chore: Fix clippy

Fix as `doc_lazy_continuation`, `manual_c_str_literals` and
`unused_must_use` clippy lints.

Signed-off-by: Ruoqing He <[email protected]>

Author: RuoqingHe

src/ioctls/system.rs

@@ -96,7 +96,7 @@ impl Kvm {
     /// ```
     pub fn open_with_cloexec(close_on_exec: bool) -> Result<RawFd> {
         // SAFETY: Safe because we give a constant nul-terminated string.
-        let kvm_path = unsafe { CStr::from_bytes_with_nul_unchecked(b"/dev/kvm\0") };
+        let kvm_path = c"/dev/kvm";
         Self::open_with_cloexec_at(kvm_path, close_on_exec)
     }
 
@@ -741,7 +741,7 @@ mod tests {
 
     #[test]
     fn test_kvm_new_with_path() {
-        let kvm_path = unsafe { CStr::from_bytes_with_nul_unchecked(b"/dev/kvm\0") };
+        let kvm_path = c"/dev/kvm";
         Kvm::new_with_path(kvm_path).unwrap();
     }
 
@@ -981,6 +981,6 @@ mod tests {
 
         // Don't drop the File object, or it'll notice the file it's trying to close is
         // invalid and abort the process.
-        faulty_kvm.kvm.into_raw_fd();
+        let _ = faulty_kvm.kvm.into_raw_fd();
     }
 }

src/ioctls/vcpu.rs

@@ -1088,7 +1088,6 @@ impl VcpuFd {
         target_arch = "arm",
         target_arch = "aarch64"
     ))]
-
     pub fn set_vcpu_events(&self, vcpu_events: &kvm_vcpu_events) -> Result<()> {
         // SAFETY: Here we trust the kernel not to read past the end of the kvm_vcpu_events struct.
         let ret = unsafe { ioctl_with_ref(self, KVM_SET_VCPU_EVENTS(), vcpu_events) };
@@ -1639,7 +1638,7 @@ impl VcpuFd {
     /// # Arguments
     ///
     /// * `freq` - The frequency unit is KHz as per the KVM API documentation
-    /// for `KVM_SET_TSC_KHZ`.
+    ///   for `KVM_SET_TSC_KHZ`.
     ///
     /// # Example
     ///
@@ -2575,7 +2574,7 @@ mod tests {
 
         // Don't drop the File object, or it'll notice the file it's trying to close is
         // invalid and abort the process.
-        faulty_vcpu_fd.vcpu.into_raw_fd();
+        let _ = faulty_vcpu_fd.vcpu.into_raw_fd();
     }
 
     #[test]
@@ -2699,7 +2698,7 @@ mod tests {
 
         // Don't drop the File object, or it'll notice the file it's trying to close is
         // invalid and abort the process.
-        faulty_vcpu_fd.vcpu.into_raw_fd();
+        let _ = faulty_vcpu_fd.vcpu.into_raw_fd();
     }
 
     #[test]

src/ioctls/vm.rs

@@ -913,8 +913,7 @@ impl VmFd {
         // For ease of access we are saving the bitmap in a u64 vector. We are using ceil to
         // make sure we count all dirty pages even when `memory_size` is not a multiple of
         // `page_size * 64`.
-        let div_ceil = |dividend, divisor| (dividend + divisor - 1) / divisor;
-        let bitmap_size = div_ceil(memory_size, page_size * 64);
+        let bitmap_size = memory_size.div_ceil(page_size * 64);
         let mut bitmap = vec![0u64; bitmap_size];
         let dirtylog = kvm_dirty_log {
             slot,
@@ -2406,7 +2405,7 @@ mod tests {
 
         // Don't drop the File object, or it'll notice the file it's trying to close is
         // invalid and abort the process.
-        faulty_vm_fd.vm.into_raw_fd();
+        let _ = faulty_vm_fd.vm.into_raw_fd();
     }
 
     #[test]