[CELL] spu_base: locking cleanup
Sort out the locking mess in spu_base and document the current rules.
As an added benefit spu_alloc* and spu_free don't block anymore.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
diff --git a/arch/powerpc/platforms/cell/spu_base.c b/arch/powerpc/platforms/cell/spu_base.c
index 03b4a8e..8617b50 100644
--- a/arch/powerpc/platforms/cell/spu_base.c
+++ b/arch/powerpc/platforms/cell/spu_base.c
@@ -42,13 +42,31 @@
EXPORT_SYMBOL_GPL(spu_management_ops);
const struct spu_priv1_ops *spu_priv1_ops;
-
-static LIST_HEAD(spu_full_list);
-static DEFINE_MUTEX(spu_mutex);
-static DEFINE_SPINLOCK(spu_list_lock);
-
EXPORT_SYMBOL_GPL(spu_priv1_ops);
+struct cbe_spu_info cbe_spu_info[MAX_NUMNODES];
+EXPORT_SYMBOL_GPL(cbe_spu_info);
+
+/*
+ * Protects cbe_spu_info and spu->number.
+ */
+static DEFINE_SPINLOCK(spu_lock);
+
+/*
+ * List of all spus in the system.
+ *
+ * This list is iterated by callers from irq context and callers that
+ * want to sleep. Thus modifications need to be done with both
+ * spu_full_list_lock and spu_full_list_mutex held, while iterating
+ * through it requires either of these locks.
+ *
+ * In addition spu_full_list_lock protects all assignmens to
+ * spu->mm.
+ */
+static LIST_HEAD(spu_full_list);
+static DEFINE_SPINLOCK(spu_full_list_lock);
+static DEFINE_MUTEX(spu_full_list_mutex);
+
void spu_invalidate_slbs(struct spu *spu)
{
struct spu_priv2 __iomem *priv2 = spu->priv2;
@@ -66,12 +84,12 @@
struct spu *spu;
unsigned long flags;
- spin_lock_irqsave(&spu_list_lock, flags);
+ spin_lock_irqsave(&spu_full_list_lock, flags);
list_for_each_entry(spu, &spu_full_list, full_list) {
if (spu->mm == mm)
spu_invalidate_slbs(spu);
}
- spin_unlock_irqrestore(&spu_list_lock, flags);
+ spin_unlock_irqrestore(&spu_full_list_lock, flags);
}
/* The hack below stinks... try to do something better one of
@@ -89,9 +107,9 @@
{
unsigned long flags;
- spin_lock_irqsave(&spu_list_lock, flags);
+ spin_lock_irqsave(&spu_full_list_lock, flags);
spu->mm = mm;
- spin_unlock_irqrestore(&spu_list_lock, flags);
+ spin_unlock_irqrestore(&spu_full_list_lock, flags);
if (mm)
mm_needs_global_tlbie(mm);
}
@@ -429,7 +447,7 @@
{
struct spu *spu, *ret = NULL;
- mutex_lock(&spu_mutex);
+ spin_lock(&spu_lock);
list_for_each_entry(spu, &cbe_spu_info[req_spu->node].free_spus, list) {
if (spu == req_spu) {
list_del_init(&spu->list);
@@ -439,7 +457,7 @@
break;
}
}
- mutex_unlock(&spu_mutex);
+ spin_unlock(&spu_lock);
return ret;
}
EXPORT_SYMBOL_GPL(spu_alloc_spu);
@@ -448,14 +466,14 @@
{
struct spu *spu = NULL;
- mutex_lock(&spu_mutex);
+ spin_lock(&spu_lock);
if (!list_empty(&cbe_spu_info[node].free_spus)) {
spu = list_entry(cbe_spu_info[node].free_spus.next, struct spu,
list);
list_del_init(&spu->list);
pr_debug("Got SPU %d %d\n", spu->number, spu->node);
}
- mutex_unlock(&spu_mutex);
+ spin_unlock(&spu_lock);
if (spu)
spu_init_channels(spu);
@@ -479,9 +497,9 @@
void spu_free(struct spu *spu)
{
- mutex_lock(&spu_mutex);
+ spin_lock(&spu_lock);
list_add_tail(&spu->list, &cbe_spu_info[spu->node].free_spus);
