Given that the sprious wake-ups are common, we need to move the
condition setting right next to the wake_up().  After setting the condition
to req->status = REQ_STATUS_RCVD, sprious wakeups may cause the
virtqueue back on the free list for someone else to use.
This may result in kernel panic while relasing the pinned pages
in p9_release_req_pages().

Also rearranged the while loop in req_done() for better redability.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Process may wait to get space on VirtIO ring to send a transaction to
VirtFS server. Current code just does a conditional wake_up() which
means only one process will be woken up even if multiple processes
are waiting.

This fix makes the wake_up unconditional. Hence we won't have any
processes waiting for-ever.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This patch adds preferences field to the p9_trans_module.
Through this, now transport layer can express its preference about the
payload. i.e if payload neds to be part of the PDU or it prefers it
to be sent sepearetly so that the transport layer can handle it in
a better way.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Modify p9_virtio_request() and req_done() functions to support
additional payload sent down to the transport layer through
tc->pubuf and tc->pkbuf.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

If there is not enough space for the PDU on the VirtIO ring, current
code returns -EIO propagating the error to user.

This patch introduced a wqit_queue on the channel, and lets the process
wait on this queue until VirtIO ring frees up.
Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

p9_virtio_create will only compare the the channel's tag characters
against the device name till the end of the channel's tag but not till
the end of the device name. This means that if a user defines channels
with the tags foo and foobar then he would mount foo when he requested
foonot and may mount foo when he requested foobar.

Thus it is necessary to check both string lengths against each other in
case of a successful partial string match.
Signed-off-by: NSven Eckelmann <sven.eckelmann@gmx.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Switch trans_virtio to new virtqueue_xxx wrappers.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

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>

This adds a new file for virtio 9P device. The file
contain details of the mount device name that should
be used to mount the 9P file system.

Ex: /sys/devices/virtio-pci/virtio1/mount_tag  file now
contian the tag name to be used to mount the 9P file system.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This patch use the tag name in the config space to identify the
mount device. The the virtio device name depend on the enumeration
order of the device and may not remain the same across multiple boots
So we use the tag name which is set via qemu option to uniquely identify
the mount device
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

With this patch we have

# mount -t 9p -o trans=virtio virtio2 /mnt/
# mount -t 9p -o trans=virtio virtio2 /mnt/
mount: virtio2 already mounted or /mnt/ busy
mount: according to mtab, virtio2 is already mounted on /mnt
# mount -t 9p -o trans=virtio virtio3 /mnt/ -o debug=0xfff
mount: special device virtio3 does not exist
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Use a list to track the channel instead of statically
allocated array
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This is needed for supporting multiple mount points.

We can find out the device names to be used with mount by checking

/sys/devices/virtio-pci/virtio*/device file

if the device file have value 9 then the specific virtio device can
be used for mounting.

ex:
 #cat /sys/devices/virtio-pci/virtio1/device
 9

now we can mount using
# mount -t 9p -o trans=virtio virtio1  /mnt/
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The patch fix the crash repoted below

[   15.149907] BUG: unable to handle kernel NULL pointer dereference at 00000001
[   15.150806] IP: [<c140b886>] p9_virtio_close+0x18/0x24
.....
....
[   15.150806] Call Trace:
[   15.150806]  [<c1408e78>] ? p9_client_destroy+0x3f/0x163
[   15.150806]  [<c1409342>] ? p9_client_create+0x25f/0x270
[   15.150806]  [<c1063b72>] ? trace_hardirqs_on+0xb/0xd
[   15.150806]  [<c11ed4e8>] ? match_token+0x64/0x164
[   15.150806]  [<c1175e8d>] ? v9fs_session_init+0x2f1/0x3c8
[   15.150806]  [<c109cfc9>] ? kmem_cache_alloc+0x98/0xb8
[   15.150806]  [<c1063b72>] ? trace_hardirqs_on+0xb/0xd
[   15.150806]  [<c1173dd1>] ? v9fs_get_sb+0x47/0x1e8
[   15.150806]  [<c1173dea>] ? v9fs_get_sb+0x60/0x1e8
[   15.150806]  [<c10a2e77>] ? vfs_kern_mount+0x81/0x11a
[   15.150806]  [<c10a2f55>] ? do_kern_mount+0x33/0xbe
[   15.150806]  [<c10b40b9>] ? do_mount+0x654/0x6b3
[   15.150806]  [<c1038949>] ? do_page_fault+0x0/0x284
[   15.150806]  [<c10b28ec>] ? copy_mount_options+0x73/0xd2
[   15.150806]  [<c10b4179>] ? sys_mount+0x61/0x94
[   15.150806]  [<c14284e9>] ? syscall_call+0x7/0xb
....
[   15.203562] ---[ end trace 1dd159357709eb4b ]---
[
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The 9p virtio transport was not updating its connection status correctly
preventing it from being able to mount the server.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Rusty,

commit 3ca4f5ca
    virtio: add virtio IDs file
moved all device IDs into a single file. While the change itself is
a very good one, it can break userspace applications. For example
if a userspace tool wanted to get the ID of virtio_net it used to
include virtio_net.h. This does no longer work, since virtio_net.h
does not include virtio_ids.h.
This patch moves all "#include <linux/virtio_ids.h>" from the C
files into the header files, making the header files compatible with
the old ones.

In addition, this patch exports virtio_ids.h to userspace.

CC: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Virtio IDs are spread all over the tree which makes assigning new IDs
bothersome. Putting them together should make the process less error-prone.
Signed-off-by: NFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

VIRTIO_ID_9P is already defined in include/linux/virtio_9p.h
so use that definition instead.
Signed-off-by: NFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Eric Van Hensbergen <ericvh@gmail.com>

This API change means that virtio_net can tell how much capacity
remains for buffers.  It's necessarily fuzzy, since
VIRTIO_RING_F_INDIRECT_DESC means we can fit any number of descriptors
in one, *if* we can kmalloc.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Dinesh Subhraveti <dineshs@us.ibm.com>

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>

This replaces find_vq/del_vq with find_vqs/del_vqs virtio operations,
and updates all drivers. This is needed for MSI support, because MSI
needs to know the total number of vectors upfront.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (+ lguest/9p compile fixes)

Add a linked list of all virtqueues for a virtio device: this helps for
debugging and is also needed for upcoming interface change.

Also, add a "name" field for clearer debug messages.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

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>