diff --git a/src/io_uring.rs b/src/io_uring.rs
index baf4c934..23b8749d 100644
--- a/src/io_uring.rs
+++ b/src/io_uring.rs
@@ -22,7 +22,6 @@ use {
             copyhashmap::CopyHashMap,
             errorfmt::ErrorFmt,
             mmap::{mmap, Mmapped},
-            numcell::NumCell,
             oserror::OsError,
             ptr_ext::{MutPtrExt, PtrExt},
             stack::Stack,
@@ -254,10 +253,10 @@ struct IoUringData {
 
     cqes_consumed: AsyncEvent,
 
-    next: NumCell<u64>,
-    to_encode: SyncQueue<u64>,
-    pending_in_kernel: CopyHashMap<u64, ()>,
-    tasks: CopyHashMap<u64, Box<dyn Task>>,
+    next: IoUringTaskIds,
+    to_encode: SyncQueue<IoUringTaskId>,
+    pending_in_kernel: CopyHashMap<IoUringTaskId, ()>,
+    tasks: CopyHashMap<IoUringTaskId, Box<dyn Task>>,
 
     pending_results: PendingResults,
 
@@ -276,7 +275,7 @@ struct IoUringData {
 }
 
 unsafe trait Task {
-    fn id(&self) -> u64;
+    fn id(&self) -> IoUringTaskId;
     fn complete(self: Box<Self>, ring: &IoUringData, res: i32);
     fn encode(&self, sqe: &mut io_uring_sqe);
 
@@ -347,8 +346,9 @@ impl IoUringData {
                 let entry = self.cqmap.deref()[idx].get();
                 head = head.wrapping_add(1);
                 self.cqhead.deref().store(head, Release);
-                if let Some(pending) = self.tasks.remove(&entry.user_data) {
-                    self.pending_in_kernel.remove(&entry.user_data);
+                let id = IoUringTaskId(entry.user_data);
+                if let Some(pending) = self.tasks.remove(&id) {
+                    self.pending_in_kernel.remove(&id);
                     pending.complete(self, entry.res);
                 }
             }
@@ -384,7 +384,7 @@ impl IoUringData {
                 let sqe = self.sqesmap.deref()[idx].get().deref_mut();
                 self.sqmap.deref()[idx].set(idx as _);
                 *sqe = Default::default();
-                sqe.user_data = id;
+                sqe.user_data = id.raw();
                 task.encode(sqe);
                 if has_timeout {
                     sqe.flags |= IOSQE_IO_LINK;
@@ -404,11 +404,11 @@ impl IoUringData {
         }
     }
 
-    fn id_raw(&self) -> u64 {
-        self.next.fetch_add(1)
+    fn id_raw(&self) -> IoUringTaskId {
+        self.next.next()
     }
 
-    fn cancel_task(&self, id: u64) {
+    fn cancel_task(&self, id: IoUringTaskId) {
         if !self.tasks.contains(&id) {
             return;
         }
@@ -466,8 +466,17 @@ impl IoUringData {
     }
 }
 
+linear_ids!(IoUringTaskIds, IoUringTaskId, u64);
+
+#[expect(clippy::derivable_impls)]
+impl Default for IoUringTaskId {
+    fn default() -> Self {
+        Self(0)
+    }
+}
+
 struct Cancellable<'a> {
-    id: u64,
+    id: IoUringTaskId,
     data: &'a IoUringData,
 }
 
diff --git a/src/io_uring/ops/accept.rs b/src/io_uring/ops/accept.rs
index 6f751dcf..149592ea 100644
--- a/src/io_uring/ops/accept.rs
+++ b/src/io_uring/ops/accept.rs
@@ -2,7 +2,7 @@ use {
     crate::io_uring::{
         pending_result::PendingResult,
         sys::{io_uring_sqe, IORING_OP_ACCEPT},
-        IoUring, IoUringData, IoUringError, Task, TaskResultExt,
+        IoUring, IoUringData, IoUringError, IoUringTaskId, Task, TaskResultExt,
     },
     std::rc::Rc,
     uapi::{c, OwnedFd},
@@ -39,14 +39,14 @@ struct Data {
 
 #[derive(Default)]
 pub struct AcceptTask {
-    id: u64,
+    id: IoUringTaskId,
     fd: i32,
     flags: u32,
     data: Option<Data>,
 }
 
 unsafe impl Task for AcceptTask {
-    fn id(&self) -> u64 {
+    fn id(&self) -> IoUringTaskId {
         self.id
     }
 
diff --git a/src/io_uring/ops/async_cancel.rs b/src/io_uring/ops/async_cancel.rs
index d322fd3b..3874ab98 100644
--- a/src/io_uring/ops/async_cancel.rs
+++ b/src/io_uring/ops/async_cancel.rs
@@ -2,7 +2,7 @@ use {
     crate::{
         io_uring::{
             sys::{io_uring_sqe, IORING_OP_ASYNC_CANCEL},
-            IoUringData, Task,
+            IoUringData, IoUringTaskId, Task,
         },
         utils::errorfmt::ErrorFmt,
     },
@@ -11,12 +11,12 @@ use {
 
