The 'mutex' in struct w1_master is use for two very different
purposes.
Firstly it protects various data structures such as the list of all
slaves.
Secondly it protects the w1 buss against concurrent accesses.
This can lead to deadlocks when the ->probe code called while adding a
slave needs to talk on the bus, as is the case for power_supply
devices.
ds2780 and ds2781 drivers contain a work around to track which
process hold the lock simply to avoid this deadlock. bq27000 doesn't
have that work around and so deadlocks.
There are other possible deadlocks involving sysfs.
When removing a device the sysfs s_active lock is held, so the lock
that protects the slave list must take precedence over s_active.
However when access power_supply attributes via sysfs, the s_active
lock must take precedence over the lock that protects accesses to
the bus.
So to avoid deadlocks between w1 slaves and sysfs, these must be
two separate locks. Making them separate means that the work around
in ds2780 and ds2781 can be removed.
So this patch:
- adds a new mutex: "bus_mutex" which serialises access to the bus.
- takes in mutex in w1_search and ds1wm_search while they access
the bus for searching. The mutex is dropped before calling the
callback which adds the slave.
- changes all slaves to use bus_mutex instead of mutex to
protect access to the bus
- removes w1_ds2790_io_nolock and w1_ds2781_io_nolock, and the
related code from drivers/power/ds278[01]_battery.c which
calls them.
Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 59d4467be4.
Turns out it was the wrong version, will apply the correct version after
this.
Reported-by: NeilBrown <neilb@suse.de>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There were some return statements around in the w1_uevent, used goto
to cleanup those return statements with the help of err variable,
and also removed a semi colon at the end of the w1_uevent's closing
brace.
Signed-off-by: Devendra Naga <devendra.aaru@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
w1 devices need a mutex to serial IO. Most use master->mutex.
However that is used for other purposes and they can conflict.
In particular master->mutex is held while w1_attach_slave_device is
called.
For bq27000, this registers a 'powersupply' device which tries to read the
current status. The attempt to read will cause a deadlock on
master->mutex.
So create a new per-slave mutex and use that for serializing IO for
bq27000.
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This enables a much more efficient way of device searching. It uses the
1-wire read-rom operation which allows the direct reading of the slave
address. BUT this works only with exactly one slave on the bus.
Signed-off-by: Hubert Feurstein <h.feurstein@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
index c374978..9761950 100644
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This allows us to move duplicated code in <asm/atomic.h>
(atomic_inc_not_zero() for now) to <linux/atomic.h>
Signed-off-by: Arun Sharma <asharma@fb.com>
Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reorganize so the netlink connector one wire search command will update
the kernel list of detected slave devices. Otherwise, a newly detected
device is unusable because unless it's in the kernel list of known devices
any commands will result in ENODEV status.
Signed-off-by: David Fries <David@Fries.net>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The search/pullup/add/remove device attributes were 0666 which would allow
arbitrary users to affect the 1 wire bus. Change to 0664 to prevent that.
I found this patch in the Android tree, apparently this has never been
sent upstream so doing it now.
Signed-off-by: Brian Swetland <swetland@google.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This allows bin_attr->read,write,mmap callbacks to check file specific data
(such as inode owner) as part of any privilege validation.
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Trivial patch which adds the __init/__exit macros to the module_init/
module_exit functions of
drivers/w1/w1.c
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Fix bug reading the id sysfs file. If less than the full 8 bytes were
read, the next read would start at the first byte instead of continuing.
It needed the offset added to memcpy, or the better solution was to
replace it with the device attribute instead of bin attribute.
Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Simplified the logic in w1_slave_found by using the new
w1_attach_slave_device function to find a slave and mark it as active or
add the device if the crc checks.
Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sysfs entries were added to manually add and remove slave devices. This
is useful if the automatic bus searching is disabled, and the device ids
are already known.
[akpm@linux-foundation.org: fix printk types]
Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a strong pullup option to the w1 system. This supplies extra power
for parasite powered devices. There is a w1_master_pullup sysfs entry and
enable_pullup module parameter to enable or disable the strong pullup.
The one wire bus requires at a minimum one wire and ground. The common
wire is used for sending and receiving data as well as supplying power to
devices that are parasite powered of which temperature sensors can be one
example. The bus must be idle and left high while a temperature
conversion is in progress, in addition the normal pullup resister on
larger networks or even higher temperatures might not supply enough power.
