rcu: Convert trivial uses of call_rcu() to kfree_rcu()

From: Paul E. McKenney
Date: Mon Jul 11 2011 - 11:00:03 EST

Hello, Jiri!

Does the patch below qualify as trivial? If so, please feel free to
take it off my hands. ;-)

Thanx, Paul

------------------------------------------------------------------------

rcu: Convert trivial uses of call_rcu() to kfree_rcu()

A number of RCU callbacks just directly call kfree(), so these can use
the new kfree_rcu() interface, thus allowing these trivial RCU callback
functions to be removed.

Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>

arch/ia64/sn/kernel/irq.c | 14 ++------------
block/genhd.c | 10 +---------
drivers/scsi/libfc/fc_rport.c | 14 +-------------
ipc/sem.c | 10 ++--------
ipc/util.c | 16 +---------------
kernel/audit_tree.c | 8 +-------
kernel/sysctl.c | 11 +++--------
mm/vmalloc.c | 18 ++----------------
net/netfilter/xt_RATEEST.c | 8 +-------
security/selinux/netnode.c | 20 ++------------------
security/selinux/netport.c | 20 ++------------------
11 files changed, 18 insertions(+), 131 deletions(-)

diff --git a/arch/ia64/sn/kernel/irq.c b/arch/ia64/sn/kernel/irq.c
index 81a1f4e..485c42d 100644
--- a/arch/ia64/sn/kernel/irq.c
+++ b/arch/ia64/sn/kernel/irq.c
@@ -112,8 +112,6 @@ static void sn_ack_irq(struct irq_data *data)
irq_move_irq(data);
}

-static void sn_irq_info_free(struct rcu_head *head);
-
struct sn_irq_info *sn_retarget_vector(struct sn_irq_info *sn_irq_info,
nasid_t nasid, int slice)
{
@@ -177,7 +175,7 @@ struct sn_irq_info *sn_retarget_vector(struct sn_irq_info *sn_irq_info,
spin_lock(&sn_irq_info_lock);
list_replace_rcu(&sn_irq_info->list, &new_irq_info->list);
spin_unlock(&sn_irq_info_lock);
- call_rcu(&sn_irq_info->rcu, sn_irq_info_free);
+ kfree_rcu(sn_irq_info, rcu);


finish_up:
@@ -338,14 +336,6 @@ static void unregister_intr_pda(struct sn_irq_info *sn_irq_info)
rcu_read_unlock();
}

-static void sn_irq_info_free(struct rcu_head *head)
-{
- struct sn_irq_info *sn_irq_info;
-
- sn_irq_info = container_of(head, struct sn_irq_info, rcu);
- kfree(sn_irq_info);
-}
-
void sn_irq_fixup(struct pci_dev *pci_dev, struct sn_irq_info *sn_irq_info)
{
nasid_t nasid = sn_irq_info->irq_nasid;
@@ -399,7 +389,7 @@ void sn_irq_unfixup(struct pci_dev *pci_dev)
spin_unlock(&sn_irq_info_lock);
if (list_empty(sn_irq_lh[sn_irq_info->irq_irq]))
free_irq_vector(sn_irq_info->irq_irq);
- call_rcu(&sn_irq_info->rcu, sn_irq_info_free);
+ kfree_rcu(sn_irq_info, rcu);
pci_dev_put(pci_dev);

}
diff --git a/block/genhd.c b/block/genhd.c
index 3608289..6024b82 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1018,14 +1018,6 @@ static const struct attribute_group *disk_attr_groups[] = {
NULL
};

