No one looks at the major/minor versions except the unique/busid stuff. If we protect that with the master_mutex (since it also affects the unique of each master, oh well) we can mark these two IOCTL with DRM_UNLOCKED.
While doing this I realized that the comment for the magic_map is outdated, I've forgotten to update it in:
commit d2b34ee62b409a03c6fe43c07b779983be51d017 Author: Daniel Vetter daniel.vetter@ffwll.ch Date: Fri Jun 17 09:33:21 2016 +0200
drm: Protect authmagic with master_mutex
Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Emil Velikov emil.l.velikov@gmail.com Signed-off-by: Daniel Vetter daniel.vetter@intel.com --- drivers/gpu/drm/drm_ioctl.c | 12 +++++++++--- include/drm/drm_auth.h | 17 +++++++++++++---- 2 files changed, 22 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 17e941a533bd..42a17ea5d801 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -115,11 +115,15 @@ static int drm_getunique(struct drm_device *dev, void *data, struct drm_unique *u = data; struct drm_master *master = file_priv->master;
+ mutex_lock(&master->dev->master_mutex); if (u->unique_len >= master->unique_len) { - if (copy_to_user(u->unique, master->unique, master->unique_len)) + if (copy_to_user(u->unique, master->unique, master->unique_len)) { + mutex_unlock(&master->dev->master_mutex); return -EFAULT; + } } u->unique_len = master->unique_len; + mutex_unlock(&master->dev->master_mutex);
return 0; } @@ -340,6 +344,7 @@ static int drm_setversion(struct drm_device *dev, void *data, struct drm_file *f struct drm_set_version *sv = data; int if_version, retcode = 0;
+ mutex_lock(&dev->master_mutex); if (sv->drm_di_major != -1) { if (sv->drm_di_major != DRM_IF_MAJOR || sv->drm_di_minor < 0 || sv->drm_di_minor > DRM_IF_MINOR) { @@ -374,6 +379,7 @@ static int drm_setversion(struct drm_device *dev, void *data, struct drm_file *f sv->drm_di_minor = DRM_IF_MINOR; sv->drm_dd_major = dev->driver->major; sv->drm_dd_minor = dev->driver->minor; + mutex_unlock(&dev->master_mutex);
return retcode; } @@ -528,7 +534,7 @@ EXPORT_SYMBOL(drm_ioctl_permit); static const struct drm_ioctl_desc drm_ioctls[] = { DRM_IOCTL_DEF(DRM_IOCTL_VERSION, drm_version, DRM_UNLOCKED|DRM_RENDER_ALLOW|DRM_CONTROL_ALLOW), - DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, 0), + DRM_IOCTL_DEF(DRM_IOCTL_GET_UNIQUE, drm_getunique, DRM_UNLOCKED), DRM_IOCTL_DEF(DRM_IOCTL_GET_MAGIC, drm_getmagic, DRM_UNLOCKED), DRM_IOCTL_DEF(DRM_IOCTL_IRQ_BUSID, drm_irq_by_busid, DRM_MASTER|DRM_ROOT_ONLY), DRM_IOCTL_DEF(DRM_IOCTL_GET_MAP, drm_legacy_getmap_ioctl, DRM_UNLOCKED), @@ -536,7 +542,7 @@ static const struct drm_ioctl_desc drm_ioctls[] = { DRM_IOCTL_DEF(DRM_IOCTL_GET_STATS, drm_getstats, DRM_UNLOCKED), DRM_IOCTL_DEF(DRM_IOCTL_GET_CAP, drm_getcap, DRM_UNLOCKED|DRM_RENDER_ALLOW), DRM_IOCTL_DEF(DRM_IOCTL_SET_CLIENT_CAP, drm_setclientcap, 0), - DRM_IOCTL_DEF(DRM_IOCTL_SET_VERSION, drm_setversion, DRM_MASTER), + DRM_IOCTL_DEF(DRM_IOCTL_SET_VERSION, drm_setversion, DRM_UNLOCKED | DRM_MASTER),
DRM_IOCTL_DEF(DRM_IOCTL_SET_UNIQUE, drm_invalid_op, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY), DRM_IOCTL_DEF(DRM_IOCTL_BLOCK, drm_noop, DRM_AUTH|DRM_MASTER|DRM_ROOT_ONLY), diff --git a/include/drm/drm_auth.h b/include/drm/drm_auth.h index 610223b0481b..155588eb8ccf 100644 --- a/include/drm/drm_auth.h +++ b/include/drm/drm_auth.h @@ -33,10 +33,7 @@ * * @refcount: Refcount for this master object. * @dev: Link back to the DRM device - * @unique: Unique identifier: e.g. busid. Protected by drm_global_mutex. - * @unique_len: Length of unique field. Protected by drm_global_mutex. - * @magic_map: Map of used authentication tokens. Protected by struct_mutex. - * @lock: DRI lock information. + * @lock: DRI1 lock information. * @driver_priv: Pointer to driver-private information. * * Note that master structures are only relevant for the legacy/primary device @@ -45,8 +42,20 @@ struct drm_master { struct kref refcount; struct drm_device *dev; + /** + * @unique: Unique identifier: e.g. busid. Protected by struct + * &drm_device master_mutex. + */ char *unique; + /** + * @unique_len: Length of unique field. Protected by struct &drm_device + * master_mutex. + */ int unique_len; + /** + * @magic_map: Map of used authentication tokens. Protected by struct + * &drm_device master_mutex. + */ struct idr magic_map; struct drm_lock_data lock; void *driver_priv;