[PATCH] msm: no need to check return value of debugfs_create functions

[PATCH] msm: no need to check return value of debugfs_create functions

[Greg Kroah-Hartman]

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: linux-arm-msm@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: freedreno@lists.freedesktop.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/msm/msm_perf.c | 15 ++-------------
 drivers/gpu/drm/msm/msm_rd.c   | 15 ++-------------
 2 files changed, 4 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_perf.c b/drivers/gpu/drm/msm/msm_perf.c
index 5ab21bd2decb..95948cfe7a12 100644
--- a/drivers/gpu/drm/msm/msm_perf.c
+++ b/drivers/gpu/drm/msm/msm_perf.c
@@ -205,7 +205,6 @@ int msm_perf_debugfs_init(struct drm_minor *minor)
 {
 	struct msm_drm_private *priv = minor->dev->dev_private;
 	struct msm_perf_state *perf;
-	struct dentry *ent;
 
 	/* only create on first minor: */
 	if (priv->perf)
@@ -220,19 +219,9 @@ int msm_perf_debugfs_init(struct drm_minor *minor)
 	mutex_init(&perf->read_lock);
 	priv->perf = perf;
 
-	ent = debugfs_create_file("perf", S_IFREG | S_IRUGO,
-			minor->debugfs_root, perf, &perf_debugfs_fops);
-	if (!ent) {
-		DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/perf\n",
-				minor->debugfs_root);
-		goto fail;
-	}
-
+	debugfs_create_file("perf", S_IFREG | S_IRUGO, minor->debugfs_root,
+			    perf, &perf_debugfs_fops);
 	return 0;
-
-fail:
-	msm_perf_debugfs_cleanup(priv);
-	return -1;
 }
 
 void msm_perf_debugfs_cleanup(struct msm_drm_private *priv)
diff --git a/drivers/gpu/drm/msm/msm_rd.c b/drivers/gpu/drm/msm/msm_rd.c
index d21172933d92..46f7eb6a7eaa 100644
--- a/drivers/gpu/drm/msm/msm_rd.c
+++ b/drivers/gpu/drm/msm/msm_rd.c
@@ -244,7 +244,6 @@ static void rd_cleanup(struct msm_rd_state *rd)
 static struct msm_rd_state *rd_init(struct drm_minor *minor, const char *name)
 {
 	struct msm_rd_state *rd;
-	struct dentry *ent;
 	int ret = 0;
 
 	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
@@ -258,20 +257,10 @@ static struct msm_rd_state *rd_init(struct drm_minor *minor, const char *name)
 
 	init_waitqueue_head(&rd->fifo_event);
 
-	ent = debugfs_create_file(name, S_IFREG | S_IRUGO,
-			minor->debugfs_root, rd, &rd_debugfs_fops);
-	if (!ent) {
-		DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/%s\n",
-				minor->debugfs_root, name);
-		ret = -ENOMEM;
-		goto fail;
-	}
+	debugfs_create_file(name, S_IFREG | S_IRUGO, minor->debugfs_root, rd,
+			    &rd_debugfs_fops);
 
 	return rd;
-
-fail:
-	rd_cleanup(rd);
-	return ERR_PTR(ret);
 }
 
 int msm_rd_debugfs_init(struct drm_minor *minor)
-- 
2.22.0

[PATCH] msm: no need to check return value of debugfs_create functions

[Greg Kroah-Hartman]

When calling debugfs functions, there is no need to ever check the
return value.  The function can work or not, but the code logic should
never do something different based on this.

