1 files changed, 95 insertions, 55 deletions

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index b51a816d7..4b5cd3a7b 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -14,108 +14,150 @@
 #include <linux/wait.h>
 #include <linux/sched.h>
 #include <linux/cpu.h>
+#include <linux/crypto.h>
 
 #include "zcomp.h"
-#include "zcomp_lzo.h"
-#ifdef CONFIG_ZRAM_LZ4_COMPRESS
-#include "zcomp_lz4.h"
-#endif
 
-static struct zcomp_backend *backends[] = {
-	&zcomp_lzo,
-#ifdef CONFIG_ZRAM_LZ4_COMPRESS
-	&zcomp_lz4,
+static const char * const backends[] = {
+	"lzo",
+#if IS_ENABLED(CONFIG_CRYPTO_LZ4)
+	"lz4",
+#endif
+#if IS_ENABLED(CONFIG_CRYPTO_DEFLATE)
+	"deflate",
+#endif
+#if IS_ENABLED(CONFIG_CRYPTO_LZ4HC)
+	"lz4hc",
+#endif
+#if IS_ENABLED(CONFIG_CRYPTO_842)
+	"842",
 #endif
 	NULL
 };
 
-static struct zcomp_backend *find_backend(const char *compress)
-{
-	int i = 0;
-	while (backends[i]) {
-		if (sysfs_streq(compress, backends[i]->name))
-			break;
-		i++;
-	}
-	return backends[i];
-}
-
-static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
+static void zcomp_strm_free(struct zcomp_strm *zstrm)
 {
-	if (zstrm->private)
-		comp->backend->destroy(zstrm->private);
+	if (!IS_ERR_OR_NULL(zstrm->tfm))
+		crypto_free_comp(zstrm->tfm);
 	free_pages((unsigned long)zstrm->buffer, 1);
 	kfree(zstrm);
 }
 
 /*
- * allocate new zcomp_strm structure with ->private initialized by
+ * allocate new zcomp_strm structure with ->tfm initialized by
  * backend, return NULL on error
  */
-static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp, gfp_t flags)
+static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
 {
-	struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), flags);
+	struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL);
 	if (!zstrm)
 		return NULL;
 
-	zstrm->private = comp->backend->create(flags);
+	zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0);
 	/*
 	 * allocate 2 pages. 1 for compressed data, plus 1 extra for the
 	 * case when compressed size is larger than the original one
 	 */
-	zstrm->buffer = (void *)__get_free_pages(flags | __GFP_ZERO, 1);
-	if (!zstrm->private || !zstrm->buffer) {
-		zcomp_strm_free(comp, zstrm);
+	zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
+	if (IS_ERR_OR_NULL(zstrm->tfm) || !zstrm->buffer) {
+		zcomp_strm_free(zstrm);
 		zstrm = NULL;
 	}
 	return zstrm;
 }
 
+bool zcomp_available_algorithm(const char *comp)
+{
+	int i = 0;
+
+	while (backends[i]) {
+		if (sysfs_streq(comp, backends[i]))
+			return true;
+		i++;
+	}
+
+	/*
+	 * Crypto does not ignore a trailing new line symbol,
+	 * so make sure you don't supply a string containing
+	 * one.
+	 * This also means that we permit zcomp initialisation
+	 * with any compressing algorithm known to crypto api.
+	 */
+	return crypto_has_comp(comp, 0, 0) == 1;
+}
+
 /* show available compressors */
 ssize_t zcomp_available_show(const char *comp, char *buf)
 {
+	bool known_algorithm = false;
 	ssize_t sz = 0;
 	int i = 0;
 
-	while (backends[i]) {
-		if (!strcmp(comp, backends[i]->name))
+	for (; backends[i]; i++) {
+		if (!strcmp(comp, backends[i])) {
+			known_algorithm = true;
 			sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
-					"[%s] ", backends[i]->name);
-		else
+					"[%s] ", backends[i]);
+		} else {
 			sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
-					"%s ", backends[i]->name);
-		i++;
+					"%s ", backends[i]);
+		}
 	}
+
+	/*
+	 * Out-of-tree module known to crypto api or a missing
+	 * entry in `backends'.
+	 */
+	if (!known_algorithm && crypto_has_comp(comp, 0, 0) == 1)
+		sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
+				"[%s] ", comp);
+
 	sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
 	return sz;
 }
 
