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>

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>

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

The virtio transport uses a simplified request management system
that I want to use for all transports.  This patch adapts and moves the
exisiting code for managing requests to the client common code.
Later patches will apply these mechanisms to the other transports.
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>

9p trans modules aren't refcounted nor were they unregistered
properly.  Fix it.

* Add 9p_trans_module->owner and reference the module on each trans
  instance creation and put it on destruction.

* Protect v9fs_trans_list with a spinlock.  This isn't strictly
  necessary as the list is manipulated only during module loading /
  unloading but it's a good idea to make the API safe.

* Unregister trans modules when the corresponding module is being
  unloaded.

* While at it, kill unnecessary EXPORT_SYMBOL on p9_trans_fd_init().
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Some files in the net/9p directory uses "int" for flags. This can
cause hard to find bugs on some architectures. This patch converts the
flags to use "long" instead.

This bug was discovered by doing an allyesconfig make on the -rt kernel
where checks are done to ensure all flags are of size sizeof(long).
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Acked-by: NEric Van Hensbergen <ericvh@gmail.com>

Replace semaphores protecting use flags with a mutex.
Signed-off-by: NJosef 'Jeff' Sipek <jeffpc@josefsipek.net>
Acked-by: NEric Van Hensbergen <ericvh@gmail.com>

The kernel-doc comments of much of the 9p system have been in disarray since
reorganization.  This patch fixes those problems, adds additional documentation
and a template book which collects the 9p information.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The Coverity checker spotted that less memory than required was
allocated.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

if (...) BUG(); should be replaced with BUG_ON(...) when the test has no
side-effects to allow a definition of BUG_ON that drops the code completely.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@ disable unlikely @ expression E,f; @@

(
  if (<... f(...) ...>) { BUG(); }
|
- if (unlikely(E)) { BUG(); }
+ BUG_ON(E);
)

@@ expression E,f; @@

(
  if (<... f(...) ...>) { BUG(); }
|
- if (E) { BUG(); }
+ BUG_ON(E);
)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This merges the mux.c (including the connection interface) with trans_fd
in preparation for transport API changes.  Ultimately, trans_fd will need
to be rewritten to clean it up and simplify the implementation, but this
reorganization is viewed as the first step.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Request from rusty:
Just cleaning up patches for 2.6.25 merge, and noticed that
net/9p/trans_virtio.c doesn't have a remove function.  This will crash when
removing the module (console doesn't have one because it can't really be
removed).
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This fixes a poorly placed spinlock which could result in a
soft lockup condition.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This replaces the console-based virto client with a block-based
client using a single request queue.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

It seems that virtio_net wants to disable callbacks (interrupts) before
calling netif_rx_schedule(), so we can't use the return value to do so.

Rename "restart" to "cb_enable" and introduce "cb_disable" hook: callback
now returns void, rather than a boolean.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Previously we used a type/len pair within the config space, but this
seems overkill.  We now simply define a structure which represents the
layout in the config space: the config space can now only be extended
at the end.

The main driver-visible changes:
1) We indicate what fields are present with an explicit feature bit.
2) Virtqueues are explicitly numbered, and not in the config space.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

This adds a transport to 9p for communicating between guests and a host
using a virtio based transport.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>