Use feature for io-uring instead of cfg

.github/workflows/ci.yml

@@ -120,8 +120,8 @@ jobs:
       - name: test tokio full
         run: |
           set -euxo pipefail
-          cargo nextest run --features full
-          cargo test --doc --features full
+          cargo nextest run --features full,test-util
+          cargo test --doc --features full,test-util
         working-directory: tokio
 
   test-workspace-all-features:
@@ -287,9 +287,10 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: windows-latest
-          - os: ubuntu-latest
-          - os: macos-latest
+          - { os: windows-latest, features: "full,test-util" }
+          - { os: ubuntu-latest, features: "full,test-util" }
+          - { os: ubuntu-latest, features: "full,test-util,io-uring" }
+          - { os: macos-latest, features: "full,test-util" }
     steps:
       - uses: actions/checkout@v5
       - name: Install Rust ${{ env.rust_stable }}
@@ -307,8 +308,8 @@ jobs:
       - name: test tokio full --cfg unstable
         run: |
           set -euxo pipefail
-          cargo nextest run --all-features
-          cargo test --doc --all-features
+          cargo nextest run --features ${{ matrix.features }}
+          cargo test --doc --features ${{ matrix.features }}
         working-directory: tokio
         env:
           RUSTFLAGS: --cfg tokio_unstable -Dwarnings
@@ -350,50 +351,6 @@ jobs:
           # the unstable cfg to RustDoc
           RUSTDOCFLAGS: --cfg tokio_unstable --cfg tokio_taskdump
 
-  test-uring:
-    name: test tokio full --cfg tokio_uring
-    needs: basics
-    runs-on: ${{ matrix.os }}
-    strategy:
-      matrix:
-        include:
-          - os: ubuntu-latest
-    steps:
-      - name: check if io-uring is supported in the CI environment
-        run: |
-          # Try to read the io-uring setting in the kernel config file.
-          # https://github.com/torvalds/linux/blob/75f5f23f8787c5e184fcb2fbcd02d8e9317dc5e7/init/Kconfig#L1782-L1789
-          CONFIG_FILE="/boot/config-$(uname -r)"
-          echo "Checking $CONFIG_FILE for io-uring support"
-          if ! grep -q "CONFIG_IO_URING=y" "$CONFIG_FILE"; then
-            echo "Error: io_uring is not supported"
-            exit 1
-          fi
-
-      - uses: actions/checkout@v5
-      - name: Install Rust ${{ env.rust_stable }}
-        uses: dtolnay/rust-toolchain@stable
-        with:
-            toolchain: ${{ env.rust_stable }}
-
-      - name: Install cargo-nextest
-        uses: taiki-e/install-action@v2
-        with:
-          tool: cargo-nextest
-
-      - uses: Swatinem/rust-cache@v2
-      - name: test tokio full --cfg tokio_uring
-        run: |
-          set -euxo pipefail
-          cargo nextest run --all-features
-          cargo test --doc --all-features
-        working-directory: tokio
-        env:
-          RUSTFLAGS: --cfg tokio_uring -Dwarnings
-          # in order to run doctests for unstable features, we must also pass
-          # the unstable cfg to RustDoc
-          RUSTDOCFLAGS: --cfg tokio_uring
-
   check-unstable-mt-counters:
     name: check tokio full --internal-mt-counters
     needs: basics
@@ -552,7 +509,8 @@ jobs:
           target: ${{ matrix.target }}
 
       - uses: Swatinem/rust-cache@v2
-      - run: cargo check --workspace --all-features --target ${{ matrix.target }}
+      # Don't use --all-features since io-uring will be enabled and is not supported on those targets.
+      - run: cargo check --workspace --features full,test-util --target ${{ matrix.target }}
         env:
           RUSTFLAGS: --cfg tokio_unstable -Dwarnings
 
