scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 172 insertions, 0 deletions

diff --git a/rust/macros/kunit.rs b/rust/macros/kunit.rs
new file mode 100644
index 000000000..ae20ed676
--- /dev/null
+++ b/rust/macros/kunit.rs
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Procedural macro to run KUnit tests using a user-space like syntax.
+//!
+//! Copyright (c) 2023 José Expósito <jose.exposito89@gmail.com>
+
+use std::ffi::CString;
+
+use proc_macro2::TokenStream;
+use quote::{
+    format_ident,
+    quote,
+    ToTokens, //
+};
+use syn::{
+    parse_quote,
+    Error,
+    Ident,
+    Item,
+    ItemMod,
+    LitCStr,
+    Result, //
+};
+
+pub(crate) fn kunit_tests(test_suite: Ident, mut module: ItemMod) -> Result<TokenStream> {
+    if test_suite.to_string().len() > 255 {
+        return Err(Error::new_spanned(
+            test_suite,
+            "test suite names cannot exceed the maximum length of 255 bytes",
+        ));
+    }
+
+    // We cannot handle modules that defer to another file (e.g. `mod foo;`).
+    let Some((module_brace, module_items)) = module.content.take() else {
+        Err(Error::new_spanned(
+            module,
+            "`#[kunit_tests(test_name)]` attribute should only be applied to inline modules",
+        ))?
+    };
+
+    // Make the entire module gated behind `CONFIG_KUNIT`.
+    module
+        .attrs
+        .insert(0, parse_quote!(#[cfg(CONFIG_KUNIT="y")]));
+
+    let mut processed_items = Vec::new();
+    let mut test_cases = Vec::new();
+
+    // Generate the test KUnit test suite and a test case for each `#[test]`.
+    //
+    // The code generated for the following test module:
+    //
+    // ```
+    // #[kunit_tests(kunit_test_suit_name)]
+    // mod tests {
+    //     #[test]
+    //     fn foo() {
+    //         assert_eq!(1, 1);
+    //     }
+    //
+    //     #[test]
+    //     fn bar() {
+    //         assert_eq!(2, 2);
+    //     }
+    // }
+    // ```
+    //
+    // Looks like:
+    //
+    // ```
+    // unsafe extern "C" fn kunit_rust_wrapper_foo(_test: *mut ::kernel::bindings::kunit) { foo(); }
+    // unsafe extern "C" fn kunit_rust_wrapper_bar(_test: *mut ::kernel::bindings::kunit) { bar(); }
+    //
+    // static mut TEST_CASES: [::kernel::bindings::kunit_case; 3] = [
+    //     ::kernel::kunit::kunit_case(c"foo", kunit_rust_wrapper_foo),
+    //     ::kernel::kunit::kunit_case(c"bar", kunit_rust_wrapper_bar),
+    //     ::pin_init::zeroed(),
+    // ];
+    //
+    // ::kernel::kunit_unsafe_test_suite!(kunit_test_suit_name, TEST_CASES);
+    // ```
+    //
+    // Non-function items (e.g. imports) are preserved.
+    for item in module_items {
+        let Item::Fn(mut f) = item else {
+            processed_items.push(item);
+            continue;
+        };
+
+        if f.attrs
+            .extract_if(.., |attr| attr.path().is_ident("test"))
+            .count()
+            == 0
+        {
+            processed_items.push(Item::Fn(f));
+            continue;
+        }
+
+        let test = f.sig.ident.clone();
+
+        // Retrieve `#[cfg]` applied on the function which needs to be present on derived items too.
+        let cfg_attrs: Vec<_> = f
+            .attrs
+            .iter()
+            .filter(|attr| attr.path().is_ident("cfg"))
+            .cloned()
+            .collect();
+
+        // Before the test, override usual `assert!` and `assert_eq!` macros with ones that call
+        // KUnit instead.
+        let test_str = test.to_string();
+        let path = CString::new(crate::helpers::file()).expect("file path cannot contain NUL");
+        processed_items.push(parse_quote! {
+            #[allow(unused)]
+            macro_rules! assert {
+                ($cond:expr $(,)?) => {{
+                    kernel::kunit_assert!(#test_str, #path, 0, $cond);
+                }}
+            }
+        });
+        processed_items.push(parse_quote! {
+            #[allow(unused)]
+            macro_rules! assert_eq {
+                ($left:expr, $right:expr $(,)?) => {{
+                    kernel::kunit_assert_eq!(#test_str, #path, 0, $left, $right);
+                }}
+            }
+        });
+
+        // Add back the test item.
+        processed_items.push(Item::Fn(f));
+
+        let kunit_wrapper_fn_name = format_ident!("kunit_rust_wrapper_{test}");
+        let test_cstr = LitCStr::new(
+            &CString::new(test_str.as_str()).expect("identifier cannot contain NUL"),
+            test.span(),
+        );
+        processed_items.push(parse_quote! {
+            unsafe extern "C" fn #kunit_wrapper_fn_name(_test: *mut ::kernel::bindings::kunit) {
+                (*_test).status = ::kernel::bindings::kunit_status_KUNIT_SKIPPED;
+
+                // Append any `cfg` attributes the user might have written on their tests so we
+                // don't attempt to call them when they are `cfg`'d out. An extra `use` is used
+                // here to reduce the length of the assert message.
+                #(#cfg_attrs)*
+                {
+                    (*_test).status = ::kernel::bindings::kunit_status_KUNIT_SUCCESS;
+                    use ::kernel::kunit::is_test_result_ok;
+                    assert!(is_test_result_ok(#test()));
+                }
+            }
+        });
+
+        test_cases.push(quote!(
+            ::kernel::kunit::kunit_case(#test_cstr, #kunit_wrapper_fn_name)
+        ));
+    }
+
+    let num_tests_plus_1 = test_cases.len() + 1;
+    processed_items.push(parse_quote! {
+        static mut TEST_CASES: [::kernel::bindings::kunit_case; #num_tests_plus_1] = [
+            #(#test_cases,)*
+            ::pin_init::zeroed(),
+        ];
+    });
+    processed_items.push(parse_quote! {
+        ::kernel::kunit_unsafe_test_suite!(#test_suite, TEST_CASES);
+    });
+
+    module.content = Some((module_brace, processed_items));
+    Ok(module.to_token_stream())
+}