Use separate locks for the descriptor prep (producer) and descriptor
cleanup (consumer) paths.  Allows the producer path to run concurrently
with the cleanup path.  Inspired by Documentation/circular-buffer.txt.

Cc: David Howells <dhowells@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

If the calling convention of ->timer_fn() and ->cleanup_fn() are unified
across hardware versions we can drop parameters to ioat_init_channel() and
unify ioat_is_dma_complete() implementations.

Both ->timer_fn() and ->cleanup_fn() are modified to expect a struct
dma_chan pointer.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The hardware automatically disables further interrupts after each event
until rearmed.  This allows a delay to be injected between the occurence
of the interrupt and the running of the cleanup routine.  The delay is
scaled by the descriptor backlog and then written to the INTRDELAY
register which specifies the number of microseconds to hold off
interrupt delivery after an interrupt event occurs.  According to
powertop this reduces the interrupt rate from ~5000 intr/s to ~150
intr/s per without affecting throughput (simple dd to a raid6 array).
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Since ioat_cleanup_preamble() and the update of the last completed
descriptor are not synchronized there is a chance that two cleanup threads
can see descriptors to clean.  If the first cleans up all pending
descriptors then the second will trigger the BUG_ON.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Replace open coded ioat2_quiesce() call in ioat3_restart_channel
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

We already disallow raid operations while DCA is globally enabled, so
having it locally enabled is a nop and confusing when reading the code.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Put the ioat2 and ioat3 state machines in the halted state with all
errors cleared.

The ioat1 init path is not disturbed for stability, there are no
reported ioat1 initiaization issues.

Cc: <stable@kernel.org>
Reported-by: NRoland Dreier <rdreier@cisco.com>
Tested-by: NRoland Dreier <rdreier@cisco.com>
Acked-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

When continuing a pq calculation the driver needs 3 extra sources.  The
driver can perform a 3 source calculation with a single descriptor, but
needs an extended descriptor to process up to 8 sources in one
operation.  However, in the p-disabled case only one extra source is
needed.  When continuing a p-disabled operation there are occasions
(i.e. 0 < src_cnt % 8 < 3) where the tail operation does not need an
extended descriptor.  Properly account for this fact otherwise invalid
'dmacount' values will be written to hardware usually causing the
channel to halt with 'invalid descriptor' errors.

Cc: <stable@kernel.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The completion of a pq operation is notified with a null descriptor
appended to the end of the chain.  This descriptor needs to be visible
to dma clients otherwise the client is precluded from ensuring all
operations are quiesced before freeing channel resources, i.e. due to
descriptor polling it may get the completion notification ahead of the
interrupt delivered by the null descriptor.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

ioat3.2 does not support asynchronous error notifications which makes
the driver experience latencies when non-zero pq validate results are
expected.  Provide a mechanism for turning off async_xor_val and
async_syndrome_val via Kconfig.  This approach is generally useful for
any driver that specifies ASYNC_TX_DISABLE_CHANNEL_SWITCH and would like
to force the async_tx api to fall back to the synchronous path for
certain operations.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Modify is_ioat_bug() to catch all errors that are uncorrectable, or not
currently handled.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Although disabled, hardware still checks address validity, so duplicate
the known address.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

RAID operations cause a system hang on platforms with DCA
(Direct-Cache-Access) enabled.  So turn off RAID capabilities in this
case.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/dma/ioat/dma_v3.c: In function 'ioat3_prep_memset_lock':
drivers/dma/ioat/dma_v3.c:439: warning: 'fill' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c:437: warning: 'desc' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c: In function '__ioat3_prep_xor_lock':
drivers/dma/ioat/dma_v3.c:489: warning: 'xor' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c:486: warning: 'desc' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c: In function '__ioat3_prep_pq_lock':
drivers/dma/ioat/dma_v3.c:631: warning: 'pq' may be used uninitialized in this function
drivers/dma/ioat/dma_v3.c:628: warning: 'desc' may be used uninitialized in this function

gcc-4.0, unlike gcc-4.3, does not see that these variables are
initialized before use.  Convert the descriptor loops to do-while make
this initialization apparent.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The cleanup routine for the raid cases imposes extra checks for handling
raid descriptors and extended descriptors.  If the channel does not
support raid it can avoid this extra overhead by using the ioat2 cleanup
path.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The async_tx api uses the DMA_INTERRUPT operation type to terminate a
chain of issued operations with a callback routine.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

If a platform advertises pq capabilities, but not xor, then use
ioat3_prep_pqxor and ioat3_prep_pqxor_val to simulate xor support.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

ioat3.2 adds support for raid6 syndrome generation (xor sum of galois
field multiplication products) using up to 8 sources.  It can also
perform an pq-zero-sum operation to validate whether the syndrome for a
given set of sources matches a previously computed syndrome.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This adds a hardware specific self test to be called from ioat_probe.
In the ioat3 case we will have tests for all the different raid
operations, while ioat1 and ioat2 will continue to just test memcpy.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

ioat3.2 adds xor offload support for up to 8 sources.  It can also
perform an xor-zero-sum operation to validate whether all given sources
sum to zero, without writing to a destination.  Xor descriptors differ
from memcpy in that one operation may require multiple descriptors
depending on the number of sources.  When the number of sources exceeds
5 an extended descriptor is needed.  These descriptors need to be
accounted for when updating the DMA_COUNT register.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Tag completion writes for direct cache access to reduce the latency of
checking for descriptor completions.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Export driver attributes for diagnostic purposes:
'ring_size': total number of descriptors available to the engine
'ring_active': number of descriptors in-flight
'capabilities': supported operation types for this channel
'version': Intel(R) QuickData specfication revision

This also allows some chattiness to be removed from the driver startup
as this information is now available via sysfs.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Up until this point the driver for Intel(R) QuickData Technology
engines, specification versions 2 and 3, were mostly identical save for
a few quirks.  Version 3.2 hardware adds many new capabilities (like
raid offload support) requiring some infrastructure that is not relevant
for v2.  For better code organization of the new funcionality move v3
and v3.2 support to its own file dma_v3.c, and export some routines from
the base files (dma.c and dma_v2.c) that can be reused directly.

The first new capability included in this code reorganization is support
for v3.2 memset operations.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>