kunit: remove va_format from kunit_assert

The concern is that having a lot of redundant fields in kunit_assert can
blow up stack usage if the compiler doesn't optimize them away [1].

The comment on this field implies that it was meant to be initialized
when the expect/assert was declared, but this only happens when we run
kunit_do_failed_assertion().

We don't need to access it outside of that function, so move it out of
the struct and make it a local variable there.

This change also takes the chance to reduce the number of macros by
inlining the now simplified KUNIT_INIT_ASSERT_STRUCT() macro.

[1] https://groups.google.com/g/kunit-dev/c/i3fZXgvBrfA/m/VULQg1z6BAAJ

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

diff --git a/include/kunit/assert.h b/include/kunit/assert.h
index f2b3ae5cc2deeaa7c3e26390b6552a29e367e82c..0b3704db54b69dca92824516d08dac87c17868d1 100644 (file)
--- a/include/kunit/assert.h
+++ b/include/kunit/assert.h
@@ -42,44 +42,21 @@ struct kunit_loc {
 
 /**
  * struct kunit_assert - Data for printing a failed assertion or expectation.
- * @message: an optional message to provide additional context.
  * @format: a function which formats the data in this kunit_assert to a string.
  *
  * Represents a failed expectation/assertion. Contains all the data necessary to
  * format a string to a user reporting the failure.
  */
 struct kunit_assert {
-       struct va_format message;
        void (*format)(const struct kunit_assert *assert,
+                      const struct va_format *message,
                       struct string_stream *stream);
 };
 
-/**
- * KUNIT_INIT_VA_FMT_NULL - Default initializer for struct va_format.
- *
- * Used inside a struct initialization block to initialize struct va_format to
- * default values where fmt and va are null.
- */
-#define KUNIT_INIT_VA_FMT_NULL { .fmt = NULL, .va = NULL }
-
-/**
- * KUNIT_INIT_ASSERT_STRUCT() - Initializer for a &struct kunit_assert.
- * @fmt: The formatting function which builds a string out of this kunit_assert.
- *
- * The base initializer for a &struct kunit_assert.
- */
-#define KUNIT_INIT_ASSERT_STRUCT(fmt) {                                               \
-       .message = KUNIT_INIT_VA_FMT_NULL,                                     \
-       .format = fmt                                                          \
-}
-
 void kunit_assert_prologue(const struct kunit_loc *loc,
                           enum kunit_assert_type type,
                           struct string_stream *stream);
 
-void kunit_assert_print_msg(const struct kunit_assert *assert,
-                           struct string_stream *stream);
-
 /**
  * struct kunit_fail_assert - Represents a plain fail expectation/assertion.
  * @assert: The parent of this type.
@@ -91,6 +68,7 @@ struct kunit_fail_assert {
 };
 
 void kunit_fail_assert_format(const struct kunit_assert *assert,
+                             const struct va_format *message,
                              struct string_stream *stream);
 
 /**
@@ -100,7 +78,7 @@ void kunit_fail_assert_format(const struct kunit_assert *assert,
  * KUNIT_EXPECT_* and KUNIT_ASSERT_* macros.
  */
 #define KUNIT_INIT_FAIL_ASSERT_STRUCT {                                        \
-       .assert = KUNIT_INIT_ASSERT_STRUCT(kunit_fail_assert_format)    \
+       .assert = { .format = kunit_fail_assert_format },               \
 }
 
 /**
@@ -120,6 +98,7 @@ struct kunit_unary_assert {
 };
 
 void kunit_unary_assert_format(const struct kunit_assert *assert,
+                              const struct va_format *message,
                               struct string_stream *stream);
 
 /**
@@ -131,7 +110,7 @@ void kunit_unary_assert_format(const struct kunit_assert *assert,
  * KUNIT_EXPECT_* and KUNIT_ASSERT_* macros.
  */
 #define KUNIT_INIT_UNARY_ASSERT_STRUCT(cond, expect_true) {                   \
-       .assert = KUNIT_INIT_ASSERT_STRUCT(kunit_unary_assert_format),         \
+       .assert = { .format = kunit_unary_assert_format },                     \
        .condition = cond,                                                     \
        .expected_true = expect_true                                           \
 }
@@ -153,6 +132,7 @@ struct kunit_ptr_not_err_assert {
 };
 
 void kunit_ptr_not_err_assert_format(const struct kunit_assert *assert,
+                                    const struct va_format *message,
                                     struct string_stream *stream);
 
