[v6,2/2] power: refactor pstate and acpi code

  From: Anatoly Burakov <anatoly.burakov@intel.com>

Currently, ACPI and PSTATE modes have lots of code duplication,
confusing logic, and a bunch of other issues that can, and have, led to
various bugs and resource leaks.

This commit factors out the common parts of sysfs reading/writing for
ACPI and PSTATE drivers.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Signed-off-by: David Hunt <david.hunt@intel.com>

---
changes in v5
* fixed bugs raised by Richael Zhuang in review - open file rw+, etc.
* removed FOPS* and FOPEN* macros, which contained control statements.
* fixed some checkpatch warnings.
changes in v6
* fixed check of fputs return, negative on error.
---
 lib/power/meson.build            |   7 +
 lib/power/power_acpi_cpufreq.c   | 192 ++++------------
 lib/power/power_common.c         | 146 ++++++++++++
 lib/power/power_common.h         |  17 ++
 lib/power/power_pstate_cpufreq.c | 374 ++++++++++---------------------
 5 files changed, 335 insertions(+), 401 deletions(-)
  

On 23-Jun-21 1:03 PM, David Hunt wrote:
> From: Anatoly Burakov <anatoly.burakov@intel.com>
> 
> Currently, ACPI and PSTATE modes have lots of code duplication,
> confusing logic, and a bunch of other issues that can, and have, led to
> various bugs and resource leaks.
> 
> This commit factors out the common parts of sysfs reading/writing for
> ACPI and PSTATE drivers.
> 
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> Signed-off-by: David Hunt <david.hunt@intel.com>
> 
> ---
> changes in v5
> * fixed bugs raised by Richael Zhuang in review - open file rw+, etc.
> * removed FOPS* and FOPEN* macros, which contained control statements.
> * fixed some checkpatch warnings.
> changes in v6
> * fixed check of fputs return, negative on error.
> ---
>   lib/power/meson.build            |   7 +
>   lib/power/power_acpi_cpufreq.c   | 192 ++++------------
>   lib/power/power_common.c         | 146 ++++++++++++
>   lib/power/power_common.h         |  17 ++
>   lib/power/power_pstate_cpufreq.c | 374 ++++++++++---------------------
>   5 files changed, 335 insertions(+), 401 deletions(-)
> 
> diff --git a/lib/power/meson.build b/lib/power/meson.build
> index c1097d32f1..74c5f3a294 100644
> --- a/lib/power/meson.build
> +++ b/lib/power/meson.build
> @@ -5,6 +5,13 @@ if not is_linux
>       build = false
>       reason = 'only supported on Linux'
>   endif
> +
> +# we do some snprintf magic so silence format-nonliteral
> +flag_nonliteral = '-Wno-format-nonliteral'
> +if cc.has_argument(flag_nonliteral)
> +	cflags += flag_nonliteral
> +endif
> +

I'll do a more thorough review later, but i suspect that we can drop 
this, if we fix the functions to have a GCC printf format attribute:

https://gcc.gnu.org/onlinedocs/gcc-3.2/gcc/Function-Attributes.html

See "format" section. I'm not sure this is supported by other compilers 
though, so maybe it's better to keep it.
  

Hi,
It looks good to me.  I verified on arm platforms and didn't find any problem currently.