The pullup resister can't provide too much pullup current, because
devices need to pull the bus down to write a value. This enables the
strong pullup for supported hardware, which can supply more current when
requested. Unsupported hardware will just delay with the bus high.
The hardware USB 2490 one wire bus master has a bit on some commands which
will enable the strong pullup as soon as the command finishes executing.
To use strong pullup, call the new w1_next_pullup function to register the
duration. The next write command will call set_pullup before sending the
data, and reset the duration to zero once it returns.
Switched from simple_strtol to strict_strtol.
Signed-off-by: David Fries <david@fries.net>
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The w1_process thread's sleeping and termination has been modified.
msleep_interruptible was replaced by schedule_timeout and schedule to
allow for kthread_stop and wake_up_process to interrupt the sleep and the
unbounded sleeping when a bus search is disabled. The W1_MASTER_NEED_EXIT
and flags variable were removed as they were redundant with
kthread_should_stop and kthread_stop. If w1_process is sleeping,
requesting a search will immediately wake it up rather than waiting for
the end of msleep_interruptible previously.
Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move the creation of the w1_process thread to after the device has been
initialized. This way w1_process doesn't have to check to see if it has
been initialized and the bus search can proceed without sleeping. That
also eliminates two checks in the w1_process loop. The sleep now happens
at the end of the loop not the beginning.
Also added a comment for why the atomic_set was 2.
Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Early abort if the master driver or the hardware goes away in the middle
of a bus search operation. The alternative is to spam the print buffer up
to 64*64 times with read errors in the case of USB.
Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
w1_control_thread was removed which would wake up every second and process
newly registered family codes and complete some final cleanup for a
removed master. Those routines were moved to the threads that were
previously requesting those operations. A new function
w1_reconnect_slaves takes care of reconnecting existing slave devices when
a new family code is registered or removed. The removal case was missing
and would cause a deadlock waiting for the family code reference count to
decrease, which will now happen. A problem with registering a family code
was fixed. A slave device would be unattached if it wasn't yet claimed,
then attached at the end of the list, two unclaimed slaves would cause an
infinite loop.
The struct w1_bus_master.search now takes a pointer to the struct
w1_master device to avoid searching for it, which would have caused a
lock ordering deadlock with the removal of w1_control_thread.
Signed-off-by: David Fries <david@fries.net>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remvoe variable which actually is not used (except assigning it a value)
and confusing break out of the family checking loop. Found by Harry Mason.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Harry J Mason <hjm03r@ecs.soton.ac.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Decrement the slave counter only in ->release() callback instead of both
in ->release() and w1 control.
Patch is based on debug work and preliminary patch made by Henri Laakso.
Henri noticed in debug that this counter becomes negative after w1 slave
device is physically removed.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Henri Laakso <henri.laakso@wapice.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This changes the uevent buffer functions to use a struct instead of a
long list of parameters. It does no longer require the caller to do the
proper buffer termination and size accounting, which is currently wrong
in some places. It fixes a known bug where parts of the uevent
environment are overwritten because of wrong index calculations.
Many thanks to Mathieu Desnoyers for finding bugs and improving the
error handling.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Need to null terminate environment. Found by inspection while looking for
similar problems to platform uevent bug
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Transform some calls to kmalloc/memset to a single kzalloc (or kcalloc).
Here is a short excerpt of the semantic patch performing
this transformation:
@@
type T2;
expression x;
identifier f,fld;
expression E;
expression E1,E2;
expression e1,e2,e3,y;
statement S;
@@
x =
- kmalloc
+ kzalloc
(E1,E2)
... when != \(x->fld=E;\|y=f(...,x,...);\|f(...,x,...);\|x=E;\|while(...) S\|for(e1;e2;e3) S\)
- memset((T2)x,0,E1);
@@
expression E1,E2,E3;
@@
- kzalloc(E1 * E2,E3)
+ kcalloc(E1,E2,E3)
[akpm@linux-foundation.org: get kcalloc args the right way around]
Signed-off-by: Yoann Padioleau <padator@wanadoo.fr>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Bryan Wu <bryan.wu@analog.com>
Acked-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Acked-by: Roland Dreier <rolandd@cisco.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Acked-by: Pierre Ossman <drzeus-list@drzeus.cx>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Greg KH <greg@kroah.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves. This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.
It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.
The patch causes all kernel threads to be nonfreezable by default (ie. to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE. It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear. Additionally, it updates documentation to
describe the freezing of tasks more accurately.