 /**
@@ -165,7 +145,7 @@ void kunit_ptr_not_err_assert_format(const struct kunit_assert *assert,
  * KUNIT_EXPECT_* and KUNIT_ASSERT_* macros.
  */
 #define KUNIT_INIT_PTR_NOT_ERR_STRUCT(txt, val) {                             \
-       .assert = KUNIT_INIT_ASSERT_STRUCT(kunit_ptr_not_err_assert_format),   \
+       .assert = { .format = kunit_ptr_not_err_assert_format },               \
        .text = txt,                                                           \
        .value = val                                                           \
 }
@@ -194,6 +174,7 @@ struct kunit_binary_assert {
 };
 
 void kunit_binary_assert_format(const struct kunit_assert *assert,
+                               const struct va_format *message,
                                struct string_stream *stream);
 
 /**
@@ -213,7 +194,7 @@ void kunit_binary_assert_format(const struct kunit_assert *assert,
                                        left_val,                              \
                                        right_str,                             \
                                        right_val) {                           \
-       .assert = KUNIT_INIT_ASSERT_STRUCT(kunit_binary_assert_format),        \
+       .assert = { .format = kunit_binary_assert_format },                    \
        .operation = op_str,                                                   \
        .left_text = left_str,                                                 \
        .left_value = left_val,                                                \
@@ -245,6 +226,7 @@ struct kunit_binary_ptr_assert {
 };
 
 void kunit_binary_ptr_assert_format(const struct kunit_assert *assert,
+                                   const struct va_format *message,
                                    struct string_stream *stream);
 
 /**
@@ -265,7 +247,7 @@ void kunit_binary_ptr_assert_format(const struct kunit_assert *assert,
                                            left_val,                          \
                                            right_str,                         \
                                            right_val) {                       \
-       .assert = KUNIT_INIT_ASSERT_STRUCT(kunit_binary_ptr_assert_format),    \
+       .assert = { .format = kunit_binary_ptr_assert_format },                \
        .operation = op_str,                                                   \
        .left_text = left_str,                                                 \
        .left_value = left_val,                                                \
@@ -297,6 +279,7 @@ struct kunit_binary_str_assert {
 };
 
 void kunit_binary_str_assert_format(const struct kunit_assert *assert,
+                                   const struct va_format *message,
                                    struct string_stream *stream);
 
 /**
@@ -316,7 +299,7 @@ void kunit_binary_str_assert_format(const struct kunit_assert *assert,
                                            left_val,                          \
                                            right_str,                         \
                                            right_val) {                       \
-       .assert = KUNIT_INIT_ASSERT_STRUCT(kunit_binary_str_assert_format),    \
+       .assert = { .format = kunit_binary_str_assert_format },                \
        .operation = op_str,                                                   \
        .left_text = left_str,                                                 \
        .left_value = left_val,                                                \

diff --git a/lib/kunit/assert.c b/lib/kunit/assert.c
index 9f4492a8e24eea974be164d09a9a5619c1c27a29..c9c7ee0dfafabe0afe834e8e9806080cbd9bca51 100644 (file)
--- a/lib/kunit/assert.c
+++ b/lib/kunit/assert.c
@@ -30,22 +30,23 @@ void kunit_assert_prologue(const struct kunit_loc *loc,
 }
 EXPORT_SYMBOL_GPL(kunit_assert_prologue);
 
-void kunit_assert_print_msg(const struct kunit_assert *assert,
-                           struct string_stream *stream)
+static void kunit_assert_print_msg(const struct va_format *message,
+                                  struct string_stream *stream)
 {
-       if (assert->message.fmt)
-               string_stream_add(stream, "\n%pV", &assert->message);
+       if (message->fmt)
+               string_stream_add(stream, "\n%pV", message);
 }
-EXPORT_SYMBOL_GPL(kunit_assert_print_msg);
 
 void kunit_fail_assert_format(const struct kunit_assert *assert,
+                             const struct va_format *message,
                              struct string_stream *stream)
 {
-       string_stream_add(stream, "%pV", &assert->message);
+       string_stream_add(stream, "%pV", message);
 }
 EXPORT_SYMBOL_GPL(kunit_fail_assert_format);
 