BR,
Richael
> -----Original Message-----
> From: David Hunt <david.hunt@intel.com>
> Sent: Wednesday, June 23, 2021 8:04 PM
> To: dev@dpdk.org
> Cc: david.hunt@intel.com; anatoly.burakov@intel.com; Richael Zhuang
> <Richael.Zhuang@arm.com>; stephen@networkplumber.org;
> reshma.pattan@intel.com; nd <nd@arm.com>
> Subject: [PATCH v6 2/2] power: refactor pstate and acpi code
> 
> From: Anatoly Burakov <anatoly.burakov@intel.com>
> 
> Currently, ACPI and PSTATE modes have lots of code duplication, confusing
> logic, and a bunch of other issues that can, and have, led to various bugs and
> resource leaks.
> 
> This commit factors out the common parts of sysfs reading/writing for ACPI
> and PSTATE drivers.
> 
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> Signed-off-by: David Hunt <david.hunt@intel.com>
> 
> ---
> changes in v5
> * fixed bugs raised by Richael Zhuang in review - open file rw+, etc.
> * removed FOPS* and FOPEN* macros, which contained control statements.
> * fixed some checkpatch warnings.
> changes in v6
> * fixed check of fputs return, negative on error.
> ---
>  lib/power/meson.build            |   7 +
>  lib/power/power_acpi_cpufreq.c   | 192 ++++------------
>  lib/power/power_common.c         | 146 ++++++++++++
>  lib/power/power_common.h         |  17 ++
>  lib/power/power_pstate_cpufreq.c | 374 ++++++++++---------------------
>  5 files changed, 335 insertions(+), 401 deletions(-)
> 
> diff --git a/lib/power/meson.build b/lib/power/meson.build index
> c1097d32f1..74c5f3a294 100644
> --- a/lib/power/meson.build
> +++ b/lib/power/meson.build
> @@ -5,6 +5,13 @@ if not is_linux
>      build = false
>      reason = 'only supported on Linux'
>  endif
> +
> +# we do some snprintf magic so silence format-nonliteral
> +flag_nonliteral = '-Wno-format-nonliteral'
> +if cc.has_argument(flag_nonliteral)
> +	cflags += flag_nonliteral
> +endif
> +
>  sources = files(
>          'guest_channel.c',
>          'power_acpi_cpufreq.c',
> diff --git a/lib/power/power_acpi_cpufreq.c
> b/lib/power/power_acpi_cpufreq.c index 1b8c69cc8b..9ca8d8a8f2 100644
> --- a/lib/power/power_acpi_cpufreq.c
> +++ b/lib/power/power_acpi_cpufreq.c
> @@ -19,41 +19,10 @@
>  #include "power_acpi_cpufreq.h"
>  #include "power_common.h"
> 
> -#ifdef RTE_LIBRTE_POWER_DEBUG
> -#define POWER_DEBUG_TRACE(fmt, args...) do { \
> -		RTE_LOG(ERR, POWER, "%s: " fmt, __func__, ## args); \
> -} while (0)
> -#else
> -#define POWER_DEBUG_TRACE(fmt, args...) -#endif
> -
> -#define FOPEN_OR_ERR_RET(f, retval) do { \
> -		if ((f) == NULL) { \
> -			RTE_LOG(ERR, POWER, "File not opened\n"); \
> -			return retval; \
> -		} \
> -} while (0)
> -
> -#define FOPS_OR_NULL_GOTO(ret, label) do { \
> -		if ((ret) == NULL) { \
> -			RTE_LOG(ERR, POWER, "fgets returns nothing\n"); \
> -			goto label; \
> -		} \
> -} while (0)
> -
> -#define FOPS_OR_ERR_GOTO(ret, label) do { \
> -		if ((ret) < 0) { \
> -			RTE_LOG(ERR, POWER, "File operations failed\n"); \
> -			goto label; \
> -		} \
> -} while (0)
> -
>  #define STR_SIZE     1024
>  #define POWER_CONVERT_TO_DECIMAL 10
> 
>  #define POWER_GOVERNOR_USERSPACE "userspace"
> -#define POWER_SYSFILE_GOVERNOR   \
> -		"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_governor"
>  #define POWER_SYSFILE_AVAIL_FREQ \
> 
> 	"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_available_frequen
> cies"
>  #define POWER_SYSFILE_SETSPEED   \
> @@ -135,53 +104,18 @@ set_freq_internal(struct acpi_power_info *pi,
> uint32_t idx)  static int  power_set_governor_userspace(struct
> acpi_power_info *pi)  {
> -	FILE *f;
> -	int ret = -1;
> -	char buf[BUFSIZ];
> -	char fullpath[PATH_MAX];
> -	char *s;
> -	int val;
> -
> -	snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_GOVERNOR,
> -			pi->lcore_id);
> -	f = fopen(fullpath, "rw+");
> -	FOPEN_OR_ERR_RET(f, ret);
> -
> -	s = fgets(buf, sizeof(buf), f);
> -	FOPS_OR_NULL_GOTO(s, out);
> -	/* Strip off terminating '\n' */
> -	strtok(buf, "\n");
> -
> -	/* Save the original governor */
> -	rte_strscpy(pi->governor_ori, buf, sizeof(pi->governor_ori));
> -
> -	/* Check if current governor is userspace */
> -	if (strncmp(buf, POWER_GOVERNOR_USERSPACE,
> -			sizeof(POWER_GOVERNOR_USERSPACE)) == 0) {
> -		ret = 0;
> -		POWER_DEBUG_TRACE("Power management governor of
> lcore %u is "
> -				"already userspace\n", pi->lcore_id);
> -		goto out;
> -	}
> -
> -	/* Write 'userspace' to the governor */
> -	val = fseek(f, 0, SEEK_SET);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	val = fputs(POWER_GOVERNOR_USERSPACE, f);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	/* We need to flush to see if the fputs succeeds */
> -	val = fflush(f);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	ret = 0;
> -	RTE_LOG(INFO, POWER, "Power management governor of lcore %u
> has been "
> -			"set to user space successfully\n", pi->lcore_id);
> -out:
> -	fclose(f);
> +	return power_set_governor(pi->lcore_id,
> POWER_GOVERNOR_USERSPACE,
> +			pi->governor_ori, sizeof(pi->governor_ori)); }
> 
> -	return ret;
> +/**
> + * It is to check the governor and then set the original governor back
> +if
> + * needed by writing the sys file.
> + */
> +static int
> +power_set_governor_original(struct acpi_power_info *pi) {
> +	return power_set_governor(pi->lcore_id, pi->governor_ori, NULL, 0);
>  }
> 
>  /**
> @@ -195,22 +129,22 @@ power_get_available_freqs(struct
> acpi_power_info *pi)
>  	int ret = -1, i, count;
>  	char *p;
>  	char buf[BUFSIZ];
> -	char fullpath[PATH_MAX];
>  	char *freqs[RTE_MAX_LCORE_FREQS];
> -	char *s;
> -
> -	snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_AVAIL_FREQ,
> -			pi->lcore_id);
> -	f = fopen(fullpath, "r");
> -	FOPEN_OR_ERR_RET(f, ret);
> 
> -	s = fgets(buf, sizeof(buf), f);
> -	FOPS_OR_NULL_GOTO(s, out);
> +	open_core_sysfs_file(POWER_SYSFILE_AVAIL_FREQ, pi->lcore_id, "r",
> +			&f);
> +	if (f == NULL) {
> +		RTE_LOG(ERR, POWER, "failed to open %s\n",
> +				POWER_SYSFILE_AVAIL_FREQ);
> +		goto out;
> +	}
> 
> -	/* Strip the line break if there is */
> -	p = strchr(buf, '\n');
> -	if (p != NULL)
> -		*p = 0;
> +	ret = read_core_sysfs_s(f, buf, sizeof(buf));
> +	if ((ret) < 0) {
> +		RTE_LOG(ERR, POWER, "Failed to read %s\n",
> +				POWER_SYSFILE_AVAIL_FREQ);
> +		goto out;
> +	}
> 
>  	/* Split string into at most RTE_MAX_LCORE_FREQS frequencies */
>  	count = rte_strsplit(buf, sizeof(buf), freqs, @@ -250,7 +184,8 @@
> power_get_available_freqs(struct acpi_power_info *pi)
>  	POWER_DEBUG_TRACE("%d frequency(s) of lcore %u are
> available\n",
>  			count, pi->lcore_id);
>  out:
> -	fclose(f);
> +	if (f != NULL)
> +		fclose(f);
> 
>  	return ret;
>  }
> @@ -262,18 +197,24 @@ static int
>  power_init_for_setting_freq(struct acpi_power_info *pi)  {
>  	FILE *f;
> -	char fullpath[PATH_MAX];
>  	char buf[BUFSIZ];
>  	uint32_t i, freq;
> -	char *s;
> +	int ret;
> 
> -	snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_SETSPEED,
