[PATCH v2 1/2] bug: do refactoring allowing to add a warning handling action

[Alexander Popov <alex.popov@linux.com>]

Do refactoring that allows adding a warning handling action,
in particular, pkill_on_warn. No functional changes intended.

Signed-off-by: Alexander Popov <alex.popov@linux.com>
---
 include/asm-generic/bug.h | 31 +++++++++++++++++++++----------
 lib/bug.c                 | 19 +++++++++++++------
 2 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index edb0e2a602a8..881aeaf5a2d5 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -91,7 +91,15 @@ void warn_slowpath_fmt(const char *file, const int line, unsigned taint,
 		warn_slowpath_fmt(__FILE__, __LINE__, taint, arg);	\
 		instrumentation_end();					\
 	} while (0)
-#else
+#ifndef WARN_ON_ONCE
+#define WARN_ON_ONCE(condition) ({					\
+	int __ret_warn_on = !!(condition);				\
+	if (unlikely(__ret_warn_on))					\
+		DO_ONCE_LITE(__WARN_printf, TAINT_WARN, NULL);		\
+	unlikely(__ret_warn_on);					\
+})
+#endif
+#else /* __WARN_FLAGS */
 extern __printf(1, 2) void __warn_printk(const char *fmt, ...);
 #define __WARN()		__WARN_FLAGS(BUGFLAG_TAINT(TAINT_WARN))
 #define __WARN_printf(taint, arg...) do {				\
@@ -141,16 +149,19 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
 	unlikely(__ret_warn_on);					\
 })
 
-#ifndef WARN_ON_ONCE
-#define WARN_ON_ONCE(condition)					\
-	DO_ONCE_LITE_IF(condition, WARN_ON, 1)
-#endif
-
-#define WARN_ONCE(condition, format...)				\
-	DO_ONCE_LITE_IF(condition, WARN, 1, format)
+#define WARN_ONCE(condition, format...) ({				\
+	int __ret_warn_on = !!(condition);				\
+	if (unlikely(__ret_warn_on))					\
+		DO_ONCE_LITE(__WARN_printf, TAINT_WARN, format);	\
+	unlikely(__ret_warn_on);					\
+})
 
-#define WARN_TAINT_ONCE(condition, taint, format...)		\
-	DO_ONCE_LITE_IF(condition, WARN_TAINT, 1, taint, format)
+#define WARN_TAINT_ONCE(condition, taint, format...) ({			\
+	int __ret_warn_on = !!(condition);				\
+	if (unlikely(__ret_warn_on))					\
+		DO_ONCE_LITE(__WARN_printf, taint, format);		\
+	unlikely(__ret_warn_on);					\
+})
 
 #else /* !CONFIG_BUG */
 #ifndef HAVE_ARCH_BUG
diff --git a/lib/bug.c b/lib/bug.c
index 45a0584f6541..1a91f01412b8 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -156,16 +156,17 @@ struct bug_entry *find_bug(unsigned long bugaddr)
 
 enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 {
+	enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
 	struct bug_entry *bug;
 	const char *file;
 	unsigned line, warning, once, done;
 
 	if (!is_valid_bugaddr(bugaddr))
-		return BUG_TRAP_TYPE_NONE;
+		goto out;
 
 	bug = find_bug(bugaddr);
 	if (!bug)
-		return BUG_TRAP_TYPE_NONE;
+		goto out;
 
 	disable_trace_on_warning();
 
@@ -176,8 +177,10 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 	done = (bug->flags & BUGFLAG_DONE) != 0;
 
 	if (warning && once) {
-		if (done)
-			return BUG_TRAP_TYPE_WARN;
+		if (done) {
+			bug_type = BUG_TRAP_TYPE_WARN;
+			goto out;
+		}
 
 		/*
 		 * Since this is the only store, concurrency is not an issue.
@@ -198,7 +201,8 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 		/* this is a WARN_ON rather than BUG/BUG_ON */
 		__warn(file, line, (void *)bugaddr, BUG_GET_TAINT(bug), regs,
 		       NULL);
-		return BUG_TRAP_TYPE_WARN;
+		bug_type = BUG_TRAP_TYPE_WARN;
+		goto out;
 	}
 
 	if (file)
@@ -207,7 +211,10 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 		pr_crit("Kernel BUG at %pB [verbose debug info unavailable]\n",
 			(void *)bugaddr);
 
-	return BUG_TRAP_TYPE_BUG;
+	bug_type = BUG_TRAP_TYPE_BUG;
+
+out:
+	return bug_type;
 }
 
 static void clear_once_table(struct bug_entry *start, struct bug_entry *end)
-- 
2.31.1