[PATCH 2/4] kernel/panic: convert print_tainted() to use struct seq_buf internally

From: Jani Nikula
Date: Fri May 31 2024 - 05:08:46 EST


Convert print_tainted() to use struct seq_buf internally in order to be
more aware of the buffer constraints as well as make it easier to extend
in follow-up work.

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
kernel/panic.c | 38 ++++++++++++++++++++++++--------------
1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index 5c9396418e1c..b7b2fb8b3625 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -35,6 +35,7 @@
#include <linux/debugfs.h>
#include <linux/sysfs.h>
#include <linux/context_tracking.h>
+#include <linux/seq_buf.h>
#include <trace/events/error_report.h>
#include <asm/sections.h>

@@ -497,6 +498,25 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
[ TAINT_TEST ] = { 'N', ' ', true },
};

+static void print_tainted_seq(struct seq_buf *s)
+{
+ int i;
+
+ if (!tainted_mask) {
+ seq_buf_puts(s, "Not tainted");
+ return;
+ }
+
+ seq_buf_printf(s, "Tainted: ");
+ for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
+ const struct taint_flag *t = &taint_flags[i];
+ bool is_set = test_bit(i, &tainted_mask);
+ char c = is_set ? t->c_true : t->c_false;
+
+ seq_buf_putc(s, c);
+ }
+}
+
/**
* print_tainted - return a string to represent the kernel taint state.
*
@@ -508,25 +528,15 @@ const struct taint_flag taint_flags[TAINT_FLAGS_COUNT] = {
const char *print_tainted(void)
{
static char buf[TAINT_FLAGS_COUNT + sizeof("Tainted: ")];
- char *s;
- int i;
+ struct seq_buf s;

BUILD_BUG_ON(ARRAY_SIZE(taint_flags) != TAINT_FLAGS_COUNT);

- if (!tainted_mask) {
- snprintf(buf, sizeof(buf), "Not tainted");
- return buf;
- }
+ seq_buf_init(&s, buf, sizeof(buf));

- s = buf + sprintf(buf, "Tainted: ");
- for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
- const struct taint_flag *t = &taint_flags[i];
- *s++ = test_bit(i, &tainted_mask) ?
- t->c_true : t->c_false;
- }
- *s = 0;
+ print_tainted_seq(&s);

- return buf;
+ return seq_buf_str(&s);
}

int test_taint(unsigned flag)
--
2.39.2