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* sysfs: constify sysfs create/remove files harderJani Nikula2018-12-031-4/+4
| | | | | | | | | | | | Let the passed in array be const (and thus placed in rodata) instead of a mutable array of const pointers. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181004143750.30880-1-jani.nikula@intel.com
* Merge tag 'driver-core-4.19-rc1' of ↵Linus Torvalds2018-08-181-3/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here are all of the driver core and related patches for 4.19-rc1. Nothing huge here, just a number of small cleanups and the ability to now stop the deferred probing after init happens. All of these have been in linux-next for a while with only a merge issue reported" * tag 'driver-core-4.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (21 commits) base: core: Remove WARN_ON from link dependencies check drivers/base: stop new probing during shutdown drivers: core: Remove glue dirs from sysfs earlier driver core: remove unnecessary function extern declare sysfs.h: fix non-kernel-doc comment PM / Domains: Stop deferring probe at the end of initcall iommu: Remove IOMMU_OF_DECLARE iommu: Stop deferring probe at end of initcalls pinctrl: Support stopping deferred probe after initcalls dt-bindings: pinctrl: add a 'pinctrl-use-default' property driver core: allow stopping deferred probe after init driver core: add a debugfs entry to show deferred devices sysfs: Fix internal_create_group() for named group updates base: fix order of OF initialization linux/device.h: fix kernel-doc notation warning Documentation: update firmware loader fallback reference kobject: Replace strncpy with memcpy drivers: base: cacheinfo: use OF property_read_u32 instead of get_property,read_number kernfs: Replace strncpy with memcpy device: Add #define dev_fmt similar to #define pr_fmt ...
| * sysfs.h: fix non-kernel-doc commentRandy Dunlap2018-07-161-3/+3
| | | | | | | | | | | | | | | | | | | | Don't use "/**" to begin this comment block since it is not a kernel-doc comment block. Also adjust comment line to fit in 80 characters. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | scsi: sysfs: Introduce sysfs_{un,}break_active_protection()Bart Van Assche2018-08-021-0/+14
|/ | | | | | | | | | | Introduce these two functions and export them such that the next patch can add calls to these functions from the SCSI core. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: <stable@vger.kernel.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
* sysfs.h: Use octal permissionsJoe Perches2018-01-091-8/+6
| | | | | | | Use the more common and preferred octal directly. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* efi: Move some sysfs files to be read-only by rootGreg Kroah-Hartman2017-12-061-0/+6
| | | | | | | | | | | | | | | | | | | | | Thanks to the scripts/leaking_addresses.pl script, it was found that some EFI values should not be readable by non-root users. So make them root-only, and to do that, add a __ATTR_RO_MODE() macro to make this easier, and use it in other places at the same time. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Tested-by: Dave Young <dyoung@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Cc: stable <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20171206095010.24170-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: remove signedness from sysfs_get_direntNick Desaulniers2017-05-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | sysfs_get_dirent is usually invoked with a string literal, which have the type char[]. While the toplevel Makefile disables -Wpointer-sign, other Makefiles like arch/x86/boot/compressed/Makefile redefine KBUILD_CFLAGS. Fixes the warning: In file included from arch/x86/boot/compressed/kaslr.c:17: In file included from ./include/linux/module.h:17: In file included from ./include/linux/kobject.h:21: ./include/linux/sysfs.h:517:37: warning: passing 'const unsigned char *' to parameter of type 'const char *' converts between pointers to integer types with different sign [-Wpointer-sign] return kernfs_find_and_get(parent, name); ^~~~ ./include/linux/kernfs.h:462:57: note: passing argument to parameter 'name' here kernfs_find_and_get(struct kernfs_node *kn, const char *name) ^ Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'chrome-platform-4.4' of ↵Linus Torvalds2015-11-131-4/+14
