[PATCH 00/17] replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[PATCH 00/17] replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Julia Lawall]

Since SLOB was removed and since
commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
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>
#spatch --all-includes --include-headers

@r@
expression e;
local idexpression e2;
identifier cb,f,g;
position p;
@@

(
call_rcu(...,e2)
|
call_rcu(&e->f,cb@p)
|
call_rcu(&e->f.g,cb@p)
)

@r1@
type T,T1;
identifier x,r.cb;
@@

 cb(...) {
(
   kmem_cache_free(...);
|
   T x = ...;
   kmem_cache_free(...,(T1)x);
|
   T x;
   x = ...;
   kmem_cache_free(...,(T1)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,g;
position r.p;
@@

(
- call_rcu(&e->f,cb@p)
+ kfree_rcu(e,f)
|
- call_rcu(&e->f.g,cb@p)
+ kfree_rcu(e,f.g)
)

@r1a depends on !s@
type T,T1;
identifier x,r.cb;
@@

- cb(...) {
(
-  kmem_cache_free(...);
|
-  T x = ...;
-  kmem_cache_free(...,(T1)x);
|
-  T x;
-  x = ...;
-  kmem_cache_free(...,(T1)x);
)
- }

@r2 depends on !r1@
identifier r.cb;
@@

cb(...) {
 ...
}

@script:ocaml depends on !r1 && !r2@
cb << r.cb;
@@

Printf.eprintf "need definition for %s\n" cb
// </smpl>

---

 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 ------
 kernel/time/posix-timers.c          |    9 ------
 net/batman-adv/translation-table.c  |   47 ++----------------------------------
 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 ------
 17 files changed, 23 insertions(+), 171 deletions(-)

[PATCH 15/17] netfilter: nf_conncount: replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Julia Lawall]

Since SLOB was removed and since
commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
it is not necessary to use call_rcu when the callback only performs
kmem_cache_free. Use kfree_rcu() directly.

The changes were made using Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

---
 net/netfilter/nf_conncount.c |   10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/net/netfilter/nf_conncount.c b/net/netfilter/nf_conncount.c
index 4890af4dc263..6a7a6c2d6ebc 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);
 	}

[PATCH 16/17] netfilter: expect: replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Julia Lawall]

Since SLOB was removed and since
commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
it is not necessary to use call_rcu when the callback only performs
kmem_cache_free. Use kfree_rcu() directly.

The changes were made using Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

---
 net/netfilter/nf_conntrack_expect.c |   10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

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);
 

[PATCH 17/17] netfilter: xt_hashlimit: replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Julia Lawall]

Since SLOB was removed and since
commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
it is not necessary to use call_rcu when the callback only performs
kmem_cache_free. Use kfree_rcu() directly.

The changes were made using Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

---
 net/netfilter/xt_hashlimit.c |    9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

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);

Re: (subset) [PATCH 00/17] replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Jens Axboe]

On Sun, 13 Oct 2024 22:16:47 +0200, Julia Lawall wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> 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.
> 
> [...]

Applied, thanks!

[09/17] block: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
        commit: 7a9b197adbafa9d6d1a79a0633607b78b1adef82

Best regards,
-- 
Jens Axboe

Re: [PATCH 00/17] replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Paul E. McKenney]

On Sun, Oct 13, 2024 at 10:16:47PM +0200, Julia Lawall wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> 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.

For the series:

Acked-by: Paul E. McKenney <paulmck@kernel.org>

> // <smpl>
> #spatch --all-includes --include-headers
> 
> @r@
> expression e;
> local idexpression e2;
> identifier cb,f,g;
> position p;
> @@
> 
> (
> call_rcu(...,e2)
> |
> call_rcu(&e->f,cb@p)
> |
> call_rcu(&e->f.g,cb@p)
> )
> 
> @r1@
> type T,T1;
> identifier x,r.cb;
> @@
> 
>  cb(...) {
> (
>    kmem_cache_free(...);
> |
>    T x = ...;
>    kmem_cache_free(...,(T1)x);
> |
>    T x;
>    x = ...;
>    kmem_cache_free(...,(T1)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,g;
> position r.p;
> @@
> 
> (
> - call_rcu(&e->f,cb@p)
> + kfree_rcu(e,f)
> |
> - call_rcu(&e->f.g,cb@p)
> + kfree_rcu(e,f.g)
> )
> 
> @r1a depends on !s@
> type T,T1;
> identifier x,r.cb;
> @@
> 
> - cb(...) {
> (
> -  kmem_cache_free(...);
> |
> -  T x = ...;
> -  kmem_cache_free(...,(T1)x);
> |
> -  T x;
> -  x = ...;
> -  kmem_cache_free(...,(T1)x);
> )
> - }
> 
> @r2 depends on !r1@
> identifier r.cb;
> @@
> 
> cb(...) {
>  ...
> }
> 
> @script:ocaml depends on !r1 && !r2@
> cb << r.cb;
> @@
> 
> Printf.eprintf "need definition for %s\n" cb
> // </smpl>
> 
> ---
> 
>  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 ------
>  kernel/time/posix-timers.c          |    9 ------
>  net/batman-adv/translation-table.c  |   47 ++----------------------------------
>  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 ------
>  17 files changed, 23 insertions(+), 171 deletions(-)

Re: [PATCH 00/17] replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Vlastimil Babka]

On 10/13/24 22:16, Julia Lawall wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> 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.

