Commit 8801ccd0500437 introduced a compilation failure with clang
version 10.0.0-4ubuntu1:
../../net/vhost-vdpa.c:654:16: error: variable 'vdpa_device_fd' is
used uninitialized whenever 'if' condition is false
[-Werror,-Wsometimes-uninitialized]
} else if (opts->has_vhostfd) {
^~~~~~~~~~~~~~~~~
../../net/vhost-vdpa.c:662:33: note: uninitialized use occurs here
r = vhost_vdpa_get_features(vdpa_device_fd, &features, errp);
^~~~~~~~~~~~~~
../../net/vhost-vdpa.c:654:12: note: remove the 'if' if its condition
is always true
} else if (opts->has_vhostfd) {
^~~~~~~~~~~~~~~~~~~~~~~
../../net/vhost-vdpa.c:629:23: note: initialize the variable
'vdpa_device_fd' to silence this warning
int vdpa_device_fd;
^
= 0
1 error generated.
It's a false positive -- the compiler doesn't manage to figure out
that the error checks further up mean that there's no code path where
vdpa_device_fd isn't initialized. Put another way, the problem is
that we check "if (opts->has_vhostfd)" when in fact that condition
must always be true. A cleverer static analyser would probably warn
that we were checking an always-true condition.
Fix the compilation failure by removing the unnecessary if().
Fixes: 8801ccd0500437 ("vhost-vdpa: allow passing opened vhostfd to vhost-vdpa")
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
---
Stefan, do you want to apply this directly as a build fix?
---
net/vhost-vdpa.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 854ebd61ae6..e370ecb8ebd 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -651,7 +651,8 @@ int net_init_vhost_vdpa(const Netdev *netdev, const char
*name,
if (vdpa_device_fd == -1) {
return -errno;
}
- } else if (opts->has_vhostfd) {
+ } else {
+ /* has_vhostfd */
vdpa_device_fd = monitor_fd_param(monitor_cur(), opts->vhostfd, errp);
if (vdpa_device_fd == -1) {
error_prepend(errp, "vhost-vdpa: unable to parse vhostfd: ");
--
2.25.1
