... and have get_user_pages_fast() mapping fewer pages than requested
to generate a short read/write.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

On device hot-unplug, 9p/virtio currently will kfree channel while
it might still be in use.

Of course, it might stay used forever, so it's an extremely ugly hack,
but it seems better than use-after-free that we have now.

[ Unused variable removed, whitespace cleanup, msg single-lined --RR ]
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Having to say
> #ifdef CONFIG_NET_NS
> 	struct net *net;
> #endif

in structures is a little bit wordy and a little bit error prone.

Instead it is possible to say:
> typedef struct {
> #ifdef CONFIG_NET_NS
>       struct net *net;
> #endif
> } possible_net_t;

And then in a header say:

> 	possible_net_t net;

Which is cleaner and easier to use and easier to test, as the
possible_net_t is always there no matter what the compile options.

Further this allows read_pnet and write_pnet to be functions in all
cases which is better at catching typos.

This change adds possible_net_t, updates the definitions of read_pnet
and write_pnet, updates optional struct net * variables that
write_pnet uses on to have the type possible_net_t, and finally fixes
up the b0rked users of read_pnet and write_pnet.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some devices might not implement config space access
(e.g. remoteproc used not to - before 3.9).
virtio/9p needs config space access so make it
fail gracefully if not there.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

virtio spec requires drivers to set DRIVER_OK before using VQs.
This is set automatically after probe returns, but virtio 9p device
adds self to channel list within probe, at which point VQ can be
used in violation of the spec.

To fix, call virtio_device_ready before using VQs.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When parsing options, make sure we have found a proper token before
doing a numeric conversion.

Without this check, the current code will end up following random
pointers that just happened to be on the stack when this function was
called, because match_token() will not touch the 'args' list unless a
valid token is found.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

There is no point in allocating these structs separately.
Changing this makes the code a little simpler and saves a few bytes of
memory.

Reported-by: Herve Vico
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This request state is mostly useless, and properly implementing it
for RDMA would require an extra lock to be taken in handle_recv()
and in rdma_cancel() to avoid this race:

    handle_recv()           rdma_cancel()
        .                     .
        .                   if req->state == SENT
    req->state = RCVD         .
        .                           req->state = FLSH

So just get rid of it.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Take into account posted recv buffers that will never receive their
reply.

The RDMA code posts a recv buffer for each request that it sends.
When a request is flushed, it is possible that this request will
never receive a reply, and that one recv buffer will stay unused on
the recv queue.

It is then possible, if this scenario happens several times, to have the
recv queue full, and have the 9pnet_rmda module unable to send new requests.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This will be needed by the flush logic.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

And move transport-specific code out of net/9p/client.c
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Mark function as static in net/9p/client.c because it is not used
outside this file.

This eliminates the following warning in net/9p/client.c:
net/9p/client.c:207:18: warning: no previous prototype for ‘p9_fcall_alloc’ [-Wmissing-prototypes]
Signed-off-by: NRashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

We need barriers to guarantee this pattern works as intended:
[w] req->rc, 1		[r] req->status, 1
wmb			rmb
[w] req->status, 1	[r] req->rc

Where the wmb ensures that rc gets written before status,
and the rmb ensures that if you observe status == 1, rc is the new value.
Signed-off-by: NDominique Martinet <dominique.martinet@cea.fr>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The 9p-virtio transport does zero copy on things larger than 1024 bytes
in size. It accomplishes this by returning the physical addresses of
pages to the virtio-pci device. At present, the translation is usually a
bit shift.

That approach produces an invalid page address when we read/write to
vmalloc buffers, such as those used for Linux kernel modules. Any
attempt to load a Linux kernel module from 9p-virtio produces the
following stack.

[<ffffffff814878ce>] p9_virtio_zc_request+0x45e/0x510
[<ffffffff814814ed>] p9_client_zc_rpc.constprop.16+0xfd/0x4f0
[<ffffffff814839dd>] p9_client_read+0x15d/0x240
[<ffffffff811c8440>] v9fs_fid_readn+0x50/0xa0
[<ffffffff811c84a0>] v9fs_file_readn+0x10/0x20
[<ffffffff811c84e7>] v9fs_file_read+0x37/0x70
[<ffffffff8114e3fb>] vfs_read+0x9b/0x160
[<ffffffff81153571>] kernel_read+0x41/0x60
[<ffffffff810c83ab>] copy_module_from_fd.isra.34+0xfb/0x180

Subsequently, QEMU will die printing:

qemu-system-x86_64: virtio: trying to map MMIO memory

This patch enables 9p-virtio to correctly handle this case. This not
only enables us to load Linux kernel modules off virtfs, but also
enables ZFS file-based vdevs on virtfs to be used without killing QEMU.

Special thanks to both Avi Kivity and Alexander Graf for their
interpretation of QEMU backtraces. Without their guidence, tracking down
this bug would have taken much longer. Also, special thanks to Linus
Torvalds for his insightful explanation of why this should use
is_vmalloc_addr() instead of is_vmalloc_or_module_addr():

https://lkml.org/lkml/2014/2/8/272Signed-off-by: NRichard Yao <ryao@gentoo.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Mark function as static in net/9p/client.c because it is not used
outside this file.

