make the code compile when using uclibc

src/sys/uio.rs

@@ -50,16 +50,19 @@ pub fn pwritev<Fd: AsFd, Off: Into<off_t>>(
     iov: &[IoSlice<'_>],
     offset: Off,
 ) -> Result<usize> {
+    let offset = offset.into();
+    // uclibc uses 64-bit offsets for pwritev even if it otherwise uses
+    // 32-bit file offsets.
     #[cfg(target_env = "uclibc")]
-    let offset = offset as libc::off64_t; // uclibc doesn't use off_t
+    let offset = offset as libc::off64_t;
 
     // SAFETY: same as in writev()
     let res = unsafe {
         largefile_fn![pwritev](
             fd.as_fd().as_raw_fd(),
             iov.as_ptr() as *const libc::iovec,
             iov.len() as c_int,
-            offset.into(),
+            offset,
         )
     };
 
@@ -80,16 +83,19 @@ pub fn preadv<Fd: AsFd, Off: Into<off_t>>(
     iov: &mut [IoSliceMut<'_>],
     offset: Off,
 ) -> Result<usize> {
+    let offset = offset.into();
+    // uclibc uses 64-bit offsets for preadv even if it otherwise uses
+    // 32-bit file offsets.
     #[cfg(target_env = "uclibc")]
-    let offset = offset as libc::off64_t; // uclibc doesn't use off_t
+    let offset = offset as libc::off64_t;
 
     // SAFETY: same as in readv()
     let res = unsafe {
         largefile_fn![preadv](
             fd.as_fd().as_raw_fd(),
             iov.as_ptr() as *const libc::iovec,
             iov.len() as c_int,
-            offset.into(),
+            offset,
         )
     };