Commit 85192dbf authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Daniel Borkmann

bpf: Convert bpf_prog refcnt to atomic64_t

Similarly to bpf_map's refcnt/usercnt, convert bpf_prog's refcnt to atomic64
and remove artificial 32k limit. This allows to make bpf_prog's refcounting
non-failing, simplifying logic of users of bpf_prog_add/bpf_prog_inc.

Validated compilation by running allyesconfig kernel build.
Suggested-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191117172806.2195367-3-andriin@fb.com
parent 1e0bd5a0
......@@ -3171,13 +3171,8 @@ static int bnxt_init_one_rx_ring(struct bnxt *bp, int ring_nr)
bnxt_init_rxbd_pages(ring, type);
if (BNXT_RX_PAGE_MODE(bp) && bp->xdp_prog) {
rxr->xdp_prog = bpf_prog_add(bp->xdp_prog, 1);
if (IS_ERR(rxr->xdp_prog)) {
int rc = PTR_ERR(rxr->xdp_prog);
rxr->xdp_prog = NULL;
return rc;
}
bpf_prog_add(bp->xdp_prog, 1);
rxr->xdp_prog = bp->xdp_prog;
}
prod = rxr->rx_prod;
for (i = 0; i < bp->rx_ring_size; i++) {
......
......@@ -1876,13 +1876,8 @@ static int nicvf_xdp_setup(struct nicvf *nic, struct bpf_prog *prog)
if (nic->xdp_prog) {
/* Attach BPF program */
nic->xdp_prog = bpf_prog_add(nic->xdp_prog, nic->rx_queues - 1);
if (!IS_ERR(nic->xdp_prog)) {
bpf_attached = true;
} else {
ret = PTR_ERR(nic->xdp_prog);
nic->xdp_prog = NULL;
}
bpf_prog_add(nic->xdp_prog, nic->rx_queues - 1);
bpf_attached = true;
}
/* Calculate Tx queues needed for XDP and network stack */
......
......@@ -1807,11 +1807,8 @@ static int setup_xdp(struct net_device *dev, struct bpf_prog *prog)
if (prog && !xdp_mtu_valid(priv, dev->mtu))
return -EINVAL;
if (prog) {
prog = bpf_prog_add(prog, priv->num_channels);
if (IS_ERR(prog))
return PTR_ERR(prog);
}
if (prog)
bpf_prog_add(prog, priv->num_channels);
up = netif_running(dev);
need_update = (!!priv->xdp_prog != !!prog);
......
......@@ -2286,11 +2286,7 @@ int mlx4_en_try_alloc_resources(struct mlx4_en_priv *priv,
lockdep_is_held(&priv->mdev->state_lock));
if (xdp_prog && carry_xdp_prog) {
xdp_prog = bpf_prog_add(xdp_prog, tmp->rx_ring_num);
if (IS_ERR(xdp_prog)) {
mlx4_en_free_resources(tmp);
return PTR_ERR(xdp_prog);
}
bpf_prog_add(xdp_prog, tmp->rx_ring_num);
for (i = 0; i < tmp->rx_ring_num; i++)
rcu_assign_pointer(tmp->rx_ring[i]->xdp_prog,
xdp_prog);
......@@ -2782,11 +2778,9 @@ static int mlx4_xdp_set(struct net_device *dev, struct bpf_prog *prog)
* program for a new one.
*/
if (priv->tx_ring_num[TX_XDP] == xdp_ring_num) {
if (prog) {
prog = bpf_prog_add(prog, priv->rx_ring_num - 1);
if (IS_ERR(prog))
return PTR_ERR(prog);
}
if (prog)
bpf_prog_add(prog, priv->rx_ring_num - 1);
mutex_lock(&mdev->state_lock);
for (i = 0; i < priv->rx_ring_num; i++) {
old_prog = rcu_dereference_protected(
......@@ -2807,13 +2801,8 @@ static int mlx4_xdp_set(struct net_device *dev, struct bpf_prog *prog)
if (!tmp)
return -ENOMEM;
if (prog) {
prog = bpf_prog_add(prog, priv->rx_ring_num - 1);
if (IS_ERR(prog)) {
err = PTR_ERR(prog);
goto out;
}
}
if (prog)
bpf_prog_add(prog, priv->rx_ring_num - 1);
mutex_lock(&mdev->state_lock);
memcpy(&new_prof, priv->prof, sizeof(struct mlx4_en_port_profile));
......@@ -2862,7 +2851,6 @@ static int mlx4_xdp_set(struct net_device *dev, struct bpf_prog *prog)
unlock_out:
mutex_unlock(&mdev->state_lock);
out:
kfree(tmp);
return err;
}
......
