On 07/14/2017 09:30 PM, Stephen Hemminger wrote:
Many drivers are all doing copy/paste of the same code to atomicly
update the link status. Reduce duplication, and allow for future
changes by having common function for this.
Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
---
lib/librte_ether/rte_ethdev.c | 36 ++++++++++++++++++++++++++++++++++++
lib/librte_ether/rte_ethdev.h | 28 ++++++++++++++++++++++++++++
2 files changed, 64 insertions(+)
diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index a1b744704f3a..7532fc6b65f0 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -1332,6 +1332,42 @@ rte_eth_link_get_nowait(uint8_t port_id, struct
rte_eth_link *eth_link)
}
int
+_rte_eth_link_update(struct rte_eth_dev *dev,
+ const struct rte_eth_link *link)
+{
+ volatile struct rte_eth_link *dev_link = &(dev->data->dev_link);
+ struct rte_eth_link old;
+
+ RTE_BUILD_BUG_ON(sizeof(*link) != sizeof(uint64_t));
+
+ old = *dev_link;
+
+ /* Only reason we use cmpset rather than set is
+ * that on some architecture may use sign bit as a flag value.
May I ask to provide more details here.
+ */
+ while (rte_atomic64_cmpset((volatile uint64_t *)dev_link,
+ *(volatile uint64_t *)dev_link,
+ *(const uint64_t *)link) == 0)
Shouldn't it be:
do {
old = *dev_link;
} while (rte_atomic64_cmpset((volatile uint64_t *)dev_link,
*(uint64_t *)&old, *(const uint64_t *)link) == 0);
At least it has some sense to guarantee transition from old to new
talking below comparison into account.
+ continue;
+
+ return (old.link_status == link->link_status) ? -1 : 0;
+}
+
+void _rte_eth_link_read(struct rte_eth_dev *dev,
+ struct rte_eth_link *link)
+{
+ const uint64_t *src = (const uint64_t *)&(dev->data->dev_link);
+ volatile uint64_t *dst = (uint64_t *)link;
+
+ RTE_BUILD_BUG_ON(sizeof(*link) != sizeof(uint64_t));
+
+ /* Note: this should never fail since both destination and expected
+ * values are the same and are a pointer from caller.
+ */
+ rte_atomic64_cmpset(dst, *dst, *src);
+}
+
+int
rte_eth_stats_get(uint8_t port_id, struct rte_eth_stats *stats)
{
struct rte_eth_dev *dev;
diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
index f6837278521c..974657933f23 100644
--- a/lib/librte_ether/rte_ethdev.h
+++ b/lib/librte_ether/rte_ethdev.h
@@ -2219,6 +2219,34 @@ void rte_eth_link_get(uint8_t port_id, struct
rte_eth_link *link);
*/
void rte_eth_link_get_nowait(uint8_t port_id, struct rte_eth_link *link);
+
+/**
+ * @internal
+ * Atomically write the link status for the specific device.
+ * It is for use by DPDK device driver use only.
+ * User applications should not call it
+ *
+ * @param dev
+ * Pointer to struct rte_eth_dev.
+ * @param link
+ * New link status value.
+ * @return
+ * -1 if link state has changed, 0 if the same.
+ */
+int _rte_eth_link_update(struct rte_eth_dev *dev,
+ const struct rte_eth_link *link);
+
+/**
+ * @internal
+ * Atomically read the link speed and status.
+ * @param dev
+ * Pointer to struct rte_eth_dev.
+ * @param link
+ * link status value.
+ */
+void _rte_eth_link_read(struct rte_eth_dev *dev,
+ struct rte_eth_link *link);
+
/**
* Retrieve the general I/O statistics of an Ethernet device.
*