[akpm@linux-foundation.org: build fixes]
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Well, first of all, I don't want to change so many files either.
What I do:
Adding a new parameter "struct bin_attribute *" in the
.read/.write methods for the sysfs binary attributes.
In fact, only the four lines change in fs/sysfs/bin.c and
include/linux/sysfs.h do the real work.
But I have to update all the files that use binary attributes
to make them compatible with the new .read and .write methods.
I'm not sure if I missed any. :(
Why I do this:
For a sysfs attribute, we can get a pointer pointing to the
struct attribute in the .show/.store method,
while we can't do this for the binary attributes.
I don't know why this is different, but this does make it not
so handy to use the binary attributes as the regular ones.
So I think this patch is reasonable. :)
Who benefits from it:
The patch that exposes ACPI tables in sysfs
requires such an improvement.
All the table binary attributes share the same .read method.
Parameter "struct bin_attribute *" is used to get
the table signature and instance number which are used to
distinguish different ACPI table binary attributes.
Without this parameter, we need to offer different .read methods
for different ACPI table binary attributes.
This is impossible as there are various ACPI tables on different
platforms, and we don't know what they are until they are loaded.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
sysfs is now completely out of driver/module lifetime game. After
deletion, a sysfs node doesn't access anything outside sysfs proper,
so there's no reason to hold onto the attribute owners. Note that
often the wrong modules were accounted for as owners leading to
accessing removed modules.
This patch kills now unnecessary attribute->owner. Note that with
this change, userland holding a sysfs node does not prevent the
backing module from being unloaded.
For more info regarding lifetime rule cleanup, please read the
following message.
http://article.gmane.org/gmane.linux.kernel/510293
(tweaked by Greg to not delete the field just yet, to make it easier to
merge things properly.)
Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Move process freezing functions from include/linux/sched.h to freezer.h, so
that modifications to the freezer or the kernel configuration don't require
recompiling just about everything.
[akpm@osdl.org: fix ueagle driver]
Signed-off-by: Nigel Cunningham <nigel@suspend2.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
drivers/w1/w1.c:423: warning: long long unsigned int format, __u64 arg (arg 8)
u64 is not, never has been and never will be "unsigned long long"!
While we're there, fix up some code layout - it looks awful in an 80-col
display.
Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Nice cleanup spotted by Adrian Bunk, which was lost due to moving to the
completely new functionality.
Shame-shame-shame on me.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Use mutexes instead of semaphores.
Patch tested on x86_64 and i386 with test bus master driver.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There are three types of messages between w1 core and userspace:
1. Events. They are generated each time new master or slave device found
either due to automatic or requested search.
2. Userspace commands. Includes read/write and search/alarm search comamnds.
3. Replies to userspace commands.
From: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Special file in each w1 slave device's directory called "rw" is created
each time new slave and no appropriate w1 family is registered.
"rw" file supports read and write operations, which allows to perform
almost any kind of operations. Each logical operation is a transaction
in nature, which can contain several (two or one) low-level operations.
Let's see how one can read EEPROM context:
1. one must write control buffer, i.e. buffer containing command byte
and two byte address. At this step bus is reset and appropriate device
is selected using either W1_SKIP_ROM or W1_MATCH_ROM command.
Then provided control buffer is being written to the wire.
2. reading. This will issue reading eeprom response.
It is possible that between 1. and 2. w1 master thread will reset bus for
searching and slave device will be even removed, but in this case 0xff will
be read, since no device was selected.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch removes old-style kernel thread initialization
and changes w1 to use kthread api.
It is based on Christoph Hellwig <hch@lst.de> work.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
You don't know what type a u64 is, hence you cannot print it without a cast.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch contains the following cleanups:
- make needlessly global code static
- declarations for global code belong into header files
- w1.c: #if 0 the unused struct w1_slave_device
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Leave the overloaded "hotplug" word to susbsystems which are handling
real devices. The driver core does not "plug" anything, it just exports
the state to userspace and generates events.
Signed-off-by: Kay Sievers <kay.sievers@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/built-in.o: In function `w1_alloc_dev': undefined reference to `netlink_kernel_create'
drivers/built-in.o: In function `w1_alloc_dev': undefined reference to `sock_release'
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Patch is based on work from Ben Gardner <bgardner@wabtec.com>
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Here is W1 hotplug in addition to netlink notifications.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Do not spam syslog each 10 seconds when there is nothing on the wire.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
