This allows structure annotations for requiring designated initialization
in GCC 5.1.0 and later:
https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html
The structure randomization layout plugin will be using this to help
identify structures that need this form of initialization.
Signed-off-by: Kees Cook <keescook@chromium.org>
The CPU cooling driver uses the cpufreq policy, to get clip_cpus, the
frequency table, etc. Most of the callers of CPU cooling driver's
registration routines have the cpufreq policy with them, but they only
pass the policy->related_cpus cpumask. The __cpufreq_cooling_register()
routine then gets the policy by itself and uses it.
It would be much better if the callers can pass the policy instead
directly. This also fixes a basic design flaw, where the policy can be
freed while the CPU cooling driver is still active.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
There is only one user of cpufreq_cooling_get_level() and that already
has pointer to the cpufreq_cdev structure. It can directly call
get_level() instead and we can get rid of cpufreq_cooling_get_level().
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Some Ethernet drivers will attach/connect to a PHY device before calling
register_netdevice() which is responsible for calling netdev_register_kobject()
which would do the network device's kobject initialization. In such a case,
sysfs_create_link() would return -ENOENT because the network device's kobject
is not ready yet, and we would fail to connect to the PHY device.
In order to keep things simple and symetrical, we just take the success path as
indicative of the ability to access the network device's kobject, and create
the second link if that's the case.
Fixes: 5568363f0c ("net: phy: Create sysfs reciprocal links for attached_dev/phydev")
Reported-by: Woojung Hung <Woojung.Huh@microchip.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Whenever a user changes bonding options, a NETDEV_CHANGEINFODATA
notificatin is generated which results in a rtnelink message to
be sent. While runnig 'ip monitor', we can actually see 2 messages,
one a result of the event, and the other a result of state change
that is generated bo netdev_state_change(). However, this is not
always the case. If bonding changes were done via sysfs or ifenslave
(old ioctl interface), then only 1 message is seen.
This patch removes duplicate messages in the case of using netlink
to configure bonding. It introduceds a separte function that
triggers a netdev event and uses that function in the syfs and ioctl
cases.
This was discovered while auditing all the different envents and
continues the effort of cleaning up duplicated netlink messages.
CC: David Ahern <dsa@cumulusnetworks.com>
CC: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When netdev events happen, a rtnetlink_event() handler will send
messages for every event in it's white list. These messages contain
current information about a particular device, but they do not include
the iformation about which event just happened. So, it is impossible
to tell what just happend for these events.
This patch adds a new extension to RTM_NEWLINK message called IFLA_EVENT
that would have an encoding of event that triggered this
message. This would allow the the message consumer to easily determine
if it needs to perform certain actions.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull tty/serial fixes from Greg KH:
"Here are some serial and tty fixes for 4.12-rc3. They are a bit bigger
than normal, which is why I had them bake in linux-next for a few
weeks and didn't send them to you for -rc2.
They revert a few of the serdev patches from 4.12-rc1, and bring
things back to how they were in 4.11, to try to make things a bit more
stable there. Rob and Johan both agree that this is the way forward,
so this isn't people squabbling over semantics. Other than that, just
a few minor serial driver fixes that people have had problems with.
All of these have been in linux-next for a few weeks with no reported
issues"
* tag 'tty-4.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: altera_uart: call iounmap() at driver remove
serial: imx: ensure UCR3 and UFCR are setup correctly
MAINTAINERS/serial: Change maintainer of jsm driver
serial: enable serdev support
tty/serdev: add serdev registration interface
serdev: Restore serdev_device_write_buf for atomic context
serial: core: fix crash in uart_suspend_port
tty: fix port buffer locking
tty: ehv_bytechan: clean up init error handling
serial: ifx6x60: fix use-after-free on module unload
serial: altera_jtaguart: adding iounmap()
serial: exar: Fix stuck MSIs
serial: efm32: Fix parity management in 'efm32_uart_console_get_options()'
serdev: fix tty-port client deregistration
Revert "tty_port: register tty ports with serdev bus"
drivers/tty: 8250: only call fintek_8250_probe when doing port I/O
This will make it easier to implement a sane compat fcntl syscall.
[ jlayton: fix undeclared identifiers in 32-bit fcntl64 syscall handler ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
There are no more modular users providing a posix clock. The register
function is now pointless so the posix clock array can be initialized
statically at compile time and the array including the various k_clock
structs can be marked 'const'.
