Re: [cocci] patch idea: convert trivial call_rcu users to kfree_rcu

[Julia Lawall <julia.lawall@inria.fr>]

Here are the changes proposed by Coccinelle.

I didn't succeed to compile the powerpc code, but the rest has been
compile tested.

julia

commit 1881f31fe3ad693d07ecff45985dd0e87534923f
Author: Julia Lawall <Julia.Lawall@inria.fr>
Date:   Wed May 29 18:54:41 2024 +0200

    misc

diff --git a/arch/powerpc/kvm/book3s_mmu_hpte.c b/arch/powerpc/kvm/book3s_mmu_hpte.c
index ce79ac33e8d3..d904e13e069b 100644
--- a/arch/powerpc/kvm/book3s_mmu_hpte.c
+++ b/arch/powerpc/kvm/book3s_mmu_hpte.c
@@ -92,12 +92,6 @@ void kvmppc_mmu_hpte_cache_map(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
 	spin_unlock(&vcpu3s->mmu_lock);
 }

-static void free_pte_rcu(struct rcu_head *head)
-{
-	struct hpte_cache *pte = container_of(head, struct hpte_cache, rcu_head);
-	kmem_cache_free(hpte_cache, pte);
-}
-
 static void invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)
 {
 	struct kvmppc_vcpu_book3s *vcpu3s = to_book3s(vcpu);
@@ -126,7 +120,7 @@ static void invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte)

 	spin_unlock(&vcpu3s->mmu_lock);

-	call_rcu(&pte->rcu_head, free_pte_rcu);
+	kfree_rcu(pte, rcu_head);
 }

 static void kvmppc_mmu_pte_flush_all(struct kvm_vcpu *vcpu)
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index 25dd4db11121..ce82770c72ab 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -32,13 +32,6 @@ static void get_io_context(struct io_context *ioc)
 	atomic_long_inc(&ioc->refcount);
 }

-static void icq_free_icq_rcu(struct rcu_head *head)
-{
-	struct io_cq *icq = container_of(head, struct io_cq, __rcu_head);
-
-	kmem_cache_free(icq->__rcu_icq_cache, icq);
-}
-
 /*
  * Exit an icq. Called with ioc locked for blk-mq, and with both ioc
  * and queue locked for legacy.
@@ -102,7 +95,7 @@ static void ioc_destroy_icq(struct io_cq *icq)
 	 */
 	icq->__rcu_icq_cache = et->icq_cache;
 	icq->flags |= ICQ_DESTROYED;
-	call_rcu(&icq->__rcu_head, icq_free_icq_rcu);
+	kfree_rcu(icq, __rcu_head);
 }

 /*
diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c
index 0ba714ca5185..e4e1638fce1b 100644
--- a/drivers/net/wireguard/allowedips.c
+++ b/drivers/net/wireguard/allowedips.c
@@ -48,11 +48,6 @@ static void push_rcu(struct allowedips_node **stack,
 	}
 }

-static void node_free_rcu(struct rcu_head *rcu)
-{
-	kmem_cache_free(node_cache, container_of(rcu, struct allowedips_node, rcu));
-}
-
 static void root_free_rcu(struct rcu_head *rcu)
 {
 	struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_DEPTH] = {
@@ -330,13 +325,13 @@ void wg_allowedips_remove_by_peer(struct allowedips *table,
 			child = rcu_dereference_protected(
 					parent->bit[!(node->parent_bit_packed & 1)],
 					lockdep_is_held(lock));
-		call_rcu(&node->rcu, node_free_rcu);
+		kfree_rcu(node, rcu);
 		if (!free_parent)
 			continue;
 		if (child)
 			child->parent_bit_packed = parent->parent_bit_packed;
 		*(struct allowedips_node **)(parent->parent_bit_packed & ~3UL) = child;
-		call_rcu(&parent->rcu, node_free_rcu);
+		kfree_rcu(parent, rcu);
 	}
 }

diff --git a/fs/ecryptfs/dentry.c b/fs/ecryptfs/dentry.c
index acaa0825e9bb..49d626ff33a9 100644
--- a/fs/ecryptfs/dentry.c
+++ b/fs/ecryptfs/dentry.c
@@ -51,12 +51,6 @@ static int ecryptfs_d_revalidate(struct dentry *dentry, unsigned int flags)

 struct kmem_cache *ecryptfs_dentry_info_cache;

