[PATCH nf-next] netfilter: nft_set_pipapo_avx2: remove redundant loop in lookup_slow

[PATCH nf-next] netfilter: nft_set_pipapo_avx2: remove redundant loop in lookup_slow

[Florian Westphal]

nft_pipapo_avx2_lookup_slow will never be used in reality, because the
common sizes are handled by avx2 optimized versions.

However, nft_pipapo_avx2_lookup_slow loops over the data just like the
avx2 functions. BUT _slow doesn't need to do that:
  pipapo_and_field_buckets_() + pipapo_refill() already handle
  everyhing for us.

All other iterations boild down to 'x = x & x': Remove the loop.

Signed-off-by: Florian Westphal <fw@strlen.de>
---
 net/netfilter/nft_set_pipapo_avx2.c | 30 ++++++++---------------------
 1 file changed, 8 insertions(+), 22 deletions(-)

diff --git a/net/netfilter/nft_set_pipapo_avx2.c b/net/netfilter/nft_set_pipapo_avx2.c
index 7ff90325c97f..025f9ebb1ba2 100644
--- a/net/netfilter/nft_set_pipapo_avx2.c
+++ b/net/netfilter/nft_set_pipapo_avx2.c
@@ -1041,7 +1041,6 @@ static int nft_pipapo_avx2_lookup_8b_16(unsigned long *map, unsigned long *fill,
  * @map:	Previous match result, used as initial bitmap
  * @fill:	Destination bitmap to be filled with current match result
  * @f:		Field, containing lookup and mapping tables
- * @offset:	Ignore buckets before the given index, no bits are filled there
  * @pkt:	Packet data, pointer to input nftables register
  * @first:	If this is the first field, don't source previous result
  * @last:	Last field: stop at the first match and return bit index
@@ -1056,32 +1055,19 @@ static int nft_pipapo_avx2_lookup_8b_16(unsigned long *map, unsigned long *fill,
 static int nft_pipapo_avx2_lookup_slow(const struct nft_pipapo_match *mdata,
 					unsigned long *map, unsigned long *fill,
 					const struct nft_pipapo_field *f,
-					int offset, const u8 *pkt,
+					const u8 *pkt,
 					bool first, bool last)
 {
-	unsigned long bsize = f->bsize;
-	int i, ret = -1, b;
-
 	if (first)
 		pipapo_resmap_init(mdata, map);
 
-	for (i = offset; i < bsize; i++) {
-		if (f->bb == 8)
-			pipapo_and_field_buckets_8bit(f, map, pkt);
-		else
+	if (f->bb == 8)
+		pipapo_and_field_buckets_8bit(f, map, pkt);
+	else
 			pipapo_and_field_buckets_4bit(f, map, pkt);
-		NFT_PIPAPO_GROUP_BITS_ARE_8_OR_4;
-
-		b = pipapo_refill(map, bsize, f->rules, fill, f->mt, last);
-
-		if (last)
-			return b;
-
-		if (ret == -1)
-			ret = b / XSAVE_YMM_SIZE;
-	}
+	NFT_PIPAPO_GROUP_BITS_ARE_8_OR_4;
 
-	return ret;
+	return pipapo_refill(map, f->bsize, f->rules, fill, f->mt, last);
 }
 
 /**
@@ -1201,7 +1187,7 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m,
 				NFT_SET_PIPAPO_AVX2_LOOKUP(8, 16);
 			} else {
 				ret = nft_pipapo_avx2_lookup_slow(m, res, fill, f,
-								  ret, data,
+								  data,
 								  first, last);
 			}
 		} else {
@@ -1217,7 +1203,7 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m,
 				NFT_SET_PIPAPO_AVX2_LOOKUP(4, 32);
 			} else {
 				ret = nft_pipapo_avx2_lookup_slow(m, res, fill, f,
-								  ret, data,
+								  data,
 								  first, last);
 			}
 		}
-- 
2.52.0

Re: [PATCH nf-next] netfilter: nft_set_pipapo_avx2: remove redundant loop in lookup_slow

[Stefano Brivio]

On Wed, 18 Mar 2026 14:42:12 +0100
Florian Westphal <fw@strlen.de> wrote:

> nft_pipapo_avx2_lookup_slow will never be used in reality, because the
> common sizes are handled by avx2 optimized versions.
> 
> However, nft_pipapo_avx2_lookup_slow loops over the data just like the
> avx2 functions. BUT _slow doesn't need to do that:
>   pipapo_and_field_buckets_() + pipapo_refill() already handle
>   everyhing for us.

Ah, right, indeed.

> All other iterations boild down to 'x = x & x': Remove the loop.
> 
> Signed-off-by: Florian Westphal <fw@strlen.de>

Reviewed-by: Stefano Brivio <sbrivio@redhat.com>

-- 
Stefano