Improve utilisation of igt_debugfs_dir()

As we can export igt_debugfs_dir() to cache the path to our debugfs
directory, encourage a few more users to take advantage.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

5 files changed, 79 insertions, 126 deletions

diff --git a/lib/igt_debugfs.c b/lib/igt_debugfs.c
index 77769e0b..bd9ea3f0 100644
--- a/lib/igt_debugfs.c
+++ b/lib/igt_debugfs.c
@@ -131,7 +131,17 @@ const char *igt_debugfs_mount(void)
 	return "/sys/kernel/debug";
 }
 
-static int __igt_debugfs_dir(int device)
+/**
+ * igt_debugfs_dir:
+ * @device: fd of the device
+ *
+ * This opens the debugfs directory corresponding to device for use
+ * with igt_sysfs_get() and related functions.
+ *
+ * Returns:
+ * The directory fd, or -1 on failure.
+ */
+int igt_debugfs_dir(int device)
 {
 	struct stat st;
 	const char *debugfs_root;
@@ -204,7 +214,7 @@ int igt_debugfs_open(int device, const char *filename, int mode)
 {
 	int dir;
 
-	dir = __igt_debugfs_dir(device);
+	dir = igt_debugfs_dir(device);
 	if (dir < 0)
 		return dir;
 
@@ -226,13 +236,17 @@ FILE *igt_debugfs_fopen(int device,
 			const char *filename,
 			const char *mode)
 {
+	FILE *file;
 	int fd;
 
 	fd = igt_debugfs_open(device, filename, O_RDWR);
 	if (fd < 0)
 		return NULL;
 
-	return fdopen(fd, mode);
+	file = fdopen(fd, mode);
+	close(fd);
+
+	return file;
 }
 
 /**
@@ -250,7 +264,7 @@ void __igt_debugfs_read(int fd, const char *filename, char *buf, int buf_size)
 	int dir;
 	int len;
 
-	dir = __igt_debugfs_dir(fd);
+	dir = igt_debugfs_dir(fd);
 	len = igt_sysfs_read(dir, filename, buf, buf_size - 1);
 	if (len < 0)
 		len = 0;
@@ -278,7 +292,7 @@ bool igt_debugfs_search(int fd, const char *filename, const char *substring)
 	igt_assert(file);
 
 	while (getline(&line, &n, file) >= 0) {
-		matched = (strstr(line, substring) != NULL);
+		matched = strstr(line, substring) != NULL;
 		if (matched)
 			break;
 	}
@@ -419,7 +433,7 @@ static void igt_pipe_crc_reset(int drm_fd)
 	int fdir;
 	int fd;
 
-	fdir = __igt_debugfs_dir(drm_fd);
+	fdir = igt_debugfs_dir(drm_fd);
 	if (fdir < 0)
 		return;
 
@@ -949,7 +963,7 @@ bool igt_drop_caches_has(int drm_fd, uint64_t val)
 	int dir;
 
 	mask = 0;
-	dir = __igt_debugfs_dir(drm_fd);
+	dir = igt_debugfs_dir(drm_fd);
 	igt_sysfs_scanf(dir, "i915_gem_drop_caches", "0x%" PRIx64, &mask);
 	close(dir);
 
@@ -1043,7 +1057,7 @@ static int get_object_count(int fd)
 
 	igt_drop_caches_set(fd, DROP_RETIRE | DROP_ACTIVE | DROP_FREED);
 
-	dir = __igt_debugfs_dir(fd);
+	dir = igt_debugfs_dir(fd);
 	scanned = igt_sysfs_scanf(dir, "i915_gem_objects",
 				  "%i objects", &ret);
 	igt_assert_eq(scanned, 1);
@@ -1094,33 +1108,6 @@ int igt_get_stable_obj_count(int driver)
 	return obj_count;
 }
 