 void kunit_unary_assert_format(const struct kunit_assert *assert,
+                              const struct va_format *message,
                               struct string_stream *stream)
 {
        struct kunit_unary_assert *unary_assert;
@@ -60,11 +61,12 @@ void kunit_unary_assert_format(const struct kunit_assert *assert,
                string_stream_add(stream,
                                  KUNIT_SUBTEST_INDENT "Expected %s to be false, but is true\n",
                                  unary_assert->condition);
-       kunit_assert_print_msg(assert, stream);
+       kunit_assert_print_msg(message, stream);
 }
 EXPORT_SYMBOL_GPL(kunit_unary_assert_format);
 
 void kunit_ptr_not_err_assert_format(const struct kunit_assert *assert,
+                                    const struct va_format *message,
                                     struct string_stream *stream)
 {
        struct kunit_ptr_not_err_assert *ptr_assert;
@@ -82,7 +84,7 @@ void kunit_ptr_not_err_assert_format(const struct kunit_assert *assert,
                                  ptr_assert->text,
                                  PTR_ERR(ptr_assert->value));
        }
-       kunit_assert_print_msg(assert, stream);
+       kunit_assert_print_msg(message, stream);
 }
 EXPORT_SYMBOL_GPL(kunit_ptr_not_err_assert_format);
 
@@ -110,6 +112,7 @@ static bool is_literal(struct kunit *test, const char *text, long long value,
 }
 
 void kunit_binary_assert_format(const struct kunit_assert *assert,
+                               const struct va_format *message,
                                struct string_stream *stream)
 {
        struct kunit_binary_assert *binary_assert;
@@ -132,11 +135,12 @@ void kunit_binary_assert_format(const struct kunit_assert *assert,
                string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %lld",
                                  binary_assert->right_text,
                                  binary_assert->right_value);
-       kunit_assert_print_msg(assert, stream);
+       kunit_assert_print_msg(message, stream);
 }
 EXPORT_SYMBOL_GPL(kunit_binary_assert_format);
 
 void kunit_binary_ptr_assert_format(const struct kunit_assert *assert,
+                                   const struct va_format *message,
                                    struct string_stream *stream)
 {
        struct kunit_binary_ptr_assert *binary_assert;
@@ -155,7 +159,7 @@ void kunit_binary_ptr_assert_format(const struct kunit_assert *assert,
        string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == %px",
                          binary_assert->right_text,
                          binary_assert->right_value);
-       kunit_assert_print_msg(assert, stream);
+       kunit_assert_print_msg(message, stream);
 }
 EXPORT_SYMBOL_GPL(kunit_binary_ptr_assert_format);
 
@@ -176,6 +180,7 @@ static bool is_str_literal(const char *text, const char *value)
 }
 
 void kunit_binary_str_assert_format(const struct kunit_assert *assert,
+                                   const struct va_format *message,
                                    struct string_stream *stream)
 {
        struct kunit_binary_str_assert *binary_assert;
@@ -196,6 +201,6 @@ void kunit_binary_str_assert_format(const struct kunit_assert *assert,
                string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s == \"%s\"",
                                  binary_assert->right_text,
                                  binary_assert->right_value);
-       kunit_assert_print_msg(assert, stream);
+       kunit_assert_print_msg(message, stream);
 }
 EXPORT_SYMBOL_GPL(kunit_binary_str_assert_format);

diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index 7dec3248562f1874cac0b740b89df114be85bc02..3bca3bf5c15b19e34f1bc7a622257c0cec89c37e 100644 (file)
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -241,7 +241,8 @@ static void kunit_print_string_stream(struct kunit *test,
 }
 
 static void kunit_fail(struct kunit *test, const struct kunit_loc *loc,
-                      enum kunit_assert_type type, struct kunit_assert *assert)
+                      enum kunit_assert_type type, struct kunit_assert *assert,
+                      const struct va_format *message)
 {
        struct string_stream *stream;
 
@@ -257,7 +258,7 @@ static void kunit_fail(struct kunit *test, const struct kunit_loc *loc,
        }
 
        kunit_assert_prologue(loc, type, stream);
-       assert->format(assert, stream);
+       assert->format(assert, message, stream);
 
        kunit_print_string_stream(test, stream);
 
@@ -284,12 +285,13 @@ void kunit_do_failed_assertion(struct kunit *test,
                               const char *fmt, ...)
 {
        va_list args;
+       struct va_format message;
        va_start(args, fmt);
 
-       assert->message.fmt = fmt;
-       assert->message.va = &args;
+       message.fmt = fmt;
+       message.va = &args;
 
-       kunit_fail(test, loc, type, assert);
+       kunit_fail(test, loc, type, assert, &message);
 
        va_end(args);