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commit 96f97a83910cdb9d89d127c5ee523f8fc040a804 upstream.
If a port gets unplugged while a user is blocked on read(), -ENODEV is
returned. However, subsequent read()s returned 0, indicating there's no
host-side connection (but not indicating the device went away).
This also happened when a port was unplugged and the user didn't have
any blocking operation pending. If the user didn't monitor the SIGIO
signal, they won't have a chance to find out if the port went away.
Fix by returning -ENODEV on all read()s after the port gets unplugged.
write() already behaves this way.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 92d3453815fbe74d539c86b60dab39ecdf01bb99 upstream.
SIGIO should be sent when a port gets unplugged. It should only be sent
to prcesses that have the port opened, and have asked for SIGIO to be
delivered. We were clearing out guest_connected before calling
send_sigio_to_port(), resulting in a sigio not getting sent to
processes.
Fix by setting guest_connected to false after invoking the sigio
function.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ea3768b4386a8d1790f4cc9a35de4f55b92d6442 upstream.
We used to keep the port's char device structs and the /sys entries
around till the last reference to the port was dropped. This is
actually unnecessary, and resulted in buggy behaviour:
1. Open port in guest
2. Hot-unplug port
3. Hot-plug a port with the same 'name' property as the unplugged one
This resulted in hot-plug being unsuccessful, as a port with the same
name already exists (even though it was unplugged).
This behaviour resulted in a warning message like this one:
-------------------8<---------------------------------------
WARNING: at fs/sysfs/dir.c:512 sysfs_add_one+0xc9/0x130() (Not tainted)
Hardware name: KVM
sysfs: cannot create duplicate filename
'/devices/pci0000:00/0000:00:04.0/virtio0/virtio-ports/vport0p1'
Call Trace:
[<ffffffff8106b607>] ? warn_slowpath_common+0x87/0xc0
[<ffffffff8106b6f6>] ? warn_slowpath_fmt+0x46/0x50
[<ffffffff811f2319>] ? sysfs_add_one+0xc9/0x130
[<ffffffff811f23e8>] ? create_dir+0x68/0xb0
[<ffffffff811f2469>] ? sysfs_create_dir+0x39/0x50
[<ffffffff81273129>] ? kobject_add_internal+0xb9/0x260
[<ffffffff812733d8>] ? kobject_add_varg+0x38/0x60
[<ffffffff812734b4>] ? kobject_add+0x44/0x70
[<ffffffff81349de4>] ? get_device_parent+0xf4/0x1d0
[<ffffffff8134b389>] ? device_add+0xc9/0x650
-------------------8<---------------------------------------
Instead of relying on guest applications to release all references to
the ports, we should go ahead and unregister the port from all the core
layers. Any open/read calls on the port will then just return errors,
and an unplug/plug operation on the host will succeed as expected.
This also caused buggy behaviour in case of the device removal (not just
a port): when the device was removed (which means all ports on that
device are removed automatically as well), the ports with active
users would clean up only when the last references were dropped -- and
it would be too late then to be referencing char device pointers,
resulting in oopses:
-------------------8<---------------------------------------
PID: 6162 TASK: ffff8801147ad500 CPU: 0 COMMAND: "cat"
#0 [ffff88011b9d5a90] machine_kexec at ffffffff8103232b
#1 [ffff88011b9d5af0] crash_kexec at ffffffff810b9322
#2 [ffff88011b9d5bc0] oops_end at ffffffff814f4a50
#3 [ffff88011b9d5bf0] die at ffffffff8100f26b
#4 [ffff88011b9d5c20] do_general_protection at ffffffff814f45e2
#5 [ffff88011b9d5c50] general_protection at ffffffff814f3db5
[exception RIP: strlen+2]
RIP: ffffffff81272ae2 RSP: ffff88011b9d5d00 RFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff880118901c18 RCX: 0000000000000000
RDX: ffff88011799982c RSI: 00000000000000d0 RDI: 3a303030302f3030
RBP: ffff88011b9d5d38 R8: 0000000000000006 R9: ffffffffa0134500
R10: 0000000000001000 R11: 0000000000001000 R12: ffff880117a1cc10
R13: 00000000000000d0 R14: 0000000000000017 R15: ffffffff81aff700
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#6 [ffff88011b9d5d00] kobject_get_path at ffffffff8126dc5d
#7 [ffff88011b9d5d40] kobject_uevent_env at ffffffff8126e551
#8 [ffff88011b9d5dd0] kobject_uevent at ffffffff8126e9eb
#9 [ffff88011b9d5de0] device_del at ffffffff813440c7
-------------------8<---------------------------------------
So clean up when we have all the context, and all that's left to do when
the references to the port have dropped is to free up the port struct
itself.