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/olof/chrome-platform Pull chrome platform updates from Olof Johansson: "Here's the branch of chrome platform changes for v4.4. Some have been queued up for the full 4.3 release cycle since I forgot to send them in for that round (rebased early on to deal with fixes conflicts). Most of these enable EC communication stuff -- Pixel 2015 support, enabling building for ARM64 platforms, and a few fixes for memory leaks. There's also a patch in here to allow reading/writing the verified boot context, which depends on a sysfs patch acked by Greg" * tag 'chrome-platform-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/olof/chrome-platform: platform/chrome: Fix i2c-designware adapter name platform/chrome: Support reading/writing the vboot context sysfs: Support is_visible() on binary attributes platform/chrome: cros_ec: Fix possible leak in led_rgb_store() platform/chrome: cros_ec: Fix leak in sequence_store() platform/chrome: Enable Chrome platforms on 64-bit ARM platform/chrome: cros_ec_dev - Add a platform device ID table platform/chrome: cros_ec_lpc - Add support for Google Pixel 2 platform/chrome: cros_ec_lpc - Use existing function to check EC result platform/chrome: Make depends on MFD_CROS_EC instead CROS_EC_PROTO Revert "platform/chrome: Don't make CHROME_PLATFORMS depends on X86 || ARM"
| * sysfs: Support is_visible() on binary attributesEmilio López2015-10-071-4/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | According to the sysfs header file: "The returned value will replace static permissions defined in struct attribute or struct bin_attribute." but this isn't the case, as is_visible is only called on struct attribute only. This patch introduces a new is_bin_visible() function to implement the same functionality for binary attributes, and updates documentation accordingly. Note that to keep functionality and code similar to that of normal attributes, the mode is now checked as well to ensure it contains only read/write permissions or SYSFS_PREALLOC. Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Emilio López <emilio.lopez@collabora.co.uk> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Olof Johansson <olof@lixom.net>
* | sysfs: added __compat_only_sysfs_link_entry_to_kobj()Jarkko Sakkinen2015-10-191-0/+11
|/ | | | | | | | | | Added a new function __compat_only_sysfs_link_group_to_kobj() that adds a symlink from attribute or group to a kobject. This needed for maintaining backwards compatibility with PPI attributes in the TPM driver. Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
* sysfs: Add support for permanently empty directories to serve as mount points.Eric W. Biederman2015-07-011-0/+15
| | | | | | | | | | | | Add two functions sysfs_create_mount_point and sysfs_remove_mount_point that hang a permanently empty directory off of a kobject or remove a permanently emptpy directory hanging from a kobject. Export these new functions so modular filesystems can use them. Cc: stable@vger.kernel.org Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* sysfs: Document struct attribute_groupGuenter Roeck2015-03-251-0/+15
| | | | | | | | | Document variables defined in struct attribute_group to ensure correct usage. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs/kernfs: allow attributes to request write buffer be pre-allocated.NeilBrown2014-11-071-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | md/raid allows metadata management to be performed in user-space. A various times, particularly on device failure, the metadata needs to be updated before further writes can be permitted. This means that the user-space program which updates metadata much not block on writeout, and so must not allocate memory. mlockall(MCL_CURRENT|MCL_FUTURE) and pre-allocation can avoid all memory allocation issues for user-memory, but that does not help kernel memory. Several kernel objects can be pre-allocated. e.g. files opened before any writes to the array are permitted. However some kernel allocation happens in places that cannot be pre-allocated. In particular, writes to sysfs files (to tell md that it can now allow writes to the array) allocate a buffer using GFP_KERNEL. This patch allows attributes to be marked as "PREALLOC". In that case the maximal buffer is allocated when the file is opened, and then used on each write instead of allocating a new buffer. As the same buffer is now shared for all writes on the same file description, the mutex is extended to cover full use of the buffer including the copy_from_user(). The new __ATTR_PREALLOC() 'or's a new flag in to the 'mode', which is inspected by sysfs_add_file_mode_ns() to determine if the file should be marked as requiring prealloc. Despite the comment, we *do* use ->seq_show together with ->prealloc in this patch. The next patch fixes that. Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs.h: don't return a void-valued expression in sysfs_remove_fileSimon Wunderlich2014-05-271-1/+1
| | | | | | | | Sparse was complaining about that: include/linux/sysfs.h:432:9: warning: returning void-valued expression Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()Tejun Heo2014-04-161-9/+0
