[PATCH] fault-inject: clean up debugfs file creation logic

[PATCH] fault-inject: clean up debugfs file creation logic

[Greg Kroah-Hartman]

There is no need to check the return value of a debugfs_create_file
call, a caller should never change what they do depending on if debugfs
is working properly or not, so remove the checks, simplifying the logic
in the file a lot.

Also fix up the error check for debugfs_create_dir() which was not
returning NULL for an error, but rather a error pointer.

Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 lib/fault-inject.c | 73 +++++++++++++++++-----------------------------
 1 file changed, 26 insertions(+), 47 deletions(-)

diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index 3cb21b2bf088..8186ca84910b 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -166,10 +166,10 @@ static int debugfs_ul_get(void *data, u64 *val)
 
 DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
 
-static struct dentry *debugfs_create_ul(const char *name, umode_t mode,
-				struct dentry *parent, unsigned long *value)
+static void debugfs_create_ul(const char *name, umode_t mode,
+			      struct dentry *parent, unsigned long *value)
 {
-	return debugfs_create_file(name, mode, parent, value, &fops_ul);
+	debugfs_create_file(name, mode, parent, value, &fops_ul);
 }
 
 #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
@@ -185,12 +185,11 @@ static int debugfs_stacktrace_depth_set(void *data, u64 val)
 DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
 			debugfs_stacktrace_depth_set, "%llu\n");
 
-static struct dentry *debugfs_create_stacktrace_depth(
-	const char *name, umode_t mode,
-	struct dentry *parent, unsigned long *value)
+static void debugfs_create_stacktrace_depth(const char *name, umode_t mode,
+					    struct dentry *parent,
+					    unsigned long *value)
 {
-	return debugfs_create_file(name, mode, parent, value,
-				   &fops_stacktrace_depth);
+	debugfs_create_file(name, mode, parent, value, &fops_stacktrace_depth);
 }
 
 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
@@ -202,51 +201,31 @@ struct dentry *fault_create_debugfs_attr(const char *name,
 	struct dentry *dir;
 
 	dir = debugfs_create_dir(name, parent);
-	if (!dir)
-		return ERR_PTR(-ENOMEM);
-
-	if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
-		goto fail;
-	if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
-		goto fail;
-	if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
-		goto fail;
-	if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
-		goto fail;
-	if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
-		goto fail;
-	if (!debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir,
-				&attr->ratelimit_state.interval))
-		goto fail;
-	if (!debugfs_create_u32("verbose_ratelimit_burst", mode, dir,
-				&attr->ratelimit_state.burst))
-		goto fail;
-	if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
-		goto fail;
+	if (IS_ERR(dir))
+		return dir;
+
+	debugfs_create_ul("probability", mode, dir, &attr->probability);
+	debugfs_create_ul("interval", mode, dir, &attr->interval);
+	debugfs_create_atomic_t("times", mode, dir, &attr->times);
+	debugfs_create_atomic_t("space", mode, dir, &attr->space);
+	debugfs_create_ul("verbose", mode, dir, &attr->verbose);
+	debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir,
+			   &attr->ratelimit_state.interval);
+	debugfs_create_u32("verbose_ratelimit_burst", mode, dir,
+			   &attr->ratelimit_state.burst);
+	debugfs_create_bool("task-filter", mode, dir, &attr->task_filter);
 
 #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
-
-	if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
-				&attr->stacktrace_depth))
-		goto fail;
-	if (!debugfs_create_ul("require-start", mode, dir,
-				&attr->require_start))
-		goto fail;
-	if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
-		goto fail;
-	if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
-		goto fail;
-	if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
-		goto fail;
-
+	debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
+					&attr->stacktrace_depth);
+	debugfs_create_ul("require-start", mode, dir, &attr->require_start);
+	debugfs_create_ul("require-end", mode, dir, &attr->require_end);
+	debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
+	debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
 #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
 
 	attr->dname = dget(dir);
 	return dir;
-fail:
-	debugfs_remove_recursive(dir);
-
-	return ERR_PTR(-ENOMEM);
 }
 EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
 
-- 
2.22.0

Re: [PATCH] fault-inject: clean up debugfs file creation logic

[Akinobu Mita]

2019年6月12日(水) 18:58 Greg Kroah-Hartman <gregkh@linuxfoundation.org>:
>
> There is no need to check the return value of a debugfs_create_file
> call, a caller should never change what they do depending on if debugfs
> is working properly or not, so remove the checks, simplifying the logic
> in the file a lot.
>
> Also fix up the error check for debugfs_create_dir() which was not
> returning NULL for an error, but rather a error pointer.
>
> Cc: Akinobu Mita <akinobu.mita@gmail.com>
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Looks good.

Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>