wants to run some code when the device is first
> > opened/last closed. Use the core framework and locking for this.  Aside
> > from removing a bit of code this narrows the locking scope from a global
> > lock.
> > 
> > Signed-off-by: Yishai Hadas <[e-mail]>
> 
> Btw, this seems to miss the second from line for Yishai, which should
> match the first signoff.

Hum, I think we ended up co-developing this on, I can reorder the signed
off's

Jason

Patch

diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
index bdde8605178cd2..6af7ce7d619c25 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -218,65 +218,52 @@  static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
 	return -EINVAL;
 }
 
-static void vfio_platform_release(struct vfio_device *core_vdev)
+static void vfio_platform_close_device(struct vfio_device *core_vdev)
 {
 	struct vfio_platform_device *vdev =
 		container_of(core_vdev, struct vfio_platform_device, vdev);
+	const char *extra_dbg = NULL;
+	int ret;
 
-	mutex_lock(&driver_lock);
-
-	if (!(--vdev->refcnt)) {
-		const char *extra_dbg = NULL;
-		int ret;
-
-		ret = vfio_platform_call_reset(vdev, &extra_dbg);
-		if (ret && vdev->reset_required) {
-			dev_warn(vdev->device, "reset driver is required and reset call failed in release (%d) %s\n",
-				 ret, extra_dbg ? extra_dbg : "");
-			WARN_ON(1);
-		}
-		pm_runtime_put(vdev->device);
-		vfio_platform_regions_cleanup(vdev);
-		vfio_platform_irq_cleanup(vdev);
+	ret = vfio_platform_call_reset(vdev, &extra_dbg);
+	if (WARN_ON(ret && vdev->reset_required)) {
+		dev_warn(
+			vdev->device,
+			"reset driver is required and reset call failed in release (%d) %s\n",
+			ret, extra_dbg ? extra_dbg : "");
 	}
-
-	mutex_unlock(&driver_lock);
+	pm_runtime_put(vdev->device);
+	vfio_platform_regions_cleanup(vdev);
+	vfio_platform_irq_cleanup(vdev);
 }
 
-static int vfio_platform_open(struct vfio_device *core_vdev)
+static int vfio_platform_open_device(struct vfio_device *core_vdev)
 {
 	struct vfio_platform_device *vdev =
 		container_of(core_vdev, struct vfio_platform_device, vdev);
+	const char *extra_dbg = NULL;
 	int ret;
 
-	mutex_lock(&driver_lock);
-
-	if (!vdev->refcnt) {
-		const char *extra_dbg = NULL;
-
-		ret = vfio_platform_regions_init(vdev);
-		if (ret)
-			goto err_reg;
+	ret = vfio_platform_regions_init(vdev);
+	if (ret)
+		return ret;
 
-		ret = vfio_platform_irq_init(vdev);
-		if (ret)
-			goto err_irq;
+	ret = vfio_platform_irq_init(vdev);
+	if (ret)
+		goto err_irq;
 
-		ret = pm_runtime_get_sync(vdev->device);
-		if (ret < 0)
-			goto err_rst;
+	ret = pm_runtime_get_sync(vdev->device);
+	if (ret < 0)
+		goto err_rst;
 
-		ret = vfio_platform_call_reset(vdev, &extra_dbg);
-		if (ret && vdev->reset_required) {
-			dev_warn(vdev->device, "reset driver is required and reset call failed in open (%d) %s\n",
-				 ret, extra_dbg ? extra_dbg : "");
-			goto err_rst;
-		}
+	ret = vfio_platform_call_reset(vdev, &extra_dbg);
+	if (ret && vdev->reset_required) {
+		dev_warn(
+			vdev->device,
+			"reset driver is required and reset call failed in open (%d) %s\n",
+			ret, extra_dbg ? extra_dbg : "");
+		goto err_rst;
 	}
-
-	vdev->refcnt++;
-
-	mutex_unlock(&driver_lock);
 	return 0;
 
 err_rst:
@@ -284,8 +271,6 @@  static int vfio_platform_open(struct vfio_device *core_vdev)
 	vfio_platform_irq_cleanup(vdev);
 err_irq:
 	vfio_platform_regions_cleanup(vdev);
-err_reg:
-	mutex_unlock(&driver_lock);
 	return ret;
 }
 
@@ -616,8 +601,8 @@  static int vfio_platform_mmap(struct vfio_device *core_vdev, struct vm_area_stru
 
 static const struct vfio_device_ops vfio_platform_ops = {
 	.name		= "vfio-platform",
-	.open		= vfio_platform_open,
-	.release	= vfio_platform_release,
+	.open_device	= vfio_platform_open_device,
+	.close_device	= vfio_platform_close_device,
 	.ioctl		= vfio_platform_ioctl,
 	.read		= vfio_platform_read,
 	.write		= vfio_platform_write,
diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
index dfb834c1365946..520d2a8e8375b2 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -48,7 +48,6 @@  struct vfio_platform_device {
 	u32				num_regions;
 	struct vfio_platform_irq	*irqs;
 	u32				num_irqs;
-	int				refcnt;
 	struct mutex			igate;
 	const char			*compat;
 	const char			*acpihid;