qcow2: Use unsigned int for both members of Qcow2COWRegion
commite034f5bcbc1139903b27c00bd832ee7c4b065810
authorAlberto Garcia <berto@igalia.com>
Mon, 19 Jun 2017 13:40:03 +0000 (19 16:40 +0300)
committerKevin Wolf <kwolf@redhat.com>
Mon, 26 Jun 2017 12:51:13 +0000 (26 14:51 +0200)
tree43ed75d6da2b0cc4fdae06fd749cea7a5a57b7ca
parent026ac1586bdbd184e24082aa2bbab1fa3c48456b
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>
block/qcow2-cluster.c
block/qcow2.h