-static void ecryptfs_dentry_free_rcu(struct rcu_head *head)
-{
-	kmem_cache_free(ecryptfs_dentry_info_cache,
-		container_of(head, struct ecryptfs_dentry_info, rcu));
-}
-
 /**
  * ecryptfs_d_release
  * @dentry: The ecryptfs dentry
@@ -68,7 +62,7 @@ static void ecryptfs_d_release(struct dentry *dentry)
 	struct ecryptfs_dentry_info *p = dentry->d_fsdata;
 	if (p) {
 		path_put(&p->lower_path);
-		call_rcu(&p->rcu, ecryptfs_dentry_free_rcu);
+		kfree_rcu(p, rcu);
 	}
 }

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a20c2c9d7d45..eba5083504c7 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -571,13 +571,6 @@ opaque_hashval(const void *ptr, int nbytes)
 	return x;
 }

-static void nfsd4_free_file_rcu(struct rcu_head *rcu)
-{
-	struct nfs4_file *fp = container_of(rcu, struct nfs4_file, fi_rcu);
-
-	kmem_cache_free(file_slab, fp);
-}
-
 void
 put_nfs4_file(struct nfs4_file *fi)
 {
@@ -585,7 +578,7 @@ put_nfs4_file(struct nfs4_file *fi)
 		nfsd4_file_hash_remove(fi);
 		WARN_ON_ONCE(!list_empty(&fi->fi_clnt_odstate));
 		WARN_ON_ONCE(!list_empty(&fi->fi_delegations));
-		call_rcu(&fi->fi_rcu, nfsd4_free_file_rcu);
+		kfree_rcu(fi, fi_rcu);
 	}
 }

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 7c29f4afc23d..338c52168e61 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -53,14 +53,6 @@ static struct inode *tracefs_alloc_inode(struct super_block *sb)
 	return &ti->vfs_inode;
 }

-static void tracefs_free_inode_rcu(struct rcu_head *rcu)
-{
-	struct tracefs_inode *ti;
-
-	ti = container_of(rcu, struct tracefs_inode, rcu);
-	kmem_cache_free(tracefs_inode_cachep, ti);
-}
-
 static void tracefs_free_inode(struct inode *inode)
 {
 	struct tracefs_inode *ti = get_tracefs(inode);
@@ -70,7 +62,7 @@ static void tracefs_free_inode(struct inode *inode)
 	list_del_rcu(&ti->list);
 	spin_unlock_irqrestore(&tracefs_inode_lock, flags);

-	call_rcu(&ti->rcu, tracefs_free_inode_rcu);
+	kfree_rcu(ti, rcu);
 }

 static ssize_t default_read_file(struct file *file, char __user *buf,
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index b924f0f096fa..bad5db979664 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -412,18 +412,11 @@ static struct k_itimer * alloc_posix_timer(void)
 	return tmr;
 }

-static void k_itimer_rcu_free(struct rcu_head *head)
-{
-	struct k_itimer *tmr = container_of(head, struct k_itimer, rcu);
-
-	kmem_cache_free(posix_timers_cache, tmr);
-}
-
 static void posix_timer_free(struct k_itimer *tmr)
 {
 	put_pid(tmr->it_pid);
 	sigqueue_free(tmr->sigq);
-	call_rcu(&tmr->rcu, k_itimer_rcu_free);
+	kfree_rcu(tmr, rcu);
 }

 static void posix_timer_unhash_and_free(struct k_itimer *tmr)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 003474c9a77d..367fc459cbd2 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -5022,12 +5022,6 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
 	return NULL;
 }

