Message-Id: <20230224-track_gt-v4-9-464e8ab4c9ab@intel.com>
Date:   Mon, 06 Mar 2023 17:32:05 +0100
From:   Andrzej Hajda <andrzej.hajda@...el.com>
To:     Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>
Cc:     linux-kernel@...r.kernel.org, intel-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org,
        Chris Wilson <chris@...is-wilson.co.uk>,
        netdev@...r.kernel.org, Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Chris Wilson <chris.p.wilson@...el.com>
Subject: [PATCH v4 09/10] drm/i915: replace Intel internal tracker with kernel
 core ref_tracker

Beside reusing existing code, the main advantage of ref_tracker is
tracking per instance of wakeref. It allows also to catch double
put.
On the other side we lose information about the first acquire and
the last release, but the advantages outweigh it.

v2: Call ref_tracker_dir_exit() only at driver shutdown not during
    suspend so add intel_runtime_pm_driver_last_release (Nirmoy)

Signed-off-by: Andrzej Hajda <andrzej.hajda@...el.com>
---
 drivers/gpu/drm/i915/Kconfig.debug                 |  11 +-
 drivers/gpu/drm/i915/Makefile                      |   3 -
 drivers/gpu/drm/i915/display/intel_display_power.c |   2 +-
 drivers/gpu/drm/i915/gt/intel_engine_pm.c          |   2 +-
 drivers/gpu/drm/i915/gt/intel_gt_pm.c              |   2 +-
 drivers/gpu/drm/i915/i915_driver.c                 |   2 +-
 drivers/gpu/drm/i915/intel_runtime_pm.c            |  27 ++-
 drivers/gpu/drm/i915/intel_runtime_pm.h            |   3 +-
 drivers/gpu/drm/i915/intel_wakeref.c               |   5 +-
 drivers/gpu/drm/i915/intel_wakeref.h               |  72 ++++++-
 drivers/gpu/drm/i915/intel_wakeref_tracker.c       | 234 ---------------------
 drivers/gpu/drm/i915/intel_wakeref_tracker.h       |  76 -------
 12 files changed, 89 insertions(+), 350 deletions(-)

diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
index 63b77dc48d4394..d26fb4569873ea 100644
--- a/drivers/gpu/drm/i915/Kconfig.debug
+++ b/drivers/gpu/drm/i915/Kconfig.debug
@@ -24,6 +24,7 @@ config DRM_I915_DEBUG
 	select DEBUG_FS
 	select PREEMPT_COUNT
 	select I2C_CHARDEV
+	select REF_TRACKER
 	select STACKDEPOT
 	select STACKTRACE
 	select DRM_DP_AUX_CHARDEV
@@ -38,7 +39,6 @@ config DRM_I915_DEBUG
 	select DRM_I915_DEBUG_GEM
 	select DRM_I915_DEBUG_GEM_ONCE
 	select DRM_I915_DEBUG_MMIO
-	select DRM_I915_TRACK_WAKEREF
 	select DRM_I915_DEBUG_RUNTIME_PM
 	select DRM_I915_DEBUG_WAKEREF
 	select DRM_I915_SW_FENCE_DEBUG_OBJECTS
@@ -230,18 +230,13 @@ config DRM_I915_DEBUG_VBLANK_EVADE
 
 	  If in doubt, say "N".
 
-config DRM_I915_TRACK_WAKEREF
-	depends on STACKDEPOT
-	depends on STACKTRACE
-	bool
-
 config DRM_I915_DEBUG_RUNTIME_PM
 	bool "Enable extra state checking for runtime PM"
 	depends on DRM_I915
 	default n
+	select REF_TRACKER
 	select STACKDEPOT
 	select STACKTRACE
-	select DRM_I915_TRACK_WAKEREF
 	help
 	  Choose this option to turn on extra state checking for the
 	  runtime PM functionality. This may introduce overhead during
@@ -255,9 +250,9 @@ config DRM_I915_DEBUG_WAKEREF
 	bool "Enable extra tracking for wakerefs"
 	depends on DRM_I915
 	default n
+	select REF_TRACKER
 	select STACKDEPOT
 	select STACKTRACE
-	select DRM_I915_TRACK_WAKEREF
 	help
 	  Choose this option to turn on extra state checking and usage
 	  tracking for the wakerefPM functionality. This may introduce
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 42daff6d575a82..8d64846430f8aa 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -82,9 +82,6 @@ i915-$(CONFIG_DEBUG_FS) += \
 	display/intel_display_debugfs.o \
 	display/intel_pipe_crc.o
 
