From: Pavan Nikhilesh <redacted>

The `rte_eth_dma_zone_reserve()` is generally used to create HW rings.
In some scenarios when a driver needs to reconfigure the ring size
since the named memzone already exists it returns the previous memzone
without checking if a different sized ring is requested.

Introduce a check to see if the ring size requested is different from the
previously created memzone length.

Fixes: 719dbebceb81 ("xen: allow determining DOM0 at runtime")
Cc: stable@dpdk.org

Signed-off-by: Pavan Nikhilesh <redacted>
---
 lib/librte_ethdev/rte_ethdev.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 12b66b68c..4ae12e43b 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c

@@ -3604,9 +3604,12 @@ rte_eth_dma_zone_reserve(const struct rte_eth_dev *dev, const char *ring_name,
 	}
 
 	mz = rte_memzone_lookup(z_name);
-	if (mz)
+	if (mz && (mz->len == size))
 		return mz;
 
+	if (mz)
+		rte_memzone_free(mz);
+
 	return rte_memzone_reserve_aligned(z_name, size, socket_id,
 			RTE_MEMZONE_IOVA_CONTIG, align);
 }

-- 
2.21.0