Race scenario:

thread A			thread B

p9_write_work()                p9_fd_request()

if (list_empty
  (&m->unsent_req_list))
  ...

                               spin_lock(&client->lock);
                               req->status = REQ_STATUS_UNSENT;
                               list_add_tail(..., &m->unsent_req_list);
                               spin_unlock(&client->lock);
                               ....
                               if (n & POLLOUT &&
                               !test_and_set_bit(Wworksched, &m->wsched)
                               schedule_work(&m->wq);
                               --> not done because Wworksched is set

  clear_bit(Wworksched, &m->wsched);
  return;

--> nobody will take care of sending the new request.

This is not very likely to happen though, because p9_write_work()
being called with an empty unsent_req_list is not frequent.
But this also means that taking the lock earlier will not be costly.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Both modular callers of sock_map_fd() had been buggy; sctp one leaks
descriptor and file if copy_to_user() fails, 9p one shouldn't be
exposing file in the descriptor table at all.

Switch both to sock_alloc_file(), export it, unexport sock_map_fd() and
make it static.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

See previous commit about p9_read_work() for details.

This fixes a similar race between p9_write_work() and p9_poll_mux()
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

At the end of p9_write_work() we want to test if there is still data to send.
This means:
- either the current request still has data to send (wsize != 0)
- or there are requests in the unsent queue
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Race scenario between p9_read_work() and p9_poll_mux()

Data arrive, Rworksched is set, p9_read_work() is called.

thread A                                thread B

                                        p9_read_work()
                                                .
                                        reads data
                                                .
                                        checks if new data ready. No.
                                                .
                                        gets preempted
                                                .
More data arrive, p9_poll_mux() is called.      .
                                                .
                                                .
p9_poll_mux()                                   .
                                                .
if (!test_and_set_bit(Rworksched,               .
                      &m->wsched)) {            .
  schedule_work(&m->rq);                        .
}                                               .
                                                .
-> does not schedule work because               .
   Rworksched is set                            .
                                                .
                                        clear_bit(Rworksched, &m->wsched);
                                        return;

No work has been scheduled, and yet data are waiting.

Currently p9_read_work() checks if there is data to read,
and if not, it clears Rworksched.

I think it should clear Rworksched first, and then check if there is data to read.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

flush[_delayed]_work_sync() are now spurious.  Mark them deprecated
and convert all users to flush[_delayed]_work().

If you're cc'd and wondering what's going on: Now all workqueues are
non-reentrant and the regular flushes guarantee that the work item is
not pending or running on any CPU on return, so there's no reason to
use the sync flushes at all and they're going away.

This patch doesn't make any functional difference.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Mattia Dongili <malattia@linux.it>
Cc: Kent Yoder <key@linux.vnet.ibm.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: Bryan Wu <bryan.wu@canonical.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-wireless@vger.kernel.org
Cc: Anton Vorontsov <cbou@mail.ru>
Cc: Sangbeom Kim <sbkim73@samsung.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Petr Vandrovec <petr@vandrovec.name>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Avi Kivity <avi@redhat.com> 

Use of "unsigned int" is preferred to bare "unsigned" in net tree.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reduce object size by deduplicating formats.

Use vsprintf extension %pV.
Rename P9_DPRINTK uses to p9_debug, align arguments.
Add function for _p9_debug and macro to add __func__.
Add missing "\n"s to p9_debug uses.
Remove embedded function names as p9_debug adds it.
Remove P9_EPRINTK macro and convert use to pr_<level>.
Add and use pr_fmt and pr_<level>.

$ size fs/9p/built-in.o*
   text	   data	    bss	    dec	    hex	filename
  62133	    984	  16000	  79117	  1350d	fs/9p/built-in.o.new
  67342	    984	  16928	  85254	  14d06	fs/9p/built-in.o.old
$ size net/9p/built-in.o*
   text	   data	    bss	    dec	    hex	filename
  88792	   4148	  22024	 114964	  1c114	net/9p/built-in.o.new
  94072	   4148	  23232	 121452	  1da6c	net/9p/built-in.o.old
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Teach 9p filesystem to work in container with non-default network namespace.
(Note: I also patched the unix domain socket code but don't have a test case
for that.  It's the same fix, I just don't have a server for it...)

