lib/stackdepot: drop valid bit from handles

Stack depot doesn't use the valid bit in handles in any way, so drop it.

Link: https://lkml.kernel.org/r/34969bba2ca6e012c6ad071767197dee64dc5723.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/stackdepot.c

@@ -32,13 +32,12 @@
 
 #define DEPOT_HANDLE_BITS (sizeof(depot_stack_handle_t) * 8)
 
-#define DEPOT_VALID_BITS 1
 #define DEPOT_POOL_ORDER 2 /* Pool size order, 4 pages */
 #define DEPOT_POOL_SIZE (1LL << (PAGE_SHIFT + DEPOT_POOL_ORDER))
 #define DEPOT_STACK_ALIGN 4
 #define DEPOT_OFFSET_BITS (DEPOT_POOL_ORDER + PAGE_SHIFT - DEPOT_STACK_ALIGN)
-#define DEPOT_POOL_INDEX_BITS (DEPOT_HANDLE_BITS - DEPOT_VALID_BITS - \
-			       DEPOT_OFFSET_BITS - STACK_DEPOT_EXTRA_BITS)
+#define DEPOT_POOL_INDEX_BITS (DEPOT_HANDLE_BITS - DEPOT_OFFSET_BITS - \
+			       STACK_DEPOT_EXTRA_BITS)
 #define DEPOT_POOLS_CAP 8192
 #define DEPOT_MAX_POOLS \
 	(((1LL << (DEPOT_POOL_INDEX_BITS)) < DEPOT_POOLS_CAP) ? \
@@ -50,7 +49,6 @@ union handle_parts {
 	struct {
 		u32 pool_index	: DEPOT_POOL_INDEX_BITS;
 		u32 offset	: DEPOT_OFFSET_BITS;
-		u32 valid	: DEPOT_VALID_BITS;
 		u32 extra	: STACK_DEPOT_EXTRA_BITS;
 	};
 };
@@ -309,7 +307,6 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc)
 	stack->size = size;
 	stack->handle.pool_index = pool_index;
 	stack->handle.offset = pool_offset >> DEPOT_STACK_ALIGN;
-	stack->handle.valid = 1;
 	stack->handle.extra = 0;
 	memcpy(stack->entries, entries, flex_array_size(stack, entries, size));
 	pool_offset += required_size;