[dpdk-dev] [PATCH 07/11] ethdev: add lock to port allocation check

[Thomas Monjalon]

From: Matan Azrad <ma...@mellanox.com>

When comparing the port name, there can be a race condition with
a thread allocating a new port and writing the name at the same time.
It can lead to match with a partial name by error.

The check of the port is now considered as a critical section
protected with locks.

This fix will be even more required for multi-process when the
port availability will rely only on the name, in a following patch.

Fixes: 84934303a17c ("ethdev: synchronize port allocation")
Cc: sta...@dpdk.org

Signed-off-by: Matan Azrad <ma...@mellanox.com>
Acked-by: Thomas Monjalon <tho...@monjalon.net>
---
 lib/librte_ethdev/rte_ethdev.c | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index ae86d0ba7..357be2dca 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -227,8 +227,8 @@ rte_eth_dev_shared_data_prepare(void)
        rte_spinlock_unlock(&rte_eth_shared_data_lock);
 }
 
-struct rte_eth_dev *
-rte_eth_dev_allocated(const char *name)
+static struct rte_eth_dev *
+rte_eth_dev_allocated_lock_free(const char *name)
 {
        unsigned i;
 
@@ -240,6 +240,22 @@ rte_eth_dev_allocated(const char *name)
        return NULL;
 }
 
+struct rte_eth_dev *
+rte_eth_dev_allocated(const char *name)
+{
+       struct rte_eth_dev *ethdev;
+
+       rte_eth_dev_shared_data_prepare();
+
+       rte_spinlock_lock(&rte_eth_dev_shared_data->ownership_lock);
+
+       ethdev = rte_eth_dev_allocated_lock_free(name);
+
+       rte_spinlock_unlock(&rte_eth_dev_shared_data->ownership_lock);
+
+       return ethdev;
+}
+
 static uint16_t
 rte_eth_dev_find_free_port(void)
 {
@@ -286,7 +302,7 @@ rte_eth_dev_allocate(const char *name)
                goto unlock;
        }
 
-       if (rte_eth_dev_allocated(name) != NULL) {
+       if (rte_eth_dev_allocated_lock_free(name) != NULL) {
                ethdev_log(ERR,
                        "Ethernet Device with name %s already allocated!",
                        name);
-- 
2.16.2