| | | | | | | | | All device_schedule_callback_owner() users are converted to use device_remove_file_self(). Remove now unused {sysfs|device}_schedule_callback_owner(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'modules-next-for-linus' of ↵Linus Torvalds2014-04-061-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull module updates from Rusty Russell: "Nothing major: the stricter permissions checking for sysfs broke a staging driver; fix included. Greg KH said he'd take the patch but hadn't as the merge window opened, so it's included here to avoid breaking build" * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: staging: fix up speakup kobject mode Use 'E' instead of 'X' for unsigned module taint flag. VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms. kallsyms: fix percpu vars on x86-64 with relocation. kallsyms: generalize address range checking module: LLVMLinux: Remove unused function warning from __param_check macro Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE module: remove MODULE_GENERIC_TABLE module: allow multiple calls to MODULE_DEVICE_TABLE() per module module: use pr_cont
| * VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms.Rusty Russell2014-03-241-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary of http://lkml.org/lkml/2014/3/14/363 : Ted: module_param(queue_depth, int, 444) Joe: 0444! Rusty: User perms >= group perms >= other perms? Joe: CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2? Side effect of stricter permissions means removing the unnecessary S_IFREG from several callers. Note that the BUILD_BUG_ON_ZERO((perm) & 2) test was removed: a fair number of drivers fail this test, so that will be the debate for a future patch. Suggested-by: Joe Perches <joe@perches.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> for drivers/pci/slot.c Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | Revert "sysfs, driver-core: remove unused ↵Greg Kroah-Hartman2014-03-251-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | {sysfs|device}_schedule_callback_owner()" This reverts commit d1ba277e79889085a2faec3b68b91ce89c63f888. As reported by Stephen, this patch breaks linux-next as a ppc patch suddenly (after 2 years) started using this old api call. So revert it for now, it will go away in 3.15-rc2 when we can change the PPC call to the new api. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tejun Heo <tj@kernel.org> Cc: Stewart Smith <stewart@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | sysfs, kobject: add sysfs wrapper for kernfs_enable_ns()Tejun Heo2014-02-071-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, kobject is invoking kernfs_enable_ns() directly. This is fine now as sysfs and kernfs are enabled and disabled together. If sysfs is disabled, kernfs_enable_ns() is switched to dummy implementation too and everything is fine; however, kernfs will soon have its own config option CONFIG_KERNFS and !SYSFS && KERNFS will be possible, which can make kobject call into non-dummy kernfs_enable_ns() with NULL kernfs_node pointers leading to an oops. Introduce sysfs_enable_ns() which is a wrapper around kernfs_enable_ns() so that it can be made a noop depending only on CONFIG_SYSFS regardless of the planned CONFIG_KERNFS. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()Tejun Heo2014-02-071-9/+0
| | | | | | | | | | | | | | | | | | All device_schedule_callback_owner() users are converted to use device_remove_file_self(). Remove now unused {sysfs|device}_schedule_callback_owner(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappersTejun Heo2014-02-071-0/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sometimes it's necessary to implement a node which wants to delete nodes including itself. This isn't straightforward because of kernfs active reference. While a file operation is in progress, an active reference is held and kernfs_remove() waits for all such references to drain before completing. For a self-deleting node, this is a deadlock as kernfs_remove() ends up waiting for an active reference that itself is sitting on top of. This currently is worked around in the sysfs layer using sysfs_schedule_callback() which makes such removals asynchronous. While it works, it's rather cumbersome and inherently breaks synchronicity of the operation - the file operation which triggered the operation may complete before the removal is finished (or even started) and the removal may fail asynchronously. If a removal operation is immmediately followed by another operation which expects the specific name to be available (e.g. removal followed by rename onto the same name), there's no way to