diff options
author | Ole Henrik Jahren <olehenja@alumni.ntnu.no> | 2011-03-06 20:42:39 +0100 |
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committer | Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> | 2011-04-13 15:46:52 +0200 |
commit | 6e2ad51190cdb11b364377882134513f60dec6b9 (patch) | |
tree | ea112778575ab257cb9d90638deec4bd676443a1 | |
parent | 51ef85d8f9ae24475a0cb1bd772258eafec91c69 (diff) | |
download | op-kernel-dev-6e2ad51190cdb11b364377882134513f60dec6b9.zip op-kernel-dev-6e2ad51190cdb11b364377882134513f60dec6b9.tar.gz |
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>
-rw-r--r-- | arch/avr32/mach-at32ap/clock.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/arch/avr32/mach-at32ap/clock.c b/arch/avr32/mach-at32ap/clock.c index 442f08c..86925fd 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); |