......@@ -408,12 +408,9 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c,
rq->stats = &c->priv->channel_stats[c->ix].rq;
INIT_WORK(&rq->recover_work, mlx5e_rq_err_cqe_work);
rq->xdp_prog = params->xdp_prog ? bpf_prog_inc(params->xdp_prog) : NULL;
if (IS_ERR(rq->xdp_prog)) {
err = PTR_ERR(rq->xdp_prog);
rq->xdp_prog = NULL;
goto err_rq_wq_destroy;
}
if (params->xdp_prog)
bpf_prog_inc(params->xdp_prog);
rq->xdp_prog = params->xdp_prog;
rq_xdp_ix = rq->ix;
if (xsk)
......@@ -4406,16 +4403,11 @@ static int mlx5e_xdp_set(struct net_device *netdev, struct bpf_prog *prog)
/* no need for full reset when exchanging programs */
reset = (!priv->channels.params.xdp_prog || !prog);
if (was_opened && !reset) {
if (was_opened && !reset)
/* num_channels is invariant here, so we can take the
* batched reference right upfront.
*/
prog = bpf_prog_add(prog, priv->channels.num);
if (IS_ERR(prog)) {
err = PTR_ERR(prog);
goto unlock;
}
}
bpf_prog_add(prog, priv->channels.num);
if (was_opened && reset) {
struct mlx5e_channels new_channels = {};
......
......@@ -2107,12 +2107,8 @@ static int qede_start_queues(struct qede_dev *edev, bool clear_stats)
if (rc)
goto out;
fp->rxq->xdp_prog = bpf_prog_add(edev->xdp_prog, 1);
if (IS_ERR(fp->rxq->xdp_prog)) {
rc = PTR_ERR(fp->rxq->xdp_prog);
fp->rxq->xdp_prog = NULL;
goto out;
}
bpf_prog_add(edev->xdp_prog, 1);
fp->rxq->xdp_prog = edev->xdp_prog;
}
if (fp->type & QEDE_FASTPATH_TX) {
......
......@@ -2445,11 +2445,8 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
if (!prog && !old_prog)
return 0;
if (prog) {
prog = bpf_prog_add(prog, vi->max_queue_pairs - 1);
if (IS_ERR(prog))
return PTR_ERR(prog);
}
if (prog)
bpf_prog_add(prog, vi->max_queue_pairs - 1);
/* Make sure NAPI is not using any XDP TX queues for RX. */
if (netif_running(dev)) {
......
......@@ -485,7 +485,7 @@ struct bpf_func_info_aux {
};
struct bpf_prog_aux {
atomic_t refcnt;
atomic64_t refcnt;
u32 used_map_cnt;
u32 max_ctx_offset;
u32 max_pkt_offset;
......@@ -770,9 +770,9 @@ extern const struct bpf_verifier_ops xdp_analyzer_ops;
struct bpf_prog *bpf_prog_get(u32 ufd);
struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
bool attach_drv);
struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog, int i);
void bpf_prog_add(struct bpf_prog *prog, int i);
void bpf_prog_sub(struct bpf_prog *prog, int i);
struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog);
void bpf_prog_inc(struct bpf_prog *prog);
struct bpf_prog * __must_check bpf_prog_inc_not_zero(struct bpf_prog *prog);
void bpf_prog_put(struct bpf_prog *prog);
int __bpf_prog_charge(struct user_struct *user, u32 pages);
......@@ -912,10 +912,8 @@ static inline struct bpf_prog *bpf_prog_get_type_dev(u32 ufd,
return ERR_PTR(-EOPNOTSUPP);
}
static inline struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog,
int i)
static inline void bpf_prog_add(struct bpf_prog *prog, int i)
{
return ERR_PTR(-EOPNOTSUPP);
}
static inline void bpf_prog_sub(struct bpf_prog *prog, int i)
......@@ -926,9 +924,8 @@ static inline void bpf_prog_put(struct bpf_prog *prog)
{
}
static inline struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog)
static inline void bpf_prog_inc(struct bpf_prog *prog)
{
return ERR_PTR(-EOPNOTSUPP);
}
static inline struct bpf_prog *__must_check
......
