Re: [dpdk-dev] [PATCH 1/2] librte_ethdev: Introduce a function to release HW rings

[Burakov, Anatoly]

On 03-May-20 5:26 PM, Renata Saiakhova wrote:
Free previously allocated memzone for HW rings
Signed-off-by: Renata Saiakhova <renata.saiakh...@ekinops.com>
---
  lib/librte_ethdev/rte_ethdev.c           | 23 +++++++++++++++++++++++
  lib/librte_ethdev/rte_ethdev_driver.h    | 14 ++++++++++++++
  lib/librte_ethdev/rte_ethdev_version.map |  1 +
  3 files changed, 38 insertions(+)

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 72aed59a5..c6d27e1aa 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -4206,6 +4206,29 @@ rte_eth_dma_zone_reserve(const struct rte_eth_dev *dev, 
const char *ring_name,
                        RTE_MEMZONE_IOVA_CONTIG, align);
  }
  
+int
+rte_eth_dma_zone_free(const struct rte_eth_dev *dev, const char *ring_name,
+               uint16_t queue_id)
+{
+       char z_name[RTE_MEMZONE_NAMESIZE];
+       const struct rte_memzone *mz;
+       int rc = 0;
+
+       snprintf(z_name, sizeof(z_name), "eth_p%d_q%d_%s",
+                       dev->data->port_id, queue_id, ring_name);
+       if (rc >= RTE_MEMZONE_NAMESIZE) {
+               RTE_ETHDEV_LOG(ERR, "ring name too long\n");
+               rte_errno = ENAMETOOLONG;
+               return NULL;
+       }
+
+       mz = rte_memzone_lookup(z_name);
+       if (mz)
+               rc = rte_memzone_free(mz);

This is racy. Please just use rte_memzone_free() unconditionally. It'll 
return 0 if memzone existed, or will set rte_errno to EINVAL if it 
didn't. (this is suboptimal, it should be ENOENT, but changing this 
would be an API break... I'll submit a patch for future release to fix this)


--
Thanks,
Anatoly