[PATCH 1/3] opp: Always add entries in dev_list with opp_table->lock held

From: Viresh Kumar
Date: Mon Nov 02 2020 - 00:21:49 EST


The readers of dev_list expect the updates to it to take place from
within the opp_table->lock and this is missing in the case where the
dev_list is updated for already managed OPPs.

Fix that by calling _add_opp_dev() from there and remove the now unused
_add_opp_dev_unlocked() callback. While at it, also reduce the length of
the critical section in _add_opp_dev().

Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
---
drivers/opp/core.c | 20 +++++---------------
1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 0e0a5269dc82..84035ab8bb31 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1036,8 +1036,8 @@ static void _remove_opp_dev(struct opp_device *opp_dev,
kfree(opp_dev);
}

-static struct opp_device *_add_opp_dev_unlocked(const struct device *dev,
- struct opp_table *opp_table)
+struct opp_device *_add_opp_dev(const struct device *dev,
+ struct opp_table *opp_table)
{
struct opp_device *opp_dev;

@@ -1048,7 +1048,9 @@ static struct opp_device *_add_opp_dev_unlocked(const struct device *dev,
/* Initialize opp-dev */
opp_dev->dev = dev;

+ mutex_lock(&opp_table->lock);
list_add(&opp_dev->node, &opp_table->dev_list);
+ mutex_unlock(&opp_table->lock);

/* Create debugfs entries for the opp_table */
opp_debug_register(opp_dev, opp_table);
@@ -1056,18 +1058,6 @@ static struct opp_device *_add_opp_dev_unlocked(const struct device *dev,
return opp_dev;
}

-struct opp_device *_add_opp_dev(const struct device *dev,
- struct opp_table *opp_table)
-{
- struct opp_device *opp_dev;
-
- mutex_lock(&opp_table->lock);
- opp_dev = _add_opp_dev_unlocked(dev, opp_table);
- mutex_unlock(&opp_table->lock);
-
- return opp_dev;
-}
-
static struct opp_table *_allocate_opp_table(struct device *dev, int index)
{
struct opp_table *opp_table;
@@ -1148,7 +1138,7 @@ static struct opp_table *_opp_get_opp_table(struct device *dev, int index)

opp_table = _managed_opp(dev, index);
if (opp_table) {
- if (!_add_opp_dev_unlocked(dev, opp_table)) {
+ if (!_add_opp_dev(dev, opp_table)) {
dev_pm_opp_put_opp_table(opp_table);
opp_table = ERR_PTR(-ENOMEM);
}
--
2.25.0.rc1.19.g042ed3e048af