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2015-03-27simple local unixlike: switch to ->iterate()Al Viro4-75/+59
ext2, ufs, minix, sysv Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-03-27introduce ->iterate(), ctx->pos, dir_emit()Al Viro7-18/+47
New method - ->iterate(file, ctx). That's the replacement for ->readdir(); it takes callback from ctx->actor, uses ctx->pos instead of file->f_pos and calls dir_emit(ctx, ...) instead of filldir(data, ...). It does *not* update file->f_pos (or look at it, for that matter); iterate_dir() does the update. Note that dir_emit() takes the offset from ctx->pos (and eventually filldir_t will lose that argument). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-03-27introduce iterate_dir() and dir_contextAl Viro10-20/+53
iterate_dir(): new helper, replacing vfs_readdir(). struct dir_context: contains the readdir callback (and will get more stuff in it), embedded into whatever data that callback wants to deal with; eventually, we'll be passing it to ->readdir() replacement instead of (data,filldir) pair. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-03-27sysfs: bail early from kernfs_file_mmap() to avoid spurious lockdep warningTejun Heo2-8/+22
This is v3.14 fix for the same issue that a8b14744429f ("sysfs: give different locking key to regular and bin files") addresses for v3.13. Due to the extensive kernfs reorganization in v3.14 branch, the same fix couldn't be ported as-is. The v3.13 fix was ignored while merging it into v3.14 branch. 027a485d12e0 ("sysfs: use a separate locking class for open files depending on mmap") assigned different lockdep key to sysfs_open_file->mutex depending on whether the file implements mmap or not in an attempt to avoid spurious lockdep warning caused by merging of regular and bin file paths. While this restored some of the original behavior of using different locks (at least lockdep is concerned) for the different clases of files. The restoration wasn't full because now the lockdep key assignment depends on whether the file has mmap or not instead of whether it's a regular file or not. This means that bin files which don't implement mmap will get assigned the same lockdep class as regular files. This is problematic because file_operations for bin files still implements the mmap file operation and checking whether the sysfs file actually implements mmap happens in the file operation after grabbing @sysfs_open_file->mutex. We still end up adding locking dependency from mmap locking to sysfs_open_file->mutex to the regular file mutex which triggers spurious circular locking warning. For v3.13, a8b14744429f ("sysfs: give different locking key to regular and bin files") fixed it by giving sysfs_open_file->mutex different lockdep keys depending on whether the file is regular or bin instead of whether mmap exists or not; however, due to the way sysfs is now layered behind kernfs, this approach is no longer viable. kernfs can tell whether a sysfs node has mmap implemented or not but can't tell whether a bin file from a regular one. This patch updates kernfs such that kernfs_file_mmap() checks SYSFS_FLAG_HAS_MMAP and bail before grabbing sysfs_open_file->mutex so that it doesn't add spurious locking dependency from mmap to sysfs_open_file->mutex and changes sysfs so that it specifies kernfs_ops->mmap iff the sysfs file implements mmap. Combined, this ensures that sysfs_open_file->mutex is grabbed under mmap path iff the sysfs file actually implements mmap. As sysfs_open_file->mutex is already given a different lockdep key if mmap is implemented, this removes the spurious locking dependency. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Dave Jones <davej@redhat.com> Link: http://lkml.kernel.org/g/20131203184324.GA11320@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: remove cross inclusions of internal headersTejun Heo2-3/+0
fs/kernfs/kernfs-internal.h needed to include fs/sysfs/sysfs.h because part of kernfs core implementation was living in sysfs. fs/sysfs/sysfs.h needed to include fs/kernfs/kernfs-internal.h because include/linux/kernfs.h didn't expose enough interface. The separation is complete and neither is true anymore. Remove the cross inclusion and make sysfs a proper user of kernfs. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: implement kernfs_ns_enabled()Tejun Heo4-7/+21
