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authorThomas Hellstrom <thellstrom@vmware.com>2014-02-25 22:57:44 +0400
committerThomas Hellstrom <thellstrom@vmware.com>2014-03-28 17:19:02 +0400
commitc996fd0b956450563454e7ccc97a82ca31f9d043 (patch)
tree68fa27376f60773bd2feaf5340351cb29e0a834b /include/drm
parenta12cd0025cdc0b4d43b79249dbd8c266af284032 (diff)
downloadlinux-c996fd0b956450563454e7ccc97a82ca31f9d043.tar.xz
drm: Protect the master management with a drm_device::master_mutex v3
The master management was previously protected by the drm_device::struct_mutex. In order to avoid locking order violations in a reworked dropped master security check in the vmwgfx driver, break it out into a separate master_mutex. Locking order is master_mutex -> struct_mutex. Also remove drm_master::blocked since it's not used. v2: Add an inline comment about what drm_device::master_mutex is protecting. v3: Remove unneeded struct_mutex locks. Fix error returns in drm_setmaster_ioctl(). Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Reviewed-by: Brian Paul <brianp@vmware.com> Reviewed-by: David Herrmann <dh.herrmann@gmail.com> Acked-by: Daniel Vetter <daniel@ffwll.ch>
Diffstat (limited to 'include/drm')
-rw-r--r--include/drm/drmP.h46
1 files changed, 25 insertions, 21 deletions
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 3d594ca7fa62..4e24a1a0daeb 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -405,7 +405,8 @@ struct drm_prime_file_private {
struct drm_file {
unsigned always_authenticated :1;
unsigned authenticated :1;
- unsigned is_master :1; /* this file private is a master for a minor */
+ /* Whether we're master for a minor. Protected by master_mutex */
+ unsigned is_master :1;
/* true when the client has asked us to expose stereo 3D mode flags */
unsigned stereo_allowed :1;
@@ -684,28 +685,29 @@ struct drm_gem_object {
#include <drm/drm_crtc.h>
-/* per-master structure */
+/**
+ * struct drm_master - drm master structure
+ *
+ * @refcount: Refcount for this master object.
+ * @minor: Link back to minor char device we are master for. Immutable.
+ * @unique: Unique identifier: e.g. busid. Protected by drm_global_mutex.
+ * @unique_len: Length of unique field. Protected by drm_global_mutex.
+ * @unique_size: Amount allocated. Protected by drm_global_mutex.
+ * @magiclist: Hash of used authentication tokens. Protected by struct_mutex.
+ * @magicfree: List of used authentication tokens. Protected by struct_mutex.
+ * @lock: DRI lock information.
+ * @driver_priv: Pointer to driver-private information.
+ */
struct drm_master {
-
- struct kref refcount; /* refcount for this master */
-
- struct drm_minor *minor; /**< link back to minor we are a master for */
-
- char *unique; /**< Unique identifier: e.g., busid */
- int unique_len; /**< Length of unique field */
- int unique_size; /**< amount allocated */
-
- int blocked; /**< Blocked due to VC switch? */
-
- /** \name Authentication */
- /*@{ */
+ struct kref refcount;
+ struct drm_minor *minor;
+ char *unique;
+ int unique_len;
+ int unique_size;
struct drm_open_hash magiclist;
struct list_head magicfree;
- /*@} */
-
- struct drm_lock_data lock; /**< Information on hardware lock */
-
- void *driver_priv; /**< Private structure for driver to use */
+ struct drm_lock_data lock;
+ void *driver_priv;
};
/* Size of ringbuffer for vblank timestamps. Just double-buffer
@@ -1020,7 +1022,8 @@ struct drm_minor {
struct list_head debugfs_list;
struct mutex debugfs_lock; /* Protects debugfs_list. */
- struct drm_master *master; /* currently active master for this node */
+ /* currently active master for this node. Protected by master_mutex */
+ struct drm_master *master;
struct drm_mode_group mode_group;
};
@@ -1070,6 +1073,7 @@ struct drm_device {
/*@{ */
spinlock_t count_lock; /**< For inuse, drm_device::open_count, drm_device::buf_use */
struct mutex struct_mutex; /**< For others */
+ struct mutex master_mutex; /**< For drm_minor::master and drm_file::is_master */
/*@} */
/** \name Usage Counters */