Merge tag 'bitmap-for-6.18' of https://github.com/norov/linux

Pull bitmap updates from Yury Norov:

 - FIELD_PREP_WM16() consolidation (Nicolas)

 - bitmaps for Rust (Burak)

 - __fls() fix for arc (Kees)

* tag 'bitmap-for-6.18' of https://github.com/norov/linux: (25 commits)
  rust: add dynamic ID pool abstraction for bitmap
  rust: add find_bit_benchmark_rust module.
  rust: add bitmap API.
  rust: add bindings for bitops.h
  rust: add bindings for bitmap.h
  phy: rockchip-pcie: switch to FIELD_PREP_WM16 macro
  clk: sp7021: switch to FIELD_PREP_WM16 macro
  PCI: dw-rockchip: Switch to FIELD_PREP_WM16 macro
  PCI: rockchip: Switch to FIELD_PREP_WM16* macros
  net: stmmac: dwmac-rk: switch to FIELD_PREP_WM16 macro
  ASoC: rockchip: i2s-tdm: switch to FIELD_PREP_WM16_CONST macro
  drm/rockchip: dw_hdmi: switch to FIELD_PREP_WM16* macros
  phy: rockchip-usb: switch to FIELD_PREP_WM16 macro
  drm/rockchip: inno-hdmi: switch to FIELD_PREP_WM16 macro
  drm/rockchip: dw_hdmi_qp: switch to FIELD_PREP_WM16 macro
  phy: rockchip-samsung-dcphy: switch to FIELD_PREP_WM16 macro
  drm/rockchip: vop2: switch to FIELD_PREP_WM16 macro
  drm/rockchip: dsi: switch to FIELD_PREP_WM16* macros
  phy: rockchip-emmc: switch to FIELD_PREP_WM16 macro
  drm/rockchip: lvds: switch to FIELD_PREP_WM16 macro
  ...

3 files changed, 118 insertions, 0 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index fd14468e1b03..cab4c7b27e54 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2621,6 +2621,19 @@ config FIND_BIT_BENCHMARK
 
 	  If unsure, say N.
 
+config FIND_BIT_BENCHMARK_RUST
+	tristate "Test find_bit functions in Rust"
+	depends on RUST
+	help
+	  This builds the "find_bit_benchmark_rust" module. It is a micro
+          benchmark that measures the performance of Rust functions that
+          correspond to the find_*_bit() operations in C. It follows the
+          FIND_BIT_BENCHMARK closely but will in general not yield same
+          numbers due to extra bounds checks and overhead of foreign
+          function calls.
+
+	  If unsure, say N.
+
 config TEST_FIRMWARE
 	tristate "Test firmware loading via userspace interface"
 	depends on FW_LOADER
diff --git a/lib/Makefile b/lib/Makefile
index 15a03f4c16e2..1ab2c4be3b66 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -62,6 +62,7 @@ obj-y += hexdump.o
 obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o
 obj-y += kstrtox.o
 obj-$(CONFIG_FIND_BIT_BENCHMARK) += find_bit_benchmark.o
+obj-$(CONFIG_FIND_BIT_BENCHMARK_RUST) += find_bit_benchmark_rust.o
 obj-$(CONFIG_TEST_BPF) += test_bpf.o
 test_dhry-objs := dhry_1.o dhry_2.o dhry_run.o
 obj-$(CONFIG_TEST_DHRY) += test_dhry.o
diff --git a/lib/find_bit_benchmark_rust.rs b/lib/find_bit_benchmark_rust.rs
new file mode 100644
index 000000000000..6bdc51de2f30
--- /dev/null
+++ b/lib/find_bit_benchmark_rust.rs
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+//! Benchmark for find_bit-like methods in Bitmap Rust API.
+
+use kernel::alloc::flags::GFP_KERNEL;
+use kernel::bindings;
+use kernel::bitmap::BitmapVec;
+use kernel::error::{code, Result};
+use kernel::prelude::module;
+use kernel::time::{Instant, Monotonic};
+use kernel::ThisModule;
+use kernel::{pr_cont, pr_err};
+
+const BITMAP_LEN: usize = 4096 * 8 * 10;
+// Reciprocal of the fraction of bits that are set in sparse bitmap.
+const SPARSENESS: usize = 500;
+
+/// Test module that benchmarks performance of traversing bitmaps.
+struct Benchmark();
+
+fn test_next_bit(bitmap: &BitmapVec) {
+    let time = Instant::<Monotonic>::now();
+    let mut cnt = 0;
+    let mut i = 0;
+
+    while let Some(index) = bitmap.next_bit(i) {
+        cnt += 1;
+        i = index + 1;
+        // CONFIG_RUST_BITMAP_HARDENED enforces strict bounds.
+        if i == BITMAP_LEN {
+            break;
+        }
+    }
+
+    let delta = time.elapsed();
+    pr_cont!(
+        "\nnext_bit:           {:18} ns, {:6} iterations",
+        delta.as_nanos(),
+        cnt
+    );
+}
+
+fn test_next_zero_bit(bitmap: &BitmapVec) {
+    let time = Instant::<Monotonic>::now();
+    let mut cnt = 0;
+    let mut i = 0;
+
+    while let Some(index) = bitmap.next_zero_bit(i) {
+        cnt += 1;
+        i = index + 1;
+        // CONFIG_RUST_BITMAP_HARDENED enforces strict bounds.
+        if i == BITMAP_LEN {
+            break;
+        }
+    }
+
+    let delta = time.elapsed();
+    pr_cont!(
+        "\nnext_zero_bit:      {:18} ns, {:6} iterations",
+        delta.as_nanos(),
+        cnt
+    );
+}
+
+fn find_bit_test() {
+    pr_err!("Benchmark");
+    pr_cont!("\nStart testing find_bit() Rust with random-filled bitmap");
+
+    let mut bitmap = BitmapVec::new(BITMAP_LEN, GFP_KERNEL).expect("alloc bitmap failed");
+    bitmap.fill_random();
+
+    test_next_bit(&bitmap);
+    test_next_zero_bit(&bitmap);
+
+    pr_cont!("\nStart testing find_bit() Rust with sparse bitmap");
+
+    let mut bitmap = BitmapVec::new(BITMAP_LEN, GFP_KERNEL).expect("alloc sparse bitmap failed");
+    let nbits = BITMAP_LEN / SPARSENESS;
+    for _i in 0..nbits {
+        // SAFETY: __get_random_u32_below is safe to call with any u32 argument.
+        let bit =
+            unsafe { bindings::__get_random_u32_below(BITMAP_LEN.try_into().unwrap()) as usize };
+        bitmap.set_bit(bit);
+    }
+
+    test_next_bit(&bitmap);
+    test_next_zero_bit(&bitmap);
+    pr_cont!("\n");
+}
+
+impl kernel::Module for Benchmark {
+    fn init(_module: &'static ThisModule) -> Result<Self> {
+        find_bit_test();
+        // Return error so test module can be inserted again without rmmod.
+        Err(code::EINVAL)
+    }
+}
+
+module! {
+    type: Benchmark,
+    name: "find_bit_benchmark_rust",
+    authors: ["Burak Emir <bqe@google.com>"],
+    description: "Module with benchmark for bitmap Rust API",
+    license: "GPL v2",
+}