fs/sysfs/symlink.c::sysfs_delete_link() tests @sd->s_flags for SYSFS_FLAG_NS. Let's add kernfs_ns_enabled() so that sysfs doesn't have to test sysfs_dirent flag directly. This makes things tidier for kernfs proper too. This is purely cosmetic. v2: To avoid possible NULL deref, use noop dummy implementation which always returns false when !CONFIG_SYSFS. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: make sysfs_dirent definition publicTejun Heo3-103/+115
sysfs_dirent includes some information which should be available to kernfs users - the type, flags, name and parent pointer. This patch moves sysfs_dirent definition from kernfs/kernfs-internal.h to include/linux/kernfs.h so that kernfs users can access them. The type part of flags is exported as enum kernfs_node_type, the flags kernfs_node_flag, sysfs_type() and kernfs_enable_ns() are moved to include/linux/kernfs.h and the former is updated to return the enum type. sysfs_dirent->s_parent and ->s_name are marked explicitly as public. This patch doesn't introduce any functional changes. v2: Flags exported too and kernfs_enable_ns() definition moved. v3: While moving kernfs_enable_ns() to include/linux/kernfs.h, v1 and v2 put the definition outside CONFIG_SYSFS replacing the dummy implementation with the actual implementation too. Unfortunately, this can lead to oops when !CONFIG_SYSFS because kernfs_enable_ns() may be called on a NULL @sd and now tries to dereference @sd instead of not doing anything. This issue was reported by Yuanhan Liu. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: move mount core code to fs/kernfs/mount.cTejun Heo4-170/+178
Move core mount code to fs/kernfs/mount.c. The respective declarations in fs/sysfs/sysfs.h are moved to fs/kernfs/kernfs-internal.h. This is pure relocation. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: prepare mount path for kernfsTejun Heo5-35/+106
We're in the process of separating out core sysfs functionality into kernfs which will deal with sysfs_dirents directly. This patch rearranges mount path so that the kernfs and sysfs parts are separate. * As sysfs_super_info won't be visible outside kernfs proper, kernfs_super_ns() is added to allow kernfs users to access a super_block's namespace tag. * Generic mount operation is separated out into kernfs_mount_ns(). sysfs_mount() now just performs sysfs-specific permission check, acquires namespace tag, and invokes kernfs_mount_ns(). * Generic superblock release is separated out into kernfs_kill_sb() which can be used directly as file_system_type->kill_sb(). As sysfs needs to put the namespace tag, sysfs_kill_sb() wraps kernfs_kill_sb() with ns tag put. * sysfs_dir_cachep init and sysfs_inode_init() are separated out into kernfs_init(). kernfs_init() uses only small amount of memory and trying to handle and propagate kernfs_init() failure doesn't make much sense. Use SLAB_PANIC for sysfs_dir_cachep and make sysfs_inode_init() panic on failure. After this change, kernfs_init() should be called before sysfs_init(), fs/namespace.c::mnt_init() modified accordingly. 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>
2015-03-27sysfs, kernfs: make super_blocks bind to different kernfs_rootsTejun Heo2-4/+12
kernfs is being updated to allow multiple sysfs_dirent hierarchies so that it can also be used by other users. Currently, sysfs super_blocks are always attached to one kernfs_root - sysfs_root - and distinguished only by their namespace tags. This patch adds sysfs_super_info->root and update sysfs_fill/test_super() so that super_blocks are identified by the combination of both the associated kernfs_root and namespace tag. This allows mounting different kernfs hierarchies. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: make inode number ida per kernfs_rootTejun Heo5-38/+23
