Re: [PATCH v2 4/4] arch/x86/events/intel: Convert snprintf/sprintf to sysfs_emit

From: Adrian Hunter
Date: Wed Feb 07 2024 - 03:12:38 EST

On 26/01/24 08:13, Li Zhijian wrote:
> Per filesystems/sysfs.rst, show() should only use sysfs_emit()
> or sysfs_emit_at() when formatting the value to be returned to user space.
>
> coccinelle complains that there are still a couple of functions that use
> snprintf(). Convert them to sysfs_emit().
>
>> ./arch/x86/events/intel/core.c:5614:8-16: WARNING: please use sysfs_emit or sysfs_emit_at
>> ./arch/x86/events/intel/core.c:5623:8-16: WARNING: please use sysfs_emit or sysfs_emit_at
>> ./arch/x86/events/intel/core.c:5605:8-16: WARNING: please use sysfs_emit or sysfs_emit_at
>> ./arch/x86/events/intel/core.c:5651:8-16: WARNING: please use sysfs_emit or sysfs_emit_at
>> ./arch/x86/events/intel/core.c:5571:8-16: WARNING: please use sysfs_emit or sysfs_emit_at
>
> Most of this patch is generated by:
> $ make coccicheck MODE=patch COCCI=scripts/coccinelle/api/device_attr_show.cocci M=arch/x86/events/intel | sed -n '6,$p' | patch -p1
>
> No functional change intended
>
> CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> CC: Ingo Molnar <mingo@xxxxxxxxxx>
> CC: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> CC: Mark Rutland <mark.rutland@xxxxxxx>
> CC: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> CC: Jiri Olsa <jolsa@xxxxxxxxxx>
> CC: Namhyung Kim <namhyung@xxxxxxxxxx>
> CC: Ian Rogers <irogers@xxxxxxxxxx>
> CC: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> CC: Borislav Petkov <bp@xxxxxxxxx>
> CC: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> CC: x86@xxxxxxxxxx
> CC: "H. Peter Anvin" <hpa@xxxxxxxxx>
> CC: linux-perf-users@xxxxxxxxxxxxxxx
> Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxx>

Reviewed-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

> ---
> V2:
> - Rebase to v6.8-rc1(Fix 2 newly introduced abused cases)
> - Extract patch from the patch set[1] so that maintainer accept it separately.
> [1] https://lore.kernel.org/lkml/20240116041129.3937800-1-lizhijian@xxxxxxxxxxx/
> Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
> ---
> arch/x86/events/intel/core.c | 12 ++++++------
> arch/x86/events/intel/pt.c | 10 +++++-----
> arch/x86/events/intel/uncore.c | 2 +-
> arch/x86/events/intel/uncore_snbep.c | 2 +-
> 4 files changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index 3804f21ab049..7effb715dfaa 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -5517,7 +5517,7 @@ static ssize_t freeze_on_smi_show(struct device *cdev,
> struct device_attribute *attr,
> char *buf)
> {
> - return sprintf(buf, "%lu\n", x86_pmu.attr_freeze_on_smi);
> + return sysfs_emit(buf, "%lu\n", x86_pmu.attr_freeze_on_smi);
> }
>
> static DEFINE_MUTEX(freeze_on_smi_mutex);
> @@ -5568,7 +5568,7 @@ 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,
> @@ -5602,7 +5602,7 @@ 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);
> @@ -5611,7 +5611,7 @@ static ssize_t branch_counter_nr_show(struct device *cdev,
> struct device_attribute *attr,
> char *buf)
> {
> - return snprintf(buf, PAGE_SIZE, "%d\n", fls(x86_pmu.lbr_counters));
> + return sysfs_emit(buf, "%d\n", fls(x86_pmu.lbr_counters));
> }
>
> static DEVICE_ATTR_RO(branch_counter_nr);
> @@ -5620,7 +5620,7 @@ static ssize_t branch_counter_width_show(struct device *cdev,
> struct device_attribute *attr,
> char *buf)
> {
> - return snprintf(buf, PAGE_SIZE, "%d\n", LBR_INFO_BR_CNTR_BITS);
> + return sysfs_emit(buf, "%d\n", LBR_INFO_BR_CNTR_BITS);
> }
>
> static DEVICE_ATTR_RO(branch_counter_width);
> @@ -5648,7 +5648,7 @@ 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);
> diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
> index 8e2a12235e62..178238d096cd 100644
> --- a/arch/x86/events/intel/pt.c
> +++ b/arch/x86/events/intel/pt.c
> @@ -96,7 +96,7 @@ static ssize_t pt_cap_show(struct device *cdev,
> container_of(attr, struct dev_ext_attribute, attr);
> enum pt_capabilities cap = (long)ea->var;
>
> - return snprintf(buf, PAGE_SIZE, "%x\n", intel_pt_validate_hw_cap(cap));
> + return sysfs_emit(buf, "%x\n", intel_pt_validate_hw_cap(cap));
> }
>
> static struct attribute_group pt_cap_group __ro_after_init = {
> @@ -150,11 +150,11 @@ pt_timing_attr_show(struct device *dev, struct device_attribute *attr,
>
> switch (pmu_attr->id) {
> case 0:
> - return sprintf(page, "%lu\n", pt_pmu.max_nonturbo_ratio);
> + return sysfs_emit(page, "%lu\n", pt_pmu.max_nonturbo_ratio);
> case 1:
> - return sprintf(page, "%u:%u\n",
> - pt_pmu.tsc_art_num,
> - pt_pmu.tsc_art_den);
> + return sysfs_emit(page, "%u:%u\n",
> + pt_pmu.tsc_art_num,
> + pt_pmu.tsc_art_den);
> default:
> break;
> }
> diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
> index 7927c0b832fa..b6bb3aa286fe 100644
> --- a/arch/x86/events/intel/uncore.c
> +++ b/arch/x86/events/intel/uncore.c
> @@ -131,7 +131,7 @@ ssize_t uncore_event_show(struct device *dev,
> {
> struct uncore_event_desc *event =
> container_of(attr, struct uncore_event_desc, attr);
> - return sprintf(buf, "%s", event->config);
> + return sysfs_emit(buf, "%s", event->config);
> }
>
> struct intel_uncore_box *uncore_pmu_to_box(struct intel_uncore_pmu *pmu, int cpu)
> diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
> index a96496bef678..553ba9422677 100644
> --- a/arch/x86/events/intel/uncore_snbep.c
> +++ b/arch/x86/events/intel/uncore_snbep.c
> @@ -3754,7 +3754,7 @@ static ssize_t skx_iio_mapping_show(struct device *dev,
> long die = (long)ea->var;
> struct intel_uncore_topology *pmut = pmu_topology(pmu, die);
>
> - return sprintf(buf, "%04x:%02x\n", pmut ? pmut->iio->segment : 0,
> + return sysfs_emit(buf, "%04x:%02x\n", pmut ? pmut->iio->segment : 0,
> pmut ? pmut->iio->pci_bus_no : 0);
> }
>