scsi: virtio_scsi: implement request batching

Adding the command and kicking the virtqueue so far was done one after
another.  Make the kick optional, so that we can take into account
SCMD_LAST.  We also need a commit_rqs callback to kick the device if
blk-mq aborts the submission before the last request is reached.

Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Paolo Bonzini 2019-05-30 13:28:11 +02:00 • committed by Martin K. Petersen
commit 9e5470fe2d