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-rw-r--r--ipc/util.c103
1 files changed, 16 insertions, 87 deletions
diff --git a/ipc/util.c b/ipc/util.c
index abfc13e8677f..809ec5ec8122 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -466,51 +466,13 @@ void ipc_free(void* ptr, int size)
kfree(ptr);
}
-/*
- * rcu allocations:
- * There are three headers that are prepended to the actual allocation:
- * - during use: ipc_rcu_hdr.
- * - during the rcu grace period: ipc_rcu_grace.
- * - [only if vmalloc]: ipc_rcu_sched.
- * Their lifetime doesn't overlap, thus the headers share the same memory.
- * Unlike a normal union, they are right-aligned, thus some container_of
- * forward/backward casting is necessary:
- */
-struct ipc_rcu_hdr
-{
- atomic_t refcount;
- int is_vmalloc;
- void *data[0];
-};
-
-
-struct ipc_rcu_grace
-{
+struct ipc_rcu {
struct rcu_head rcu;
+ atomic_t refcount;
/* "void *" makes sure alignment of following data is sane. */
void *data[0];
};
-struct ipc_rcu_sched
-{
- struct work_struct work;
- /* "void *" makes sure alignment of following data is sane. */
- void *data[0];
-};
-
-#define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \
- sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr))
-#define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \
- sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC)
-
-static inline int rcu_use_vmalloc(int size)
-{
- /* Too big for a single page? */
- if (HDRLEN_KMALLOC + size > PAGE_SIZE)
- return 1;
- return 0;
-}
-
/**
* ipc_rcu_alloc - allocate ipc and rcu space
* @size: size desired
@@ -520,74 +482,41 @@ static inline int rcu_use_vmalloc(int size)
*/
void *ipc_rcu_alloc(int size)
{
- void *out;
-
/*
- * We prepend the allocation with the rcu struct, and
- * workqueue if necessary (for vmalloc).
+ * We prepend the allocation with the rcu struct
*/
- if (rcu_use_vmalloc(size)) {
- out = vmalloc(HDRLEN_VMALLOC + size);
- 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)
- 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;
+ struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size);
+ if (unlikely(!out))
+ return NULL;
+ atomic_set(&out->refcount, 1);
+ return out->data;
}
int ipc_rcu_getref(void *ptr)
{
- return atomic_inc_not_zero(&container_of(ptr, struct ipc_rcu_hdr, data)->refcount);
-}
-
-static void ipc_do_vfree(struct work_struct *work)
-{
- vfree(container_of(work, struct ipc_rcu_sched, work));
+ return atomic_inc_not_zero(&container_of(ptr, struct ipc_rcu, data)->refcount);
}
/**
* ipc_schedule_free - free ipc + rcu space
* @head: RCU callback structure for queued work
- *
- * Since RCU callback function is called in bh,
- * we need to defer the vfree to schedule_work().
*/
static void ipc_schedule_free(struct rcu_head *head)
{
- struct ipc_rcu_grace *grace;
- struct ipc_rcu_sched *sched;
-
- grace = container_of(head, struct ipc_rcu_grace, rcu);
- sched = container_of(&(grace->data[0]), struct ipc_rcu_sched,
- data[0]);
-
- INIT_WORK(&sched->work, ipc_do_vfree);
- schedule_work(&sched->work);
+ vfree(container_of(head, struct ipc_rcu, rcu));
}
void ipc_rcu_putref(void *ptr)
{
- if (!atomic_dec_and_test(&container_of(ptr, struct ipc_rcu_hdr, data)->refcount))
+ struct ipc_rcu *p = container_of(ptr, struct ipc_rcu, data);
+
+ if (!atomic_dec_and_test(&p->refcount))
return;
- if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) {
- call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
- ipc_schedule_free);
+ if (is_vmalloc_addr(ptr)) {
+ call_rcu(&p->rcu, ipc_schedule_free);
} else {
- kfree_rcu(container_of(ptr, struct ipc_rcu_grace, data), rcu);
+ kfree_rcu(p, rcu);
}
}