Inspired by changes in the Grsecurity patch set, but done proper.
[ tglx: Massaged changelog and fixed the POSIX_TIMER=n case ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Link: http://lkml.kernel.org/r/20170526090311.3377-3-hch@lst.de
Overlapping changes in drivers/net/phy/marvell.c, bug fix in 'net'
restricting a HW workaround alongside cleanups in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull networking fixes from David Miller:
1) Fix state pruning in bpf verifier wrt. alignment, from Daniel
Borkmann.
2) Handle non-linear SKBs properly in SCTP ICMP parsing, from Davide
Caratti.
3) Fix bit field definitions for rss_hash_type of descriptors in mlx5
driver, from Jesper Brouer.
4) Defer slave->link updates until bonding is ready to do a full commit
to the new settings, from Nithin Sujir.
5) Properly reference count ipv4 FIB metrics to avoid use after free
situations, from Eric Dumazet and several others including Cong Wang
and Julian Anastasov.
6) Fix races in llc_ui_bind(), from Lin Zhang.
7) Fix regression of ESP UDP encapsulation for TCP packets, from
Steffen Klassert.
8) Fix mdio-octeon driver Kconfig deps, from Randy Dunlap.
9) Fix regression in setting DSCP on ipv6/GRE encapsulation, from Peter
Dawson.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (43 commits)
ipv4: add reference counting to metrics
net: ethernet: ax88796: don't call free_irq without request_irq first
ip6_tunnel, ip6_gre: fix setting of DSCP on encapsulated packets
sctp: fix ICMP processing if skb is non-linear
net: llc: add lock_sock in llc_ui_bind to avoid a race condition
bonding: Don't update slave->link until ready to commit
test_bpf: Add a couple of tests for BPF_JSGE.
bpf: add various verifier test cases
bpf: fix wrong exposure of map_flags into fdinfo for lpm
bpf: add bpf_clone_redirect to bpf_helper_changes_pkt_data
bpf: properly reset caller saved regs after helper call and ld_abs/ind
bpf: fix incorrect pruning decision when alignment must be tracked
arp: fixed -Wuninitialized compiler warning
tcp: avoid fastopen API to be used on AF_UNSPEC
net: move somaxconn init from sysctl code
net: fix potential null pointer dereference
geneve: fix fill_info when using collect_metadata
virtio-net: enable TSO/checksum offloads for Q-in-Q vlans
be2net: Fix offload features for Q-in-Q packets
vlan: Fix tcp checksum offloads in Q-in-Q vlans
...
During enslavement to a bridge, after the CHANGEUPPER is sent, the
multicast enabled state of the bridge isn't propagated down to the
offloading driver unless it's changed.
This patch allows such drivers to query the multicast enabled state from
the bridge, so that they'll be able to correctly configure their flood
tables during port enslavement.
In case multicast is disabled, unregistered multicast packets can be
treated as broadcast and be flooded through all the bridge ports.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It's useful for drivers supporting bridge offload to be able to query
the bridge's VLAN filtering state.
Currently, upon enslavement to a bridge master, the offloading driver
will only learn about the bridge's VLAN filtering state after the bridge
device was already linked with its slave.
Being able to query the bridge's VLAN filtering state allows such
drivers to forbid enslavement in case resource couldn't be allocated for
a VLAN-aware bridge and also choose the correct initialization routine
for the enslaved port, which is dependent on the bridge type.
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Andrey Konovalov reported crashes in ipv4_mtu()
I could reproduce the issue with KASAN kernels, between
10.246.7.151 and 10.246.7.152 :
1) 20 concurrent netperf -t TCP_RR -H 10.246.7.152 -l 1000 &
2) At the same time run following loop :
while :
do
ip ro add 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500
ip ro del 10.246.7.152 dev eth0 src 10.246.7.151 mtu 1500
done
Cong Wang attempted to add back rt->fi in commit
82486aa6f1 ("ipv4: restore rt->fi for reference counting")
but this proved to add some issues that were complex to solve.
