On Fri, Feb 02, 2024 at 05:39:32PM +0800, Xuan Zhuo wrote:

As discussed:
http://lore.kernel.org/all/CACGkMEvq0No8QGC46U4mGsMtuD44fD_cfLcPaVmJ3rHYqRZxYg@mail.gmail.com (local)

If the virtio is premapped mode, the driver should manage the dma info by self.
So the virtio core should not store the dma info.
So we can release the memory used to store the dma info.

But if the desc_extra has not dma info, we face a new question,
it is hard to get the dma info of the desc with indirect flag.
For split mode, that is easy from desc, but for the packed mode,
it is hard to get the dma info from the desc. And for hardening
the dma unmap is saft, we should store the dma info of indirect
descs.

So I introduce the "structure the indirect desc table" to
allocate space to store dma info with the desc table.

On the other side, we mix the descs with indirect flag
with other descs together to share the unmap api. That
is complex. I found if we we distinguish the descs with
VRING_DESC_F_INDIRECT before unmap, thing will be clearer.

Because of the dma array is allocated in the find_vqs(),
so I introduce a new parameter to find_vqs().

Please review.

Thanks

this needs a rebase - conflicts with e.g.
commit e3fe8d28c67bf6c291e920c6d04fa22afa14e6e4
Author: Zhu Yanjun [off-list ref]
Date:   Thu Jan 4 10:09:02 2024 +0800

    virtio_net: Fix "‘%d’ directive writing between 1 and 11 bytes into a region of size 10" warnings
    
    Fix the warnings when building virtio_net driver.
    

thanks!

v1:
    1. rename transport_vq_config to vq_transport_config
    2. virtio-net set dma meta number to (ring-size + 1)(MAX_SKB_FRGAS +2)
    3. introduce virtqueue_dma_map_sg_attrs
    4. separate vring_create_virtqueue to an independent commit

Xuan Zhuo (19):
  virtio_ring: introduce vring_need_unmap_buffer
  virtio_ring: packed: remove double check of the unmap ops
  virtio_ring: packed: structure the indirect desc table
  virtio_ring: split: remove double check of the unmap ops
  virtio_ring: split: structure the indirect desc table
  virtio_ring: no store dma info when unmap is not needed
  virtio: find_vqs: pass struct instead of multi parameters
  virtio: vring_create_virtqueue: pass struct instead of multi
    parameters
  virtio: vring_new_virtqueue(): pass struct instead of multi parameters
  virtio_ring: reuse the parameter struct of find_vqs()
  virtio: find_vqs: add new parameter premapped
  virtio_ring: export premapped to driver by struct virtqueue
  virtio_net: set premapped mode by find_vqs()
  virtio_ring: remove api of setting vq premapped
  virtio_ring: introduce dma map api for page
  virtio_ring: introduce virtqueue_dma_map_sg_attrs
  virtio_net: unify the code for recycling the xmit ptr
  virtio_net: rename free_old_xmit_skbs to free_old_xmit
  virtio_net: sq support premapped mode

 arch/um/drivers/virtio_uml.c             |  31 +-
 drivers/net/virtio_net.c                 | 291 +++++++---
 drivers/platform/mellanox/mlxbf-tmfifo.c |  24 +-
 drivers/remoteproc/remoteproc_virtio.c   |  31 +-
 drivers/s390/virtio/virtio_ccw.c         |  33 +-
 drivers/virtio/virtio_mmio.c             |  30 +-
 drivers/virtio/virtio_pci_common.c       |  59 +-
 drivers/virtio/virtio_pci_common.h       |   9 +-
 drivers/virtio/virtio_pci_legacy.c       |  16 +-
 drivers/virtio/virtio_pci_modern.c       |  24 +-
 drivers/virtio/virtio_ring.c             | 698 ++++++++++++-----------
 drivers/virtio/virtio_vdpa.c             |  45 +-
 include/linux/virtio.h                   |  13 +-
 include/linux/virtio_config.h            |  48 +-
 include/linux/virtio_ring.h              |  82 +--
 tools/virtio/virtio_test.c               |   4 +-
 tools/virtio/vringh_test.c               |  28 +-
 17 files changed, 848 insertions(+), 618 deletions(-)

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2.32.0.3.g01195cf9f