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authorDoug Anderson <dianders@chromium.org>2015-05-01 09:01:27 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-05-17 09:51:33 -0700
commita854bc61460f987e5ed716897e8bbfa846b29ce0 (patch)
treebfa1ee5220ec599f95b6f2a00887cd67ef998880 /drivers
parent15e767666ce5a2e4e8ce31f8fe7e6576f392054e (diff)
downloadlinux-linaro-stable-a854bc61460f987e5ed716897e8bbfa846b29ce0.tar.gz
pinctrl: Don't just pretend to protect pinctrl_maps, do it for real
commit c5272a28566b00cce79127ad382406e0a8650690 upstream. Way back, when the world was a simpler place and there was no war, no evil, and no kernel bugs, there was just a single pinctrl lock. That was how the world was when (57291ce pinctrl: core device tree mapping table parsing support) was written. In that case, there were instances where the pinctrl mutex was already held when pinctrl_register_map() was called, hence a "locked" parameter was passed to the function to indicate that the mutex was already locked (so we shouldn't lock it again). A few years ago in (42fed7b pinctrl: move subsystem mutex to pinctrl_dev struct), we switched to a separate pinctrl_maps_mutex. ...but (oops) we forgot to re-think about the whole "locked" parameter for pinctrl_register_map(). Basically the "locked" parameter appears to still refer to whether the bigger pinctrl_dev mutex is locked, but we're using it to skip locks of our (now separate) pinctrl_maps_mutex. That's kind of a bad thing(TM). Probably nobody noticed because most of the calls to pinctrl_register_map happen at boot time and we've got synchronous device probing. ...and even cases where we're asynchronous don't end up actually hitting the race too often. ...but after banging my head against the wall for a bug that reproduced 1 out of 1000 reboots and lots of looking through kgdb, I finally noticed this. Anyway, we can now safely remove the "locked" parameter and go back to a war-free, evil-free, and kernel-bug-free world. Fixes: 42fed7ba44e4 ("pinctrl: move subsystem mutex to pinctrl_dev struct") Signed-off-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pinctrl/core.c10
-rw-r--r--drivers/pinctrl/core.h2
-rw-r--r--drivers/pinctrl/devicetree.c2
3 files changed, 6 insertions, 8 deletions
diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 9c9fc69a01b3..ea40c5139766 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -1077,7 +1077,7 @@ void devm_pinctrl_put(struct pinctrl *p)
EXPORT_SYMBOL_GPL(devm_pinctrl_put);
int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
- bool dup, bool locked)
+ bool dup)
{
int i, ret;
struct pinctrl_maps *maps_node;
@@ -1145,11 +1145,9 @@ int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
maps_node->maps = maps;
}
- if (!locked)
- mutex_lock(&pinctrl_maps_mutex);
+ mutex_lock(&pinctrl_maps_mutex);
list_add_tail(&maps_node->node, &pinctrl_maps);
- if (!locked)
- mutex_unlock(&pinctrl_maps_mutex);
+ mutex_unlock(&pinctrl_maps_mutex);
return 0;
}
@@ -1164,7 +1162,7 @@ int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
int pinctrl_register_mappings(struct pinctrl_map const *maps,
unsigned num_maps)
{
- return pinctrl_register_map(maps, num_maps, true, false);
+ return pinctrl_register_map(maps, num_maps, true);
}
void pinctrl_unregister_map(struct pinctrl_map const *map)
diff --git a/drivers/pinctrl/core.h b/drivers/pinctrl/core.h
index 75476b3d87da..b24ea846c867 100644
--- a/drivers/pinctrl/core.h
+++ b/drivers/pinctrl/core.h
@@ -183,7 +183,7 @@ static inline struct pin_desc *pin_desc_get(struct pinctrl_dev *pctldev,
}
int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
- bool dup, bool locked);
+ bool dup);
void pinctrl_unregister_map(struct pinctrl_map const *map);
extern int pinctrl_force_sleep(struct pinctrl_dev *pctldev);
diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c
index 340fb4e6c600..fd91c4c31f6b 100644
--- a/drivers/pinctrl/devicetree.c
+++ b/drivers/pinctrl/devicetree.c
@@ -92,7 +92,7 @@ static int dt_remember_or_free_map(struct pinctrl *p, const char *statename,
dt_map->num_maps = num_maps;
list_add_tail(&dt_map->node, &p->dt_maps);
- return pinctrl_register_map(map, num_maps, false, true);
+ return pinctrl_register_map(map, num_maps, false);
}
struct pinctrl_dev *of_pinctrl_get(struct device_node *np)