> -			pi->lcore_id);
> -	f = fopen(fullpath, "rw+");
> -	FOPEN_OR_ERR_RET(f, -1);
> +	open_core_sysfs_file(POWER_SYSFILE_SETSPEED, pi->lcore_id, "rw+",
> +			&f);
> +	if (f == NULL) {
> +		RTE_LOG(ERR, POWER, "Failed to open %s\n",
> +				POWER_SYSFILE_SETSPEED);
> +		goto err;
> +	}
> 
> -	s = fgets(buf, sizeof(buf), f);
> -	FOPS_OR_NULL_GOTO(s, out);
> +	ret = read_core_sysfs_s(f, buf, sizeof(buf));
> +	if ((ret) < 0) {
> +		RTE_LOG(ERR, POWER, "Failed to read %s\n",
> +				POWER_SYSFILE_SETSPEED);
> +		goto err;
> +	}
> 
>  	freq = strtoul(buf, NULL, POWER_CONVERT_TO_DECIMAL);
>  	for (i = 0; i < pi->nb_freqs; i++) {
> @@ -284,8 +225,9 @@ power_init_for_setting_freq(struct acpi_power_info
> *pi)
>  		}
>  	}
> 
> -out:
> -	fclose(f);
> +err:
> +	if (f != NULL)
> +		fclose(f);
> 
>  	return -1;
>  }
> @@ -369,54 +311,6 @@ power_acpi_cpufreq_init(unsigned int lcore_id)
>  	return -1;
>  }
> 
> -/**
> - * It is to check the governor and then set the original governor back if
> - * needed by writing the sys file.
> - */
> -static int
> -power_set_governor_original(struct acpi_power_info *pi) -{
> -	FILE *f;
> -	int ret = -1;
> -	char buf[BUFSIZ];
> -	char fullpath[PATH_MAX];
> -	char *s;
> -	int val;
> -
> -	snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_GOVERNOR,
> -			pi->lcore_id);
> -	f = fopen(fullpath, "rw+");
> -	FOPEN_OR_ERR_RET(f, ret);
> -
> -	s = fgets(buf, sizeof(buf), f);
> -	FOPS_OR_NULL_GOTO(s, out);
> -
> -	/* Check if the governor to be set is the same as current */
> -	if (strncmp(buf, pi->governor_ori, sizeof(pi->governor_ori)) == 0) {
> -		ret = 0;
> -		POWER_DEBUG_TRACE("Power management governor of
> lcore %u "
> -				"has already been set to %s\n",
> -				pi->lcore_id, pi->governor_ori);
> -		goto out;
> -	}
> -
> -	/* Write back the original governor */
> -	val = fseek(f, 0, SEEK_SET);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	val = fputs(pi->governor_ori, f);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	ret = 0;
> -	RTE_LOG(INFO, POWER, "Power management governor of lcore %u "
> -			"has been set back to %s successfully\n",
> -			pi->lcore_id, pi->governor_ori);
> -out:
> -	fclose(f);
> -
> -	return ret;
> -}
> -
>  int
>  power_acpi_cpufreq_exit(unsigned int lcore_id)  { diff --git
> a/lib/power/power_common.c b/lib/power/power_common.c index
> 67e3318ec7..4deb343dae 100644
> --- a/lib/power/power_common.c
> +++ b/lib/power/power_common.c
> @@ -3,13 +3,20 @@
>   */
> 
>  #include <limits.h>
> +#include <stdlib.h>
>  #include <stdio.h>
>  #include <string.h>
> 
> +#include <rte_log.h>
> +#include <rte_string_fns.h>
> +
>  #include "power_common.h"
> 
>  #define POWER_SYSFILE_SCALING_DRIVER   \
>  		"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_driver"
> +#define POWER_SYSFILE_GOVERNOR  \
> +		"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_governor"
> +#define POWER_CONVERT_TO_DECIMAL 10
> 
>  int
>  cpufreq_check_scaling_driver(const char *driver_name) @@ -58,3 +65,142
> @@ cpufreq_check_scaling_driver(const char *driver_name)
>  	 */
>  	return 1;
>  }
> +
> +int
> +open_core_sysfs_file(const char *template, unsigned int core, const char
> *mode,
> +		FILE **f)
> +{
> +	char fullpath[PATH_MAX];
> +	FILE *tmpf;
> +
> +	/* silenced -Wformat-nonliteral here */
> +	snprintf(fullpath, sizeof(fullpath), template, core);
> +	tmpf = fopen(fullpath, mode);
> +	*f = tmpf;
> +	if (tmpf == NULL)
> +		return -1;
> +
> +	return 0;
> +}
> +
> +int
> +read_core_sysfs_u32(FILE *f, uint32_t *val) {
> +	char buf[BUFSIZ];
> +	uint32_t fval;
> +	char *s;
> +
> +	s = fgets(buf, sizeof(buf), f);
> +	if (s == NULL)
> +		return -1;
> +
> +	/* fgets puts null terminator in, but do this just in case */
> +	buf[BUFSIZ - 1] = '\0';
> +
> +	/* strip off any terminating newlines */
> +	*strchrnul(buf, '\n') = '\0';
> +
> +	fval = strtoul(buf, NULL, POWER_CONVERT_TO_DECIMAL);
> +
> +	/* write the value */
> +	*val = fval;
> +
> +	return 0;
> +}
> +
> +int
> +read_core_sysfs_s(FILE *f, char *buf, unsigned int len) {
> +	char *s;
> +
> +	s = fgets(buf, len, f);
> +	if (s == NULL)
> +		return -1;
> +
> +	/* fgets puts null terminator in, but do this just in case */
> +	buf[len - 1] = '\0';
> +
> +	/* strip off any terminating newlines */
> +	*strchrnul(buf, '\n') = '\0';
> +
> +	return 0;
> +}
> +
> +int
> +write_core_sysfs_s(FILE *f, const char *str) {
> +	int ret;
> +
> +	ret = fseek(f, 0, SEEK_SET);
> +	if (ret != 0)
> +		return -1;
> +
> +	ret = fputs(str, f);
> +	if (ret < 0)
> +		return -1;
> +
> +	/* flush the output */
> +	ret = fflush(f);
> +	if (ret != 0)
> +		return -1;
> +
> +	return 0;
> +}
> +
> +/**
> + * It is to check the current scaling governor by reading sys file, and
> +then
> + * set it into 'performance' if it is not by writing the sys file. The
> +original
> + * governor will be saved for rolling back.
> + */
> +int
> +power_set_governor(unsigned int lcore_id, const char *new_governor,
> +		char *orig_governor, size_t orig_governor_len) {
> +	FILE *f_governor = NULL;
> +	int ret = -1;
> +	char buf[BUFSIZ];
> +
> +	open_core_sysfs_file(POWER_SYSFILE_GOVERNOR, lcore_id, "rw+",
> +			&f_governor);
> +	if (f_governor == NULL) {
> +		RTE_LOG(ERR, POWER, "failed to open %s\n",
> +				POWER_SYSFILE_GOVERNOR);
> +		goto out;
> +	}
> +
> +	ret = read_core_sysfs_s(f_governor, buf, sizeof(buf));
> +	if (ret < 0) {
> +		RTE_LOG(ERR, POWER, "Failed to read %s\n",
> +				POWER_SYSFILE_GOVERNOR);
> +		goto out;
> +	}
> +
> +	/* Save the original governor, if it was provided */
> +	if (orig_governor)
> +		rte_strscpy(orig_governor, buf, orig_governor_len);
> +
> +	/* Check if current governor is already what we want */
> +	if (strcmp(buf, new_governor) == 0) {
> +		ret = 0;
> +		POWER_DEBUG_TRACE("Power management governor of
> lcore %u is "
> +				"already %s\n", lcore_id, new_governor);
> +		goto out;
> +	}
> +
> +	/* Write the new governor */
> +	ret = write_core_sysfs_s(f_governor, new_governor);
> +	if (ret < 0) {
> +		RTE_LOG(ERR, POWER, "Failed to write %s\n",
> +				POWER_SYSFILE_GOVERNOR);
> +		goto out;
> +	}
> +
> +	ret = 0;
> +	RTE_LOG(INFO, POWER, "Power management governor of lcore %u
> has been "
> +			"set to '%s' successfully\n", lcore_id, new_governor);
> +out:
> +	if (f_governor != NULL)
> +		fclose(f_governor);
> +
> +	return ret;
> +}
> diff --git a/lib/power/power_common.h b/lib/power/power_common.h
> index fab3ca995a..ef9f5fa855 100644
> --- a/lib/power/power_common.h
> +++ b/lib/power/power_common.h
> @@ -5,9 +5,26 @@
>  #ifndef _POWER_COMMON_H_
>  #define _POWER_COMMON_H_
> 
> +#include <inttypes.h>
> +
>  #define RTE_POWER_INVALID_FREQ_INDEX (~0)
> 
> +
> +#ifdef RTE_LIBRTE_POWER_DEBUG
> +#define POWER_DEBUG_TRACE(fmt, args...) \
> +		RTE_LOG(ERR, POWER, "%s: " fmt, __func__, ## args) #else
> #define
> +POWER_DEBUG_TRACE(fmt, args...) #endif
> +
>  /* check if scaling driver matches one we want */  int
> cpufreq_check_scaling_driver(const char *driver);
