linux-kernel - [PATCH 4/6] x86: mm: no need to check return value of debugfs

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Date:   Tue, 22 Jan 2019 15:35:40 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org
Cc:     linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH 4/6] x86: mm: no need to check return value of debugfs_create functions

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: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: x86@...nel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/mm/debug_pagetables.c | 35 +++++++---------------------------
 1 file changed, 7 insertions(+), 28 deletions(-)

diff --git a/arch/x86/mm/debug_pagetables.c b/arch/x86/mm/debug_pagetables.c
index cd84f067e41d..1f23bea5da87 100644
--- a/arch/x86/mm/debug_pagetables.c
+++ b/arch/x86/mm/debug_pagetables.c
@@ -25,8 +25,6 @@ static int ptdump_curknl_show(struct seq_file *m, void *v)
 DEFINE_SHOW_ATTRIBUTE(ptdump_curknl);
 
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
-static struct dentry *pe_curusr;
-
 static int ptdump_curusr_show(struct seq_file *m, void *v)
 {
 	if (current->mm->pgd) {
@@ -41,8 +39,6 @@ DEFINE_SHOW_ATTRIBUTE(ptdump_curusr);
 #endif
 
 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
-static struct dentry *pe_efi;
-
 static int ptdump_efi_show(struct seq_file *m, void *v)
 {
 	if (efi_mm.pgd)
@@ -53,41 +49,24 @@ static int ptdump_efi_show(struct seq_file *m, void *v)
 DEFINE_SHOW_ATTRIBUTE(ptdump_efi);
 #endif
 
-static struct dentry *dir, *pe_knl, *pe_curknl;
+static struct dentry *dir;
 
 static int __init pt_dump_debug_init(void)
 {
 	dir = debugfs_create_dir("page_tables", NULL);
-	if (!dir)
-		return -ENOMEM;
-
-	pe_knl = debugfs_create_file("kernel", 0400, dir, NULL,
-				     &ptdump_fops);
-	if (!pe_knl)
-		goto err;
 
-	pe_curknl = debugfs_create_file("current_kernel", 0400,
-					dir, NULL, &ptdump_curknl_fops);
-	if (!pe_curknl)
-		goto err;
+	debugfs_create_file("kernel", 0400, dir, NULL, &ptdump_fops);
+	debugfs_create_file("current_kernel", 0400, dir, NULL,
+			    &ptdump_curknl_fops);
 
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
-	pe_curusr = debugfs_create_file("current_user", 0400,
-					dir, NULL, &ptdump_curusr_fops);
-	if (!pe_curusr)
-		goto err;
+	debugfs_create_file("current_user", 0400, dir, NULL,
+			    &ptdump_curusr_fops);
 #endif
-
 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
-	pe_efi = debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops);
-	if (!pe_efi)
-		goto err;
+	debugfs_create_file("efi", 0400, dir, NULL, &ptdump_efi_fops);
 #endif
-
 	return 0;
-err:
-	debugfs_remove_recursive(dir);
-	return -ENOMEM;
 }
 
 static void __exit pt_dump_debug_exit(void)
-- 
2.20.1