[PATCH 1/4] mm/madvise: use is_memory_failure() from madvise_do_behavior()

[SeongJae Park <sj@kernel.org>]

To reduce redundant open-coded checks of CONFIG_MEMORY_FAILURE and
MADV_{HWPOISON,SOFT_OFFLINE} in madvise_[un]lock(), is_memory_failure()
is introduced.  madvise_do_behavior() is still doing the same open-coded
check, though.  Use is_memory_failure() instead.

To avoid build failure on !CONFIG_MEMORY_FAILURE case, implement an
empty madvise_inject_error() under the config.  Also move the definition
of is_memory_failure() inside #ifdef CONFIG_MEMORY_FAILURE clause for
madvise_inject_error() definition, to reduce duplicated ifdef clauses.

Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 mm/madvise.c | 49 +++++++++++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 388dc289b5d1..c3ab1f283b18 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1392,7 +1392,32 @@ static int madvise_inject_error(int behavior,
 
 	return 0;
 }
-#endif
+
+static bool is_memory_failure(int behavior)
+{
+	switch (behavior) {
+	case MADV_HWPOISON:
+	case MADV_SOFT_OFFLINE:
+		return true;
+	default:
+		return false;
+	}
+}
+
+#else
+
+static int madvise_inject_error(int behavior,
+		unsigned long start, unsigned long end)
+{
+	return 0;
+}
+
+static bool is_memory_failure(int behavior)
+{
+	return false;
+}
+
+#endif	/* CONFIG_MEMORY_FAILURE */
 
 static bool
 madvise_behavior_valid(int behavior)
@@ -1569,24 +1594,6 @@ int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
 }
 #endif /* CONFIG_ANON_VMA_NAME */
 
-#ifdef CONFIG_MEMORY_FAILURE
-static bool is_memory_failure(int behavior)
-{
-	switch (behavior) {
-	case MADV_HWPOISON:
-	case MADV_SOFT_OFFLINE:
-		return true;
-	default:
-		return false;
-	}
-}
-#else
-static bool is_memory_failure(int behavior)
-{
-	return false;
-}
-#endif
-
 static int madvise_lock(struct mm_struct *mm, int behavior)
 {
 	if (is_memory_failure(behavior))
@@ -1640,10 +1647,8 @@ static int madvise_do_behavior(struct mm_struct *mm,
 	unsigned long end;
 	int error;
 
-#ifdef CONFIG_MEMORY_FAILURE
-	if (behavior == MADV_HWPOISON || behavior == MADV_SOFT_OFFLINE)
+	if (is_memory_failure(behavior))
 		return madvise_inject_error(behavior, start, start + len_in);
-#endif
 	start = untagged_addr_remote(mm, start);
 	end = start + len;
 
-- 
2.39.5