vhost: fix mem path check

Commit aec8283d47 fixes the compilation issue, but it leads to
one runtime issue: early exit wrongly. In some case, 'path' is NULL, but
'resolved_path' has effective path, it should continue going ahead rather
than exit.
This is due to that qemu unlink the file after it maps the huge page file.
In this special case, it is ok to check the resolved path
when path is NULL if errno indicates "No such file or directory".

Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com>
Acked-by: Huawei Xie <huawei.xie@intel.com>

diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c
index 50cab24ce8d1b8a85e0603b0b1ee294d01588a97..6d8de09430575f92a6dd635eb549914c3653936c 100644 (file)
--- a/lib/librte_vhost/virtio-net.c
+++ b/lib/librte_vhost/virtio-net.c
@@ -247,7 +247,7 @@ host_memory_map(struct virtio_net *dev, struct virtio_memory *mem,
                snprintf(memfile, PATH_MAX, "/proc/%u/fd/%s",
                                pid, dptr->d_name);
                path = realpath(memfile, resolved_path);
-               if (path == NULL) {
+               if ((path == NULL) && (strlen(resolved_path) == 0)) {
                        RTE_LOG(ERR, VHOST_CONFIG,
                                "(%"PRIu64") Failed to resolve fd directory\n",
                                dev->device_fh);