Commit e76a33e1 authored by Amery Hung's avatar Amery Hung Committed by Alexei Starovoitov
Browse files

bpf: Remove smap argument from bpf_selem_free() 



Since selem already saves a pointer to smap, use it instead of an
additional argument in bpf_selem_free(). This requires moving the
SDATA(selem)->smap assignment from bpf_selem_link_map() to
bpf_selem_alloc() since bpf_selem_free() may be called without the
selem being linked to smap in bpf_local_storage_update().

Signed-off-by: default avatarAmery Hung <ameryhung@gmail.com>
Reviewed-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20251114201329.3275875-3-ameryhung@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 0e854e55

include/linux/bpf_local_storage.h

+0 −1
Original line number Diff line number Diff line
@@ -187,7 +187,6 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, void *value, 
		bool swap_uptrs, gfp_t gfp_flags);



void bpf_selem_free(struct bpf_local_storage_elem *selem,

		    struct bpf_local_storage_map *smap,

		    bool reuse_now);



int

kernel/bpf/bpf_local_storage.c

+10 −9
Original line number Diff line number Diff line
@@ -97,6 +97,8 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner, 
	}



	if (selem) {

		RCU_INIT_POINTER(SDATA(selem)->smap, smap);



		if (value) {

			/* No need to call check_and_init_map_value as memory is zero init */

			copy_map_value(&smap->map, SDATA(selem)->data, value);
@@ -227,9 +229,12 @@ static void bpf_selem_free_trace_rcu(struct rcu_head *rcu) 
}



void bpf_selem_free(struct bpf_local_storage_elem *selem,

		    struct bpf_local_storage_map *smap,

		    bool reuse_now)

{

	struct bpf_local_storage_map *smap;



	smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held());



	if (!smap->bpf_ma) {

		/* Only task storage has uptrs and task storage

		 * has moved to bpf_mem_alloc. Meaning smap->bpf_ma == true
@@ -263,7 +268,6 @@ void bpf_selem_free(struct bpf_local_storage_elem *selem, 
static void bpf_selem_free_list(struct hlist_head *list, bool reuse_now)

{

	struct bpf_local_storage_elem *selem;

	struct bpf_local_storage_map *smap;

	struct hlist_node *n;



	/* The "_safe" iteration is needed.
@@ -271,10 +275,8 @@ static void bpf_selem_free_list(struct hlist_head *list, bool reuse_now) 
	 * but bpf_selem_free will use the selem->rcu_head

	 * which is union-ized with the selem->free_node.

	 */

	hlist_for_each_entry_safe(selem, n, list, free_node) {

		smap = rcu_dereference_check(SDATA(selem)->smap, bpf_rcu_lock_held());

		bpf_selem_free(selem, smap, reuse_now);

	}

	hlist_for_each_entry_safe(selem, n, list, free_node)

		bpf_selem_free(selem, reuse_now);

}



/* local_storage->lock must be held and selem->local_storage == local_storage.
@@ -432,7 +434,6 @@ void bpf_selem_link_map(struct bpf_local_storage_map *smap, 
	unsigned long flags;



	raw_spin_lock_irqsave(&b->lock, flags);

	RCU_INIT_POINTER(SDATA(selem)->smap, smap);

	hlist_add_head_rcu(&selem->map_node, &b->list);

	raw_spin_unlock_irqrestore(&b->lock, flags);

}
@@ -586,7 +587,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, 


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

		if (err) {

			bpf_selem_free(selem, smap, true);

			bpf_selem_free(selem, true);

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

			return ERR_PTR(err);

		}
@@ -662,7 +663,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, 
	bpf_selem_free_list(&old_selem_free_list, false);

	if (alloc_selem) {

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

		bpf_selem_free(alloc_selem, smap, true);

		bpf_selem_free(alloc_selem, true);

	}

	return err ? ERR_PTR(err) : SDATA(selem);

}

net/core/bpf_sk_storage.c

+1 −1
Original line number Diff line number Diff line
@@ -196,7 +196,7 @@ 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) {

				bpf_selem_free(copy_selem, smap, true);

				bpf_selem_free(copy_selem, true);

				atomic_sub(smap->elem_size,

					   &newsk->sk_omem_alloc);

				bpf_map_put(map);