Since SLOB was removed, it is not necessary to use call_rcu when the callback only performs kmem_cache_free. Use kfree_rcu() directly. The changes were done using the following Coccinelle semantic patch. This semantic patch is designed to ignore cases where the callback function is used in another way. // <smpl> @r@ expression e; local idexpression e2; identifier cb,f; position p; @@ ( call_rcu(...,e2) | call_rcu(&e->f,cb@p) ) @r1@ type T; identifier x,r.cb; @@ cb(...) { ( kmem_cache_free(...); | T x = ...; kmem_cache_free(...,x); | T x; x = ...; kmem_cache_free(...,x); ) } @s depends on r1@ position p != r.p; identifier r.cb; @@ cb@p @script:ocaml@ cb << r.cb; p << s.p; @@ Printf.eprintf "Other use of %s at %s:%d\n" cb (List.hd p).file (List.hd p).line @depends on r1 && !s@ expression e; identifier r.cb,f; position r.p; @@ - call_rcu(&e->f,cb@p) + kfree_rcu(e,f) @r1a depends on !s@ type T; identifier x,r.cb; @@ - cb(...) { ( - kmem_cache_free(...); | - T x = ...; - kmem_cache_free(...,x); | - T x; - x = ...; - kmem_cache_free(...,x); ) - } // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxxx> Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx> --- arch/powerpc/kvm/book3s_mmu_hpte.c | 8 +------- block/blk-ioc.c | 9 +-------- drivers/net/wireguard/allowedips.c | 9 ++------- fs/ecryptfs/dentry.c | 8 +------- fs/nfsd/nfs4state.c | 9 +-------- fs/tracefs/inode.c | 10 +--------- kernel/time/posix-timers.c | 9 +-------- kernel/workqueue.c | 8 +------- net/bridge/br_fdb.c | 9 +-------- net/can/gw.c | 13 +++---------- net/ipv4/fib_trie.c | 8 +------- net/ipv4/inetpeer.c | 9 ++------- net/ipv6/ip6_fib.c | 9 +-------- net/ipv6/xfrm6_tunnel.c | 8 +------- net/kcm/kcmsock.c | 10 +--------- net/netfilter/nf_conncount.c | 10 +--------- net/netfilter/nf_conntrack_expect.c | 10 +--------- net/netfilter/xt_hashlimit.c | 9 +-------- 18 files changed, 22 insertions(+), 143 deletions(-)