[PATCH v2 1/1] mseal: remove can_do_mseal()

[jeffxu@chromium.org]

From: Jeff Xu <jeffxu@chromium.org>

No code logic change.

can_do_mseal() is called exclusively by mseal.c, and mseal.c is compiled
only when CONFIG_64BIT flag is set in makefile.  Therefore, it is
unnecessary to have 32 bit stub function in the header file, remove
this function and merge the logic into do_mseal().

Link: https://lkml.kernel.org/r/20241206013934.2782793-1-jeffxu@google.com
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/internal.h | 16 ----------------
 mm/mseal.c    |  6 +++---
 2 files changed, 3 insertions(+), 19 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index 74dc1c48fa31..5e4ef5ce9c0a 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1457,22 +1457,6 @@ void __meminit __init_single_page(struct page *page, unsigned long pfn,
 unsigned long shrink_slab(gfp_t gfp_mask, int nid, struct mem_cgroup *memcg,
 			  int priority);
 
-#ifdef CONFIG_64BIT
-static inline int can_do_mseal(unsigned long flags)
-{
-	if (flags)
-		return -EINVAL;
-
-	return 0;
-}
-
-#else
-static inline int can_do_mseal(unsigned long flags)
-{
-	return -EPERM;
-}
-#endif
-
 #ifdef CONFIG_SHRINKER_DEBUG
 static inline __printf(2, 0) int shrinker_debugfs_name_alloc(
 			struct shrinker *shrinker, const char *fmt, va_list ap)
diff --git a/mm/mseal.c b/mm/mseal.c
index 81d6e980e8a9..c27197ac04e8 100644
--- a/mm/mseal.c
+++ b/mm/mseal.c
@@ -217,9 +217,9 @@ int do_mseal(unsigned long start, size_t len_in, unsigned long flags)
 	unsigned long end;
 	struct mm_struct *mm = current->mm;
 
-	ret = can_do_mseal(flags);
-	if (ret)
-		return ret;
+	/* Verify flags not set. */
+	if (flags)
+		return -EINVAL;
 
 	start = untagged_addr(start);
 	if (!PAGE_ALIGNED(start))
-- 
2.47.0.338.g60cca15819-goog