kernfs is being updated to allow multiple sysfs_dirent hierarchies so that it can also be used by other users. Currently, inode number is allocated using a global ida, sysfs_ino_ida; however, inos for different hierarchies should be handled separately. This patch makes ino allocation per kernfs_root. sysfs_ino_ida is replaced by kernfs_root->ino_ida and sysfs_new_dirent() is updated to take @root and allocate ino from it. ida_simple_get/remove() are used instead of sysfs_ino_lock and sysfs_alloc/free_ino(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: implement kernfs_create/destroy_root()Tejun Heo4-20/+113
There currently is single kernfs hierarchy in the whole system which is used for sysfs. kernfs needs to support multiple hierarchies to allow other users. This patch introduces struct kernfs_root which serves as the root of each kernfs hierarchy and implements kernfs_create/destroy_root(). * Each kernfs_root is associated with a root sd (sysfs_dentry). The root is freed when the root sd is released and kernfs_destory_root() simply invokes kernfs_remove() on the root sd. sysfs_remove_one() is updated to handle release of the root sd. Note that ps_iattr update in sysfs_remove_one() is trivially updated for readability. * Root sd's are now dynamically allocated using sysfs_new_dirent(). Update sysfs_alloc_ino() so that it gives out ino from 1 so that the root sd still gets ino 1. * While kernfs currently only points to the root sd, it'll soon grow fields which are specific to each hierarchy. As determining a given sd's root will be necessary, sd->s_dir.root is added. This backlink fits better as a separate field in sd; however, sd->s_dir is inside union with space to spare, so use it to save space and provide kernfs_root() accessor to determine the root sd. * As hierarchies may be destroyed now, each mount needs to hold onto the hierarchy it's attached to. Update sysfs_fill_super() and sysfs_kill_sb() so that they get and put the kernfs_root respectively. * sysfs_root is replaced with kernfs_root which is dynamically created by invoking kernfs_create_root() from sysfs_init(). This patch doesn't introduce any visible behavior changes. v2: kernfs_create_root() forgot to set @sd->priv. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: introduce sysfs_root_sdTejun Heo4-9/+11
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>
2015-03-27sysfs, kernfs: no need to kern_mount() sysfs from sysfs_init()Tejun Heo1-16/+7
It has been very long since sysfs depended on vfs to keep track of internal states and whether sysfs is mounted or not doesn't make any difference to sysfs's internal operation. In addition to init and filesystem type registration, sysfs_init() invokes kern_mount() to create in-kernel mount of sysfs. This internal mounting doesn't server any purpose anymore. Remove it. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: make sysfs_super_info->ns constTejun Heo2-8/+8
Add const qualifier to sysfs_super_info->ns so that it's consistent with other namespace tag usages in sysfs. Because kobject doesn't use const qualifier for namespace tags, this ends up requiring an explicit cast to drop const qualifier in free_sysfs_super_info(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: drop unused params from sysfs_fill_super()Tejun Heo1-2/+2
sysfs_fill_super() takes three params - @sb, @data and @silent - but uses only @sb. Drop the latter two. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: move symlink core code to fs/kernfs/symlink.cTejun Heo4-138/+144
Move core symlink code to fs/kernfs/symlink.c. fs/sysfs/symlink.c now only contains 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. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: move file core code to fs/kernfs/file.cTejun Heo4-805/+813
Move core file code to fs/kernfs/file.c. fs/sysfs/file.c now contains sysfs kernfs_ops callbacks, sysfs wrappers around kernfs interfaces, and sysfs_schedule_callback(). The respective declarations in fs/sysfs/sysfs.h are moved to fs/kernfs/kernfs-internal.h. This is pure relocation. v2: Refreshed on top of the v2 of "sysfs, kernfs: prepare read path for kernfs". v3: Refreshed on top of the v3 of "sysfs, kernfs: prepare read path for kernfs". Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: move dir core code to fs/kernfs/dir.cTejun Heo4-1027/+1005
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>
2015-03-27sysfs, kernfs: move inode code to fs/kernfs/inode.cTejun Heo5-355/+341
