qcow2: Use unsigned int for both members of Qcow2COWRegion
Qcow2COWRegion has two attributes:
- The offset of the COW region from the start of the first cluster
touched by the I/O request. Since it's always going to be positive
and the maximum request size is at most INT_MAX, we can use a
regular unsigned int to store this offset.
- The size of the COW region in bytes. This is guaranteed to be >= 0,
so we should use an unsigned type instead.
In x86_64 this reduces the size of Qcow2COWRegion from 16 to 8 bytes.
It will also help keep some assertions simpler now that we know that
there are no negative numbers.
The prototype of do_perform_cow() is also updated to reflect these
changes.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/qcow2.h b/block/qcow2.h
index 1801dc3..c26ee0a 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -301,10 +301,10 @@
* Offset of the COW region in bytes from the start of the first cluster
* touched by the request.
*/
- uint64_t offset;
+ unsigned offset;
/** Number of bytes to copy */
- int nb_bytes;
+ unsigned nb_bytes;
} Qcow2COWRegion;
/**
