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-rw-r--r--ipc/util.c48
1 files changed, 25 insertions, 23 deletions
diff --git a/ipc/util.c b/ipc/util.c
index 3df0af3158a5..579201e4bc01 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -439,9 +439,9 @@ void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
* NULL is returned if the allocation fails
*/
-void* ipc_alloc(int size)
+void *ipc_alloc(int size)
{
- void* out;
+ void *out;
if(size > PAGE_SIZE)
out = vmalloc(size);
else
@@ -478,7 +478,7 @@ void ipc_free(void* ptr, int size)
*/
struct ipc_rcu_hdr
{
- int refcount;
+ atomic_t refcount;
int is_vmalloc;
void *data[0];
};
@@ -516,39 +516,41 @@ static inline int rcu_use_vmalloc(int size)
* @size: size desired
*
* Allocate memory for the rcu header structure + the object.
- * Returns the pointer to the object.
- * NULL is returned if the allocation fails.
+ * Returns the pointer to the object or NULL upon failure.
*/
-
-void* ipc_rcu_alloc(int size)
+void *ipc_rcu_alloc(int size)
{
- void* out;
- /*
+ void *out;
+
+ /*
* We prepend the allocation with the rcu struct, and
- * workqueue if necessary (for vmalloc).
+ * workqueue if necessary (for vmalloc).
*/
if (rcu_use_vmalloc(size)) {
out = vmalloc(HDRLEN_VMALLOC + size);
- if (out) {
- out += HDRLEN_VMALLOC;
- container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1;
- container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
- }
+ if (!out)
+ goto done;
+
+ out += HDRLEN_VMALLOC;
+ container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1;
} else {
out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL);
- if (out) {
- out += HDRLEN_KMALLOC;
- container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0;
- container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
- }
+ if (!out)
+ goto done;
+
+ out += HDRLEN_KMALLOC;
+ container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0;
}
+ /* set reference counter no matter what kind of allocation was done */
+ atomic_set(&container_of(out, struct ipc_rcu_hdr, data)->refcount, 1);
+done:
return out;
}
-void ipc_rcu_getref(void *ptr)
+int ipc_rcu_getref(void *ptr)
{
- container_of(ptr, struct ipc_rcu_hdr, data)->refcount++;
+ return atomic_inc_not_zero(&container_of(ptr, struct ipc_rcu_hdr, data)->refcount);
}
static void ipc_do_vfree(struct work_struct *work)
@@ -578,7 +580,7 @@ static void ipc_schedule_free(struct rcu_head *head)
void ipc_rcu_putref(void *ptr)
{
- if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0)
+ if (!atomic_dec_and_test(&container_of(ptr, struct ipc_rcu_hdr, data)->refcount))
return;
if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) {