-static void rcu_free_pwq(struct rcu_head *rcu)
-{
-	kmem_cache_free(pwq_cache,
-			container_of(rcu, struct pool_workqueue, rcu));
-}
-
 /*
  * Scheduled on pwq_release_worker by put_pwq() when an unbound pwq hits zero
  * refcnt and needs to be destroyed.
@@ -5073,7 +5067,7 @@ static void pwq_release_workfn(struct kthread_work *work)
 		raw_spin_unlock_irq(&nna->lock);
 	}

-	call_rcu(&pwq->rcu, rcu_free_pwq);
+	kfree_rcu(pwq, rcu);

 	/*
 	 * If we're the last pwq going away, @wq is already dead and no one
diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c
index c77591e63841..6d04b48f7e2c 100644
--- a/net/bridge/br_fdb.c
+++ b/net/bridge/br_fdb.c
@@ -73,13 +73,6 @@ static inline int has_expired(const struct net_bridge *br,
 	       time_before_eq(fdb->updated + hold_time(br), jiffies);
 }

-static void fdb_rcu_free(struct rcu_head *head)
-{
-	struct net_bridge_fdb_entry *ent
-		= container_of(head, struct net_bridge_fdb_entry, rcu);
-	kmem_cache_free(br_fdb_cache, ent);
-}
-
 static int fdb_to_nud(const struct net_bridge *br,
 		      const struct net_bridge_fdb_entry *fdb)
 {
@@ -329,7 +322,7 @@ static void fdb_delete(struct net_bridge *br, struct net_bridge_fdb_entry *f,
 	if (test_and_clear_bit(BR_FDB_DYNAMIC_LEARNED, &f->flags))
 		atomic_dec(&br->fdb_n_learned);
 	fdb_notify(br, f, RTM_DELNEIGH, swdev_notify);
-	call_rcu(&f->rcu, fdb_rcu_free);
+	kfree_rcu(f, rcu);
 }

 /* Delete a local entry if no other port had the same address.
diff --git a/net/can/gw.c b/net/can/gw.c
index 37528826935e..ffb9870e2d01 100644
--- a/net/can/gw.c
+++ b/net/can/gw.c
@@ -577,13 +577,6 @@ static inline void cgw_unregister_filter(struct net *net, struct cgw_job *gwj)
 			  gwj->ccgw.filter.can_mask, can_can_gw_rcv, gwj);
 }

-static void cgw_job_free_rcu(struct rcu_head *rcu_head)
-{
-	struct cgw_job *gwj = container_of(rcu_head, struct cgw_job, rcu);
-
-	kmem_cache_free(cgw_cache, gwj);
-}
-
 static int cgw_notifier(struct notifier_block *nb,
 			unsigned long msg, void *ptr)
 {
@@ -603,7 +596,7 @@ static int cgw_notifier(struct notifier_block *nb,
 			if (gwj->src.dev == dev || gwj->dst.dev == dev) {
 				hlist_del(&gwj->list);
 				cgw_unregister_filter(net, gwj);
-				call_rcu(&gwj->rcu, cgw_job_free_rcu);
+				kfree_rcu(gwj, rcu);
 			}
 		}
 	}
@@ -1168,7 +1161,7 @@ static void cgw_remove_all_jobs(struct net *net)
 	hlist_for_each_entry_safe(gwj, nx, &net->can.cgw_list, list) {
 		hlist_del(&gwj->list);
 		cgw_unregister_filter(net, gwj);
-		call_rcu(&gwj->rcu, cgw_job_free_rcu);
+		kfree_rcu(gwj, rcu);
 	}
 }

