lib/stackdepot: rename hash table constants and variables

Give more meaningful names to hash table-related constants and variables:

1. Rename STACK_HASH_SCALE to STACK_HASH_TABLE_SCALE to point out that it
   is related to scaling the hash table.

2. Rename STACK_HASH_ORDER_MIN/MAX to STACK_BUCKET_NUMBER_ORDER_MIN/MAX
   to point out that it is related to the number of hash table buckets.

3. Rename stack_hash_order to stack_bucket_number_order for the same
   reason as #2.

No functional changes.

Link: https://lkml.kernel.org/r/f166dd6f3cb2378aea78600714393dd568c33ee9.1676063693.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/stackdepot.c

@@ -76,17 +76,17 @@ static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_ST
 static bool __stack_depot_early_init_passed __initdata;
 
 /* Use one hash table bucket per 16 KB of memory. */
-#define STACK_HASH_SCALE	14
+#define STACK_HASH_TABLE_SCALE 14
 /* Limit the number of buckets between 4K and 1M. */
-#define STACK_HASH_ORDER_MIN	12
-#define STACK_HASH_ORDER_MAX	20
+#define STACK_BUCKET_NUMBER_ORDER_MIN 12
+#define STACK_BUCKET_NUMBER_ORDER_MAX 20
 /* Initial seed for jhash2. */
 #define STACK_HASH_SEED 0x9747b28c
 
 /* Hash table of pointers to stored stack traces. */
 static struct stack_record **stack_table;
 /* Fixed order of the number of table buckets. Used when KASAN is enabled. */
-static unsigned int stack_hash_order;
+static unsigned int stack_bucket_number_order;
 /* Hash mask for indexing the table. */
 static unsigned int stack_hash_mask;
 
@@ -137,28 +137,28 @@ int __init stack_depot_early_init(void)
 	 * in fuzzing scenarios, which leads to a large number of different
 	 * stack traces being stored in stack depot.
 	 */
-	if (kasan_enabled() && !stack_hash_order)
-		stack_hash_order = STACK_HASH_ORDER_MAX;
+	if (kasan_enabled() && !stack_bucket_number_order)
+		stack_bucket_number_order = STACK_BUCKET_NUMBER_ORDER_MAX;
 
 	if (!__stack_depot_early_init_requested || stack_depot_disabled)
 		return 0;
 
 	/*
-	 * If stack_hash_order is not set, leave entries as 0 to rely on the
-	 * automatic calculations performed by alloc_large_system_hash.
+	 * If stack_bucket_number_order is not set, leave entries as 0 to rely
+	 * on the automatic calculations performed by alloc_large_system_hash.
 	 */
-	if (stack_hash_order)
-		entries = 1UL << stack_hash_order;
+	if (stack_bucket_number_order)
+		entries = 1UL << stack_bucket_number_order;
 	pr_info("allocating hash table via alloc_large_system_hash\n");
 	stack_table = alloc_large_system_hash("stackdepot",
 						sizeof(struct stack_record *),
 						entries,
-						STACK_HASH_SCALE,
+						STACK_HASH_TABLE_SCALE,
 						HASH_EARLY | HASH_ZERO,
 						NULL,
 						&stack_hash_mask,
-						1UL << STACK_HASH_ORDER_MIN,
-						1UL << STACK_HASH_ORDER_MAX);
+						1UL << STACK_BUCKET_NUMBER_ORDER_MIN,
+						1UL << STACK_BUCKET_NUMBER_ORDER_MAX);
 	if (!stack_table) {
 		pr_err("hash table allocation failed, disabling\n");
 		stack_depot_disabled = true;
@@ -181,13 +181,13 @@ int stack_depot_init(void)
 		goto out_unlock;
 
 	/*
-	 * Similarly to stack_depot_early_init, use stack_hash_order
+	 * Similarly to stack_depot_early_init, use stack_bucket_number_order
 	 * if assigned, and rely on automatic scaling otherwise.
 	 */
-	if (stack_hash_order) {
-		entries = 1UL << stack_hash_order;
+	if (stack_bucket_number_order) {
+		entries = 1UL << stack_bucket_number_order;
 	} else {
-		int scale = STACK_HASH_SCALE;
+		int scale = STACK_HASH_TABLE_SCALE;
 
 		entries = nr_free_buffer_pages();
 		entries = roundup_pow_of_two(entries);
@@ -198,10 +198,10 @@ int stack_depot_init(void)
 			entries <<= (PAGE_SHIFT - scale);
 	}
 
-	if (entries < 1UL << STACK_HASH_ORDER_MIN)
-		entries = 1UL << STACK_HASH_ORDER_MIN;
-	if (entries > 1UL << STACK_HASH_ORDER_MAX)
-		entries = 1UL << STACK_HASH_ORDER_MAX;
+	if (entries < 1UL << STACK_BUCKET_NUMBER_ORDER_MIN)
+		entries = 1UL << STACK_BUCKET_NUMBER_ORDER_MIN;
+	if (entries > 1UL << STACK_BUCKET_NUMBER_ORDER_MAX)
+		entries = 1UL << STACK_BUCKET_NUMBER_ORDER_MAX;
 
 	pr_info("allocating hash table of %lu entries via kvcalloc\n", entries);
 	stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL);