lib/stackdepot: store next pool pointer in new_pool

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.

Link: https://lkml.kernel.org/r/448bc18296c16bef95cb3167697be6583dcc8ce3.1700502145.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>

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index a38661b..68c1ac9 100644 (file)
--- 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;
 
                /*