[dpdk-dev] [PATCH v3] vhost: make iotlb cache name unique among multi processes

[Itsuro Oda <oda@valinux.co.jp>]

Currently, iotlb cache name is comprised of vid and virtqueue
index. For example, "iotlb_cache_0_0". Because vid is assigned
per process, iotlb cache name is not unique among multi processes.
For example a secondary process uses a vhost
(ex. eth_vhost0,iface=/tmp/sock0) and another secondary process
uses a vhost (ex. eth_vhost1,iface=/tmp/sock1), iotlb cache
name of both vhost ("iotlb_cache_0_0") are same and as a result
iotlb cache is broken.

This patch makes iotlb cache name unique among milti processes
by adding process id to the iotlb cache name.

The prefix of the name is shortend to "iotlb_" since the maximum
length of pool name is 25 bytes (RTE_MEMPOOL_NAMESIZE is 26).
Note that it is just 25 characters in maximum at the moment.
Here,
* pid_t == int: max 10 digits.
* vid < MAX_VHOST_DECICE(1024): max 4 digits.
* vq_index < VHOST_MAX_VRING(256): max 3 digits.

Fixes: d012d1f293f4 (vhost: add IOTLB helper functions)
Cc: stable@dpdk.org

Signed-off-by: Itsuro Oda <oda@valinux.co.jp>
---
v3:
* change format.
* fix commit message.

v2:
* use the process id to make the iotlb cache name unique.

 lib/librte_vhost/iotlb.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/librte_vhost/iotlb.c b/lib/librte_vhost/iotlb.c
index bc1758528..5b3a0c090 100644
--- a/lib/librte_vhost/iotlb.c
+++ b/lib/librte_vhost/iotlb.c
@@ -308,8 +308,9 @@ vhost_user_iotlb_init(struct virtio_net *dev, int vq_index)
 	TAILQ_INIT(&vq->iotlb_list);
 	TAILQ_INIT(&vq->iotlb_pending_list);
 
-	snprintf(pool_name, sizeof(pool_name), "iotlb_cache_%d_%d",
-			dev->vid, vq_index);
+	snprintf(pool_name, sizeof(pool_name), "iotlb_%u_%d_%d",
+			getpid(), dev->vid, vq_index);
+	VHOST_LOG_CONFIG(DEBUG, "IOTLB cache name: %s\n", pool_name);
 
 	/* If already created, free it and recreate */
 	vq->iotlb_pool = rte_mempool_lookup(pool_name);
-- 
2.17.0