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path: root/drivers/base/bus.c
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2008-01-24Kobject: change drivers/base/bus to use kobject_init_and_addGreg Kroah-Hartman
Stop using kobject_register, as this way we can control the sending of the uevent properly, after everything is properly initialized. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24Driver core: clean up debugging messagesGreg Kroah-Hartman
The driver core debugging messages are a mess. This provides a unified message that makes them actually useful. The format for new kobject debug messages should be: driver/bus/class: 'OBJECT_NAME': FUNCTION_NAME: message.\n Note, the class code is not changed in this patch due to pending patches in my queue that this would conflict with. A later patch will clean them up. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24Driver core: move the static kobject out of struct driverGreg Kroah-Hartman
This patch removes the kobject, and a few other driver-core-only fields out of struct driver and into the driver core only. Now drivers can be safely create on the stack or statically (like they currently are.) Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24driver core: remove fields from struct bus_typeGreg Kroah-Hartman
struct bus_type is static everywhere in the kernel. This moves the kobject in the structure out of it, and a bunch of other private only to the driver core fields are now moved to a private structure. This lets us dynamically create the backing kobject properly and gives us the chance to be able to document to users exactly how to use the struct bus_type as there are no fields they can improperly access. Thanks to Kay for the build fixes on this patch. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24driver core: add way to get to bus device klistGreg Kroah-Hartman
This allows an easier way to get to the device klist associated with a struct bus_type (you have three to choose from...) This will make it easier to move these fields to be dynamic in a future patch. The only user of this is the PCI core which horribly abuses this interface to rearrange the order of the pci devices. This should be done using the existing bus device walking functions, but that's left for future patches. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24driver core: add way to get to bus ksetGreg Kroah-Hartman
This allows an easier way to get to the kset associated with a struct bus_type (you have three to choose from...) This will make it easier to move these fields to be dynamic in a future patch. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24kobject: remove subsystem_(un)register functionsGreg Kroah-Hartman
These functions are no longer used and are the last remants of the old subsystem crap. So delete them for good. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24kset: convert struct bus_device->drivers to use kset_createGreg Kroah-Hartman
Dynamically create the kset instead of declaring it statically. Having 3 static kobjects in one structure is not only foolish, but ripe for nasty race conditions if handled improperly. We also rename the field to catch any potential users of it (not that there should be outside of the driver core...) Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24kset: convert struct bus_device->devices to use kset_createGreg Kroah-Hartman
Dynamically create the kset instead of declaring it statically. Having 3 static kobjects in one structure is not only foolish, but ripe for nasty race conditions if handled improperly. We also rename the field to catch any potential users of it (not that there should be outside of the driver core...) Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24kset: convert drivers/base/bus.c to use kset_createGreg Kroah-Hartman
Dynamically create the kset instead of declaring it statically. Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24kobject: remove struct kobj_type from struct ksetGreg Kroah-Hartman
We don't need a "default" ktype for a kset. We should set this explicitly every time for each kset. This change is needed so that we can make ksets dynamic, and cleans up one of the odd, undocumented assumption that the kset/kobject/ktype model has. This patch is based on a lot of help from Kay Sievers. Nasty bug in the block code was found by Dave Young <hidave.darkstar@gmail.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12Driver core: rename ktype_driverGreg Kroah-Hartman
This makes it a bit more sane when trying to figure out how to clean up the ktype mess. Based on a larger patch from Kay Sievers Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12Driver core: add uevent file for bus and driverKay Sievers
This has been in the SuSE kernels for some time now. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12Driver core: remove get_bus()Greg Kroah-Hartman
get_bus() should not be globally visable as it is not used by anything other than drivers/base/bus.c. This patch removes the visability of it, and renames it to match all of the other *_get() functions in the kernel. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12Driver core: remove put_bus()Greg Kroah-Hartman
put_bus() should not be globally visable as it is not used by anything other than drivers/base/bus.c. This patch removes the visability of it, and renames it to match all of the other *_put() functions in the kernel. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12Driver core: remove subsys_get()Greg Kroah-Hartman
There are no more subsystems, it's a kset now so remove the function and the only two users, which are in the driver core. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12Driver core: remove subsys_put()Greg Kroah-Hartman
There are no more subsystems, it's a kset now so remove the function and the only two users, which are in the driver core. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12Driver core: remove subsys_set_ksetGreg Kroah-Hartman
This macro is only used by the driver core and is held over from when we had subsystems. It is not needed anymore. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-10-12Driver core: make sysfs uevent-attributes staticKay Sievers
