diff options
| -rw-r--r-- | ipc/util.c | 103 |
1 files changed, 16 insertions, 87 deletions
@@ -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); } } |
