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130 Commits

Author SHA1 Message Date
Linus Torvalds b7dfde956d Some nice cleanups, and even a patch my wife did as a "live" demo for
Latinoware 2012.
 
 There's a slightly non-trivial merge in virtio-net, as we cleaned up the
 virtio add_buf interface while DaveM accepted the mq virtio-net patches.
 
 You can see my solution in my pending-rebases branch, if that helps, but I
 know you love merging:
 
 https://git.kernel.org/?p=linux/kernel/git/rusty/linux.git;a=commit;h=12e4e64fa66a4c812e4855de32abdb4d819526fe
 
 Cheers,
 Rusty.
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Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull virtio update from Rusty Russell:
 "Some nice cleanups, and even a patch my wife did as a "live" demo for
  Latinoware 2012.

  There's a slightly non-trivial merge in virtio-net, as we cleaned up
  the virtio add_buf interface while DaveM accepted the mq virtio-net
  patches."

* tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (27 commits)
  virtio_console: Add support for remoteproc serial
  virtio_console: Merge struct buffer_token into struct port_buffer
  virtio: add drv_to_virtio to make code clearly
  virtio: use dev_to_virtio wrapper in virtio
  virtio-mmio: Fix irq parsing in command line parameter
  virtio_console: Free buffers from out-queue upon close
  virtio: Convert dev_printk(KERN_<LEVEL> to dev_<level>(
  virtio_console: Use kmalloc instead of kzalloc
  virtio_console: Free buffer if splice fails
  virtio: tools: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: scsi: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: rpmsg: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: net: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: console: make it clear that virtqueue_add_buf() no longer returns > 0
  virtio: make virtqueue_add_buf() returning 0 on success, not capacity.
  virtio: console: don't rely on virtqueue_add_buf() returning capacity.
  virtio_net: don't rely on virtqueue_add_buf() returning capacity.
  virtio-net: remove unused skb_vnet_hdr->num_sg field
  virtio-net: correct capacity math on ring full
  virtio: move queue_index and num_free fields into core struct virtqueue.
  ...
2012-12-20 08:37:05 -08:00
Sjur Brændeland 1b6370463e virtio_console: Add support for remoteproc serial
Add a simple serial connection driver called
VIRTIO_ID_RPROC_SERIAL (11) for communicating with a
remote processor in an asymmetric multi-processing
configuration.

This implementation reuses the existing virtio_console
implementation, and adds support for DMA allocation
of data buffers and disables use of tty console and
the virtio control queue.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-12-18 15:20:44 +10:30
Sjur Brændeland 276a3e954c virtio_console: Merge struct buffer_token into struct port_buffer
Refactoring the splice functionality by unifying the approach for
sending scatter-lists and regular buffers. This simplifies
buffer handling and reduces code size. Splice will now allocate
a port_buffer and send_buf() and free_buf() can always be used
for any buffer.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-12-18 15:20:44 +10:30
sjur.brandeland@stericsson.com eb34f12b50 virtio_console: Free buffers from out-queue upon close
Free pending output buffers from the virtio out-queue when
host has acknowledged port_close.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (rebased & cut down)
2012-12-18 15:20:41 +10:30
Sjur Brændeland 0127f6855e virtio_console: Use kmalloc instead of kzalloc
Avoid the more cpu expensive kzalloc when allocating buffers.
Originally kzalloc was intended for isolating the guest from
the host by not sending random guest data to the host. But device
isolation is not yet in place so kzalloc is not really needed.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-12-18 15:20:39 +10:30
Sjur Brændeland fe5295374e virtio_console: Free buffer if splice fails
Free the allocated scatter list if send_pages fails in function
port_splice_write.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-12-18 15:20:39 +10:30
Rusty Russell 589575a235 virtio: console: make it clear that virtqueue_add_buf() no longer returns > 0
We simplified virtqueue_add_buf(), make it clear in the callers.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-12-18 15:20:35 +10:30
Amit Shah 49e86f1686 virtio: console: don't rely on virtqueue_add_buf() returning capacity.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-12-18 15:20:34 +10:30
Bill Pemberton 2223cbec33 char: remove use of __devinit
CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Mattia Dongili <malattia@linux.it>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: openipmi-developer@lists.sourceforge.net
Cc: linuxppc-dev@lists.ozlabs.org
Cc: cbe-oss-dev@lists.ozlabs.org
Cc: platform-driver-x86@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-11-21 12:55:19 -08:00
Alexey Khoroshilov 33e1afc3d8 virtio: console: fix error handling in init() function
If register_virtio_driver() fails, virtio-ports class is not destroyed.
The patch adds error handling of register_virtio_driver().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:13 +09:30
Masami Hiramatsu 8ca84a50e5 virtio/console: Allocate scatterlist according to the current pipe size
Allocate scatterlist according to the current pipe size.
This allows splicing bigger buffer if the pipe size has
been changed by fcntl.