@@ -622,8 +580,8 @@ jobs:
       - name: Tests run with all features (including parking_lot)
         run: |
           set -euxo pipefail
-          cargo nextest run -p tokio --all-features --target ${{ matrix.target }}
-          cargo test --doc -p tokio --all-features --target ${{ matrix.target }}
+          cargo nextest run -p tokio --features full,test-util --target ${{ matrix.target }}
+          cargo test --doc -p tokio --features full,test-util --target ${{ matrix.target }}
         env:
           RUST_TEST_THREADS: 1
           RUSTFLAGS: --cfg tokio_unstable -Dwarnings --cfg tokio_no_tuning_tests ${{ matrix.rustflags }}
@@ -704,8 +662,8 @@ jobs:
       - uses: Swatinem/rust-cache@v2
       - name: test tokio --all-features
         run: |
-          cargo nextest run -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --all-features
-          cargo test --doc -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --all-features
+          cargo nextest run -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --features full,test-util
+          cargo test --doc -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --features full,test-util
         env:
           RUST_TEST_THREADS: 1
           RUSTFLAGS: --cfg tokio_unstable --cfg tokio_taskdump -Dwarnings --cfg tokio_no_tuning_tests
@@ -731,7 +689,7 @@ jobs:
       # https://github.com/tokio-rs/tokio/pull/5356
       # https://github.com/tokio-rs/tokio/issues/5373
       - name: Check
-        run: cargo hack check -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --feature-powerset --depth 2 --keep-going
+        run: cargo hack check -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --feature-powerset --skip io-uring --depth 2 --keep-going
         env:
           RUSTFLAGS: --cfg tokio_unstable --cfg tokio_taskdump -Dwarnings
 
@@ -743,12 +701,9 @@ jobs:
       matrix:
         include:
           - { name: "", rustflags: "" }
-          # Try with unstable feature flags
           - { name: "--unstable", rustflags: "--cfg tokio_unstable -Dwarnings" }
-          # Try with unstable and taskdump feature flags
           - { name: "--unstable --taskdump", rustflags: "--cfg tokio_unstable -Dwarnings --cfg tokio_taskdump" }
-          - { name: "--tokio_uring", rustflags: "-Dwarnings --cfg tokio_uring" }
-          - { name: "--unstable --taskdump --tokio_uring", rustflags: "--cfg tokio_unstable -Dwarnings --cfg tokio_taskdump --cfg tokio_uring" }
+          - { name: "--unstable --taskdump --io-uring", rustflags: "--cfg tokio_unstable -Dwarnings --cfg tokio_taskdump" }
     steps:
       - uses: actions/checkout@v5
       - name: Install Rust ${{ env.rust_nightly }}
@@ -811,7 +766,7 @@ jobs:
           cargo hack check --all-features --ignore-private
       - name: "check --all-features --unstable -Z minimal-versions"
         env:
-          RUSTFLAGS: --cfg tokio_unstable --cfg tokio_taskdump --cfg tokio_uring -Dwarnings
+          RUSTFLAGS: --cfg tokio_unstable --cfg tokio_taskdump -Dwarnings
         run: |
           # Remove dev-dependencies from Cargo.toml to prevent the next `cargo update`
           # from determining minimal versions based on dev-dependencies.
@@ -847,7 +802,7 @@ jobs:
       matrix:
         rustflags:
           - ""
-          - "--cfg tokio_unstable --cfg tokio_taskdump --cfg tokio_uring -Dwarnings"
+          - "--cfg tokio_unstable --cfg tokio_taskdump -Dwarnings"
     steps:
       - uses: actions/checkout@v5
       - name: Install Rust ${{ env.rust_clippy }}
@@ -869,8 +824,8 @@ jobs:
         run:
           - os: windows-latest
           - os: ubuntu-latest
-            RUSTFLAGS: --cfg tokio_taskdump --cfg tokio_uring
-            RUSTDOCFLAGS: --cfg tokio_taskdump --cfg tokio_uring
+            RUSTFLAGS: --cfg tokio_taskdump
+            RUSTDOCFLAGS: --cfg tokio_taskdump
 
     steps:
       - uses: actions/checkout@v5

.github/workflows/uring-kernel-version-test.yml

@@ -44,8 +44,8 @@ jobs:
         run: |
           # Build both integration (tokio/tests/) and unit (e.g., tokio/src/fs/file/tests.rs) tests with io_uring enabled
           rustup target add x86_64-unknown-linux-musl
-          RUSTFLAGS="--cfg tokio_uring" \
-            cargo test -p tokio --features full \
+          RUSTFLAGS="--cfg tokio_unstable" \
+            cargo test -p tokio --features full,io-uring \
             --target x86_64-unknown-linux-musl --test 'fs*' --lib --no-run
 