-
-/* Non-i915 specific debugfs API */
-
-/**
- * igt_debugfs_dir:
- * @device: fd of the device (or -1 to default to Intel)
- *
- * This opens the debugfs directory corresponding to device for use
- * with igt_sysfs_get() and related functions.
- *
- * Returns:
- * The directory fd, or -1 on failure.
- */
-int igt_debugfs_dir(int device)
-{
-	struct stat st;
-	char path[256];
-
-	if (fstat(device, &st) || !S_ISCHR(st.st_mode))
-		return -1;
-
-	sprintf(path, "%s/dri/%d",
-		igt_debugfs_mount(), (int)(st.st_rdev & 0xff));
-	igt_debug("Opening debugfs dir %s\n", path);
-	return open(path, O_RDONLY);
-}
-
 void igt_debugfs_dump(int device, const char *filename)
 {
 	char *contents;
diff --git a/lib/igt_debugfs.h b/lib/igt_debugfs.h
index ff396564..cdad562d 100644
--- a/lib/igt_debugfs.h
+++ b/lib/igt_debugfs.h
@@ -33,9 +33,10 @@ enum pipe;
 
 const char *igt_debugfs_mount(void);
 
+int igt_debugfs_dir(int device);
+
 int igt_debugfs_open(int fd, const char *filename, int mode);
-FILE *igt_debugfs_fopen(int fd, const char *filename,
-			const char *mode);
+FILE *igt_debugfs_fopen(int fd, const char *filename, const char *mode);
 void __igt_debugfs_read(int fd, const char *filename, char *buf, int buf_size);
 bool igt_debugfs_search(int fd, const char *filename, const char *substring);
 
@@ -203,8 +204,6 @@ void igt_enable_prefault(void);
  * gem buffer objects
  */
 int igt_get_stable_obj_count(int driver);
-
-int igt_debugfs_dir(int device);
 void igt_debugfs_dump(int device, const char *filename);
 
 #endif /* __IGT_DEBUGFS_H__ */
diff --git a/lib/igt_gt.c b/lib/igt_gt.c
index cc680862..976b0061 100644
--- a/lib/igt_gt.c
+++ b/lib/igt_gt.c
@@ -362,25 +362,16 @@ void igt_post_hang_ring(int fd, igt_hang_t arg)
  */
 void igt_force_gpu_reset(int drm_fd)
 {
-	FILE *file;
-	int fd, ret, wedged;
+	int dir, wedged;
 
 	igt_debug("Triggering GPU reset\n");
 
-	fd = igt_debugfs_open(drm_fd, "i915_wedged", O_RDWR);
-	igt_require(fd >= 0);
-
-	ret = write(fd, "-1\n", 3);
-	close(fd);
-
-	igt_assert_eq(ret, 3);
+	dir = igt_debugfs_dir(drm_fd);
 
-	file = igt_debugfs_fopen(drm_fd, "i915_wedged", "r");
-	igt_assert(file);
+	igt_sysfs_set(dir, "i915_wedged", "-1");
+	igt_sysfs_scanf(dir, "i915_wedged", "%d", &wedged);
 
-	wedged = 1;
-	igt_ignore_warn(fscanf(file, "%d", &wedged));
-	fclose(file);
+	close(dir);
 
 	igt_assert(!wedged);
 }
@@ -538,23 +529,19 @@ void igt_clflush_range(void *addr, int size)
  */
 unsigned intel_detect_and_clear_missed_interrupts(int fd)
 {
-	unsigned missed = 0;
-	FILE *file;
+	unsigned missed;
+	int dir;
 
 	gem_quiescent_gpu(fd);
 
-	file = igt_debugfs_fopen(fd, "i915_ring_missed_irq", "r");
-	if (file) {
-		igt_assert(fscanf(file, "%x", &missed) == 1);
-		fclose(file);
-	}
-	if (missed) {
-		file = igt_debugfs_fopen(fd, "i915_ring_missed_irq", "w");
-		if (file) {
-			fwrite("0\n", 1, 2, file);
-			fclose(file);
-		}
-	}
+	dir = igt_debugfs_dir(fd);
+
+	missed = 0;
+	igt_assert(igt_sysfs_scanf(dir, "i915_ring_missed_irq", "%x", &missed) == 1);
+	if (missed)
+		igt_sysfs_set(dir, "i915_ring_missed_irq", "0");
+
+	close(dir);
 
 	errno = 0;
 	return missed;
diff --git a/tests/drv_missed_irq.c b/tests/drv_missed_irq.c
index 652cbc20..fb81f277 100644
--- a/tests/drv_missed_irq.c
+++ b/tests/drv_missed_irq.c
@@ -26,11 +26,11 @@
 #include <sched.h>
 