This eliminates the following warning in net/9p/client.c:
net/9p/client.c:207:18: warning: no previous prototype for ‘p9_fcall_alloc’ [-Wmissing-prototypes]
Signed-off-by: NRashika Kheria <rashika.kheria@gmail.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A few releases back a patch made virtio the default transport, however
it was done in a way which side-stepped the mechanism put in place to
allow for this selection.  This patch cleans that up while maintaining
virtio as the default transport.
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This lets the transport do endian conversion if necessary, and insulates
the drivers from the difference.

Most drivers can use the simple helpers virtio_cread() and virtio_cwrite().
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

During trinity fuzzing in a kvmtool guest, I stumbled across the
following:

Unable to handle kernel NULL pointer dereference at virtual address 00000004
PC is at v9fs_file_do_lock+0xc8/0x1a0
LR is at v9fs_file_do_lock+0x48/0x1a0
[<c01e2ed0>] (v9fs_file_do_lock+0xc8/0x1a0) from [<c0119154>] (locks_remove_flock+0x8c/0x124)
[<c0119154>] (locks_remove_flock+0x8c/0x124) from [<c00d9bf0>] (__fput+0x58/0x1e4)
[<c00d9bf0>] (__fput+0x58/0x1e4) from [<c0044340>] (task_work_run+0xac/0xe8)
[<c0044340>] (task_work_run+0xac/0xe8) from [<c002e36c>] (do_exit+0x6bc/0x8d8)
[<c002e36c>] (do_exit+0x6bc/0x8d8) from [<c002e674>] (do_group_exit+0x3c/0xb0)
[<c002e674>] (do_group_exit+0x3c/0xb0) from [<c002e6f8>] (__wake_up_parent+0x0/0x18)

I believe this is due to an attempt to access utsname()->nodename, after
exit_task_namespaces() has been called, leaving current->nsproxy->uts_ns
as NULL and causing the above dereference.

A similar issue was fixed for lockd in 9a1b6bf8 ("LOCKD: Don't call
utsname()->nodename from nlmclnt_setlockargs"), so this patch attempts
something similar for 9pfs.

Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@sandia.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This driver adds an attribute to the existing virtio device so a CHANGE
event is required in order udev rules to make use of it. The ADD event
happens before this driver is probed and unlike a more typical driver
like a block device there isn't a higher level device to watch for.
Signed-off-by: NMichael Marineau <michael.marineau@coreos.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

This patch reverts commit

80b45261

which was implementing a 'cancelled' functionality to notify that
a cancelled request will not be replied.

This implementation was not used anywhere and therefore removed.
Signed-off-by: NAndi Shyti <andi@etezian.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch gets rid of the following warning:

net/9p/trans_rdma.c:594:12: warning: ‘rdma_cancelled’ defined but not used [-Wunused-function]
 static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req)

The rdma_cancelled function is not called anywhere in the kernel
Signed-off-by: NAndi Shyti <andi@etezian.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

p9_release_pages() would attempt to dereference one value past the end of
pages[]. This would cause the following crashes:

