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* kernfs: implement kernfs_get_parent(), kernfs_name/path() and friendsTejun Heo2014-02-071-31/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | kernfs_node->parent and ->name are currently marked as "published" indicating that kernfs users may access them directly; however, those fields may get updated by kernfs_rename[_ns]() and unrestricted access may lead to erroneous values or oops. Protect ->parent and ->name updates with a irq-safe spinlock kernfs_rename_lock and implement the following accessors for these fields. * kernfs_name() - format the node's name into the specified buffer * kernfs_path() - format the node's path into the specified buffer * pr_cont_kernfs_name() - pr_cont a node's name (doesn't need buffer) * pr_cont_kernfs_path() - pr_cont a node's path (doesn't need buffer) * kernfs_get_parent() - pin and return a node's parent All can be called under any context. The recursive sysfs_pathname() in fs/sysfs/dir.c is replaced with kernfs_path() and sysfs_rename_dir_ns() is updated to use kernfs_get_parent() instead of dereferencing parent directly. v2: Dummy definition of kernfs_path() for !CONFIG_KERNFS was missing static inline making it cause a lot of build warnings. Add it. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: add @mode to kernfs_create_dir[_ns]()Tejun Heo2013-12-171-1/+2
| | | | | | | | | | | | | | sysfs assumed 0755 for all newly created directories and kernfs inherited it. This assumption is unnecessarily restrictive and inconsistent with kernfs_create_file[_ns](). This patch adds @mode parameter to kernfs_create_dir[_ns]() and update uses in sysfs accordingly. Among others, this will be useful for implementations of the planned ->mkdir() method. This patch doesn't introduce any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: s/sysfs/kernfs/ in constantsTejun Heo2013-12-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | 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_DIR/KERNFS_DIR/ * s/SYSFS_KOBJ_ATTR/KERNFS_FILE/ * s/SYSFS_KOBJ_LINK/KERNFS_LINK/ * s/SYSFS_{TYPE_FLAGS}/KERNFS_{TYPE_FLAGS}/ * s/SYSFS_FLAG_{FLAG}/KERNFS_{FLAG}/ * s/sysfs_type()/kernfs_type()/ * s/SD_DEACTIVATED_BIAS/KN_DEACTIVATED_BIAS/ This patch is strictly rename only and doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: drop s_ prefix from kernfs_node membersTejun Heo2013-12-111-6/+6
| | | | | | | | | | | | | | | | | 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. s_ prefix for kernfs members is used inconsistently and a misnomer now. It's not like kernfs_node is used widely across the kernel making the ability to grep for the members particularly useful. Let's just drop the prefix. This patch is strictly rename only and doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kernfs: s/sysfs_dirent/kernfs_node/ and rename its friends accordinglyTejun Heo2013-12-111-33/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 sysfs_root_sdTejun Heo2013-11-291-2/+2
| | | | | | | | | | | | | Currently, it's assumed that there's a single kernfs hierarchy in the system anchored at sysfs_root which is defined as a global struct. To allow other users of kernfs, this will be made dynamic. Introduce a new global variable sysfs_root_sd which points to &sysfs_root and convert all &sysfs_root users. This patch doesn't introduce any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, kernfs: move dir core code to fs/kernfs/dir.cTejun Heo2013-11-291-986/+0
| | | | | | | | | | | | | | | Move core dir code to fs/kernfs/dir.c. fs/sysfs/dir.c now only contains sysfs_warn_dup() and sysfs wrappers around kernfs interfaces. The respective declarations in fs/sysfs/sysfs.h are moved to fs/kernfs/kernfs-internal.h. This is pure relocation. v2: sysfs_symlink_target_lock was mistakenly relocated to kernfs. It should remain with sysfs. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, kernfs: introduce kernfs[_find_and]_get() and kernfs_put()Tejun Heo2013-11-291-50/+67
