Follow-up to the pread/pwrite_all API series [1].

qemu_put_buffer_at(), qemu_get_buffer_at(), and file_write_ramblock_iov()
all use single-shot positioned I/O without retry.  They share the same
pattern as the bug fixed in multifd_file_recv_data() where a short
transfer would be mishandled.

Convert them to the _all helpers and clean up a pre-existing
const-correctness issue in qemu_get_buffer_at() along the way.

After this series no positioned I/O call site in migration/ uses raw
single-shot channel operations.

Depends-on: <20260413214549.926435-1-junjie.cao@intel.com>
("io/channel: complete pread/pwrite_all API and fix
multifd_file_recv_data")

[1] https://lore.kernel.org/qemu-devel/20260413214549.926435-1-junjie.cao@intel.com/

Junjie Cao (3):
  migration/qemu-file: switch buffer_at functions to positioned I/O _all
    helpers
  migration/file: switch file_write_ramblock_iov to pwritev_all
  migration/qemu-file: drop incorrect const from qemu_get_buffer_at buf

 migration/file.c      |  8 ++++----
 migration/qemu-file.c | 37 ++++---------------------------------
 migration/qemu-file.h |  2 +-
 3 files changed, 9 insertions(+), 38 deletions(-)

-- 
2.43.0