pmdomain: mtk-pm-domains: Fix spinlock recursion fix in probe

Remove scpsys_get_legacy_regmap(), replacing its usage with
of_find_node_with_property(). Explicitly call of_node_get(np) before each
of_find_node_with_property() to maintain correct node reference counting.

The of_find_node_with_property() function "consumes" its input by calling
of_node_put() internally, whether or not it finds a match.  Currently,
dev->of_node (np) is passed multiple times in sequence without incrementing
its reference count, causing it to be decremented multiple times and
risking early memory release.

Adding of_node_get(np) before each call balances the reference count,
preventing premature node release.

Fixes: c1bac49fe91f ("pmdomains: mtk-pm-domains: Fix spinlock recursion in probe")
Cc: stable@vger.kernel.org
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
Tested-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/pmdomain/mediatek/mtk-pm-domains.c b/drivers/pmdomain/mediatek/mtk-pm-domains.c
index 80561d27f2b2302941a5d00f23e585f449566d5d..f64f24d520ddd78a1e897444196db9cc531f7542 100644 (file)
--- a/drivers/pmdomain/mediatek/mtk-pm-domains.c
+++ b/drivers/pmdomain/mediatek/mtk-pm-domains.c
@@ -984,18 +984,6 @@ static void scpsys_domain_cleanup(struct scpsys *scpsys)
        }
 }
 
-static struct device_node *scpsys_get_legacy_regmap(struct device_node *np, const char *pn)
-{
-       struct device_node *local_node;
-
-       for_each_child_of_node(np, local_node) {
-               if (of_property_present(local_node, pn))
-                       return local_node;
-       }
-
-       return NULL;
-}
-
 static int scpsys_get_bus_protection_legacy(struct device *dev, struct scpsys *scpsys)
 {
        const u8 bp_blocks[3] = {
@@ -1017,7 +1005,8 @@ static int scpsys_get_bus_protection_legacy(struct device *dev, struct scpsys *s
         * this makes it then possible to allocate the array of bus_prot
         * regmaps and convert all to the new style handling.
         */
-       node = scpsys_get_legacy_regmap(np, "mediatek,infracfg");
+       of_node_get(np);
+       node = of_find_node_with_property(np, "mediatek,infracfg");
        if (node) {
                regmap[0] = syscon_regmap_lookup_by_phandle(node, "mediatek,infracfg");
                of_node_put(node);
@@ -1030,7 +1019,8 @@ static int scpsys_get_bus_protection_legacy(struct device *dev, struct scpsys *s
                regmap[0] = NULL;
        }
 
-       node = scpsys_get_legacy_regmap(np, "mediatek,smi");
+       of_node_get(np);
+       node = of_find_node_with_property(np, "mediatek,smi");
        if (node) {
                smi_np = of_parse_phandle(node, "mediatek,smi", 0);
                of_node_put(node);
@@ -1048,7 +1038,8 @@ static int scpsys_get_bus_protection_legacy(struct device *dev, struct scpsys *s
                regmap[1] = NULL;
        }
 
-       node = scpsys_get_legacy_regmap(np, "mediatek,infracfg-nao");
+       of_node_get(np);
+       node = of_find_node_with_property(np, "mediatek,infracfg-nao");
        if (node) {
                regmap[2] = syscon_regmap_lookup_by_phandle(node, "mediatek,infracfg-nao");
                num_regmaps++;