| | | | | | | | | | | | | | | | | | | | | | | 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: revamp sysfs_dirent active_ref lockdep annotationTejun Heo2013-11-291-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, sysfs_dirent active_ref lockdep annotation uses attribute->[s]key as the lockdep key, which forces kernfs_create_file_ns() to assume that sysfs_dirent->priv is pointing to a struct attribute which may not be true for non-sysfs users. This patch restructures the lockdep annotation such that * kernfs_ops contains lockdep_key which is used by default for files created kernfs_create_file_ns(). * kernfs_create_file_ns_key() is introduced which takes an extra @key argument. The created file will use the specified key for active_ref lockdep annotation. If NULL is specified, lockdep for the file is disabled. * sysfs_add_file_mode_ns() is updated to use kernfs_create_file_ns_key() with the appropriate key from the attribute or NULL if ignore_lockdep is set. This makes the lockdep annotation properly contained in kernfs while allowing sysfs to cleanly keep its current behavior. This patch doesn't introduce any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, kernfs: remove sysfs_add_one()Tejun Heo2013-11-291-37/+4
| | | | | | | | | | | | | | sysfs_add_one() is a wrapper around __sysfs_add_one() which prints out duplicate name warning if __sysfs_add_one() fails with -EEXIST. The previous kernfs conversions moved all dup warnings to sysfs interface functions and sysfs_add_one() doesn't have any user left. Remove sysfs_add_one() and update __sysfs_add_one() to take its name. This patch doesn't make any functional 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 Heo2013-11-291-24/+30
| | | | | | | | | | | | | | | | | | | | | | | | | 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: replace sysfs_dirent->s_dir.kobj and ->s_attr.[bin_]attr with ↵Tejun Heo2013-11-291-1/+1
| | | | | | | | | | | | | | | | | | | | | ->priv A directory sysfs_dirent points to the associated kobj. A regular or bin file points to the associated [bin_]attribute. This patch replaces sysfs_dirent->s_dir.kobj and ->s_attr.[bin_]attr with void * ->priv. This is to prepare for kernfs interface so that sysfs can specify the private data in the same way for directories and files. This lower debuggability but not by much - the whole thing was overlaid in a union anyway. If debuggability becomes an issue, we can later add ->priv accessors which explicitly check for the sysfs_dirent type and performs casting. This patch doesn't introduce any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, kernfs: introduce kernfs_rename[_ns]()Tejun Heo2013-11-271-8/+15
| | | | | | | | | | | | | Introduce kernfs rename interface, krenfs_rename[_ns](). This is just rename of sysfs_rename(). No functional changes. Function comment is added to kernfs_rename_ns() and @new_parent_sd is renamed to @new_parent for consistency with other kernfs interfaces. v2: Dummy implementation for !CONFIG_SYSFS updated to return -ENOSYS. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs, kernfs: introduce kernfs_remove[_by_name[_ns]]()Tejun Heo2013-11-271-10/+10
| | | | | | | | | | | | | | Introduce kernfs removal interfaces - kernfs_remove() and kernfs_remove_by_name[_ns](). These are just renames of sysfs_remove() and sysfs_hash_and_remove(). No functional changes. v2: Dummy kernfs_remove_by_name_ns() for !CONFIG_SYSFS updated to return -ENOSYS instead of 0. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: make __sysfs_add_one() fail if the parent isn't a directoryTejun Heo2013-11-271-0/+3
| | | | | | | | | | | Currently the kobject based interface guarantees that a parent sysfs_dirent is always a directory; however, the planned kernfs interface will be directly based on sysfs_dirents and the caller may specify non-directory node as the parent. Add an explicit check in __sysfs_add_one() so that such attempts fail with -EINVAL. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: drop kobj_ns_type handling, take #2Tejun Heo2013-11-271-56/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Revert "sysfs: drop kobj_ns_type handling"Linus Torvalds2013-11-071-24/+64
| | | | | | | | | | | | | | This reverts commit cb26a311578e67769e92a39a0a63476533cb7e12. It mysteriously causes NetworkManager to not find the wireless device for me. As far as I can tell, Tejun *meant* for this commit to not make any semantic changes, but there clearly are some. So revert it, taking into account some of the calling convention changes that happened in this area in subsequent commits. Cc: Tejun Heo <tj@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysfs: rename sysfs_assoc_lock and explain what it's aboutTejun Heo2013-11-011-3/+15