 #[derive(Default)]
 pub struct AsyncCancelTask {
-    id: u64,
-    target: u64,
+    id: IoUringTaskId,
+    target: IoUringTaskId,
 }
 
 impl IoUringData {
-    pub fn cancel_task_in_kernel(&self, target: u64) {
+    pub fn cancel_task_in_kernel(&self, target: IoUringTaskId) {
         let id = self.id_raw();
         let mut task = self.cached_cancels.pop().unwrap_or_default();
         task.id = id;
@@ -26,7 +26,7 @@ impl IoUringData {
 }
 
 unsafe impl Task for AsyncCancelTask {
-    fn id(&self) -> u64 {
+    fn id(&self) -> IoUringTaskId {
         self.id
     }
 
@@ -41,7 +41,7 @@ unsafe impl Task for AsyncCancelTask {
 
     fn encode(&self, sqe: &mut io_uring_sqe) {
         sqe.opcode = IORING_OP_ASYNC_CANCEL;
-        sqe.u2.addr = self.target;
+        sqe.u2.addr = self.target.raw();
     }
 
     fn is_cancel(&self) -> bool {
diff --git a/src/io_uring/ops/connect.rs b/src/io_uring/ops/connect.rs
index 0aca6829..a23d460e 100644
--- a/src/io_uring/ops/connect.rs
+++ b/src/io_uring/ops/connect.rs
@@ -2,7 +2,7 @@ use {
     crate::io_uring::{
         pending_result::PendingResult,
         sys::{io_uring_sqe, IORING_OP_CONNECT},
-        IoUring, IoUringData, IoUringError, Task, TaskResultExt,
+        IoUring, IoUringData, IoUringError, IoUringTaskId, Task, TaskResultExt,
     },
     std::{mem, ptr, rc::Rc},
     uapi::{c, OwnedFd, SockAddr},
@@ -37,7 +37,7 @@ struct Data {
 }
 
 pub struct ConnectTask {
-    id: u64,
+    id: IoUringTaskId,
     fd: i32,
     sockaddr: c::sockaddr_storage,
     addrlen: u64,
@@ -47,7 +47,7 @@ pub struct ConnectTask {
 impl Default for ConnectTask {
     fn default() -> Self {
         Self {
-            id: 0,
+            id: Default::default(),
             fd: 0,
             sockaddr: uapi::pod_zeroed(),
             addrlen: 0,
@@ -57,7 +57,7 @@ impl Default for ConnectTask {
 }
 
 unsafe impl Task for ConnectTask {
-    fn id(&self) -> u64 {
+    fn id(&self) -> IoUringTaskId {
         self.id
     }
 
diff --git a/src/io_uring/ops/poll.rs b/src/io_uring/ops/poll.rs
index 6edab2d4..1ac45281 100644
--- a/src/io_uring/ops/poll.rs
+++ b/src/io_uring/ops/poll.rs
@@ -3,7 +3,7 @@ use {
         ops::TaskResult,
         pending_result::PendingResult,
         sys::{io_uring_sqe, IORING_OP_POLL_ADD},
-        IoUring, IoUringData, IoUringError, Task, TaskResultExt,
+        IoUring, IoUringData, IoUringError, IoUringTaskId, Task, TaskResultExt,
     },
     std::rc::Rc,
     uapi::{c, OwnedFd},
@@ -45,14 +45,14 @@ struct Data {
 
 #[derive(Default)]
 pub struct PollTask {
-    id: u64,
+    id: IoUringTaskId,
     events: u16,
     fd: i32,
     data: Option<Data>,
 }
 
 unsafe impl Task for PollTask {
-    fn id(&self) -> u64 {
+    fn id(&self) -> IoUringTaskId {
         self.id
     }
 
diff --git a/src/io_uring/ops/read_write.rs b/src/io_uring/ops/read_write.rs
index 9ebf2c1d..f8db92cb 100644
--- a/src/io_uring/ops/read_write.rs
+++ b/src/io_uring/ops/read_write.rs
@@ -3,7 +3,7 @@ use {
         io_uring::{
             pending_result::PendingResult,
             sys::{io_uring_sqe, IORING_OP_READ, IORING_OP_WRITE},
-            IoUring, IoUringData, IoUringError, Task, TaskResultExt,
+            IoUring, IoUringData, IoUringError, IoUringTaskId, Task, TaskResultExt,
         },
         time::Time,
         utils::buf::Buf,
@@ -66,7 +66,7 @@ struct ReadWriteTaskData {
 
