We can (and should) rely on the fact that s->flag_compress is exactly one
of DUMP_DH_COMPRESSED_ZLIB, DUMP_DH_COMPRESSED_LZO, and
DUMP_DH_COMPRESSED_SNAPPY.
This is ensured by the QMP schema and dump_init() in combination.
Suggested-by: Paolo Bonzini <pbonz...@redhat.com>
Signed-off-by: Laszlo Ersek <ler...@redhat.com>
---
dump.c | 44 +++++++++++++++-----------------------------
1 file changed, 15 insertions(+), 29 deletions(-)
diff --git a/dump.c b/dump.c
index b87045e..97d2c8d 100644
--- a/dump.c
+++ b/dump.c
@@ -1218,39 +1218,28 @@ static void free_data_cache(DataCache *data_cache)
g_free(data_cache->buf);
}
static size_t get_len_buf_out(size_t page_size, uint32_t flag_compress)
{
- size_t len_buf_out_zlib, len_buf_out_lzo, len_buf_out_snappy;
- size_t len_buf_out;
+ switch (flag_compress) {
+ case DUMP_DH_COMPRESSED_ZLIB:
+ return compressBound(page_size);
- /* init buf_out */
- len_buf_out_zlib = len_buf_out_lzo = len_buf_out_snappy = 0;
-
- /* buf size for zlib */
- len_buf_out_zlib = compressBound(page_size);
-
- /* buf size for lzo */
-#ifdef CONFIG_LZO
- /*
- * LZO will expand incompressible data by a little amount. please check the
- * following URL to see the expansion calculation:
- * http://www.oberhumer.com/opensource/lzo/lzofaq.php
- */
- len_buf_out_lzo = page_size + page_size / 16 + 64 + 3;
-#endif
+ case DUMP_DH_COMPRESSED_LZO:
+ /*
+ * LZO will expand incompressible data by a little amount. Please check
+ * the following URL to see the expansion calculation:
+ * http://www.oberhumer.com/opensource/lzo/lzofaq.php
+ */
+ return page_size + page_size / 16 + 64 + 3;
#ifdef CONFIG_SNAPPY
- /* buf size for snappy */
- len_buf_out_snappy = snappy_max_compressed_length(page_size);
+ case DUMP_DH_COMPRESSED_SNAPPY:
+ return snappy_max_compressed_length(page_size);
#endif
-
- /* get the biggest that can store all kinds of compressed page */
- len_buf_out = MAX(len_buf_out_zlib,
- MAX(len_buf_out_lzo, len_buf_out_snappy));
-
- return len_buf_out;
+ }
+ return 0;
}
/*
* check if the page is all 0
*/
@@ -1282,14 +1271,11 @@ static int write_dump_pages(DumpState *s)
prepare_data_cache(&page_desc, s, offset_desc);
prepare_data_cache(&page_data, s, offset_data);
/* prepare buffer to store compressed data */
len_buf_out = get_len_buf_out(TARGET_PAGE_SIZE, s->flag_compress);
- if (len_buf_out == 0) {
- dump_error(s, "dump: failed to get length of output buffer.\n");
- goto out;
- }
+ assert(len_buf_out != 0);
#ifdef CONFIG_LZO
wrkmem = g_malloc(LZO1X_1_MEM_COMPRESS);
#endif
--
1.8.3.1
