linux-kernel - [PATCH v1 4/7] panic: sys_info: Replace struct sys_info

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Message-ID: <20250711095413.1472448-5-andriy.shevchenko@linux.intel.com>
Date: Fri, 11 Jul 2025 12:51:10 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Feng Tang <feng.tang@...ux.alibaba.com>,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	linux-kernel@...r.kernel.org
Cc: Andrew Morton <akpm@...ux-foundation.org>,
	Nathan Chancellor <nathan@...nel.org>
Subject: [PATCH v1 4/7] panic: sys_info: Replace struct sys_info_name with plain array of strings

There is no need to keep a custom structure just for the need of
a plain array of strings. Replace struct sys_info_name with plain
array of strings.

With that done, simplify the code, in particular, naturally use
for_each_set_bit() when iterating over si_bits_global bitmap.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 lib/sys_info.c | 47 ++++++++++++++++++++---------------------------
 1 file changed, 20 insertions(+), 27 deletions(-)

diff --git a/lib/sys_info.c b/lib/sys_info.c
index 5d98560f3f53..7965984c6d67 100644
--- a/lib/sys_info.c
+++ b/lib/sys_info.c
@@ -1,30 +1,28 @@
 // SPDX-License-Identifier: GPL-2.0-only
-#include <linux/sched/debug.h>
+#include <linux/bitops.h>
 #include <linux/console.h>
+#include <linux/log2.h>
 #include <linux/kernel.h>
 #include <linux/ftrace.h>
-#include <linux/sysctl.h>
 #include <linux/nmi.h>
+#include <linux/sched/debug.h>
+#include <linux/string.h>
+#include <linux/sysctl.h>
 
 #include <linux/sys_info.h>
 
-struct sys_info_name {
-	unsigned long bit;
-	const char *name;
-};
-
 /*
  * When 'si_names' gets updated,  please make sure the 'sys_info_avail'
  * below is updated accordingly.
  */
-static const struct sys_info_name  si_names[] = {
-	{ SYS_INFO_TASKS,		"tasks" },
-	{ SYS_INFO_MEM,			"mem" },
-	{ SYS_INFO_TIMERS,		"timers" },
-	{ SYS_INFO_LOCKS,		"locks" },
-	{ SYS_INFO_FTRACE,		"ftrace" },
-	{ SYS_INFO_ALL_BT,		"all_bt" },
-	{ SYS_INFO_BLOCKED_TASKS,	"blocked_tasks" },
+static const char * const si_names[] = {
+	[ilog2(SYS_INFO_TASKS)]		= "tasks",
+	[ilog2(SYS_INFO_MEM)]		= "mem",
+	[ilog2(SYS_INFO_TIMERS)]	= "timers",
+	[ilog2(SYS_INFO_LOCKS)]		= "locks",
+	[ilog2(SYS_INFO_FTRACE)]	= "ftrace",
+	[ilog2(SYS_INFO_ALL_BT)]	= "all_bt",
+	[ilog2(SYS_INFO_BLOCKED_TASKS)]	= "blocked_tasks",
 };
 
 /* Expecting string like "xxx_sys_info=tasks,mem,timers,locks,ftrace,..." */
@@ -36,12 +34,9 @@ unsigned long sys_info_parse_param(char *str)
 
 	s = str;
 	while ((name = strsep(&s, ",")) && *name) {
-		for (i = 0; i < ARRAY_SIZE(si_names); i++) {
-			if (!strcmp(name, si_names[i].name)) {
-				si_bits |= si_names[i].bit;
-				break;
-			}
-		}
+		i = match_string(si_names, ARRAY_SIZE(si_names), name);
+		if (i >= 0)
+			__set_bit(i, &si_bits);
 	}
 
 	return si_bits;
@@ -84,12 +79,10 @@ int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write,
 		/* The access to the global value is not synchronized. */
 		si_bits = READ_ONCE(*si_bits_global);
 
-		for (i = 0; i < ARRAY_SIZE(si_names); i++) {
-			if (si_bits & si_names[i].bit) {
-				len += scnprintf(names + len, sizeof(names) - len,
-					"%s%s", delim, si_names[i].name);
-				delim = ",";
-			}
+		for_each_set_bit(i, &si_bits, ARRAY_SIZE(si_names)) {
+			len += scnprintf(names + len, sizeof(names) - len,
+					 "%s%s", delim, si_names[i]);
+			delim = ",";
 		}
 
 		table = *ro_table;
-- 
2.47.2