[dpdk-dev] [PATCH v2] eal/freebsd: lock memory device to prevent conflicts

[Bruce Richardson <bruce.richardson@intel.com>]

Only a single DPDK process on the system can be using the /dev/contigmem
mappings at a time, but this was never explicitly enforced, e.g. when
using --in-memory flag on two processes. To prevent possible conflict
issues, we lock the dev node when it's in use, preventing other DPDK
processes from starting up and causing problems for us.

Fixes: 764bf26873b9 ("add FreeBSD support")
Cc: stable@dpdk.org

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
---

V2: Adding missing LOCK_NB flag to make sure the process doesn't sit
    waiting for the lock to be released

 lib/eal/freebsd/eal_hugepage_info.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/eal/freebsd/eal_hugepage_info.c b/lib/eal/freebsd/eal_hugepage_info.c
index 408f054f7a..9dbe375bd3 100644
--- a/lib/eal/freebsd/eal_hugepage_info.c
+++ b/lib/eal/freebsd/eal_hugepage_info.c
@@ -90,6 +90,10 @@ eal_hugepage_info_init(void)
 		RTE_LOG(ERR, EAL, "could not open "CONTIGMEM_DEV"\n");
 		return -1;
 	}
+	if (flock(fd, LOCK_EX | LOCK_NB) < 0) {
+		RTE_LOG(ERR, EAL, "could not lock memory. Is another DPDK process running?\n");
+		return -1;
+	}

 	if (buffer_size >= 1<<30)
 		RTE_LOG(INFO, EAL, "Contigmem driver has %d buffers, each of size %dGB\n",
--
2.30.2