-i915-$(CONFIG_DRM_I915_TRACK_WAKEREF) += \
-	intel_wakeref_tracker.o
-
 i915-$(CONFIG_PERF_EVENTS) += i915_pmu.o
 
 # "Graphics Technology" (aka we talk to the gpu)
diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 743b919bb2cfd7..56c0a443f45c75 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -403,7 +403,7 @@ print_async_put_domains_state(struct i915_power_domains *power_domains)
 						     struct drm_i915_private,
 						     display.power.domains);
 
-	drm_dbg(&i915->drm, "async_put_wakeref %u\n",
+	drm_dbg(&i915->drm, "async_put_wakeref %lu\n",
 		power_domains->async_put_wakeref);
 
 	print_power_domains(power_domains, "async_put_domains[0]",
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pm.c b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
index 7db9229d28639c..7063dea2112943 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pm.c
@@ -289,7 +289,7 @@ void intel_engine_init__pm(struct intel_engine_cs *engine)
 {
 	struct intel_runtime_pm *rpm = engine->uncore->rpm;
 
-	intel_wakeref_init(&engine->wakeref, rpm, &wf_ops);
+	intel_wakeref_init(&engine->wakeref, rpm, &wf_ops, engine->name);
 	intel_engine_init_heartbeat(engine);
 
 	intel_gsc_idle_msg_enable(engine);
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index 302f908b37fb2e..7f92aa02b2a013 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -166,7 +166,7 @@ void intel_gt_pm_init_early(struct intel_gt *gt)
 	 * runtime_pm is per-device rather than per-tile, so this is still the
 	 * correct structure.
 	 */
-	intel_wakeref_init(&gt->wakeref, &gt->i915->runtime_pm, &wf_ops);
+	intel_wakeref_init(&gt->wakeref, &gt->i915->runtime_pm, &wf_ops, "GT");
 	seqcount_mutex_init(&gt->stats.lock, &gt->wakeref.mutex);
 }
 
diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
index e3244972521cb1..e971670f4a0e98 100644
--- a/drivers/gpu/drm/i915/i915_driver.c
+++ b/drivers/gpu/drm/i915/i915_driver.c
@@ -1017,7 +1017,7 @@ void i915_driver_shutdown(struct drm_i915_private *i915)
 	intel_power_domains_driver_remove(i915);
 	enable_rpm_wakeref_asserts(&i915->runtime_pm);
 
-	intel_runtime_pm_driver_release(&i915->runtime_pm);
+	intel_runtime_pm_driver_last_release(&i915->runtime_pm);
 }
 
 static bool suspend_to_idle(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
index 43149cf12dc864..7e05098e5d3276 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.c
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
@@ -54,7 +54,7 @@
 
 static void init_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
 {
-	intel_wakeref_tracker_init(&rpm->debug);
+	ref_tracker_dir_init(&rpm->debug, INTEL_REFTRACK_DEAD_COUNT, dev_name(rpm->kdev));
 }
 
 static intel_wakeref_t
@@ -63,26 +63,26 @@ track_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm)
 	if (!rpm->available || rpm->no_wakeref_tracking)
 		return -1;
 
-	return intel_wakeref_tracker_add(&rpm->debug);
+	return intel_ref_tracker_alloc(&rpm->debug);
 }
 
 static void untrack_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
 					     intel_wakeref_t wakeref)
 {
-	intel_wakeref_tracker_remove(&rpm->debug, wakeref);
+	if (!rpm->available || rpm->no_wakeref_tracking)
+		return;
+
+	intel_ref_tracker_free(&rpm->debug, wakeref);
 }
 
 static void untrack_all_intel_runtime_pm_wakerefs(struct intel_runtime_pm *rpm)
 {
-	struct drm_printer p = drm_debug_printer("i915");
-
-	intel_wakeref_tracker_reset(&rpm->debug, &p);
+	ref_tracker_dir_exit(&rpm->debug);
 }
 
 static noinline void
 __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
 {
-	struct intel_wakeref_tracker saved;
 	unsigned long flags;
 
 	if (!atomic_dec_and_lock_irqsave(&rpm->wakeref_count,
@@ -90,15 +90,8 @@ __intel_wakeref_dec_and_check_tracking(struct intel_runtime_pm *rpm)
 					 flags))
 		return;
 