There's nothing sysfs-specific in fs/sysfs/inode.c. Move everything in it to fs/kernfs/inode.c. The respective declarations in fs/sysfs/sysfs.h are moved to fs/kernfs/kernfs-internal.h. This is pure relocation. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: move internal decls to fs/kernfs/kernfs-internal.hTejun Heo2-96/+121
Move data structure, constant and basic accessor declarations from fs/sysfs/sysfs.h to fs/kernfs/kernfs-internal.h. The two files currently include each other. Once kernfs / sysfs separation is complete, the cross inclusions will be removed. Inclusion protectors are added to fs/sysfs/sysfs.h to allow cross-inclusion. This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: introduce kernfs[_find_and]_get() and kernfs_put()Tejun Heo9-148/+150
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>
2015-03-27sysfs, kernfs: revamp sysfs_dirent active_ref lockdep annotationTejun Heo4-52/+56
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>
2015-03-27sysfs, kernfs: reorganize SYSFS_* constantsTejun Heo1-6/+6
We want to add one more SYSFS_FLAG_* but we can't use the next higher bit, 0x10000, as the flag field is 16bits wide. The flags are currently arranged weirdly - 8 bits are set aside for the type flags when there are only three three used, the first flag starts at 0x1000 instead of 0x0100 and flag literals have 5 digits (20 bits) when only 4 digits can be used. Rearrange them so that type bits are only the lowest four, flags start at 0x0010 and similar flags are grouped. This patch doesn't cause any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: introduce kernfs_notify()Tejun Heo3-15/+30
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>
2015-03-27sysfs, kernfs: add kernfs_ops->seq_{start|next|stop}()Tejun Heo2-13/+35
kernfs_ops currently only supports single_open() behavior which is pretty restrictive. Add optional callbacks ->seq_{start|next|stop}() which, when implemented, are invoked for seq_file traversal. This allows full seq_file functionality for kernfs users. This currently doesn't have any user and doesn't change any behavior. v2: Refreshed on top of the updated "sysfs, kernfs: prepare read path for kernfs". Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: remove sysfs_add_one()Tejun Heo4-41/+6
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>
2015-03-27sysfs, kernfs: introduce kernfs_create_file[_ns]()Tejun Heo2-11/+60
Introduce kernfs interface to create a file which takes and returns sysfs_dirents. The actual file creation part is separated out from sysfs_add_file_mode_ns() into kernfs_create_file_ns(). The former now only decides the kernfs_ops to use and the file's size and invokes the latter. This patch doesn't introduce behavior changes. 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>
2015-03-27sysfs, kernfs: remove SYSFS_KOBJ_BIN_ATTRTejun Heo4-26/+14
After kernfs_ops and sysfs_dirent->s_attr.size addition, the distinction between SYSFS_KOBJ_BIN_ATTR and SYSFS_KOBJ_ATTR is only necessary while creating files to decide which kernfs_ops to use. Afterwards, they behave exactly the same. This patch removes SYSFS_KOBJ_BIN_ATTR along with sysfs_is_bin(). sysfs_add_file[_mode_ns]() are updated to take bool @is_bin instead of @type. This patch doesn't introduce any behavior changes. This completely isolates the distinction between the two sysfs file types in the sysfs layer proper. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: add sysfs_dirent->s_attr.sizeTejun Heo3-7/+8
sysfs sets the size of regular files unconditionally at PAGE_SIZE and takes the size of bin files from bin_attribute. The latter is a pretty bad interface which forces bin_attribute users to create a separate copy of bin_attribute for each instance of the file - e.g. pci resource files. Add sysfs_dirent->s_attr.size so that the size can be specified separately. This unifies inode init paths of ATTR and BIN_ATTR identical and allows for generic size handling for kernfs. Unfortunately, this grows the size of sysfs_dirent by sizeof(loff_t). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: introduce kernfs_opsTejun Heo3-34/+141
