Commit c0d63f30 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
Browse files

bpf: Add bpf_selem_free() 



This patch refactors the selem freeing logic into bpf_selem_free().
It is a preparation work for a later patch using
bpf_mem_cache_alloc/free. The other kfree(selem) cases
are also changed to bpf_selem_free(..., reuse_now = true).

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20230308065936.1550103-10-martin.lau@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent f8ccf30c

include/linux/bpf_local_storage.h

+4 −0
Original line number Diff line number Diff line
@@ -152,6 +152,10 @@ struct bpf_local_storage_elem * 
bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value,

		bool charge_mem, gfp_t gfp_flags);



void bpf_selem_free(struct bpf_local_storage_elem *selem,

		    struct bpf_local_storage_map *smap,

		    bool reuse_now);



int

bpf_local_storage_alloc(void *owner,

			struct bpf_local_storage_map *smap,

kernel/bpf/bpf_local_storage.c

+14 −7
Original line number Diff line number Diff line
@@ -125,6 +125,17 @@ static void bpf_selem_free_trace_rcu(struct rcu_head *rcu) 
		call_rcu(rcu, bpf_selem_free_rcu);

}



void bpf_selem_free(struct bpf_local_storage_elem *selem,

		    struct bpf_local_storage_map *smap,

		    bool reuse_now)

{

	bpf_obj_free_fields(smap->map.record, SDATA(selem)->data);

	if (!reuse_now)

		call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_trace_rcu);

	else

		call_rcu(&selem->rcu, bpf_selem_free_rcu);

}



/* local_storage->lock must be held and selem->local_storage == local_storage.

 * The caller must ensure selem->smap is still valid to be

 * dereferenced for its smap->elem_size and smap->cache_idx.
@@ -175,11 +186,7 @@ static bool bpf_selem_unlink_storage_nolock(struct bpf_local_storage *local_stor 
	    SDATA(selem))

		RCU_INIT_POINTER(local_storage->cache[smap->cache_idx], NULL);



	bpf_obj_free_fields(smap->map.record, SDATA(selem)->data);

	if (!reuse_now)

		call_rcu_tasks_trace(&selem->rcu, bpf_selem_free_trace_rcu);

	else

		call_rcu(&selem->rcu, bpf_selem_free_rcu);

	bpf_selem_free(selem, smap, reuse_now);



	if (rcu_access_pointer(local_storage->smap) == smap)

		RCU_INIT_POINTER(local_storage->smap, NULL);
@@ -423,7 +430,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, 


		err = bpf_local_storage_alloc(owner, smap, selem, gfp_flags);

		if (err) {

			kfree(selem);

			bpf_selem_free(selem, smap, true);

			mem_uncharge(smap, owner, smap->elem_size);

			return ERR_PTR(err);

		}
@@ -517,7 +524,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, 
	raw_spin_unlock_irqrestore(&local_storage->lock, flags);

	if (selem) {

		mem_uncharge(smap, owner, smap->elem_size);

		kfree(selem);

		bpf_selem_free(selem, smap, true);

	}

	return ERR_PTR(err);

}

net/core/bpf_sk_storage.c

+1 −1
Original line number Diff line number Diff line
@@ -197,7 +197,7 @@ int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk) 
		} else {

			ret = bpf_local_storage_alloc(newsk, smap, copy_selem, GFP_ATOMIC);

			if (ret) {

				kfree(copy_selem);

				bpf_selem_free(copy_selem, smap, true);

				atomic_sub(smap->elem_size,

					   &newsk->sk_omem_alloc);

				bpf_map_put(map);