RPC-over-RDMA needs to separate its RPC call and reply buffers.

 o When an RPC Call is sent, rq_snd_buf is DMA mapped for an RDMA
   Send operation using DMA_TO_DEVICE

 o If the client expects a large RPC reply, it DMA maps rq_rcv_buf
   as part of a Reply chunk using DMA_FROM_DEVICE

The two mappings are for data movement in opposite directions.

DMA-API.txt suggests that if these mappings share a DMA cacheline,
bad things can happen. This could occur in the final bytes of
rq_snd_buf and the first bytes of rq_rcv_buf if the two buffers
happen to share a DMA cacheline.

On x86_64 the cacheline size is typically 8 bytes, and RPC call
messages are usually much smaller than the send buffer, so this
hasn't been a noticeable problem. But the DMA cacheline size can be
larger on other platforms.

Also, often rq_rcv_buf starts most of the way into a page, thus
an additional RDMA segment is needed to map and register the end of
that buffer. Try to avoid that scenario to reduce the cost of
registering and invalidating Reply chunks.

Instead of carrying a single regbuf that covers both rq_snd_buf and
rq_rcv_buf, each struct rpcrdma_req now carries one regbuf for
rq_snd_buf and one regbuf for rq_rcv_buf.

Some incidental changes worth noting:

- To clear out some spaghetti, refactor xprt_rdma_allocate.
- The value stored in rg_size is the same as the value stored in
  the iov.length field, so eliminate rg_size
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Currently there's a hidden and indirect mechanism for finding the
rpcrdma_req that goes with an rpc_rqst. It depends on getting from
the rq_buffer pointer in struct rpc_rqst to the struct
rpcrdma_regbuf that controls that buffer, and then to the struct
rpcrdma_req it goes with.

This was done back in the day to avoid the need to add a per-rqst
pointer or to alter the buf_free API when support for RPC-over-RDMA
was introduced.

I'm about to change the way regbuf's work to support larger inline
thresholds. Now is a good time to replace this indirect mechanism
with something that is more straightforward. I guess this should be
considered a clean up.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

For xprtrdma, the RPC Call and Reply buffers are involved in real
I/O operations.

To start with, the DMA direction of the I/O for a Call is opposite
that of a Reply.

In the current arrangement, the Reply buffer address is on a
four-byte alignment just past the call buffer. Would be friendlier
on some platforms if that was at a DMA cache alignment instead.

Because the current arrangement allocates a single memory region
which contains both buffers, the RPC Reply buffer often contains a
page boundary in it when the Call buffer is large enough (which is
frequent).

It would be a little nicer for setting up DMA operations (and
possible registration of the Reply buffer) if the two buffers were
separated, well-aligned, and contained as few page boundaries as
possible.

Now, I could just pad out the single memory region used for the pair
of buffers. But frequently that would mean a lot of unused space to
ensure the Reply buffer did not have a page boundary.

Add a separate pointer to rpc_rqst that points right to the RPC
Reply buffer. This makes no difference to xprtsock, but it will help
xprtrdma in subsequent patches.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

xprtrdma needs to allocate the Call and Reply buffers separately.
TBH, the reliance on using a single buffer for the pair of XDR
buffers is transport implementation-specific.

Instead of passing just the rq_buffer into the buf_free method, pass
the task structure and let buf_free take care of freeing both
XDR buffers at once.

There's a micro-optimization here. In the common case, both
xprt_release and the transport's buf_free method were checking if
rq_buffer was NULL. Now the check is done only once per RPC.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

xprtrdma needs to allocate the Call and Reply buffers separately.
TBH, the reliance on using a single buffer for the pair of XDR
buffers is transport implementation-specific.

Transports that want to allocate separate Call and Reply buffers
will ignore the "size" argument anyway.  Don't bother passing it.

The buf_alloc method can't return two pointers. Instead, make the
method's return value an error code, and set the rq_buffer pointer
in the method itself.

This gives call_allocate an opportunity to terminate an RPC instead
of looping forever when a permanent problem occurs. If a request is
just bogus, or the transport is in a state where it can't allocate
resources for any request, there needs to be a way to kill the RPC
right there and not loop.

This immediately fixes a rare problem in the backchannel send path,
which loops if the server happens to send a CB request whose
call+reply size is larger than a page (which it shouldn't do yet).

