infiniband: qib: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

IB/qib: Convert qp_stats debugfs interface to use new iterator API

Continue porting copy/paste code into rdmavt from qib.

Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/hfi1,IB/qib: Fix qp_stats sleep with rcu read lock held

The qp init function does a kzalloc() while holding the RCU
lock that encounters the following warning with a debug kernel
when a cat of the qp_stats is done:

[ 231.723948] rcu_scheduler_active = 1, debug_locks = 0
[ 231.731939] 3 locks held by cat/11355:
[ 231.736492] #0: (debugfs_srcu){......}, at: [<ffffffff813001a5>] debugfs_use_file_start+0x5/0x90
[ 231.746955] #1: (&p->lock){+.+.+.}, at: [<ffffffff81289a6c>] seq_read+0x4c/0x3c0
[ 231.755873] #2: (rcu_read_lock){......}, at: [<ffffffffa0a0c535>] _qp_stats_seq_start+0x5/0xd0 [hfi1]
[ 231.766862]

The init functions do an implicit next which requires the rcu read lock
before the kzalloc().

Fix for both drivers is to change the scope of the init function to only
do the allocation and the initialization of the just allocated iter.

The implict next is moved back into the respective start functions to fix
the issue.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
CC: <stable@vger.kernel.org> # 4.6.x-
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/qib: Fix checkpatch warnings

Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/qib: Correct reference counting in debugfs qp_stats

This particular reference count is not needed with the rcu protection,
and the current code leaks a reference count, causing a hang in
qib_qp_destroy().

Cc: <stable@vger.kernel.org>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/qib: Add qp_stats debug file

This adds a seq_file iterator for reporting the QP hash table when the
qp_stats file is read.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/qib: Add per-context stats interface

This patch adds a debugfs stats interface for per kernel contexts
packet counts.

The code uses the opcode stats count and eliminates the counter in the
context.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

IB/qib: Convert opcode counters to per-context

This fix changes the opcode relative counters for receive to per
context.

Profiling has shown that when mulitple contexts are being used there
is a lot of cache activity associated with these counters.

The code formerly kept these counters per port, but only provided the
interface to read per HCA. This patch converts the read of counters
to per HCA and adds the debugfs hooks to be able to read the file as a
sequence of opcodes.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>