We're in the process of separating out core sysfs functionality into kernfs which will deal with sysfs_dirents directly. This patch introduces kernfs_ops which hosts methods kernfs users implement and updates fs/sysfs/file.c such that sysfs_kf_*() functions populate kernfs_ops and kernfs_file_*() functions call the matching entries from kernfs_ops. kernfs_ops contains the following groups of methods. * seq_show() - for kernfs files which use seq_file for reads. * read() - for direct read implementations. Used iff seq_show() is not implemented. * write() - for writes. * mmap() - for mmaps. Notes: * sysfs_elem_attr->ops is added so that kernfs_ops can be accessed from sysfs_dirent. kernfs_ops() helper is added to verify locking and access the field. * SYSFS_FLAG_HAS_(SEQ_SHOW|MMAP) added. sd->s_attr->ops is accessible only while holding active_ref and there are cases where we want to take different actions depending on which ops are implemented. These two flags cache whether the two ops are implemented for those. * kernfs_file_*() no longer test sysfs type but chooses different behaviors depending on which methods in kernfs_ops are implemented. The conversions are trivial except for the open path. As kernfs_file_open() now decides whether to allow read/write accesses depending on the kernfs_ops implemented, the presence of methods in kobjs and attribute_bin should be propagated to kernfs_ops. sysfs_add_file_mode_ns() is updated so that it propagates presence / absence of the callbacks through _empty, _ro, _wo, _rw kernfs_ops. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs: use a separate locking class for open files depending on mmapTejun Heo1-2/+20
The following two commits implemented mmap support in the regular file path and merged bin file support into the regular path. 73d9714627ad ("sysfs: copy bin mmap support from fs/sysfs/bin.c to fs/sysfs/file.c") 3124eb1679b2 ("sysfs: merge regular and bin file handling") After the merge, the following commands trigger a spurious lockdep warning. "test-mmap-read" simply mmaps the file and dumps the content. $ cat /sys/block/sda/trace/act_mask $ test-mmap-read /sys/devices/pci0000\:00/0000\:00\:03.0/resource0 4096 ====================================================== [ INFO: possible circular locking dependency detected ] 3.12.0-work+ #378 Not tainted ------------------------------------------------------- test-mmap-read/567 is trying to acquire lock: (&of->mutex){+.+.+.}, at: [<ffffffff8120a8df>] sysfs_bin_mmap+0x4f/0x120 but task is already holding lock: (&mm->mmap_sem){++++++}, at: [<ffffffff8114b399>] vm_mmap_pgoff+0x49/0xa0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&mm->mmap_sem){++++++}: ... -> #2 (sr_mutex){+.+.+.}: ... -> #1 (&bdev->bd_mutex){+.+.+.}: ... -> #0 (&of->mutex){+.+.+.}: ... other info that might help us debug this: Chain exists of: &of->mutex --> sr_mutex --> &mm->mmap_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem); lock(sr_mutex); lock(&mm->mmap_sem); lock(&of->mutex); *** DEADLOCK *** 1 lock held by test-mmap-read/567: #0: (&mm->mmap_sem){++++++}, at: [<ffffffff8114b399>] vm_mmap_pgoff+0x49/0xa0 stack backtrace: CPU: 3 PID: 567 Comm: test-mmap-read Not tainted 3.12.0-work+ #378 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 ffffffff81ed41a0 ffff880009441bc8 ffffffff81611ad2 ffffffff81eccb80 ffff880009441c08 ffffffff8160f215 ffff880009441c60 ffff880009c75208 0000000000000000 ffff880009c751e0 ffff880009c75208 ffff880009c74ac0 Call Trace: [<ffffffff81611ad2>] dump_stack+0x4e/0x7a [<ffffffff8160f215>] print_circular_bug+0x2b0/0x2bf [<ffffffff8109ca0a>] __lock_acquire+0x1a3a/0x1e60 [<ffffffff8109d6ba>] lock_acquire+0x9a/0x1d0 [<ffffffff81615547>] mutex_lock_nested+0x67/0x3f0 [<ffffffff8120a8df>] sysfs_bin_mmap+0x4f/0x120 [<ffffffff8115d363>] mmap_region+0x3b3/0x5b0 [<ffffffff8115d8ae>] do_mmap_pgoff+0x34e/0x3d0 [<ffffffff8114b3ba>] vm_mmap_pgoff+0x6a/0xa0 [<ffffffff8115be3e>] SyS_mmap_pgoff+0xbe/0x250 [<ffffffff81008282>] SyS_mmap+0x22/0x30 [<ffffffff8161a4d2>] system_call_fastpath+0x16/0x1b This happens because one file nests sr_mutex, which nests mm->mmap_sem under it, under of->mutex while mmap implementation naturally nests of->mutex under mm->mmap_sem. The warning is false positive as of->mutex is per open-file and the two paths belong to two different files. This warning didn't trigger before regular and bin file supports were merged because only bin file supported mmap and the other side of locking happened only on regular files which used equivalent but separate locking. It'd be best if we give separate locking classes per file but we can't easily do that. Let's differentiate on ->mmap() for now. Later we'll add explicit file operations struct and can add per-ops lockdep key there. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: move sysfs_open_file to include/linux/kernfs.hTejun Heo2-11/+18