One more issue: looks like xprt_inject_disconnect was incorrectly
placed in the failure path in call_allocate. It needs to be in the
success path, as it is for other call-sites.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: there is some XDR initialization logic that is common
to the forward channel and backchannel. Move it to an XDR header
so it can be shared.

rpc_rqst::rq_buffer points to a buffer containing big-endian data.
Update its annotation as part of the clean up.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up: r_xprt is already available everywhere these macros are
invoked, so just dereference that directly.

RPCRDMA_INLINE_PAD_VALUE is no longer used, so it can simply be
removed.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Try all multipath addresses for a data server. The first address that
successfully connects and creates a session is the DS mount address.
All subsequent addresses are tested for session trunking and
added as aliases.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Use an async exchange id call to test for session trunking

To conform with RFC 5661 section 18.35.4, the Non-Update on
Existing Clientid case, save the exchange id verifier in
cl_confirm and use it for the session trunking exhange id test.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Use a setup function to call into the NFS layer to test an rpc_xprt
for session trunking so as to not leak the rpc_xprt_switch into
the nfs layer.

Search for the address in the rpc_xprt_switch first so as not to
put an unnecessary EXCHANGE_ID on the wire.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Give the NFS layer access to the rpc_xprt_switch_add_xprt function
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Give the NFS layer access to the xprt_switch_put function
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

rpc_task_set_client is only called from rpc_run_task after
rpc_new_task and rpc_task_release_client is not needed as the
task is new.

When called from rpc_new_task, rpc_task_set_client also removed the
assigned rpc_xprt which is not desired.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

For session trunking, to compare nfs41_exchange_id_res with
existing nfs_client
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

For session trunking, to compare nfs41_exchange_id_res with
exiting nfs_client.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Testing an rpc_xprt for session trunking should not delay application
progress over already established transports.
Setup exchange_id to be able to be an async call to test an rpc_xprt
for session trunking use.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Add support for the kernel parameter nfs.callback_nr_threads to set
the number of threads that will be assigned to the callback channel.

Add support for the kernel parameter nfs.nfs.max_session_cb_slots
to set the maximum size of the callback channel slot table.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

This will allow us to bump the number of callback threads at will.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Ensure that the nfs_callback_info[] array correctly tracks the
struct svc_serv.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Clean up.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

In order to manage the threads using svc_set_num_threads, we need to
fill in a few extra fields.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Current NFSv4.1/pNFS client assumes that MDS supports only one layout
type. While it's true for most existing servers, nevertheless, this can
be change in the near future.

For now, this patch just plumbs in the ability to track a list of
layouts in the fsinfo structure. The existing behavior of the client
is preserved, by having it just select the first entry in the list.
Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: Jeff Layton <jlayton@poochiereds.net>
Reviewed-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

The variable `err` is not used anywhere and just returns the
predefined value `0` at the end of the function. Hence, remove the
variable and return 0 explicitly.
Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

Pull USB fixes from Greg KH:
 "Here are two small fixes, and one new device id, for 4.8-rc7

  The fixes solve a build error that was reported in your tree for the
  blackfin arch, and resolve an issue with a number of broken USB
  devices that reported the wrong interval rate.  Included here is also
  a new device id for the usb-serial driver.

  All have been in linux-next with no reported issues"

* tag 'usb-4.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: change bInterval default to 10 ms
  usb: musb: Fix tusb6010 compile error on blackfin
  USB: serial: simple: add support for another Infineon flashloader

Merge tag 'fixes-for-linus-v4.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull uaccess fixes from Guenter Roeck:
 "Two patches fixing problems introduced with copy_from_user changes"

* tag 'fixes-for-linus-v4.8-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  openrisc: fix the fix of copy_from_user()
  avr32: fix 'undefined reference to `___copy_from_user'

Pull perf fixes from Thomas Gleixner:
 "A couple of small fixes to x86 perf drivers:

   - Measure L2 for HW_CACHE* events on AMD

   - Fix the address filter handling in the intel/pt driver

   - Handle the BTS disabling at the proper place"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/amd: Make HW_CACHE_REFERENCES and HW_CACHE_MISSES measure L2
  perf/x86/intel/pt: Do validate the size of a kernel address filter
  perf/x86/intel/pt: Fix kernel address filter's offset validation
  perf/x86/intel/pt: Fix an off-by-one in address filter configuration
  perf/x86/intel: Don't disable "intel_bts" around "intel" event batching

Pull SMP build fixlet from Thomas Gleixner:
 "Add a missing include in cpuhotplug.h"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/hotplug: Include linux/types.h in linux/cpuhotplug.h

Pull irq fixes from Thomas Gleixner:
 "Two patches from Boris which address a potential deadlock in the atmel
  irq chip driver"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/atmel-aic: Fix potential deadlock in ->xlate()
  genirq: Provide irq_gc_{lock_irqsave,unlock_irqrestore}() helpers

