consolidate qemu_iovec_copy() and qemu_iovec_concat() and make them consistent

qemu_iovec_concat() is currently a wrapper for
qemu_iovec_copy(), use the former (with extra
"0" arg) in a few places where it is used.

Change skip argument of qemu_iovec_copy() from
uint64_t to size_t, since size of qiov itself
is size_t, so there's no way to skip larger
sizes.  Rename it to soffset, to make it clear
that the offset is applied to src.

Also change the only usage of uint64_t in
hw/9pfs/virtio-9p.c, in v9fs_init_qiov_from_pdu() -
all callers of it actually uses size_t too,
not uint64_t.

One added restriction: as for all other iovec-related
functions, soffset must point inside src.

Order of argumens is already good:
 qemu_iovec_memset(QEMUIOVector *qiov, size_t offset,
                   int c, size_t bytes)
vs:
 qemu_iovec_concat(QEMUIOVector *dst,
                   QEMUIOVector *src,
                   size_t soffset, size_t sbytes)
(note soffset is after _src_ not dst, since it applies to src;
for memset it applies to qiov).

Note that in many places where this function is used,
the previous call is qemu_iovec_reset(), which means
many callers actually want copy (replacing dst content),
not concat.  So we may want to add a wrapper like
qemu_iovec_copy() with the same arguments but which
calls qemu_iovec_reset() before _concat().

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

1 files changed, 3 insertions, 3 deletions

diff --git a/block/qed.c b/block/qed.c
index 40bdb5364a..847417a3d6 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -1131,7 +1131,7 @@ static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len)
 
     acb->cur_nclusters = qed_bytes_to_clusters(s,
             qed_offset_into_cluster(s, acb->cur_pos) + len);
-    qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
+    qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
 
     if (acb->flags & QED_AIOCB_ZERO) {
         /* Skip ahead if the clusters are already zero */
@@ -1177,7 +1177,7 @@ static void qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len)
 
     /* Calculate the I/O vector */
     acb->cur_cluster = offset;
-    qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
+    qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
 
     /* Do the actual write */
     qed_aio_write_main(acb, 0);
@@ -1247,7 +1247,7 @@ static void qed_aio_read_data(void *opaque, int ret,
         goto err;
     }
 
-    qemu_iovec_copy(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
+    qemu_iovec_concat(&acb->cur_qiov, acb->qiov, acb->qiov_offset, len);
 
     /* Handle zero cluster and backing file reads */
     if (ret == QED_CLUSTER_ZERO) {