misc: Fix clippy issues

Signed-off-by: Bo Chen <chen.bo@intel.com>

qcow/src/qcow.rs

@@ -566,7 +566,7 @@ impl QcowFile {
 
         // Set the refcount for each refcount table cluster.
         let cluster_size = 0x01u64 << qcow.header.cluster_bits;
-        let refcount_table_base = qcow.header.refcount_table_offset as u64;
+        let refcount_table_base = qcow.header.refcount_table_offset;
         let end_cluster_addr =
             refcount_table_base + u64::from(qcow.header.refcount_table_clusters) * cluster_size;
 
@@ -963,7 +963,7 @@ impl QcowFile {
     // Gets the offset of the given guest address in the host file. If L1, L2, or data clusters have
     // yet to be allocated, return None.
     fn file_offset_read(&mut self, address: u64) -> std::io::Result<Option<u64>> {
-        if address >= self.virtual_size() as u64 {
+        if address >= self.virtual_size() {
             return Err(std::io::Error::from_raw_os_error(EINVAL));
         }
 
@@ -1006,7 +1006,7 @@ impl QcowFile {
     // Gets the offset of the given guest address in the host file. If L1, L2, or data clusters need
     // to be allocated, they will be.
     fn file_offset_write(&mut self, address: u64) -> std::io::Result<u64> {
-        if address >= self.virtual_size() as u64 {
+        if address >= self.virtual_size() {
             return Err(std::io::Error::from_raw_os_error(EINVAL));
         }
 
@@ -1123,7 +1123,7 @@ impl QcowFile {
 
     // Returns true if the cluster containing `address` is already allocated.
     fn cluster_allocated(&mut self, address: u64) -> std::io::Result<bool> {
-        if address >= self.virtual_size() as u64 {
+        if address >= self.virtual_size() {
             return Err(std::io::Error::from_raw_os_error(EINVAL));
         }
 
@@ -1195,7 +1195,7 @@ impl QcowFile {
     // Deallocate the storage for the cluster starting at `address`.
     // Any future reads of this cluster will return all zeroes.
     fn deallocate_cluster(&mut self, address: u64) -> std::io::Result<()> {
-        if address >= self.virtual_size() as u64 {
+        if address >= self.virtual_size() {
             return Err(std::io::Error::from_raw_os_error(EINVAL));
         }
 
@@ -1417,7 +1417,7 @@ impl Drop for QcowFile {
 
 impl Read for QcowFile {
     fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
-        let address: u64 = self.current_offset as u64;
+        let address: u64 = self.current_offset;
         let read_count: usize = self.limit_range_file(address, buf.len());
 
         let mut nread: usize = 0;
@@ -1479,7 +1479,7 @@ impl Seek for QcowFile {
 
 impl Write for QcowFile {
     fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
-        let address: u64 = self.current_offset as u64;
+        let address: u64 = self.current_offset;
         let write_count: usize = self.limit_range_file(address, buf.len());
 
         let mut nwritten: usize = 0;