-	saved = __intel_wakeref_tracker_reset(&rpm->debug);
+	__ref_tracker_dir_print(&rpm->debug, INTEL_REFTRACK_PRINT_LIMIT);
 	spin_unlock_irqrestore(&rpm->debug.lock, flags);
-
-	if (saved.count) {
-		struct drm_printer p = drm_debug_printer("i915");
-
-		__intel_wakeref_tracker_show(&saved, &p);
-		intel_wakeref_tracker_fini(&saved);
-	}
 }
 
 void print_intel_runtime_pm_wakeref(struct intel_runtime_pm *rpm,
@@ -455,7 +448,11 @@ void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm)
 		 "i915 raw-wakerefs=%d wakelocks=%d on cleanup\n",
 		 intel_rpm_raw_wakeref_count(count),
 		 intel_rpm_wakelock_count(count));
+}
 
+void intel_runtime_pm_driver_last_release(struct intel_runtime_pm *rpm)
+{
+	intel_runtime_pm_driver_release(rpm);
 	untrack_all_intel_runtime_pm_wakerefs(rpm);
 }
 
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.h b/drivers/gpu/drm/i915/intel_runtime_pm.h
index a8dc2baf79844f..2f81d685bdb4d1 100644
--- a/drivers/gpu/drm/i915/intel_runtime_pm.h
+++ b/drivers/gpu/drm/i915/intel_runtime_pm.h
@@ -83,7 +83,7 @@ struct intel_runtime_pm {
 	 * paired rpm_put) we can remove corresponding pairs of and keep
 	 * the array trimmed to active wakerefs.
 	 */
-	struct intel_wakeref_tracker debug;
+	struct ref_tracker_dir debug;
 #endif
 };
 
@@ -187,6 +187,7 @@ void intel_runtime_pm_init_early(struct intel_runtime_pm *rpm);
 void intel_runtime_pm_enable(struct intel_runtime_pm *rpm);
 void intel_runtime_pm_disable(struct intel_runtime_pm *rpm);
 void intel_runtime_pm_driver_release(struct intel_runtime_pm *rpm);
+void intel_runtime_pm_driver_last_release(struct intel_runtime_pm *rpm);
 
 intel_wakeref_t intel_runtime_pm_get(struct intel_runtime_pm *rpm);
 intel_wakeref_t intel_runtime_pm_get_if_in_use(struct intel_runtime_pm *rpm);
diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
index db4887e33ea607..61f974d97a3757 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.c
+++ b/drivers/gpu/drm/i915/intel_wakeref.c
@@ -96,7 +96,8 @@ static void __intel_wakeref_put_work(struct work_struct *wrk)
 void __intel_wakeref_init(struct intel_wakeref *wf,
 			  struct intel_runtime_pm *rpm,
 			  const struct intel_wakeref_ops *ops,
-			  struct intel_wakeref_lockclass *key)
+			  struct intel_wakeref_lockclass *key,
+			  const char *name)
 {
 	wf->rpm = rpm;
 	wf->ops = ops;
@@ -110,7 +111,7 @@ void __intel_wakeref_init(struct intel_wakeref *wf,
 			 "wakeref.work", &key->work, 0);
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
-	intel_wakeref_tracker_init(&wf->debug);
+	ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, name);
 #endif
 }
 
diff --git a/drivers/gpu/drm/i915/intel_wakeref.h b/drivers/gpu/drm/i915/intel_wakeref.h
index f2de4ccb7f5377..cf6828f13943d7 100644
--- a/drivers/gpu/drm/i915/intel_wakeref.h
+++ b/drivers/gpu/drm/i915/intel_wakeref.h
@@ -7,17 +7,24 @@
 #ifndef INTEL_WAKEREF_H
 #define INTEL_WAKEREF_H
 
+#include <drm/drm_print.h>
+
 #include <linux/atomic.h>
 #include <linux/bitfield.h>
 #include <linux/bits.h>
 #include <linux/lockdep.h>
 #include <linux/mutex.h>
 #include <linux/refcount.h>
+#include <linux/ref_tracker.h>
+#include <linux/slab.h>
 #include <linux/stackdepot.h>
 #include <linux/timer.h>
 #include <linux/workqueue.h>
 
-#include "intel_wakeref_tracker.h"
+typedef unsigned long intel_wakeref_t;
+
+#define INTEL_REFTRACK_DEAD_COUNT 16
+#define INTEL_REFTRACK_PRINT_LIMIT 16
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
 #define INTEL_WAKEREF_BUG_ON(expr) BUG_ON(expr)
@@ -45,7 +52,7 @@ struct intel_wakeref {
 	struct delayed_work work;
 
