Make the "unstable" feature have no effect (#162)

Dependent crates that rely on "unstable" functionality need to restrict
the set of supported io-uring versions to a predetermined closed range
(e.g. >=0.5.6, <=0.5.8), just in case a future release breaks
compatibility. This makes io-uring version incompatibilities in a
dependency graph more likely, and can complicate packaging for
distributions (see [1] for an example).

Let's rely on the fact that we're pre-1.0 to safely try out new APIs
instead. Still, keep an unused "unstable" feature on the io-uring crate
to avoid breaking compatibility.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=2124697#c76

Signed-off-by: Alberto Faria <afaria@redhat.com>

Signed-off-by: Alberto Faria <afaria@redhat.com>

.github/workflows/rust.yml

@@ -25,7 +25,7 @@ jobs:
         with:
           command: test
           use-cross: true
-          args: --features unstable --target ${{ matrix.target }}
+          args: --target ${{ matrix.target }}
       - uses: actions-rs/cargo@v1
         with:
           command: run
@@ -80,7 +80,7 @@ jobs:
       - uses: actions-rs/clippy-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
-          args: --target ${{ matrix.target }} --features unstable
+          args: --target ${{ matrix.target }}
 
 
   fmt:

Cargo.toml

@@ -34,6 +34,3 @@ bindgen = { version = "0.61", optional = true }
 anyhow = "1"
 socket2 = "0.4"
 slab = "0.4"
-
-[package.metadata.docs.rs]
-features = [ "unstable" ]

io-uring-bench/Cargo.toml

@@ -6,10 +6,6 @@ edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
-[features]
-default = [ "unstable" ]
-unstable = [ "io-uring/unstable" ]
-
 [dependencies]
 io-uring = { path = ".." }
 iou = "0.3"

io-uring-bench/src/iai_new_nop.rs

@@ -26,7 +26,6 @@ fn bench_io_uring() {
     }
 }
 
-#[cfg(feature = "unstable")]
 fn bench_io_uring_batch() {
     use io_uring::{opcode, IoUring};
     use std::mem;
@@ -188,19 +187,10 @@ fn bench_uring_sys_batch() {
     }
 }
 
-#[cfg(feature = "unstable")]
 iai::main!(
     bench_io_uring,
     bench_io_uring_batch,
     bench_iou,
     bench_uring_sys,
     bench_uring_sys_batch
 );
-
-#[cfg(not(feature = "unstable"))]
-iai::main!(
-    bench_io_uring,
-    bench_iou,
-    bench_uring_sys,
-    bench_uring_sys_batch
-);

io-uring-test/Cargo.toml

@@ -15,7 +15,5 @@ once_cell = "1"
 socket2 = "0.4"
 
 [features]
-default = [ "unstable" ]
-unstable = [ "io-uring/unstable" ]
 direct-syscall = [ "io-uring/direct-syscall" ]
 ci = []

io-uring-test/src/main.rs

@@ -14,7 +14,7 @@ fn main() -> anyhow::Result<()> {
 
     test::<squeue::Entry, cqueue::Entry>(IoUring::new(entries)?)?;
 
-    #[cfg(all(feature = "unstable", not(feature = "ci")))]
+    #[cfg(not(feature = "ci"))]
     {
         match IoUring::<squeue::Entry128, cqueue::Entry>::generic_new(entries) {
             Ok(r) => test(r)?,
@@ -70,13 +70,10 @@ fn test<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     tests::queue::test_queue_split(&mut ring, &test)?;
     tests::queue::test_debug_print(&mut ring, &test)?;
 
-    #[cfg(feature = "unstable")]
     tests::queue::test_batch(&mut ring, &test)?;
 
     // register
-    #[cfg(feature = "unstable")]
     tests::register::test_register_files_sparse(&mut ring, &test)?;
-    #[cfg(feature = "unstable")]
     tests::register_buf_ring::test_register_buf_ring(&mut ring, &test)?;
 
     // fs
@@ -93,7 +90,6 @@ fn test<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     tests::fs::test_file_direct_write_read(&mut ring, &test)?;
     #[cfg(not(feature = "ci"))]
     tests::fs::test_statx(&mut ring, &test)?;
-    #[cfg(feature = "unstable")]
     tests::fs::test_file_splice(&mut ring, &test)?;
 
     // timeout
@@ -102,19 +98,16 @@ fn test<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     tests::timeout::test_timeout_remove(&mut ring, &test)?;
     tests::timeout::test_timeout_cancel(&mut ring, &test)?;
     tests::timeout::test_timeout_abs(&mut ring, &test)?;
-    #[cfg(feature = "unstable")]
     tests::timeout::test_timeout_submit_args(&mut ring, &test)?;
 
