> > Full barriers order the preceding index store against the following load of > the > interrupt mask or pending size and stay seq_cst; read barriers become > acquire fences. Same code generated on x86 and arm64. > > The write barrier before publishing the transmit index becomes a release > fence. Nominally stronger on arm64, but it is immediately followed by a full > barrier cmpset; converting that to a release compare-exchange is left for the > rte_atomic32 removal series. > > Signed-off-by: Stephen Hemminger <[email protected]>
Reviewed-by: Long Li <[email protected]> > --- > drivers/bus/vmbus/vmbus_bufring.c | 6 +++--- > drivers/bus/vmbus/vmbus_channel.c | 6 +++--- > 2 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/bus/vmbus/vmbus_bufring.c > b/drivers/bus/vmbus/vmbus_bufring.c > index f622869974..31478d3bfa 100644 > --- a/drivers/bus/vmbus/vmbus_bufring.c > +++ b/drivers/bus/vmbus/vmbus_bufring.c > @@ -58,11 +58,11 @@ void vmbus_br_setup(struct vmbus_br *br, void *buf, > unsigned int blen) static inline bool vmbus_txbr_need_signal(const struct > vmbus_bufring *vbr, uint32_t old_windex) { > - rte_smp_mb(); > + rte_atomic_thread_fence(rte_memory_order_seq_cst); > if (vbr->imask) > return false; > > - rte_smp_rmb(); > + rte_atomic_thread_fence(rte_memory_order_acquire); > > /* > * This is the only case we need to signal when the @@ -158,7 +158,7 > @@ vmbus_txbr_write(struct vmbus_br *tbr, const struct iovec iov[], int > iovlen, > RTE_ASSERT(windex == next_windex); > > /* Ensure that data is available before updating host index */ > - rte_smp_wmb(); > + rte_atomic_thread_fence(rte_memory_order_release); > > /* Checkin for our reservation. wait for our turn to update host */ > while (!rte_atomic32_cmpset(&vbr->windex, old_windex, > next_windex)) diff --git a/drivers/bus/vmbus/vmbus_channel.c > b/drivers/bus/vmbus/vmbus_channel.c > index 2648d8e3fd..10293f59be 100644 > --- a/drivers/bus/vmbus/vmbus_channel.c > +++ b/drivers/bus/vmbus/vmbus_channel.c > @@ -211,7 +211,7 @@ bool rte_vmbus_chan_rx_empty(const struct > vmbus_channel *channel) { > const struct vmbus_br *br = &channel->rxbr; > > - rte_smp_rmb(); > + rte_atomic_thread_fence(rte_memory_order_acquire); > return br->vbr->rindex == br->vbr->windex; } > > @@ -229,13 +229,13 @@ void rte_vmbus_chan_signal_read(struct > rte_vmbus_device *dev, > return; > > /* Make sure reading of pending happens after new read index */ > - rte_smp_mb(); > + rte_atomic_thread_fence(rte_memory_order_seq_cst); > > pending_sz = rbr->vbr->pending_send; > if (!pending_sz) > return; > > - rte_smp_rmb(); > + rte_atomic_thread_fence(rte_memory_order_acquire); > write_sz = vmbus_br_availwrite(rbr, rbr->vbr->windex); > > /* If there was space before then host was not blocked */ > -- > 2.53.0
