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authorAndi Shyti <andi.shyti@linux.intel.com>2026-08-22 14:19:12 +0200
committerAndi Shyti <andi.shyti@linux.intel.com>2026-08-22 14:19:34 +0200
commitd576a9561a1c80ae593539fb0ce0743d66825ac2 (patch)
tree68f6de7e06b350afa42edeea2f7f33f086014597 /lib/percpu_test.c
downloadlinux-stable-d576a9561a1c80ae593539fb0ce0743d66825ac2.tar.gz
linux-stable-d576a9561a1c80ae593539fb0ce0743d66825ac2.zip
Merge tag 'rust-i2c-for-7.3' into i2c/i2cgrafted
i2c: rust: mark I2cAdapter methods as inline A single cleanup for the Rust I2C abstractions, targeting 7.3. `I2cAdapter::get`, `inc_ref`, and `dec_ref` are trivial wrappers around `i2c_get_adapter`/`i2c_put_adapter` and were showing up as their own symbols in the build. Mark them `#[inline]` so they get folded into their callers instead. Signed-off-by: Igor Korotin <igor.korotin@linux.dev> * tag 'rust-i2c-for-7.3': i2c: rust: mark I2cAdapter methods as inline
Diffstat (limited to 'lib/percpu_test.c')
-rw-r--r--lib/percpu_test.c148
1 files changed, 148 insertions, 0 deletions
diff --git a/lib/percpu_test.c b/lib/percpu_test.c
new file mode 100644
index 000000000..ce7124b16
--- /dev/null
+++ b/lib/percpu_test.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/limits.h>
+#include <linux/module.h>
+
+/* validate @native and @pcp counter values match @expected */
+#define CHECK(native, pcp, expected) \
+ do { \
+ WARN((native) != (expected), \
+ "raw %ld (0x%lx) != expected %lld (0x%llx)", \
+ (native), (native), \
+ (long long)(expected), (long long)(expected)); \
+ WARN(__this_cpu_read(pcp) != (expected), \
+ "pcp %ld (0x%lx) != expected %lld (0x%llx)", \
+ __this_cpu_read(pcp), __this_cpu_read(pcp), \
+ (long long)(expected), (long long)(expected)); \
+ } while (0)
+
+static DEFINE_PER_CPU(long, long_counter);
+static DEFINE_PER_CPU(unsigned long, ulong_counter);
+
+static int __init percpu_test_init(void)
+{
+ /*
+ * volatile prevents compiler from optimizing it uses, otherwise the
+ * +ul_one/-ul_one below would replace with inc/dec instructions.
+ */
+ volatile unsigned int ui_one = 1;
+ unsigned long long ull = 0;
+ unsigned long ul = 0;
+ long l = 0;
+
+ pr_info("percpu test start\n");
+
+ preempt_disable();
+
+ l += -1;
+ __this_cpu_add(long_counter, -1);
+ CHECK(l, long_counter, -1);
+
+ l += 1;
+ __this_cpu_add(long_counter, 1);
+ CHECK(l, long_counter, 0);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul += 1UL;
+ __this_cpu_add(ulong_counter, 1UL);
+ CHECK(ul, ulong_counter, 1);
+
+ ul += -1UL;
+ __this_cpu_add(ulong_counter, -1UL);
+ CHECK(ul, ulong_counter, 0);
+
+ ul += -(unsigned long)1;
+ __this_cpu_add(ulong_counter, -(unsigned long)1);
+ CHECK(ul, ulong_counter, -1);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul -= 1;
+ __this_cpu_dec(ulong_counter);
+ CHECK(ul, ulong_counter, -1);
+ CHECK(ul, ulong_counter, ULONG_MAX);
+
+ l += -ui_one;
+ __this_cpu_add(long_counter, -ui_one);
+ CHECK(l, long_counter, 0xffffffff);
+
+ l += ui_one;
+ __this_cpu_add(long_counter, ui_one);
+ CHECK(l, long_counter, (long)0x100000000LL);
+
+
+ l = 0;
+ __this_cpu_write(long_counter, 0);
+
+ l -= ui_one;
+ __this_cpu_sub(long_counter, ui_one);
+ CHECK(l, long_counter, -1);
+
+ l = 0;
+ __this_cpu_write(long_counter, 0);
+
+ l += ui_one;
+ __this_cpu_add(long_counter, ui_one);
+ CHECK(l, long_counter, 1);
+
+ l += -ui_one;
+ __this_cpu_add(long_counter, -ui_one);
+ CHECK(l, long_counter, (long)0x100000000LL);
+
+ l = 0;
+ __this_cpu_write(long_counter, 0);
+
+ l -= ui_one;
+ this_cpu_sub(long_counter, ui_one);
+ CHECK(l, long_counter, -1);
+ CHECK(l, long_counter, ULONG_MAX);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul += ui_one;
+ __this_cpu_add(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, 1);
+
+ ul = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul -= ui_one;
+ __this_cpu_sub(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, -1);
+ CHECK(ul, ulong_counter, ULONG_MAX);
+
+ ul = ull = 0;
+ __this_cpu_write(ulong_counter, 0);
+
+ ul = ull += UINT_MAX;
+ __this_cpu_add(ulong_counter, ull);
+ CHECK(ul, ulong_counter, UINT_MAX);
+
+ ul = 3;
+ __this_cpu_write(ulong_counter, 3);
+
+ ul = this_cpu_sub_return(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, 2);
+
+ ul = __this_cpu_sub_return(ulong_counter, ui_one);
+ CHECK(ul, ulong_counter, 1);
+
+ preempt_enable();
+
+ pr_info("percpu test done\n");
+ return -EAGAIN; /* Fail will directly unload the module */
+}
+
+static void __exit percpu_test_exit(void)
+{
+}
+
+module_init(percpu_test_init)
+module_exit(percpu_test_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Greg Thelen");
+MODULE_DESCRIPTION("percpu operations test");