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
-	struct intel_wakeref_tracker debug;
+	struct ref_tracker_dir debug;
 #endif
 };
 
@@ -57,11 +64,12 @@ struct intel_wakeref_lockclass {
 void __intel_wakeref_init(struct intel_wakeref *wf,
 			  struct intel_runtime_pm *rpm,
 			  const struct intel_wakeref_ops *ops,
-			  struct intel_wakeref_lockclass *key);
-#define intel_wakeref_init(wf, rpm, ops) do {				\
+			  struct intel_wakeref_lockclass *key,
+			  const char *name);
+#define intel_wakeref_init(wf, rpm, ops, name) do {				\
 	static struct intel_wakeref_lockclass __key;			\
 									\
-	__intel_wakeref_init((wf), (rpm), (ops), &__key);		\
+	__intel_wakeref_init((wf), (rpm), (ops), &__key, name);		\
 } while (0)
 
 int __intel_wakeref_get_first(struct intel_wakeref *wf);
@@ -265,17 +273,67 @@ __intel_wakeref_defer_park(struct intel_wakeref *wf)
  */
 int intel_wakeref_wait_for_idle(struct intel_wakeref *wf);
 
+#define INTEL_WAKEREF_DEF ((intel_wakeref_t)(-1))
+
+static inline intel_wakeref_t intel_ref_tracker_alloc(struct ref_tracker_dir *dir)
+{
+	struct ref_tracker *user = NULL;
+
+	ref_tracker_alloc(dir, &user, GFP_NOWAIT);
+
+	return (intel_wakeref_t)user ?: INTEL_WAKEREF_DEF;
+}
+
+static inline void intel_ref_tracker_free(struct ref_tracker_dir *dir,
+					  intel_wakeref_t handle)
+{
+	struct ref_tracker *user;
+
+	user = (handle == INTEL_WAKEREF_DEF) ? NULL : (void *)handle;
+
+	ref_tracker_free(dir, &user);
+}
+
+static inline void
+intel_wakeref_tracker_show(struct ref_tracker_dir *dir,
+			   struct drm_printer *p)
+{
+	const size_t buf_size = PAGE_SIZE;
+	char *buf, *sb, *se;
+	size_t count;
+
+	buf = kmalloc(buf_size, GFP_NOWAIT);
+	if (!buf)
+		return;
+
+	count = ref_tracker_dir_snprint(dir, buf, buf_size);
+	if (!count)
+		goto free;
+	/* printk does not like big buffers, so we split it */
+	for (sb = buf; *sb; sb = se + 1) {
+		se = strchrnul(sb, '\n');
+		drm_printf(p, "%.*s", (int)(se - sb + 1), sb);
+		if (!*se)
+			break;
+	}
+	if (count >= buf_size)
+		drm_printf(p, "\n...dropped %zd extra bytes of leak report.\n",
+			   count + 1 - buf_size);
+free:
+	kfree(buf);
+}
+
 #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
 
 static inline intel_wakeref_t intel_wakeref_track(struct intel_wakeref *wf)
 {
-	return intel_wakeref_tracker_add(&wf->debug);
+	return intel_ref_tracker_alloc(&wf->debug);
 }
 
 static inline void intel_wakeref_untrack(struct intel_wakeref *wf,
 					 intel_wakeref_t handle)
 {
-	intel_wakeref_tracker_remove(&wf->debug, handle);
+	intel_ref_tracker_free(&wf->debug, handle);
 }
 