Instead, I suggested to add a refcount to the metrics themselves,
being a standalone object (in particular, no reference to other objects)
I tried to make this patch as small as possible to ease its backport,
instead of being super clean. Note that we believe that only ipv4 dst
need to take care of the metric refcount. But if this is wrong,
this patch adds the basic infrastructure to extend this to other
families.
Many thanks to Julian Anastasov for reviewing this patch, and Cong Wang
for his efforts on this problem.
Fixes: 2860583fe8 ("ipv4: Kill rt->fi")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This flag when specified will return matched fib result in
response to a RTM_GETROUTE query.
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A later patch wants access to the fib result on an input route lookup
with the rcu lock held. Refactor ip_route_input_noref pushing the logic
between rcu_read_lock ... rcu_read_unlock into a new helper that takes
the fib_result as an input arg.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
A later patch wants access to the fib result on an output route lookup
with the rcu lock held. Refactor __ip_route_output_key_hash, pushing
the logic between rcu_read_lock ... rcu_read_unlock into a new helper
with the fib_result as an input arg.
To keep the name length under control remove the leading underscores
from the name and add _rcu to the name of the new helper indicating it
is called with the rcu read lock held.
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull block fixes from Jens Axboe:
"A collection of fixes that should go into this series. This contains:
- A set of NVMe fixes, pulled from Christoph. This includes a set of
fixes for the fiber channel bits from James Smart, rdma queue depth
fix from Marta, controller removal fixes from Ming, and some more
APST quirk updates from Andy.
- A blk-mq debugfs fix from Bart, fixing a problem with the
untangling of the sysfs and debugfs blk-mq bits that was added in
this series.
- Error code fix in add_partition() from Dan.
- A small series of fixes for the new blk-throttle code from Shaohua"
* 'for-linus' of git://git.kernel.dk/linux-block: (21 commits)
blk-mq: Only register debugfs attributes for blk-mq queues
nvme: Quirk APST on Intel 600P/P3100 devices
nvme: only setup block integrity if supported by the driver
nvme: replace is_flags field in nvme_ctrl_ops with a flags field
nvme-pci: consistencly use ctrl->device for logging
partitions/msdos: FreeBSD UFS2 file systems are not recognized
block: fix an error code in add_partition()
blk-throttle: force user to configure all settings for io.low
blk-throttle: respect 0 bps/iops settings for io.low
blk-throttle: output some debug info in trace
blk-throttle: add hierarchy support for latency target and idle time
nvme_fc: remove extra controller reference taken on reconnect
nvme_fc: correct nvme status set on abort
nvme_fc: set logging level on resets/deletes
nvme_fc: revise comment on teardown
nvme_fc: Support ctrl_loss_tmo
nvme_fc: get rid of local reconnect_delay
blk-mq: remove blk_mq_abort_requeue_list()
nvme: avoid to use blk_mq_abort_requeue_list()
nvme: use blk_mq_start_hw_queues() in nvme_kill_queues()
...
Pull PCI fixes from Bjorn Helgaas:
- fix PCI_ENDPOINT build error (merged for v4.12)
- fix Switchtec driver (merged for v4.12)
- fix imx6 config read timeouts, fallout from changing to non-postable
reads
- add PM "needs_resume" flag for i915 suspend issue
* tag 'pci-v4.12-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
PCI/PM: Add needs_resume flag to avoid suspend complete optimization
PCI: imx6: Fix config read timeout handling
switchtec: Fix minor bug with partition ID register
switchtec: Use new cdev_device_add() helper function
PCI: endpoint: Make PCI_ENDPOINT depend on HAS_DMA
Pul ceph fixes from Ilya Dryomov:
"A bunch of make W=1 and static checker fixups, a RECONNECT_SEQ
messenger patch from Zheng and Luis' fallocate fix"
* tag 'ceph-for-4.12-rc3' of git://github.com/ceph/ceph-client:
ceph: check that the new inode size is within limits in ceph_fallocate()
libceph: cleanup old messages according to reconnect seq
libceph: NULL deref on crush_decode() error path
libceph: fix error handling in process_one_ticket()
libceph: validate blob_struct_v in process_one_ticket()
libceph: drop version variable from ceph_monmap_decode()
libceph: make ceph_msg_data_advance() return void
libceph: use kbasename() and kill ceph_file_part()
We need to return an error for any call that asks for MSI / MSI-X
vectors only, so that non-trivial fallback logic can work properly.
