linux/drivers/char/misc.c, branch v6.17

char: misc: Rename a local variable in misc_init()

2025-07-01T10:29:52Z

Local variable @ret is not used for return value in misc_init(). Give it a different name @misc_proc_file. Signed-off-by: Zijun Hu Link: https://lore.kernel.org/r/20250625-fix_mischar-v2-1-25a80f41b090@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman

char: misc: Fix improper and inaccurate error code returned by misc_init()

2025-06-24T15:48:34Z

misc_init() returns -EIO for __register_chrdev() invocation failure, but: - -EIO is for I/O error normally, but __register_chrdev() does not do I/O. - -EIO can not cover various error codes returned by __register_chrdev(). Fix by returning error code of __register_chrdev(). Signed-off-by: Zijun Hu Link: https://lore.kernel.org/r/20250620-fix_mischar-v1-3-6c2716bbf1fa@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman

Merge 6.15-rc4 into char-misc-next

2025-04-28T07:45:00Z

We need the char-misc fixes in here as well. Signed-off-by: Greg Kroah-Hartman

char: misc: restrict the dynamic range to exclude reserved minors

2025-04-25T13:56:42Z

When this was first reported [1], the possibility of having sufficient number of dynamic misc devices was theoretical, in the case of dlm driver. In practice, its userspace never created more than one device. What we know from commit ab760791c0cf ("char: misc: Increase the maximum number of dynamic misc devices to 1048448"), is that the miscdevice interface has been used for allocating more than the single-shot devices it was designed for. And it is not only coresight_tmc, but many other drivers are able to create multiple devices. On systems like the ones described in the above commit, it is certain that the dynamic allocation will allocate certain reserved minor numbers, leading to failures when a later driver tries to claim its reserved number. Instead of excluding the historically statically allocated range from dynamic allocation, restrict the latter to minors above 255. That also removes the need for DYNAMIC_MINORS and the convolution in allocating minor numbers, simplifying the code. Since commit ab760791c0cf ("char: misc: Increase the maximum number of dynamic misc devices to 1048448") has been applied, such range is already possible. And given such devices already need to be dynamically created, there should be no systems where this might become a problem. [1] https://lore.kernel.org/all/1257813017-28598-3-git-send-email-cascardo@holoscopio.com/ Signed-off-by: Thadeu Lima de Souza Cascardo Link: https://lore.kernel.org/r/20250423-misc-dynrange-v4-1-133b5ae4ca18@igalia.com Signed-off-by: Greg Kroah-Hartman

char: misc: register chrdev region with all possible minors

2025-04-15T14:22:15Z

register_chrdev will only register the first 256 minors of a major chrdev. That means that dynamically allocated misc devices with minor above 255 will fail to open with -ENXIO. This was found by kernel test robot when testing a different change that makes all dynamically allocated minors be above 255. This has, however, been separately tested by creating 256 serio_raw devices with the help of userio driver. Ever since allowing misc devices with minors above 128, this has been possible. Fix it by registering all minor numbers from 0 to MINORMASK + 1 for MISC_MAJOR. Reported-by: kernel test robot Cc: stable Closes: https://lore.kernel.org/oe-lkp/202503171507.6c8093d0-lkp@intel.com Fixes: ab760791c0cf ("char: misc: Increase the maximum number of dynamic misc devices to 1048448") Signed-off-by: Thadeu Lima de Souza Cascardo Tested-by: Hou Wenlong Link: https://lore.kernel.org/r/20250317-misc-chrdev-v1-1-6cd05da11aef@igalia.com Signed-off-by: Greg Kroah-Hartman

char: misc: deallocate static minor in error path

2025-02-20T14:21:34Z

When creating sysfs files fail, the allocated minor must be freed such that it can be later reused. That is specially harmful for static minor numbers, since those would always fail to register later on. Fixes: 6d04d2b554b1 ("misc: misc_minor_alloc to use ida for all dynamic/misc dynamic minors") Cc: stable Signed-off-by: Thadeu Lima de Souza Cascardo Link: https://lore.kernel.org/r/20250123123249.4081674-5-cascardo@igalia.com Signed-off-by: Greg Kroah-Hartman

