On 07.02.23 21:37, Stefan Hajnoczi wrote:
The blk_register_buf() API is an optimization hint that allows some
block drivers to avoid I/O buffer housekeeping or bounce buffers.
Add an -r option to register the I/O buffer so that qemu-io can be used
to test the blk_register_buf() API. The next commit will add a test that
uses the new option.
Reviewed-by: Eric Blake <[email protected]>
Signed-off-by: Stefan Hajnoczi <[email protected]>
---
qemu-io-cmds.c | 204 +++++++++++++++++++++++++++++++------------------
1 file changed, 129 insertions(+), 75 deletions(-)
Reviewed-by: Hanna Czenczek <[email protected]>
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 1f60c23ba4..e7a02f5b99 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -414,24 +419,23 @@ static void *qemu_io_alloc_from_file(BlockBackend *blk,
size_t len,
fclose(f);
f = NULL;
- if (len > pattern_len) {
- len -= pattern_len;
- buf += pattern_len;
-
- while (len > 0) {
- size_t len_to_copy = MIN(pattern_len, len);
-
- memcpy(buf, buf_origin, len_to_copy);
+ if (register_buf) {
+ blk_register_buf(blk, alloc_buf, alloc_len, &error_abort);
+ }
- len -= len_to_copy;
- buf += len_to_copy;
- }
+ end = buf + len;
+ for (char *p = buf + pattern_len; p < end; p += pattern_len) {
+ memcpy(p, buf, MIN(pattern_len, end - p));
}
Cool rewrite of this loop!