-static void disk_free_ptbl_rcu_cb(struct rcu_head *head)
-{
- struct disk_part_tbl *ptbl =
- container_of(head, struct disk_part_tbl, rcu_head);
-
- kfree(ptbl);
-}
-
/**
* disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
* @disk: disk to replace part_tbl for
@@ -1046,7 +1038,7 @@ static void disk_replace_part_tbl(struct gendisk *disk,

if (old_ptbl) {
rcu_assign_pointer(old_ptbl->last_lookup, NULL);
- call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb);
+ kfree_rcu(old_ptbl, rcu_head);
}
}

diff --git a/drivers/scsi/libfc/fc_rport.c b/drivers/scsi/libfc/fc_rport.c
index 49e1ccc..01e13a2 100644
--- a/drivers/scsi/libfc/fc_rport.c
+++ b/drivers/scsi/libfc/fc_rport.c
@@ -153,18 +153,6 @@ static struct fc_rport_priv *fc_rport_create(struct fc_lport *lport,
}

/**
- * fc_rport_free_rcu() - Free a remote port
- * @rcu: The rcu_head structure inside the remote port
- */
-static void fc_rport_free_rcu(struct rcu_head *rcu)
-{
- struct fc_rport_priv *rdata;
-
- rdata = container_of(rcu, struct fc_rport_priv, rcu);
- kfree(rdata);
-}
-
-/**
* fc_rport_destroy() - Free a remote port after last reference is released
* @kref: The remote port's kref
*/
@@ -173,7 +161,7 @@ static void fc_rport_destroy(struct kref *kref)
struct fc_rport_priv *rdata;

rdata = container_of(kref, struct fc_rport_priv, kref);
- call_rcu(&rdata->rcu, fc_rport_free_rcu);
+ kfree_rcu(rdata, rcu);
}

/**
diff --git a/ipc/sem.c b/ipc/sem.c
index 34193ed..8b929e6 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -689,12 +689,6 @@ static int count_semzcnt (struct sem_array * sma, ushort semnum)
return semzcnt;
}

-static void free_un(struct rcu_head *head)
-{
- struct sem_undo *un = container_of(head, struct sem_undo, rcu);
- kfree(un);
-}
-
/* Free a semaphore set. freeary() is called with sem_ids.rw_mutex locked
* as a writer and the spinlock for this semaphore set hold. sem_ids.rw_mutex
* remains locked on exit.
@@ -714,7 +708,7 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
un->semid = -1;
list_del_rcu(&un->list_proc);
spin_unlock(&un->ulp->lock);
- call_rcu(&un->rcu, free_un);
+ kfree_rcu(un, rcu);
}

/* Wake up all pending processes and let them fail with EIDRM. */
@@ -1612,7 +1606,7 @@ void exit_sem(struct task_struct *tsk)
sem_unlock(sma);
wake_up_sem_queue_do(&tasks);

- call_rcu(&un->rcu, free_un);
+ kfree_rcu(un, rcu);
}
kfree(ulp);
}
diff --git a/ipc/util.c b/ipc/util.c
index 5c0d289..75261a3 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -579,19 +579,6 @@ static void ipc_schedule_free(struct rcu_head *head)
schedule_work(&sched->work);
}

-/**
- * ipc_immediate_free - free ipc + rcu space
- * @head: RCU callback structure that contains pointer to be freed
- *
- * Free from the RCU callback context.
- */
-static void ipc_immediate_free(struct rcu_head *head)
-{
- struct ipc_rcu_grace *free =
- container_of(head, struct ipc_rcu_grace, rcu);
- kfree(free);
-}
-
void ipc_rcu_putref(void *ptr)
{
if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0)
@@ -601,8 +588,7 @@ void ipc_rcu_putref(void *ptr)
call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
ipc_schedule_free);
} else {
- call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
- ipc_immediate_free);
+ kfree_rcu(container_of(ptr, struct ipc_rcu_grace, data), rcu);
}
}

diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c
index e99dda0..5bf0790 100644
--- a/kernel/audit_tree.c
+++ b/kernel/audit_tree.c
@@ -93,16 +93,10 @@ static inline void get_tree(struct audit_tree *tree)
atomic_inc(&tree->count);
}