> +int power_set_governor(unsigned int lcore_id, const char *new_governor,
> +		char *orig_governor, size_t orig_governor_len); int
> +open_core_sysfs_file(const char *template, unsigned int core,
> +			 const char *mode, FILE **f);
> +int read_core_sysfs_u32(FILE *f, uint32_t *val); int
> +read_core_sysfs_s(FILE *f, char *buf, unsigned int len); int
> +write_core_sysfs_s(FILE *f, const char *str);
> 
>  #endif /* _POWER_COMMON_H_ */
> diff --git a/lib/power/power_pstate_cpufreq.c
> b/lib/power/power_pstate_cpufreq.c
> index 2cfc54acf3..ed10bd193b 100644
> --- a/lib/power/power_pstate_cpufreq.c
> +++ b/lib/power/power_pstate_cpufreq.c
> @@ -21,46 +21,13 @@
>  #include "power_pstate_cpufreq.h"
>  #include "power_common.h"
> 
> -
> -#ifdef RTE_LIBRTE_POWER_DEBUG
> -#define POWER_DEBUG_TRACE(fmt, args...) do { \
> -		RTE_LOG(ERR, POWER, "%s: " fmt, __func__, ## args); \
> -} while (0)
> -#else
> -#define POWER_DEBUG_TRACE(fmt, args...) -#endif
> -
> -#define FOPEN_OR_ERR_RET(f, retval) do { \
> -		if ((f) == NULL) { \
> -			RTE_LOG(ERR, POWER, "File not opened\n"); \
> -			return retval; \
> -		} \
> -} while (0)
> -
> -#define FOPS_OR_NULL_GOTO(ret, label) do { \
> -		if ((ret) == NULL) { \
> -			RTE_LOG(ERR, POWER, "fgets returns nothing\n"); \
> -			goto label; \
> -		} \
> -} while (0)
> -
> -#define FOPS_OR_ERR_GOTO(ret, label) do { \
> -		if ((ret) < 0) { \
> -			RTE_LOG(ERR, POWER, "File operations failed\n"); \
> -			goto label; \
> -		} \
> -} while (0)
> -
>  /* macros used for rounding frequency to nearest 100000 */  #define
> FREQ_ROUNDING_DELTA 50000  #define ROUND_FREQ_TO_N_100000
> 100000
> 
> -#define POWER_CONVERT_TO_DECIMAL 10
>  #define BUS_FREQ     100000
> 
>  #define POWER_GOVERNOR_PERF "performance"
> -#define POWER_SYSFILE_GOVERNOR  \
> -		"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_governor"
>  #define POWER_SYSFILE_MAX_FREQ \
> 
> 	"/sys/devices/system/cpu/cpu%u/cpufreq/scaling_max_freq"
>  #define POWER_SYSFILE_MIN_FREQ  \
> @@ -154,91 +121,78 @@ out:	close(fd);
>  static int
>  power_init_for_setting_freq(struct pstate_power_info *pi)  {
> -	FILE *f_min, *f_max, *f_base = NULL, *f_base_max;
> -	char fullpath_min[PATH_MAX];
> -	char fullpath_max[PATH_MAX];
> -	char fullpath_base[PATH_MAX];
> -	char fullpath_base_max[PATH_MAX];
> -	char buf_base[BUFSIZ];
> -	char *s_base;
> -	char *s_base_max;
> -	uint32_t base_ratio = 0;
> -	uint32_t base_max_ratio = 0;
> -	uint64_t max_non_turbo = 0;
> -	int  ret_val = 0;
> -
> -	snprintf(fullpath_base_max,
> -			sizeof(fullpath_base_max),
> -			POWER_SYSFILE_BASE_MAX_FREQ,
> -			pi->lcore_id);
> -	f_base_max = fopen(fullpath_base_max, "r");
> -	FOPEN_OR_ERR_RET(f_base_max, -1);
> -	if (f_base_max != NULL) {
> -		s_base_max = fgets(buf_base, sizeof(buf_base),
> f_base_max);
> -
> -		/* close the file unconditionally */
> -		fclose(f_base_max);
> -		f_base_max = NULL;
> -
> -		FOPS_OR_NULL_GOTO(s_base_max, out);
> -
> -		buf_base[BUFSIZ-1] = '\0';
> -		if (strlen(buf_base))
> -			/* Strip off terminating '\n' */
> -			strtok(buf_base, "\n");
> -
> -		base_max_ratio =
> -			strtoul(buf_base, NULL,
> POWER_CONVERT_TO_DECIMAL)
> -				/ BUS_FREQ;
> +	FILE *f_base = NULL, *f_base_max = NULL, *f_min = NULL, *f_max =
> NULL;
> +	uint32_t base_ratio, base_max_ratio;
> +	uint64_t max_non_turbo;
> +	int ret;
> +
> +	/* open all files we expect to have open */
> +	open_core_sysfs_file(POWER_SYSFILE_BASE_MAX_FREQ, pi-
> >lcore_id, "r",
> +			&f_base_max);
> +	if (f_base_max == NULL) {
> +		RTE_LOG(ERR, POWER, "failed to open %s\n",
> +				POWER_SYSFILE_BASE_MAX_FREQ);
> +		goto err;
> +	}
> +
> +	open_core_sysfs_file(POWER_SYSFILE_MIN_FREQ, pi->lcore_id,
> "rw+",
> +			&f_min);
> +	if (f_min == NULL) {
> +		RTE_LOG(ERR, POWER, "failed to open %s\n",
> +				POWER_SYSFILE_MIN_FREQ);
> +		goto err;
> +	}
> +
> +	open_core_sysfs_file(POWER_SYSFILE_MAX_FREQ, pi->lcore_id,
> "rw+",
> +			&f_max);
> +	if (f_max == NULL) {
> +		RTE_LOG(ERR, POWER, "failed to open %s\n",
> +				POWER_SYSFILE_MAX_FREQ);
> +		goto err;
> +	}
> +
> +	open_core_sysfs_file(POWER_SYSFILE_BASE_FREQ, pi->lcore_id, "r",
> +			&f_base);
> +	/* base ratio file may not exist in some kernels, so no error check */
> +
> +	/* read base max ratio */
> +	ret = read_core_sysfs_u32(f_base_max, &base_max_ratio);
> +	if (ret < 0) {
> +		RTE_LOG(ERR, POWER, "Failed to read %s\n",
> +				POWER_SYSFILE_BASE_MAX_FREQ);
> +		goto err;
> +	}
> +
> +	/* base ratio may not exist */
> +	if (f_base != NULL) {
> +		ret = read_core_sysfs_u32(f_base, &base_ratio);
> +		if (ret < 0) {
> +			RTE_LOG(ERR, POWER, "Failed to read %s\n",
> +					POWER_SYSFILE_BASE_FREQ);
> +			goto err;
> +		}
> +	} else {
> +		base_ratio = 0;
>  	}
> 
> -	snprintf(fullpath_min, sizeof(fullpath_min),
> POWER_SYSFILE_MIN_FREQ,
> -			pi->lcore_id);
> -	f_min = fopen(fullpath_min, "rw+");
> -	FOPEN_OR_ERR_RET(f_min, -1);
> +	/* Add MSR read to detect turbo status */
> +	if (power_rdmsr(PLATFORM_INFO, &max_non_turbo, pi->lcore_id) <
> 0)
> +		goto err;
> +	/* no errors after this point */
> 
> -	snprintf(fullpath_max, sizeof(fullpath_max),
> POWER_SYSFILE_MAX_FREQ,
> -			pi->lcore_id);
> -	f_max = fopen(fullpath_max, "rw+");
> -	if (f_max == NULL)
> -		fclose(f_min);
> -	FOPEN_OR_ERR_RET(f_max, -1);
> +	/* convert ratios to bins */
> +	base_max_ratio /= BUS_FREQ;
> +	base_ratio /= BUS_FREQ;
> 
> +	/* assign file handles */
>  	pi->f_cur_min = f_min;
>  	pi->f_cur_max = f_max;
> 
> -	snprintf(fullpath_base, sizeof(fullpath_base),
> POWER_SYSFILE_BASE_FREQ,
> -			pi->lcore_id);
> -
> -	f_base = fopen(fullpath_base, "r");
> -	if (f_base == NULL) {
> -		/* No sysfs base_frequency, that's OK, continue without */
> -		base_ratio = 0;
> -	} else {
> -		s_base = fgets(buf_base, sizeof(buf_base), f_base);
> -		FOPS_OR_NULL_GOTO(s_base, out);
> -
> -		buf_base[BUFSIZ-1] = '\0';
> -		if (strlen(buf_base))
> -			/* Strip off terminating '\n' */
> -			strtok(buf_base, "\n");
> -
> -		base_ratio = strtoul(buf_base, NULL,
> POWER_CONVERT_TO_DECIMAL)
> -				/ BUS_FREQ;
> -	}
> -
> -	/* Add MSR read to detect turbo status */
> -
> -	if (power_rdmsr(PLATFORM_INFO, &max_non_turbo, pi->lcore_id) <
> 0) {
> -		ret_val = -1;
> -		goto out;
> -	}
> -
>  	max_non_turbo =
> (max_non_turbo&NON_TURBO_MASK)>>NON_TURBO_OFFSET;
> 
>  	POWER_DEBUG_TRACE("no turbo perf %"PRIu64"\n",
> max_non_turbo);
> 
> -	pi->non_turbo_max_ratio = max_non_turbo;
> +	pi->non_turbo_max_ratio = (uint32_t)max_non_turbo;
> 
>  	/*
>  	 * If base_frequency is reported as greater than the maximum @@ -
> 264,7 +218,20 @@ power_init_for_setting_freq(struct pstate_power_info
> *pi)
>  out:
>  	if (f_base != NULL)
>  		fclose(f_base);
> -	return ret_val;
> +	fclose(f_base_max);
> +	/* f_min and f_max are stored, no need to close */
> +	return 0;
> +
> +err:
> +	if (f_base != NULL)
> +		fclose(f_base);
> +	if (f_base_max != NULL)
> +		fclose(f_base_max);
