[PATCH] drm: make variable named "refcount" atomic, like most refcounts in the kernel.

Lionel Debroux
2014-04-26T16:06:15Z

Based on PaX.

---

From 7c712cadd97d43d03ff3d7ca04fd85bd8c6eb34a Mon Sep 17 00:00:00 2001
From: Lionel Debroux <lionel_debroux@yahoo.fr>
Date: Sat, 26 Apr 2014 15:53:55 +0200
Subject: drm: make variable named "refcount" atomic, like most refcounts in
the kernel.

Extracted from the PaX patch.

Signed-off-by: Lionel Debroux <lionel_debroux@yahoo.fr>
Cc: PaX Team <pageexec@freemail.hu>
---
drivers/gpu/drm/drm_global.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/drm_global.c b/drivers/gpu/drm/drm_global.c
index 3d2e91c..d31c4c9 100644
--- a/drivers/gpu/drm/drm_global.c
+++ b/drivers/gpu/drm/drm_global.c
@@ -36,7 +36,7 @@
struct drm_global_item {
struct mutex mutex;
void *object;
- int refcount;
+ atomic_t refcount;
};

static struct drm_global_item glob[DRM_GLOBAL_NUM];
@@ -49,7 +49,7 @@ void drm_global_init(void)
struct drm_global_item *item = &glob[i];
mutex_init(&item->mutex);
item->object = NULL;
- item->refcount = 0;
+ atomic_set(&item->refcount, 0);
}
}

@@ -59,7 +59,7 @@ void drm_global_release(void)
for (i = 0; i < DRM_GLOBAL_NUM; ++i) {
struct drm_global_item *item = &glob[i];
BUG_ON(item->object != NULL);
- BUG_ON(item->refcount != 0);
+ BUG_ON(atomic_read(&item->refcount) != 0);
}
}

@@ -69,7 +69,7 @@ int drm_global_item_ref(struct drm_global_reference *ref)
struct drm_global_item *item = &glob[ref->global_type];

mutex_lock(&item->mutex);
- if (item->refcount = 0) {
+ if (atomic_read(&item->refcount) = 0) {
item->object = kzalloc(ref->size, GFP_KERNEL);
if (unlikely(item->object = NULL)) {
ret = -ENOMEM;
@@ -82,7 +82,7 @@ int drm_global_item_ref(struct drm_global_reference *ref)
goto out_err;

}
- ++item->refcount;
+ atomic_inc(&item->refcount);
ref->object = item->object;
mutex_unlock(&item->mutex);
return 0;
@@ -98,9 +98,9 @@ void drm_global_item_unref(struct drm_global_reference *ref)
struct drm_global_item *item = &glob[ref->global_type];

mutex_lock(&item->mutex);
- BUG_ON(item->refcount = 0);
+ BUG_ON(atomic_read(&item->refcount) = 0);
BUG_ON(ref->object != item->object);
- if (--item->refcount = 0) {
+ if (atomic_dec_and_test(&item->refcount)) {
ref->release(ref);
item->object = NULL;
}
--
1.9.1.506.g7bf272c