x86/mm/dump_pagetables: Use DEFINE_SHOW_ATTRIBUTE()

Use DEFINE_SHOW_ATTRIBUTE() instead of open coding it.
Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: keescook@chromium.org
Cc: luto@kernel.org
Cc: peterz@infradead.org
Cc: bp@alien8.de
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/20181119154334.18265-1-tiny.windzz@gmail.com

arch/x86/mm/debug_pagetables.c

@@ -10,20 +10,9 @@ static int ptdump_show(struct seq_file *m, void *v)
 	return 0;
 }
 
-static int ptdump_open(struct inode *inode, struct file *filp)
-{
-	return single_open(filp, ptdump_show, NULL);
-}
-
-static const struct file_operations ptdump_fops = {
-	.owner		= THIS_MODULE,
-	.open		= ptdump_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
+DEFINE_SHOW_ATTRIBUTE(ptdump);
 
-static int ptdump_show_curknl(struct seq_file *m, void *v)
+static int ptdump_curknl_show(struct seq_file *m, void *v)
 {
 	if (current->mm->pgd) {
 		down_read(&current->mm->mmap_sem);
@@ -33,23 +22,12 @@ static int ptdump_show_curknl(struct seq_file *m, void *v)
 	return 0;
 }
 
-static int ptdump_open_curknl(struct inode *inode, struct file *filp)
-{
-	return single_open(filp, ptdump_show_curknl, NULL);
-}
-
-static const struct file_operations ptdump_curknl_fops = {
-	.owner		= THIS_MODULE,
-	.open		= ptdump_open_curknl,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
+DEFINE_SHOW_ATTRIBUTE(ptdump_curknl);
 
 #ifdef CONFIG_PAGE_TABLE_ISOLATION
 static struct dentry *pe_curusr;
 
-static int ptdump_show_curusr(struct seq_file *m, void *v)
+static int ptdump_curusr_show(struct seq_file *m, void *v)
 {
 	if (current->mm->pgd) {
 		down_read(&current->mm->mmap_sem);
@@ -59,42 +37,20 @@ static int ptdump_show_curusr(struct seq_file *m, void *v)
 	return 0;
 }
 
-static int ptdump_open_curusr(struct inode *inode, struct file *filp)
-{
-	return single_open(filp, ptdump_show_curusr, NULL);
-}
-
-static const struct file_operations ptdump_curusr_fops = {
-	.owner		= THIS_MODULE,
-	.open		= ptdump_open_curusr,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
+DEFINE_SHOW_ATTRIBUTE(ptdump_curusr);
 #endif
 
 #if defined(CONFIG_EFI) && defined(CONFIG_X86_64)
 static struct dentry *pe_efi;
 
-static int ptdump_show_efi(struct seq_file *m, void *v)
+static int ptdump_efi_show(struct seq_file *m, void *v)
 {
 	if (efi_mm.pgd)
 		ptdump_walk_pgd_level_debugfs(m, efi_mm.pgd, false);
 	return 0;
 }
 
-static int ptdump_open_efi(struct inode *inode, struct file *filp)
-{
-	return single_open(filp, ptdump_show_efi, NULL);
-}
-
-static const struct file_operations ptdump_efi_fops = {
-	.owner		= THIS_MODULE,
-	.open		= ptdump_open_efi,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
+DEFINE_SHOW_ATTRIBUTE(ptdump_efi);
 #endif
 
 static struct dentry *dir, *pe_knl, *pe_curknl;