       - name: Prepare initramfs + tests binaries

Cargo.toml

@@ -29,6 +29,5 @@ unexpected_cfgs = { level = "warn", check-cfg = [
   'cfg(tokio_no_tuning_tests)',
   'cfg(tokio_taskdump)',
   'cfg(tokio_unstable)',
-  'cfg(tokio_uring)',
   'cfg(target_os, values("cygwin"))',
 ] }

tokio/Cargo.toml

@@ -84,6 +84,8 @@ signal = [
 sync = []
 test-util = ["rt", "sync", "time"]
 time = []
+# Unstable feature. Requires `--cfg tokio_unstable` to enable.
+io-uring = ["dep:io-uring", "libc", "mio/os-poll", "mio/os-ext", "slab"]
 
 [dependencies]
 tokio-macros = { version = "~2.5.0", path = "../tokio-macros", optional = true }
@@ -103,11 +105,13 @@ socket2 = { version = "0.6.0", optional = true, features = ["all"] }
 [target.'cfg(tokio_unstable)'.dependencies]
 tracing = { version = "0.1.29", default-features = false, features = ["std"], optional = true } # Not in full
 
-[target.'cfg(all(tokio_uring, target_os = "linux"))'.dependencies]
-io-uring = { version = "0.7.6", default-features = false }
-libc = { version = "0.2.168" }
-mio = { version = "1.0.1", default-features = false, features = ["os-poll", "os-ext"] }
-slab = "0.4.9"
+# Currently unstable. The API exposed by these features may be broken at any time.
+# Requires `--cfg tokio_unstable` to enable.
+[target.'cfg(all(tokio_unstable, target_os = "linux"))'.dependencies]
+io-uring = { version = "0.7.6", default-features = false, optional = true }
+libc = { version = "0.2.168", optional = true }
+mio = { version = "1.0.1", default-features = false, features = ["os-poll", "os-ext"], optional = true }
+slab = { version = "0.4.9", optional = true }
 
 # Currently unstable. The API exposed by these features may be broken at any time.
 # Requires `--cfg tokio_unstable` to enable.
@@ -165,10 +169,10 @@ tracing-mock = "= 0.1.0-beta.1"
 [package.metadata.docs.rs]
 all-features = true
 # enable unstable features in the documentation
-rustdoc-args = ["--cfg", "docsrs", "--cfg", "tokio_unstable", "--cfg", "tokio_taskdump", "--cfg", "tokio_uring"]
+rustdoc-args = ["--cfg", "docsrs", "--cfg", "tokio_unstable", "--cfg", "tokio_taskdump"]
 # it's necessary to _also_ pass `--cfg tokio_unstable` and `--cfg tokio_taskdump`
 # to rustc, or else dependencies will not be enabled, and the docs build will fail.
-rustc-args = ["--cfg", "tokio_unstable", "--cfg", "tokio_taskdump", "--cfg", "tokio_uring"]
+rustc-args = ["--cfg", "tokio_unstable", "--cfg", "tokio_taskdump"]
 
 [package.metadata.playground]
 features = ["full", "test-util"]

tokio/src/fs/mod.rs

@@ -237,7 +237,7 @@ pub use self::metadata::metadata;
 
 mod open_options;
 pub use self::open_options::OpenOptions;
-cfg_tokio_uring! {
+cfg_io_uring! {
     pub(crate) use self::open_options::UringOpenOptions;
 }