RDMA/nldev: Fix locking when accessing mr->pd

Sashiko points out that, due to rereg_mr, the PD is actually variable and
all the touches in nldev are racy.

Use mr->device instead of mr->pd->device.

Getting the PD restrack ID is more tricky. To avoid disturbing all the
happy paths, add an rdma_restrack_sync() operation which is sort of like
flush_workqueue() or synchronize_irq(): after it returns, all the old
nldev touches to the mr are gone and everything sees the new PD. This
makes it safe to reach into the PD pointer.

Fixes: da5c85078215 ("RDMA/nldev: add driver-specific resource tracking")
Link: https://patch.msgid.link/r/4-v1-29ebd2c229b5+fd5-ib_mr_pd_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

0 files changed, 0 insertions, 0 deletions