mmflags.h: use less error prone method to define pageflag_names

Patch series "mm, printk: introduce new format for page_type", v4.

This series moves PG_slab page flag to page_type, freeing one bit in
page->flags and introduces %pGt format that prints human-readable
page_type like %pGp for printing page flags.

See changelog of patch 2 for more implementation details.

Thanks everyone that gave valuable comments.


This patch (of 3):

Use helper macro to decrease chances of typo when defining pageflag_names.

Link: https://lkml.kernel.org/r/20230130042514.2418-1-42.hyeyoo@gmail.com
Link: https://lore.kernel.org/lkml/Y6AycLbpjVzXM5I9@smile.fi.intel.com
Link: https://lkml.kernel.org/r/20230130042514.2418-2-42.hyeyoo@gmail.comSigned-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/trace/events/mmflags.h

@@ -67,71 +67,74 @@
 	) : "none"
 
 #ifdef CONFIG_MMU
-#define IF_HAVE_PG_MLOCK(flag,string) ,{1UL << flag, string}
+#define IF_HAVE_PG_MLOCK(_name) ,{1UL << PG_##_name, __stringify(_name)}
 #else
-#define IF_HAVE_PG_MLOCK(flag,string)
+#define IF_HAVE_PG_MLOCK(_name)
 #endif
 
 #ifdef CONFIG_ARCH_USES_PG_UNCACHED
-#define IF_HAVE_PG_UNCACHED(flag,string) ,{1UL << flag, string}
+#define IF_HAVE_PG_UNCACHED(_name) ,{1UL << PG_##_name, __stringify(_name)}
 #else
-#define IF_HAVE_PG_UNCACHED(flag,string)
+#define IF_HAVE_PG_UNCACHED(_name)
 #endif
 
 #ifdef CONFIG_MEMORY_FAILURE
-#define IF_HAVE_PG_HWPOISON(flag,string) ,{1UL << flag, string}
+#define IF_HAVE_PG_HWPOISON(_name) ,{1UL << PG_##_name, __stringify(_name)}
 #else
-#define IF_HAVE_PG_HWPOISON(flag,string)
+#define IF_HAVE_PG_HWPOISON(_name)
 #endif
 
 #if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
-#define IF_HAVE_PG_IDLE(flag,string) ,{1UL << flag, string}
+#define IF_HAVE_PG_IDLE(_name) ,{1UL << PG_##_name, __stringify(_name)}
 #else
-#define IF_HAVE_PG_IDLE(flag,string)
+#define IF_HAVE_PG_IDLE(_name)
 #endif
 
 #ifdef CONFIG_ARCH_USES_PG_ARCH_X
-#define IF_HAVE_PG_ARCH_X(flag,string) ,{1UL << flag, string}
+#define IF_HAVE_PG_ARCH_X(_name) ,{1UL << PG_##_name, __stringify(_name)}
 #else
-#define IF_HAVE_PG_ARCH_X(flag,string)
+#define IF_HAVE_PG_ARCH_X(_name)
 #endif
 
 #ifdef CONFIG_KASAN_HW_TAGS
-#define IF_HAVE_PG_SKIP_KASAN_POISON(flag,string) ,{1UL << flag, string}
+#define IF_HAVE_PG_SKIP_KASAN_POISON(_name) \
+	,{1UL << PG_##_name, __stringify(_name)}
 #else
-#define IF_HAVE_PG_SKIP_KASAN_POISON(flag,string)
+#define IF_HAVE_PG_SKIP_KASAN_POISON(_name)
 #endif
 
