Patch "netfilter: nft_set_pipapo: add helper to release pcpu scratch area" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    netfilter: nft_set_pipapo: add helper to release pcpu scratch area

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     netfilter-nft_set_pipapo-add-helper-to-release-pcpu-.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 34366fb46184dec6471229babb6438ce93a39a20
Author: Florian Westphal <fw@xxxxxxxxx>
Date:   Wed Feb 7 21:52:47 2024 +0100

    netfilter: nft_set_pipapo: add helper to release pcpu scratch area
    
    [ Upstream commit 47b1c03c3c1a119435480a1e73f27197dc59131d ]
    
    After next patch simple kfree() is not enough anymore, so add
    a helper for it.
    
    Reviewed-by: Stefano Brivio <sbrivio@xxxxxxxxxx>
    Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
    Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
    Stable-dep-of: 5a8cdf6fd860 ("netfilter: nft_set_pipapo: remove scratch_aligned pointer")
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c
index fbd0dbf9b965..977bf724fb7e 100644
--- a/net/netfilter/nft_set_pipapo.c
+++ b/net/netfilter/nft_set_pipapo.c
@@ -1101,6 +1101,24 @@ static void pipapo_map(struct nft_pipapo_match *m,
 		f->mt[map[i].to + j].e = e;
 }
 
+/**
+ * pipapo_free_scratch() - Free per-CPU map at original (not aligned) address
+ * @m:		Matching data
+ * @cpu:	CPU number
+ */
+static void pipapo_free_scratch(const struct nft_pipapo_match *m, unsigned int cpu)
+{
+	struct nft_pipapo_scratch *s;
+	void *mem;
+
+	s = *per_cpu_ptr(m->scratch, cpu);
+	if (!s)
+		return;
+
+	mem = s;
+	kfree(mem);
+}
+
 /**
  * pipapo_realloc_scratch() - Reallocate scratch maps for partial match results
  * @clone:	Copy of matching data with pending insertions and deletions
@@ -1133,7 +1151,7 @@ static int pipapo_realloc_scratch(struct nft_pipapo_match *clone,
 			return -ENOMEM;
 		}
 
-		kfree(*per_cpu_ptr(clone->scratch, i));
+		pipapo_free_scratch(clone, i);
 
 		*per_cpu_ptr(clone->scratch, i) = scratch;
 
@@ -1359,7 +1377,7 @@ static struct nft_pipapo_match *pipapo_clone(struct nft_pipapo_match *old)
 	}
 out_scratch_realloc:
 	for_each_possible_cpu(i)
-		kfree(*per_cpu_ptr(new->scratch, i));
+		pipapo_free_scratch(new, i);
 #ifdef NFT_PIPAPO_ALIGN
 	free_percpu(new->scratch_aligned);
 #endif
@@ -1647,7 +1665,7 @@ static void pipapo_free_match(struct nft_pipapo_match *m)
 	int i;
 
 	for_each_possible_cpu(i)
-		kfree(*per_cpu_ptr(m->scratch, i));
+		pipapo_free_scratch(m, i);
 
 #ifdef NFT_PIPAPO_ALIGN
 	free_percpu(m->scratch_aligned);
@@ -2249,7 +2267,7 @@ static void nft_pipapo_destroy(const struct nft_ctx *ctx,
 		free_percpu(m->scratch_aligned);
 #endif
 		for_each_possible_cpu(cpu)
-			kfree(*per_cpu_ptr(m->scratch, cpu));
+			pipapo_free_scratch(m, cpu);
 		free_percpu(m->scratch);
 		pipapo_free_fields(m);
 		kfree(m);
@@ -2266,7 +2284,7 @@ static void nft_pipapo_destroy(const struct nft_ctx *ctx,
 		free_percpu(priv->clone->scratch_aligned);
 #endif
 		for_each_possible_cpu(cpu)
-			kfree(*per_cpu_ptr(priv->clone->scratch, cpu));
+			pipapo_free_scratch(priv->clone, cpu);
 		free_percpu(priv->clone->scratch);
 
 		pipapo_free_fields(priv->clone);