Also valid dev->irq and use the "correct" errno value based on feedback
from Linus.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Fixes: aff17164 ("PCI: Provide sensible IRQ vector alloc/free routines")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add slave mode support to the MSIOF driver, in both PIO and DMA mode.
For now this only supports the transmission of messages with a size
that is known in advance.
Signed-off-by: Hisashi Nakamura <hisashi.nakamura.ak@renesas.com>
Signed-off-by: Hiromitsu Yamasaki <hiromitsu.yamasaki.ym@renesas.com>
[geert: Timeout handling cleanup, spi core integration, cancellation,
rewording]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Add support for registering SPI slave controllers using the existing SPI
master framework:
- SPI slave controllers must use spi_alloc_slave() instead of
spi_alloc_master(), and should provide an additional callback
"slave_abort" to abort an ongoing SPI transfer request,
- SPI slave controllers are added to a new "spi_slave" device class,
- SPI slave handlers can be bound to the SPI slave device represented
by an SPI slave controller using a DT child node named "slave",
- Alternatively, (un)binding an SPI slave handler to the SPI slave
device represented by an SPI slave controller can be done by
(un)registering the slave device through a sysfs virtual file named
"slave".
From the point of view of an SPI slave protocol handler, an SPI slave
controller looks almost like an ordinary SPI master controller. The only
exception is that a transfer request will block on the remote SPI
master, and may be cancelled using spi_slave_abort().
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
This driver supports direct system clock access on the ancient SGI SN2
IA64 systems, and implement the only non-builtin k_clock instance.
Remove it as any remaining IA64 altix user will be running just as old
distros anyway.
Dimitri Sivanich stated: "Since this is SN2 specific, this can be removed."
Note that this does not affect the never uv_mmtimer driver for x86-based
Altix systems.
[ tglx: Added comment to CLOCK_SGI_CYCLE ]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Travis <mike.travis@hpe.com>
Cc: Dimitri Sivanich <sivanich@hpe.com>
Link: http://lkml.kernel.org/r/20170526090311.3377-2-hch@lst.de
perf, tracing, kprobes and jump_labels have a gazillion of ways to create
dependency lock chains. Some of those involve nested invocations of
get_online_cpus().
The conversion of the hotplug locking to a percpu rwsem requires to avoid
such nested calls. sys_perf_event_open() protects most of the syscall logic
against cpu hotplug. This causes nested calls and lock inversions versus
ftrace and kprobes in various interesting ways.
It's impossible to move the hotplug locking to the outer end of all call
chains in the involved facilities, so the hotplug protection in
sys_perf_event_open() needs to be solved differently.
Introduce 'pmus_mutex' which protects a perf private online cpumask. This
mutex is taken when the mask is updated in the cpu hotplug callbacks and
can be taken in sys_perf_event_open() to protect the swhash setup/teardown
code and when the final judgement about a valid event has to be made.
[ tglx: Produced changelog and fixed the swhash interaction ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: http://lkml.kernel.org/r/20170524081548.930941109@linutronix.de
pci_call_probe() can called recursively when a physcial function is probed
and the probing creates virtual functions, which are populated via
pci_bus_add_device() which in turn can end up calling pci_call_probe()
again.
The code has an interesting way to prevent recursing into the workqueue
code. That's accomplished by a check whether the current task runs already
on the numa node which is associated with the device.
While that works to prevent the recursion into the workqueue code, it's
racy versus normal execution as there is no guarantee that the node does
not vanish after the check.
There is another issue with this code. It dereferences cpumask_of_node()
unconditionally without checking whether the node is available.
Make the detection reliable by:
- Mark a probed device as 'is_probed' in pci_call_probe()
- Check in pci_call_probe for a virtual function. If it's a virtual
function and the associated physical function device is marked
'is_probed' then this is a recursive call, so the call can be invoked in
the calling context.
- Add a check whether the node is online before dereferencing it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-pci@vger.kernel.org
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170524081548.771457199@linutronix.de
Several files are used to construct PCM core module, a.k.a snd-pcm.
Although available APIs are described in 'include/sound/pcm.h', some of
them are not exported as symbols in kernel space. Such APIs are just for
module local usage.
