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| author | Yanqin Wei <Yanqin.Wei@arm.com> | 2019-11-26 15:35:23 +0800 |
|---|---|---|
| committer | Ben Pfaff <blp@ovn.org> | 2019-12-02 14:48:14 -0800 |
| commit | 3343f8d6cfbe358e7f28cbd24b750b01e64f5ddd (patch) | |
| tree | a75585a28a7c312ea7bdab322cf2781516017aaa /lib/netdev-provider.h | |
| parent | e515e66a1900feffd4af08c2596fb8d59b07ddd6 (diff) | |
| download | openvswitch-3343f8d6cfbe358e7f28cbd24b750b01e64f5ddd.tar.gz | |
netdev: use acquire-release semantics for change_seq in netdev
"rxq_enabled" of netdev is writen in the vhost thread and read by pmd
thread once it observes 'change_seq' is updated. This patch is to keep
order on aarch64 or other weak memory model CPU to ensure 'rxq_enabled' is
observed before 'change_seq'.
Reviewed-by: Gavin Hu <Gavin.Hu@arm.com>
Signed-off-by: Yanqin Wei <Yanqin.Wei@arm.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
Diffstat (limited to 'lib/netdev-provider.h')
| -rw-r--r-- | lib/netdev-provider.h | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/lib/netdev-provider.h b/lib/netdev-provider.h index 1e5a40c89..f109c4e66 100644 --- a/lib/netdev-provider.h +++ b/lib/netdev-provider.h @@ -63,7 +63,7 @@ struct netdev { * * Minimally, the sequence number is required to change whenever * 'netdev''s flags, features, ethernet address, or carrier changes. */ - uint64_t change_seq; + atomic_uint64_t change_seq; /* A netdev provider might be unable to change some of the device's * parameter (n_rxq, mtu) when the device is in use. In this case @@ -91,12 +91,17 @@ struct netdev { static inline void netdev_change_seq_changed(const struct netdev *netdev_) { + uint64_t change_seq; struct netdev *netdev = CONST_CAST(struct netdev *, netdev_); seq_change(connectivity_seq_get()); - netdev->change_seq++; - if (!netdev->change_seq) { - netdev->change_seq++; + + atomic_read_relaxed(&netdev->change_seq, &change_seq); + change_seq++; + if (OVS_UNLIKELY(!change_seq)) { + change_seq++; } + atomic_store_explicit(&netdev->change_seq, change_seq, + memory_order_release); } static inline void |