diff options
author | David Herrmann <dh.herrmann@gmail.com> | 2014-01-03 14:24:19 +0100 |
---|---|---|
committer | David Herrmann <dh.herrmann@gmail.com> | 2014-03-16 12:23:33 +0100 |
commit | 6796cb16c088905bf3af40548fda68c09e6f6ee5 (patch) | |
tree | d40162f17dad7b54ac63feaf62b7c84493556f5a /drivers/gpu/drm/drm_fops.c | |
parent | 31bbe16f6d88622d6731fa2cb4ab38d57d844ac1 (diff) |
drm: use anon-inode instead of relying on cdevs
DRM drivers share a common address_space across all character-devices of a
single DRM device. This allows simple buffer eviction and mapping-control.
However, DRM core currently waits for the first ->open() on any char-dev
to mark the underlying inode as backing inode of the device. This delayed
initialization causes ugly conditions all over the place:
if (dev->dev_mapping)
do_sth();
To avoid delayed initialization and to stop reusing the inode of the
char-dev, we allocate an anonymous inode for each DRM device and reset
filp->f_mapping to it on ->open().
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Diffstat (limited to 'drivers/gpu/drm/drm_fops.c')
-rw-r--r-- | drivers/gpu/drm/drm_fops.c | 25 |
1 files changed, 3 insertions, 22 deletions
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c index 7f2af9aca038..147a84d9da9b 100644 --- a/drivers/gpu/drm/drm_fops.c +++ b/drivers/gpu/drm/drm_fops.c @@ -84,8 +84,6 @@ int drm_open(struct inode *inode, struct file *filp) struct drm_minor *minor; int retcode = 0; int need_setup = 0; - struct address_space *old_mapping; - struct address_space *old_imapping; minor = idr_find(&drm_minors_idr, minor_id); if (!minor) @@ -99,16 +97,9 @@ int drm_open(struct inode *inode, struct file *filp) if (!dev->open_count++) need_setup = 1; - mutex_lock(&dev->struct_mutex); - old_imapping = inode->i_mapping; - old_mapping = dev->dev_mapping; - if (old_mapping == NULL) - dev->dev_mapping = &inode->i_data; - /* ihold ensures nobody can remove inode with our i_data */ - ihold(container_of(dev->dev_mapping, struct inode, i_data)); - inode->i_mapping = dev->dev_mapping; - filp->f_mapping = dev->dev_mapping; - mutex_unlock(&dev->struct_mutex); + + /* share address_space across all char-devs of a single device */ + filp->f_mapping = dev->anon_inode->i_mapping; retcode = drm_open_helper(inode, filp, dev); if (retcode) @@ -121,12 +112,6 @@ int drm_open(struct inode *inode, struct file *filp) return 0; err_undo: - mutex_lock(&dev->struct_mutex); - filp->f_mapping = old_imapping; - inode->i_mapping = old_imapping; - iput(container_of(dev->dev_mapping, struct inode, i_data)); - dev->dev_mapping = old_mapping; - mutex_unlock(&dev->struct_mutex); dev->open_count--; return retcode; } @@ -434,7 +419,6 @@ int drm_lastclose(struct drm_device * dev) drm_legacy_dma_takedown(dev); - dev->dev_mapping = NULL; mutex_unlock(&dev->struct_mutex); drm_legacy_dev_reinit(dev); @@ -549,9 +533,6 @@ int drm_release(struct inode *inode, struct file *filp) } } - BUG_ON(dev->dev_mapping == NULL); - iput(container_of(dev->dev_mapping, struct inode, i_data)); - /* drop the reference held my the file priv */ if (file_priv->master) drm_master_put(&file_priv->master); |