The existing u64_stats_t-based psp counters had two preexisting api usage bugs: u64_stats_init() was never called on the syncp object, and the writer side of the u64_stats_update_begin()/end() api was not serialized. Switch the counters to atomic64_t instead. Atomics need no initialization and are inherently safe against concurrent writers, eliminating both bugs at once. Use atomic64_t rather than atomic_long_t so byte counters don't wrap at 4 GiB on 32-bit builds. Fixes: 178f0763c5f3 ("netdevsim: implement psp device stats") Assisted-by: Codex:gpt-5.5 Signed-off-by: Daniel Zahka --- drivers/net/netdevsim/netdevsim.h | 10 ++++------ drivers/net/netdevsim/psp.c | 24 ++++++++---------------- 2 files changed, 12 insertions(+), 22 deletions(-) diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h index d909c4160ea1..4c9cc96dcec3 100644 --- a/drivers/net/netdevsim/netdevsim.h +++ b/drivers/net/netdevsim/netdevsim.h @@ -22,7 +22,6 @@ #include #include #include -#include #include #include #include @@ -115,11 +114,10 @@ struct netdevsim { int rq_reset_mode; struct { - u64_stats_t rx_packets; - u64_stats_t rx_bytes; - u64_stats_t tx_packets; - u64_stats_t tx_bytes; - struct u64_stats_sync syncp; + atomic64_t rx_packets; + atomic64_t rx_bytes; + atomic64_t tx_packets; + atomic64_t tx_bytes; struct psp_dev __rcu *dev; struct dentry *rereg; struct mutex rereg_lock; diff --git a/drivers/net/netdevsim/psp.c b/drivers/net/netdevsim/psp.c index afe58b21041a..1c415b3d6f1a 100644 --- a/drivers/net/netdevsim/psp.c +++ b/drivers/net/netdevsim/psp.c @@ -50,10 +50,8 @@ nsim_do_psp(struct sk_buff *skb, struct netdevsim *ns, } psp_len = skb->len - skb_inner_transport_offset(skb); - u64_stats_update_begin(&ns->psp.syncp); - u64_stats_inc(&ns->psp.tx_packets); - u64_stats_add(&ns->psp.tx_bytes, psp_len); - u64_stats_update_end(&ns->psp.syncp); + atomic64_inc(&ns->psp.tx_packets); + atomic64_add(psp_len, &ns->psp.tx_bytes); /* Now pretend we just received this frame */ peer_psd = rcu_dereference(peer_ns->psp.dev); @@ -79,10 +77,8 @@ nsim_do_psp(struct sk_buff *skb, struct netdevsim *ns, refcount_inc(&(*psp_ext)->refcnt); skb->decrypted = 1; - u64_stats_update_begin(&peer_ns->psp.syncp); - u64_stats_inc(&peer_ns->psp.rx_packets); - u64_stats_add(&peer_ns->psp.rx_bytes, psp_len); - u64_stats_update_end(&peer_ns->psp.syncp); + atomic64_inc(&peer_ns->psp.rx_packets); + atomic64_add(psp_len, &peer_ns->psp.rx_bytes); } else { struct ipv6hdr *ip6h __maybe_unused; struct iphdr *iph; @@ -180,20 +176,16 @@ static void nsim_assoc_del(struct psp_dev *psd, struct psp_assoc *pas) static void nsim_get_stats(struct psp_dev *psd, struct psp_dev_stats *stats) { struct netdevsim *ns = psd->drv_priv; - unsigned int start; /* WARNING: do *not* blindly zero stats in real drivers! * All required stats must be reported by the device! */ memset(stats, 0, sizeof(struct psp_dev_stats)); - do { - start = u64_stats_fetch_begin(&ns->psp.syncp); - stats->rx_bytes = u64_stats_read(&ns->psp.rx_bytes); - stats->rx_packets = u64_stats_read(&ns->psp.rx_packets); - stats->tx_bytes = u64_stats_read(&ns->psp.tx_bytes); - stats->tx_packets = u64_stats_read(&ns->psp.tx_packets); - } while (u64_stats_fetch_retry(&ns->psp.syncp, start)); + stats->rx_bytes = atomic64_read(&ns->psp.rx_bytes); + stats->rx_packets = atomic64_read(&ns->psp.rx_packets); + stats->tx_bytes = atomic64_read(&ns->psp.tx_bytes); + stats->tx_packets = atomic64_read(&ns->psp.tx_packets); } static struct psp_dev_ops nsim_psp_ops = { -- 2.52.0