[PATCH 3/3] perf/x86/intel: Use sysfs_emit() in show() callback function
From: Deepak R Varma
Date: Fri Feb 17 2023 - 11:01:03 EST
Using sprintf/snprintf functions are error prone and suggested to be
replaced by scnprintf/vscnrptintf as outlined in this [1] LWN article.
A more recent recommendation is to use sysfs_emit() or sysfs_emit_at()
as per Documentation/filesystems/sysfs.rst in show() callback function
when formatting values to be returned to user-space. These helper
functions are PAGE_SIZE aware and wrap a safer call to vscnprintf().
[1] https://lwn.net/Articles/69419/
Issue identified using the coccinelle device_attr_show.cocci script.
Signed-off-by: Deepak R Varma <drv@xxxxxxxxx>
---
arch/x86/events/intel/core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index bafdc2be479a..8fb1225123ef 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -5273,7 +5273,7 @@ static ssize_t show_sysctl_tfa(struct device *cdev,
struct device_attribute *attr,
char *buf)
{
- return snprintf(buf, 40, "%d\n", allow_tsx_force_abort);
+ return sysfs_emit(buf, "%d\n", allow_tsx_force_abort);
}
static ssize_t set_sysctl_tfa(struct device *cdev,
@@ -5307,7 +5307,7 @@ static ssize_t branches_show(struct device *cdev,
struct device_attribute *attr,
char *buf)
{
- return snprintf(buf, PAGE_SIZE, "%d\n", x86_pmu.lbr_nr);
+ return sysfs_emit(buf, "%d\n", x86_pmu.lbr_nr);
}
static DEVICE_ATTR_RO(branches);
@@ -5323,7 +5323,7 @@ static ssize_t pmu_name_show(struct device *cdev,
struct device_attribute *attr,
char *buf)
{
- return snprintf(buf, PAGE_SIZE, "%s\n", pmu_name_str);
+ return sysfs_emit(buf, "%s\n", pmu_name_str);
}
static DEVICE_ATTR_RO(pmu_name);
--
2.34.1