From: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>
The 'pwrdm_for_each()' function walks powerdomains with a spinlock
locked, so the the callbacks cannot do anything which may sleep.
This patch introduces a 'pwrdm_for_each_nolock()' helper which does
the same, but without the spinlock locked. This fixes the following
lockdep warning:
[ 0.000000] WARNING: at kernel/lockdep.c:2460 lockdep_trace_alloc+0xac/0xec()
[ 0.000000] Modules linked in:
(unwind_backtrace+0x0/0xdc) from [<c0045464>] (warn_slowpath_common+0x48/0x60)
(warn_slowpath_common+0x48/0x60) from [<c0067dd4>] (lockdep_trace_alloc+0xac/0xec)
(lockdep_trace_alloc+0xac/0xec) from [<c009da14>] (kmem_cache_alloc+0x1c/0xd0)
(kmem_cache_alloc+0x1c/0xd0) from [<c00b21d8>] (d_alloc+0x1c/0x1a4)
(d_alloc+0x1c/0x1a4) from [<c00a887c>] (__lookup_hash+0xd8/0x118)
(__lookup_hash+0xd8/0x118) from [<c00a9f20>] (lookup_one_len+0x84/0x94)
(lookup_one_len+0x84/0x94) from [<c010d12c>] (debugfs_create_file+0x8c/0x20c)
(debugfs_create_file+0x8c/0x20c) from [<c010d320>] (debugfs_create_dir+0x1c/0x20)
(debugfs_create_dir+0x1c/0x20) from [<c000e8cc>] (pwrdms_setup+0x60/0x90)
(pwrdms_setup+0x60/0x90) from [<c002e010>] (pwrdm_for_each+0x30/0x80)
(pwrdm_for_each+0x30/0x80) from [<c000e79c>] (pm_dbg_init+0x7c/0x14c)
(pm_dbg_init+0x7c/0x14c) from [<c00232b4>] (do_one_initcall+0x5c/0x1b8)
(do_one_initcall+0x5c/0x1b8) from [<c00083f8>] (kernel_init+0x90/0x10c)
(kernel_init+0x90/0x10c) from [<c00242c4>] (kernel_thread_exit+0x0/0x8)
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>
---
arch/arm/mach-omap2/pm-debug.c | 4 +-
arch/arm/mach-omap2/powerdomain.c | 39 +++++++++++++++++-------
arch/arm/plat-omap/include/mach/powerdomain.h | 2 +
3 files changed, 31 insertions(+), 14 deletions(-)
diff --git a/arch/arm/mach-omap2/pm-debug.c b/arch/arm/mach-omap2/pm-debug.c
index 1b4c160..2fc4d6a 100644
--- a/arch/arm/mach-omap2/pm-debug.c
+++ b/arch/arm/mach-omap2/pm-debug.c
@@ -541,7 +541,7 @@ static int __init pm_dbg_init(void)
printk(KERN_ERR "%s: only OMAP3 supported\n", __func__);
return -ENODEV;
}
-
+
d = debugfs_create_dir("pm_debug", NULL);
if (IS_ERR(d))
return PTR_ERR(d);
@@ -551,7 +551,7 @@ static int __init pm_dbg_init(void)
(void) debugfs_create_file("time", S_IRUGO,
d, (void *)DEBUG_FILE_TIMERS, &debug_fops);
- pwrdm_for_each(pwrdms_setup, (void *)d);
+ pwrdm_for_each_nolock(pwrdms_setup, (void *)d);
pm_dbg_dir = debugfs_create_dir("registers", d);
if (IS_ERR(pm_dbg_dir))
diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
index 2594cbf..f00289a 100644
--- a/arch/arm/mach-omap2/powerdomain.c
+++ b/arch/arm/mach-omap2/powerdomain.c
@@ -273,35 +273,50 @@ struct powerdomain *pwrdm_lookup(const char *name)
}
/**
- * pwrdm_for_each - call function on each registered clockdomain
+ * pwrdm_for_each_nolock - call function on each registered clockdomain
* @fn: callback function *
*
* Call the supplied function for each registered powerdomain. The
* callback function can return anything but 0 to bail out early from
- * the iterator. The callback function is called with the pwrdm_rwlock
- * held for reading, so no powerdomain structure manipulation
- * functions should be called from the callback, although hardware
- * powerdomain control functions are fine. Returns the last return
- * value of the callback function, which should be 0 for success or
- * anything else to indicate failure; or -EINVAL if the function
- * pointer is null.
+ * the iterator. Returns the last return value of the callback function, which
+ * should be 0 for success or anything else to indicate failure; or -EINVAL if
+ * the function pointer is null.
*/
-int pwrdm_for_each(int (*fn)(struct powerdomain *pwrdm, void *user),
- void *user)
+int pwrdm_for_each_nolock(int (*fn)(struct powerdomain *pwrdm, void *user),
+ void *user)
{
struct powerdomain *temp_pwrdm;
- unsigned long flags;
int ret = 0;
if (!fn)
return -EINVAL;
- read_lock_irqsave(&pwrdm_rwlock, flags);
list_for_each_entry(temp_pwrdm, &pwrdm_list, node) {
ret = (*fn)(temp_pwrdm, user);
if (ret)
break;
}
+
+ return ret;
+}
+
+/**
+ * pwrdm_for_each - call function on each registered clockdomain
+ * @fn: callback function *
+ *
+ * This function is the same as 'pwrdm_for_each_nolock()', but keeps the
+ * &pwrdm_rwlock locked for reading, so no powerdomain structure manipulation
+ * functions should be called from the callback, although hardware powerdomain
+ * control functions are fine.
+ */
+int pwrdm_for_each(int (*fn)(struct powerdomain *pwrdm, void *user),
+ void *user)
+{
+ unsigned long flags;
+ int ret;
+
+ read_lock_irqsave(&pwrdm_rwlock, flags);
+ ret = pwrdm_for_each_nolock(fn, user);
read_unlock_irqrestore(&pwrdm_rwlock, flags);
return ret;
diff --git a/arch/arm/plat-omap/include/mach/powerdomain.h b/arch/arm/plat-omap/include/mach/powerdomain.h
index 6271d85..fa64614 100644
--- a/arch/arm/plat-omap/include/mach/powerdomain.h
+++ b/arch/arm/plat-omap/include/mach/powerdomain.h
@@ -135,6 +135,8 @@ struct powerdomain *pwrdm_lookup(const char *name);
int pwrdm_for_each(int (*fn)(struct powerdomain *pwrdm, void *user),
void *user);
+int pwrdm_for_each_nolock(int (*fn)(struct powerdomain *pwrdm, void *user),
+ void *user);
int pwrdm_add_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm);
int pwrdm_del_clkdm(struct powerdomain *pwrdm, struct clockdomain *clkdm);
--
1.6.2.5
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