Pull 9p updates from Dominique Martinet:
 "This contains mostly fixes (6 to be backported to stable) and a few
  changes, here is the breakdown:

   - rework how fids are attributed by replacing some custom tracking in
     a list by an idr

   - for packet-based transports (virtio/rdma) validate that the packet
     length matches what the header says

   - a few race condition fixes found by syzkaller

   - missing argument check when NULL device is passed in sys_mount

   - a few virtio fixes

   - some spelling and style fixes"

* tag '9p-for-4.19-2' of git://github.com/martinetd/linux: (21 commits)
  net/9p/trans_virtio.c: add null terminal for mount tag
  9p/virtio: fix off-by-one error in sg list bounds check
  9p: fix whitespace issues
  9p: fix multiple NULL-pointer-dereferences
  fs/9p/xattr.c: catch the error of p9_client_clunk when setting xattr failed
  9p: validate PDU length
  net/9p/trans_fd.c: fix race by holding the lock
  net/9p/trans_fd.c: fix race-condition by flushing workqueue before the kfree()
  net/9p/virtio: Fix hard lockup in req_done
  net/9p/trans_virtio.c: fix some spell mistakes in comments
  9p/net: Fix zero-copy path in the 9p virtio transport
  9p: Embed wait_queue_head into p9_req_t
  9p: Replace the fidlist with an IDR
  9p: Change p9_fid_create calling convention
  9p: Fix comment on smp_wmb
  net/9p/client.c: version pointer uninitialized
  fs/9p/v9fs.c: fix spelling mistake "Uknown" -> "Unknown"
  net/9p: fix error path of p9_virtio_probe
  9p/net/protocol.c: return -ENOMEM when kmalloc() failed
  net/9p/client.c: add missing '\n' at the end of p9_debug()
  ...