[PATCH v4 09/11] powerpc/papr_scm: Return the string length from the sysfs show functions

[Kees Cook <kees@kernel.org>]

perf_stats_show() and flags_show() build their output with a seq_buf
and return seq_buf_used(), which may include the trailing NUL byte
when the seq_buf has overflowed. Use seq_buf_strlen() instead. As
suggested in review, use it as well for flags_show()'s check whether
any flag was printed.

Build tested ARCH=powerpc ppc64_defconfig with GCC powerpc64-linux-gnu
16.2.0:
arch/powerpc/platforms/pseries/papr_scm.o

Assisted-by: LLM
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Kees Cook <kees@kernel.org>
---
 arch/powerpc/platforms/pseries/papr_scm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 75da96c08cdd..5c3bf06bb59b 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -1108,7 +1108,7 @@ static ssize_t perf_stats_show(struct device *dev,
 
 free_stats:
 	kfree(stats);
-	return rc ? rc : (ssize_t)seq_buf_used(&s);
+	return rc ?: (ssize_t)seq_buf_strlen(&s);
 }
 static DEVICE_ATTR_ADMIN_RO(perf_stats);
 
@@ -1147,10 +1147,10 @@ static ssize_t flags_show(struct device *dev,
 	if (health & PAPR_PMEM_SCRUBBED_AND_LOCKED)
 		seq_buf_printf(&s, "scrubbed locked ");
 
-	if (seq_buf_used(&s))
+	if (seq_buf_strlen(&s))
 		seq_buf_printf(&s, "\n");
 
-	return seq_buf_used(&s);
+	return seq_buf_strlen(&s);
 }
 DEVICE_ATTR_RO(flags);
 
-- 
2.55.0