 static inline void intel_wakeref_show(struct intel_wakeref *wf,
diff --git a/drivers/gpu/drm/i915/intel_wakeref_tracker.c b/drivers/gpu/drm/i915/intel_wakeref_tracker.c
deleted file mode 100644
index c92035030a75cc..00000000000000
--- a/drivers/gpu/drm/i915/intel_wakeref_tracker.c
+++ /dev/null
@@ -1,234 +0,0 @@
-// SPDX-License-Identifier: MIT
-/*
- * Copyright © 2021 Intel Corporation
- */
-
-#include <linux/slab.h>
-#include <linux/stackdepot.h>
-#include <linux/stacktrace.h>
-#include <linux/sort.h>
-
-#include <drm/drm_print.h>
-
-#include "intel_wakeref_tracker.h"
-
-#define STACKDEPTH 8
-
-static noinline depot_stack_handle_t __save_depot_stack(void)
-{
-	unsigned long entries[STACKDEPTH];
-	unsigned int n;
-
-	n = stack_trace_save(entries, ARRAY_SIZE(entries), 1);
-	return stack_depot_save(entries, n, GFP_NOWAIT | __GFP_NOWARN);
-}
-
-static void __print_depot_stack(depot_stack_handle_t stack,
-				char *buf, int sz, int indent)
-{
-	unsigned long *entries;
-	unsigned int nr_entries;
-
-	nr_entries = stack_depot_fetch(stack, &entries);
-	stack_trace_snprint(buf, sz, entries, nr_entries, indent);
-}
-
-static int cmphandle(const void *_a, const void *_b)
-{
-	const depot_stack_handle_t * const a = _a, * const b = _b;
-
-	if (*a < *b)
-		return -1;
-	else if (*a > *b)
-		return 1;
-	else
-		return 0;
-}
-
-void
-__intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w,
-			     struct drm_printer *p)
-{
-	unsigned long i;
-	char *buf;
-
-	buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
-	if (!buf)
-		return;
-
-	if (w->last_acquire) {
-		__print_depot_stack(w->last_acquire, buf, PAGE_SIZE, 2);
-		drm_printf(p, "Wakeref last acquired:\n%s", buf);
-	}
-
-	if (w->last_release) {
-		__print_depot_stack(w->last_release, buf, PAGE_SIZE, 2);
-		drm_printf(p, "Wakeref last released:\n%s", buf);
-	}
-
-	drm_printf(p, "Wakeref count: %lu\n", w->count);
-
-	sort(w->owners, w->count, sizeof(*w->owners), cmphandle, NULL);
-
-	for (i = 0; i < w->count; i++) {
-		depot_stack_handle_t stack = w->owners[i];
-		unsigned long rep;
-
-		rep = 1;
-		while (i + 1 < w->count && w->owners[i + 1] == stack)
-			rep++, i++;
-		__print_depot_stack(stack, buf, PAGE_SIZE, 2);
-		drm_printf(p, "Wakeref x%lu taken at:\n%s", rep, buf);
-	}
-
-	kfree(buf);
-}
-
-void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w,
-				struct drm_printer *p)
-{
-	struct intel_wakeref_tracker tmp = {};
-
-	do {
-		unsigned long alloc = tmp.count;
-		depot_stack_handle_t *s;
-
-		spin_lock_irq(&w->lock);
-		tmp.count = w->count;
-		if (tmp.count <= alloc)
-			memcpy(tmp.owners, w->owners, tmp.count * sizeof(*s));
-		tmp.last_acquire = w->last_acquire;
-		tmp.last_release = w->last_release;
-		spin_unlock_irq(&w->lock);
-		if (tmp.count <= alloc)
-			break;
-
-		s = krealloc(tmp.owners,
-			     tmp.count * sizeof(*s),
-			     GFP_NOWAIT | __GFP_NOWARN);
-		if (!s)
-			goto out;
-
-		tmp.owners = s;
-	} while (1);
-
-	__intel_wakeref_tracker_show(&tmp, p);
-
-out:
-	intel_wakeref_tracker_fini(&tmp);
-}
-
-intel_wakeref_t intel_wakeref_tracker_add(struct intel_wakeref_tracker *w)
-{
-	depot_stack_handle_t stack, *stacks;
-	unsigned long flags;
-
-	stack = __save_depot_stack();
-	if (!stack)
-		return -1;
-
-	spin_lock_irqsave(&w->lock, flags);
-
-	if (!w->count)
-		w->last_acquire = stack;
-
-	stacks = krealloc(w->owners,
-			  (w->count + 1) * sizeof(*stacks),
-			  GFP_NOWAIT | __GFP_NOWARN);
-	if (stacks) {
-		stacks[w->count++] = stack;
-		w->owners = stacks;
-	} else {
-		stack = -1;
-	}
-
-	spin_unlock_irqrestore(&w->lock, flags);
-
-	return stack;
-}
-
-void intel_wakeref_tracker_remove(struct intel_wakeref_tracker *w,
-				  intel_wakeref_t stack)
-{
-	unsigned long flags, n;
-	bool found = false;
-
-	if (unlikely(stack == -1))
-		return;
-
-	spin_lock_irqsave(&w->lock, flags);
-	for (n = w->count; n--; ) {
-		if (w->owners[n] == stack) {
-			memmove(w->owners + n,
-				w->owners + n + 1,
