X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=mm%2Fzswap.c;h=45476f429789f5d578221e3c232ab216b3772534;hb=0f1294525b11a9cb4115bef712cf70fce93b315f;hp=340261946fda6a18845c1c9fae378ade8c2abb61;hpb=2ea80ad4205178dcea1152c0a603f23531c5412c;p=firefly-linux-kernel-4.4.55.git

diff --git a/mm/zswap.c b/mm/zswap.c
index 340261946fda..45476f429789 100644
--- 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
 **********************************/
@@ -702,6 +711,11 @@ 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;
@@ -781,6 +795,17 @@ 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
 **********************************/
@@ -1267,6 +1292,9 @@ 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 */