By pulling this function out of mirror_co_read(), the latter becomes simpler. This is important so the following patches can make it more complicated again.
Signed-off-by: Max Reitz <mre...@redhat.com> --- block/mirror.c | 44 ++++++++++++++++++++++++-------------------- 1 file changed, 24 insertions(+), 20 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 6330269156..2a131d8b99 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -293,6 +293,29 @@ static inline void coroutine_fn mirror_co_wait_for_any_operation(s, false); } +/* Allocate a QEMUIOVector from the mirror buffer pool (s->buf_free) */ +static void coroutine_fn mirror_co_alloc_qiov(MirrorBlockJob *s, + QEMUIOVector *qiov, + int64_t offset, uint64_t bytes) +{ + int nb_chunks = DIV_ROUND_UP(bytes, s->granularity); + + while (s->buf_free_count < nb_chunks) { + trace_mirror_yield_in_flight(s, offset, s->in_flight); + mirror_co_wait_for_free_in_flight_slot(s); + } + + qemu_iovec_init(qiov, nb_chunks); + while (nb_chunks-- > 0) { + MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); + size_t remaining = bytes - qiov->size; + + QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); + s->buf_free_count--; + qemu_iovec_add(qiov, buf, MIN(s->granularity, remaining)); + } +} + /* * Restrict *bytes to how much we can actually handle, and align the * [*offset, *bytes] range to clusters if COW is needed. @@ -327,28 +350,9 @@ static void coroutine_fn mirror_co_read(void *opaque) { MirrorOp *op = opaque; MirrorBlockJob *s = op->s; - int nb_chunks; uint64_t ret; - nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity); - - while (s->buf_free_count < nb_chunks) { - trace_mirror_yield_in_flight(s, op->offset, s->in_flight); - mirror_co_wait_for_free_in_flight_slot(s); - } - - /* Now make a QEMUIOVector taking enough granularity-sized chunks - * from s->buf_free. - */ - qemu_iovec_init(&op->qiov, nb_chunks); - while (nb_chunks-- > 0) { - MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); - size_t remaining = op->bytes - op->qiov.size; - - QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); - s->buf_free_count--; - qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining)); - } + mirror_co_alloc_qiov(s, &op->qiov, op->offset, op->bytes); /* Copy the dirty cluster. */ s->in_flight++; -- 2.17.1