| | | | | | | | | | | | | | | | | | | | | | sysfs_assoc_lock is an odd piece of locking. In general, whoever owns a kobject is responsible for synchronizing sysfs operations and sysfs proper assumes that, for example, removal won't race with any other operation; however, this doesn't work for symlinking because an entity performing symlink doesn't usually own the target kobject and thus has no control over its removal. sysfs_assoc_lock synchronizes symlink operations against kobj->sd disassociation so that symlink code doesn't end up dereferencing already freed sysfs_dirent by racing with removal of the target kobject. This is quite obscure and the generic name of the lock and lack of comments make it difficult to understand its role. Let's rename it to sysfs_symlink_target_lock and add comments explaining what's going on. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: separate out dup filename warning into a separate functionTejun Heo2013-10-291-11/+19
| | | | | | | | | | | Separate out sysfs_warn_dup() out of sysfs_add_one(). This will help separating out the core sysfs functionalities into kernfs so that it can be used by non-sysfs users too. This doesn't make any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: move sysfs_hash_and_remove() to fs/sysfs/dir.cTejun Heo2013-10-291-1/+37
| | | | | | | | | | | Most removal related logic is implemented in fs/sysfs/dir.c. Move sysfs_hash_and_remove() to fs/sysfs/dir.c so that __sysfs_remove() doesn't have to be public. This is pure relocation. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: make sysfs_file_ops() follow ignore_lockdep flagTejun Heo2013-10-141-20/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 375b611e60 ("sysfs: remove sysfs_buffer->ops") introduced sysfs_file_ops() which determines the associated file operation of a given sysfs_dirent. As file ops access should be protected by an active reference, the new function includes a lockdep assertion on the sysfs_dirent; unfortunately, I forgot to take attr->ignore_lockdep flag into account and the lockdep assertion trips spuriously for files which opt out from active reference lockdep checking. # cat /sys/devices/pci0000:00/0000:00:01.2/usb1/authorized ------------[ cut here ]------------ WARNING: CPU: 1 PID: 540 at /work/os/work/fs/sysfs/file.c:79 sysfs_file_ops+0x4e/0x60() Modules linked in: CPU: 1 PID: 540 Comm: cat Not tainted 3.11.0-work+ #3 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 0000000000000009 ffff880016205c08 ffffffff81ca0131 0000000000000000 ffff880016205c40 ffffffff81096d0d ffff8800166cb898 ffff8800166f6f60 ffffffff8125a220 ffff880011ab1ec0 ffff88000aff0c78 ffff880016205c50 Call Trace: [<ffffffff81ca0131>] dump_stack+0x4e/0x82 [<ffffffff81096d0d>] warn_slowpath_common+0x7d/0xa0 [<ffffffff81096dea>] warn_slowpath_null+0x1a/0x20 [<ffffffff8125994e>] sysfs_file_ops+0x4e/0x60 [<ffffffff8125a274>] sysfs_open_file+0x54/0x300 [<ffffffff811df612>] do_dentry_open.isra.17+0x182/0x280 [<ffffffff811df820>] finish_open+0x30/0x40 [<ffffffff811f0623>] do_last+0x503/0xd90 [<ffffffff811f0f6b>] path_openat+0xbb/0x6d0 [<ffffffff811f23ba>] do_filp_open+0x3a/0x90 [<ffffffff811e09a9>] do_sys_open+0x129/0x220 [<ffffffff811e0abe>] SyS_open+0x1e/0x20 [<ffffffff81caf3c2>] system_call_fastpath+0x16/0x1b ---[ end trace aa48096b111dafdb ]--- Rename fs/sysfs/dir.c::ignore_lockdep() to sysfs_ignore_lockdep() and move it to fs/sysfs/sysfs.h and make sysfs_file_ops() skip lockdep assertion if sysfs_ignore_lockdep() is true. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: merge regular and bin file handlingTejun Heo2013-10-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the previous changes, sysfs regular file code is ready to handle bin files too. This patch makes bin files share the regular file path. * sysfs_create/remove_bin_file() are moved to fs/sysfs/file.c. * sysfs_init_inode() is updated to use the new sysfs_bin_operations instead of bin_fops for bin files. * fs/sysfs/bin.c and the related pieces are removed. This patch shouldn't introduce any behavior difference to bin file accesses. Overall, this unification reduces the amount of duplicate logic, makes behaviors more consistent and paves the road for building simpler and more versatile interface which will allow other subsystems to make use of sysfs for their pseudo filesystems. v2: Stale fs/sysfs/bin.c reference dropped from Documentation/DocBook/filesystems.tmpl. Reported by kbuild test robot. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Kay Sievers <kay@vrfy.org> Cc: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: copy bin mmap support from fs/sysfs/bin.c to fs/sysfs/file.cTejun Heo2013-10-051-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | sysfs bin file handling will be merged into the regular file support. This patch copies mmap support from bin so that fs/sysfs/file.c can handle mmapping bin files. The code is copied mostly verbatim with the following updates. * ->mmapped and ->vm_ops are added to sysfs_open_file and bin_buffer references are replaced with sysfs_open_file ones. * Symbols are prefixed with sysfs_. * sysfs_unmap_bin_file() grabs sysfs_open_dirent and traverses ->files. Invocation of this function is added to sysfs_addrm_finish(). * sysfs_bin_mmap() is added to sysfs_bin_operations. This is a preparation and the new mmap path isn't used yet. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: introduce [__]sysfs_remove()Tejun Heo2013-10-031-23/+24
| | | | | | | | | | | | | Given a sysfs_dirent, there is no reason to have multiple versions of removal functions. A function which removes the specified sysfs_dirent and its descendants is enough. This patch intorduces [__}sysfs_remove() which replaces all internal variations of removal functions. This will be the only removal function in the planned new sysfs_dirent based interface. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: make __sysfs_remove_dir() recursiveTejun Heo2013-10-031-11/+64
| | | | | | | | | | | | | | | | | | | | | Currently, sysfs directory removal is inconsistent in that it would remove any files directly under it but wouldn't recurse into directories. Thanks to group subdirectories, this doesn't even match with kobject boundaries. sysfs is in the process of being separated out so that it can be used by multiple subsystems and we want to have a consistent behavior - either removal of a sysfs_dirent should remove every descendant entries or none instead of something inbetween. This patch implements proper recursive removal in __sysfs_remove_dir(). The function now walks its subtree in a post-order walk to remove all descendants. This is a behavior change but kobject / driver layer, which currently is the only consumer, has already been updated to handle duplicate removal attempts, so nothing should be broken after this change. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* kobject: grab an extra reference on kobject->sd to allow duplicate deletesTejun Heo2013-10-031-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | sysfs currently has a rather weird behavior regarding removals. A directory removal would delete all files directly under it but wouldn't recurse into subdirectories, which, while a bit inconsistent, seems to make sense at the first glance as each directory is supposedly associated with a kobject and each kobject can take care of the directory deletion; however, this doesn't really hold as we have groups which can be directories without a kobject associated with it and require explicit deletions. We're in the process of separating out sysfs from kboject / driver core and want a consistent behavior. A removal should delete either only the specified node or everything under it. I think it is helpful to support recursive atomic removal and later patches will implement it. Such change means that a sysfs_dirent associated with kobject may be deleted before the kobject itself is removed if one of its ancestor gets removed before it. As sysfs_remove_dir() puts the base ref, we may end up with dangling pointer on descendants. This can be solved by holding an extra reference on the sd from kobject. Acquire an extra reference on the associated sysfs_dirent on directory creation and put it after removal. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: remove sysfs_addrm_cxt->parent_sdTejun Heo2013-10-031-25/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | sysfs_addrm_start/finish() enclose sysfs_dirent additions and deletions and sysfs_addrm_cxt is used to record information necessary to finish the operations. Currently, sysfs_addrm_start() takes @parent_sd, records it in sysfs_addrm_cxt, and assumes that all operations in the block are performed under that @parent_sd. This assumption has been fine until now but we want to make some operations behave recursively and, while having @parent_sd recorded in sysfs_addrm_cxt doesn't necessarily prevents that, it becomes confusing. This patch removes sysfs_addrm_cxt->parent_sd and makes sysfs_add_one() take an explicit @parent_sd parameter. Note that sysfs_remove_one() doesn't need the extra argument as its parent is always known from the target @sd. While at it, add __acquires/releases() notations to sysfs_addrm_start/finish() respectively. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: @name comes before @nsTejun Heo2013-09-261-22/+23