misc: misc_minor_alloc to use ida for all dynamic/misc dynamic minors

2025-01-08T12:18:10Z

misc_minor_alloc was allocating id using ida for minor only in case of MISC_DYNAMIC_MINOR but misc_minor_free was always freeing ids using ida_free causing a mismatch and following warn: > > WARNING: CPU: 0 PID: 159 at lib/idr.c:525 ida_free+0x3e0/0x41f > > ida_free called for id=127 which is not allocated. > > <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< ... > > [<60941eb4>] ida_free+0x3e0/0x41f > > [<605ac993>] misc_minor_free+0x3e/0xbc > > [<605acb82>] misc_deregister+0x171/0x1b3 misc_minor_alloc is changed to allocate id from ida for all minors falling in the range of dynamic/ misc dynamic minors Fixes: ab760791c0cf ("char: misc: Increase the maximum number of dynamic misc devices to 1048448") Signed-off-by: Vimal Agrawal Reviewed-by: Dirk VanDerMerwe Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20241021133812.23703-1-vimal.agrawal@sophos.com Signed-off-by: Greg Kroah-Hartman

char: misc: make misc_class a static const structure

2023-06-23T08:27:15Z

Now that the driver core allows for struct class to be in read-only memory, move the misc_class structure to be declared at build time placing it into read-only memory, instead of having to be dynamically allocated at load time. Cc: Arnd Bergmann Suggested-by: Greg Kroah-Hartman Signed-off-by: Ivan Orlov Link: https://lore.kernel.org/r/20230620143751.578239-14-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

driver core: class: remove module * from class_create()

2023-03-17T14:16:33Z

The module pointer in class_create() never actually did anything, and it shouldn't have been requred to be set as a parameter even if it did something. So just remove it and fix up all callers of the function in the kernel tree at the same time. Cc: "Rafael J. Wysocki" Acked-by: Benjamin Tissoires Link: https://lore.kernel.org/r/20230313181843.1207845-4-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

Merge tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2022-12-16T11:54:54Z

Pull driver core updates from Greg KH: "Here is the set of driver core and kernfs changes for 6.2-rc1. The "big" change in here is the addition of a new macro, container_of_const() that will preserve the "const-ness" of a pointer passed into it. The "problem" of the current container_of() macro is that if you pass in a "const *", out of it can comes a non-const pointer unless you specifically ask for it. For many usages, we want to preserve the "const" attribute by using the same call. For a specific example, this series changes the kobj_to_dev() macro to use it, allowing it to be used no matter what the const value is. This prevents every subsystem from having to declare 2 different individual macros (i.e. kobj_const_to_dev() and kobj_to_dev()) and having the compiler enforce the const value at build time, which having 2 macros would not do either. The driver for all of this have been discussions with the Rust kernel developers as to how to properly mark driver core, and kobject, objects as being "non-mutable". The changes to the kobject and driver core in this pull request are the result of that, as there are lots of paths where kobjects and device pointers are not modified at all, so marking them as "const" allows the compiler to enforce this. So, a nice side affect of the Rust development effort has been already to clean up the driver core code to be more obvious about object rules. All of this has been bike-shedded in quite a lot of detail on lkml with different names and implementations resulting in the tiny version we have in here, much better than my original proposal. Lots of subsystem maintainers have acked the changes as well. Other than this change, included in here are smaller stuff like: - kernfs fixes and updates to handle lock contention better - vmlinux.lds.h fixes and updates - sysfs and debugfs documentation updates - device property updates All of these have been in the linux-next tree for quite a while with no problems" * tag 'driver-core-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (58 commits) device property: Fix documentation for fwnode_get_next_parent() firmware_loader: fix up to_fw_sysfs() to preserve const usb.h: take advantage of container_of_const() device.h: move kobj_to_dev() to use container_of_const() container_of: add container_of_const() that preserves const-ness of the pointer driver core: fix up missed drivers/s390/char/hmcdrv_dev.c class.devnode() conversion. driver core: fix up missed scsi/cxlflash class.devnode() conversion. driver core: fix up some missing class.devnode() conversions. driver core: make struct class.devnode() take a const * driver core: make struct class.dev_uevent() take a const * cacheinfo: Remove of_node_put() for fw_token device property: Add a blank line in Kconfig of tests device property: Rename goto label to be more precise device property: Move PROPERTY_ENTRY_BOOL() a bit down device property: Get rid of __PROPERTY_ENTRY_ARRAY_EL*SIZE*() kernfs: fix all kernel-doc warnings and multiple typos driver core: pass a const * into of_device_uevent() kobject: kset_uevent_ops: make name() callback take a const * kobject: kset_uevent_ops: make filter() callback take a const * kobject: make kobject_namespace take a const * ...