     // net
     tests::net::test_tcp_write_read(&mut ring, &test)?;
     tests::net::test_tcp_writev_readv(&mut ring, &test)?;
     tests::net::test_tcp_send_recv(&mut ring, &test)?;
-    #[cfg(feature = "unstable")]
     tests::net::test_tcp_zero_copy_send_recv(&mut ring, &test)?;
     tests::net::test_tcp_sendmsg_recvmsg(&mut ring, &test)?;
     tests::net::test_tcp_accept(&mut ring, &test)?;
     tests::net::test_tcp_connect(&mut ring, &test)?;
-    #[cfg(feature = "unstable")]
     tests::net::test_tcp_buffer_select(&mut ring, &test)?;
 
     // queue

io-uring-test/src/tests/fs.rs

@@ -508,7 +508,6 @@ pub fn test_file_direct_write_read<S: squeue::EntryMarker, C: cqueue::EntryMarke
     Ok(())
 }
 
-#[cfg(feature = "unstable")]
 pub fn test_file_splice<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     ring: &mut IoUring<S, C>,
     test: &Test,

io-uring-test/src/tests/mod.rs

@@ -3,6 +3,5 @@ pub mod net;
 pub mod poll;
 pub mod queue;
 pub mod register;
-#[cfg(feature = "unstable")]
 pub mod register_buf_ring;
 pub mod timeout;

io-uring-test/src/tests/net.rs

@@ -113,7 +113,6 @@ pub fn test_tcp_send_recv<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     Ok(())
 }
 
-#[cfg(feature = "unstable")]
 pub fn test_tcp_zero_copy_send_recv<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     ring: &mut IoUring<S, C>,
     test: &Test,
@@ -351,7 +350,6 @@ pub fn test_tcp_connect<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     Ok(())
 }
 
-#[cfg(feature = "unstable")]
 pub fn test_tcp_buffer_select<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     ring: &mut IoUring<S, C>,
     test: &Test,

io-uring-test/src/tests/queue.rs

@@ -29,7 +29,6 @@ pub fn test_nop<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     Ok(())
 }
 
-#[cfg(feature = "unstable")]
 pub fn test_batch<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     ring: &mut IoUring<S, C>,
     test: &Test,

io-uring-test/src/tests/register.rs

@@ -1,9 +1,6 @@
-#[cfg(feature = "unstable")]
 use crate::Test;
-#[cfg(feature = "unstable")]
 use io_uring::{cqueue, opcode, squeue, IoUring};
 
-#[cfg(feature = "unstable")]
 pub fn test_register_files_sparse<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     ring: &mut IoUring<S, C>,
     test: &Test,

io-uring-test/src/tests/timeout.rs

@@ -277,7 +277,6 @@ pub fn test_timeout_abs<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     Ok(())
 }
 
-#[cfg(feature = "unstable")]
 pub fn test_timeout_submit_args<S: squeue::EntryMarker, C: cqueue::EntryMarker>(
     ring: &mut IoUring<S, C>,
     test: &Test,

src/cqueue.rs

@@ -2,7 +2,6 @@
 
 use std::fmt::{self, Debug};
 use std::mem;
-#[cfg(feature = "unstable")]
 use std::mem::MaybeUninit;
 use std::sync::atomic;
 
@@ -49,15 +48,13 @@ pub trait EntryMarker: Clone + Debug + Into<Entry> + Sealed {}
 pub struct Entry(pub(crate) sys::io_uring_cqe);
 
 /// A 32-byte completion queue entry (CQE), representing a complete I/O operation.
-#[cfg(feature = "unstable")]
 #[repr(C)]
 #[derive(Clone)]
 pub struct Entry32(pub(crate) Entry, pub(crate) [u64; 2]);
 
 #[test]
 fn test_entry_sizes() {
     assert_eq!(mem::size_of::<Entry>(), 16);
-    #[cfg(feature = "unstable")]
     assert_eq!(mem::size_of::<Entry32>(), 32);
 }
 
@@ -120,9 +117,6 @@ impl<E: EntryMarker> CompletionQueue<'_, E> {
     /// Whether eventfd notifications are disabled when a request is completed and queued to the CQ
     /// ring. This library currently does not provide a way to set it, so this will always be
     /// `false`.
-    ///
-    /// Requires the `unstable` feature.
-    #[cfg(feature = "unstable")]
     pub fn eventfd_disabled(&self) -> bool {
         unsafe {
             (*self.queue.flags).load(atomic::Ordering::Acquire) & sys::IORING_CQ_EVENTFD_DISABLED
@@ -150,7 +144,6 @@ impl<E: EntryMarker> CompletionQueue<'_, E> {
         self.len() == self.capacity()
     }
 