make the latter operation reliable. The thing is there's no inherent reason for this to be asynchrnous. All that's necessary to do this synchronous is a dedicated operation which drops its own active ref and deactivates self. This patch implements kernfs_remove_self() and its wrappers in sysfs and driver core. kernfs_remove_self() is to be called from one of the file operations, drops the active ref the task is holding, removes the self node, and restores active ref to the dead node so that the ref is balanced afterwards. __kernfs_remove() is updated so that it takes an early exit if the target node is already fully removed so that the active ref restored by kernfs_remove_self() after removal doesn't confuse the deactivation path. This makes implementing self-deleting nodes very easy. The normal removal path doesn't even need to be changed to use kernfs_remove_self() for the self-deleting node. The method can invoke kernfs_remove_self() on itself before proceeding the normal removal path. kernfs_remove() invoked on the node by the normal deletion path will simply be ignored. This will replace sysfs_schedule_callback(). A subtle feature of sysfs_schedule_callback() is that it collapses multiple invocations - even if multiple removals are triggered, the removal callback is run only once. An equivalent effect can be achieved by testing the return value of kernfs_remove_self() - only the one which gets %true return value should proceed with actual deletion. All other instances of kernfs_remove_self() will wait till the enclosing kernfs operation which invoked the winning instance of kernfs_remove_self() finishes and then return %false. This trivially makes all users of kernfs_remove_self() automatically show correct synchronous behavior even when there are multiple concurrent operations - all "echo 1 > delete" instances will finish only after the whole operation is completed by one of the instances. Note that manipulation of active ref is implemented in separate public functions - kernfs_[un]break_active_protection(). kernfs_remove_self() is the only user at the moment but this will be used to cater to more complex cases. v2: For !CONFIG_SYSFS, dummy version kernfs_remove_self() was missing and sysfs_remove_file_self() had incorrect return type. Fix it. Reported by kbuild test bot. v3: kernfs_[un]break_active_protection() separated out from kernfs_remove_self() and exposed as public API. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "kernfs, sysfs, driver-core: implement kernfs_remove_self() and its ↵Greg Kroah-Hartman2014-01-131-7/+0
| | | | | | | | | | | | | | | | | | | wrappers" This reverts commit 1ae06819c77cff1ea2833c94f8c093fe8a5c79db. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Revert "sysfs, driver-core: remove unused ↵Greg Kroah-Hartman2014-01-131-0/+9
| | | | | | | | | | | | | | | | | {sysfs|device}_schedule_callback_owner()" This reverts commit d1ba277e79889085a2faec3b68b91ce89c63f888. Tejun writes: I'm sorry but can you please revert the whole series? get_active() waiting while a node is deactivated has potential to lead to deadlock and that deactivate/reactivate interface is something fundamentally flawed and that cgroup will have to work with the remove_self() like everybody else. IOW, I think the first posting was correct. Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()Tejun Heo2014-01-101-9/+0
| | | | | | | | | All device_schedule_callback_owner() users are converted to use device_remove_file_self(). Remove now unused {sysfs|device}_schedule_callback_owner(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappersTejun Heo2014-01-101-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sometimes it's necessary to implement a node which wants to delete nodes including itself. This isn't straightforward because of kernfs active reference. While a file operation is in progress, an active reference is held and kernfs_remove() waits for all such references to drain before completing. For a self-deleting node, this is a deadlock as kernfs_remove() ends up waiting for an active reference that itself is sitting on top of. This currently is worked around in the sysfs layer using sysfs_schedule_callback() which makes such removals asynchronous. While it works, it's rather cumbersome and inherently breaks synchronicity of the operation - the file operation which triggered the operation may complete before the removal is finished (or even started) and the removal may fail asynchronously. If a removal operation is immmediately followed by another operation which expects the specific name to be available (e.g. removal followed by rename onto the same name), there's no way to make the latter operation reliable. The thing is there's no inherent