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-rw-r--r--mm/zswap.c142
1 files changed, 129 insertions, 13 deletions
diff --git a/mm/zswap.c b/mm/zswap.c
index f9ba9bb1c1b8..4043df7c672f 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -80,23 +80,39 @@ static u64 zswap_duplicate_entry;
static bool zswap_enabled;
module_param_named(enabled, zswap_enabled, bool, 0644);
-/* Compressor to be used by zswap (fixed at boot for now) */
+/* Crypto compressor to use */
#define ZSWAP_COMPRESSOR_DEFAULT "lzo"
-static char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;
-module_param_named(compressor, zswap_compressor, charp, 0444);
-
-/* The maximum percentage of memory that the compressed pool can occupy */
-static unsigned int zswap_max_pool_percent = 20;
-module_param_named(max_pool_percent,
- zswap_max_pool_percent, uint, 0644);
+static char zswap_compressor[CRYPTO_MAX_ALG_NAME] = ZSWAP_COMPRESSOR_DEFAULT;
+static struct kparam_string zswap_compressor_kparam = {
+ .string = zswap_compressor,
+ .maxlen = sizeof(zswap_compressor),
+};
+static int zswap_compressor_param_set(const char *,
+ const struct kernel_param *);
+static struct kernel_param_ops zswap_compressor_param_ops = {
+ .set = zswap_compressor_param_set,
+ .get = param_get_string,
+};
+module_param_cb(compressor, &zswap_compressor_param_ops,
+ &zswap_compressor_kparam, 0644);
-/* Compressed storage to use */
+/* Compressed storage zpool to use */
#define ZSWAP_ZPOOL_DEFAULT "zbud"
-static char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;
-module_param_named(zpool, zswap_zpool_type, charp, 0444);
+static char zswap_zpool_type[32 /* arbitrary */] = ZSWAP_ZPOOL_DEFAULT;
+static struct kparam_string zswap_zpool_kparam = {
+ .string = zswap_zpool_type,
+ .maxlen = sizeof(zswap_zpool_type),
+};
+static int zswap_zpool_param_set(const char *, const struct kernel_param *);
+static struct kernel_param_ops zswap_zpool_param_ops = {
+ .set = zswap_zpool_param_set,
+ .get = param_get_string,
+};
+module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_kparam, 0644);
-/* zpool is shared by all of zswap backend */
-static struct zpool *zswap_pool;
+/* The maximum percentage of memory that the compressed pool can occupy */
+static unsigned int zswap_max_pool_percent = 20;
+module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644);
/*********************************
* data structures
@@ -161,6 +177,9 @@ static LIST_HEAD(zswap_pools);
/* protects zswap_pools list modification */
static DEFINE_SPINLOCK(zswap_pools_lock);
+/* used by param callback function */
+static bool zswap_init_started;
+
/*********************************
* helpers and fwd declarations
**********************************/
@@ -662,6 +681,101 @@ static void zswap_pool_put(struct zswap_pool *pool)
}
/*********************************
+* param callbacks
+**********************************/
+
+static int __zswap_param_set(const char *val, const struct kernel_param *kp,
+ char *type, char *compressor)
+{
+ struct zswap_pool *pool, *put_pool = NULL;
+ char str[kp->str->maxlen], *s;
+ int ret;
+
+ /*
+ * kp is either zswap_zpool_kparam or zswap_compressor_kparam, defined
+ * at the top of this file, so maxlen is CRYPTO_MAX_ALG_NAME (64) or
+ * 32 (arbitrary).
+ */
+ strlcpy(str, val, kp->str->maxlen);
+ s = strim(str);
+
+ /* if this is load-time (pre-init) param setting,
+ * don't create a pool; that's done during init.
+ */
+ if (!zswap_init_started)
+ return param_set_copystring(s, kp);
+
+ /* no change required */
+ if (!strncmp(kp->str->string, s, kp->str->maxlen))
+ return 0;
+
+ if (!type) {
+ type = s;
+ if (!zpool_has_pool(type)) {
+ pr_err("zpool %s not available\n", type);
+ return -ENOENT;
+ }
+ } else if (!compressor) {
+ compressor = s;
+ if (!crypto_has_comp(compressor, 0, 0)) {
+ pr_err("compressor %s not available\n", compressor);
+ return -ENOENT;
+ }
+ }
+
+ spin_lock(&zswap_pools_lock);
+
+ pool = zswap_pool_find_get(type, compressor);
+ if (pool) {
+ zswap_pool_debug("using existing", pool);
+ list_del_rcu(&pool->list);
+ } else {
+ spin_unlock(&zswap_pools_lock);
+ pool = zswap_pool_create(type, compressor);
+ spin_lock(&zswap_pools_lock);
+ }
+
+ if (pool)
+ ret = param_set_copystring(s, kp);
+ else
+ ret = -EINVAL;
+
+ if (!ret) {
+ put_pool = zswap_pool_current();
+ list_add_rcu(&pool->list, &zswap_pools);
+ } 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
+ * destroyed by the put after we drop the lock
+ */
+ list_add_tail_rcu(&pool->list, &zswap_pools);
+ put_pool = pool;
+ }
+
+ spin_unlock(&zswap_pools_lock);
+
+ /* drop the ref from either the old current pool,
+ * or the new pool we failed to add
+ */
+ if (put_pool)
+ zswap_pool_put(put_pool);
+
+ return ret;
+}
+
+static int zswap_compressor_param_set(const char *val,
+ const struct kernel_param *kp)
+{
+ return __zswap_param_set(val, kp, zswap_zpool_type, NULL);
+}
+
+static int zswap_zpool_param_set(const char *val,
+ const struct kernel_param *kp)
+{
+ return __zswap_param_set(val, kp, NULL, zswap_compressor);
+}
+
+/*********************************
* writeback code
**********************************/
/* return enum for zswap_get_swap_cache_page */
@@ -1114,6 +1228,8 @@ static int __init init_zswap(void)
{
struct zswap_pool *pool;
+ zswap_init_started = true;
+
if (zswap_entry_cache_create()) {
pr_err("entry cache creation failed\n");
goto cache_fail;