drm/nouveau: Do not fail module init on debugfs errors

If CONFIG_DEBUG_FS is enabled, nouveau_drm_init() returns an error if it
fails to create the "nouveau" directory in debugfs. One case where that
will happen is when debugfs access is restricted by
CONFIG_DEBUG_FS_ALLOW_NONE or by the boot parameter debugfs=off, which
cause the debugfs APIs to return -EPERM.

So just ignore errors from debugfs. Note that nouveau_debugfs_root may
be an error now, but that is a standard pattern for debugfs. From
include/linux/debugfs.h:

"NOTE: it's expected that most callers should _ignore_ the errors
returned by this function. Other debugfs functions handle the fact that
the "dentry" passed to them could be an error and they don't crash in
that case. Drivers should generally work fine even if debugfs fails to
init anyway."

Fixes: 97118a1816d2 ("drm/nouveau: create module debugfs root")
Cc: stable@vger.kernel.org
Signed-off-by: Aaron Thompson <dev@aaront.org>
Acked-by: Timur Tabi <ttabi@nvidia.com>
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20250703211949.9916-1-dev@aaront.org

diff --git a/drivers/gpu/drm/nouveau/nouveau_debugfs.c b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
index 200e65a7cefc4ec19e0be7eb3a51bfa5847bd0c3..c7869a639befce75aa5200cae0928d073d079c33 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_debugfs.c
+++ b/drivers/gpu/drm/nouveau/nouveau_debugfs.c
@@ -314,14 +314,10 @@ nouveau_debugfs_fini(struct nouveau_drm *drm)
        drm->debugfs = NULL;
 }
 
-int
+void
 nouveau_module_debugfs_init(void)
 {
        nouveau_debugfs_root = debugfs_create_dir("nouveau", NULL);
-       if (IS_ERR(nouveau_debugfs_root))
-               return PTR_ERR(nouveau_debugfs_root);
-
-       return 0;
 }
 
 void

diff --git a/drivers/gpu/drm/nouveau/nouveau_debugfs.h b/drivers/gpu/drm/nouveau/nouveau_debugfs.h
index b7617b344ee26dbe5ea3724ba3bb6091c606bd1d..d05ed0e641c4aa66bc2b1fb850ae6ee82662c0a1 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_debugfs.h
+++ b/drivers/gpu/drm/nouveau/nouveau_debugfs.h
@@ -24,7 +24,7 @@ extern void nouveau_debugfs_fini(struct nouveau_drm *);
 
 extern struct dentry *nouveau_debugfs_root;
 
-int  nouveau_module_debugfs_init(void);
+void nouveau_module_debugfs_init(void);
 void nouveau_module_debugfs_fini(void);
 #else
 static inline void
@@ -42,10 +42,9 @@ nouveau_debugfs_fini(struct nouveau_drm *drm)
 {
 }
 
-static inline int
+static inline void
 nouveau_module_debugfs_init(void)
 {
-       return 0;
 }
 
 static inline void

diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 0c82a63cd49d3ee463f8630183a271b4348a62bc..1527b801f013aacf82af96382c4be9320a595d50 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -1461,9 +1461,7 @@ nouveau_drm_init(void)
        if (!nouveau_modeset)
                return 0;
 
-       ret = nouveau_module_debugfs_init();
-       if (ret)
-               return ret;
+       nouveau_module_debugfs_init();
 
 #ifdef CONFIG_NOUVEAU_PLATFORM_DRIVER
        platform_driver_register(&nouveau_platform_driver);