@@ -1236,7 +1229,7 @@ static int cgw_remove_job(struct sk_buff *skb, struct nlmsghdr *nlh,

 		hlist_del(&gwj->list);
 		cgw_unregister_filter(net, gwj);
-		call_rcu(&gwj->rcu, cgw_job_free_rcu);
+		kfree_rcu(gwj, rcu);
 		err = 0;
 		break;
 	}
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index f474106464d2..3ed92e583417 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -292,15 +292,9 @@ static const int inflate_threshold = 50;
 static const int halve_threshold_root = 15;
 static const int inflate_threshold_root = 30;

-static void __alias_free_mem(struct rcu_head *head)
-{
-	struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
-	kmem_cache_free(fn_alias_kmem, fa);
-}
-
 static inline void alias_free_mem_rcu(struct fib_alias *fa)
 {
-	call_rcu(&fa->rcu, __alias_free_mem);
+	kfree_rcu(fa, rcu);
 }

 #define TNODE_VMALLOC_MAX \
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 5bd759963451..5ab56f4cb529 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -128,11 +128,6 @@ static struct inet_peer *lookup(const struct inetpeer_addr *daddr,
 	return NULL;
 }

-static void inetpeer_free_rcu(struct rcu_head *head)
-{
-	kmem_cache_free(peer_cachep, container_of(head, struct inet_peer, rcu));
-}
-
 /* perform garbage collect on all items stacked during a lookup */
 static void inet_peer_gc(struct inet_peer_base *base,
 			 struct inet_peer *gc_stack[],
@@ -168,7 +163,7 @@ static void inet_peer_gc(struct inet_peer_base *base,
 		if (p) {
 			rb_erase(&p->rb_node, &base->rb_root);
 			base->total--;
-			call_rcu(&p->rcu, inetpeer_free_rcu);
+			kfree_rcu(p, rcu);
 		}
 	}
 }
@@ -242,7 +237,7 @@ void inet_putpeer(struct inet_peer *p)
 	WRITE_ONCE(p->dtime, (__u32)jiffies);

 	if (refcount_dec_and_test(&p->refcnt))
-		call_rcu(&p->rcu, inetpeer_free_rcu);
+		kfree_rcu(p, rcu);
 }
 EXPORT_SYMBOL_GPL(inet_putpeer);

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 31d77885bcae..bafc49de270e 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -198,16 +198,9 @@ static void node_free_immediate(struct net *net, struct fib6_node *fn)
 	net->ipv6.rt6_stats->fib_nodes--;
 }

-static void node_free_rcu(struct rcu_head *head)
-{
-	struct fib6_node *fn = container_of(head, struct fib6_node, rcu);
-
-	kmem_cache_free(fib6_node_kmem, fn);
-}
-
 static void node_free(struct net *net, struct fib6_node *fn)
 {
-	call_rcu(&fn->rcu, node_free_rcu);
+	kfree_rcu(fn, rcu);
 	net->ipv6.rt6_stats->fib_nodes--;
 }

diff --git a/net/ipv6/xfrm6_tunnel.c b/net/ipv6/xfrm6_tunnel.c
index bf140ef781c1..c3c893ddb6ee 100644
--- a/net/ipv6/xfrm6_tunnel.c
+++ b/net/ipv6/xfrm6_tunnel.c
@@ -178,12 +178,6 @@ __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr)
 }
 EXPORT_SYMBOL(xfrm6_tunnel_alloc_spi);

-static void x6spi_destroy_rcu(struct rcu_head *head)
-{
-	kmem_cache_free(xfrm6_tunnel_spi_kmem,
-			container_of(head, struct xfrm6_tunnel_spi, rcu_head));
-}
-
 static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
 {
 	struct xfrm6_tunnel_net *xfrm6_tn = xfrm6_tunnel_pernet(net);
@@ -200,7 +194,7 @@ static void xfrm6_tunnel_free_spi(struct net *net, xfrm_address_t *saddr)
 			if (refcount_dec_and_test(&x6spi->refcnt)) {
 				hlist_del_rcu(&x6spi->list_byaddr);
 				hlist_del_rcu(&x6spi->list_byspi);
-				call_rcu(&x6spi->rcu_head, x6spi_destroy_rcu);
+				kfree_rcu(x6spi, rcu_head);
 				break;
 			}
 		}
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 2f191e50d4fc..fbb730cd2d38 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1580,14 +1580,6 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 	return err;
 }

