This patch series enforces a limit on the number of v4 clients allowed
in the system. With Courteous server support there are potentially a
lots courtesy clients exist in the system that use up memory resource
preventing them to be used by other components in the system. Also
without a limit on the number of clients, the number of clients can
grow to a very large number even for system with small memory configuration
eventually render the system into an unusable state.

v2:
. move all defines to nfsd.h
. replace unsigned int nfs4_max_client to int
. kick start laundromat in alloc_client when max client reached.
. restyle compute of maxreap in nfs4_get_client_reaplist to oneline.
. redo enforce of maxreap in nfs4_get_client_reaplist for readability
. use bit-wise interger to compute usable memory in nfsd_init_net.
. replace NFS4_MAX_CLIENTS_PER_4GB to NFS4_CLIENTS_PER_GB.
. use all memory, including high mem, to compute max client.

v3:
. refactoring v4 initialization specific code to a helper in nfs4state.c
. fix kernel test robot issue with NFS4_CLIENTS_PER_GB when
  CONFIG_NFSD_V4 is not defined by moving v4 specific code
  to helper nfsd4_init_leases_net in nfs4state.c 

---

Dai Ngo (2):
      NFSD: refactoring v4 specific code to a helper in nfs4state.c
      NFSD: keep track of the number of v4 clients in the system
      NFSD: limit the number of v4 clients to 1024 per 1GB of system memory

 fs/nfsd/netns.h     |  3 +++
 fs/nfsd/nfs4state.c | 49 ++++++++++++++++++++++++++++++++++++++++--------
 fs/nfsd/nfsctl.c    |  9 +--------
 fs/nfsd/nfsd.h      |  6 ++++++
 4 files changed, 51 insertions(+), 16 deletions(-)

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Dai Ngo