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drm: add minor-lookup/release helpers

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Instead of accessing drm_minors_idr directly, this adds a small helper to
hide the internals. This will help us later to remove the drm_global_mutex
requirement for minor-lookup.

Furthermore, this also makes sure that minor->dev is always valid and
takes a reference-count to the device as long as the minor is used in an
open-file. This way, "struct file*"->private_data->dev is guaranteed to be
valid (which it has to, as we cannot reset it).

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
David Herrmann
2014-01-29 10:49:19 +01:00
parent 099d1c290e
commit 1616c525b9
3 changed files with 70 additions and 23 deletions
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50
drivers/gpu/drm/drm_fops.c
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@@ -79,23 +79,22 @@ static int drm_setup(struct drm_device * dev)
*/
int drm_open(struct inode *inode, struct file *filp)
{
struct drm_device *dev = NULL;
int minor_id = iminor(inode);
struct drm_device *dev;
struct drm_minor *minor;
int retcode = 0;
int retcode;
int need_setup = 0;
struct address_space *old_mapping;
struct address_space *old_imapping;
minor = idr_find(&drm_minors_idr, minor_id);
if (!minor)
return -ENODEV;
minor = drm_minor_acquire(iminor(inode));
if (IS_ERR(minor))
return PTR_ERR(minor);
if (!(dev = minor->dev))
return -ENODEV;
if (drm_device_is_unplugged(dev))
return -ENODEV;
dev = minor->dev;
if (drm_device_is_unplugged(dev)) {
retcode = -ENODEV;
goto err_release;
}
if (!dev->open_count++)
need_setup = 1;
@@ -128,6 +127,8 @@ err_undo:
dev->dev_mapping = old_mapping;
mutex_unlock(&dev->struct_mutex);
dev->open_count--;
err_release:
drm_minor_release(minor);
return retcode;
}
EXPORT_SYMBOL(drm_open);
@@ -143,33 +144,33 @@ EXPORT_SYMBOL(drm_open);
*/
int drm_stub_open(struct inode *inode, struct file *filp)
{
struct drm_device *dev = NULL;
struct drm_device *dev;
struct drm_minor *minor;
int minor_id = iminor(inode);
int err = -ENODEV;
const struct file_operations *new_fops;
DRM_DEBUG("\n");
mutex_lock(&drm_global_mutex);
minor = idr_find(&drm_minors_idr, minor_id);
if (!minor)
goto out;
if (!(dev = minor->dev))
goto out;
minor = drm_minor_acquire(iminor(inode));
if (IS_ERR(minor))
goto out_unlock;
dev = minor->dev;
if (drm_device_is_unplugged(dev))
goto out;
goto out_release;
new_fops = fops_get(dev->driver->fops);
if (!new_fops)
goto out;
goto out_release;
replace_fops(filp, new_fops);
if (filp->f_op->open)
err = filp->f_op->open(inode, filp);
out:
out_release:
drm_minor_release(minor);
out_unlock:
mutex_unlock(&drm_global_mutex);
return err;
}
@@ -453,7 +454,8 @@ int drm_lastclose(struct drm_device * dev)
int drm_release(struct inode *inode, struct file *filp)
{
struct drm_file *file_priv = filp->private_data;
struct drm_device *dev = file_priv->minor->dev;
struct drm_minor *minor = file_priv->minor;
struct drm_device *dev = minor->dev;
int retcode = 0;
mutex_lock(&drm_global_mutex);
@@ -575,6 +577,8 @@ int drm_release(struct inode *inode, struct file *filp)
}
mutex_unlock(&drm_global_mutex);
drm_minor_release(minor);
return retcode;
}
EXPORT_SYMBOL(drm_release);