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>
Showing the changes to kernel/workqueue.c (1 of 1 file). Show all
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| @@ -5022,12 +5022,6 @@ fail: · 5021 unmodified lines | |||
| 5022 | return NULL; | 5022 | return NULL; |
| 5023 | } | 5023 | } |
| 5024 | 5024 | ||
| 5025 | static void rcu_free_pwq(struct rcu_head *rcu) | ||
| 5026 | { | ||
| 5027 | kmem_cache_free(pwq_cache, | ||
| 5028 | container_of(rcu, struct pool_workqueue, rcu)); | ||
| 5029 | } | ||
| 5030 | |||
| 5031 | /* | 5025 | /* |
| 5032 | * Scheduled on pwq_release_worker by put_pwq() when an unbound pwq hits zero | 5026 | * Scheduled on pwq_release_worker by put_pwq() when an unbound pwq hits zero |
| 5033 | * refcnt and needs to be destroyed. | 5027 | * refcnt and needs to be destroyed. |
| @@ -5073,7 +5067,7 @@ static void pwq_release_workfn(struct kthread_work *work) · 39 unmodified lines | |||
| 5073 | raw_spin_unlock_irq(&nna->lock); | 5067 | raw_spin_unlock_irq(&nna->lock); |
| 5074 | } | 5068 | } |
| 5075 | 5069 | ||
| 5076 | call_rcu(&pwq->rcu, rcu_free_pwq); | 5070 | kfree_rcu(pwq, rcu); |
| 5077 | 5071 | ||
| 5078 | /* | 5072 | /* |
| 5079 | * If we're the last pwq going away, @wq is already dead and no one | 5073 | * If we're the last pwq going away, @wq is already dead and no one |