> +	if (f_min != NULL)
> +		fclose(f_min);
> +	if (f_max != NULL)
> +		fclose(f_max);
> +	return -1;
>  }
> 
>  static int
> @@ -369,53 +336,8 @@ set_freq_internal(struct pstate_power_info *pi,
> uint32_t idx)  static int  power_set_governor_performance(struct
> pstate_power_info *pi)  {
> -	FILE *f;
> -	int ret = -1;
> -	char buf[BUFSIZ];
> -	char fullpath[PATH_MAX];
> -	char *s;
> -	int val;
> -
> -	snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_GOVERNOR,
> -			pi->lcore_id);
> -	f = fopen(fullpath, "rw+");
> -	FOPEN_OR_ERR_RET(f, ret);
> -
> -	s = fgets(buf, sizeof(buf), f);
> -	FOPS_OR_NULL_GOTO(s, out);
> -	/* Strip off terminating '\n' */
> -	strtok(buf, "\n");
> -
> -	/* Save the original governor */
> -	rte_strscpy(pi->governor_ori, buf, sizeof(pi->governor_ori));
> -
> -	/* Check if current governor is performance */
> -	if (strncmp(buf, POWER_GOVERNOR_PERF,
> -			sizeof(POWER_GOVERNOR_PERF)) == 0) {
> -		ret = 0;
> -		POWER_DEBUG_TRACE("Power management governor of
> lcore %u is "
> -				"already performance\n", pi->lcore_id);
> -		goto out;
> -	}
> -
> -	/* Write 'performance' to the governor */
> -	val = fseek(f, 0, SEEK_SET);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	val = fputs(POWER_GOVERNOR_PERF, f);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	/* We need to flush to see if the fputs succeeds */
> -	val = fflush(f);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	ret = 0;
> -	RTE_LOG(INFO, POWER, "Power management governor of lcore %u
> has been "
> -			"set to performance successfully\n", pi->lcore_id);
> -out:
> -	fclose(f);
> -
> -	return ret;
> +	return power_set_governor(pi->lcore_id, POWER_GOVERNOR_PERF,
> +			pi->governor_ori, sizeof(pi->governor_ori));
>  }
> 
>  /**
> @@ -425,45 +347,7 @@ power_set_governor_performance(struct
> pstate_power_info *pi)  static int  power_set_governor_original(struct
> pstate_power_info *pi)  {
> -	FILE *f;
> -	int ret = -1;
> -	char buf[BUFSIZ];
> -	char fullpath[PATH_MAX];
> -	char *s;
> -	int val;
> -
> -	snprintf(fullpath, sizeof(fullpath), POWER_SYSFILE_GOVERNOR,
> -			pi->lcore_id);
> -	f = fopen(fullpath, "rw+");
> -	FOPEN_OR_ERR_RET(f, ret);
> -
> -	s = fgets(buf, sizeof(buf), f);
> -	FOPS_OR_NULL_GOTO(s, out);
> -
> -	/* Check if the governor to be set is the same as current */
> -	if (strncmp(buf, pi->governor_ori, sizeof(pi->governor_ori)) == 0) {
> -		ret = 0;
> -		POWER_DEBUG_TRACE("Power management governor of
> lcore %u "
> -				"has already been set to %s\n",
> -				pi->lcore_id, pi->governor_ori);
> -		goto out;
> -	}
> -
> -	/* Write back the original governor */
> -	val = fseek(f, 0, SEEK_SET);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	val = fputs(pi->governor_ori, f);
> -	FOPS_OR_ERR_GOTO(val, out);
> -
> -	ret = 0;
> -	RTE_LOG(INFO, POWER, "Power management governor of lcore %u "
> -			"has been set back to %s successfully\n",
> -			pi->lcore_id, pi->governor_ori);
> -out:
> -	fclose(f);
> -
> -	return ret;
> +	return power_set_governor(pi->lcore_id, pi->governor_ori, NULL, 0);
>  }
> 
>  /**
> @@ -473,51 +357,42 @@ power_set_governor_original(struct
> pstate_power_info *pi)  static int  power_get_available_freqs(struct
> pstate_power_info *pi)  {
> -	FILE *f_min, *f_max;
> +	FILE *f_min = NULL, *f_max = NULL;
>  	int ret = -1;
> -	char *p_min, *p_max;
> -	char buf_min[BUFSIZ];
> -	char buf_max[BUFSIZ];
> -	char fullpath_min[PATH_MAX];
> -	char fullpath_max[PATH_MAX];
> -	char *s_min, *s_max;
>  	uint32_t sys_min_freq = 0, sys_max_freq = 0, base_max_freq = 0;
>  	uint32_t i, num_freqs = 0;
> 
> -	snprintf(fullpath_max, sizeof(fullpath_max),
> -			POWER_SYSFILE_BASE_MAX_FREQ,
> -			pi->lcore_id);
> -	snprintf(fullpath_min, sizeof(fullpath_min),
> -			POWER_SYSFILE_BASE_MIN_FREQ,
> -			pi->lcore_id);
> -
> -	f_min = fopen(fullpath_min, "r");
> -	FOPEN_OR_ERR_RET(f_min, ret);
> -
> -	f_max = fopen(fullpath_max, "r");
> -	if (f_max == NULL)
> -		fclose(f_min);
> -
> -	FOPEN_OR_ERR_RET(f_max, ret);
> -
> -	s_min = fgets(buf_min, sizeof(buf_min), f_min);
> -	FOPS_OR_NULL_GOTO(s_min, out);
> -
> -	s_max = fgets(buf_max, sizeof(buf_max), f_max);
> -	FOPS_OR_NULL_GOTO(s_max, out);
> -
> +	/* open all files */
> +	open_core_sysfs_file(POWER_SYSFILE_BASE_MAX_FREQ, pi-
> >lcore_id, "r",
> +			&f_max);
> +	if (f_max == NULL) {
> +		RTE_LOG(ERR, POWER, "failed to open %s\n",
> +				POWER_SYSFILE_BASE_MAX_FREQ);
> +		goto out;
> +	}
> 
> -	/* Strip the line break if there is */
> -	p_min = strchr(buf_min, '\n');
> -	if (p_min != NULL)
> -		*p_min = 0;
> +	open_core_sysfs_file(POWER_SYSFILE_BASE_MIN_FREQ, pi->lcore_id,
> "r",
> +			     &f_min);
> +	if (f_min == NULL) {
> +		RTE_LOG(ERR, POWER, "failed to open %s\n",
> +				POWER_SYSFILE_BASE_MIN_FREQ);
> +		goto out;
> +	}
> 
> -	p_max = strchr(buf_max, '\n');
> -	if (p_max != NULL)
> -		*p_max = 0;
> +	/* read base ratios */
> +	ret = read_core_sysfs_u32(f_max, &sys_max_freq);
> +	if (ret < 0) {
> +		RTE_LOG(ERR, POWER, "Failed to read %s\n",
> +				POWER_SYSFILE_BASE_MAX_FREQ);
> +		goto out;
> +	}
> 
> -	sys_min_freq = strtoul(buf_min, &p_min,
> POWER_CONVERT_TO_DECIMAL);
> -	sys_max_freq = strtoul(buf_max, &p_max,
> POWER_CONVERT_TO_DECIMAL);
> +	ret = read_core_sysfs_u32(f_min, &sys_min_freq);
> +	if (ret < 0) {
> +		RTE_LOG(ERR, POWER, "Failed to read %s\n",
> +				POWER_SYSFILE_BASE_MIN_FREQ);
> +		goto out;
> +	}
> 
>  	if (sys_max_freq < sys_min_freq)
>  		goto out;
> @@ -576,27 +451,22 @@ power_get_cur_idx(struct pstate_power_info *pi)
> {
>  	FILE *f_cur;
>  	int ret = -1;
> -	char *p_cur;
> -	char buf_cur[BUFSIZ];
> -	char fullpath_cur[PATH_MAX];
> -	char *s_cur;
>  	uint32_t sys_cur_freq = 0;
>  	unsigned int i;
> 
> -	snprintf(fullpath_cur, sizeof(fullpath_cur),
> -			POWER_SYSFILE_CUR_FREQ,
> -			pi->lcore_id);
> -	f_cur = fopen(fullpath_cur, "r");
> -	FOPEN_OR_ERR_RET(f_cur, ret);
> -
> -	/* initialize the cur_idx to matching current frequency freq index */
> -	s_cur = fgets(buf_cur, sizeof(buf_cur), f_cur);
> -	FOPS_OR_NULL_GOTO(s_cur, fail);
> +	open_core_sysfs_file(POWER_SYSFILE_CUR_FREQ, pi->lcore_id, "r",
> &f_cur);
> +	if (f_cur == NULL) {
> +		RTE_LOG(ERR, POWER, "failed to open %s\n",
> +				POWER_SYSFILE_CUR_FREQ);
> +		goto fail;
> +	}
> 
> -	p_cur = strchr(buf_cur, '\n');
> -	if (p_cur != NULL)
> -		*p_cur = 0;
> -	sys_cur_freq = strtoul(buf_cur, &p_cur,
> POWER_CONVERT_TO_DECIMAL);
> +	ret = read_core_sysfs_u32(f_cur, &sys_cur_freq);
> +	if (ret < 0) {
> +		RTE_LOG(ERR, POWER, "Failed to read %s\n",
> +				POWER_SYSFILE_CUR_FREQ);
> +		goto fail;
> +	}
> 
>  	/* convert the frequency to nearest 100000 value
>  	 * Ex: if sys_cur_freq=1396789 then freq_conv=1400000 @@ -615,10
> +485,10 @@ power_get_cur_idx(struct pstate_power_info *pi)
>  		}
>  	}
> 
> -	fclose(f_cur);
> -	return 0;
> +	ret = 0;
>  fail:
> -	fclose(f_cur);
> +	if (f_cur != NULL)
> +		fclose(f_cur);
>  	return ret;
>  }
> 
> --
> 2.17.1
  

