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bpf: consolidate bpf_prog_put{, _rcu} dismantle paths

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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 ac00737f4e ("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: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann 2015-10-29 14:58:08 +01:00 committed by David S. Miller
parent c210129760
commit e9d8afa90b
2 changed files with 7 additions and 11 deletions
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3
kernel/bpf/core.c
View File

@ -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);

15
kernel/bpf/syscall.c
View File

@ -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);