Commit 456010c8 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Florian Westphal
Browse files

netfilter: nft_set_pipapo: Use nested-BH locking for nft_pipapo_scratch 



nft_pipapo_scratch is a per-CPU variable and relies on disabled BH for
its locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT
this data structure requires explicit locking.

Add a local_lock_t to the data structure and use local_lock_nested_bh() for
locking. This change adds only lockdep coverage and does not alter the
functional behaviour for !PREEMPT_RT.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
parent 6aa67d57

net/netfilter/nft_set_pipapo.c

+5 −0
Original line number Diff line number Diff line
@@ -429,6 +429,7 @@ static struct nft_pipapo_elem *pipapo_get_slow(const struct nft_pipapo_match *m, 
	scratch = *raw_cpu_ptr(m->scratch);

	if (unlikely(!scratch))

		goto out;

	__local_lock_nested_bh(&scratch->bh_lock);



	map_index = scratch->map_index;
@@ -465,6 +466,7 @@ static struct nft_pipapo_elem *pipapo_get_slow(const struct nft_pipapo_match *m, 
				  last);

		if (b < 0) {

			scratch->map_index = map_index;

			__local_unlock_nested_bh(&scratch->bh_lock);

			local_bh_enable();



			return NULL;
@@ -484,6 +486,7 @@ static struct nft_pipapo_elem *pipapo_get_slow(const struct nft_pipapo_match *m, 
			 * *next* bitmap (not initial) for the next packet.

			 */

			scratch->map_index = map_index;

			__local_unlock_nested_bh(&scratch->bh_lock);

			local_bh_enable();

			return e;

		}
@@ -498,6 +501,7 @@ static struct nft_pipapo_elem *pipapo_get_slow(const struct nft_pipapo_match *m, 
		data += NFT_PIPAPO_GROUPS_PADDING(f);

	}



	__local_unlock_nested_bh(&scratch->bh_lock);

out:

	local_bh_enable();

	return NULL;
@@ -1215,6 +1219,7 @@ static int pipapo_realloc_scratch(struct nft_pipapo_match *clone, 
		}



		pipapo_free_scratch(clone, i);

		local_lock_init(&scratch->bh_lock);

		*per_cpu_ptr(clone->scratch, i) = scratch;

	}

net/netfilter/nft_set_pipapo.h

+2 −0
Original line number Diff line number Diff line
@@ -124,10 +124,12 @@ struct nft_pipapo_field { 


/**

 * struct nft_pipapo_scratch - percpu data used for lookup and matching

 * @bh_lock:    PREEMPT_RT local spinlock

 * @map_index:	Current working bitmap index, toggled between field matches

 * @__map:	store partial matching results during lookup

 */

struct nft_pipapo_scratch {

	local_lock_t bh_lock;

	u8 map_index;

	unsigned long __map[];

};

net/netfilter/nft_set_pipapo_avx2.c

+4 −0
Original line number Diff line number Diff line
@@ -1163,6 +1163,7 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m, 
	if (unlikely(!scratch))

		return NULL;



	__local_lock_nested_bh(&scratch->bh_lock);

	map_index = scratch->map_index;

	map = NFT_PIPAPO_LT_ALIGN(&scratch->__map[0]);

	res  = map + (map_index ? m->bsize_max : 0);
@@ -1228,6 +1229,7 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m, 
		if (ret < 0) {

			scratch->map_index = map_index;

			kernel_fpu_end();

			__local_unlock_nested_bh(&scratch->bh_lock);

			return NULL;

		}
@@ -1241,6 +1243,7 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m, 


			scratch->map_index = map_index;

			kernel_fpu_end();

			__local_unlock_nested_bh(&scratch->bh_lock);

			return e;

		}
@@ -1250,6 +1253,7 @@ struct nft_pipapo_elem *pipapo_get_avx2(const struct nft_pipapo_match *m, 
	}



	kernel_fpu_end();

	__local_unlock_nested_bh(&scratch->bh_lock);

	return NULL;

}