Changes in v2:
 - Just a minor fix for avoiding a confliction with previous patch.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:12 +09:30
Masami Hiramatsu efe75d24a6 virtio/console: Wait until the port is ready on splice
Wait if the port is not connected or full on splice
like as write is doing.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:12 +09:30
Masami Hiramatsu ec8fc87015 virtio/console: Add a failback for unstealable pipe buffer
Add a failback memcpy path for unstealable pipe buffer.
If buf->ops->steal() fails, virtio-serial tries to
copy the page contents to an allocated page, instead
of just failing splice().

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:12 +09:30
Masami Hiramatsu eb5e89fc70 virtio/console: Add splice_write support
Enable to use splice_write from pipe to virtio-console port.
This steals pages from pipe and directly send it to host.

Note that this may accelerate only the guest to host path.

Changes in v2:
 - Use GFP_KERNEL instead of GFP_ATOMIC in syscall context function.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-28 15:05:12 +09:30
Amit Shah fa8b66ccd2 virtio: console: tell host of open ports after resume from s3/s4
If a port was open before going into one of the sleep states, the port
can continue normal operation after restore.  However, the host has to
be told that the guest side of the connection is open to restore
pre-suspend state.

This wasn't noticed so far due to a bug in qemu that was fixed recently
(which marked the guest-side connection as always open).

CC: stable@vger.kernel.org   # Only for 3.3

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2012-05-17 12:14:33 +03:00
Stephen Boyd 234e340582 simple_open: automatically convert to simple_open()
Many users of debugfs copy the implementation of default_open() when
they want to support a custom read/write function op.  This leads to a
proliferation of the default_open() implementation across the entire
tree.

Now that the common implementation has been consolidated into libfs we
can replace all the users of this function with simple_open().

This replacement was done with the following semantic patch:

<smpl>
@ open @
identifier open_f != simple_open;
identifier i, f;
@@
-int open_f(struct inode *i, struct file *f)
-{
(
-if (i->i_private)
-f->private_data = i->i_private;
|
-f->private_data = i->i_private;
)
-return 0;
-}

@ has_open depends on open @
identifier fops;
identifier open.open_f;
@@
struct file_operations fops = {
...
-.open = open_f,
+.open = simple_open,
...
};
</smpl>

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-05 15:25:50 -07:00
Amit Shah c743d09dbd virtio: console: Disable callbacks for virtqueues at start of S4 freeze
To ensure we don't receive any more interrupts from the host after we
enter the freeze function, disable all vq interrupts.

There wasn't any problem seen due to this in tests, but applying this
patch makes the freeze case more robust.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:45 +10:30
Amit Shah 2b8f41d846 virtio: console: Add freeze and restore handlers to support S4
Remove all vqs and associated buffers in the freeze callback which
prepares us to go into hibernation state.  On restore, re-create all the
vqs and populate the input vqs with buffers to get to the pre-hibernate
state.

