We've had various reports of some legacy "probe the hardware" style
platform drivers having nasty problems with hotplug support.
The core issue is that those legacy drivers don't fully conform to the
driver model. They assume a role that should be the responsibility of
infrastructure code: creating device nodes.
The "modprobe" step in hotplugging relies on drivers to have split those
roles into different modules. The lack of this split causes the problems.
When a driver creates nodes for devices that don't exist (sending a hotplug
event), then exits (aborting one modprobe) before the "modprobe $MODALIAS"
step completes (by failing, since it's in the middle of a modprobe), the
result can be an endless loop of modprobe invocations ... badness.
This fix uses the newish per-device flag controlling issuance of "add"
events. (A previous version of this patch used a per-device "driver can
hotplug" flag, which only scrubbed $MODALIAS from the environment rather
than suppressing the entire hotplug event.) It also shrinks that flag to
one bit, saving a word in "struct device".
So the net of this patch is removing some nasty failures with legacy
drivers, while retaining hotplug capability for the majority of platform
drivers.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Greg KH <gregkh@suse.de>
Cc: Andres Salomon <dilinger@debian.org>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* master.kernel.org:/pub/scm/linux/kernel/git/gregkh/driver-2.6:
remove "struct subsystem" as it is no longer needed
sysfs: printk format warning
DOC: Fix wrong identifier name in Documentation/driver-model/devres.txt
platform: reorder platform_device_del
Driver core: fix show_uevent from taking up way too much stack
This patch removes the PCI_MULTITHREAD_PROBE option that had already
been marked as broken.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We need to work on cleaning up the relationship between kobjects, ksets and
ktypes. The removal of 'struct subsystem' is the first step of this,
especially as it is not really needed at all.
Thanks to Kay for fixing the bugs in this patch.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Duplicate what Zach Brown did for pr_debug in commit
8b2a1fd1b3
[akpm@linux-foundation.org: fix a couple of things which broke]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as896b) fixes an oversight in the design of
device_schedule_callback(). It is necessary to acquire a reference to the
module owning the callback routine, to prevent the module from being
unloaded before the callback can run.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Satyam Sharma <satyam.sharma@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Driver core: add suspend() and resume() to struct device_type
In cases when there are devices of different types in the same class
we can't use class's implementation of suspend and resume methods and
we need to add them to struct device_type instead.
Also fix error handling in resume code (we should not try to call
class's resume method iof bus's resume method for the device failed.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The completion in the driver release path is due to ancient history in
the _very_ early 2.5 days when we were not tracking the module reference
count of attributes. It is not needed at all and can be removed.
Note, we now have an empty release function for the driver structure.
This is due to the fact that drivers are statically allocated in the
system at this point in time, something which I want to change in the
future. But remember, drivers are really code, which is reference
counted by the module, unlike devices, which are data and _must_ be
reference counted properly in order to work correctly.
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Make multithreaded probing work per subsystem instead of per driver.
It doesn't make much sense to probe the same device for multiple drivers in
parallel (after all, only one driver can bind to the device). Instead, create
a probing thread for each device that probes the drivers one after another.
Also make the decision to use multi-threaded probe per bus instead of per
device and adapt the pci code.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If "name" of a device_type is specified, the uevent will
contain the device_type name in the DEVTYPE variable.
This helps userspace to distingiush between different types
of devices, belonging to the same subsystem.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Driver core: use attribute groups in struct device_type
Attribute groups are more flexible than attribute lists
(an attribute list can be represented by anonymous group)
so switch struct device_type to use them.
Also rework attribute creation for devices so that they all
cleaned up properly in case of errors.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Kay Sievers <kay.sievers@novell.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We get two per-bus sysfs files:
ls-l /sys/subsystem/usb
drwxr-xr-x 2 root root 0 2007-02-16 16:42 devices
drwxr-xr-x 7 root root 0 2007-02-16 14:55 drivers
-rw-r--r-- 1 root root 4096 2007-02-16 16:42 drivers_autoprobe
--w------- 1 root root 4096 2007-02-16 16:42 drivers_probe
The flag "drivers_autoprobe" controls the behavior of the bus to bind
devices by default, or just initialize the device and leave it alone.