On Wed, Jun 23, 2021 at 2:04 PM David Hunt <david.hunt@intel.com> wrote:
>
> From: Anatoly Burakov <anatoly.burakov@intel.com>
>
> Currently, ACPI and PSTATE modes have lots of code duplication,
> confusing logic, and a bunch of other issues that can, and have, led to
> various bugs and resource leaks.
>
> This commit factors out the common parts of sysfs reading/writing for
> ACPI and PSTATE drivers.
>
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> Signed-off-by: David Hunt <david.hunt@intel.com>
>
> ---
> changes in v5
> * fixed bugs raised by Richael Zhuang in review - open file rw+, etc.
> * removed FOPS* and FOPEN* macros, which contained control statements.
> * fixed some checkpatch warnings.
> changes in v6
> * fixed check of fputs return, negative on error.
> ---
>  lib/power/meson.build            |   7 +
>  lib/power/power_acpi_cpufreq.c   | 192 ++++------------
>  lib/power/power_common.c         | 146 ++++++++++++
>  lib/power/power_common.h         |  17 ++
>  lib/power/power_pstate_cpufreq.c | 374 ++++++++++---------------------
>  5 files changed, 335 insertions(+), 401 deletions(-)
>
> diff --git a/lib/power/meson.build b/lib/power/meson.build
> index c1097d32f1..74c5f3a294 100644
> --- a/lib/power/meson.build
> +++ b/lib/power/meson.build
> @@ -5,6 +5,13 @@ if not is_linux
>      build = false
>      reason = 'only supported on Linux'
>  endif
> +
> +# we do some snprintf magic so silence format-nonliteral
> +flag_nonliteral = '-Wno-format-nonliteral'
> +if cc.has_argument(flag_nonliteral)
> +       cflags += flag_nonliteral
> +endif
> +

