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> --- block/blk-ioc.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) 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); } /*