drm: Protect dev->filelist with its own mutex
amdgpu gained dev->struct_mutex usage, and that's because it's walking
the dev->filelist list. Protect that list with it's own lock to take
one more step towards getting rid of struct_mutex usage in drivers
once and for all.
While doing the conversion I noticed that 2 debugfs files in i915
completely lacked appropriate locking. Fix that up too.
v2: don't forget to switch to drm_gem_object_unreference_unlocked.
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461691808-12414-9-git-send-email-daniel.vetter@ffwll.ch
diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index c3d0aaa..7af7f8b 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -297,9 +297,9 @@
}
mutex_unlock(&dev->master_mutex);
- mutex_lock(&dev->struct_mutex);
+ mutex_lock(&dev->filelist_mutex);
list_add(&priv->lhead, &dev->filelist);
- mutex_unlock(&dev->struct_mutex);
+ mutex_unlock(&dev->filelist_mutex);
#ifdef __alpha__
/*
@@ -447,8 +447,11 @@
DRM_DEBUG("open_count = %d\n", dev->open_count);
- mutex_lock(&dev->struct_mutex);
+ mutex_lock(&dev->filelist_mutex);
list_del(&file_priv->lhead);
+ mutex_unlock(&dev->filelist_mutex);
+
+ mutex_lock(&dev->struct_mutex);
if (file_priv->magic)
idr_remove(&file_priv->master->magic_map, file_priv->magic);
mutex_unlock(&dev->struct_mutex);