Remove redundant uses of std::mem::zeroed()

We already use "inode: 0". 

See 7c2c7f5874 (Use uninit instead of zeroed, 2025-05-19).

Part of #12337

src/fs.rs

@@ -326,9 +326,19 @@ fn update_metadata(old_file: &File, new_file: &File) {
         // only be updated once every 10 milliseconds.
         #[cfg(any(target_os = "linux", target_os = "android"))]
         {
-            let mut times: [libc::timespec; 2] = unsafe { std::mem::zeroed() };
-            times[0].tv_nsec = libc::UTIME_OMIT; // don't change atime
-            if unsafe { libc::clock_gettime(libc::CLOCK_REALTIME, &mut times[1]) } == 0 {
+            use libc::timespec;
+            let mut time = timespec {
+                tv_sec: 0,
+                tv_nsec: 0,
+            };
+            if unsafe { libc::clock_gettime(libc::CLOCK_REALTIME, &mut time) } == 0 {
+                let times = [
+                    timespec {
+                        tv_sec: 0,
+                        tv_nsec: libc::UTIME_OMIT, // don't change atime,
+                    },
+                    time,
+                ];
                 unsafe {
                     // This accesses both times[0] and times[1]. Check `utimensat(2)` for details.
                     libc::futimens(new_file.as_raw_fd(), &times[0]);

src/topic_monitor.rs

@@ -28,6 +28,7 @@
 use nix::errno::Errno;
 use nix::unistd;
 use std::cell::Cell;
+use std::mem::MaybeUninit;
 use std::os::fd::AsRawFd as _;
 use std::sync::atomic::{AtomicU8, Ordering};
 use std::sync::{Condvar, Mutex, MutexGuard};
@@ -172,14 +173,12 @@ pub fn new() -> BinarySemaphore {
         // On BSD sem_init uses a file descriptor under the hood which doesn't get CLOEXEC (see #7304).
         // So use fast semaphores on Linux only.
         #[cfg(target_os = "linux")]
-        {
-            // sem_t does not have an initializer in Rust so we use zeroed().
-            let sem = Box::pin(UnsafeCell::new(unsafe { std::mem::zeroed() }));
-
-            let res = unsafe { libc::sem_init(sem.get(), 0, 0) };
-            if res == 0 {
-                return Self::Semaphore(sem);
-            }
+        if let Some(sem) = {
+            let mut sem = MaybeUninit::uninit();
+            let res = unsafe { libc::sem_init(sem.as_mut_ptr(), 0, 0) };
+            (res == 0).then_some(unsafe { sem.assume_init() })
+        } {
+            return Self::Semaphore(Box::pin(UnsafeCell::new(sem)));
         }
 
         let pipes = fds::make_autoclose_pipes().expect("Failed to make pubsub pipes");

src/wutil/dir_iter.rs

@@ -83,7 +83,7 @@ pub fn dev_inode(&self) -> Option<DevInode> {
     // Reset our fields.
     fn reset(&mut self) {
         self.name.clear();
-        self.inode = unsafe { std::mem::zeroed() };
+        self.inode = 0;
         self.typ.set(None);
         self.dev_inode.set(None);
     }