-static void __put_tree(struct rcu_head *rcu)
-{
- struct audit_tree *tree = container_of(rcu, struct audit_tree, head);
- kfree(tree);
-}
-
static inline void put_tree(struct audit_tree *tree)
{
if (atomic_dec_and_test(&tree->count))
- call_rcu(&tree->head, __put_tree);
+ kfree_rcu(tree, head);
}

/* to avoid bringing the entire thing in audit.h */
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index f175d98..11d65b5 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1590,16 +1590,11 @@ void sysctl_head_get(struct ctl_table_header *head)
spin_unlock(&sysctl_lock);
}

-static void free_head(struct rcu_head *rcu)
-{
- kfree(container_of(rcu, struct ctl_table_header, rcu));
-}
-
void sysctl_head_put(struct ctl_table_header *head)
{
spin_lock(&sysctl_lock);
if (!--head->count)
- call_rcu(&head->rcu, free_head);
+ kfree_rcu(head, rcu);
spin_unlock(&sysctl_lock);
}

@@ -1971,10 +1966,10 @@ void unregister_sysctl_table(struct ctl_table_header * header)
start_unregistering(header);
if (!--header->parent->count) {
WARN_ON(1);
- call_rcu(&header->parent->rcu, free_head);
+ kfree_rcu(header->parent, rcu);
}
if (!--header->count)
- call_rcu(&header->rcu, free_head);
+ kfree_rcu(header, rcu);
spin_unlock(&sysctl_lock);
}

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 1d34d75..ab8494c 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -452,13 +452,6 @@ overflow:
return ERR_PTR(-EBUSY);
}

-static void rcu_free_va(struct rcu_head *head)
-{
- struct vmap_area *va = container_of(head, struct vmap_area, rcu_head);
-
- kfree(va);
-}
-
static void __free_vmap_area(struct vmap_area *va)
{
BUG_ON(RB_EMPTY_NODE(&va->rb_node));
@@ -491,7 +484,7 @@ static void __free_vmap_area(struct vmap_area *va)
if (va->va_end > VMALLOC_START && va->va_end <= VMALLOC_END)
vmap_area_pcpu_hole = max(vmap_area_pcpu_hole, va->va_end);

- call_rcu(&va->rcu_head, rcu_free_va);
+ kfree_rcu(va, rcu_head);
}

/*
@@ -837,13 +830,6 @@ static struct vmap_block *new_vmap_block(gfp_t gfp_mask)
return vb;
}

-static void rcu_free_vb(struct rcu_head *head)
-{
- struct vmap_block *vb = container_of(head, struct vmap_block, rcu_head);
-
- kfree(vb);
-}
-
static void free_vmap_block(struct vmap_block *vb)
{
struct vmap_block *tmp;
@@ -856,7 +842,7 @@ static void free_vmap_block(struct vmap_block *vb)
BUG_ON(tmp != vb);

free_vmap_area_noflush(vb->va);
- call_rcu(&vb->rcu_head, rcu_free_vb);
+ kfree_rcu(vb, rcu_head);
}

static void purge_fragmented_blocks(int cpu)
diff --git a/net/netfilter/xt_RATEEST.c b/net/netfilter/xt_RATEEST.c
index de079abd..f264032 100644
--- a/net/netfilter/xt_RATEEST.c
+++ b/net/netfilter/xt_RATEEST.c
@@ -60,11 +60,6 @@ struct xt_rateest *xt_rateest_lookup(const char *name)
}
EXPORT_SYMBOL_GPL(xt_rateest_lookup);

