From:   andrey.konovalov@linux.dev
To:     Marco Elver <elver@google.com>,
        Alexander Potapenko <glider@google.com>
Cc:     Andrey Konovalov <andreyknvl@gmail.com>,
        Vlastimil Babka <vbabka@suse.cz>, kasan-dev@googlegroups.com,
        Evgenii Stepanov <eugenis@google.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v2 07/18] lib/stackdepot: reorder and annotate global variables
Date:   Fri, 10 Feb 2023 22:15:55 +0100
Message-Id: <5606a6c70659065a25bee59cd10e57fc60bb4110.1676063693.git.andreyknvl@google.com>
In-Reply-To: <cover.1676063693.git.andreyknvl@google.com>
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From: Andrey Konovalov <andreyknvl@google.com>

Group stack depot global variables by their purpose:

1. Hash table-related variables,
2. Slab-related variables,

and add comments.

Also clean up comments for hash table-related constants.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/stackdepot.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 3c713f70b0a3..de1afe3fb24d 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -75,24 +75,31 @@ static bool stack_depot_disabled;
 static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_STACKDEPOT_ALWAYS_INIT);
 static bool __stack_depot_early_init_passed __initdata;
 
-static void *stack_slabs[STACK_ALLOC_MAX_SLABS];
-
-static int depot_index;
-static int next_slab_inited;
-static size_t depot_offset;
-static DEFINE_RAW_SPINLOCK(depot_lock);
-
-/* one hash table bucket entry per 16kB of memory */
+/* Use one hash table bucket per 16 KB of memory. */
 #define STACK_HASH_SCALE	14
-/* limited between 4k and 1M buckets */
+/* Limit the number of buckets between 4K and 1M. */
 #define STACK_HASH_ORDER_MIN	12
 #define STACK_HASH_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;
+/* Hash mask for indexing the table. */
 static unsigned int stack_hash_mask;
 
-static struct stack_record **stack_table;
+/* Array of memory regions that store stack traces. */
+static void *stack_slabs[STACK_ALLOC_MAX_SLABS];
+/* Currently used slab in stack_slabs. */
+static int depot_index;
+/* Offset to the unused space in the currently used slab. */
+static size_t depot_offset;
+/* Lock that protects the variables above. */
+static DEFINE_RAW_SPINLOCK(depot_lock);
+/* Whether the next slab is initialized. */
+static int next_slab_inited;
 
 static int __init disable_stack_depot(char *str)
 {
-- 
2.25.1