This can be removed with __rte_format_printf tag + API change below.


>  sources = files(
>          'guest_channel.c',
>          'power_acpi_cpufreq.c',

[snip]

> diff --git a/lib/power/power_common.c b/lib/power/power_common.c
> index 67e3318ec7..4deb343dae 100644
> --- a/lib/power/power_common.c
> +++ b/lib/power/power_common.c
> @@ -3,13 +3,20 @@
>   */
>
>  #include <limits.h>
> +#include <stdlib.h>
>  #include <stdio.h>
>  #include <string.h>
>
> +#include <rte_log.h>
> +#include <rte_string_fns.h>
> +
>  #include "power_common.h"
>
>  #define POWER_SYSFILE_SCALING_DRIVER   \
>                 "/sys/devices/system/cpu/cpu%u/cpufreq/scaling_driver"
> +#define POWER_SYSFILE_GOVERNOR  \
> +               "/sys/devices/system/cpu/cpu%u/cpufreq/scaling_governor"
> +#define POWER_CONVERT_TO_DECIMAL 10
>
>  int
>  cpufreq_check_scaling_driver(const char *driver_name)
> @@ -58,3 +65,142 @@ cpufreq_check_scaling_driver(const char *driver_name)
>          */
>         return 1;
>  }

cpufreq_check_scaling_driver can use open_core_sysfs_file, right?


> +
> +int
> +open_core_sysfs_file(const char *template, unsigned int core, const char *mode,
> +               FILE **f)
> +{
> +       char fullpath[PATH_MAX];
> +       FILE *tmpf;
> +
> +       /* silenced -Wformat-nonliteral here */
> +       snprintf(fullpath, sizeof(fullpath), template, core);
> +       tmpf = fopen(fullpath, mode);
> +       *f = tmpf;
> +       if (tmpf == NULL)
> +               return -1;
> +
> +       return 0;
> +}


@@ -67,14 +67,15 @@ cpufreq_check_scaling_driver(const char *driver_name)
 }

 int
-open_core_sysfs_file(const char *template, unsigned int core, const char *mode,
-               FILE **f)
+open_core_sysfs_file(FILE **f, const char *mode, const char *format, ...)
 {
        char fullpath[PATH_MAX];
+       va_list ap;
        FILE *tmpf;

-       /* silenced -Wformat-nonliteral here */
-       snprintf(fullpath, sizeof(fullpath), template, core);
+       va_start(ap, format);
+       vsnprintf(fullpath, sizeof(fullpath), format, ap);
+       va_end(ap);
        tmpf = fopen(fullpath, mode);
        *f = tmpf;
        if (tmpf == NULL)



With declaration in .h as:

@@ -7,6 +7,8 @@

 #include <inttypes.h>

+#include <rte_common.h>
+
 #define RTE_POWER_INVALID_FREQ_INDEX (~0)


@@ -21,8 +23,8 @@
 int cpufreq_check_scaling_driver(const char *driver);
 int power_set_governor(unsigned int lcore_id, const char *new_governor,
                char *orig_governor, size_t orig_governor_len);
-int open_core_sysfs_file(const char *template, unsigned int core,
-                        const char *mode, FILE **f);
+int open_core_sysfs_file(FILE **f, const char *mode, const char *format, ...)
+               __rte_format_printf(3, 4);
 int read_core_sysfs_u32(FILE *f, uint32_t *val);
 int read_core_sysfs_s(FILE *f, char *buf, unsigned int len);
 int write_core_sysfs_s(FILE *f, const char *str);


This leaves the possibility to use any kind of formats.
And to be honest, I did not manage to make gcc happy otherwise (even
when passing __rte_format_printf(3, 0)).
  