Note: Any outstanding unconsumed buffers are discarded; which means
there's a possibility of data loss in case the host or the guest didn't
consume any data already present in the vqs.  This can be addressed in a
later patch series, perhaps in virtio common code.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:45 +10:30
Amit Shah a0e2dbfc22 virtio: console: Move vq and vq buf removal into separate functions
This common code will be shared with the PM freeze function.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-01-12 15:44:45 +10:30
Rusty Russell f96fde41f7 virtio: rename virtqueue_add_buf_gfp to virtqueue_add_buf
Remove wrapper functions. This makes the allocation type explicit in
all callers; I used GPF_KERNEL where it seemed obvious, left it at
GFP_ATOMIC otherwise.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2012-01-12 15:44:42 +10:30
Linus Torvalds 32aaeffbd4 Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
  Revert "tracing: Include module.h in define_trace.h"
  irq: don't put module.h into irq.h for tracking irqgen modules.
  bluetooth: macroize two small inlines to avoid module.h
  ip_vs.h: fix implicit use of module_get/module_put from module.h
  nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
  include: replace linux/module.h with "struct module" wherever possible
  include: convert various register fcns to macros to avoid include chaining
  crypto.h: remove unused crypto_tfm_alg_modname() inline
  uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
  pm_runtime.h: explicitly requires notifier.h
  linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
  miscdevice.h: fix up implicit use of lists and types
  stop_machine.h: fix implicit use of smp.h for smp_processor_id
  of: fix implicit use of errno.h in include/linux/of.h
  of_platform.h: delete needless include <linux/module.h>
  acpi: remove module.h include from platform/aclinux.h
  miscdevice.h: delete unnecessary inclusion of module.h
  device_cgroup.h: delete needless include <linux/module.h>
  net: sch_generic remove redundant use of <linux/module.h>
  net: inet_timewait_sock doesnt need <linux/module.h>
  ...

Fix up trivial conflicts (other header files, and  removal of the ab3550 mfd driver) in
 - drivers/media/dvb/frontends/dibx000_common.c
 - drivers/media/video/{mt9m111.c,ov6650.c}
 - drivers/mfd/ab3550-core.c
 - include/linux/dmaengine.h
2011-11-06 19:44:47 -08:00
Christian Borntraeger 5e38483b35 virtio: console: wait for first console port for early console output
On s390 I have seen some random

"Warning: unable to open an initial console"

boot failure. Turns out that tty_open fails, because the
hvc_alloc was not yet done. In former times this could not happen,
since the probe function automatically called hvc_alloc. With newer
versions (multiport) some host<->guest interaction is required
before hvc_alloc is called. This might be too late, especially if
an initramfs is involved. Lets use a completion if we have
multiport and an early console.

[Amit:
  * Use NULL instead of 0 for pointer comparison
  * Rename 'port_added' to 'early_console_added'
  * Re-format, re-word commit message
  * Rebase patch on top of current queue]

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Acked-by: Chrstian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:41:01 +10:30
Amit Shah 17e5b4f20a virtio: console: add port stats for bytes received, sent and discarded
This commit adds port-specific stats for the number of bytes received,
sent and discarded.  They're exposed via the debugfs interface.  This
data can be used to check for data loss bugs (or disprove such claims).
It can also be used for accounting, if there's such a need.

The stats remain valid throughout the lifetime of the port.  Unplugging
a port will reset the stats.  The numbers are not reset across port
opens/closes.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:41:01 +10:30
Amit Shah 2d24cdaa6e virtio: console: make discard_port_data() use get_inbuf()
discard_port_data() used virtqueue_get_buf() directly instead of using
get_inbuf().  Fix this, so that we get accounting for all received
bytes.  This also simplifies the code a lot.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:41:00 +10:30
Amit Shah ce072a0cee virtio: console: rename variable
'ret' is a misnomer in discard_port_data() since we don't return the
value.  Rename it to 'err'.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:41:00 +10:30
Amit Shah d25a9ddae9 virtio: console: make get_inbuf() return port->inbuf if present
Instead of pulling in a buffer from the vq each time it's called,
get_inbuf() now checks if the current active buffer, in port->inbuf is
valid.  If it is, just returns a pointer to it.  This ends up
simplifying a lot of code calling get_inbuf() since the check for
port->inbuf being valid was done by all the callers.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:41:00 +10:30
Amit Shah defde66996 virtio: console: Fix return type for get_inbuf()
get_inbuf() returns void *.  There's no reason to return void pointers
instead of the correct struct port_buffer *.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:41:00 +10:30
Amit Shah a08fa92d16 virtio: console: Use wait_event_freezable instead of _interruptible
Get ready to support suspend/resume by using the freezable calls so that
blocking read/write syscalls are handled properly across suspend/resume.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:41:00 +10:30
Amit Shah 291024ef35 virtio: console: Ignore port name update request if name already set
We don't allow port name changes dynamically for a port.  So any
requests by the host to change the name are ignored.

