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authorOle Henrik Jahren <olehenja@alumni.ntnu.no>2011-03-06 20:42:39 +0100
committerHans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>2011-04-13 15:46:52 +0200
commit6e2ad51190cdb11b364377882134513f60dec6b9 (patch)
treeea112778575ab257cb9d90638deec4bd676443a1 /arch/avr32
parent51ef85d8f9ae24475a0cb1bd772258eafec91c69 (diff)
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avr32: fix deadlock when reading clock list in debugfs
When writing out /sys/kernel/debug/at32ap_clk, clock list lock is being held while clk_get() is called. clk_get() attempts to take the same lock, which results in deadlock. Introduce and call lock free version, __clk_get(), instead. Signed-off-by: Ole Henrik Jahren <olehenja@alumni.ntnu.no> Cc: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>
Diffstat (limited to 'arch/avr32')
-rw-r--r--arch/avr32/mach-at32ap/clock.c24
1 files changed, 16 insertions, 8 deletions
diff --git a/arch/avr32/mach-at32ap/clock.c b/arch/avr32/mach-at32ap/clock.c
index 442f08c5e641..86925fd6ea5b 100644
--- a/arch/avr32/mach-at32ap/clock.c
+++ b/arch/avr32/mach-at32ap/clock.c
@@ -35,22 +35,30 @@ void at32_clk_register(struct clk *clk)
spin_unlock(&clk_list_lock);
}
-struct clk *clk_get(struct device *dev, const char *id)
+static struct clk *__clk_get(struct device *dev, const char *id)
{
struct clk *clk;
- spin_lock(&clk_list_lock);
-
list_for_each_entry(clk, &at32_clock_list, list) {
if (clk->dev == dev && strcmp(id, clk->name) == 0) {
- spin_unlock(&clk_list_lock);
return clk;
}
}
- spin_unlock(&clk_list_lock);
return ERR_PTR(-ENOENT);
}
+
+struct clk *clk_get(struct device *dev, const char *id)
+{
+ struct clk *clk;
+
+ spin_lock(&clk_list_lock);
+ clk = __clk_get(dev, id);
+ spin_unlock(&clk_list_lock);
+
+ return clk;
+}
+
EXPORT_SYMBOL(clk_get);
void clk_put(struct clk *clk)
@@ -257,15 +265,15 @@ static int clk_show(struct seq_file *s, void *unused)
spin_lock(&clk_list_lock);
/* show clock tree as derived from the three oscillators */
- clk = clk_get(NULL, "osc32k");
+ clk = __clk_get(NULL, "osc32k");
dump_clock(clk, &r);
clk_put(clk);
- clk = clk_get(NULL, "osc0");
+ clk = __clk_get(NULL, "osc0");
dump_clock(clk, &r);
clk_put(clk);
- clk = clk_get(NULL, "osc1");
+ clk = __clk_get(NULL, "osc1");
dump_clock(clk, &r);
clk_put(clk);