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Commit e9d8afa9 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

bpf: consolidate bpf_prog_put{, _rcu} dismantle paths 



We currently have duplicated cleanup code in bpf_prog_put() and
bpf_prog_put_rcu() cleanup paths. Back then we decided that it was
not worth it to make it a common helper called by both, but with
the recent addition of resource charging, we could have avoided
the fix in commit ac00737f ("bpf: Need to call bpf_prog_uncharge_memlock
from bpf_prog_put") if we would have had only a single, common path.
We can simplify it further by assigning aux->prog only once during
allocation time.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c2101297

kernel/bpf/core.c

+2 −1
Original line number Diff line number Diff line
@@ -92,6 +92,7 @@ struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 


	fp->pages = size / PAGE_SIZE;

	fp->aux = aux;

	fp->aux->prog = fp;



	return fp;

}
@@ -116,6 +117,7 @@ struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 


		memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);

		fp->pages = size / PAGE_SIZE;

		fp->aux->prog = fp;



		/* We keep fp->aux from fp_old around in the new

		 * reallocated structure.
@@ -726,7 +728,6 @@ void bpf_prog_free(struct bpf_prog *fp) 
	struct bpf_prog_aux *aux = fp->aux;



	INIT_WORK(&aux->work, bpf_prog_free_deferred);

	aux->prog = fp;

	schedule_work(&aux->work);

}

EXPORT_SYMBOL_GPL(bpf_prog_free);

kernel/bpf/syscall.c

+5 −10
Original line number Diff line number Diff line
@@ -513,7 +513,7 @@ static void bpf_prog_uncharge_memlock(struct bpf_prog *prog) 
	free_uid(user);

}



static void __prog_put_rcu(struct rcu_head *rcu)

static void __prog_put_common(struct rcu_head *rcu)

{

	struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu);
@@ -525,19 +525,14 @@ static void __prog_put_rcu(struct rcu_head *rcu) 
/* version of bpf_prog_put() that is called after a grace period */

void bpf_prog_put_rcu(struct bpf_prog *prog)

{

	if (atomic_dec_and_test(&prog->aux->refcnt)) {

		prog->aux->prog = prog;

		call_rcu(&prog->aux->rcu, __prog_put_rcu);

	}

	if (atomic_dec_and_test(&prog->aux->refcnt))

		call_rcu(&prog->aux->rcu, __prog_put_common);

}



void bpf_prog_put(struct bpf_prog *prog)

{

	if (atomic_dec_and_test(&prog->aux->refcnt)) {

		free_used_maps(prog->aux);

		bpf_prog_uncharge_memlock(prog);

		bpf_prog_free(prog);

	}

	if (atomic_dec_and_test(&prog->aux->refcnt))

		__prog_put_common(&prog->aux->rcu);

}

EXPORT_SYMBOL_GPL(bpf_prog_put);