The command "drivers_probe" accepts a bus_id and the bus tries to bind a
driver to this device.
Systems who want to control the driver binding with udev, switch off the
bus initiated probing:
echo 0 > /sys/subsystem/usb/drivers_autoprobe
echo 0 > /sys/subsystem/pcmcia/drivers_autoprobe
...
and initiate the probing with udev rules like:
ACTION=="add", SUBSYSTEM=="usb", ATTR{subsystem/drivers_probe}="$kernel"
ACTION=="add", SUBSYSTEM=="pcmcia", ATTR{subsystem/drivers_probe}="$kernel"
...
Custom driver binding can happen in earlier rules by something like:
ACTION=="add", SUBSYSTEM=="usb", \
ATTRS{idVendor}=="1234", ATTRS{idProduct}=="5678" \
ATTR{subsystem/drivers/<custom-driver>/bind}="$kernel"
This is intended to solve the modprobe.conf mess with "install-rules", custom
bind/unbind-scripts and all the weird things people invented over the years.
It should also provide the functionality "libusual" was supposed to do.
With udev, one can just write a udev rule to drive all USB-disks at the
third port of USB-hub by the "ub" driver, and everything else by
usb-storage. One can also instruct udev to bind different wireless
drivers to identical cards - just selected by the pcmcia slot-number, and
whatever ...
To use the mentioned rules, it needs udev version 106, to be able to
write ATTR{}="$kernel" to sysfs files.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
- uses a kset in "struct class" to keep track of all directories
belonging to this class
- merges with the /sys/devices/virtual logic.
- removes the namespace-dir if the last member of that class
leaves the directory.
There may be locking or refcounting fixes left, I stopped when it seemed
to work with network and sound modules. :)
From: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as868) adds a helper routine for device drivers that need
to set up a callback to perform some action in a different process's
context. This is intended for use by attribute methods that want to
unregister themselves or their parent device. Attribute method calls
are mutually exclusive with unregistration, so such actions cannot be
taken directly.
Two attribute methods are converted to use the new helper routine: one
for SCSI device deletion and one for System/390 ccwgroup devices.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
No one uses it, and it wasn't exported to modules, so remove it. The
only other user of it was the network code, which is now converted to
use struct device instead.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial: (25 commits)
Documentation/kernel-docs.txt update.
arch/cris: typo in KERN_INFO
Storage class should be before const qualifier
kernel/printk.c: comment fix
update I/O sched Kconfig help texts - CFQ is now default, not AS.
Remove duplicate listing of Cris arch from README
kbuild: more doc. cleanups
doc: make doc. for maxcpus= more visible
drivers/net/eexpress.c: remove duplicate comment
add a help text for BLK_DEV_GENERIC
correct a dead URL in the IP_MULTICAST help text
fix the BAYCOM_SER_HDX help text
fix SCSI_SCAN_ASYNC help text
trivial documentation patch for platform.txt
Fix typos concerning hierarchy
Fix comment typo "spin_lock_irqrestore".
Fix misspellings of "agressive".
drivers/scsi/a100u2w.c: trivial typo patch
Correct trivial typo in log2.h.
Remove useless FIND_FIRST_BIT() macro from cardbus.c.
...
Implement device resource management, in short, devres. A device
driver can allocate arbirary size of devres data which is associated
with a release function. On driver detach, release function is
invoked on the devres data, then, devres data is freed.
devreses are typed by associated release functions. Some devreses are
better represented by single instance of the type while others need
multiple instances sharing the same release function. Both usages are
supported.
devreses can be grouped using devres group such that a device driver
can easily release acquired resources halfway through initialization
or selectively release resources (e.g. resources for port 1 out of 4
ports).
