cifs: fail i/o on soft mounts if sessionsetup errors out

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / mm / zswap.c

diff --git a/mm/zswap.c b/mm/zswap.c
index 025f8dc..87a8491 100644 (file)
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -78,7 +78,13 @@ static u64 zswap_duplicate_entry;
 
 /* Enable/disable zswap (disabled by default) */
 static bool zswap_enabled;
-module_param_named(enabled, zswap_enabled, bool, 0644);
+static int zswap_enabled_param_set(const char *,
+                                  const struct kernel_param *);
+static struct kernel_param_ops zswap_enabled_param_ops = {
+       .set =          zswap_enabled_param_set,
+       .get =          param_get_bool,
+};
+module_param_cb(enabled, &zswap_enabled_param_ops, &zswap_enabled, 0644);
 
 /* Crypto compressor to use */
 #define ZSWAP_COMPRESSOR_DEFAULT "lzo"
@@ -117,7 +123,7 @@ struct zswap_pool {
        struct crypto_comp * __percpu *tfm;
        struct kref kref;
        struct list_head list;
-       struct rcu_head rcu_head;
+       struct work_struct work;
        struct notifier_block notifier;
        char tfm_name[CRYPTO_MAX_ALG_NAME];
 };
@@ -170,10 +176,15 @@ static struct zswap_tree *zswap_trees[MAX_SWAPFILES];
 static LIST_HEAD(zswap_pools);
 /* protects zswap_pools list modification */
 static DEFINE_SPINLOCK(zswap_pools_lock);
+/* pool counter to provide unique names to zpool */
+static atomic_t zswap_pools_count = ATOMIC_INIT(0);
 
 /* used by param callback function */
 static bool zswap_init_started;
 
+/* fatal error during init */
+static bool zswap_init_failed;
+
 /*********************************
 * helpers and fwd declarations
 **********************************/
@@ -541,6 +552,7 @@ static struct zswap_pool *zswap_pool_last_get(void)
        return last;
 }
 
+/* type and compressor must be null-terminated */
 static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
 {
        struct zswap_pool *pool;
@@ -548,10 +560,9 @@ static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
        assert_spin_locked(&zswap_pools_lock);
 
        list_for_each_entry_rcu(pool, &zswap_pools, list) {
-               if (strncmp(pool->tfm_name, compressor, sizeof(pool->tfm_name)))
+               if (strcmp(pool->tfm_name, compressor))
                        continue;
-               if (strncmp(zpool_get_type(pool->zpool), type,
-                           sizeof(zswap_zpool_type)))
+               if (strcmp(zpool_get_type(pool->zpool), type))
                        continue;
                /* if we can't get it, it's about to be destroyed */
                if (!zswap_pool_get(pool))
@@ -565,6 +576,7 @@ static struct zswap_pool *zswap_pool_find_get(char *type, char *compressor)
 static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
 {
        struct zswap_pool *pool;
+       char name[38]; /* 'zswap' + 32 char (max) num + \0 */
        gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM;
 
        pool = kzalloc(sizeof(*pool), GFP_KERNEL);
@@ -573,7 +585,10 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor)
                return NULL;
        }
 
-       pool->zpool = zpool_create_pool(type, "zswap", gfp, &zswap_zpool_ops);
+       /* unique name for each pool specifically required by zsmalloc */
+       snprintf(name, 38, "zswap%x", atomic_inc_return(&zswap_pools_count));
+
+       pool->zpool = zpool_create_pool(type, name, gfp, &zswap_zpool_ops);
        if (!pool->zpool) {
                pr_err("%s zpool not available\n", type);
                goto error;
@@ -652,9 +667,11 @@ static int __must_check zswap_pool_get(struct zswap_pool *pool)
        return kref_get_unless_zero(&pool->kref);
 }
 
-static void __zswap_pool_release(struct rcu_head *head)
+static void __zswap_pool_release(struct work_struct *work)
 {
-       struct zswap_pool *pool = container_of(head, typeof(*pool), rcu_head);
+       struct zswap_pool *pool = container_of(work, typeof(*pool), work);
+
+       synchronize_rcu();
 
        /* nobody should have been able to get a kref... */
        WARN_ON(kref_get_unless_zero(&pool->kref));
@@ -674,7 +691,9 @@ static void __zswap_pool_empty(struct kref *kref)
        WARN_ON(pool == zswap_pool_current());
 
        list_del_rcu(&pool->list);
-       call_rcu(&pool->rcu_head, __zswap_pool_release);
+
+       INIT_WORK(&pool->work, __zswap_pool_release);
+       schedule_work(&pool->work);
 
        spin_unlock(&zswap_pools_lock);
 }
@@ -696,6 +715,11 @@ static int __zswap_param_set(const char *val, const struct kernel_param *kp,
        char *s = strstrip((char *)val);
        int ret;
 
+       if (zswap_init_failed) {
+               pr_err("can't set param, initialization failed\n");
+               return -ENODEV;
+       }
+
        /* no change required */
        if (!strcmp(s, *(char **)kp->arg))
                return 0;
@@ -728,18 +752,22 @@ static int __zswap_param_set(const char *val, const struct kernel_param *kp,
        pool = zswap_pool_find_get(type, compressor);
        if (pool) {
                zswap_pool_debug("using existing", pool);
+               WARN_ON(pool == zswap_pool_current());
                list_del_rcu(&pool->list);
-       } else {
-               spin_unlock(&zswap_pools_lock);
-               pool = zswap_pool_create(type, compressor);
-               spin_lock(&zswap_pools_lock);
        }
 
+       spin_unlock(&zswap_pools_lock);
+
+       if (!pool)
+               pool = zswap_pool_create(type, compressor);
+
        if (pool)
                ret = param_set_charp(s, kp);
        else
                ret = -EINVAL;
 
+       spin_lock(&zswap_pools_lock);
+
        if (!ret) {
                put_pool = zswap_pool_current();
                list_add_rcu(&pool->list, &zswap_pools);
@@ -775,6 +803,17 @@ static int zswap_zpool_param_set(const char *val,
        return __zswap_param_set(val, kp, NULL, zswap_compressor);
 }
 
+static int zswap_enabled_param_set(const char *val,
+                                  const struct kernel_param *kp)
+{
+       if (zswap_init_failed) {
+               pr_err("can't enable, initialization failed\n");
+               return -ENODEV;
+       }
+
+       return param_set_bool(val, kp);
+}
+
 /*********************************
 * writeback code
 **********************************/
@@ -979,6 +1018,15 @@ static int zswap_frontswap_store(unsigned type, pgoff_t offset,
                        ret = -ENOMEM;
                        goto reject;
                }
+
+               /* A second zswap_is_full() check after
+                * zswap_shrink() to make sure it's now
+                * under the max_pool_percent
+                */
+               if (zswap_is_full()) {
+                       ret = -ENOMEM;
+                       goto reject;
+               }
        }
 
        /* allocate entry */
@@ -1261,6 +1309,9 @@ pool_fail:
 dstmem_fail:
        zswap_entry_cache_destroy();
 cache_fail:
+       /* if built-in, we aren't unloaded on failure; don't allow use */
+       zswap_init_failed = true;
+       zswap_enabled = false;
        return -ENOMEM;
 }
 /* must be late so crypto has time to come up */