Cc: Rob Clark <robdclark@gmail.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: linux-arm-msm@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: freedreno@lists.freedesktop.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/msm/msm_perf.c | 15 ++-------------
 drivers/gpu/drm/msm/msm_rd.c   | 15 ++-------------
 2 files changed, 4 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_perf.c b/drivers/gpu/drm/msm/msm_perf.c
index 5ab21bd2decb..95948cfe7a12 100644
--- a/drivers/gpu/drm/msm/msm_perf.c
+++ b/drivers/gpu/drm/msm/msm_perf.c
@@ -205,7 +205,6 @@ int msm_perf_debugfs_init(struct drm_minor *minor)
 {
 	struct msm_drm_private *priv = minor->dev->dev_private;
 	struct msm_perf_state *perf;
-	struct dentry *ent;
 
 	/* only create on first minor: */
 	if (priv->perf)
@@ -220,19 +219,9 @@ int msm_perf_debugfs_init(struct drm_minor *minor)
 	mutex_init(&perf->read_lock);
 	priv->perf = perf;
 
-	ent = debugfs_create_file("perf", S_IFREG | S_IRUGO,
-			minor->debugfs_root, perf, &perf_debugfs_fops);
-	if (!ent) {
-		DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/perf\n",
-				minor->debugfs_root);
-		goto fail;
-	}
-
+	debugfs_create_file("perf", S_IFREG | S_IRUGO, minor->debugfs_root,
+			    perf, &perf_debugfs_fops);
 	return 0;
-
-fail:
-	msm_perf_debugfs_cleanup(priv);
-	return -1;
 }
 
 void msm_perf_debugfs_cleanup(struct msm_drm_private *priv)
diff --git a/drivers/gpu/drm/msm/msm_rd.c b/drivers/gpu/drm/msm/msm_rd.c
index d21172933d92..46f7eb6a7eaa 100644
--- a/drivers/gpu/drm/msm/msm_rd.c
+++ b/drivers/gpu/drm/msm/msm_rd.c
@@ -244,7 +244,6 @@ static void rd_cleanup(struct msm_rd_state *rd)
 static struct msm_rd_state *rd_init(struct drm_minor *minor, const char *name)
 {
 	struct msm_rd_state *rd;
-	struct dentry *ent;
 	int ret = 0;
 
 	rd = kzalloc(sizeof(*rd), GFP_KERNEL);
@@ -258,20 +257,10 @@ static struct msm_rd_state *rd_init(struct drm_minor *minor, const char *name)
 
 	init_waitqueue_head(&rd->fifo_event);
 
-	ent = debugfs_create_file(name, S_IFREG | S_IRUGO,
-			minor->debugfs_root, rd, &rd_debugfs_fops);
-	if (!ent) {
-		DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/%s\n",
-				minor->debugfs_root, name);
-		ret = -ENOMEM;
-		goto fail;
-	}
+	debugfs_create_file(name, S_IFREG | S_IRUGO, minor->debugfs_root, rd,
+			    &rd_debugfs_fops);
 
 	return rd;
-
-fail:
-	rd_cleanup(rd);
-	return ERR_PTR(ret);
 }
 
 int msm_rd_debugfs_init(struct drm_minor *minor)
-- 
2.22.0

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Re: [PATCH] msm: no need to check return value of debugfs_create functions

[Marc Gonzalez]

On 13/06/2019 14:24, Greg Kroah-Hartman wrote:

> When calling debugfs functions, there is no need to ever check the
> return value.  The function can work or not, but the code logic should
> never do something different based on this.

Naive question: if callers are supposed to ignore the return value,
why not change the prototype to void (no return value) ?

Regards.

Re: [PATCH] msm: no need to check return value of debugfs_create functions

[Greg Kroah-Hartman]

On Thu, Jun 13, 2019 at 02:37:46PM +0200, Marc Gonzalez wrote:
> On 13/06/2019 14:24, Greg Kroah-Hartman wrote:
> 
> > When calling debugfs functions, there is no need to ever check the
> > return value.  The function can work or not, but the code logic should
> > never do something different based on this.
> 
> Naive question: if callers are supposed to ignore the return value,
> why not change the prototype to void (no return value) ?

I am trying to do that, but sometimes you need the return value (like
for debugfs_create_dir()).  I have removed the return value from a
number of debugfs calls already, but the kernel is vast and big, and the
tendrils of debugfs use is deep, it is taking a while :)

Don't worry, there are more patches to come, this is just the first
wave.

thanks,

greg k-h