+#define DEF_PAGEFLAG_NAME(_name) { 1UL <<  PG_##_name, __stringify(_name) }
+
 #define __def_pageflag_names						\
-	{1UL << PG_locked,		"locked"	},		\
-	{1UL << PG_waiters,		"waiters"	},		\
-	{1UL << PG_error,		"error"		},		\
-	{1UL << PG_referenced,		"referenced"	},		\
-	{1UL << PG_uptodate,		"uptodate"	},		\
-	{1UL << PG_dirty,		"dirty"		},		\
-	{1UL << PG_lru,			"lru"		},		\
-	{1UL << PG_active,		"active"	},		\
-	{1UL << PG_workingset,		"workingset"	},		\
-	{1UL << PG_slab,		"slab"		},		\
-	{1UL << PG_owner_priv_1,	"owner_priv_1"	},		\
-	{1UL << PG_arch_1,		"arch_1"	},		\
-	{1UL << PG_reserved,		"reserved"	},		\
-	{1UL << PG_private,		"private"	},		\
-	{1UL << PG_private_2,		"private_2"	},		\
-	{1UL << PG_writeback,		"writeback"	},		\
-	{1UL << PG_head,		"head"		},		\
-	{1UL << PG_mappedtodisk,	"mappedtodisk"	},		\
-	{1UL << PG_reclaim,		"reclaim"	},		\
-	{1UL << PG_swapbacked,		"swapbacked"	},		\
-	{1UL << PG_unevictable,		"unevictable"	}		\
-IF_HAVE_PG_MLOCK(PG_mlocked,		"mlocked"	)		\
-IF_HAVE_PG_UNCACHED(PG_uncached,	"uncached"	)		\
-IF_HAVE_PG_HWPOISON(PG_hwpoison,	"hwpoison"	)		\
-IF_HAVE_PG_IDLE(PG_young,		"young"		)		\
-IF_HAVE_PG_IDLE(PG_idle,		"idle"		)		\
-IF_HAVE_PG_ARCH_X(PG_arch_2,		"arch_2"	)		\
-IF_HAVE_PG_ARCH_X(PG_arch_3,		"arch_3"	)		\
-IF_HAVE_PG_SKIP_KASAN_POISON(PG_skip_kasan_poison, "skip_kasan_poison")
+	DEF_PAGEFLAG_NAME(locked),					\
+	DEF_PAGEFLAG_NAME(waiters),					\
+	DEF_PAGEFLAG_NAME(error),					\
+	DEF_PAGEFLAG_NAME(referenced),					\
+	DEF_PAGEFLAG_NAME(uptodate),					\
+	DEF_PAGEFLAG_NAME(dirty),					\
+	DEF_PAGEFLAG_NAME(lru),						\
+	DEF_PAGEFLAG_NAME(active),					\
+	DEF_PAGEFLAG_NAME(workingset),					\
+	DEF_PAGEFLAG_NAME(slab),					\
+	DEF_PAGEFLAG_NAME(owner_priv_1),				\
+	DEF_PAGEFLAG_NAME(arch_1),					\
+	DEF_PAGEFLAG_NAME(reserved),					\
+	DEF_PAGEFLAG_NAME(private),					\
+	DEF_PAGEFLAG_NAME(private_2),					\
+	DEF_PAGEFLAG_NAME(writeback),					\
+	DEF_PAGEFLAG_NAME(head),					\
+	DEF_PAGEFLAG_NAME(mappedtodisk),				\
+	DEF_PAGEFLAG_NAME(reclaim),					\
+	DEF_PAGEFLAG_NAME(swapbacked),					\
+	DEF_PAGEFLAG_NAME(unevictable)					\
+IF_HAVE_PG_MLOCK(mlocked)						\
+IF_HAVE_PG_UNCACHED(uncached)						\
+IF_HAVE_PG_HWPOISON(hwpoison)						\
+IF_HAVE_PG_IDLE(idle)							\
+IF_HAVE_PG_IDLE(young)							\
+IF_HAVE_PG_ARCH_X(arch_2)						\
+IF_HAVE_PG_ARCH_X(arch_3)						\
+IF_HAVE_PG_SKIP_KASAN_POISON(skip_kasan_poison)
 
 #define show_page_flags(flags)						\
 	(flags) ? __print_flags(flags, "|",				\