[3/3] ASoC: Don't try to register debugfs entries if the parent does not exist

Commit Message

Lars-Peter Clausen April 9, 2015, 8:52 a.m. UTC

If the registration of a debugfs directory fails this is treated as a
non-fatal error in ASoC and operation continues as normal. This means we
need to be careful and check if the parent debugfs directory exists if we
try to register a debugfs file or sub-directory. Otherwise we might end up
passing NULL for the parent and the file or directory will be registered in
the top-level debugfs directory.

Signed-off-by: Lars-Peter Clausen <[e-mail]>
---
 sound/soc/soc-core.c | 66 +++++++++++++++++++++++++++++++++++-----------------
 sound/soc/soc-dapm.c |  3 +++
 sound/soc/soc-pcm.c  |  8 +++++--
 3 files changed, 54 insertions(+), 23 deletions(-)

Comments

Mark Brown April 9, 2015, 11:24 a.m. UTC | #1

On Thu, Apr 09, 2015 at 10:52:38AM +0200, Lars-Peter Clausen wrote:
> If the registration of a debugfs directory fails this is treated as a
> non-fatal error in ASoC and operation continues as normal. This means we
> need to be careful and check if the parent debugfs directory exists if we
> try to register a debugfs file or sub-directory. Otherwise we might end up
> passing NULL for the parent and the file or directory will be registered in
> the top-level debugfs directory.

Hrm, right.  On the one hand just silently ignoring the knock on errors
feels icky on the other hand it's probably better to do something like
this providing the earlier errors got reported (and were actually
earlier, I can see us reordering things and causing further problems
later on).

Patch

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index e97b395..32ebe5b 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -292,6 +292,9 @@  static const struct file_operations codec_reg_fops = {
 
 static void soc_init_component_debugfs(struct snd_soc_component *component)
 {
+	if (!component->card->debugfs_card_root)
+		return;
+
 	if (component->debugfs_prefix) {
 		char *name;
 
@@ -455,6 +458,9 @@  static const struct file_operations platform_list_fops = {
 
 static void soc_init_card_debugfs(struct snd_soc_card *card)
 {
+	if (!snd_soc_debugfs_root)
+		return;
+
 	card->debugfs_card_root = debugfs_create_dir(card->name,
 						     snd_soc_debugfs_root);
 	if (!card->debugfs_card_root) {
@@ -476,6 +482,34 @@  static void soc_cleanup_card_debugfs(struct snd_soc_card *card)
 	debugfs_remove_recursive(card->debugfs_card_root);
 }
 
+
+static void snd_soc_debugfs_init(void)
+{
+	snd_soc_debugfs_root = debugfs_create_dir("asoc", NULL);
+	if (IS_ERR(snd_soc_debugfs_root) || !snd_soc_debugfs_root) {
+		pr_warn("ASoC: Failed to create debugfs directory\n");
+		snd_soc_debugfs_root = NULL;
+		return;
+	}
+
+	if (!debugfs_create_file("codecs", 0444, snd_soc_debugfs_root, NULL,
+				 &codec_list_fops))
+		pr_warn("ASoC: Failed to create CODEC list debugfs file\n");
+
+	if (!debugfs_create_file("dais", 0444, snd_soc_debugfs_root, NULL,
+				 &dai_list_fops))
+		pr_warn("ASoC: Failed to create DAI list debugfs file\n");
+
+	if (!debugfs_create_file("platforms", 0444, snd_soc_debugfs_root, NULL,
+				 &platform_list_fops))
+		pr_warn("ASoC: Failed to create platform list debugfs file\n");
+}
+
+static void snd_soc_debugfs_exit(void)
+{
+	debugfs_remove_recursive(snd_soc_debugfs_root);
+}
+
 #else
 
 #define soc_init_codec_debugfs NULL
@@ -497,6 +531,15 @@  static inline void soc_init_card_debugfs(struct snd_soc_card *card)
 static inline void soc_cleanup_card_debugfs(struct snd_soc_card *card)
 {
 }
+
+static inline void snd_soc_debugfs_init(void)
+{
+}
+
+static inline void snd_soc_debugfs_exit(void)
+{
+}
+
 #endif
 
 struct snd_pcm_substream *snd_soc_get_dai_substream(struct snd_soc_card *card,
@@ -3584,26 +3627,7 @@  EXPORT_SYMBOL_GPL(snd_soc_of_get_dai_link_codecs);
 
 static int __init snd_soc_init(void)
 {
-#ifdef CONFIG_DEBUG_FS
-	snd_soc_debugfs_root = debugfs_create_dir("asoc", NULL);
-	if (IS_ERR(snd_soc_debugfs_root) || !snd_soc_debugfs_root) {
-		pr_warn("ASoC: Failed to create debugfs directory\n");
-		snd_soc_debugfs_root = NULL;
-	}
-
-	if (!debugfs_create_file("codecs", 0444, snd_soc_debugfs_root, NULL,
-				 &codec_list_fops))
-		pr_warn("ASoC: Failed to create CODEC list debugfs file\n");
-
-	if (!debugfs_create_file("dais", 0444, snd_soc_debugfs_root, NULL,
-				 &dai_list_fops))
-		pr_warn("ASoC: Failed to create DAI list debugfs file\n");
-
-	if (!debugfs_create_file("platforms", 0444, snd_soc_debugfs_root, NULL,
-				 &platform_list_fops))
-		pr_warn("ASoC: Failed to create platform list debugfs file\n");
-#endif
-
+	snd_soc_debugfs_init();
 	snd_soc_util_init();
 
 	return platform_driver_register(&soc_driver);
@@ -3613,9 +3637,9 @@  module_init(snd_soc_init);
 static void __exit snd_soc_exit(void)
 {
 	snd_soc_util_exit();
+	snd_soc_debugfs_exit();
 
 #ifdef CONFIG_DEBUG_FS
-	debugfs_remove_recursive(snd_soc_debugfs_root);
 #endif
 	platform_driver_unregister(&soc_driver);
 }
diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 4bd2a6f..defe0f0 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -1918,6 +1918,9 @@  void snd_soc_dapm_debugfs_init(struct snd_soc_dapm_context *dapm,
 {
 	struct dentry *d;
 
+	if (!parent)
+		return;
+
 	dapm->debugfs_dapm = debugfs_create_dir("dapm", parent);
 
 	if (!dapm->debugfs_dapm) {
diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index e67378a..35fe58f4 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1097,8 +1097,9 @@  static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 			stream ? "<-" : "->", be->dai_link->name);
 
 #ifdef CONFIG_DEBUG_FS
-	dpcm->debugfs_state = debugfs_create_u32(be->dai_link->name, 0644,
-			fe->debugfs_dpcm_root, &dpcm->state);
+	if (fe->debugfs_dpcm_root)
+		dpcm->debugfs_state = debugfs_create_u32(be->dai_link->name, 0644,
+				fe->debugfs_dpcm_root, &dpcm->state);
 #endif
 	return 1;
 }
@@ -2808,6 +2809,9 @@  void soc_dpcm_debugfs_add(struct snd_soc_pcm_runtime *rtd)
 	if (!rtd->dai_link)
 		return;
 
+	if (!rtd->card->debugfs_card_root)
+		return;
+
 	rtd->debugfs_dpcm_root = debugfs_create_dir(rtd->dai_link->name,
 			rtd->card->debugfs_card_root);
 	if (!rtd->debugfs_dpcm_root) {