To test, run diod server (http://code.google.com/p/diod):
  diod -n -f -L stderr -l 172.23.255.1:9999 -c /dev/null -e /root
and then mount like so:
  mount -t 9p -o port=9999,aname=/root,version=9p2000.L 172.23.255.1 /mnt

A container test environment is described at http://landley.net/lxcSigned-off-by: NRob Landley <rob@landley.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Without this we can cause reclaim allocation in writepage.

[ 3433.448430] =================================
[ 3433.449117] [ INFO: inconsistent lock state ]
[ 3433.449117] 2.6.38-rc5+ #84
[ 3433.449117] ---------------------------------
[ 3433.449117] inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-R} usage.
[ 3433.449117] kswapd0/505 [HC0[0]:SC0[0]:HE1:SE1] takes:
[ 3433.449117]  (iprune_sem){+++++-}, at: [<ffffffff810ebbab>] shrink_icache_memory+0x45/0x2b1
[ 3433.449117] {RECLAIM_FS-ON-W} state was registered at:
[ 3433.449117]   [<ffffffff8107fe5f>] mark_held_locks+0x52/0x70
[ 3433.449117]   [<ffffffff8107ff02>] lockdep_trace_alloc+0x85/0x9f
[ 3433.449117]   [<ffffffff810d353d>] slab_pre_alloc_hook+0x18/0x3c
[ 3433.449117]   [<ffffffff810d3fd5>] kmem_cache_alloc+0x23/0xa2
[ 3433.449117]   [<ffffffff8127be77>] idr_pre_get+0x2d/0x6f
[ 3433.449117]   [<ffffffff815434eb>] p9_idpool_get+0x30/0xae
[ 3433.449117]   [<ffffffff81540123>] p9_client_rpc+0xd7/0x9b0
[ 3433.449117]   [<ffffffff815427b0>] p9_client_clunk+0x88/0xdb
[ 3433.449117]   [<ffffffff811d56e5>] v9fs_evict_inode+0x3c/0x48
[ 3433.449117]   [<ffffffff810eb511>] evict+0x1f/0x87
[ 3433.449117]   [<ffffffff810eb5c0>] dispose_list+0x47/0xe3
[ 3433.449117]   [<ffffffff810eb8da>] evict_inodes+0x138/0x14f
[ 3433.449117]   [<ffffffff810d90e2>] generic_shutdown_super+0x57/0xe8
[ 3433.449117]   [<ffffffff810d91e8>] kill_anon_super+0x11/0x50
[ 3433.449117]   [<ffffffff811d4951>] v9fs_kill_super+0x49/0xab
[ 3433.449117]   [<ffffffff810d926e>] deactivate_locked_super+0x21/0x46
[ 3433.449117]   [<ffffffff810d9e84>] deactivate_super+0x40/0x44
[ 3433.449117]   [<ffffffff810ef848>] mntput_no_expire+0x100/0x109
[ 3433.449117]   [<ffffffff810f0aeb>] sys_umount+0x2f1/0x31c
[ 3433.449117]   [<ffffffff8102c87b>] system_call_fastpath+0x16/0x1b
[ 3433.449117] irq event stamp: 192941
[ 3433.449117] hardirqs last  enabled at (192941): [<ffffffff81568dcf>] _raw_spin_unlock_irq+0x2b/0x30
[ 3433.449117] hardirqs last disabled at (192940): [<ffffffff810b5f97>] shrink_inactive_list+0x290/0x2f5
[ 3433.449117] softirqs last  enabled at (188470): [<ffffffff8105fd65>] __do_softirq+0x133/0x152
[ 3433.449117] softirqs last disabled at (188455): [<ffffffff8102d7cc>] call_softirq+0x1c/0x28
[ 3433.449117]
[ 3433.449117] other info that might help us debug this:
[ 3433.449117] 1 lock held by kswapd0/505:
[ 3433.449117]  #0:  (shrinker_rwsem){++++..}, at: [<ffffffff810b52e2>] shrink_slab+0x38/0x15f
[ 3433.449117]
[ 3433.449117] stack backtrace:
[ 3433.449117] Pid: 505, comm: kswapd0 Not tainted 2.6.38-rc5+ #84
[ 3433.449117] Call Trace:
[ 3433.449117]  [<ffffffff8107fbce>] ? valid_state+0x17e/0x191
[ 3433.449117]  [<ffffffff81036896>] ? save_stack_trace+0x28/0x45
[ 3433.449117]  [<ffffffff81080426>] ? check_usage_forwards+0x0/0x87
[ 3433.449117]  [<ffffffff8107fcf4>] ? mark_lock+0x113/0x22c
[ 3433.449117]  [<ffffffff8108105f>] ? __lock_acquire+0x37a/0xcf7
[ 3433.449117]  [<ffffffff8107fc0e>] ? mark_lock+0x2d/0x22c
[ 3433.449117]  [<ffffffff81081077>] ? __lock_acquire+0x392/0xcf7
[ 3433.449117]  [<ffffffff810b14d2>] ? determine_dirtyable_memory+0x15/0x28
[ 3433.449117]  [<ffffffff81081a33>] ? lock_acquire+0x57/0x6d
[ 3433.449117]  [<ffffffff810ebbab>] ? shrink_icache_memory+0x45/0x2b1
[ 3433.449117]  [<ffffffff81567d85>] ? down_read+0x47/0x5c
[ 3433.449117]  [<ffffffff810ebbab>] ? shrink_icache_memory+0x45/0x2b1
[ 3433.449117]  [<ffffffff810ebbab>] ? shrink_icache_memory+0x45/0x2b1
[ 3433.449117]  [<ffffffff810b5385>] ? shrink_slab+0xdb/0x15f
[ 3433.449117]  [<ffffffff810b69bc>] ? kswapd+0x574/0x96a
[ 3433.449117]  [<ffffffff810b6448>] ? kswapd+0x0/0x96a
[ 3433.449117]  [<ffffffff810714e2>] ? kthread+0x7d/0x85
[ 3433.449117]  [<ffffffff8102d6d4>] ? kernel_thread_helper+0x4/0x10
[ 3433.449117]  [<ffffffff81569200>] ? restore_args+0x0/0x30
[ 3433.449117]  [<ffffffff81071465>] ? kthread+0x0/0x85
[ 3433.449117]  [<ffffffff8102d6d0>] ? kernel_thread_helper+0x0/0x10
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Now that cmwq can handle high concurrency, it's more efficient to use
work than a dedicated kthread.  Convert p9_poll_proc() to a work
function for p9_poll_work and make p9_pollwake() schedule it on each
poll event.  The work is sync flushed on module exit.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: v9fs-developer@lists.sourceforge.net