-bool zcomp_available_algorithm(const char *comp)
-{
-	return find_backend(comp) != NULL;
-}
-
-struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
+struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
 {
 	return *get_cpu_ptr(comp->stream);
 }
 
-void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm)
+void zcomp_stream_put(struct zcomp *comp)
 {
 	put_cpu_ptr(comp->stream);
 }
 
-int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
-		const unsigned char *src, size_t *dst_len)
+int zcomp_compress(struct zcomp_strm *zstrm,
+		const void *src, unsigned int *dst_len)
 {
-	return comp->backend->compress(src, zstrm->buffer, dst_len,
-			zstrm->private);
+	/*
+	 * Our dst memory (zstrm->buffer) is always `2 * PAGE_SIZE' sized
+	 * because sometimes we can endup having a bigger compressed data
+	 * due to various reasons: for example compression algorithms tend
+	 * to add some padding to the compressed buffer. Speaking of padding,
+	 * comp algorithm `842' pads the compressed length to multiple of 8
+	 * and returns -ENOSP when the dst memory is not big enough, which
+	 * is not something that ZRAM wants to see. We can handle the
+	 * `compressed_size > PAGE_SIZE' case easily in ZRAM, but when we
+	 * receive -ERRNO from the compressing backend we can't help it
+	 * anymore. To make `842' happy we need to tell the exact size of
+	 * the dst buffer, zram_drv will take care of the fact that
+	 * compressed buffer is too big.
+	 */
+	*dst_len = PAGE_SIZE * 2;
+
+	return crypto_comp_compress(zstrm->tfm,
+			src, PAGE_SIZE,
+			zstrm->buffer, dst_len);
 }
 
-int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
-		size_t src_len, unsigned char *dst)
+int zcomp_decompress(struct zcomp_strm *zstrm,
+		const void *src, unsigned int src_len, void *dst)
 {
-	return comp->backend->decompress(src, src_len, dst);
+	unsigned int dst_len = PAGE_SIZE;
+
+	return crypto_comp_decompress(zstrm->tfm,
+			src, src_len,
+			dst, &dst_len);
 }
 
 static int __zcomp_cpu_notifier(struct zcomp *comp,
@@ -127,7 +169,7 @@ static int __zcomp_cpu_notifier(struct zcomp *comp,
 	case CPU_UP_PREPARE:
 		if (WARN_ON(*per_cpu_ptr(comp->stream, cpu)))
 			break;
-		zstrm = zcomp_strm_alloc(comp, GFP_KERNEL);
+		zstrm = zcomp_strm_alloc(comp);
 		if (IS_ERR_OR_NULL(zstrm)) {
 			pr_err("Can't allocate a compression stream\n");
 			return NOTIFY_BAD;
@@ -138,7 +180,7 @@ static int __zcomp_cpu_notifier(struct zcomp *comp,
 	case CPU_UP_CANCELED:
 		zstrm = *per_cpu_ptr(comp->stream, cpu);
 		if (!IS_ERR_OR_NULL(zstrm))
-			zcomp_strm_free(comp, zstrm);
+			zcomp_strm_free(zstrm);
 		*per_cpu_ptr(comp->stream, cpu) = NULL;
 		break;
 	default:
@@ -209,18 +251,16 @@ void zcomp_destroy(struct zcomp *comp)
 struct zcomp *zcomp_create(const char *compress)
 {
 	struct zcomp *comp;
-	struct zcomp_backend *backend;
 	int error;
 
-	backend = find_backend(compress);
-	if (!backend)
+	if (!zcomp_available_algorithm(compress))
 		return ERR_PTR(-EINVAL);
 
 	comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
 	if (!comp)
 		return ERR_PTR(-ENOMEM);
 
-	comp->backend = backend;
+	comp->name = compress;
 	error = zcomp_init(comp);
 	if (error) {
 		kfree(comp);