reason for this to be asynchrnous. All that's necessary to do this synchronous is a dedicated operation which drops its own active ref and deactivates self. This patch implements kernfs_remove_self() and its wrappers in sysfs and driver core. kernfs_remove_self() is to be called from one of the file operations, drops the active ref and deactivates using __kernfs_deactivate_self(), removes the self node, and restores active ref to the dead node using __kernfs_reactivate_self() so that the ref is balanced afterwards. __kernfs_remove() is updated so that it takes an early exit if the target node is already fully removed so that the active ref restored by kernfs_remove_self() after removal doesn't confuse the deactivation path. This makes implementing self-deleting nodes very easy. The normal removal path doesn't even need to be changed to use kernfs_remove_self() for the self-deleting node. The method can invoke kernfs_remove_self() on itself before proceeding the normal removal path. kernfs_remove() invoked on the node by the normal deletion path will simply be ignored. This will replace sysfs_schedule_callback(). A subtle feature of sysfs_schedule_callback() is that it collapses multiple invocations - even if multiple removals are triggered, the removal callback is run only once. An equivalent effect can be achieved by testing the return value of kernfs_remove_self() - only the one which gets %true return value should proceed with actual deletion. All other instances of kernfs_remove_self() will wait till the enclosing kernfs operation which invoked the winning instance of kernfs_remove_self() finishes and then return %false. This trivially makes all users of kernfs_remove_self() automatically show correct synchronous behavior even when there are multiple concurrent operations - all "echo 1 > delete" instances will finish only after the whole operation is completed by one of the instances. v2: For !CONFIG_SYSFS, dummy version kernfs_remove_self() was missing and sysfs_remove_file_self() had incorrect return type. Fix it. Reported by kbuild test bot. v3: Updated to use __kernfs_{de|re}activate_self(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: s/sysfs_dirent/kernfs_node/ and rename its friends accordinglyTejun Heo2013-12-111-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kernfs has just been separated out from sysfs and we're already in full conflict mode. Nothing can make the situation any worse. Let's take the chance to name things properly. This patch performs the following renames. * s/sysfs_elem_dir/kernfs_elem_dir/ * s/sysfs_elem_symlink/kernfs_elem_symlink/ * s/sysfs_elem_attr/kernfs_elem_file/ * s/sysfs_dirent/kernfs_node/ * s/sd/kn/ in kernfs proper * s/parent_sd/parent/ * s/target_sd/target/ * s/dir_sd/parent/ * s/to_sysfs_dirent()/rb_to_kn()/ * misc renames of local vars when they conflict with the above Because md, mic and gpio dig into sysfs details, this patch ends up modifying them. All are sysfs_dirent renames and trivial. While we can avoid these by introducing a dummy wrapping struct sysfs_dirent around kernfs_node, given the limited usage outside kernfs and sysfs proper, I don't think such workaround is called for. This patch is strictly rename only and doesn't introduce any functional difference. - mic / gpio renames were missing. Spotted by kbuild test robot. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Neil Brown <neilb@suse.de> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Ashutosh Dixit <ashutosh.dixit@intel.com> Cc: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, kernfs: introduce kernfs[_find_and]_get() and kernfs_put()Tejun Heo2013-11-291-21/+14
| | | | | | | | | | | | | | | | | | | | | | | Introduce kernfs interface for finding, getting and putting sysfs_dirents. * sysfs_find_dirent() is renamed to kernfs_find_ns() and lockdep assertion for sysfs_mutex is added. * sysfs_get_dirent_ns() is renamed to kernfs_find_and_get(). * Macro inline dancing around __sysfs_get/put() are removed and kernfs_get/put() are made proper functions implemented in fs/sysfs/dir.c. While the conversions are mostly equivalent, there's one difference - kernfs_get() doesn't return the input param as its return value. This change is intentional. While passing through the input increases writability in some areas, it is unnecessary and has been shown to cause confusion regarding how the last ref is handled. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, kernfs: introduce kernfs_notify()Tejun Heo2013-11-291-4/+5