 #include "igt.h"
+#include "igt_debugfs.h"
+#include "igt_sysfs.h"
 
 IGT_TEST_DESCRIPTION("Inject missed interrupts and make sure they are caught");
 
-static int drm_fd;
-
 static void trigger_missed_interrupt(int fd, unsigned ring)
 {
 	const int gen = intel_gen(intel_get_drm_devid(fd));
@@ -113,71 +113,49 @@ static void bind_to_cpu(int cpu)
 	igt_assert(sched_setscheduler(getpid(), SCHED_RR | SCHED_RESET_ON_FORK, &rt) == 0);
 }
 
-static uint32_t engine_mask(void)
+static void enable_missed_irq(int dir)
 {
-	uint32_t mask;
-	FILE *file;
-
-	file = igt_debugfs_fopen(drm_fd, "i915_ring_test_irq", "w");
-	fprintf(file, "0x%x", -1);
-	fclose(file);
-
-	mask = -1;
-	file = igt_debugfs_fopen(drm_fd, "i915_ring_test_irq", "r");
-	igt_ignore_warn(fscanf(file, "%x", &mask));
-	fclose(file);
-
-	file = igt_debugfs_fopen(drm_fd, "i915_ring_test_irq", "w");
-	fprintf(file, "0");
-	fclose(file);
-
-	return mask;
+	igt_sysfs_printf(dir, "i915_ring_test_irq", "0x%x", -1);
 }
 
-static void enable_missed_irq(void)
+static uint32_t disable_missed_irq(int dir)
 {
-	FILE *file;
-
-	file = igt_debugfs_fopen(drm_fd, "i915_ring_test_irq", "w");
-	fprintf(file, "0x%x", -1);
-	fclose(file);
-}
-
-static uint32_t disable_missed_irq(void)
-{
-	FILE *file;
 	uint32_t mask = 0;
 
-	file = igt_debugfs_fopen(drm_fd, "i915_ring_test_irq", "r");
-	igt_ignore_warn(fscanf(file, "%x", &mask));
-	fclose(file);
-
-	file = igt_debugfs_fopen(drm_fd, "i915_ring_test_irq", "w");
-	fprintf(file, "0");
-	fclose(file);
+	igt_sysfs_scanf(dir, "i915_ring_test_irq", "%x", &mask);
+	igt_sysfs_set(dir, "i915_ring_test_irq", "0");
 
 	return mask;
 }
 
+static uint32_t engine_mask(int dir)
+{
+	enable_missed_irq(dir);
+	return disable_missed_irq(dir);
+}
+
 igt_simple_main
 {
 	const struct intel_execution_engine *e;
 	unsigned expect_rings;
 	unsigned missed_rings;
 	unsigned check_rings;
+	int debugfs, device;
 
 	igt_skip_on_simulation();
 	bind_to_cpu(0);
 
-	drm_fd = drm_open_driver(DRIVER_INTEL);
-	igt_require_gem(drm_fd);
-	gem_require_mmap_wc(drm_fd);
-	igt_fork_hang_detector(drm_fd);
+	device = drm_open_driver(DRIVER_INTEL);
+	igt_require_gem(device);
+	gem_require_mmap_wc(device);
+	igt_fork_hang_detector(device);
+
+	debugfs = igt_debugfs_dir(device);
 
