linux-kernel - Re: [PATCH 1/3] RAS: Export ras_debugfs

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Date: Mon, 26 Feb 2024 16:43:39 +0100
From: Borislav Petkov <bp@...en8.de>
To: Yazen Ghannam <yazen.ghannam@....com>
Cc: tony.luck@...el.com, linux-edac@...r.kernel.org,
	linux-kernel@...r.kernel.org, avadhut.naik@....com,
	john.allen@....com, muralidhara.mk@....com, sathyapriya.k@....com,
	naveenkrishna.chatradhi@....com
Subject: Re: [PATCH 1/3] RAS: Export ras_debugfs_dir

On Mon, Feb 26, 2024 at 09:29:39AM -0600, Yazen Ghannam wrote:
> ...so that RAS modules can use it.
> 
> Signed-off-by: Yazen Ghannam <yazen.ghannam@....com>
> ---
>  drivers/ras/debugfs.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/ras/debugfs.c b/drivers/ras/debugfs.c
> index ffb973c328e3..fd3d4595c122 100644
> --- a/drivers/ras/debugfs.c
> +++ b/drivers/ras/debugfs.c
> @@ -4,6 +4,7 @@
>  #include "debugfs.h"
>  
>  struct dentry *ras_debugfs_dir;
> +EXPORT_SYMBOL_GPL(ras_debugfs_dir);

I am never a fan of exporting things so let's add a helper this first,
in a separate pre-patch.

Also, I'd like to have this:

-       fmpm_dfs_dir = debugfs_create_dir(KBUILD_MODNAME, ras_debugfs_dir);
+       fmpm_dfs_dir = debugfs_create_dir("fmpm", dfs);

so that we don't accidentally change the module name and fsck up scripts
in the process.

Thx.

---

diff --git a/drivers/ras/amd/fmpm.c b/drivers/ras/amd/fmpm.c
index e0811a71e6e7..b8e3e4c81f7e 100644
--- a/drivers/ras/amd/fmpm.c
+++ b/drivers/ras/amd/fmpm.c
@@ -913,10 +913,13 @@ static const struct file_operations fmpm_fops = {
 
 static void setup_debugfs(void)
 {
-	if (!ras_debugfs_dir)
+	struct dentry *dfs;
+
+	dfs = ras_get_debugfs_root();
+	if (!dfs)
 		return;
 
-	fmpm_dfs_dir = debugfs_create_dir(KBUILD_MODNAME, ras_debugfs_dir);
+	fmpm_dfs_dir = debugfs_create_dir("fmpm", dfs);
 	if (!fmpm_dfs_dir)
 		return;
 
diff --git a/drivers/ras/cec.c b/drivers/ras/cec.c
index 321af498ee11..e440b15fbabc 100644
--- a/drivers/ras/cec.c
+++ b/drivers/ras/cec.c
@@ -480,9 +480,15 @@ DEFINE_SHOW_ATTRIBUTE(array);
 
 static int __init create_debugfs_nodes(void)
 {
-	struct dentry *d, *pfn, *decay, *count, *array;
+	struct dentry *d, *pfn, *decay, *count, *array, *dfs;
 
-	d = debugfs_create_dir("cec", ras_debugfs_dir);
+	dfs = ras_get_debugfs_root();
+	if (!dfs) {
+		pr_warn("Error getting RAS debugfs root!\n");
+		return -1;
+	}
+
+	d = debugfs_create_dir("cec", dfs);
 	if (!d) {
 		pr_warn("Error creating cec debugfs node!\n");
 		return -1;
diff --git a/drivers/ras/debugfs.c b/drivers/ras/debugfs.c
index fd3d4595c122..42afd3de68b2 100644
--- a/drivers/ras/debugfs.c
+++ b/drivers/ras/debugfs.c
@@ -3,11 +3,16 @@
 #include <linux/ras.h>
 #include "debugfs.h"
 
-struct dentry *ras_debugfs_dir;
-EXPORT_SYMBOL_GPL(ras_debugfs_dir);
+static struct dentry *ras_debugfs_dir;
 
 static atomic_t trace_count = ATOMIC_INIT(0);
 
+struct dentry *ras_get_debugfs_root(void)
+{
+	return ras_debugfs_dir;
+}
+EXPORT_SYMBOL_GPL(ras_get_debugfs_root);
+
 int ras_userspace_consumers(void)
 {
 	return atomic_read(&trace_count);
diff --git a/drivers/ras/debugfs.h b/drivers/ras/debugfs.h
index c07443b462ad..4749ccdeeba1 100644
--- a/drivers/ras/debugfs.h
+++ b/drivers/ras/debugfs.h
@@ -4,6 +4,6 @@
 
 #include <linux/debugfs.h>
 
-extern struct dentry *ras_debugfs_dir;
+struct dentry *ras_get_debugfs_root(void);
 
 #endif /* __RAS_DEBUGFS_H__ */

-- 
Regards/Gruss,
    Boris.

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