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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2019 Intel Corporation
*/
#include <linux/wait_bit.h>
#include "intel_runtime_pm.h"
#include "intel_wakeref.h"
#include "i915_drv.h"
int __intel_wakeref_get_first(struct intel_wakeref *wf)
{
intel_wakeref_t wakeref;
int ret = 0;
wakeref = intel_runtime_pm_get(&wf->i915->runtime_pm);
/*
* Treat get/put as different subclasses, as we may need to run
* the put callback from under the shrinker and do not want to
* cross-contanimate that callback with any extra work performed
* upon acquiring the wakeref.
*/
mutex_lock_nested(&wf->mutex, SINGLE_DEPTH_NESTING);
if (!atomic_read(&wf->count)) {
INTEL_WAKEREF_BUG_ON(wf->wakeref);
wf->wakeref = wakeref;
wakeref = 0;
ret = wf->ops->get(wf);
if (ret) {
wakeref = xchg(&wf->wakeref, 0);
wake_up_var(&wf->wakeref);
goto unlock;
}
smp_mb__before_atomic(); /* release wf->count */
}
atomic_inc(&wf->count);
INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
unlock:
mutex_unlock(&wf->mutex);
if (unlikely(wakeref))
intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref);
return ret;
}
static void ____intel_wakeref_put_last(struct intel_wakeref *wf)
{
intel_wakeref_t wakeref = 0;
INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
if (unlikely(!atomic_dec_and_test(&wf->count)))
goto unlock;
/* ops->put() must reschedule its own release on error/deferral */
if (likely(!wf->ops->put(wf))) {
INTEL_WAKEREF_BUG_ON(!wf->wakeref);
wakeref = xchg(&wf->wakeref, 0);
wake_up_var(&wf->wakeref);
}
unlock:
mutex_unlock(&wf->mutex);
if (wakeref)
intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref);
}
void __intel_wakeref_put_last(struct intel_wakeref *wf, unsigned long flags)
{
INTEL_WAKEREF_BUG_ON(delayed_work_pending(&wf->work));
/* Assume we are not in process context and so cannot sleep. */
if (flags & INTEL_WAKEREF_PUT_ASYNC || !mutex_trylock(&wf->mutex)) {
mod_delayed_work(wf->i915->unordered_wq, &wf->work,
FIELD_GET(INTEL_WAKEREF_PUT_DELAY, flags));
return;
}
____intel_wakeref_put_last(wf);
}
static void __intel_wakeref_put_work(struct work_struct *wrk)
{
struct intel_wakeref *wf = container_of(wrk, typeof(*wf), work.work);
if (atomic_add_unless(&wf->count, -1, 1))
return;
mutex_lock(&wf->mutex);
____intel_wakeref_put_last(wf);
}
void __intel_wakeref_init(struct intel_wakeref *wf,
struct drm_i915_private *i915,
const struct intel_wakeref_ops *ops,
struct intel_wakeref_lockclass *key,
const char *name)
{
wf->i915 = i915;
wf->ops = ops;
__mutex_init(&wf->mutex, "wakeref.mutex", &key->mutex);
atomic_set(&wf->count, 0);
wf->wakeref = 0;
INIT_DELAYED_WORK(&wf->work, __intel_wakeref_put_work);
lockdep_init_map(&wf->work.work.lockdep_map,
"wakeref.work", &key->work, 0);
#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_WAKEREF)
ref_tracker_dir_init(&wf->debug, INTEL_REFTRACK_DEAD_COUNT, name);
#endif
}
int intel_wakeref_wait_for_idle(struct intel_wakeref *wf)
{
int err;
might_sleep();
err = wait_var_event_killable(&wf->wakeref,
!intel_wakeref_is_active(wf));
if (err)
return err;
intel_wakeref_unlock_wait(wf);
return 0;
}
static void wakeref_auto_timeout(struct timer_list *t)
{
struct intel_wakeref_auto *wf = from_timer(wf, t, timer);
intel_wakeref_t wakeref;
unsigned long flags;
if (!refcount_dec_and_lock_irqsave(&wf->count, &wf->lock, &flags))
return;
wakeref = fetch_and_zero(&wf->wakeref);
spin_unlock_irqrestore(&wf->lock, flags);
intel_runtime_pm_put(&wf->i915->runtime_pm, wakeref);
}
void intel_wakeref_auto_init(struct intel_wakeref_auto *wf,
struct drm_i915_private *i915)
{
spin_lock_init(&wf->lock);
timer_setup(&wf->timer, wakeref_auto_timeout, 0);
refcount_set(&wf->count, 0);
wf->wakeref = 0;
wf->i915 = i915;
}
void intel_wakeref_auto(struct intel_wakeref_auto *wf, unsigned long timeout)
{
unsigned long flags;
if (!timeout) {
if (del_timer_sync(&wf->timer))
wakeref_auto_timeout(&wf->timer);
return;
}
/* Our mission is that we only extend an already active wakeref */
assert_rpm_wakelock_held(&wf->i915->runtime_pm);
if (!refcount_inc_not_zero(&wf->count)) {
spin_lock_irqsave(&wf->lock, flags);
if (!refcount_inc_not_zero(&wf->count)) {
INTEL_WAKEREF_BUG_ON(wf->wakeref);
wf->wakeref =
intel_runtime_pm_get_if_in_use(&wf->i915->runtime_pm);
refcount_set(&wf->count, 1);
}
spin_unlock_irqrestore(&wf->lock, flags);
}
/*
* If we extend a pending timer, we will only get a single timer
* callback and so need to cancel the local inc by running the
* elided callback to keep the wf->count balanced.
*/
if (mod_timer(&wf->timer, jiffies + timeout))
wakeref_auto_timeout(&wf->timer);
}
void intel_wakeref_auto_fini(struct intel_wakeref_auto *wf)
{
intel_wakeref_auto(wf, 0);
INTEL_WAKEREF_BUG_ON(wf->wakeref);
}
void intel_ref_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);
}
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