Re: [dpdk-dev] [PATCH 1/2] ethdev: make flow API primary/secondary process safe

[Ferruh Yigit]

On 3/15/2021 7:27 PM, Stephen Hemminger wrote:
Posix mutex are not by default safe for protecting for usage
from multiple processes. The flow ops mutex could be used by
both primary and secondary processes.
Bugzilla ID: 662
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
Fixes: 80d1a9aff7f6 ("ethdev: make flow API thread safe")
Cc: suanmi...@nvidia.com
---
  lib/librte_ethdev/rte_ethdev.c | 6 +++++-
  1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 6f514c388b4e..d1024df408a5 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -470,6 +470,7 @@ rte_eth_dev_allocate(const char *name)
  {
        uint16_t port_id;
        struct rte_eth_dev *eth_dev = NULL;
+       pthread_mutexattr_t attr;
        size_t name_len;
  
  	name_len = strnlen(name, RTE_ETH_NAME_MAX_LEN);
@@ -506,7 +507,10 @@ rte_eth_dev_allocate(const char *name)
        strlcpy(eth_dev->data->name, name, sizeof(eth_dev->data->name));
        eth_dev->data->port_id = port_id;
        eth_dev->data->mtu = RTE_ETHER_MTU;
-       pthread_mutex_init(&eth_dev->data->flow_ops_mutex, NULL);
+
+       pthread_mutexattr_init(&attr);
+       pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);        
+       pthread_mutex_init(&eth_dev->data->flow_ops_mutex, &attr);
  
  unlock:
        rte_spinlock_unlock(&eth_dev_shared_data->ownership_lock);


The problem looks legit, and there seems no obvious downside of the patch. Also 
Huawei test result was good, hence:

Acked-by: Ferruh Yigit <ferruh.yi...@intel.com>


And the PMDs that set the 'RTE_ETH_DEV_FLOW_OPS_THREAD_SAFE' flag already not 
affected from this change at all, but how safe mutli process applications will 
be for them is still not clear.