| | | | | | | | | | | | | | | | | | | | | | | | | Some internal sysfs functions 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. This is confusing and error-prone especially as @ns and @name may be interchanged without causing compilation warning. Swap the positions of @name and @ns in the following internal functions. sysfs_find_dirent() sysfs_rename() sysfs_hash_and_remove() sysfs_name_hash() sysfs_name_compare() create_dir() This patch doesn't introduce any functional changes. 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: clean up sysfs_get_dirent()Tejun Heo2013-09-261-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: drop kobj_ns_type handlingTejun Heo2013-09-261-65/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 or where namespace is enabled. 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. Also, whether to filter by namespace tag or not can be trivially determined by whether the node has any tagged children or not. This patch rips out kobj_ns_type handling from sysfs. sysfs no longer cares whether specific type of namespace is enabled or not. If a sysfs_dirent has a non-NULL tag, the parent is marked as needing namespace filtering and the value is tested against the allowed set of tags for the superblock (currently only one but increasing this number isn't difficult) and the sysfs_dirent is ignored if it doesn't match. This removes most kobject namespace knowledge from sysfs proper which will enable proper separation and layering of sysfs. The namespace sanity checks in fs/sysfs/dir.c are replaced by the new sanity check in kobject_namespace(). As this is the only place ktype->namespace() is called for sysfs, this doesn't weaken the sanity check significantly. I omitted converting the sanity check in sysfs_do_create_link_sd(). While the check can be shifted to upper layer, mistakes there are well contained and should be easily visible anyway. 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 Heo2013-09-261-15/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: drop semicolon from to_sysfs_dirent() definitionTejun Heo2013-09-261-1/+1
| | | | | | | | | The expansion of to_sysfs_dirent() contains an unncessary trailing semicolon making it impossible to use in the middle of statements. Drop it. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: use check_submounts_and_drop()Miklos Szeredi2013-09-051-12/+8
| | | | | | | | | | | | | | Do have_submounts(), shrink_dcache_parent() and d_drop() atomically. check_submounts_and_drop() can deal with negative dentries and non-directories as well. Non-directories can also be mounted on. And just like directories we don't want these to disappear with invalidation. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* sysfs: dir.c: fix up odd do/while indentationGreg Kroah-Hartman2013-08-211-7/+8
| | | | | | This fixes up the odd do/while after an if statement warning in dir.c Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: fix up 80 column coding style issuesGreg Kroah-Hartman2013-08-211-1/+3
| | | | | | This fixes up the 80 column coding style issues in the sysfs .c files. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: fix up space coding style issuesGreg Kroah-Hartman2013-08-211-10/+10
| | | | | | | This fixes up all of the space-related coding style issues for the sysfs code. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: remove trailing whitespaceGreg Kroah-Hartman2013-08-211-1/+1