-static void xt_rateest_free_rcu(struct rcu_head *head)
-{
- kfree(container_of(head, struct xt_rateest, rcu));
-}
-
void xt_rateest_put(struct xt_rateest *est)
{
mutex_lock(&xt_rateest_mutex);
@@ -75,7 +70,7 @@ void xt_rateest_put(struct xt_rateest *est)
* gen_estimator est_timer() might access est->lock or bstats,
* wait a RCU grace period before freeing 'est'
*/
- call_rcu(&est->rcu, xt_rateest_free_rcu);
+ kfree_rcu(est, rcu);
}
mutex_unlock(&xt_rateest_mutex);
}
@@ -188,7 +183,6 @@ static int __init xt_rateest_tg_init(void)
static void __exit xt_rateest_tg_fini(void)
{
xt_unregister_target(&xt_rateest_tg_reg);
- rcu_barrier(); /* Wait for completion of call_rcu()'s (xt_rateest_free_rcu) */
}


diff --git a/security/selinux/netnode.c b/security/selinux/netnode.c
index 3618251..8b691a8 100644
--- a/security/selinux/netnode.c
+++ b/security/selinux/netnode.c
@@ -69,22 +69,6 @@ static DEFINE_SPINLOCK(sel_netnode_lock);
static struct sel_netnode_bkt sel_netnode_hash[SEL_NETNODE_HASH_SIZE];

/**
- * sel_netnode_free - Frees a node entry
- * @p: the entry's RCU field
- *
- * Description:
- * This function is designed to be used as a callback to the call_rcu()
- * function so that memory allocated to a hash table node entry can be
- * released safely.
- *
- */
-static void sel_netnode_free(struct rcu_head *p)
-{
- struct sel_netnode *node = container_of(p, struct sel_netnode, rcu);
- kfree(node);
-}
-
-/**
* sel_netnode_hashfn_ipv4 - IPv4 hashing function for the node table
* @addr: IPv4 address
*
@@ -193,7 +177,7 @@ static void sel_netnode_insert(struct sel_netnode *node)
rcu_dereference(sel_netnode_hash[idx].list.prev),
struct sel_netnode, list);
list_del_rcu(&tail->list);
- call_rcu(&tail->rcu, sel_netnode_free);
+ kfree_rcu(tail, rcu);
} else
sel_netnode_hash[idx].size++;
}
@@ -306,7 +290,7 @@ static void sel_netnode_flush(void)
list_for_each_entry_safe(node, node_tmp,
&sel_netnode_hash[idx].list, list) {
list_del_rcu(&node->list);
- call_rcu(&node->rcu, sel_netnode_free);
+ kfree_rcu(node, rcu);
}
sel_netnode_hash[idx].size = 0;
}
diff --git a/security/selinux/netport.c b/security/selinux/netport.c
index cfe2d72..ae76e29 100644
--- a/security/selinux/netport.c
+++ b/security/selinux/netport.c
@@ -68,22 +68,6 @@ static DEFINE_SPINLOCK(sel_netport_lock);
static struct sel_netport_bkt sel_netport_hash[SEL_NETPORT_HASH_SIZE];

/**
- * sel_netport_free - Frees a port entry
- * @p: the entry's RCU field
- *
- * Description:
- * This function is designed to be used as a callback to the call_rcu()
- * function so that memory allocated to a hash table port entry can be
- * released safely.
- *
- */
-static void sel_netport_free(struct rcu_head *p)
-{
- struct sel_netport *port = container_of(p, struct sel_netport, rcu);
- kfree(port);
-}
-
-/**
* sel_netport_hashfn - Hashing function for the port table
* @pnum: port number
*
@@ -142,7 +126,7 @@ static void sel_netport_insert(struct sel_netport *port)
rcu_dereference(sel_netport_hash[idx].list.prev),
struct sel_netport, list);
list_del_rcu(&tail->list);
- call_rcu(&tail->rcu, sel_netport_free);
+ kfree_rcu(tail, rcu);
} else
sel_netport_hash[idx].size++;
}
@@ -241,7 +225,7 @@ static void sel_netport_flush(void)
list_for_each_entry_safe(port, port_tmp,
&sel_netport_hash[idx].list, list) {
list_del_rcu(&port->list);
- call_rcu(&port->rcu, sel_netport_free);
+ kfree_rcu(port, rcu);
}
sel_netport_hash[idx].size = 0;
}
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