igt/pm_rpm: Use libc 'ftw' rather than opencoding our own filetree walk

By using ftw, we avoid the issue of having to handle directory recursion
ourselves and can focus on the test of checking the reading a
sysfs/debugfs does not break runtime suspend. In the process, disregard
errors when opening the individual files as they may fail for other
reasons.

v2: Bracket the file open/close with the wait_for_suspended() tests.
Whilst the fd is open, it may be keeping the device awake, e.g.
i915_forcewake_user.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Jari Tahvanainen <jari.tahvanainen@intel.com>

1 files changed, 40 insertions, 51 deletions

diff --git a/tests/pm_rpm.c b/tests/pm_rpm.c
index 9e8cf79b..fb26e384 100644
--- a/tests/pm_rpm.c
+++ b/tests/pm_rpm.c
@@ -25,13 +25,13 @@
  *
  */
 
-#include "igt.h"
-#include "igt_kmod.h"
-#include "igt_sysfs.h"
+#include "config.h"
+
 #include <stdio.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include <string.h>
+#include <ftw.h>
 
 #include <unistd.h>
 #include <fcntl.h>
@@ -45,6 +45,10 @@
 
 #include <drm.h>
 
+#include "igt.h"
+#include "igt_kmod.h"
+#include "igt_sysfs.h"
+#include "igt_debugfs.h"
 
 #define MSR_PC8_RES	0x630
 #define MSR_PC9_RES	0x631
@@ -830,55 +834,40 @@ static void i2c_subtest(void)
 	enable_one_screen(&ms_data);
 }
 
-static void read_full_file(int fd, const char *name)
-{
-	int rc;
-	char buf[128];
-
-	igt_assert_f(wait_for_suspended(), "File: %s\n", name);
-
-	do {
-		rc = read(fd, buf, ARRAY_SIZE(buf));
-	} while (rc == ARRAY_SIZE(buf));
-
-	igt_assert_f(wait_for_suspended(), "File: %s\n", name);
-}
-
-static void read_files_from_dir(int path, int level)
+static int read_entry(const char *filepath,
+		      const struct stat *info,
+		      const int typeflag,
+		      struct FTW *pathinfo)
 {
-	DIR *dir;
-	struct dirent *dirent;
+	char buf[4096];
+	int fd;
 	int rc;
 
-	dir = fdopendir(path);
-	igt_assert(dir);
-
-	igt_assert_lt(level, 128);
-
-	while ((dirent = readdir(dir))) {
-		struct stat stat_buf;
-		int de;
+	igt_assert_f(wait_for_suspended(), "Before opening: %s (%s)\n",
+		     filepath + pathinfo->base, filepath);
 
-		if (strcmp(dirent->d_name, ".") == 0)
-			continue;
-		if (strcmp(dirent->d_name, "..") == 0)
-			continue;
-
-		de = openat(path, dirent->d_name, O_RDONLY);
+	fd = open(filepath, O_RDONLY | O_NONBLOCK);
+	if (fd < 0) {
+		igt_debug("Failed to open '%s': %m\n", filepath);
+		return 0;
+	}
 
-		rc = fstat(de, &stat_buf);
-		igt_assert_eq(rc, 0);
+	do {
+		rc = read(fd, buf, sizeof(buf));
+	} while (rc == sizeof(buf));
 
-		if (S_ISDIR(stat_buf.st_mode))
-			read_files_from_dir(de, level + 1);
+	close(fd);
 
-		if (S_ISREG(stat_buf.st_mode))
-			read_full_file(de, dirent->d_name);
+	igt_assert_f(wait_for_suspended(), "After closing: %s (%s)\n",
+		     filepath + pathinfo->base, filepath);
 
-		close(de);
-	}
+	return 0;
+}
 
-	closedir(dir);
+static void walk_fs(char *path)
+{
+	disable_all_screens_and_wait(&ms_data);
+	nftw(path, read_entry, 20, FTW_PHYS | FTW_MOUNT);
 }
 
 /* This test will probably pass, with a small chance of hanging the machine in
@@ -886,21 +875,21 @@ static void read_files_from_dir(int path, int level)
  * errors, so a "pass" here should be confirmed by a check on dmesg. */
 static void debugfs_read_subtest(void)
 {
-	disable_all_screens_and_wait(&ms_data);
+	char path[256];
 
-	read_files_from_dir(debugfs, 0);
+	igt_require_f(igt_debugfs_path(drm_fd, path, sizeof(path)),
+		      "Can't find the debugfs directory\n");
+	walk_fs(path);
 }
 
 /* Read the comment on debugfs_read_subtest(). */
 static void sysfs_read_subtest(void)
 {
-	int dir = igt_sysfs_open(drm_fd, NULL);
-	igt_require_f(dir != -1, "Can't open the sysfs directory\n");
-
-	disable_all_screens_and_wait(&ms_data);
+	char path[80];
 
-	read_files_from_dir(dir, 0);
-	close(dir);
+	igt_require_f(igt_sysfs_path(drm_fd, path, sizeof(path), NULL),
+		      "Can't find the sysfs directory\n");
+	walk_fs(path);
 }
 
 /* Make sure we don't suspend when we have the i915_forcewake_user file open. */