set_tag() already ignores the tag for the generic mode, so just call it
as is. Add a check for the generic mode to assign_tag(), and simplify its
call in ____kasan_kmalloc().

Signed-off-by: Andrey Konovalov <[email protected]>
Reviewed-by: Dmitry Vyukov <[email protected]>
Reviewed-by: Marco Elver <[email protected]>
Link: 
https://linux-review.googlesource.com/id/I18905ca78fb4a3d60e1a34a4ca00247272480438
---
 mm/kasan/common.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 1a88e4005181..821678a58ac6 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -234,6 +234,9 @@ void __kasan_poison_object_data(struct kmem_cache *cache, 
void *object)
 static u8 assign_tag(struct kmem_cache *cache, const void *object,
                        bool init, bool keep_tag)
 {
+       if (IS_ENABLED(CONFIG_KASAN_GENERIC))
+               return 0xff;
+
        /*
         * 1. When an object is kmalloc()'ed, two hooks are called:
         *    kasan_slab_alloc() and kasan_kmalloc(). We assign the
@@ -276,8 +279,8 @@ void * __must_check __kasan_init_slab_obj(struct kmem_cache 
*cache,
                __memset(alloc_meta, 0, sizeof(*alloc_meta));
        }
 
-       if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || 
IS_ENABLED(CONFIG_KASAN_HW_TAGS))
-               object = set_tag(object, assign_tag(cache, object, true, 
false));
+       /* Tag is ignored in set_tag() without CONFIG_KASAN_SW/HW_TAGS */
+       object = set_tag(object, assign_tag(cache, object, true, false));
 
        return (void *)object;
 }
@@ -364,7 +367,7 @@ static void *____kasan_kmalloc(struct kmem_cache *cache, 
const void *object,
 {
        unsigned long redzone_start;
        unsigned long redzone_end;
-       u8 tag = 0xff;
+       u8 tag;
 
        if (gfpflags_allow_blocking(flags))
                quarantine_reduce();
@@ -379,9 +382,7 @@ static void *____kasan_kmalloc(struct kmem_cache *cache, 
const void *object,
                                KASAN_GRANULE_SIZE);
        redzone_end = round_up((unsigned long)object + cache->object_size,
                                KASAN_GRANULE_SIZE);
-
-       if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) || 
IS_ENABLED(CONFIG_KASAN_HW_TAGS))
-               tag = assign_tag(cache, object, false, keep_tag);
+       tag = assign_tag(cache, object, false, keep_tag);
 
        /* Tag is ignored in set_tag without CONFIG_KASAN_SW/HW_TAGS */
        unpoison_range(set_tag(object, tag), size);
-- 
2.29.2.454.gaff20da3a2-goog

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