+ ret = 0;
+fail:
+ qemu_co_mutex_unlock(&s->lock);
+ return ret;
+}
+
+/*
+ * qcow2_compress()
+ *
+ * @dest - destination buffer, at least of @size-1 bytes
+ * @src - source buffer, @size bytes
+ *
+ * Returns: compressed size on success
+ * -1 if compression is inefficient
+ * -2 on any other error
+ */
+static ssize_t qcow2_compress(void *dest, const void *src, size_t size)
+{
+ ssize_t ret;
+ z_stream strm;
+
+ /* best compression, small window, no zlib header */
+ memset(&strm, 0, sizeof(strm));
+ ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, Z_DEFLATED,
+ -12, 9, Z_DEFAULT_STRATEGY);
+ if (ret != 0) {
+ return -2;
+ }
+
+ /* strm.next_in is not const in old zlib versions, such as those used on
+ * OpenBSD/NetBSD, so cast the const away */
+ strm.avail_in = size;
+ strm.next_in = (void *) src;
+ strm.avail_out = size - 1;
+ strm.next_out = dest;
+
+ ret = deflate(&strm, Z_FINISH);
+ if (ret == Z_STREAM_END) {
+ ret = size - 1 - strm.avail_out;
+ } else {
+ ret = (ret == Z_OK ? -1 : -2);
+ }
+
+ deflateEnd(&strm);
+
+ return ret;
+}
+
+#define MAX_COMPRESS_THREADS 4
+
+typedef struct Qcow2CompressData {
+ void *dest;
+ const void *src;
+ size_t size;
+ ssize_t ret;
+} Qcow2CompressData;
+
+static int qcow2_compress_pool_func(void *opaque)
+{
+ Qcow2CompressData *data = opaque;
+
+ data->ret = qcow2_compress(data->dest, data->src, data->size);
+
projects / qemu.git / blobdiff