This commit adds module local header file and move some function prototypes
into it so that scopes of them are controlled properly and developers
get no confusion from unavailable symbols.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The indirect-PCM helper codes have an implicit assumption that the
appl_ptr always increases. But the PCM core may deal with the
decrement of appl_ptr via rewind ioctls, and it may screw up the
buffer pointer management.
This patch adds the negative appl_ptr diff in transfer functions and
let returning an error instead of always accepting the appl_ptr
updates. The callers are usually PCM ack callbacks, and they pass the
error to the upper layer accordingly.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This patch adds various verifier test cases:
1) A test case for the pruning issue when tracking alignment
is used.
2) Various PTR_TO_MAP_VALUE_OR_NULL tests to make sure pointer
arithmetic turns such register into UNKNOWN_VALUE type.
3) Test cases for the special treatment of LD_ABS/LD_IND to
make sure verifier doesn't break calling convention here.
Latter is needed, since f.e. arm64 JIT uses r1 - r5 for
storing temporary data, so they really must be marked as
NOT_INIT.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Johan Hedberg says:
====================
pull request: bluetooth-next 2017-05-23
Here's the first Bluetooth & 802.15.4 pull request targeting the 4.13
kernel release.
- Bluetooth 5.0 improvements (Data Length Extensions and alternate PHY)
- Support for new Intel Bluetooth adapter [[8087:0aaa]
- Various fixes to ieee802154 code
- Various fixes to HCI UART code
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
sysfs_get_dirent is usually invoked with a string literal, which
have the type char[]. While the toplevel Makefile
disables -Wpointer-sign, other Makefiles like
arch/x86/boot/compressed/Makefile
redefine KBUILD_CFLAGS. Fixes the warning:
In file included from arch/x86/boot/compressed/kaslr.c:17:
In file included from ./include/linux/module.h:17:
In file included from ./include/linux/kobject.h:21:
./include/linux/sysfs.h:517:37: warning: passing 'const unsigned char *'
to parameter of
type 'const char *' converts between pointers to integer types
with different sign
[-Wpointer-sign]
return kernfs_find_and_get(parent, name);
^~~~
./include/linux/kernfs.h:462:57: note: passing argument to parameter
'name' here
kernfs_find_and_get(struct kernfs_node *kn, const char *name)
^
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch makes it possible to pass additional arguments in addition
to uevent action name when writing /sys/.../uevent attribute. These
additional arguments are then inserted into generated synthetic uevent
as additional environment variables.
Before, we were not able to pass any additional uevent environment
variables for synthetic uevents. This made it hard to identify such uevents
properly in userspace to make proper distinction between genuine uevents
originating from kernel and synthetic uevents triggered from userspace.
Also, it was not possible to pass any additional information which would
make it possible to optimize and change the way the synthetic uevents are
processed back in userspace based on the originating environment of the
triggering action in userspace. With the extra additional variables, we are
able to pass through this extra information needed and also it makes it
possible to synchronize with such synthetic uevents as they can be clearly
identified back in userspace.
The format for writing the uevent attribute is following:
ACTION [UUID [KEY=VALUE ...]
There's no change in how "ACTION" is recognized - it stays the same
("add", "change", "remove"). The "ACTION" is the only argument required
to generate synthetic uevent, the rest of arguments, that this patch
adds support for, are optional.
The "UUID" is considered as transaction identifier so it's possible to
use the same UUID value for one or more synthetic uevents in which case
we logically group these uevents together for any userspace listeners.
The "UUID" is expected to be in "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
format where "x" is a hex digit. The value appears in uevent as
"SYNTH_UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" environment variable.
The "KEY=VALUE" pairs can contain alphanumeric characters only. It's
possible to define zero or more more pairs - each pair is then delimited
by a space character " ". Each pair appears in synthetic uevents as
"SYNTH_ARG_KEY=VALUE" environment variable. That means the KEY name gains
"SYNTH_ARG_" prefix to avoid possible collisions with existing variables.
To pass the "KEY=VALUE" pairs, it's also required to pass in the "UUID"
part for the synthetic uevent first.
If "UUID" is not passed in, the generated synthetic uevent gains
"SYNTH_UUID=0" environment variable automatically so it's possible to
identify this situation in userspace when reading generated uevent and so
we can still make a difference between genuine and synthetic uevents.
Signed-off-by: Peter Rajnoha <prajnoha@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