Before this patch, if the hypervisor sent a port name while we had one
set already, we would leak memory equivalent to the size of the old
name.

This scenario wasn't expected so far, but with the suspend-resume
support, we'll send the VIRTIO_CONSOLE_PORT_READY message after restore,
which can get us into this situation.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:40:59 +10:30
Amit Shah 286f9a226f virtio: console: Fix indentation
Convert spaces to tabs and fix indentation for an if statement split
into multiple lines.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:40:59 +10:30
Sasha Levin 51c6d61ac5 virtio-console: Use virtio_config_val() for retrieving config
This patch modifies virtio-console to use virtio_config_val() instead
of a 'if(virtio_has_feature()) vdev->config->get()' construct to retrieve
optional values from the config space.

Cc: Amit Shah <amit.shah@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-11-02 11:40:58 +10:30
Paul Gortmaker c22405c98d drivers/char: Add module.h to those who were using it implicitly
A pending cleanup will mean that module.h won't be implicitly
everywhere anymore.  Make sure the modular drivers in char are
actually calling out for <module.h> explicitly in advance.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 19:31:40 -04:00
Rusty Russell 177dbd9563 virtio console: don't manually set or finalize VIRTIO_CONSOLE_F_MULTIPORT.
That's already been done by the virtio infrastructure before the probe
function is called.

Reported-by: alexey.kardashevskiy@au1.ibm.com
Acked-by: Amit Shah <amit.shah@redhat.com>
Tested-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-05-30 11:14:13 +09:30
Amit Shah afa2689e19 virtio: console: Enable call to hvc_remove() on console port remove
This call was disabled as hot-unplugging one virtconsole port led to
another virtconsole port freezing.

Upon testing it again, this now works, so enable it.

In addition, a bug was found in qemu wherein removing a port of one type
caused the guest output from another port to stop working.  I doubt it
was just this bug that caused it (since disabling the hvc_remove() call
did allow other ports to continue working), but since it's all solved
now, we're fine with hot-unplugging of virtconsole ports.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-04-21 22:57:00 +09:30
Amit Shah d7a62cd033 virtio: console: Don't access vqs if device was unplugged
If a virtio-console device gets unplugged while a port is open, a
subsequent close() call on the port accesses vqs to free up buffers.
This can lead to a crash.

The buffers are already freed up as a result of the call to
unplug_ports() from virtcons_remove().  The fix is to simply not access
vq information if port->portdev is NULL.

Reported-by: juzhang <juzhang@redhat.com>
CC: stable@kernel.org
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-06 10:44:13 -08:00
Linus Torvalds ce86d35d2f Merge branch 'tty-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6
* 'tty-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6:
  serial: bfin_5xx: split uart RX lock from uart port lock to avoid deadlock
  68360serial: Plumb in rs_360_get_icount()
  n_gsm: copy mtu over when configuring via ioctl interface
  virtio: console: Move file back to drivers/char/
2011-02-10 12:19:58 -08:00
Amit Shah 51df0acc3d virtio: console: Move file back to drivers/char/
Commit 728674a7e4 moved virtio_console.c
to drivers/tty/hvc/ under the perception of this being an hvc driver.
It was such once, but these days it has generic communication
capabilities as well, so move it to drivers/char/.

