[RFC 0/4] pci/sriov: support VFs dynamic addition

["Longpeng(Mike)" <longpeng2@huawei.com>]

From: Longpeng <longpeng2@huawei.com>

We can enable SRIOV and add VFs by /sys/bus/pci/devices/..../sriov_numvfs, but
this operation needs to spend lots of time if there has a large amount of VFs.      
                                                            
For example, if the machine has 10 PFs and 250 VFs per-PF, enable all the VFs
concurrently would cost about 200-250ms. However most of them are not need to be
used at the moment, so we can enable SRIOV first but add VFs on demand.

This series introduces two interfaces:
1. sriov_numvfs_no_scan: enable SRIOV without add the VFs.
2. sriov_scan_vf_id: add a specific VF.

Longpeng (4):
  pci/sriov: extract sriov_numvfs common helper
  pci/sriov: add vf_bitmap to mark the vf id allocation
  pci/sriov: add sriov_numfs_no_scan interface
  pci/sriov: add sriov_scan_vf_id interface

 drivers/pci/iov.c | 162 +++++++++++++++++++++++++++++++++++++++++-----
 drivers/pci/pci.h |   1 +
 2 files changed, 148 insertions(+), 15 deletions(-)

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2.23.0