DigiGoon/android_kernel_xiaomi_sm8350
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Revert "clk: Get runtime PM before walking tree during disable_unused"

Browse source 
This reverts commit 253ab38d1e which is
commit e581cf5d216289ef292d1a4036d53ce90e122469 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Ic3614277b0ce1e1eec3488d1f3db21cc538aa3d4
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman 2024-05-16 07:43:31 +00:00
parent 65d8957031
commit b9e6f92358
1 changed files with 12 additions and 105 deletions
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117
drivers/clk/clk.c
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@ -37,10 +37,6 @@ static HLIST_HEAD(clk_root_list);
static HLIST_HEAD(clk_orphan_list);
static LIST_HEAD(clk_notifier_list);
/* List of registered clks that use runtime PM */
static HLIST_HEAD(clk_rpm_list);
static DEFINE_MUTEX(clk_rpm_list_lock);
static const struct hlist_head *all_lists[] = {
&clk_root_list,
&clk_orphan_list,
@ -63,7 +59,6 @@ struct clk_core {
struct clk_hw *hw;
struct module *owner;
struct device *dev;
struct hlist_node rpm_node;
struct device_node *of_node;
struct clk_core *parent;
struct clk_parent_map *parents;
@ -136,89 +131,6 @@ static void clk_pm_runtime_put(struct clk_core *core)
pm_runtime_put_sync(core->dev);
}
/**
* clk_pm_runtime_get_all() - Runtime "get" all clk provider devices
*
* Call clk_pm_runtime_get() on all runtime PM enabled clks in the clk tree so
* that disabling unused clks avoids a deadlock where a device is runtime PM
* resuming/suspending and the runtime PM callback is trying to grab the
* prepare_lock for something like clk_prepare_enable() while
* clk_disable_unused_subtree() holds the prepare_lock and is trying to runtime
* PM resume/suspend the device as well.
*
* Context: Acquires the 'clk_rpm_list_lock' and returns with the lock held on
* success. Otherwise the lock is released on failure.
*
* Return: 0 on success, negative errno otherwise.
*/
static int clk_pm_runtime_get_all(void)
{
int ret;
struct clk_core *core, *failed;
/*
* Grab the list lock to prevent any new clks from being registered
* or unregistered until clk_pm_runtime_put_all().
*/
mutex_lock(&clk_rpm_list_lock);
/*
* Runtime PM "get" all the devices that are needed for the clks
* currently registered. Do this without holding the prepare_lock, to
* avoid the deadlock.
*/
hlist_for_each_entry(core, &clk_rpm_list, rpm_node) {
ret = clk_pm_runtime_get(core);
if (ret) {
failed = core;
pr_err("clk: Failed to runtime PM get '%s' for clk '%s'\n",
dev_name(failed->dev), failed->name);
goto err;
}
}
return 0;
err:
hlist_for_each_entry(core, &clk_rpm_list, rpm_node) {
if (core == failed)
break;
clk_pm_runtime_put(core);
}
mutex_unlock(&clk_rpm_list_lock);
return ret;
}
/**
* clk_pm_runtime_put_all() - Runtime "put" all clk provider devices
*
* Put the runtime PM references taken in clk_pm_runtime_get_all() and release
* the 'clk_rpm_list_lock'.
*/
static void clk_pm_runtime_put_all(void)
{
struct clk_core *core;
hlist_for_each_entry(core, &clk_rpm_list, rpm_node)
clk_pm_runtime_put(core);
mutex_unlock(&clk_rpm_list_lock);
}
static void clk_pm_runtime_init(struct clk_core *core)
{
struct device *dev = core->dev;
if (dev && pm_runtime_enabled(dev)) {
core->rpm_enabled = true;
mutex_lock(&clk_rpm_list_lock);
hlist_add_head(&core->rpm_node, &clk_rpm_list);
mutex_unlock(&clk_rpm_list_lock);
}
}
/*** locking ***/
static void clk_prepare_lock(void)
{
@ -1331,6 +1243,9 @@ static void clk_unprepare_unused_subtree(struct clk_core *core)
if (core->flags & CLK_IGNORE_UNUSED)
return;
if (clk_pm_runtime_get(core))
return;
if (clk_core_is_prepared(core)) {
trace_clk_unprepare(core);
if (core->ops->unprepare_unused)
@ -1339,6 +1254,8 @@ static void clk_unprepare_unused_subtree(struct clk_core *core)
core->ops->unprepare(core->hw);
trace_clk_unprepare_complete(core);
}
clk_pm_runtime_put(core);
}
static void clk_disable_unused_subtree(struct clk_core *core)
@ -1358,6 +1275,9 @@ static void clk_disable_unused_subtree(struct clk_core *core)
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_prepare_enable(core->parent);
if (clk_pm_runtime_get(core))
goto unprepare_out;
flags = clk_enable_lock();
if (core->enable_count)
@ -1382,6 +1302,8 @@ static void clk_disable_unused_subtree(struct clk_core *core)
unlock_out:
clk_enable_unlock(flags);
clk_pm_runtime_put(core);
unprepare_out:
if (core->flags & CLK_OPS_PARENT_ENABLE)
clk_core_disable_unprepare(core->parent);
}
@ -1397,7 +1319,6 @@ __setup("clk_ignore_unused", clk_ignore_unused_setup);
static int clk_disable_unused(void)
{
struct clk_core *core;
int ret;
if (clk_ignore_unused) {
pr_warn("clk: Not disabling unused clocks\n");
@ -1406,13 +1327,6 @@ static int clk_disable_unused(void)
pr_info("clk: Disabling unused clocks\n");
ret = clk_pm_runtime_get_all();
if (ret)
return ret;
/*
* Grab the prepare lock to keep the clk topology stable while iterating
* over clks.
*/
clk_prepare_lock();
hlist_for_each_entry(core, &clk_root_list, child_node)
@ -1429,8 +1343,6 @@ static int clk_disable_unused(void)
clk_prepare_unlock();
clk_pm_runtime_put_all();
return 0;
}
late_initcall_sync(clk_disable_unused);
@ -3894,12 +3806,6 @@ static void __clk_release(struct kref *ref)
{
struct clk_core *core = container_of(ref, struct clk_core, ref);
if (core->rpm_enabled) {
mutex_lock(&clk_rpm_list_lock);
hlist_del(&core->rpm_node);
mutex_unlock(&clk_rpm_list_lock);
}
clk_core_free_parent_map(core);
kfree_const(core->name);
kfree(core);
@ -3939,8 +3845,9 @@ __clk_register(struct device *dev, struct device_node *np, struct clk_hw *hw)
}
core->ops = init->ops;
if (dev && pm_runtime_enabled(dev))
core->rpm_enabled = true;
core->dev = dev;
clk_pm_runtime_init(core);
core->of_node = np;
if (dev && dev->driver)
core->owner = dev->driver->owner;