[PATCH v3 08/17] block/io: support int64_t bytes in bdrv_aligned_preadv()

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

We are generally moving to int64_t for both offset and bytes parameters
on all io paths.

Main motivation is realization of 64-bit write_zeroes operation for
fast zeroing large disk chunks, up to the whole disk.

We chose signed type, to be consistent with off_t (which is signed) and
with possibility for signed return type (where negative value means
error).

So, prepare bdrv_aligned_preadv() now.

Make byte variable in bdrv_padding_rmw_read() int64_t, as it defined
only to be passed to bdrv_aligned_preadv().

Series: 64bit-block-status
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/io.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/block/io.c b/block/io.c
index 6990d8cabe..d336e4e691 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1250,16 +1250,17 @@ err:
  * reads; any other features must be implemented by the caller.
  */
 static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
-    BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
+    BdrvTrackedRequest *req, int64_t offset, int64_t bytes,
     int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
 {
     BlockDriverState *bs = child->bs;
     int64_t total_bytes, max_bytes;
     int ret = 0;
-    uint64_t bytes_remaining = bytes;
+    int64_t bytes_remaining = bytes;
     int max_transfer;
 
     assert(is_power_of_2(align));
+    assert(offset >= 0 && bytes >= 0);
     assert((offset & (align - 1)) == 0);
     assert((bytes & (align - 1)) == 0);
     assert((bs->open_flags & BDRV_O_NO_IO) == 0);
@@ -1315,7 +1316,7 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
     }
 
     while (bytes_remaining) {
-        int num;
+        int64_t num;
 
         if (max_bytes) {
             num = MIN(bytes_remaining, MIN(max_bytes, max_transfer));
@@ -1416,7 +1417,7 @@ static int bdrv_padding_rmw_read(BdrvChild *child,
     assert(req->serialising && pad->buf);
 
     if (pad->head || pad->merge_reads) {
-        uint64_t bytes = pad->merge_reads ? pad->buf_len : align;
+        int64_t bytes = pad->merge_reads ? pad->buf_len : align;
 
         qemu_iovec_init_buf(&local_qiov, pad->buf, bytes);
 
-- 
2.21.0