With cmwq, there's no reason to use a dedicated workqueue in trans_fd.
Drop p9_mux_wq and use system_wq instead.  The used work items are
already sync canceled in p9_conn_destroy() and doesn't require further
synchronization.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: v9fs-developer@lists.sourceforge.net

The function has an unsigned return type, but returns a negative constant
to indicate an error condition.  The result of calling the function is
always stored in a variable of type (signed) int, and thus unsigned can be
dropped from the return type.

A sematic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@exists@
identifier f;
constant C;
@@

 unsigned f(...)
 { <+...
*  return -C;
 ...+> }
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is an off by one bug because strlen() doesn't count the NULL
terminator.  We strcpy() addr into a fixed length array of size
UNIX_PATH_MAX later on.

The addr variable is the name of the device being mounted.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This is an off by one bug because strlen() doesn't count the NULL
terminator.  We strcpy() addr into a fixed length array of size
UNIX_PATH_MAX later on.

The addr variable is the name of the device being mounted.

CC: stable@kernel.org
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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>

Options pointer is being moved before calling kfree() which seems
to cause problems.  This uses a separate pointer to track and free
original allocation.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@us.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>w

* if we fail in p9_conn_create(), we shouldn't leak references to struct file.
  Logics in ->close() doesn't help - ->trans is already gone by the time it's
  called.
* sock_create_kern() can fail.
* use of sock_map_fd() is all fscked up; I'd fixed most of that, but the
  rest will have to wait for a bit more work in net/socket.c (we still are
  violating the basic rule of working with descriptor table: "once the reference
  is installed there, don't rely on finding it there again").
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Not including net/atm/

Compiled tested x86 allyesconfig only
Added a > 80 column line or two, which I ignored.
Existing checkpatch plaints willfully, cheerfully ignored.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix the comments -- mostly the improper and/or missing descriptions
of function parameters.
Signed-off-by: NAbhishek Kulkarni <adkulkar@umail.iu.edu>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

It is not safe to use match_int without checking the token type returned
by match_token (especially when the token type returned is Opt_err and
args is empty). Fix it.
Signed-off-by: NAbhishek Kulkarni <adkulkar@umail.iu.edu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently the 9p code crashes when a operation is interrupted, i.e. for
example when the user presses ^C while reading from a file.