[ 6293.171817] BUG: unable to handle kernel paging request at ffff8807c96f3000
[ 6293.174146] IP: [<ffffffff8412793b>] p9_release_pages+0x3b/0x60
[ 6293.176447] PGD 79c5067 PUD 82c1e3067 PMD 82c197067 PTE 80000007c96f3060
[ 6293.180060] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 6293.180060] Modules linked in:
[ 6293.180060] CPU: 62 PID: 174043 Comm: modprobe Tainted: G        W    3.10.0-next-20130710-sasha #3954
[ 6293.180060] task: ffff8807b803b000 ti: ffff880787dde000 task.ti: ffff880787dde000
[ 6293.180060] RIP: 0010:[<ffffffff8412793b>]  [<ffffffff8412793b>] p9_release_pages+0x3b/0x60
[ 6293.214316] RSP: 0000:ffff880787ddfc28  EFLAGS: 00010202
[ 6293.214316] RAX: 0000000000000001 RBX: ffff8807c96f2ff8 RCX: 0000000000000000
[ 6293.222017] RDX: ffff8807b803b000 RSI: 0000000000000001 RDI: ffffea001c7e3d40
[ 6293.222017] RBP: ffff880787ddfc48 R08: 0000000000000000 R09: 0000000000000000
[ 6293.222017] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
[ 6293.222017] R13: 0000000000000001 R14: ffff8807cc50c070 R15: ffff8807cc50c070
[ 6293.222017] FS:  00007f572641d700(0000) GS:ffff8807f3600000(0000) knlGS:0000000000000000
[ 6293.256784] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 6293.256784] CR2: ffff8807c96f3000 CR3: 00000007c8e81000 CR4: 00000000000006e0
[ 6293.256784] Stack:
[ 6293.256784]  ffff880787ddfcc8 ffff880787ddfcc8 0000000000000000 ffff880787ddfcc8
[ 6293.256784]  ffff880787ddfd48 ffffffff84128be8 ffff880700000002 0000000000000001
[ 6293.256784]  ffff8807b803b000 ffff880787ddfce0 0000100000000000 0000000000000000
[ 6293.256784] Call Trace:
[ 6293.256784]  [<ffffffff84128be8>] p9_virtio_zc_request+0x598/0x630
[ 6293.256784]  [<ffffffff8115c610>] ? wake_up_bit+0x40/0x40
[ 6293.256784]  [<ffffffff841209b1>] p9_client_zc_rpc+0x111/0x3a0
[ 6293.256784]  [<ffffffff81174b78>] ? sched_clock_cpu+0x108/0x120
[ 6293.256784]  [<ffffffff84122a21>] p9_client_read+0xe1/0x2c0
[ 6293.256784]  [<ffffffff81708a90>] v9fs_file_read+0x90/0xc0
[ 6293.256784]  [<ffffffff812bd073>] vfs_read+0xc3/0x130
[ 6293.256784]  [<ffffffff811a78bd>] ? trace_hardirqs_on+0xd/0x10
[ 6293.256784]  [<ffffffff812bd5a2>] SyS_read+0x62/0xa0
[ 6293.256784]  [<ffffffff841a1a00>] tracesys+0xdd/0xe2
[ 6293.256784] Code: 66 90 48 89 fb 41 89 f5 48 8b 3f 48 85 ff 74 29 85 f6 74 25 45 31 e4 66 0f 1f 84 00 00 00 00 00 e8 eb 14 12 fd 41 ff c4 49 63 c4 <48> 8b 3c c3 48 85 ff 74 05 45 39 e5 75 e7 48 83 c4 08 5b 41 5c
[ 6293.256784] RIP  [<ffffffff8412793b>] p9_release_pages+0x3b/0x60
[ 6293.256784]  RSP <ffff880787ddfc28>
[ 6293.256784] CR2: ffff8807c96f3000
[ 6293.256784] ---[ end trace 50822ee72cd360fc ]---
Signed-off-by: NSasha Levin <sasha.levin@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RDMA needs to post a buffer for each incoming reply.
Hence it needs to keep count of these and needs to be
aware of whether a flushed request has received a reply
or not.

This patch adds the cancelled() callback to the transport modules.
It is called when RFLUSH has been received and that the corresponding
request will never receive a reply.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

In rdma_request():

If an error occurs between posting the recv and the send,
there will be a reply context posted without a pending
request.
Since there is no way to "un-post" it, we remember it and
skip post_recv() for the next request.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Most importantly:
- do not free the recv context (rpl_context) after a successful post_recv()
- but do free the send context (c) after a failed send.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

rdma_request() should never be in charge of freeing rc.

When an error occurs:
* Either the rc buffer has been recv_post()'ed.
  then kfree()'ing it certainly is a bad idea.
* Or is has not, and in that case req->rc still points to it,
  hence it needs not be freed.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The current code keeps track of the number of buffers posted in the RQ,
and will prevent it from overflowing. But it does so by simply dropping
post requests (And leaking memory in the process).
When this happens there will actually be too few buffers posted, and
soon the 9P server will complain about 'RNR retry counter exceeded'
errors.

Instead, use a semaphore, and block until the RQ is ready for another
buffer to be posted.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

A well-behaved server would not send twice the reply to a request.
But if it ever happens...
This additional check prevents the kernel from leaking memory
and possibly more nasty consequences in that unlikely event.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The current value is too low to get good performance.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

p9_tag_alloc() takes care of that.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

The current code assumes that when a request in the request array
does have a tc, it also has a rc.

This is normally true, but not always : when using RDMA, req->rc
will temporarily be set to NULL after the request has been sent.
That is usually OK though, as when the reply arrives, req->rc will be
reassigned to a sane value before the request is recycled.

But there is a catch : if the request is flushed, the reply will never
arrive, and req->rc will be NULL, but not req->tc.

This patch fixes p9_tag_alloc to take this into account.
Signed-off-by: NSimon Derr <simon.derr@bull.net>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

If the privport option is specified, the tcp transport binds local
address to a reserved port before connecting to the 9p server.

In some cases when 9P AUTH cannot be implemented, this is better than
nothing.
Signed-off-by: NJim Garlick <garlick@llnl.gov>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

For zero copy request, error will be encoded in the user space buffer.
So copy the error code correctly using copy_from_user. Here we use the
extra bytes we allocate for zero copy request. If total error details
are more than P9_ZC_HDR_SZ - 7 bytes, we return -EFAULT. The patch also
avoid a memory allocation in the error path.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

For zero copy request, error will be encoded in the user space buffer.
So copy the error code correctly using copy_from_user. Here we use the
extra bytes we allocate for zero copy request. If total error details
are more than P9_ZC_HDR_SZ - 7 bytes, we return -EFAULT. The patch also
avoid a memory allocation in the error path.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

Make the default 9p experience better by defaulting to virtio transport if present.
These days most of the users are using 9p in a virtualized setup
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

If we dont' specify a protocol version default to 9P2000.L. 9P2000.L
have better support for posix semantic and is where all the recent development
is happening.
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>

virtio_add_buf() is going away, replaced with virtio_add_sgs() which
takes multiple terminated scatterlists.

Cc: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>