Reported-by: chayang <chayang@redhat.com>
Reported-by: YOGANANTH SUBRAMANIAN <anantyog@in.ibm.com>
Reported-by: FuXiangChun <xfu@redhat.com>
Reported-by: Qunfang Zhang <qzhang@redhat.com>
Reported-by: Sibiao Luo <sluo@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 671bdea2b9f210566610603ecbb6584c8a201c8c upstream.
Between open() being called and processed, the port can be unplugged.
Check if this happened, and bail out.
A simple test script to reproduce this is:
while true; do for i in $(seq 1 100); do echo $i > /dev/vport0p3; done; done;
This opens and closes the port a lot of times; unplugging the port while
this is happening triggers the bug.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 057b82be3ca3d066478e43b162fc082930a746c9 upstream.
There's a window between find_port_by_devt() returning a port and us
taking a kref on the port, where the port could get unplugged. Fix it
by taking the reference in find_port_by_devt() itself.
Problem reported and analyzed by Mateusz Guzik.
Reported-by: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit aded024a12b32fc1ed9a80639681daae2d07ec25 upstream.
Don't access uninitialized work-queue when removing device.
The work queue is initialized only if the device multi-queue.
So don't call cancel_work unless this is a multi-queue device.
This fixes the following panic:
Kernel panic - not syncing: BUG!
Call Trace:
62031b28: [<6026085d>] panic+0x16b/0x2d3
62031b30: [<6004ef5e>] flush_work+0x0/0x1d7
62031b60: [<602606f2>] panic+0x0/0x2d3
62031b68: [<600333b0>] memcpy+0x0/0x140
62031b80: [<6002d58a>] unblock_signals+0x0/0x84
62031ba0: [<602609c5>] printk+0x0/0xa0
62031bd8: [<60264e51>] __mutex_unlock_slowpath+0x13d/0x148
62031c10: [<6004ef5e>] flush_work+0x0/0x1d7
62031c18: [<60050234>] try_to_grab_pending+0x0/0x17e
62031c38: [<6004e984>] get_work_gcwq+0x71/0x8f
62031c48: [<60050539>] __cancel_work_timer+0x5b/0x115
62031c78: [<628acc85>] unplug_port+0x0/0x191 [virtio_console]
62031c98: [<6005061c>] cancel_work_sync+0x12/0x14
62031ca8: [<628ace96>] virtcons_remove+0x80/0x15c [virtio_console]
62031ce8: [<628191de>] virtio_dev_remove+0x1e/0x7e [virtio]
62031d08: [<601cf242>] __device_release_driver+0x75/0xe4
62031d28: [<601cf2dd>] device_release_driver+0x2c/0x40
62031d48: [<601ce0dd>] driver_unbind+0x7d/0xc6
62031d88: [<601cd5d9>] drv_attr_store+0x27/0x29
62031d98: [<60115f61>] sysfs_write_file+0x100/0x14d
62031df8: [<600b737d>] vfs_write+0xcb/0x184
62031e08: [<600b58b8>] filp_close+0x88/0x94
62031e38: [<600b7686>] sys_write+0x59/0x88
62031e88: [<6001ced1>] handle_syscall+0x5d/0x80
62031ea8: [<60030a74>] userspace+0x405/0x531
62031f08: [<600d32cc>] sys_dup+0x0/0x5e
62031f28: [<601b11d6>] strcpy+0x0/0x18
62031f38: [<600be46c>] do_execve+0x10/0x12
62031f48: [<600184c7>] run_init_process+0x43/0x45
62031fd8: [<60019a91>] new_thread_handler+0xba/0xbc
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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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>
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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;
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-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>
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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>
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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>
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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>
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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>
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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
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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>
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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>
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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>
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'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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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/
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Commit 728674a7e466628df2aeec6d11a2ae1ef968fb67 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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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When a port is hot-unplugged while an app was blocked on a write() call,
the call was unblocked but would not get an error returned.
Return -ENODEV to ensure the app knows the port has gone away.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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When a port is hot-unplugged while an app was blocked on a read() call,
the call was unblocked but would not get an error returned.
Return -ENODEV to ensure the app knows the port has gone away.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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When a port is hot-unplugged while an app is blocked on poll(), unblock
the poll() and return.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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If a chardev is closed, any blocked read / poll calls should just return
and not attempt to use other state.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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A portdev may have been hot-unplugged while a port was open()ed. Skip
sending control messages when the portdev isn't valid.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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If a portdev isn't using multiport support, it won't have any control vq
data to remove.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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The virtqueues should be disabled before attempting to remove the
device.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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If the host is slow in reading data or doesn't read data at all,
blocking write calls not only blocked the program that called write()
but the entire guest itself.
To overcome this, let's not block till the host signals it has given
back the virtio ring element we passed it. Instead, send the buffer to
the host and return to userspace. This operation then becomes similar
to how non-blocking writes work, so let's use the existing code for this
path as well.
This code change also ensures blocking write calls do get blocked if
there's not enough room in the virtio ring as well as they don't return
-EAGAIN to userspace.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
CC: stable@kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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