UBUNTU: Ubuntu-4.10.0-37.41

[mirror_ubuntu-zesty-kernel.git] / mm / zswap.c

diff --git a/mm/zswap.c b/mm/zswap.c
index 067a0d62f31841d16913d36e38531a277ab59b01..cabf09e0128beebdee2b8a959361fe6464fb3469 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"
@@ -176,6 +182,9 @@ 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
 **********************************/
@@ -624,6 +633,11 @@ 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;
@@ -703,6 +717,17 @@ 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
 **********************************/
@@ -1201,6 +1226,9 @@ hp_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 */