-				(--w->count - n) * sizeof(stack));
-			found = true;
-			break;
-		}
-	}
-	spin_unlock_irqrestore(&w->lock, flags);
-
-	if (WARN(!found,
-		 "Unmatched wakeref %x, tracking %lu\n",
-		 stack, w->count)) {
-		char *buf;
-
-		buf = kmalloc(PAGE_SIZE, GFP_NOWAIT | __GFP_NOWARN);
-		if (!buf)
-			return;
-
-		__print_depot_stack(stack, buf, PAGE_SIZE, 2);
-		pr_err("wakeref %x from\n%s", stack, buf);
-
-		stack = READ_ONCE(w->last_release);
-		if (stack && !w->count) {
-			__print_depot_stack(stack, buf, PAGE_SIZE, 2);
-			pr_err("wakeref last released at\n%s", buf);
-		}
-
-		kfree(buf);
-	}
-}
-
-struct intel_wakeref_tracker
-__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w)
-{
-	struct intel_wakeref_tracker saved;
-
-	lockdep_assert_held(&w->lock);
-
-	saved = *w;
-
-	w->owners = NULL;
-	w->count = 0;
-	w->last_release = __save_depot_stack();
-
-	return saved;
-}
-
-void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w,
-				 struct drm_printer *p)
-{
-	struct intel_wakeref_tracker tmp;
-
-	spin_lock_irq(&w->lock);
-	tmp = __intel_wakeref_tracker_reset(w);
-	spin_unlock_irq(&w->lock);
-
-	if (tmp.count)
-		__intel_wakeref_tracker_show(&tmp, p);
-
-	intel_wakeref_tracker_fini(&tmp);
-}
-
-void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w)
-{
-	memset(w, 0, sizeof(*w));
-	spin_lock_init(&w->lock);
-	stack_depot_init();
-}
-
-void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w)
-{
-	kfree(w->owners);
-}
diff --git a/drivers/gpu/drm/i915/intel_wakeref_tracker.h b/drivers/gpu/drm/i915/intel_wakeref_tracker.h
deleted file mode 100644
index 61df68e28c0fbf..00000000000000
--- a/drivers/gpu/drm/i915/intel_wakeref_tracker.h
+++ /dev/null
@@ -1,76 +0,0 @@
-/* SPDX-License-Identifier: MIT */
-/*
- * Copyright © 2019 Intel Corporation
- */
-
-#ifndef INTEL_WAKEREF_TRACKER_H
-#define INTEL_WAKEREF_TRACKER_H
-
-#include <linux/kconfig.h>
-#include <linux/spinlock.h>
-#include <linux/stackdepot.h>
-
-typedef depot_stack_handle_t intel_wakeref_t;
-
-struct drm_printer;
-
-struct intel_wakeref_tracker {
-	spinlock_t lock;
-
-	depot_stack_handle_t last_acquire;
-	depot_stack_handle_t last_release;
-
-	depot_stack_handle_t *owners;
-	unsigned long count;
-};
-
-#if IS_ENABLED(CONFIG_DRM_I915_TRACK_WAKEREF)
-
-void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w);
-void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w);
-
-intel_wakeref_t intel_wakeref_tracker_add(struct intel_wakeref_tracker *w);
-void intel_wakeref_tracker_remove(struct intel_wakeref_tracker *w,
-			   intel_wakeref_t handle);
-
-struct intel_wakeref_tracker
-__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w);
-void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w,
-				 struct drm_printer *p);
-
-void __intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w,
-				  struct drm_printer *p);
-void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w,
-				struct drm_printer *p);
-
-#else
-
-static inline void intel_wakeref_tracker_init(struct intel_wakeref_tracker *w) {}
-static inline void intel_wakeref_tracker_fini(struct intel_wakeref_tracker *w) {}
-
-static inline intel_wakeref_t
-intel_wakeref_tracker_add(struct intel_wakeref_tracker *w)
-{
-	return -1;
-}
-
-static inline void
-intel_wakeref_untrack_remove(struct intel_wakeref_tracker *w, intel_wakeref_t handle) {}
-
-static inline struct intel_wakeref_tracker
-__intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w)
-{
-	return (struct intel_wakeref_tracker){};
-}
-
-static inline void intel_wakeref_tracker_reset(struct intel_wakeref_tracker *w,
-					       struct drm_printer *p)
-{
-}
-
-static inline void __intel_wakeref_tracker_show(const struct intel_wakeref_tracker *w, struct drm_printer *p) {}
-static inline void intel_wakeref_tracker_show(struct intel_wakeref_tracker *w, struct drm_printer *p) {}
-
-#endif
-
-#endif /* INTEL_WAKEREF_TRACKER_H */

-- 
2.34.1

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