- mutex_unlock(&spu_mutex);
+ spin_unlock(&spu_lock);
}
EXPORT_SYMBOL_GPL(spu_free);
@@ -502,12 +520,12 @@
int spu_add_sysdev_attr(struct sysdev_attribute *attr)
{
struct spu *spu;
- mutex_lock(&spu_mutex);
+ mutex_lock(&spu_full_list_mutex);
list_for_each_entry(spu, &spu_full_list, full_list)
sysdev_create_file(&spu->sysdev, attr);
+ mutex_unlock(&spu_full_list_mutex);
- mutex_unlock(&spu_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(spu_add_sysdev_attr);
@@ -515,12 +533,12 @@
int spu_add_sysdev_attr_group(struct attribute_group *attrs)
{
struct spu *spu;
- mutex_lock(&spu_mutex);
+ mutex_lock(&spu_full_list_mutex);
list_for_each_entry(spu, &spu_full_list, full_list)
sysfs_create_group(&spu->sysdev.kobj, attrs);
+ mutex_unlock(&spu_full_list_mutex);
- mutex_unlock(&spu_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(spu_add_sysdev_attr_group);
@@ -529,24 +547,22 @@
void spu_remove_sysdev_attr(struct sysdev_attribute *attr)
{
struct spu *spu;
- mutex_lock(&spu_mutex);
+ mutex_lock(&spu_full_list_mutex);
list_for_each_entry(spu, &spu_full_list, full_list)
sysdev_remove_file(&spu->sysdev, attr);
-
- mutex_unlock(&spu_mutex);
+ mutex_unlock(&spu_full_list_mutex);
}
EXPORT_SYMBOL_GPL(spu_remove_sysdev_attr);
void spu_remove_sysdev_attr_group(struct attribute_group *attrs)
{
struct spu *spu;
- mutex_lock(&spu_mutex);
+ mutex_lock(&spu_full_list_mutex);
list_for_each_entry(spu, &spu_full_list, full_list)
sysfs_remove_group(&spu->sysdev.kobj, attrs);
-
- mutex_unlock(&spu_mutex);
+ mutex_unlock(&spu_full_list_mutex);
}
EXPORT_SYMBOL_GPL(spu_remove_sysdev_attr_group);
@@ -582,9 +598,9 @@
goto out;
spin_lock_init(&spu->register_lock);
- mutex_lock(&spu_mutex);
+ spin_lock(&spu_lock);
spu->number = number++;
- mutex_unlock(&spu_mutex);
+ spin_unlock(&spu_lock);
ret = spu_create_spu(spu, data);
@@ -601,14 +617,17 @@
if (ret)
goto out_free_irqs;
- mutex_lock(&spu_mutex);
- spin_lock_irqsave(&spu_list_lock, flags);
+ spin_lock(&spu_lock);
list_add(&spu->list, &cbe_spu_info[spu->node].free_spus);
list_add(&spu->cbe_list, &cbe_spu_info[spu->node].spus);
cbe_spu_info[spu->node].n_spus++;
+ spin_unlock(&spu_lock);
+
+ mutex_lock(&spu_full_list_mutex);
+ spin_lock_irqsave(&spu_full_list_lock, flags);
list_add(&spu->full_list, &spu_full_list);
- spin_unlock_irqrestore(&spu_list_lock, flags);
- mutex_unlock(&spu_mutex);
+ spin_unlock_irqrestore(&spu_full_list_lock, flags);
+ mutex_unlock(&spu_full_list_mutex);
spu->stats.util_state = SPU_UTIL_IDLE_LOADED;
ktime_get_ts(&ts);
@@ -675,9 +694,6 @@
static SYSDEV_ATTR(stat, 0644, spu_stat_show, NULL);
-struct cbe_spu_info cbe_spu_info[MAX_NUMNODES];
-EXPORT_SYMBOL_GPL(cbe_spu_info);
-
/* Hardcoded affinity idxs for QS20 */
#define SPES_PER_BE 8
static int QS20_reg_idxs[SPES_PER_BE] = { 0, 2, 4, 6, 7, 5, 3, 1 };
@@ -847,8 +863,10 @@
fb_append_extra_logo(&logo_spe_clut224, ret);
}
+ mutex_lock(&spu_full_list_mutex);
xmon_register_spus(&spu_full_list);
crash_register_spus(&spu_full_list);
+ mutex_unlock(&spu_full_list_mutex);
spu_add_sysdev_attr(&attr_stat);
if (of_has_vicinity()) {