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From: Huawei Xie <huawei.xie@intel.com>
To: dev@dpdk.org
Cc: stephen@networkplumber.org, konstantin.ananyev@intel.com,
thomas.monjalon@6wind.com, Huawei Xie <huawei.xie@intel.com>
Date: Wed, 25 May 2016 00:16:41 +0800
Message-Id: <1464106601-981-1-git-send-email-huawei.xie@intel.com>
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Subject: [dpdk-dev] [PATCH] virtio: use volatile to get used->idx in the loop
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There is no external function call or any barrier in the loop,
the used->idx would only be retrieved once.
Signed-off-by: Huawei Xie <huawei.xie@intel.com>
---
drivers/net/virtio/virtio_ethdev.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index c3fb628..f6d6305 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -204,7 +204,8 @@ virtio_send_command(struct virtqueue *vq, struct virtio_pmd_ctrl *ctrl,
usleep(100);
}
- while (vq->vq_used_cons_idx != vq->vq_ring.used->idx) {
+ while (vq->vq_used_cons_idx !=
+ *((volatile uint16_t *)(&vq->vq_ring.used->idx))) {
uint32_t idx, desc_idx, used_idx;
struct vring_used_elem *uep;
--
1.8.1.4