Thanks, LGTM!

For the series:

Acked-by: Vlastimil Babka <vbabka@suse.cz>

Re: [PATCH 00/17] replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Pablo Neira Ayuso]

On Sun, Oct 13, 2024 at 10:16:47PM +0200, Julia Lawall wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> it is not necessary to use call_rcu when the callback only performs
> kmem_cache_free. Use kfree_rcu() directly.

Applied and squashed into single patch for netfilter these patches:

[17/17] netfilter: xt_hashlimit: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
[16/17] netfilter: expect: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
[15/17] netfilter: nf_conncount: replace call_rcu by kfree_rcu for simple kmem_cache_free callback

this update is now flying to net-next.

Thanks

Re: [PATCH 00/17] replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Simon Wunderlich <sw@simonwunderlich.de>:

On Sun, 13 Oct 2024 22:16:47 +0200 you wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> 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.
> 
> [...]

Here is the summary with links:
  - [01/17] wireguard: allowedips: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [02/17] ipv4: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [03/17] inetpeer: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [04/17] ipv6: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [05/17] xfrm6_tunnel: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [06/17] batman-adv: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    https://git.kernel.org/netdev/net-next/c/356c81b6c494
  - [08/17] net: bridge: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [10/17] can: gw: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [14/17] kcm: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [15/17] netfilter: nf_conncount: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [16/17] netfilter: expect: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [17/17] netfilter: xt_hashlimit: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH 00/17] replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Sun, 13 Oct 2024 22:16:47 +0200 you wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> 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.
> 
> [...]

Here is the summary with links:
  - [01/17] wireguard: allowedips: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [02/17] ipv4: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    https://git.kernel.org/netdev/net-next/c/497e17d80759
  - [03/17] inetpeer: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    https://git.kernel.org/netdev/net-next/c/bb5810d4236b
  - [04/17] ipv6: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    https://git.kernel.org/netdev/net-next/c/85e48bcf294c
  - [05/17] xfrm6_tunnel: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [06/17] batman-adv: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [08/17] net: bridge: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    https://git.kernel.org/netdev/net-next/c/4ac64e570c33
  - [10/17] can: gw: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [14/17] kcm: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    https://git.kernel.org/netdev/net-next/c/7bb3ecbc2b6b
  - [15/17] netfilter: nf_conncount: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [16/17] netfilter: expect: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)
  - [17/17] netfilter: xt_hashlimit: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
    (no matching commit)

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH 16/17] netfilter: expect: replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Uladzislau Rezki]

On Sun, Oct 13, 2024 at 10:17:03PM +0200, Julia Lawall wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> it is not necessary to use call_rcu when the callback only performs
> kmem_cache_free. Use kfree_rcu() directly.
> 
> The changes were made using Coccinelle.
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
> 
> ---
>  net/netfilter/nf_conntrack_expect.c |   10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
> 
> 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);
>  
> 
> 
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

--
Uladzislau Rezki

Re: [PATCH 15/17] netfilter: nf_conncount: replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Uladzislau Rezki]

On Sun, Oct 13, 2024 at 10:17:02PM +0200, Julia Lawall wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> it is not necessary to use call_rcu when the callback only performs
> kmem_cache_free. Use kfree_rcu() directly.
> 
> The changes were made using Coccinelle.
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
> 
> ---
>  net/netfilter/nf_conncount.c |   10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/net/netfilter/nf_conncount.c b/net/netfilter/nf_conncount.c
> index 4890af4dc263..6a7a6c2d6ebc 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);
>  	}
> 
> 
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

--
Uladzislau Rezki

Re: [PATCH 17/17] netfilter: xt_hashlimit: replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Uladzislau Rezki]

On Sun, Oct 13, 2024 at 10:17:04PM +0200, Julia Lawall wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> it is not necessary to use call_rcu when the callback only performs
> kmem_cache_free. Use kfree_rcu() directly.
> 
> The changes were made using Coccinelle.
> 
> Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
> 
> ---
>  net/netfilter/xt_hashlimit.c |    9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
> 
> 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);
> 
> 
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>

--
Uladzislau Rezki

Re: (subset) [PATCH 00/17] replace call_rcu by kfree_rcu for simple kmem_cache_free callback

[Michael Ellerman]

On Sun, 13 Oct 2024 22:16:47 +0200, Julia Lawall wrote:
> Since SLOB was removed and since
> commit 6c6c47b063b5 ("mm, slab: call kvfree_rcu_barrier() from kmem_cache_destroy()"),
> 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.
> 
> [...]

Applied to powerpc/topic/ppc-kvm.

[13/17] KVM: PPC: replace call_rcu by kfree_rcu for simple kmem_cache_free callback
        https://git.kernel.org/powerpc/c/1db6a4e8a3fc8ccaa4690272935e02831dc6d40d

cheers