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From:   andrey.konovalov@linux.dev
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Andrey Konovalov <andreyknvl@gmail.com>,
        Marco Elver <elver@google.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vlastimil Babka <vbabka@suse.cz>, kasan-dev@googlegroups.com,
        Evgenii Stepanov <eugenis@google.com>,
        Oscar Salvador <osalvador@suse.de>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v4 10/22] lib/stackdepot: store next pool pointer in new_pool
Date:   Mon, 20 Nov 2023 18:47:08 +0100
Message-Id: <448bc18296c16bef95cb3167697be6583dcc8ce3.1700502145.git.andreyknvl@google.com>
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From: Andrey Konovalov <andreyknvl@google.com>

Instead of using the last pointer in stack_pools for storing the pointer
to a new pool (which does not yet store any stack records), use a new
new_pool variable.

This a purely code readability change: it seems more logical to store
the pointer to a pool with a special meaning in a dedicated variable.

Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/stackdepot.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index a38661beab97..68c1ac9aa916 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -85,6 +85,8 @@ static unsigned int stack_hash_mask;
 
 /* Array of memory regions that store stack traces. */
 static void *stack_pools[DEPOT_MAX_POOLS];
+/* Newly allocated pool that is not yet added to stack_pools. */
+static void *new_pool;
 /* Currently used pool in stack_pools. */
 static int pool_index;
 /* Offset to the unused space in the currently used pool. */
@@ -241,7 +243,7 @@ static void depot_keep_new_pool(void **prealloc)
 	 * as long as we do not exceed the maximum number of pools.
 	 */
 	if (pool_index + 1 < DEPOT_MAX_POOLS) {
-		stack_pools[pool_index + 1] = *prealloc;
+		new_pool = *prealloc;
 		*prealloc = NULL;
 	}
 
@@ -272,6 +274,8 @@ static bool depot_update_pools(size_t required_size, void **prealloc)
 		 * stack_depot_fetch().
 		 */
 		WRITE_ONCE(pool_index, pool_index + 1);
+		stack_pools[pool_index] = new_pool;
+		new_pool = NULL;
 		pool_offset = 0;
 
 		/*
-- 
2.25.1