1 files changed, 115 insertions, 0 deletions
diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
new file mode 100644
index 0000000..22f4ae2
--- /dev/null
+++ b/drivers/block/zram/zcomp.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2014 Sergey Senozhatsky.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+
+#include "zcomp.h"
+#include "zcomp_lzo.h"
+
+static struct zcomp_backend *find_backend(const char *compress)
+{
+	if (strncmp(compress, "lzo", 3) == 0)
+		return &zcomp_lzo;
+	return NULL;
+}
+
+static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+	if (zstrm->private)
+		comp->backend->destroy(zstrm->private);
+	free_pages((unsigned long)zstrm->buffer, 1);
+	kfree(zstrm);
+}
+
+/*
+ * allocate new zcomp_strm structure with ->private initialized by
+ * backend, return NULL on error
+ */
+static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
+{
+	struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL);
+	if (!zstrm)
+		return NULL;
+
+	zstrm->private = comp->backend->create();
+	/*
+	 * 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(GFP_KERNEL | __GFP_ZERO, 1);
+	if (!zstrm->private || !zstrm->buffer) {
+		zcomp_strm_free(comp, zstrm);
+		zstrm = NULL;
+	}
+	return zstrm;
+}
+
+struct zcomp_strm *zcomp_strm_find(struct zcomp *comp)
+{
+	mutex_lock(&comp->strm_lock);
+	return comp->zstrm;
+}
+
+void zcomp_strm_release(struct zcomp *comp, struct zcomp_strm *zstrm)
+{
+	mutex_unlock(&comp->strm_lock);
+}
+
+int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
+		const unsigned char *src, size_t *dst_len)
+{
+	return comp->backend->compress(src, zstrm->buffer, dst_len,
+			zstrm->private);
+}
+
+int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
+		size_t src_len, unsigned char *dst)
+{
+	return comp->backend->decompress(src, src_len, dst);
+}
+
+void zcomp_destroy(struct zcomp *comp)
+{
+	zcomp_strm_free(comp, comp->zstrm);
+	kfree(comp);
+}
+
+/*
+ * search available compressors for requested algorithm.
+ * allocate new zcomp and initialize it. return NULL
+ * if requested algorithm is not supported or in case
+ * of init error
+ */
+struct zcomp *zcomp_create(const char *compress)
+{
+	struct zcomp *comp;
+	struct zcomp_backend *backend;
+
+	backend = find_backend(compress);
+	if (!backend)
+		return NULL;
+
+	comp = kzalloc(sizeof(struct zcomp), GFP_KERNEL);
+	if (!comp)
+		return NULL;
+
+	comp->backend = backend;
+	mutex_init(&comp->strm_lock);
+
+	comp->zstrm = zcomp_strm_alloc(comp);
+	if (!comp->zstrm) {
+		kfree(comp);
+		return NULL;
+	}
+	return comp;
+}