Currently, xprt_switch keeps a number of all xprts (xps_nxprts)
that were added to the switch regardless of whethere it's an
nconnect transport or a transport to a trunkable address.
Introduce a new counter to keep track of transports to unique
destination addresses per xprt_switch.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

  Features:

   - Multiple patches to add support for fcntl() leases over NFSv4.

   - A sysfs interface to display more information about the various
     transport connections used by the RPC client

   - A sysfs interface to allow a suitably privileged user to offline a
     transport that may no longer point to a valid server

   - A sysfs interface to allow a suitably privileged user to change the
     server IP address used by the RPC client

  Stable fixes:

   - Two sunrpc fixes for deadlocks involving privileged rpc_wait_queues

  Bugfixes:

   - SUNRPC: Avoid a KASAN slab-out-of-bounds bug in xdr_set_page_base()

   - SUNRPC: prevent port reuse on transports which don't request it.

   - NFSv3: Fix memory leak in posix_acl_create()

   - NFS: Various fixes to attribute revalidation timeouts

   - NFSv4: Fix handling of non-atomic change attribute updates

   - NFSv4: If a server is down, don't cause mounts to other servers to
     hang as well

   - pNFS: Fix an Oops in pnfs_mark_request_commit() when doing O_DIRECT

   - NFS: Fix mount failures due to incorrect setting of the
     has_sec_mnt_opts filesystem flag

   - NFS: Ensure nfs_readpage returns promptly when an internal error
     occurs

   - NFS: Fix fscache read from NFS after cache error

   - pNFS: Various bugfixes around the LAYOUTGET operation"

* tag 'nfs-for-5.14-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (46 commits)
  NFSv4/pNFS: Return an error if _nfs4_pnfs_v3_ds_connect can't load NFSv3
  NFSv4/pNFS: Don't call _nfs4_pnfs_v3_ds_connect multiple times
  NFSv4/pnfs: Clean up layout get on open
  NFSv4/pnfs: Fix layoutget behaviour after invalidation
  NFSv4/pnfs: Fix the layout barrier update
  NFS: Fix fscache read from NFS after cache error
  NFS: Ensure nfs_readpage returns promptly when internal error occurs
  sunrpc: remove an offlined xprt using sysfs
  sunrpc: provide showing transport's state info in the sysfs directory
  sunrpc: display xprt's queuelen of assigned tasks via sysfs
  sunrpc: provide multipath info in the sysfs directory
  NFSv4.1 identify and mark RPC tasks that can move between transports
  sunrpc: provide transport info in the sysfs directory
  SUNRPC: take a xprt offline using sysfs
  sunrpc: add dst_attr attributes to the sysfs xprt directory
  SUNRPC for TCP display xprt's source port in sysfs xprt_info
  SUNRPC query transport's source port
  SUNRPC display xprt's main value in sysfs's xprt_info
  SUNRPC mark the first transport
  sunrpc: add add sysfs directory per xprt under each xprt_switch
  ...

Using sysfs's xprt_state attribute, mark a particular transport offline.
It will not be picked during the round-robin selection. It's not allowed
to take the main (1st created transport associated with the rpc_client)
offline. Also bring a transport back online via sysfs by writing "online"
and that would allow for this transport to be picked during the round-
robin selection.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Allow to query and set the destination's address of a transport.
Setting of the destination address is allowed only for TCP or RDMA
based connections.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add individual transport directories under each transport switch
group. For instance, for each nconnect=X connections there will be
a transport directory. Naming conventions also identifies transport
type -- xprt-<id>-<type> where type is udp, tcp, rdma, local, bc.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Add xprt_switch directory to the sysfs and create individual
xprt_swith subdirectories for multipath transport group.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

This is used to uniquely identify sunrpc multipath objects in /sys.

Signed-off-by: Dan Aloni <dan@kernelim.com>
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

As xchg*() and cmpxchg*() may be instrumented by atomic-instrumented.h,
it's necessary to include <linux/atomic.h> to use these, rather than
<asm/cmpxchg.h>, which is effectively an arch-internal header.

In a couple of places we include <asm/cmpxchg.h>, but get away with this
as <linux/atomic.h> gets pulled in inidrectly by another include. Before
we convert more architectures to use atomic-instrumented.h, let's fix
these up to use <linux/atomic.h> so that we don't make things more
fragile.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210525140232.53872-3-mark.rutland@arm.com

Moves the balancing code to avoid doing cursor changes on every search
iteration.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Ensure that we do initialise the fields xps_nactive, xps_queuelen
and xps_net.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>