Commit c99b42c3 authored by Dan Streetman's avatar Dan Streetman Committed by Linus Torvalds
Browse files

zswap: use charp for zswap param strings 



Instead of using a fixed-length string for the zswap params, use charp.
This simplifies the code and uses less memory, as most zswap param strings
will be less than the current maximum length.

Signed-off-by: default avatarDan Streetman <ddstreet@ieee.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Seth Jennings <sjennings@variantweb.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3d9c637f

mm/zswap.c

+40 −40
Original line number Diff line number Diff line
@@ -82,33 +82,27 @@ module_param_named(enabled, zswap_enabled, bool, 0644); 


/* Crypto compressor to use */

#define ZSWAP_COMPRESSOR_DEFAULT "lzo"

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 char *zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;

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,

	.get =		param_get_charp,

	.free =		param_free_charp,

};

module_param_cb(compressor, &zswap_compressor_param_ops,

		&zswap_compressor_kparam, 0644);

		&zswap_compressor, 0644);



/* Compressed storage zpool to use */

#define ZSWAP_ZPOOL_DEFAULT "zbud"

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 char *zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;

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,

	.get =		param_get_charp,

	.free =		param_free_charp,

};

module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_kparam, 0644);

module_param_cb(zpool, &zswap_zpool_param_ops, &zswap_zpool_type, 0644);



/* The maximum percentage of memory that the compressed pool can occupy */

static unsigned int zswap_max_pool_percent = 20;
@@ -615,19 +609,29 @@ error: 
	return NULL;

}



static struct zswap_pool *__zswap_pool_create_fallback(void)

static __init struct zswap_pool *__zswap_pool_create_fallback(void)

{

	if (!crypto_has_comp(zswap_compressor, 0, 0)) {

		if (!strcmp(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT)) {

			pr_err("default compressor %s not available\n",

			       zswap_compressor);

			return NULL;

		}

		pr_err("compressor %s not available, using default %s\n",

		       zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT);

		strncpy(zswap_compressor, ZSWAP_COMPRESSOR_DEFAULT,

			sizeof(zswap_compressor));

		param_free_charp(&zswap_compressor);

		zswap_compressor = ZSWAP_COMPRESSOR_DEFAULT;

	}

	if (!zpool_has_pool(zswap_zpool_type)) {

		if (!strcmp(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT)) {

			pr_err("default zpool %s not available\n",

			       zswap_zpool_type);

			return NULL;

		}

		pr_err("zpool %s not available, using default %s\n",

		       zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT);

		strncpy(zswap_zpool_type, ZSWAP_ZPOOL_DEFAULT,

			sizeof(zswap_zpool_type));

		param_free_charp(&zswap_zpool_type);

		zswap_zpool_type = ZSWAP_ZPOOL_DEFAULT;

	}



	return zswap_pool_create(zswap_zpool_type, zswap_compressor);
@@ -684,43 +688,39 @@ static void zswap_pool_put(struct zswap_pool *pool) 
* param callbacks

**********************************/



/* val must be a null-terminated string */

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;

	char *s = strstrip((char *)val);

	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);

	/* no change required */

	if (!strcmp(s, *(char **)kp->arg))

		return 0;



	/* 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;

		return param_set_charp(s, kp);



	if (!type) {

		type = s;

		if (!zpool_has_pool(type)) {

			pr_err("zpool %s not available\n", type);

		if (!zpool_has_pool(s)) {

			pr_err("zpool %s not available\n", s);

			return -ENOENT;

		}

		type = s;

	} else if (!compressor) {

		compressor = s;

		if (!crypto_has_comp(compressor, 0, 0)) {

			pr_err("compressor %s not available\n", compressor);

		if (!crypto_has_comp(s, 0, 0)) {

			pr_err("compressor %s not available\n", s);

			return -ENOENT;

		}

		compressor = s;

	} else {

		WARN_ON(1);

		return -EINVAL;

	}



	spin_lock(&zswap_pools_lock);
@@ -736,7 +736,7 @@ static int __zswap_param_set(const char *val, const struct kernel_param *kp, 
	}



	if (pool)

		ret = param_set_copystring(s, kp);

		ret = param_set_charp(s, kp);

	else

		ret = -EINVAL;

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