From bdfa89c489296f092751fcee23b5d171c9fdc7f5 Mon Sep 17 00:00:00 2001 From: Tiffany Yang Date: Mon, 14 Jul 2025 11:53:16 -0700 Subject: [PATCH] kunit: test: Export kunit_attach_mm() Tests can allocate from virtual memory using kunit_vm_mmap(), which transparently creates and attaches an mm_struct to the test runner if one is not already attached. This is suitable for most cases, except for when the code under test must access a task's mm before performing an mmap. Expose kunit_attach_mm() as part of the interface for those cases. This does not change the existing behavior. Cc: David Gow Signed-off-by: Tiffany Yang Reviewed-by: Carlos Llamas Link: https://lore.kernel.org/r/20250714185321.2417234-4-ynaffit@google.com Signed-off-by: Greg Kroah-Hartman --- include/kunit/test.h | 12 ++++++++++++ lib/kunit/user_alloc.c | 4 ++-- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/include/kunit/test.h b/include/kunit/test.h index 39c768f87dc9f..d958ee53050e1 100644 --- a/include/kunit/test.h +++ b/include/kunit/test.h @@ -531,6 +531,18 @@ static inline char *kunit_kstrdup(struct kunit *test, const char *str, gfp_t gfp */ const char *kunit_kstrdup_const(struct kunit *test, const char *str, gfp_t gfp); +/** + * kunit_attach_mm() - Create and attach a new mm if it doesn't already exist. + * + * Allocates a &struct mm_struct and attaches it to @current. In most cases, call + * kunit_vm_mmap() without calling kunit_attach_mm() directly. Only necessary when + * code under test accesses the mm before executing the mmap (e.g., to perform + * additional initialization beforehand). + * + * Return: 0 on success, -errno on failure. + */ +int kunit_attach_mm(void); + /** * kunit_vm_mmap() - Allocate KUnit-tracked vm_mmap() area * @test: The test context object. diff --git a/lib/kunit/user_alloc.c b/lib/kunit/user_alloc.c index 46951be018be2..b8cac765e6204 100644 --- a/lib/kunit/user_alloc.c +++ b/lib/kunit/user_alloc.c @@ -22,8 +22,7 @@ struct kunit_vm_mmap_params { unsigned long offset; }; -/* Create and attach a new mm if it doesn't already exist. */ -static int kunit_attach_mm(void) +int kunit_attach_mm(void) { struct mm_struct *mm; @@ -49,6 +48,7 @@ static int kunit_attach_mm(void) return 0; } +EXPORT_SYMBOL_GPL(kunit_attach_mm); static int kunit_vm_mmap_init(struct kunit_resource *res, void *context) { -- 2.47.2