Since commit acb2505d ("openrisc: fix copy_from_user()"),
copy_from_user() returns the number of bytes requested, not the
number of bytes not copied.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Fixes: acb2505d ("openrisc: fix copy_from_user()")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

avr32 builds fail with:

arch/avr32/kernel/built-in.o: In function `arch_ptrace':
(.text+0x650): undefined reference to `___copy_from_user'
arch/avr32/kernel/built-in.o:(___ksymtab+___copy_from_user+0x0): undefined
reference to `___copy_from_user'
kernel/built-in.o: In function `proc_doulongvec_ms_jiffies_minmax':
(.text+0x5dd8): undefined reference to `___copy_from_user'
kernel/built-in.o: In function `proc_dointvec_minmax_sysadmin':
sysctl.c:(.text+0x6174): undefined reference to `___copy_from_user'
kernel/built-in.o: In function `ptrace_has_cap':
ptrace.c:(.text+0x69c0): undefined reference to `___copy_from_user'
kernel/built-in.o:ptrace.c:(.text+0x6b90): more undefined references to
`___copy_from_user' follow

Fixes: 8630c322 ("avr32: fix copy_from_user()")
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Havard Skinnemoen <hskinnemoen@gmail.com>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

... by turning it into what used to be multipages counterpart

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull MMC fixes from Ulf Hansson:
 "MMC host:
   - omap/omap_hsmmc: Initialize dma_slave_config to avoid random data
   - sdhci-st: Handle interconnect clock"

* tag 'mmc-v4.8-rc6' of git://git.linaro.org/people/ulf.hansson/mmc:
  mmc: omap: Initialize dma_slave_config to avoid random data in it's fields
  mmc: omap_hsmmc: Initialize dma_slave_config to avoid random data
  mmc: sdhci-st: Handle interconnect clock
  dt-bindings: mmc: sdhci-st: Mention the discretionary "icn" clock

Pull powerpc fixes from Michael Ellerman:
 "Fixes for code merged this cycle:

   - Fix restore of SPRs upon wake up from hypervisor state loss from
     Gautham R  Shenoy
   - Fix the state of root PE from Gavin Shan
   - Detach from PE on releasing PCI device from Gavin Shan
   - Fix size of NUM_CPU_FTR_KEYS on 32-bit
   - Fix missed TCE invalidations that should fallback to OPAL"

* tag 'powerpc-4.8-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/powernv/pci: Fix missed TCE invalidations that should fallback to OPAL
  powerpc/powernv: Detach from PE on releasing PCI device
  powerpc/powernv: Fix the state of root PE
  powerpc/kernel: Fix size of NUM_CPU_FTR_KEYS on 32-bit
  powerpc/powernv: Fix restore of SPRs upon wake up from hypervisor state loss

Pull cifs fixes from Steve French:
 "Small set of cifs fixes"

* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
  Move check for prefix path to within cifs_get_root()
  Compare prepaths when comparing superblocks
  Fix memory leaks in cifs_do_mount()

Pull nfsd bugfix from Bruce Fields:
 "Fix a memory corruption bug that I introduced in 4.7"

* tag 'nfsd-4.8-2' of git://linux-nfs.org/~bfields/linux:
  svcauth_gss: Revert 64c59a37 ("Remove unnecessary allocation")

Pull drm fixes from Dave Airlie:
 "Two sets of i915 fixes, one set of vc4 crasher fixes, and a couple of
  atmel fixes.

  Nothing too out there at this stage, though I think some people are
  holidaying so it's been quiet enough"

* tag 'drm-fixes-for-4.8-rc6' of git://people.freedesktop.org/~airlied/linux:
  drm/i915: Ignore OpRegion panel type except on select machines
  Revert "drm/i915/psr: Make idle_frames sensible again"
  drm/i915: Restore lost "Initialized i915" welcome message
  drm/vc4: mark vc4_bo_cache_purge() static
  drm/i915: Add GEN7_PCODE_MIN_FREQ_TABLE_GT_RATIO_OUT_OF_RANGE to SNB
  drm/i915: disable 48bit full PPGTT when vGPU is active
  drm/i915: enable vGPU detection for all
  drm/atmel-hlcdc: Make ->reset() implementation static
  drm: atmel-hlcdc: Fix vertical scaling
  drm/vc4: Allow some more signals to be packed with uniform resets.
  drm/i915/dvo: Remove dangling call to drm_encoder_cleanup()