| | | | | | This removes all trailing whitespace errors in the sysfs code. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'driver-core-3.11-rc1' of ↵Linus Torvalds2013-07-021-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here's the big driver core merge for 3.11-rc1 Lots of little things, and larger firmware subsystem updates, all described in the shortlog. Nice thing here is that we finally get rid of CONFIG_HOTPLUG, after 10+ years, thanks to Stephen Rohtwell (it had been always on for a number of kernel releases, now it's just removed)" * tag 'driver-core-3.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (27 commits) driver core: device.h: fix doc compilation warnings firmware loader: fix another compile warning with PM_SLEEP unset build some drivers only when compile-testing firmware loader: fix compile warning with PM_SLEEP set kobject: sanitize argument for format string sysfs_notify is only possible on file attributes firmware loader: simplify holding module for request_firmware firmware loader: don't export cache_firmware and uncache_firmware drivers/base: Use attribute groups to create sysfs memory files firmware loader: fix compile warning firmware loader: fix build failure with !CONFIG_FW_LOADER_USER_HELPER Documentation: Updated broken link in HOWTO Finally eradicate CONFIG_HOTPLUG driver core: firmware loader: kill FW_ACTION_NOHOTPLUG requests before suspend driver core: firmware loader: don't cache FW_ACTION_NOHOTPLUG firmware Documentation: Tidy up some drivers/base/core.c kerneldoc content. platform_device: use a macro instead of platform_driver_register firmware: move EXPORT_SYMBOL annotations firmware: Avoid deadlock of usermodehelper lock at shutdown dell_rbu: Select CONFIG_FW_LOADER_USER_HELPER explicitly ...
| * sysfs: sysfs_link_sibling(): fix typo in commentWarner Wang2013-05-171-1/+1
| | | | | | | | | | | | | | Fix a typo subling->sibling in the comment of sysfs_link_sibling(). Signed-off-by: Warner Wang <warner.wang@hp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | [readdir] convert sysfsAl Viro2013-06-291-48/+18
|/ | | | | | get rid of the kludges in sysfs_readdir() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* sysfs: check if one entry has been removed before freeingMing Lei2013-04-051-1/+8
| | | | | | | | | | | | | | | | | | | | It might be a kernel disaster if one sysfs entry is freed but still referenced by sysfs tree. Recently Dave and Sasha reported one use-after-free problem on sysfs entry, and the problem has been troubleshooted with help of debug message added in this patch. Given sysfs_get_dirent/sysfs_put are exported APIs, even inside sysfs they are called in many contexts(kobject/attribe add/delete, inode init/drop, dentry lookup/release, readdir, ...), it is healthful to check the removed flag before freeing one entry and dump message if it is freeing without being removed first. Cc: Dave Jones <davej@redhat.com> Cc: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: fix use after free in case of concurrent read/write and readdirMing Lei2013-04-031-4/+11
| | | | | | | | | | | | | | | | | | | The inode->i_mutex isn't hold when updating filp->f_pos in read()/write(), so the filp->f_pos might be read as 0 or 1 in readdir() when there is concurrent read()/write() on this same file, then may cause use after free in readdir(). The bug can be reproduced with Li Zefan's test code on the link: https://patchwork.kernel.org/patch/2160771/ This patch fixes the use after free under this situation. Cc: stable <stable@vger.kernel.org> Reported-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge v3.9-rc5 into driver-core-nextGreg Kroah-Hartman2013-04-011-1/+16
|\ | | | | | | | | | | We want the fixes in here. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * sysfs: handle failure path correctly for readdir()Ming Lei2013-03-201-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In case of 'if (filp->f_pos == 0 or 1)' of sysfs_readdir(), the failure from filldir() isn't handled, and the reference counter of the sysfs_dirent object pointed by filp->private_data will be released without clearing filp->private_data, so use after free bug will be triggered later. This patch returns immeadiately under the situation for fixing the bug, and it is reasonable to return from readdir() when filldir() fails. Reported-by: Dave Jones <davej@redhat.com> Tested-by: Sasha Levin <levinsasha928@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * sysfs: fix race between readdir and lseekMing Lei2013-03-201-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While readdir() is running, lseek() may set filp->f_pos as zero, then may leave filp->private_data pointing to one sysfs_dirent object without holding its reference counter, so the sysfs_dirent object may be used after free in next readdir(). This patch holds inode->i_mutex to avoid the problem since the lock is always held in readdir path. Reported-by: Dave Jones <davej@redhat.com> Tested-by: Sasha Levin <levinsasha928@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | sysfs: use atomic_inc_unless_negative in sysfs_get_activeMaarten Lankhorst2013-03-251-15/+2
