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@linux.intel.com>
---
 lib/sys_info.c | 44 ++++++++++++++++++++------------------------
 1 file changed, 20 insertions(+), 24 deletions(-)

diff --git a/lib/sys_info.c b/lib/sys_info.c
index 6b0188b30227..29a63238b31d 100644
--- a/lib/sys_info.c
+++ b/lib/sys_info.c
@@ -1,30 +1,29 @@
 // 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_PANIC_CONSOLE_REPLAY)]	= "",
+	[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 +35,9 @@ 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;
@@ -85,10 +81,10 @@ int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write,
 		si_bits = READ_ONCE(*si_bits_global);
 
 		names[0] = '\0';
-		for (i = 0; i < ARRAY_SIZE(si_names); i++) {
-			if (si_bits & si_names[i].bit) {
+		for_each_set_bit(i, &si_bits, ARRAY_SIZE(si_names)) {
+			if (*si_names[i]) {
 				len += scnprintf(names + len, sizeof(names) - len,
-					"%s%s", delim, si_names[i].name);
+						 "%s%s", delim, si_names[i]);
 				delim = ",";
 			}
 		}
-- 
2.50.1

On Thu, 30 Oct 2025 12:44:19 +0100 Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

> 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.
> 
> ...
>
> -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_PANIC_CONSOLE_REPLAY)]	= "",
> +	[ilog2(SYS_INFO_ALL_BT)]		= "all_bt",
> +	[ilog2(SYS_INFO_BLOCKED_TASKS)]		= "blocked_tasks",
>  };

We have this const_ilog2() which appears to exist to work around a
sparse shortcoming.  But only net/ethtool/common.c uses it - plenty of
other sites do what you've done.

Which makes me wonder whether const_ilog2() can be removed, switch
everything over to ilog2().

On Thu, Oct 30, 2025 at 08:06:16PM -0700, Andrew Morton wrote:
> On Thu, 30 Oct 2025 12:44:19 +0100 Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:

...

> > -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_PANIC_CONSOLE_REPLAY)]	= "",
> > +	[ilog2(SYS_INFO_ALL_BT)]		= "all_bt",
> > +	[ilog2(SYS_INFO_BLOCKED_TASKS)]		= "blocked_tasks",
> >  };
> 
> We have this const_ilog2() which appears to exist to work around a
> sparse shortcoming.  But only net/ethtool/common.c uses it - plenty of
> other sites do what you've done.
> 
> Which makes me wonder whether const_ilog2() can be removed, switch
> everything over to ilog2().

Good question. I haven't noticed sparse errors, I always use make W=1 C=1 for
my local builds.

-- 
With Best Regards,
Andy Shevchenko