wifi: mt76: Use IS_ERR() check for mt76_register_debugfs_fops()

[PATCH] wifi: mt76: Use IS_ERR() check for mt76_register_debugfs_fops()

Posted by Ingyu Jang 4 weeks ago

mt76_register_debugfs_fops() returns the dentry from
debugfs_create_dir(), which yields an error pointer on failure and
never NULL. The NULL checks in the per-chip *_init_debugfs() helpers
are therefore unreachable, and on a real failure the ERR_PTR would
be returned to callers as a valid pointer.

Use IS_ERR() and propagate the actual error via PTR_ERR() in
mt7615/mt7915/mt7921/mt7925/mt7996.

Signed-off-by: Ingyu Jang <ingyujang25@korea.ac.kr>
---
 drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c | 4 ++--
 drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c | 4 ++--
 drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c | 4 ++--
 drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c | 4 ++--
 drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c | 4 ++--
 5 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c
index 0f7b20152279c..5c3646a67e4b7 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c
@@ -550,8 +550,8 @@ int mt7615_init_debugfs(struct mt7615_dev *dev)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(&dev->mphy, &fops_regval);
-	if (!dir)
-		return -ENOMEM;
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
 
 	if (is_mt7615(&dev->mt76))
 		debugfs_create_devm_seqfile(dev->mt76.dev, "xmit-queues", dir,
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c
index 26ed3745af43e..f62a17c8958ac 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c
@@ -1296,8 +1296,8 @@ int mt7915_init_debugfs(struct mt7915_phy *phy)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(phy->mt76, NULL);
-	if (!dir)
-		return -ENOMEM;
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
 	debugfs_create_file("muru_debug", 0600, dir, dev, &fops_muru_debug);
 	debugfs_create_file("muru_stats", 0400, dir, phy,
 			    &mt7915_muru_stats_fops);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c
index 4333005b3ad95..4da339867b6a7 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c
@@ -266,8 +266,8 @@ int mt7921_init_debugfs(struct mt792x_dev *dev)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(&dev->mphy, &fops_regval);
-	if (!dir)
-		return -ENOMEM;
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
 
 	if (mt76_is_mmio(&dev->mt76))
 		debugfs_create_devm_seqfile(dev->mt76.dev, "xmit-queues",
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c
index e2498659c884e..01aa4a1071fdd 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c
@@ -291,8 +291,8 @@ int mt7925_init_debugfs(struct mt792x_dev *dev)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(&dev->mphy, &fops_regval);
-	if (!dir)
-		return -ENOMEM;
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
 
 	if (mt76_is_mmio(&dev->mt76))
 		debugfs_create_devm_seqfile(dev->mt76.dev, "xmit-queues",
diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c
index 34af800964d11..63cd490977106 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c
@@ -875,8 +875,8 @@ int mt7996_init_debugfs(struct mt7996_dev *dev)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(&dev->mphy, NULL);
-	if (!dir)
-		return -ENOMEM;
+	if (IS_ERR(dir))
+		return PTR_ERR(dir);
 
 	debugfs_create_file("hw-queues", 0400, dir, dev,
 			    &mt7996_hw_queues_fops);
-- 
2.34.1

[PATCH] wifi: mt76: Drop unneeded mt76_register_debugfs_fops() return checks

Posted by Ingyu Jang 3 weeks, 3 days ago

mt76_register_debugfs_fops() returns the dentry from
debugfs_create_dir(), which yields an error pointer on failure
(notably ERR_PTR(-ENODEV) when CONFIG_DEBUG_FS=n), never NULL. Per
commit ff9fb72bc077 ("debugfs: return error values, not NULL"),
callers do not need to check the return value.

Drop the dead !dir checks in mt7615/mt7915/mt7921/mt7925/mt7996
_init_debugfs(). Converting them to IS_ERR() instead would have
exposed a probe abort on CONFIG_DEBUG_FS=n, since each
*_init_debugfs() caller propagates the helper's return value.

This patch supersedes an earlier proposal that converted the checks
to IS_ERR().

Link: https://lore.kernel.org/all/20260514193243.2518979-1-ingyujang25@korea.ac.kr
Signed-off-by: Ingyu Jang <ingyujang25@korea.ac.kr>
---

 drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c | 2 --
 drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c | 3 +--
 drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c | 2 --
 drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c | 2 --
 drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c | 2 --
 5 files changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c
index 0f7b20152279c..6a1475e3c8999 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7615/debugfs.c
@@ -550,8 +550,6 @@ int mt7615_init_debugfs(struct mt7615_dev *dev)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(&dev->mphy, &fops_regval);
-	if (!dir)
-		return -ENOMEM;
 
 	if (is_mt7615(&dev->mt76))
 		debugfs_create_devm_seqfile(dev->mt76.dev, "xmit-queues", dir,
diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c
index 26ed3745af43e..4d0854fe785bd 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/debugfs.c
@@ -1296,8 +1296,7 @@ int mt7915_init_debugfs(struct mt7915_phy *phy)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(phy->mt76, NULL);
-	if (!dir)
-		return -ENOMEM;
+
 	debugfs_create_file("muru_debug", 0600, dir, dev, &fops_muru_debug);
 	debugfs_create_file("muru_stats", 0400, dir, phy,
 			    &mt7915_muru_stats_fops);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c
index 4333005b3ad95..a5a70d8e8544a 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c
@@ -266,8 +266,6 @@ int mt7921_init_debugfs(struct mt792x_dev *dev)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(&dev->mphy, &fops_regval);
-	if (!dir)
-		return -ENOMEM;
 
 	if (mt76_is_mmio(&dev->mt76))
 		debugfs_create_devm_seqfile(dev->mt76.dev, "xmit-queues",
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c
index e2498659c884e..d01ff49de47af 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/debugfs.c
@@ -291,8 +291,6 @@ int mt7925_init_debugfs(struct mt792x_dev *dev)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(&dev->mphy, &fops_regval);
-	if (!dir)
-		return -ENOMEM;
 
 	if (mt76_is_mmio(&dev->mt76))
 		debugfs_create_devm_seqfile(dev->mt76.dev, "xmit-queues",
diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c
index 76d623b2cafb4..327fc2032c8da 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/debugfs.c
@@ -856,8 +856,6 @@ int mt7996_init_debugfs(struct mt7996_dev *dev)
 	struct dentry *dir;
 
 	dir = mt76_register_debugfs_fops(&dev->mphy, NULL);
-	if (!dir)
-		return -ENOMEM;
 
 	debugfs_create_file("hw-queues", 0400, dir, dev,
 			    &mt7996_hw_queues_fops);
-- 
2.34.1