-    #[cfg(feature = "unstable")]
     #[inline]
     pub fn fill<'a>(&mut self, entries: &'a mut [MaybeUninit<E>]) -> &'a mut [E] {
         let len = std::cmp::min(self.len(), entries.len());
@@ -254,7 +247,6 @@ impl Debug for Entry {
     }
 }
 
-#[cfg(feature = "unstable")]
 impl Entry32 {
     /// The operation-specific result code. For example, for a [`Read`](crate::opcode::Read)
     /// operation this is equivalent to the return value of the `read(2)` system call.
@@ -287,22 +279,18 @@ impl Entry32 {
     }
 }
 
-#[cfg(feature = "unstable")]
 impl Sealed for Entry32 {
     const ADDITIONAL_FLAGS: u32 = sys::IORING_SETUP_CQE32;
 }
 
-#[cfg(feature = "unstable")]
 impl EntryMarker for Entry32 {}
 
-#[cfg(feature = "unstable")]
 impl From<Entry32> for Entry {
     fn from(entry32: Entry32) -> Self {
         entry32.0
     }
 }
 
-#[cfg(feature = "unstable")]
 impl Debug for Entry32 {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("Entry32")
@@ -314,7 +302,6 @@ impl Debug for Entry32 {
     }
 }
 
-#[cfg(feature = "unstable")]
 pub fn buffer_select(flags: u32) -> Option<u16> {
     if flags & sys::IORING_CQE_F_BUFFER != 0 {
         let id = flags >> sys::IORING_CQE_BUFFER_SHIFT;
@@ -328,7 +315,6 @@ pub fn buffer_select(flags: u32) -> Option<u16> {
     }
 }
 
-#[cfg(feature = "unstable")]
 pub fn more(flags: u32) -> bool {
     flags & sys::IORING_CQE_F_MORE != 0
 }

src/lib.rs

@@ -101,7 +101,6 @@ impl<S: squeue::EntryMarker, C: cqueue::EntryMarker> IoUring<S, C> {
     ///
     /// Unlike [`IoUring::new`], this function is available for any combination of submission queue
     /// entry (SQE) and completion queue entry (CQE) types.
-    #[cfg(feature = "unstable")]
     pub fn generic_new(entries: u32) -> io::Result<Self> {
         Self::generic_builder().build(entries)
     }
@@ -113,7 +112,6 @@ impl<S: squeue::EntryMarker, C: cqueue::EntryMarker> IoUring<S, C> {
     /// Unlike [`IoUring::builder`], this function is available for any combination of submission
     /// queue entry (SQE) and completion queue entry (CQE) types.
     #[must_use]
-    #[cfg(feature = "unstable")]
     pub fn generic_builder() -> Builder<S, C> {
         Builder {
             dontfork: false,
@@ -356,15 +354,11 @@ impl<S: squeue::EntryMarker, C: cqueue::EntryMarker> Builder<S, C> {
     /// events. You are only able to [register restrictions](Submitter::register_restrictions) when
     /// the rings are disabled due to concurrency issues. You can enable the rings with
     /// [`Submitter::register_enable_rings`].
-    ///
-    /// Requires the `unstable` feature.
-    #[cfg(feature = "unstable")]
     pub fn setup_r_disabled(&mut self) -> &mut Self {
         self.params.flags |= sys::IORING_SETUP_R_DISABLED;
         self
     }
 
-    #[cfg(feature = "unstable")]
     pub fn setup_coop_taskrun(&mut self) -> &mut Self {
         self.params.flags |= sys::IORING_SETUP_COOP_TASKRUN;
         self
@@ -447,9 +441,6 @@ impl Parameters {
     /// See [the commit message that introduced
     /// it](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d7718a9d25a61442da8ee8aeeff6a0097f0ccfd6)
     /// for more details.
-    ///
-    /// Requires the `unstable` feature.
-    #[cfg(feature = "unstable")]
     pub fn is_feature_fast_poll(&self) -> bool {
         self.0.features & sys::IORING_FEAT_FAST_POLL != 0
     }
@@ -460,17 +451,14 @@ impl Parameters {
         self.0.features & sys::IORING_FEAT_POLL_32BITS != 0
     }
 
-    #[cfg(feature = "unstable")]
     pub fn is_feature_sqpoll_nonfixed(&self) -> bool {
         self.0.features & sys::IORING_FEAT_SQPOLL_NONFIXED != 0
     }
 
-    #[cfg(feature = "unstable")]
     pub fn is_feature_ext_arg(&self) -> bool {
         self.0.features & sys::IORING_FEAT_EXT_ARG != 0
     }
 
-    #[cfg(feature = "unstable")]
     pub fn is_feature_native_workers(&self) -> bool {
         self.0.features & sys::IORING_FEAT_NATIVE_WORKERS != 0
     }