On 8/7/2021 1:49 PM, David Marchand wrote:
> On Wed, Jun 23, 2021 at 2:04 PM David Hunt <david.hunt@intel.com> wrote:
>> From: Anatoly Burakov <anatoly.burakov@intel.com>
>>
>> Currently, ACPI and PSTATE modes have lots of code duplication,
>> confusing logic, and a bunch of other issues that can, and have, led to
>> various bugs and resource leaks.
>>
>> This commit factors out the common parts of sysfs reading/writing for
>> ACPI and PSTATE drivers.
>>
>> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
>> Signed-off-by: David Hunt <david.hunt@intel.com>
>>
>> ---
>> changes in v5
>> * fixed bugs raised by Richael Zhuang in review - open file rw+, etc.
>> * removed FOPS* and FOPEN* macros, which contained control statements.
>> * fixed some checkpatch warnings.
>> changes in v6
>> * fixed check of fputs return, negative on error.
>> ---
>>   lib/power/meson.build            |   7 +
>>   lib/power/power_acpi_cpufreq.c   | 192 ++++------------
>>   lib/power/power_common.c         | 146 ++++++++++++
>>   lib/power/power_common.h         |  17 ++
>>   lib/power/power_pstate_cpufreq.c | 374 ++++++++++---------------------
>>   5 files changed, 335 insertions(+), 401 deletions(-)
>>
>> diff --git a/lib/power/meson.build b/lib/power/meson.build
>> index c1097d32f1..74c5f3a294 100644
>> --- a/lib/power/meson.build
>> +++ b/lib/power/meson.build
>> @@ -5,6 +5,13 @@ if not is_linux
>>       build = false
>>       reason = 'only supported on Linux'
>>   endif
>> +
>> +# we do some snprintf magic so silence format-nonliteral
>> +flag_nonliteral = '-Wno-format-nonliteral'
>> +if cc.has_argument(flag_nonliteral)
>> +       cflags += flag_nonliteral
>> +endif
>> +
> This can be removed with __rte_format_printf tag + API change below.
>
>
>>   sources = files(
>>           'guest_channel.c',
>>           'power_acpi_cpufreq.c',
> [snip]
>
>> diff --git a/lib/power/power_common.c b/lib/power/power_common.c
>> index 67e3318ec7..4deb343dae 100644
>> --- a/lib/power/power_common.c
>> +++ b/lib/power/power_common.c
>> @@ -3,13 +3,20 @@
>>    */
>>
>>   #include <limits.h>
>> +#include <stdlib.h>
>>   #include <stdio.h>
>>   #include <string.h>
>>
>> +#include <rte_log.h>
>> +#include <rte_string_fns.h>
>> +
>>   #include "power_common.h"
>>
>>   #define POWER_SYSFILE_SCALING_DRIVER   \
>>                  "/sys/devices/system/cpu/cpu%u/cpufreq/scaling_driver"
>> +#define POWER_SYSFILE_GOVERNOR  \
>> +               "/sys/devices/system/cpu/cpu%u/cpufreq/scaling_governor"
>> +#define POWER_CONVERT_TO_DECIMAL 10
>>
>>   int
>>   cpufreq_check_scaling_driver(const char *driver_name)
>> @@ -58,3 +65,142 @@ cpufreq_check_scaling_driver(const char *driver_name)
>>           */
>>          return 1;
>>   }
> cpufreq_check_scaling_driver can use open_core_sysfs_file, right?
>
>
>> +
>> +int
>> +open_core_sysfs_file(const char *template, unsigned int core, const char *mode,
>> +               FILE **f)
>> +{
>> +       char fullpath[PATH_MAX];
>> +       FILE *tmpf;
>> +
>> +       /* silenced -Wformat-nonliteral here */
>> +       snprintf(fullpath, sizeof(fullpath), template, core);
>> +       tmpf = fopen(fullpath, mode);
>> +       *f = tmpf;
>> +       if (tmpf == NULL)
>> +               return -1;
>> +
>> +       return 0;
>> +}
>
> @@ -67,14 +67,15 @@ cpufreq_check_scaling_driver(const char *driver_name)
>   }
>
>   int
> -open_core_sysfs_file(const char *template, unsigned int core, const char *mode,
> -               FILE **f)
> +open_core_sysfs_file(FILE **f, const char *mode, const char *format, ...)
>   {
>          char fullpath[PATH_MAX];
> +       va_list ap;
>          FILE *tmpf;
>
> -       /* silenced -Wformat-nonliteral here */
> -       snprintf(fullpath, sizeof(fullpath), template, core);
> +       va_start(ap, format);
> +       vsnprintf(fullpath, sizeof(fullpath), format, ap);
> +       va_end(ap);
>          tmpf = fopen(fullpath, mode);
>          *f = tmpf;
>          if (tmpf == NULL)
>
>
>
> With declaration in .h as:
>
> @@ -7,6 +7,8 @@
>
>   #include <inttypes.h>
>
> +#include <rte_common.h>
> +
>   #define RTE_POWER_INVALID_FREQ_INDEX (~0)
>
>
> @@ -21,8 +23,8 @@
>   int cpufreq_check_scaling_driver(const char *driver);
>   int power_set_governor(unsigned int lcore_id, const char *new_governor,
>                  char *orig_governor, size_t orig_governor_len);
> -int open_core_sysfs_file(const char *template, unsigned int core,
> -                        const char *mode, FILE **f);
> +int open_core_sysfs_file(FILE **f, const char *mode, const char *format, ...)
> +               __rte_format_printf(3, 4);
>   int read_core_sysfs_u32(FILE *f, uint32_t *val);
>   int read_core_sysfs_s(FILE *f, char *buf, unsigned int len);
>   int write_core_sysfs_s(FILE *f, const char *str);
>
>
> This leaves the possibility to use any kind of formats.
> And to be honest, I did not manage to make gcc happy otherwise (even
> when passing __rte_format_printf(3, 0)).


Thanks, David, good suggestions.  I'll make those changes and respin.

Rgds,
Dave.


>