sysfs_open_file will be used as the primary handle for kernfs methods. Move its definition from fs/sysfs/file.c to include/linux/kernfs.h and mark the public and private fields. This is pure relocation. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: prepare open, release, poll paths for kernfsTejun Heo3-21/+10
We're in the process of separating out core sysfs functionality into kernfs which will deal with sysfs_dirents directly. This patch prepares the rest - open, release and poll. There isn't much to do. Just renaming is enough. As sysfs_file_operations and sysfs_bin_operations are identical now, use the same file_operations for both - kernfs_file_operations. 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>
2015-03-27sysfs, kernfs: prepare mmap path for kernfsTejun Heo1-31/+39
We're in the process of separating out core sysfs functionality into kernfs which will deal with sysfs_dirents directly. This patch rearranges mmap path so that the kernfs and sysfs parts are separate. sysfs_kf_bin_mmap() which handles the interaction with bin_attribute mmap method is factored out of sysfs_bin_mmap(), which is renamed to kernfs_file_mmap(). All vma ops are renamed accordingly. sysfs_bin_mmap() is updated such that it can be used for both file types. This will eventually allow using the same file_operations for both file types, which is necessary to separate out kernfs. 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>
2015-03-27sysfs, kernfs: prepare write path for kernfsTejun Heo1-54/+50
We're in the process of separating out core sysfs functionality into kernfs which will deal with sysfs_dirents directly. This patch rearranges write path so that the kernfs and sysfs parts are separate. kernfs_file_write() handles all boilerplate work including buffer management and locking and invokes sysfs_kf_write() or sysfs_kf_bin_write() depending on the file type which deals with the interaction with kobj store or bin_attribute write method. While this patch changes the order of some operations, it shouldn't change any visible behavior. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: prepare read path for kernfsTejun Heo1-65/+126
We're in the process of separating out core sysfs functionality into kernfs which will deal with sysfs_dirents directly. This patch rearranges read path so that the kernfs and sysfs parts are separate. * Regular file read path is refactored such that kernfs_seq_start/next/stop/show() handle all the boilerplate work including locking and updating event count for poll, while sysfs_kf_seq_show() deals with interaction with kobj show method. * Bin file read path is refactored such that kernfs_file_direct_read() handles all the boilerplate work including buffer management and locking, while sysfs_kf_bin_read() deals with interaction with bin_attribute read method. kernfs_file_read() is added. It invokes either the seq_file or direct read path depending on the file type. This will eventually allow using the same file_operations for both file types, which is necessary to separate out kernfs. While this patch changes the order of some operations, it shouldn't change any visible behavior. v2: Dropped unnecessary zeroing of @count from sysfs_kf_seq_show(). Add comments explaining single_open() behavior. Both suggested by Pavel. v3: seq_stop() is called even after seq_start() failed. kernfs_seq_start() updated so that it doesn't unlock sysfs_open_file->mutex on failure so that kernfs_seq_stop() doesn't try to unlock an already unlocked mutex. Reported by Fengguang. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs, kernfs: introduce kernfs_create_dir[_ns]()Tejun Heo6-37/+54