......@@ -31,7 +31,7 @@ static void *bpf_any_get(void *raw, enum bpf_type type)
{
switch (type) {
case BPF_TYPE_PROG:
raw = bpf_prog_inc(raw);
bpf_prog_inc(raw);
break;
case BPF_TYPE_MAP:
bpf_map_inc_with_uref(raw);
......@@ -534,7 +534,8 @@ static struct bpf_prog *__get_prog_inode(struct inode *inode, enum bpf_prog_type
if (!bpf_prog_get_ok(prog, &type, false))
return ERR_PTR(-EINVAL);
return bpf_prog_inc(prog);
bpf_prog_inc(prog);
return prog;
}
struct bpf_prog *bpf_prog_get_type_path(const char *name, enum bpf_prog_type type)
......
......@@ -1339,7 +1339,7 @@ static void __bpf_prog_put_noref(struct bpf_prog *prog, bool deferred)
static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock)
{
if (atomic_dec_and_test(&prog->aux->refcnt)) {
if (atomic64_dec_and_test(&prog->aux->refcnt)) {
perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_UNLOAD, 0);
/* bpf_prog_free_id() must be called first */
bpf_prog_free_id(prog, do_idr_lock);
......@@ -1445,16 +1445,9 @@ static struct bpf_prog *____bpf_prog_get(struct fd f)
return f.file->private_data;
}
/* prog's refcnt limit */
#define BPF_MAX_REFCNT 32768
struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i)
void bpf_prog_add(struct bpf_prog *prog, int i)
{
if (atomic_add_return(i, &prog->aux->refcnt) > BPF_MAX_REFCNT) {
atomic_sub(i, &prog->aux->refcnt);
return ERR_PTR(-EBUSY);
}
return prog;
atomic64_add(i, &prog->aux->refcnt);
}
EXPORT_SYMBOL_GPL(bpf_prog_add);
......@@ -1465,13 +1458,13 @@ void bpf_prog_sub(struct bpf_prog *prog, int i)
* path holds a reference to the program, thus atomic_sub() can
* be safely used in such cases!
*/
WARN_ON(atomic_sub_return(i, &prog->aux->refcnt) == 0);
WARN_ON(atomic64_sub_return(i, &prog->aux->refcnt) == 0);
}
EXPORT_SYMBOL_GPL(bpf_prog_sub);
struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
void bpf_prog_inc(struct bpf_prog *prog)
{
return bpf_prog_add(prog, 1);
atomic64_inc(&prog->aux->refcnt);
}
EXPORT_SYMBOL_GPL(bpf_prog_inc);
......@@ -1480,12 +1473,7 @@ struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog)
{
int refold;
refold = atomic_fetch_add_unless(&prog->aux->refcnt, 1, 0);
if (refold >= BPF_MAX_REFCNT) {
__bpf_prog_put(prog, false);
return ERR_PTR(-EBUSY);
}
refold = atomic64_fetch_add_unless(&prog->aux->refcnt, 1, 0);
if (!refold)
return ERR_PTR(-ENOENT);
......@@ -1523,7 +1511,7 @@ static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type,
goto out;
}
prog = bpf_prog_inc(prog);
bpf_prog_inc(prog);
out:
fdput(f);
return prog;
......@@ -1714,7 +1702,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
prog->orig_prog = NULL;
prog->jited = 0;
atomic_set(&prog->aux->refcnt, 1);
atomic64_set(&prog->aux->refcnt, 1);
prog->gpl_compatible = is_gpl ? 1 : 0;
if (bpf_prog_is_dev_bound(prog->aux)) {
......
......@@ -10477,12 +10477,9 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
context = parent_event->overflow_handler_context;
#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
if (overflow_handler == bpf_overflow_handler) {
struct bpf_prog *prog = bpf_prog_inc(parent_event->prog);
struct bpf_prog *prog = parent_event->prog;
if (IS_ERR(prog)) {
err = PTR_ERR(prog);
goto err_ns;
}
bpf_prog_inc(prog);
event->prog = prog;
event->orig_overflow_handler =
parent_event->orig_overflow_handler;
......
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