|/ | | | | | | | | | | It seems that sysfs has an interesting way of doing the same thing. This removes the cpu_relax unfortunately, but if it's really needed, it would be better to add this to include/linux/atomic.h to benefit all atomic ops users. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sysfs: sysfs_pathname/sysfs_add_one: Use strlcat() instead of strcat()Geert Uytterhoeven2012-10-241-8/+8
| | | | | | | | | | | | | | | The warning check for duplicate sysfs entries can cause a buffer overflow when printing the warning, as strcat() doesn't check buffer sizes. Use strlcat() instead. Since strlcat() doesn't return a pointer to the passed buffer, unlike strcat(), I had to convert the nested concatenation in sysfs_add_one() to an admittedly more obscure comma operator construct, to avoid emitting code for the concatenation if CONFIG_BUG is disabled. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge tag 'driver-core-3.6-rc1' of ↵Linus Torvalds2012-07-261-0/+10
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core changes from Greg Kroah-Hartman: "Here's the big driver core pull request for 3.6-rc1. Unlike 3.5, this kernel should be a lot tamer, with the printk changes now settled down. All we have here is some extcon driver updates, w1 driver updates, a few printk cleanups that weren't needed for 3.5, but are good to have now, and some other minor fixes/changes in the driver core. All of these have been in the linux-next releases for a while now. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>" * tag 'driver-core-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (38 commits) printk: Export struct log size and member offsets through vmcoreinfo Drivers: hv: Change the hex constant to a decimal constant driver core: don't trigger uevent after failure extcon: MAX77693: Add extcon-max77693 driver to support Maxim MAX77693 MUIC device sysfs: fail dentry revalidation after namespace change fix sysfs: fail dentry revalidation after namespace change extcon: spelling of detach in function doc extcon: arizona: Stop microphone detection if we give up on it extcon: arizona: Update cable reporting calls and split headset PM / Runtime: Do not increment device usage counts before probing kmsg - do not flush partial lines when the console is busy kmsg - export "continuation record" flag to /dev/kmsg kmsg - avoid warning for CONFIG_PRINTK=n compilations kmsg - properly print over-long continuation lines driver-core: Use kobj_to_dev instead of re-implementing it driver-core: Move kobj_to_dev from genhd.h to device.h driver core: Move deferred devices to the end of dpm_list before probing driver core: move uevent call to driver_register driver core: fix shutdown races with probe/remove(v3) Extcon: Arizona: Add driver for Wolfson Arizona class devices ...
| * sysfs: fail dentry revalidation after namespace change fixAndrew Morton2012-07-171-3/+5
| | | | | | | | | | | | | | | | | | | | | | don't assume that KOBJ_NS_TYPE_NONE==0. Also save a test-n-branch. Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * sysfs: fail dentry revalidation after namespace changeGlauber Costa2012-07-171-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we change the namespace tag of a sysfs entry, the associated dentry is still kept around. readdir() will work correctly and not display the old entries, but open() will still succeed, so will reads and writes. This will no longer happen if sysfs is remounted, hinting that this is a cache-related problem. I am using the following sequence to demonstrate that: shell1: ip link add type veth unshare -nm shell2: ip link set veth1 <pid_of_shell_1> cat /sys/devices/virtual/net/veth1/ifindex Before that patch, this will succeed (fail to fail). After it, it will correctly return an error. Differently from a normal rename, which we handle fine, changing the object namespace will keep it's path intact. So this check seems necessary as well. [ v2: get type from parent, as suggested by Eric Biederman ] Signed-off-by: Glauber Costa <glommer@parallels.com> CC: Tejun Heo <tj@kernel.org> Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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