diff --git a/src/allocator.rs b/src/allocator.rs
index 77c6a0a1..653ba85c 100644
--- a/src/allocator.rs
+++ b/src/allocator.rs
@@ -1,4 +1,5 @@
 use core::alloc::{GlobalAlloc, Layout};
+use core::convert::TryInto;
 use core::ptr;
 
 use crate::bindings;
@@ -10,7 +11,11 @@ unsafe impl GlobalAlloc for KernelAllocator {
     unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
         // krealloc is used instead of kmalloc because kmalloc is an inline function and can't be
         // bound to as a result
-        bindings::krealloc(ptr::null(), layout.size(), bindings::GFP_KERNEL) as *mut u8
+        bindings::krealloc(
+            ptr::null(),
+            layout.size().try_into().unwrap(),
+            bindings::GFP_KERNEL,
+        ) as *mut u8
     }
 
     unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
diff --git a/src/file_operations.rs b/src/file_operations.rs
index 4376873e..d59e5269 100644
--- a/src/file_operations.rs
+++ b/src/file_operations.rs
@@ -46,10 +46,10 @@ unsafe extern "C" fn open_callback<T: FileOperations>(
 unsafe extern "C" fn read_callback<T: Read>(
     file: *mut bindings::file,
     buf: *mut c_types::c_char,
-    len: c_types::c_size_t,
+    len: c_types::c_ulonglong,
     offset: *mut bindings::loff_t,
-) -> c_types::c_ssize_t {
-    let mut data = match UserSlicePtr::new(buf as *mut c_types::c_void, len) {
+) -> c_types::c_longlong {
+    let mut data = match UserSlicePtr::new(buf as *mut c_types::c_void, len.try_into().unwrap()) {
         Ok(ptr) => ptr.writer(),
         Err(e) => return e.to_kernel_errno().try_into().unwrap(),
     };
@@ -62,7 +62,7 @@ unsafe extern "C" fn read_callback<T: Read>(
     };
     match f.read(&mut data, positive_offset) {
         Ok(()) => {
-            let written = len - data.len();
+            let written = len - (data.len() as u64);
             (*offset) += bindings::loff_t::try_from(written).unwrap();
             written.try_into().unwrap()
         }
@@ -73,10 +73,10 @@ unsafe extern "C" fn read_callback<T: Read>(
 unsafe extern "C" fn write_callback<T: Write>(
     file: *mut bindings::file,
     buf: *const c_types::c_char,
-    len: c_types::c_size_t,
+    len: c_types::c_ulonglong,
     offset: *mut bindings::loff_t,
-) -> c_types::c_ssize_t {
-    let mut data = match UserSlicePtr::new(buf as *mut c_types::c_void, len) {
+) -> c_types::c_longlong {
+    let mut data = match UserSlicePtr::new(buf as *mut c_types::c_void, len.try_into().unwrap()) {
         Ok(ptr) => ptr.reader(),
         Err(e) => return e.to_kernel_errno().try_into().unwrap(),
     };
@@ -89,7 +89,7 @@ unsafe extern "C" fn write_callback<T: Write>(
     };
     match f.write(&mut data, positive_offset) {
         Ok(()) => {
-            let read = len - data.len();
+            let read = len - (data.len() as u64);
             (*offset) += bindings::loff_t::try_from(read).unwrap();
             read.try_into().unwrap()
         }
diff --git a/src/sysctl.rs b/src/sysctl.rs
index 71b054a1..a6c7fa20 100644
--- a/src/sysctl.rs
+++ b/src/sysctl.rs
@@ -1,5 +1,6 @@
 use alloc::boxed::Box;
 use alloc::vec;
+use core::convert::TryInto;
 use core::mem;
 use core::ptr;
 use core::sync::atomic;
@@ -83,7 +84,7 @@ unsafe extern "C" fn proc_handler<T: SysctlStorage>(
     ctl: *mut bindings::ctl_table,
     write: c_types::c_int,
     buffer: *mut c_types::c_void,
-    len: *mut usize,
+    len: *mut c_types::c_ulonglong,
     ppos: *mut bindings::loff_t,
 ) -> c_types::c_int {
     // If we're reading from some offset other than the beginning of the file,
@@ -93,7 +94,7 @@ unsafe extern "C" fn proc_handler<T: SysctlStorage>(
         return 0;
     }
 
-    let data = match UserSlicePtr::new(buffer, *len) {
+    let data = match UserSlicePtr::new(buffer, (*len).try_into().unwrap()) {
         Ok(ptr) => ptr,
         Err(e) => return e.to_kernel_errno(),
     };
@@ -108,7 +109,7 @@ unsafe extern "C" fn proc_handler<T: SysctlStorage>(
         let mut writer = data.writer();
         storage.read_value(&mut writer)
     };
-    *len = bytes_processed;
+    *len = bytes_processed.try_into().unwrap();
     *ppos += *len as bindings::loff_t;
     match result {
         Ok(()) => 0,