Attributes do not have an owner(module) anymore, so there is no need to carry the attributes in every single bus instance. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Acked-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-07-11sysfs: kill unnecessary attribute->ownerTejun Heo
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>
2007-07-11Driver core: coding style cleanupCornelia Huck
This converts code of the form if ((error = some_func())) goto fixup; to error = some_func(); if (error) goto fixup; Signed-off-by: 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>
2007-07-11Driver core: add missing kset ueventKay Sievers
We get uevents for a bus/class going away, but not one registering. Add the missing uevent in kset_register(), which will send an event for a new bus/class. Suppress all unwanted uevents for bus subdirectories like /bus/*/devices/, /bus/*/drivers/. Now we get for module usbcore: add /module/usbcore (module) add /bus/usb (bus) add /class/usb_host (class) add /bus/usb/drivers/hub (drivers) add /bus/usb/drivers/usb (drivers) remove /bus/usb/drivers/usb (drivers) remove /bus/usb/drivers/hub (drivers) remove /class/usb_host (class) remove /bus/usb (bus) remove /module/usbcore (module) instead of: add /module/usbcore (module) add /bus/usb/drivers/hub (drivers) add /bus/usb/drivers/usb (drivers) remove /bus/usb/drivers/usb (drivers) remove /bus/usb/drivers/hub (drivers) remove /class/usb_host (class) remove /bus/usb/drivers (bus) remove /bus/usb/devices (bus) remove /bus/usb (bus) remove /module/usbcore (module) Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-05-02remove "struct subsystem" as it is no longer neededGreg Kroah-Hartman
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>
2007-04-27driver core: bus_add_driver should return an error if no busGreg Kroah-Hartman
As pointed out by Dave Jones. Cc: Dave Jones <davej@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-04-27Driver core: remove unneeded completion from driver release pathGreg Kroah-Hartman
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>
2007-04-27driver core: don't fail attaching the device if it cannot be boundCornelia Huck
Don't fail bus_attach_device() if the device cannot be bound. If dev->driver has been specified, reset it to NULL if device_bind_driver() failed and add the device as an unbound device. As a result, bus_attach_device() now cannot fail, and we can remove some checking from device_add(). Also remove an unneeded check in bus_rescan_devices_helper(). Signed-off-by: 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>
2007-04-27Driver core: udev triggered device-<>driver bindingKay Sievers
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>
2007-02-16Driver core: device_add_attrs() cleanupAndrew Morton
Clean up the coding in device_add_attrs() a bit. Cc: Jean Delvare <khali@linux-fr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-12-01CONFIG_SYSFS_DEPRECATED - bus symlinksKay Sievers
Turn off the bus symlinks if CONFIG_SYSFS_DEPRECATED is enabled Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-12-01Driver core: add notification of bus eventsBenjamin Herrenschmidt
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>
2006-10-18Driver core: bus: remove indentation levelJeff Garzik
Before potentially fixing up these functions, this cosmetic change reduces the indentation level to make the code easier to read and maintain. No functional changes at all. Signed-off-by: Jeff Garzik <jeff@garzik.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-10-18Driver core: Don't ignore error returns from probingAlan Stern
This patch (as797) fixes device_add() in the driver core. It needs to pay attention when the driver for a new device reports an error. At the same time, since bus_remove_device() undoes the effects of both bus_add_device() and bus_attach_device(), it needs to check whether the bus_attach_device step failed. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-10-18driver core fixes: bus_add_device() cleanup on errorCornelia Huck
Correct cleanup in the error path of bus_add_device(). Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-10-18driver core fixes: bus_add_attrs() retval checkCornelia Huck
Check return value of bus_add_attrs() in bus_register(). Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-25Driver core: Remove unneeded routines from driver coreAlan Stern
This patch (as783) simplifies the driver core slightly by removing four unnecessary _get and _put methods. It is vital that when a driver is removed from its bus's klist of registered drivers, or when a device is removed from a driver's klist of bound devices, that the klist updates complete synchronously. Otherwise the kernel might try binding an unregistered driver to a newly-registered device, or adding a device to the klist for a new driver before it has been removed from the old driver's klist. Since the removals must be synchronous, they don't need to update any reference counts. Hence the _get and _put methods can be dispensed with. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-25Driver core: Fix potential deadlock in driver coreAlan Stern
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>
2006-09-25drivers/base: check errorsAndrew Morton
Add lots of return-value checking. <pcornelia.huck@de.ibm.com>: fix bus_rescan_devices()] Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-25Driver core: fixed add_bind_files() definitionYoichi Yuasa
When CONFIG_HOTPLUG is n, add_bind_files() definition is wrong. This patch has fixed it. Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-07-12[PATCH] Driver core: bus.c cleanupsAdrian Bunk
This patch contains the following cleanups: - make the needlessly global bus_subsys static - #if 0 the unused find_bus() Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-06-30Remove obsolete #include <linux/config.h>Jörn Engel
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-06-21[PATCH] Driver core: add generic "subsystem" link to all devicesKay Sievers