-static void free_mux(struct rcu_head *rcu)
-{
-	struct kcm_mux *mux = container_of(rcu,
-	    struct kcm_mux, rcu);
-
-	kmem_cache_free(kcm_muxp, mux);
-}
-
 static void release_mux(struct kcm_mux *mux)
 {
 	struct kcm_net *knet = mux->knet;
@@ -1615,7 +1607,7 @@ static void release_mux(struct kcm_mux *mux)
 	knet->count--;
 	mutex_unlock(&knet->mutex);

-	call_rcu(&mux->rcu, free_mux);
+	kfree_rcu(mux, rcu);
 }

 static void kcm_done(struct kcm_sock *kcm)
diff --git a/net/netfilter/nf_conncount.c b/net/netfilter/nf_conncount.c
index 8715617b02fe..587bfcb79723 100644
--- a/net/netfilter/nf_conncount.c
+++ b/net/netfilter/nf_conncount.c
@@ -275,14 +275,6 @@ bool nf_conncount_gc_list(struct net *net,
 }
 EXPORT_SYMBOL_GPL(nf_conncount_gc_list);

-static void __tree_nodes_free(struct rcu_head *h)
-{
-	struct nf_conncount_rb *rbconn;
-
-	rbconn = container_of(h, struct nf_conncount_rb, rcu_head);
-	kmem_cache_free(conncount_rb_cachep, rbconn);
-}
-
 /* caller must hold tree nf_conncount_locks[] lock */
 static void tree_nodes_free(struct rb_root *root,
 			    struct nf_conncount_rb *gc_nodes[],
@@ -295,7 +287,7 @@ static void tree_nodes_free(struct rb_root *root,
 		spin_lock(&rbconn->list.list_lock);
 		if (!rbconn->list.count) {
 			rb_erase(&rbconn->node, root);
-			call_rcu(&rbconn->rcu_head, __tree_nodes_free);
+			kfree_rcu(rbconn, rcu_head);
 		}
 		spin_unlock(&rbconn->list.list_lock);
 	}
diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c
index 21fa550966f0..9dcaef6f3663 100644
--- a/net/netfilter/nf_conntrack_expect.c
+++ b/net/netfilter/nf_conntrack_expect.c
@@ -367,18 +367,10 @@ void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class,
 }
 EXPORT_SYMBOL_GPL(nf_ct_expect_init);

-static void nf_ct_expect_free_rcu(struct rcu_head *head)
-{
-	struct nf_conntrack_expect *exp;
-
-	exp = container_of(head, struct nf_conntrack_expect, rcu);
-	kmem_cache_free(nf_ct_expect_cachep, exp);
-}
-
 void nf_ct_expect_put(struct nf_conntrack_expect *exp)
 {
 	if (refcount_dec_and_test(&exp->use))
-		call_rcu(&exp->rcu, nf_ct_expect_free_rcu);
+		kfree_rcu(exp, rcu);
 }
 EXPORT_SYMBOL_GPL(nf_ct_expect_put);

diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 0859b8f76764..c2b9b954eb53 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -256,18 +256,11 @@ dsthash_alloc_init(struct xt_hashlimit_htable *ht,
 	return ent;
 }

-static void dsthash_free_rcu(struct rcu_head *head)
-{
-	struct dsthash_ent *ent = container_of(head, struct dsthash_ent, rcu);
-
-	kmem_cache_free(hashlimit_cachep, ent);
-}
-
 static inline void
 dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
 {
 	hlist_del_rcu(&ent->node);
-	call_rcu(&ent->rcu, dsthash_free_rcu);
+	kfree_rcu(ent, rcu);
 	ht->count--;
 }
 static void htable_gc(struct work_struct *work);