I finally did as you suggested and added the notifier to the struct
bus_type itself. There are still problems to be expected is something
attaches to a bus type where the code can hook in different struct
device sub-classes (which is imho a big bogosity but I won't even try to
argue that case now) but it will solve nicely a number of issues I've
had so far.

That also means that clients interested in registering for such
notifications have to do it before devices are added and after bus types
are registered. Fortunately, most bus types that matter for the various
usage scenarios I have in mind are registerd at postcore_initcall time,
which means I have a really nice spot at arch_initcall time to add my
notifiers.

There are 4 notifications provided. Device being added (before hooked to
the bus) and removed (failure of previous case or after being unhooked
from the bus), along with driver being bound to a device and about to be
unbound.

The usage I have for these are:

 - The 2 first ones are used to maintain a struct device_ext that is
hooked to struct device.firmware_data. This structure contains for now a
pointer to the Open Firmware node related to the device (if any), the
NUMA node ID (for quick access to it) and the DMA operations pointers &
iommu table instance for DMA to/from this device. For bus types I own
(like IBM VIO or EBUS), I just maintain that structure directly from the
bus code when creating the devices. But for bus types managed by generic
code like PCI or platform (actually, of_platform which is a variation of
platform linked to Open Firmware device-tree), I need this notifier.

 - The other two ones have a completely different usage scenario. I have
cases where multiple devices and their drivers depend on each other. For
example, the IBM EMAC network driver needs to attach to a MAL DMA engine
which is a separate device, and a PHY interface which is also a separate
device. They are all of_platform_device's (well, about to be with my
upcoming patches) but there is no say in what precise order the core
will "probe" them and instanciate the various modules. The solution I
found for that is to have the drivers for emac to use multithread_probe,
and wait for a driver to be bound to the target MAL and PHY control
devices (the device-tree contains reference to the MAL and PHY interface
nodes, which I can then match to of_platform_devices). Right now, I've
been polling, but with that notifier, I can more cleanly wait (with a
timeout of course).
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Eliminate more __must_check madness.

The return code from device_for_each_child() depends on the values
which the helper function returns.  If the helper function always
returns zero, it's utterly pointless to check the return code from
device_for_each_child().

The only code which knows if the return value should be checked is
the caller itself, so forcing the return code to always be checked
is silly.  Hence, remove the __must_check annotation.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There is a potential deadlock in the driver core.  It boils down to
the fact that bus_remove_device() calls klist_remove() instead of
klist_del(), thereby waiting until the reference count of the
klist_node in the bus's klist of devices drops to 0.  The refcount
can't reach 0 so long as a modprobe process is trying to bind a new
driver to the device being removed, by calling __driver_attach().  The
problem is that __driver_attach() tries to acquire the device's
parent's semaphore, but the caller of bus_remove_device() is quite
likely to own that semaphore already.

It isn't sufficient just to replace klist_remove() with klist_del().
Doing so runs the risk that the device would remain on the bus's klist
of devices for some time, and so could be bound to another driver even
after it was unregistered.  What's needed is a new way to distinguish
whether or not a device is registered, based on a criterion other than
whether its klist_node is linked into the bus's klist of devices.  That
way driver binding can fail when the device is unregistered, even if
it is still linked into the klist.

This patch (as782) implements the solution, by adding a new bitflag to
indiate when a struct device is registered, by testing the flag before
allowing a driver to bind a device, and by changing the definition of
the device_is_registered() inline.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This adds the infrastructure for drivers to do a threaded probe, and
waits at init time for all currently outstanding probes to complete.

A new kernel thread will be created when the probe() function for the
driver is called, if the multithread_probe bit is set in the driver
saying it can support this kind of operation.

I have tested this with USB and PCI, and it works, and shaves off a lot
of time in the boot process, but there are issues with finding root boot
disks, and some USB drivers assume that this can never happen, so it is
currently not enabled for any bus type.  Individual drivers can enable
this right now if they wish, and bus authors can selectivly turn it on
as well, once they determine that their subsystem will work properly
with it.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add lots of return-value checking.

<pcornelia.huck@de.ibm.com>: fix bus_rescan_devices()]
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We're getting a lot of crashes in the sysfs/kobject/device/bus/class code and
they're very hard to diagnose.

I'm suspecting that in some cases this is because drivers aren't checking
return values and aren't handling errors correctly.  So the code blithely
blunders on and crashes later in very obscure ways.

