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().
All bdrv_aligned_preadv() callers are safe as type is widening. Let's
look inside:
- add a new-style assertion that request is good.
- callees bdrv_is_allocated(), bdrv_co_do_copy_on_readv() supports
int64_t bytes
- conversion of bytes_remaining is OK, as we never has requests
overflowing BDRV_MAX_LENGTH
- looping through bytes_remaining is ok, num is updated to int64_t
- for bdrv_driver_preadv we have same limit of max_transfer
- qemu_iovec_memset is OK, as bytes+qiov_offset should not overflow
qiov->size anyway (thanks to bdrv_check_qiov_request())
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---
block/io.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/block/io.c b/block/io.c
index d8c07fac56..93a89a56e3 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1453,15 +1453,16 @@ 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;
+ bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort);
assert(is_power_of_2(align));
assert((offset & (align - 1)) == 0);
assert((bytes & (align - 1)) == 0);
@@ -1518,7 +1519,7 @@ 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));
@@ -1624,7 +1625,7 @@ 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);
--
2.25.4
