diff options
| author |   Eric Dumazet <edumazet@google.com> | 2023-08-02 13:14:57 +0000 |
|---|---|---|
| committer |   Jakub Kicinski <kuba@kernel.org> | 2023-08-03 10:58:24 -0700 |
| commit | 285ce119a3c6c4502585936650143e54c8692788 (patch) | |
| tree | a51bad7b7b019df43ffd6fc1029481076a14a765 | |
| parent | tcp_metrics: annotate data-races around tm->tcpm_stamp (diff) | |
| download | linux-285ce119a3c6c4502585936650143e54c8692788.tar.xz linux-285ce119a3c6c4502585936650143e54c8692788.zip | |
tcp_metrics: annotate data-races around tm->tcpm_lock
tm->tcpm_lock can be read or written locklessly.
Add needed READ_ONCE()/WRITE_ONCE() to document this.
Fixes: 51c5d0c4b169 ("tcp: Maintain dynamic metrics in local cache.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230802131500.1478140-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ipv4/tcp_metrics.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 838616588796..131fa3004969 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -59,7 +59,8 @@ static inline struct net *tm_net(struct tcp_metrics_block *tm) static bool tcp_metric_locked(struct tcp_metrics_block *tm, enum tcp_metric_index idx) { - return tm->tcpm_lock & (1 << idx); + /* Paired with WRITE_ONCE() in tcpm_suck_dst() */ + return READ_ONCE(tm->tcpm_lock) & (1 << idx); } static u32 tcp_metric_get(struct tcp_metrics_block *tm, @@ -110,7 +111,8 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm, val |= 1 << TCP_METRIC_CWND; if (dst_metric_locked(dst, RTAX_REORDERING)) val |= 1 << TCP_METRIC_REORDERING; - tm->tcpm_lock = val; + /* Paired with READ_ONCE() in tcp_metric_locked() */ + WRITE_ONCE(tm->tcpm_lock, val); msval = dst_metric_raw(dst, RTAX_RTT); tm->tcpm_vals[TCP_METRIC_RTT] = msval * USEC_PER_MSEC; |