Commit 1205b688 authored by Fenghua Yu's avatar Fenghua Yu Committed by Shuah Khan
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selftests/resctrl: Fix checking for < 0 for unsigned values 



Dan reported following static checker warnings

tools/testing/selftests/resctrl/resctrl_val.c:545 measure_vals()
warn: 'bw_imc' unsigned <= 0

tools/testing/selftests/resctrl/resctrl_val.c:549 measure_vals()
warn: 'bw_resc_end' unsigned <= 0

These warnings are reported because
1. measure_vals() declares 'bw_imc' and 'bw_resc_end' as unsigned long
   variables
2. Return value of get_mem_bw_imc() and get_mem_bw_resctrl() are assigned
   to 'bw_imc' and 'bw_resc_end' respectively
3. The returned values are checked for <= 0 to see if the calls failed

Checking for < 0 for an unsigned value doesn't make any sense.

Fix this issue by changing the implementation of get_mem_bw_imc() and
get_mem_bw_resctrl() such that they now accept reference to a variable
and set the variable appropriately upon success and return 0, else return
< 0 on error.

Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Tested-by: default avatarBabu Moger <babu.moger@amd.com>
Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
parent d81343b5

tools/testing/selftests/resctrl/resctrl_val.c

+23 −18
Original line number Diff line number Diff line
@@ -300,9 +300,9 @@ static int initialize_mem_bw_imc(void) 
 * Memory B/W utilized by a process on a socket can be calculated using

 * iMC counters. Perf events are used to read these counters.

 *

 * Return: >= 0 on success. < 0 on failure.

 * Return: = 0 on success. < 0 on failure.

 */

static float get_mem_bw_imc(int cpu_no, char *bw_report)

static int get_mem_bw_imc(int cpu_no, char *bw_report, float *bw_imc)

{

	float reads, writes, of_mul_read, of_mul_write;

	int imc, j, ret;
@@ -373,13 +373,18 @@ static float get_mem_bw_imc(int cpu_no, char *bw_report) 
		close(imc_counters_config[imc][WRITE].fd);

	}



	if (strcmp(bw_report, "reads") == 0)

		return reads;

	if (strcmp(bw_report, "reads") == 0) {

		*bw_imc = reads;

		return 0;

	}



	if (strcmp(bw_report, "writes") == 0)

		return writes;

	if (strcmp(bw_report, "writes") == 0) {

		*bw_imc = writes;

		return 0;

	}



	return (reads + writes);

	*bw_imc = reads + writes;

	return 0;

}



void set_mbm_path(const char *ctrlgrp, const char *mongrp, int resource_id)
@@ -438,9 +443,8 @@ static void initialize_mem_bw_resctrl(const char *ctrlgrp, const char *mongrp, 
 * 1. If con_mon grp is given, then read from it

 * 2. If con_mon grp is not given, then read from root con_mon grp

 */

static unsigned long get_mem_bw_resctrl(void)

static int get_mem_bw_resctrl(unsigned long *mbm_total)

{

	unsigned long mbm_total = 0;

	FILE *fp;



	fp = fopen(mbm_total_path, "r");
@@ -449,7 +453,7 @@ static unsigned long get_mem_bw_resctrl(void) 


		return -1;

	}

	if (fscanf(fp, "%lu", &mbm_total) <= 0) {

	if (fscanf(fp, "%lu", mbm_total) <= 0) {

		perror("Could not get mbm local bytes");

		fclose(fp);
@@ -457,7 +461,7 @@ static unsigned long get_mem_bw_resctrl(void) 
	}

	fclose(fp);



	return mbm_total;

	return 0;

}



pid_t bm_pid, ppid;
@@ -549,7 +553,8 @@ static void initialize_llc_occu_resctrl(const char *ctrlgrp, const char *mongrp, 
static int

measure_vals(struct resctrl_val_param *param, unsigned long *bw_resc_start)

{

	unsigned long bw_imc, bw_resc, bw_resc_end;

	unsigned long bw_resc, bw_resc_end;

	float bw_imc;

	int ret;



	/*
@@ -559,13 +564,13 @@ measure_vals(struct resctrl_val_param *param, unsigned long *bw_resc_start) 
	 * Compare the two values to validate resctrl value.

	 * It takes 1sec to measure the data.

	 */

	bw_imc = get_mem_bw_imc(param->cpu_no, param->bw_report);

	if (bw_imc <= 0)

		return bw_imc;

	ret = get_mem_bw_imc(param->cpu_no, param->bw_report, &bw_imc);

	if (ret < 0)

		return ret;



	bw_resc_end = get_mem_bw_resctrl();

	if (bw_resc_end <= 0)

		return bw_resc_end;

	ret = get_mem_bw_resctrl(&bw_resc_end);

	if (ret < 0)

		return ret;



	bw_resc = (bw_resc_end - *bw_resc_start) / MB;

	ret = print_results_bw(param->filename, bm_pid, bw_imc, bw_resc);