zswap: allow initialization at boot without pool (ae3d89a7) · Commits · 戴 / test

mm/zswap.c

+34 −12

Original line number	Diff line number	Diff line
		@@ -185,6 +185,9 @@ static bool zswap_init_started;
		/* fatal error during init */
		static bool zswap_init_failed;

		/* init completed, but couldn't create the initial pool */
		static bool zswap_has_pool;

		/*********************************
		* helpers and fwd declarations
		**********************************/
		@@ -424,7 +427,8 @@ static struct zswap_pool *__zswap_pool_current(void)
		struct zswap_pool *pool;

		pool = list_first_or_null_rcu(&zswap_pools, typeof(*pool), list);
		WARN_ON(!pool);
		WARN_ONCE(!pool && zswap_has_pool,
		"%s: no page storage pool!\n", __func__);

		return pool;
		}
		@@ -443,7 +447,7 @@ static struct zswap_pool *zswap_pool_current_get(void)
		rcu_read_lock();

		pool = __zswap_pool_current();
		if (!pool \|\| !zswap_pool_get(pool))
		if (!zswap_pool_get(pool))
		pool = NULL;

		rcu_read_unlock();
		@@ -459,7 +463,9 @@ static struct zswap_pool *zswap_pool_last_get(void)

		list_for_each_entry_rcu(pool, &zswap_pools, list)
		last = pool;
		if (!WARN_ON(!last) && !zswap_pool_get(last))
		WARN_ONCE(!last && zswap_has_pool,
		"%s: no page storage pool!\n", __func__);
		if (!zswap_pool_get(last))
		last = NULL;

		rcu_read_unlock();
		@@ -582,6 +588,9 @@ static void zswap_pool_destroy(struct zswap_pool *pool)

		static int __must_check zswap_pool_get(struct zswap_pool *pool)
		{
		if (!pool)
		return 0;

		return kref_get_unless_zero(&pool->kref);
		}

		@@ -639,7 +648,7 @@ static int __zswap_param_set(const char val, const struct kernel_param kp,
		}

		/* no change required */
		if (!strcmp(s, (char *)kp->arg))
		if (!strcmp(s, (char *)kp->arg) && zswap_has_pool)
		return 0;

		/* if this is load-time (pre-init) param setting,
		@@ -685,6 +694,7 @@ static int __zswap_param_set(const char val, const struct kernel_param kp,
		if (!ret) {
		put_pool = zswap_pool_current();
		list_add_rcu(&pool->list, &zswap_pools);
		zswap_has_pool = true;
		} else if (pool) {
		/* add the possibly pre-existing pool to the end of the pools
		* list; if it's new (and empty) then it'll be removed and
		@@ -692,6 +702,15 @@ static int __zswap_param_set(const char val, const struct kernel_param kp,
		*/
		list_add_tail_rcu(&pool->list, &zswap_pools);
		put_pool = pool;
		} else if (!zswap_has_pool) {
		/* if initial pool creation failed, and this pool creation also
		* failed, maybe both compressor and zpool params were bad.
		* Allow changing this param, so pool creation will succeed
		* when the other param is changed. We already verified this
		* param is ok in the zpool_has_pool() or crypto_has_comp()
		* checks above.
		*/
		ret = param_set_charp(s, kp);
		}

		spin_unlock(&zswap_pools_lock);
		@@ -724,6 +743,10 @@ static int zswap_enabled_param_set(const char *val,
		pr_err("can't enable, initialization failed\n");
		return -ENODEV;
		}
		if (!zswap_has_pool && zswap_init_started) {
		pr_err("can't enable, no pool configured\n");
		return -ENODEV;
		}

		return param_set_bool(val, kp);
		}
		@@ -1205,22 +1228,21 @@ static int __init init_zswap(void)
		goto hp_fail;

		pool = __zswap_pool_create_fallback();
		if (!pool) {
		pr_err("pool creation failed\n");
		goto pool_fail;
		}
		if (pool) {
		pr_info("loaded using pool %s/%s\n", pool->tfm_name,
		zpool_get_type(pool->zpool));

		list_add(&pool->list, &zswap_pools);
		zswap_has_pool = true;
		} else {
		pr_err("pool creation failed\n");
		zswap_enabled = false;
		}

		frontswap_register_ops(&zswap_frontswap_ops);
		if (zswap_debugfs_init())
		pr_warn("debugfs initialization failed\n");
		return 0;

		pool_fail:
		cpuhp_remove_state_nocalls(CPUHP_MM_ZSWP_POOL_PREPARE);
		hp_fail:
		cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE);
		dstmem_fail:

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