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[CELL] spu_base: locking cleanup
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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>
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Christoph Hellwig authored and Arnd Bergmann committed Jul 20, 2007
1 parent 9e7cbcb commit 2414059
Showing 1 changed file with 51 additions and 33 deletions.
84 changes: 51 additions & 33 deletions arch/powerpc/platforms/cell/spu_base.c
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Original file line number Diff line number Diff line change
Expand Up @@ -42,12 +42,30 @@ const struct spu_management_ops *spu_management_ops;
EXPORT_SYMBOL_GPL(spu_management_ops);

const struct spu_priv1_ops *spu_priv1_ops;
EXPORT_SYMBOL_GPL(spu_priv1_ops);

static LIST_HEAD(spu_full_list);
static DEFINE_MUTEX(spu_mutex);
static DEFINE_SPINLOCK(spu_list_lock);
struct cbe_spu_info cbe_spu_info[MAX_NUMNODES];
EXPORT_SYMBOL_GPL(cbe_spu_info);

EXPORT_SYMBOL_GPL(spu_priv1_ops);
/*
* 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)
{
Expand All @@ -66,12 +84,12 @@ void spu_flush_all_slbs(struct mm_struct *mm)
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
Expand All @@ -89,9 +107,9 @@ void spu_associate_mm(struct spu *spu, struct mm_struct *mm)
{
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);
}
Expand Down Expand Up @@ -429,7 +447,7 @@ struct spu *spu_alloc_spu(struct spu *req_spu)
{
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);
Expand All @@ -439,7 +457,7 @@ struct spu *spu_alloc_spu(struct spu *req_spu)
break;
}
}
mutex_unlock(&spu_mutex);
spin_unlock(&spu_lock);
return ret;
}
EXPORT_SYMBOL_GPL(spu_alloc_spu);
Expand All @@ -448,14 +466,14 @@ struct spu *spu_alloc_node(int node)
{
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);
Expand All @@ -479,9 +497,9 @@ struct spu *spu_alloc(void)

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);

Expand All @@ -502,25 +520,25 @@ struct sysdev_class spu_sysdev_class = {
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);

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);
Expand All @@ -529,24 +547,22 @@ EXPORT_SYMBOL_GPL(spu_add_sysdev_attr_group);
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);

Expand Down Expand Up @@ -582,9 +598,9 @@ static int __init create_spu(void *data)
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);

Expand All @@ -601,14 +617,17 @@ static int __init create_spu(void *data)
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);
Expand Down Expand Up @@ -675,9 +694,6 @@ static ssize_t spu_stat_show(struct sys_device *sysdev, char *buf)

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 };
Expand Down Expand Up @@ -847,8 +863,10 @@ static int __init init_spu_base(void)
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()) {
Expand Down

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