This patch adds devres core including documentation and the following
managed interfaces.
* alloc/free : devm_kzalloc(), devm_kzfree()
* IO region : devm_request_region(), devm_release_region()
* IRQ : devm_request_irq(), devm_free_irq()
* DMA : dmam_alloc_coherent(), dmam_free_coherent(),
dmam_declare_coherent_memory(), dmam_pool_create(),
dmam_pool_destroy()
* PCI : pcim_enable_device(), pcim_pin_device(), pci_is_managed()
* iomap : devm_ioport_map(), devm_ioport_unmap(), devm_ioremap(),
devm_ioremap_nocache(), devm_iounmap(), pcim_iomap_table(),
pcim_iomap(), pcim_iounmap()
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
For the block subsystem, we want to delay all uevents until the
disk has been scanned and allpartitons are already created before
the first event is sent out.
Signed-off-by: Kay Sievers <kay.sievers@novell.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This allows us to add type specific attributes, uevent vars and
release funtions.
A subsystem can carry different types of devices like the "block"
subsys has disks and partitions. Both types create a different set
of attributes, but belong to the same subsystem.
This corresponds to the low level objects:
kobject -> device (object/device data)
kobj_type -> device_type (type of object/device we are embedded in)
kset -> class/bus (list of objects/devices of a subsystem)
Signed-off-by: Kay Sievers <kay.sievers@novell.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add a prototype for driver_init() in include/linux/device.h.
Also remove a static function of the same name in drivers/acpi/ibm_acpi.c to
ibm_acpi_driver_init() to fix the namespace collision.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
For node-aware skb allocations we need information about the node in struct
net_device or struct device. Davem suggested to put it into struct device
which this patch does.
In particular:
- struct device gets a new int numa_node member if CONFIG_NUMA is set
- there are two new helpers, dev_to_node and set_dev_node to
transparently deal with the non-numa case
- for pci devices the node-info is set to the value we get from
pcibus_to_node.
Note that for some architectures pcibus_to_node doesn't work yet at the time
we call it currently. This is harmless and will just mean skb allocations
aren't node-local on this architectures until the implementation of
pcibus_to_node on these architectures have been updated (There are patches for
x86 and x86_64 floating around)
[akpm@osdl.org: cleanup]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide a function device_move() to move a device to a new parent device. Add
auxilliary functions kobject_move() and sysfs_move_dir().
kobject_move() generates a new uevent of type KOBJ_MOVE, containing the
previous path (DEVPATH_OLD) in addition to the usual values. For this, a new
interface kobject_uevent_env() is created that allows to add further
environmental data to the uevent at the kobject layer.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Change ACPI to use dev_archdata instead of firmware_data
This patch changes ACPI to use the new dev_archdata on i386, x86_64
and ia64 (is there any other arch using ACPI ?) to store it's
acpi_handle.
It also removes the firmware_data field from struct device as this
was the only user.
Only build-tested on x86
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add arch specific dev_archdata to struct device
Adds an arch specific struct dev_arch to struct device. This enables
architecture to add specific fields to every device in the system, like
DMA operation pointers, NUMA node ID, firmware specific data, etc...
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Andi Kleen <ak@suse.de>
Acked-By: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg 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: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Greg 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: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg 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: Greg 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: Greg 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: Greg 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: Greg 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: Greg 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: David Brownell <dbrownell@users.sourceforge.net>
Cc: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Greg 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: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Greg Kroah-Hartman <gregkh@suse.de>
David Brownell
Linus Torvalds
Adrian Bunk
Greg Kroah-Hartman
Dan Williams
Alan Stern
Dmitry Torokhov
Cornelia Huck
Kay Sievers
Robert P. J. Day
Tejun Heo
Kay Sievers
Christoph Hellwig
Benjamin Herrenschmidt
Russell King
Andrew Morton
Linus Torvalds
Miguel Ojeda Sandonis