| | | | | | | | | | | | | | | | Introduce kernfs interface to wake up poll(2) which takes and returns sysfs_dirents. sysfs_notify_dirent() is renamed to kernfs_notify() and sysfs_notify() is updated so that it doesn't directly grab sysfs_mutex but acquires the target sysfs_dirents using sysfs_get_dirent(). sysfs_notify_dirent() is reimplemented as a dumb inline wrapper around kernfs_notify(). This patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, kernfs: introduce kernfs_create_dir[_ns]()Tejun Heo2013-11-291-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | Introduce kernfs interface to manipulate a directory which takes and returns sysfs_dirents. create_dir() is renamed to kernfs_create_dir_ns() and its argumantes and return value are updated. create_dir() usages are replaced with kernfs_create_dir_ns() and sysfs_create_subdir() usages are replaced with kernfs_create_dir(). Dup warnings are handled explicitly by sysfs users of the kernfs interface. sysfs_enable_ns() is renamed to kernfs_enable_ns(). This patch doesn't introduce any behavior changes. v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS. v3: kernfs_enable_ns() added. v4: Refreshed on top of "sysfs: drop kobj_ns_type handling, take #2" so that this patch removes sysfs_enable_ns(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, kernfs: add skeletons for kernfsTejun Heo2013-11-271-2/+1
| | | | | | | | | | | | | | | | | | | | Core sysfs implementation will be separated into kernfs so that it can be used by other non-kobject users. This patch creates fs/kernfs/ directory and makes boilerplate changes. kernfs interface will be directly based on sysfs_dirent and its forward declaration is moved to include/linux/kernfs.h which is included from include/linux/sysfs.h. sysfs core implementation will be gradually separated out and moved to kernfs. This patch doesn't introduce any functional changes. v2: mount.c added. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: drop kobj_ns_type handling, take #2Tejun Heo2013-11-271-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The way namespace tags are implemented in sysfs is more complicated than necessary. As each tag is a pointer value and required to be non-NULL under a namespace enabled parent, there's no need to record separately what type each tag is. If multiple namespace types are needed, which currently aren't, we can simply compare the tag to a set of allowed tags in the superblock assuming that the tags, being pointers, won't have the same value across multiple types. This patch rips out kobj_ns_type handling from sysfs. sysfs now has an enable switch to turn on namespace under a node. If enabled, all children are required to have non-NULL namespace tags and filtered against the super_block's tag. kobject namespace determination is now performed in lib/kobject.c::create_dir() making sysfs_read_ns_type() unnecessary. The sanity checks are also moved. create_dir() is restructured to ease such addition. This removes most kobject namespace knowledge from sysfs proper which will enable proper separation and layering of sysfs. This is the second try. The first one was cb26a311578e ("sysfs: drop kobj_ns_type handling") which tried to automatically enable namespace if there are children with non-NULL namespace tags; however, it was broken for symlinks as they should inherit the target's tag iff namespace is enabled in the parent. This led to namespace filtering enabled incorrectly for wireless net class devices through phy80211 symlinks and thus network configuration failure. a1212d278c05 ("Revert "sysfs: drop kobj_ns_type handling"") reverted the commit. This shouldn't introduce any behavior changes, for real. v2: Dummy implementation of sysfs_enable_ns() for !CONFIG_SYSFS was missing and caused build failure. Reported by kbuild test robot. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: clean up sysfs_get_dirent()Tejun Heo2013-09-261-7/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The pre-existing sysfs interfaces which take explicit namespace argument are weird in that they place the optional @ns in front of @name which is contrary to the established convention. For example, we end up forcing vast majority of sysfs_get_dirent() users to do sysfs_get_dirent(parent, NULL, name), which is silly and error-prone especially as @ns and @name may be interchanged without causing compilation warning. This renames sysfs_get_dirent() to sysfs_get_dirent_ns() and swap the positions of @name and @ns, and sysfs_get_dirent() is now a wrapper around sysfs_get_dirent_ns(). This makes confusions a lot less likely. There are other interfaces which take @ns before @name. They'll be updated by following patches. This patch doesn't introduce any functional changes. v2: EXPORT_SYMBOL_GPL() wasn't updated leading to undefined symbol error on module builds. Reported by build test robot. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: remove ktype->namespace() invocations in symlink codeTejun Heo2013-09-261-4/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | There's no reason for sysfs to be calling ktype->namespace(). It is backwards, obfuscates what's going on and unnecessarily tangles two separate layers. There are two places where symlink code calls ktype->namespace(). * sysfs_do_create_link_sd() calls it to find out the namespace tag of the target directory. Unless symlinking races with cross-namespace renaming, this equals @target_sd->s_ns. * sysfs_rename_link() uses it to find out the new namespace to rename to and the new namespace can be different from the existing one. The function is renamed to sysfs_rename_link_ns() with an explicit @ns argument and the ktype->namespace() invocation is shifted to the device layer. While this patch replaces ktype->namespace() invocation with the recorded result in @target_sd, this shouldn't result in any behvior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: remove ktype->namespace() invocations in directory codeTejun Heo2013-09-261-8/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For some unrecognizable reason, namespace information is communicated to sysfs through ktype->namespace() callback when there's *nothing* which needs the use of a callback. The whole sequence of operations is completely synchronous and sysfs operations simply end up calling back into the layer which just invoked it in order to find out the namespace information, which is completely backwards, obfuscates what's going on and unnecessarily tangles two separate layers. This patch doesn't remove ktype->namespace() but shifts its handling to kobject layer. We probably want to get rid of the callback in the long term. This patch adds an explicit param to sysfs_{create|rename|move}_dir() and renames them to sysfs_{create|rename|move}_dir_ns(), respectively. ktype->namespace() invocations are moved to the calling sites of the above functions. A new helper kboject_namespace() is introduced which directly tests kobj_ns_type_operations->type which should give the same result as testing sysfs_fs_type(parent_sd) and returns @kobj's namespace tag as necessary. kobject_namespace() is extern as it will be used from another file in the following patches. This patch should be an equivalent conversion without any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: make attr namespace interface less convolutedTejun Heo2013-09-261-8/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sysfs ns (namespace) implementation became more convoluted than necessary while trying to hide ns information from visible interface. The relatively recent attr ns support is a good example. * attr ns tag is determined by sysfs_ops->namespace() callback while dir tag is determined by kobj_type->namespace(). The placement is arbitrary. * Instead of performing operations with explicit ns tag, the namespace callback is routed through sysfs_attr_ns(), sysfs_ops->namespace(), class_attr_namespace(), class_attr->namespace(). It's not simpler in any sense. The only thing this convolution does is traversing the whole stack backwards. The namespace callbacks are unncessary because the operations involved are inherently synchronous. The information can be provided in in straight-forward top-down direction and reversing that direction is unnecessary and against basic design principles. This backward interface is unnecessarily convoluted and hinders properly separating out sysfs from driver model / kobject for proper layering. This patch updates attr ns support such that * sysfs_ops->namespace() and class_attr->namespace() are dropped. * sysfs_{create|remove}_file_ns(), which take explicit @ns param, are added and sysfs_{create|remove}_file() are now simple wrappers around the ns aware functions. * ns handling is dropped from sysfs_chmod_file(). Nobody uses it at this point. sysfs_chmod_file_ns() can be added later if necessary. * Explicit @ns is propagated through class_{create|remove}_file_ns() and netdev_class_{create|remove}_file_ns(). * driver/net/bonding which is currently the only user of attr namespace is updated to use netdev_class_{create|remove}_file_ns() with @bh->net as the ns tag instead of using the namespace callback. This patch should be an equivalent conversion without any functional difference. It makes the code easier to follow, reduces lines of code a bit and helps proper separation and layering. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kay Sievers <kay@vrfy.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: sysfs_create_groups returns a value.Greg Kroah-Hartman2013-08-281-0/+1