There's just no reason to ignore errors which can and do occur.  So the patch
sprinkles __must_check all over these APIs.

Causes 1,513 new warnings.  Heh.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Makes it easier for devices to create and remove binary attribute files
so they don't have to call directly into sysfs.  This is needed to help
with the conversion from struct class_device to struct device.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

When moving class_device usage over to device, we need to handle
class_interfaces properly with devices.  This patch adds that support.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This change creates a devices/virtual/CLASS_NAME tree for struct devices
that belong to a class, yet do not have a "real" struct device for a
parent.  It automatically creates the directories on the fly as needed.


Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The network layer needs this to convert to using struct device instead
of a struct class_device.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This adds two new callbacks to the class structure:
	int	(*dev_uevent)(struct device *dev, char **envp, int num_envp,
			char *buffer, int buffer_size);
	void	(*dev_release)(struct device *dev);

And one pointer:
	struct device_attribute		* dev_attrs;

which all corrispond with the same thing as the "normal" class devices
do, yet this is for when a struct device is bound to a class.

Someday soon, struct class_device will go away, and then the other
fields in this structure can be removed too.  But this is necessary in
order to get the transition to work properly.

Tested out on a network core patch that converted it to use struct
device instead of struct class_device.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This is needed for the network class devices in order to be able to
convert over to use struct device.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Remove the new suspend_prepare() phase.  It doesn't seem very usable,
has never been tested, doesn't address fault cleanup, and would need
a sibling resume_complete(); plus there are no real use cases.  It
could be restored later if those issues get resolved.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Allow devices to participate in the suspend process more intimately,
in particular, allow the final phase (with interrupts disabled) to
also be open to normal devices, not just system devices.

Also, allow classes to participate in device suspend.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Adds const to class_create second parameter, because:

struct class {
	const char * name;

	/*...*/
}
Signed-off-by: NMiguel Ojeda Sandonis <maxextreme@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NDmitry Torokhov <dtor@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as721) makes dev_info and related macros print the device's
bus name if the device doesn't have a driver, instead of printing just a
blank.  If the device isn't on a bus either... well, then it does leave
a blank space.  But it will be easier for someone else to change if they
want.

Cc: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This is the first step in moving class_device to being replaced by
struct device.  It allows struct device to export a dev_t and makes it
easy to dynamically create and destroy struct device as long as they are
associated with a specific class.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Extend the support of attribute groups in class_device's to allow
groups to be created as part of the registration process. This allows
network device's to avoid race between registration and creating
groups.

Note that unlike attributes that are a property of the class object,
the groups are a property of the class_device object. This is done
because there are different types of network devices (wireless for
example).
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Both usb.h and device.h have collections of convenience macros for
printk() with the KERN_ERR, KERN_WARNING, and KERN_NOTICE severity
levels. This patch adds macros for the KERN_NOTICE level which was
so far uncatered for.

These macros already exist privately in drivers/isdn/gigaset/gigaset.h
(currently in the process of being submitted for the kernel tree)
but they really belong with their brothers and sisters in
include/linux/{device,usb}.h.
Signed-off-by: NTilman Schmidt <tilman@imap.cc>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Adding support for exposing hidden raid components for sg
interface. The sdev->no_uld_attach flag will set set accordingly.

The sas module supports adding/removing raid volumes using online
storage management application interface.

This patch was provided to me by Christoph Hellwig.
Signed-off-by: NEric Moore <Eric.Moore@lsil.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NJames Bottomley <James.Bottomley@SteelEye.com>

Add bus_type probe, remove and shutdown methods to replace the
corresponding methods in struct device_driver.  This matches
the way we handle the suspend/resume methods.

Since the bus methods override the device_driver methods, warn
if a device driver is registered whose methods will not be
called.

The long-term idea is to remove the device_driver methods entirely.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NGreg 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: NKay Sievers <kay.sievers@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Convert everyone who uses platform_bus_type to include
linux/platform_device.h.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>

In PM v1, all devices were called at SUSPEND_DISABLE level.  Then
all devices were called at SUSPEND_SAVE_STATE level, and finally
SUSPEND_POWER_DOWN level.  However, with PM v2, to maintain
compatibility for platform devices, I arranged for the PM v2
suspend/resume callbacks to call the old PM v1 suspend/resume
callbacks three times with each level in order so that existing
drivers continued to work.