 #[derive(Default)]
 pub struct ReadWriteTask {
-    id: u64,
+    id: IoUringTaskId,
     has_timeout: bool,
     fd: c::c_int,
     buf: usize,
@@ -76,7 +76,7 @@ pub struct ReadWriteTask {
 }
 
 unsafe impl Task for ReadWriteTask {
-    fn id(&self) -> u64 {
+    fn id(&self) -> IoUringTaskId {
         self.id
     }
 
diff --git a/src/io_uring/ops/recvmsg.rs b/src/io_uring/ops/recvmsg.rs
index 4196f8d4..6bea0d09 100644
--- a/src/io_uring/ops/recvmsg.rs
+++ b/src/io_uring/ops/recvmsg.rs
@@ -3,7 +3,7 @@ use {
         io_uring::{
             pending_result::PendingResult,
             sys::{io_uring_sqe, IORING_OP_RECVMSG},
-            IoUring, IoUringData, IoUringError, Task,
+            IoUring, IoUringData, IoUringError, IoUringTaskId, Task,
         },
         utils::buf::Buf,
     },
@@ -85,7 +85,7 @@ struct Data {
 }
 
 pub struct RecvmsgTask {
-    id: u64,
+    id: IoUringTaskId,
     fd: c::c_int,
     bufs: Vec<Buf>,
     iovecs: Vec<c::iovec>,
@@ -97,7 +97,7 @@ pub struct RecvmsgTask {
 impl Default for RecvmsgTask {
     fn default() -> Self {
         RecvmsgTask {
-            id: 0,
+            id: Default::default(),
             fd: 0,
             bufs: vec![],
             iovecs: vec![],
@@ -109,7 +109,7 @@ impl Default for RecvmsgTask {
 }
 
 unsafe impl Task for RecvmsgTask {
-    fn id(&self) -> u64 {
+    fn id(&self) -> IoUringTaskId {
         self.id
     }
 
diff --git a/src/io_uring/ops/sendmsg.rs b/src/io_uring/ops/sendmsg.rs
index 23cb7a8f..67d7b4e8 100644
--- a/src/io_uring/ops/sendmsg.rs
+++ b/src/io_uring/ops/sendmsg.rs
@@ -3,7 +3,7 @@ use {
         io_uring::{
             pending_result::PendingResult,
             sys::{io_uring_sqe, IORING_OP_SENDMSG},
-            IoUring, IoUringData, IoUringError, Task,
+            IoUring, IoUringData, IoUringError, IoUringTaskId, Task,
         },
         time::Time,
         utils::{buf::Buf, vec_ext::UninitVecExt},
@@ -91,7 +91,7 @@ struct SendmsgTaskData {
 }
 
 pub struct SendmsgTask {
-    id: u64,
+    id: IoUringTaskId,
     iovecs: Vec<c::iovec>,
     msghdr: c::msghdr,
     bufs: Vec<Buf>,
@@ -106,7 +106,7 @@ impl Default for SendmsgTask {
     fn default() -> Self {
         unsafe {
             SendmsgTask {
-                id: 0,
+                id: Default::default(),
                 iovecs: vec![],
                 msghdr: MaybeUninit::zeroed().assume_init(),
                 bufs: vec![],
@@ -121,7 +121,7 @@ impl Default for SendmsgTask {
 }
 
 unsafe impl Task for SendmsgTask {
-    fn id(&self) -> u64 {
+    fn id(&self) -> IoUringTaskId {
         self.id
     }
 
diff --git a/src/io_uring/ops/timeout.rs b/src/io_uring/ops/timeout.rs
index 3567a56f..e8067c61 100644
--- a/src/io_uring/ops/timeout.rs
+++ b/src/io_uring/ops/timeout.rs
@@ -2,7 +2,7 @@ use {
     crate::io_uring::{
         pending_result::PendingResult,
         sys::{io_uring_sqe, IORING_OP_TIMEOUT, IORING_TIMEOUT_ABS},
-        IoUring, IoUringData, IoUringError, Task,
+        IoUring, IoUringData, IoUringError, IoUringTaskId, Task,
     },
     uapi::c,
 };
@@ -16,7 +16,7 @@ pub(super) struct timespec64 {
 
 #[derive(Default)]
 pub struct TimeoutTask {
-    id: u64,
+    id: IoUringTaskId,
     timespec: timespec64,
     pr: Option<PendingResult>,
 }
@@ -42,7 +42,7 @@ impl IoUring {
 }
 
 unsafe impl Task for TimeoutTask {
-    fn id(&self) -> u64 {
+    fn id(&self) -> IoUringTaskId {
         self.id
     }
 
diff --git a/src/io_uring/ops/timeout_link.rs b/src/io_uring/ops/timeout_link.rs
index aabaa421..023fbd99 100644
--- a/src/io_uring/ops/timeout_link.rs
+++ b/src/io_uring/ops/timeout_link.rs
@@ -2,14 +2,14 @@ use crate::{
     io_uring::{
         ops::timeout::timespec64,
         sys::{io_uring_sqe, IORING_OP_LINK_TIMEOUT, IORING_TIMEOUT_ABS},
-        IoUring, IoUringData, Task,
+        IoUring, IoUringData, IoUringTaskId, Task,
     },
     time::Time,
 };
 
 #[derive(Default)]
 pub struct TimeoutLinkTask {
-    id: u64,
+    id: IoUringTaskId,
     timespec: timespec64,
 }
 
@@ -27,7 +27,7 @@ impl IoUring {
 }
 
 unsafe impl Task for TimeoutLinkTask {
-    fn id(&self) -> u64 {
+    fn id(&self) -> IoUringTaskId {
         self.id
     }