In the future, the hvc part from this file can be split off and moved
under drivers/tty/hvc/.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
CC: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-03 14:43:12 -08:00
Greg Kroah-Hartman 728674a7e4 tty: move hvc drivers to drivers/tty/hvc/
As requested by Arnd Bergmann, the hvc drivers are now
moved to the drivers/tty/hvc/ directory.  The virtio_console.c driver
was also moved, as it required the hvc_console.h file to be able to be
built, and it really is a hvc driver.

Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-13 12:03:00 -08:00
Jiri Slaby 22e132ff26 Char: virtio_console, fix memory leak
Stanse found that in init_vqs, memory is leaked under certain
circumstanses (the fail path order is incorrect). Fix that by checking
allocations in one turn and free all of them at once if some fails
(some may be NULL, but this is OK).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-11-24 15:21:12 +10:30
Amit Shah 299fb61c08 virtio: console: Disable lseek(2) for port file operations
The ports are char devices; do not have seeking capabilities.  Calling
nonseekable_open() from the fops_open() call and setting the llseek fops
pointer to no_llseek ensures an lseek() call from userspace returns
-ESPIPE.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:04 +10:30
Amit Shah a461e11e7b virtio: console: Send SIGIO in case of port unplug
If a port has registered for SIGIO signals, let the application
know that the port is getting unplugged.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:04 +10:30
Amit Shah 55f6bcce36 virtio: console: Send SIGIO on new data arrival on ports
Send a SIGIO signal when new data arrives on a port. This is sent only
when the process has requested for the signal to be sent using fcntl().

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:04 +10:30
Amit Shah 3eae0adea9 virtio: console: Send SIGIO to processes that request it for host events
A process can request for SIGIO on host connect / disconnect events
using the O_ASYNC file flag using fcntl().

If that's requested, and if the guest-side connection for the port is
open, any host-side open/close events for that port will raise a SIGIO.
The process can then use poll() within the signal handler to find out
which port triggered the signal.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:03 +10:30
Amit Shah e062013c7d virtio: console: Reference counting portdev structs is not needed
Explain in a comment why there's no need to reference-count the portdev
struct: when a device is yanked out, we can't do anything more with it
anyway so just give up doing anything more with the data or the vqs and
exit cleanly.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:03 +10:30
Amit Shah b353a6b821 virtio: console: Add reference counting for port struct
When a port got hot-unplugged, when a port was open, any file operation
after the unplugging resulted in a crash. This is fixed by ref-counting
the port structure, and releasing it only when the file is closed.

This splits the unplug operation in two parts: first marks the port
as unavailable, removes all the buffers in the vqs and removes the port
from the per-device list of ports. The second stage, invoked when all
references drop to zero, releases the chardev and frees all other memory.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:03 +10:30
Amit Shah d22a69892b virtio: console: Use cdev_alloc() instead of cdev_init()
This moves to using cdev on the heap instead of it being embedded in the
ports struct. This helps individual refcounting and will allow us to
properly remove cdev structs after hot-unplugs and close operations.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:03 +10:30
Amit Shah 04950cdf07 virtio: console: Add a find_port_by_devt() function
To convert to using cdev as a pointer to avoid kref troubles, we have to
use a different method to get to a port from an inode than the current
container_of method.

Add find_port_by_devt() that looks up all portdevs and ports with those
portdevs to find the right port.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:03 +10:30
Amit Shah 6bdf2afd02 virtio: console: Add a list of portdevs that are active
The virtio_console.c driver is capable of handling multiple devices at a
time. Maintain a list of devices for future traversal.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:02 +10:30
Amit Shah 8ad37e83c8 virtio: console: open: Use a common path for error handling
Just re-arrange code for future patches.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:02 +10:30
Amit Shah 7a2853178d virtio: console: remove_port() should return void
When a port is removed, we have to assume the port is gone. So a
success/failure return value doesn't make sense.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2010-10-21 17:44:02 +10:30