Since this is obsolete infrastructure which is no longer necessary,
we can remove it.  Here's an (untested) patch to do exactly that.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch allows struct class_device to be nested, so that another
struct class_device can be the parent of a new one, instead of only
having the struct class be the parent.  This will allow us to
(hopefully) fix up the input and video class subsystem mess.

But please people, don't go crazy and start making huge trees of class
devices, you should only need 2 levels deep to get everything to work
(remember to use a class_interface to get notification of a new class
device being added to the system.)

Oh, this also allows us to have the possibility of potentially, someday,
moving /sys/block into /sys/class.  The main hindrance is that pesky
/dev numberspace issue...
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

A "coldplug + udevstart" can be simple like this:
  for i in /sys/block/*/*/uevent; do echo 1 > $i; done
  for i in /sys/class/*/*/uevent; do echo 1 > $i; done
  for i in /sys/bus/*/devices/*/uevent; do echo 1 > $i; done
Signed-off-by: NKay Sievers <kay.sievers@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Driver core: pass interface to class intreface methods

Pass interface as argument to add() and remove() class interface
methods. This way a subsystem can implement generic add/remove
handlers and then call interface-specific ones.
Signed-off-by: NDmitry Torokhov <dtor@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

add the helper and use it instead of open coding the klist_node_attached() check
(which is a layering violation IMHO)

idea by Alan Stern.
Signed-off-by: NDaniel Ritz <daniel.ritz@gmx.ch>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Implement the framework for binding physical devices
with ACPI devices. A physical bus like PCI bus
should create a 'acpi_bus_type', with:

.find_device:
        For device which has parent such as normal PCI devices.

.find_bridge:
        It's for special devices, such as PCI root bridge
	or IDE controller.  Such devices generally haven't a
	parent or ->bus. We use the special method
	to get an ACPI handle.

Uses new field in struct device: firmware_data

http://bugzilla.kernel.org/show_bug.cgi?id=4277Signed-off-by: NDavid Shaohua Li <shaohua.li@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

No one was looking at the return value of bus_rescan_devices, and it
really wasn't anything that anyone in the kernel would ever care about.
So change it which enabled some counting code to be removed also.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add bus_find_device() and driver_find_device() which allow searching for a
device in the bus's resp. the driver's klist and obtain a reference on it.
Signed-off-by: NCornelia Huck <cohuck@de.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch adds the device_attribute paramerter to the
device_attribute store and show sysfs callback functions, and passes a
reference to the attribute when the callbacks are called.
Signed-off-by: NYani Ioannou <yani.ioannou@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

There's no check to see if the device is already bound to a driver, which
could do bad things.  The first thing to go wrong is that it will try to match
a driver with a device already bound to one.  In some cases (it appears with
USB with drivers/usb/core/usb.c::usb_match_id()), some drivers will match a
device based on the class type, so it would be common (especially for HID
devices) to match a device that is already bound.

The fun comes when ->probe() is called, it fails, then
driver_probe_device() does this:

	dev->driver = NULL;

Later on, that pointer could be be dereferenced without checking and cause
hell to break loose.

This problem could be nasty. It's very hardware dependent, since some
devices could have a different set of matching qualifiers than others.

Now, I don't quite see exactly where/how you were getting that crash.
You're dereferencing bad memory, but I'm not sure which pointer was bad
and where it came from, but it could have come from a couple of different
places.

The patch below will hopefully fix it all up for you. It's against
2.6.12-rc2-mm1, and does the following:

- Move logic to driver_probe_device() and comments uncommon returns:
  1 - If device is bound
  0 - If device not bound, and no error
  error - If there was an error.

- Move locking to caller of that function, since we want to lock a
  device for the entire time we're trying to bind it to a driver (to
  prevent against a driver being loaded at the same time).

- Update __device_attach() and __driver_attach() to do that locking.

- Check if device is already bound in __driver_attach()

- Update the converse device_release_driver() so it locks the device
  around all of the operations.

- Mark driver_probe_device() as static and remove export. It's an
  internal function, it should stay that way, and there are no other
  callers. If there is ever a need to export it, we can audit it as
  necessary.
Signed-off-by: NAndrew Morton <akpm@osdl.org>

- Use klist iterator in device_for_each_child(), making it safe to use for
  removing devices.
- Remove unused list_to_dev() function.
- Kills all usage of devices_subsys.rwsem.
Signed-off-by: NPatrick Mochel <mochel@digitalimplant.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>