This patch fixes the code that is responsible for interruption and flushing
of 9P operations.
Signed-off-by: NLatchesar Ionkov <lucho@ionkov.net>

Impact: Trust in the comment and add '__force' to the cast.

Fix this sparse warning:
  net/9p/trans_fd.c:420:34: warning: cast adds address space to expression (<asn:1>)
Signed-off-by: NHannes Eder <hannes@hanneseder.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes build problem with 9p when building with debug disabled.
Also contains some fixes for warnings which pop up when 
CONFIG_NET_9P_DEBUG is disabled.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

During the reorganization some of the multi-theaded locking assumptions were
accidently relaxed.  This patch moves us back towards a more conservative 
locking strategy.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Now that the new protocol functions are in place, this patch switches
the client code to using the new support code.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This removes the vestigial tag field from the p9_req_t structure.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

One of the current debug options allows users to get a verbose dump of fcalls.
This isn't really necessary as correctly parsed protocol frames can be printed
as part of the code in the client functions.  The consolidated printfcalls
structure would require new entries to be added for every extension.  This
patch removes the debug print methods and their use.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Post p9_fd_poll() error path which checks m->poll_waddr[i] for PTR_ERR
value has the following problems.

* It's completely unused.  Error value is set iff NULL @wait_address
  has been specified to p9_pollwait() which is guaranteed not to
  happen.

* It dereferences @m after deallocating it (introduced by 571ffeaf and
  spotted by Raja R Harinath.

* It returned the wrong value on error.  It should return
  poll_waddr[i] but it returnes poll_waddr (introduced by 571ffeaf).

* p9_mux_poll_stop() doesn't handle PTR_ERR value.  It will try to
  operate on the PTR_ERR value as if it's a normal pointer and cause
  oops.

As the error path is bogus in the first place, there's no reason to
hold onto it.  Kill it.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>
Cc: Raja R Harinath <harinath@hurrynot.org>

This code moves the rpc function to the common client base,
reorganizes the flush code to be more simple and stable, and
makes the necessary adjustments to the underlying transports
to adapt to the new structure.

This reduces the overall amount of code duplication between the
transports and should make adding new transports more straightforward.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This patch reworks the read_work function to enable it to directly use a passed
in rcall structure.  This should help allow us to remove unnecessary copies
in the future.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Apply the now common p9_req_t structure to the fd transport.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Simplify trans_fd by using new common client tagpool structure.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The current trans_fd rpc mechanisms use a dynamic callback mechanism which
introduces a lot of complexity which only accomodates a single special case.
This patch removes much of that complexity in favor of a simple exception
mechanism to deal with flushes.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Currently, trans_fd has two structures (p9_req and p9_mux-rpc)
which contain mostly duplicate data.

This patch consolidates these two structures and removes p9_mux_rpc.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Cleanup files by reordering functions in order to remove need for
unnecessary function prototypes.

There are no code changes here, just functions being moved around and
prototypes being eliminated.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Now that we are passing client state into the transport modules, remove
duplicate state which is present in transport private structures.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Right now there is a transport module structure which provides per-transport
type functions and data and a transport structure which contains per-instance
public data as well as function pointers to instance specific functions.

This patch moves public transport visible instance data to the client
structure (which in some cases had duplicate data) and consolidates the
functions into the transport module structure.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

trans_fd used pool of upto 100 pollers to monitor the r/w fds.  The
approach makes sense in userspace back when the only available
interfaces were poll(2) and select(2).  As each event monitor -
trigger - handling iteration took O(n) where `n' is the number of
watched fds, it makes sense to spread them to many pollers such that
the `n' can be divided by the number of pollers.  However, this
doesn't make any sense in kernel because persistent edge triggered
event monitoring is how the whole thing is implemented in the kernel
in the first place.

This patch converts trans_fd to use single poller which watches all
the fds instead of the poll of pollers approach.  All the fds are
registered for monitoring on creation and only the fds with pending
events are scanned when something happens much like how epoll is
implemented.

This change makes trans_fd fd monitoring more efficient and simpler.
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>