-	expect_rings = engine_mask();
+	expect_rings = engine_mask(debugfs);
 
 	igt_debug("Clearing rings %x\n", expect_rings);
-	intel_detect_and_clear_missed_interrupts(drm_fd);
+	intel_detect_and_clear_missed_interrupts(device);
 	for (e = intel_execution_engines; e->name; e++) {
 		if (expect_rings == -1 && e->exec_id)
 			continue;
@@ -187,12 +165,12 @@ igt_simple_main
 
 		igt_debug("Clearing ring %s [%x]\n",
 			  e->name, e->exec_id | e->flags);
-		trigger_missed_interrupt(drm_fd, e->exec_id | e->flags);
+		trigger_missed_interrupt(device, e->exec_id | e->flags);
 	}
-	igt_assert_eq(intel_detect_and_clear_missed_interrupts(drm_fd), 0);
+	igt_assert_eq(intel_detect_and_clear_missed_interrupts(device), 0);
 
 	igt_debug("Testing rings %x\n", expect_rings);
-	enable_missed_irq();
+	enable_missed_irq(debugfs);
 	for (e = intel_execution_engines; e->name; e++) {
 		if (expect_rings == -1 && e->exec_id)
 			continue;
@@ -202,11 +180,11 @@ igt_simple_main
 
 		igt_debug("Executing on ring %s [%x]\n",
 			  e->name, e->exec_id | e->flags);
-		trigger_missed_interrupt(drm_fd, e->exec_id | e->flags);
+		trigger_missed_interrupt(device, e->exec_id | e->flags);
 	}
-	missed_rings = intel_detect_and_clear_missed_interrupts(drm_fd);
+	missed_rings = intel_detect_and_clear_missed_interrupts(device);
 
-	check_rings = disable_missed_irq();
+	check_rings = disable_missed_irq(debugfs);
 	igt_assert_eq_u32(check_rings, expect_rings);
 
 	if (expect_rings == -1)
@@ -214,6 +192,7 @@ igt_simple_main
 	else
 		igt_assert_eq_u32(missed_rings, expect_rings);
 
+	close(debugfs);
 	igt_stop_hang_detector();
-	close(drm_fd);
+	close(device);
 }
diff --git a/tests/gem_exec_whisper.c b/tests/gem_exec_whisper.c
index 53988103..dab3a247 100644
--- a/tests/gem_exec_whisper.c
+++ b/tests/gem_exec_whisper.c
@@ -29,6 +29,7 @@
 
 #include "igt.h"
 #include "igt_gt.h"
+#include "igt_debugfs.h"
 #include "igt_sysfs.h"
 
 #define LOCAL_I915_EXEC_NO_RELOC (1<<11)
@@ -41,16 +42,11 @@
 
 #define VERIFY 0
 
-static void write_seqno(int fd, unsigned offset)
+static void write_seqno(int dir, unsigned offset)
 {
 	uint32_t seqno = UINT32_MAX - offset;
-	FILE *file;
 
-	file = igt_debugfs_fopen(fd, "i915_next_seqno", "w");
-	igt_assert(file);
-
-	igt_assert(fprintf(file, "0x%x", seqno) > 0);
-	fclose(file);
+	igt_sysfs_printf(dir, "i915_next_seqno", "0x%x", seqno);
 
 	igt_debug("next seqno set to: 0x%x\n", seqno);
 }
@@ -217,6 +213,9 @@ static void whisper(int fd, unsigned engine, unsigned flags)
 	unsigned int reloc_interruptions = 0;
 	unsigned int eb_migrations = 0;
 	uint64_t old_offset;
+	int debugfs;
+
+	debugfs = igt_debugfs_dir(fd);
 
 	nengine = 0;
 	if (engine == -1) {
@@ -341,7 +340,7 @@ static void whisper(int fd, unsigned engine, unsigned flags)
 				uint64_t offset;
 
 				if (!(flags & FORKED))
-					write_seqno(fd, pass);
+					write_seqno(debugfs, pass);
 
 				if (flags & HANG)
 					submit_hang(&hang, engines, nengine);
@@ -489,6 +488,8 @@ static void whisper(int fd, unsigned engine, unsigned flags)
 		fini_hang(&hang);
 	else
 		igt_assert_eq(intel_detect_and_clear_missed_interrupts(fd), 0);
+
+	close(debugfs);
 }
 
 static void print_welcome(int fd)