| | | | | | | | | When I included the "empty" function for sysfs_create_groups() when CONFIG_SYSFS=n, I forgot to return a value for it, so things blew up the build. This patch fixes that, stupid me. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: add sysfs_create/remove_groups for when SYSFS is not enabledGreg Kroah-Hartman2013-08-271-0/+10
| | | | | | | We need these functions for when CONFIG_SYSFS=n. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: create __ATTR_WO()Greg Kroah-Hartman2013-08-231-0/+5
| | | | | | | This creates the macro __ATTR_WO() for write-only attributes, instead of having to "open define" them. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs.h: remove attr_name() macroGreg Kroah-Hartman2013-08-221-2/+0
| | | | | | | | | | | Gotta love a macro that doesn't reduce the typing you have to do. Also, only the driver core, and one network driver uses this. The driver core functions will be going away soon, and I'll convert the network driver soon to not need this as well, so delete it for now before anyone else gets some bright ideas and wants to use it. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: fix up minor coding style issues in sysfs.hGreg Kroah-Hartman2013-08-211-6/+6
| | | | | | | As long as we are cleaning up sysfs coding style issues, don't forget the main sysfs.h file, so fix up the space issues there as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: add sysfs_create/remove_groups()Greg Kroah-Hartman2013-08-211-0/+4
| | | | | | | | | These functions are being open-coded in 3 different places in the driver core, and other driver subsystems will want to start doing this as well, so move it to the sysfs core to keep it all in one place, where we know it is written properly. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs.h: fix __BIN_ATTR_RW()Greg Kroah-Hartman2013-08-201-1/+1
| | | | | | | | | | __BIN_ATTR_RW() wasn't passing in the _size field. As it would break the build if this macro was ever used, it's obvious no one had ever tried to use it before. Fix it so that it can be used. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: use file mode defines from stat.hOliver Schinagl2013-07-161-8/+9
| | | | | | | | With the last patches stat.h was included to the header, and thus those permission defines should be used. Signed-off-by: Oliver Schinagl <oliver@schinagl.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: add more helper macro's for (bin_)attribute(_groups)Oliver Schinagl2013-07-161-13/+38
| | | | | | | | With the recent changes to sysfs there's various helper macro's. However there's no RW, RO BIN_ helper macro's. This patch adds them. Signed-off-by: Oliver Schinagl <oliver@schinagl.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: add support for binary attributes in groupsGreg Kroah-Hartman2013-07-161-2/+2
| | | | | | | | | | | | | groups should be able to support binary attributes, just like it supports "normal" attributes. This lets us only handle one type of structure, groups, throughout the driver core and subsystems, making binary attributes a "full fledged" part of the driver model, and not something just "tacked on". Reported-by: Oliver Schinagl <oliver@schinagl.nl> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs.h: add BIN_ATTR macroGreg Kroah-Hartman2013-07-161-0/+9
| | | | | | | | | This makes it easier to create static binary attributes, which is needed in a number of drivers, instead of "open coding" them. Reviewed-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs.h: add ATTRIBUTE_GROUPS() macroGreg Kroah-Hartman2013-07-161-0/+9
| | | | | | | | | | To make it easier for driver subsystems to work with attribute groups, create the ATTRIBUTE_GROUPS macro to remove some of the repetitive typing for the most common use for attribute groups. Reviewed-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs.h: add __ATTR_RW() macroGreg Kroah-Hartman2013-07-161-0/+2
| | | | | | | | | A number of parts of the kernel created their own version of this, might as well have the sysfs core provide it instead. Reviewed-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: Functions for adding/removing symlinks to/from attribute groupsRafael J. Wysocki2013-01-251-0/+16
| | | | | | | | | | | | | | | | | The most convenient way to expose ACPI power resources lists of a device is to put symbolic links to sysfs directories representing those resources into special attribute groups in the device's sysfs directory. For this purpose, it is necessary to be able to add symbolic links to attribute groups. For this reason, add sysfs helper functions for adding/removing symbolic links to/from attribute groups, sysfs_add_link_to_group() and sysfs_remove_link_from_group(), respectively. This change set includes a build fix from David Rientjes. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>