Like the SUBSYTEM= key we find in the environment of the uevent, this creates a generic "subsystem" link in sysfs for every device. Userspace usually doesn't care at all if its a "class" or a "bus" device. This provides an unified way to determine the subsytem of a device, regardless of the way the driver core has created it. Signed-off-by: Kay Sievers <kay.sievers@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-06-21[PATCH] Driver Core: remove unused exportsGreg Kroah-Hartman
Cc: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-06-21[PATCH] Driver core: bus device event delayKay Sievers
split bus_add_device() and send device uevents after sysfs population Signed-off-by: Kay Sievers <kay.sievers@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-04-14[PATCH] driver core: driver_bind attribute returns incorrect valueRyan Wilson
The manual driver <-> device binding attribute in sysfs doesn't return the correct value on failure or success of driver_probe_device. driver_probe_device returns 1 on success (the driver accepted the device) or 0 on probe failure (when the driver didn't accept the device but no real error occured). However, the attribute can't just return 0 or 1, it must return the number of bytes consumed from buf or an error value. Returning 0 indicates to userspace that nothing was written (even though the kernel has tried to do the bind/probe and failed). Returning 1 indicates that only one character was accepted in which case userspace will re-try the write with a partial string. A more correct version of driver_bind would return count (to indicate the entire string was consumed) when driver_probe_device returns 1 and -ENODEV when driver_probe_device returns 0. This patch makes that change. Signed-off-by: Ryan Wilson <hap9@epoch.ncsc.mil> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-03-14[SCSI] drivers/base/bus.c - export reprobeMoore, Eric
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: Eric Moore <Eric.Moore@lsil.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
2006-02-07[PATCH] drivers/base/bus.c warning fixesRussell King
drivers/base/bus.c:166: warning: `driver_attr_unbind' defined but not used drivers/base/bus.c:194: warning: `driver_attr_bind' defined but not used Looks like these two attributes and supporting functions want to be #ifdef HOTPLUG'd Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-04[PATCH] Driver core: only all userspace bind/unbind if CONFIG_HOTPLUG is enabledGreg Kroah-Hartman
Thanks to drivers making their id tables __devinit, we can't allow userspace to bind or unbind drivers from devices manually through sysfs. So we only allow this if CONFIG_HOTPLUG is enabled. Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-01-04[PATCH] Hold the device's parent's lock during probe and removeAlan Stern
This patch (as604) makes the driver core hold a device's parent's lock as well as the device's lock during calls to the probe and remove methods in a driver. This facility is needed by USB device drivers, owing to the peculiar way USB devices work: A device provides multiple interfaces, and drivers are bound to interfaces rather than to devices; Nevertheless a reset, reset-configuration, suspend, or resume affects the entire device and requires the caller to hold the lock for the device, not just a lock for one of the interfaces. Since a USB driver's probe method is always called with the interface lock held, the locking order rules (always lock parent before child) prevent these methods from acquiring the device lock. The solution provided here is to call all probe and remove methods, for all devices (not just USB), with the parent lock already acquired. Although currently only the USB subsystem requires these changes, people have mentioned in prior discussion that the overhead of acquiring an extra semaphore in all the prove/remove sequences is not overly large. Up to now, the USB core has been using its own set of private semaphores. A followup patch will remove them, relying entirely on the device semaphores provided by the driver core. The code paths affected by this patch are: device_add and device_del: The USB core already holds the parent lock, so no actual change is needed. driver_register and driver_unregister: The driver core will now lock both the parent and the device before probing or removing. driver_bind and driver_unbind (in sysfs): These routines will now lock both the parent and the device before binding or unbinding. bus_rescan_devices: The helper routine will lock the parent before probing a device. I have not tested this patch for conflicts with other subsystems. As far as I can see, the only possibility of conflict would lie in the bus_rescan_devices pathway, and it seems pretty remote. Nevertheless, it would be good for this to get a lot of testing in -mm. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-11-23[PATCH] Small fixes to driver coreAlan Stern
This patch (as603) makes a few small fixes to the driver core: Change spin_lock_irq for a klist lock to spin_lock; Fix reference count leaks; Minor spelling and formatting changes. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by Patrick Mochel <mochel@digitalimplant.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-07[PATCH] fix klist semantics for lists which have elements removed on traversalJames Bottomley
The problem is that klists claim to provide semantics for safe traversal of lists which are being modified. The failure case is when traversal of a list causes element removal (a fairly common case). The issue is that although the list node is refcounted, if it is embedded in an object (which is universally the case), then the object will be freed regardless of the klist refcount leading to slab corruption because the klist iterator refers to the prior element to get the next. The solution is to make the klist take and release references to the embedding object meaning that the embedding object won't be released until the list relinquishes the reference to it. (akpm: fast-track this because it's needed for the 2.6.13 scsi merge) Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>