CLEANUP: pools: do not use the extra pointer to link shared elements
This practice relying on POOL_LINK() dates from the era where there were
no pool caches, but given that the structures are a bit more complex now
and that pool caches do not make use of this feature, it is totally
useless since released elements have already been overwritten, and yet
it complicates the architecture and prevents from making simplifications
and optimizations. Let's just get rid of this feature. The pointer to
the origin pool is preserved though, as it helps detect incorrect frees
and serves as a canary for overflows.
diff --git a/include/haproxy/pool-t.h b/include/haproxy/pool-t.h
index 48d06be..d476f31 100644
--- a/include/haproxy/pool-t.h
+++ b/include/haproxy/pool-t.h
@@ -40,7 +40,6 @@
#define POOL_LINK(pool, item) (void **)(((char *)(item)) + ((pool)->size))
#else
#define POOL_EXTRA (0)
-#define POOL_LINK(pool, item) ((void **)(item))
#endif
/* A special pointer for the pool's free_list that indicates someone is
diff --git a/include/haproxy/pool.h b/include/haproxy/pool.h
index cb2c8b4..d8407b1 100644
--- a/include/haproxy/pool.h
+++ b/include/haproxy/pool.h
@@ -132,7 +132,7 @@
}
/* this releases the lock */
- _HA_ATOMIC_STORE(&pool->free_list, *POOL_LINK(pool, ret));
+ _HA_ATOMIC_STORE(&pool->free_list, *(void **)ret);
_HA_ATOMIC_INC(&pool->used);
#ifdef DEBUG_MEMORY_POOLS
@@ -164,7 +164,7 @@
__ha_cpu_relax();
free_list = _HA_ATOMIC_LOAD(&pool->free_list);
}
- _HA_ATOMIC_STORE(POOL_LINK(pool, ptr), (void *)free_list);
+ _HA_ATOMIC_STORE((void **)ptr, (void *)free_list);
__ha_barrier_atomic_store();
} while (!_HA_ATOMIC_CAS(&pool->free_list, &free_list, ptr));
__ha_barrier_atomic_store();
diff --git a/src/pool.c b/src/pool.c
index e64bfca..7d83a95 100644
--- a/src/pool.c
+++ b/src/pool.c
@@ -417,7 +417,7 @@
while (next) {
temp = next;
- next = *POOL_LINK(pool, temp);
+ next = *(void **)temp;
pool_put_to_os(pool, temp);
}
/* here, we should have pool->allocated == pool->used */
@@ -442,7 +442,7 @@
while (entry->free_list &&
(int)(entry->allocated - entry->used) > (int)entry->minavail) {
temp = entry->free_list;
- entry->free_list = *POOL_LINK(entry, temp);
+ entry->free_list = *(void **)temp;
pool_put_to_os(entry, temp);
}
}