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>
2015-03-27sysfs, kernfs: replace sysfs_dirent->s_dir.kobj and ->s_attr.[bin_]attr with ↵Tejun Heo5-25/+22
->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>
2015-03-27sysfs: separate out dup filename warning into a separate functionTejun Heo2-11/+20
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>
2015-03-27sysfs: remove unused sysfs_get_dentry() prototypeTejun Heo1-1/+0
sysfs_get_dentry() has been gone for years now. Remove the left-over prototype. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs: honor bin_attr.attr.ignore_lockdepTejun Heo1-1/+3
ignore_lockdep is currently honored only for regular files. There's no reason to ignore it for bin files. Update sysfs_ignore_lockdep() so that bin_attr.attr.ignore_lockdep works too. While this doesn't have any in-kernel user, this unifies the behaviors between regular and bin files and will help later changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs: merge sysfs_elem_bin_attr into sysfs_elem_attrTejun Heo3-12/+9
3124eb1679 ("sysfs: merge regular and bin file handling") folded bin file handling into regular file handling. Among other things, bin file now shares the same open path including sysfs_open_dirent association using sysfs_dirent->s_attr.open. This is buggy because ->s_bin_attr lives in the same union and doesn't have the field. This bug doesn't trigger because sysfs_elem_bin_attr doesn't have an active field at the conflicting position. It does have a field "buffers" but it isn't used anymore. This patch collapses sysfs_elem_bin_attr into sysfs_elem_attr so that the bin_attr is accessed through ->s_attr.bin_attr which lives with ->s_attr.attr in an anonymous union. The code paths already assume bin_attr contains attr as the first element, so this doesn't add any more assumptions while making it explicit that the two types are handled together. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-27sysfs: make sysfs_file_ops() follow ignore_lockdep flagTejun Heo3-23/+22
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>
2015-03-27sysfs, kernfs: introduce kernfs_setattr()Tejun Heo4-11/+32
Introduce kernfs setattr interface - kernfs_setattr(). sysfs_sd_setattr() is renamed to __kernfs_setattr() and kernfs_setattr() is a simple wrapper around it with sysfs_mutex locking. sysfs_chmod_file() is updated to get an explicit ref on kobj->sd and then invoke kernfs_setattr() so that it doesn't have to use internal interface. This patch doesn't introduce any behavior differences. 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>
2015-03-27sysfs, kernfs: introduce kernfs_rename[_ns]()Tejun Heo4-12/+23
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>
2015-03-27sysfs, kernfs: introduce kernfs_create_link()Tejun Heo2-30/+55
Separate out kernfs symlink interface - kernfs_create_link() - which takes and returns sysfs_dirents, from sysfs_do_create_link_sd(). sysfs_do_create_link_sd() now just determines the parent and target sysfs_dirents and invokes the new interface and handles dup warning. This patch doesn't introduce behavior changes. 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>
2015-03-27sysfs, kernfs: introduce kernfs_remove[_by_name[_ns]]()Tejun Heo6-26/+46
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>
2015-03-27sysfs: move sysfs_hash_and_remove() to fs/sysfs/dir.cTejun Heo3-31/+40
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>
2015-03-27sysfs: make sure read buffer is zeroedTejun Heo1-1/+2
13c589d5b0ac ("sysfs: use seq_file when reading regular files") switched sysfs from custom read implementation to seq_file to enable later transition to kernfs. After the change, the buffer passed to ->show() is acquired through seq_get_buf(); unfortunately, this introduces a subtle behavior change. Before the commit, the buffer passed to ->show() was always zero as it was allocated using get_zeroed_page(). Because seq_file doesn't clear buffers on allocation and neither does seq_get_buf(), after the commit, depending on the behavior of ->show(), we may end up exposing uninitialized data to userland thus possibly altering userland visible behavior and leaking information. Fix it by explicitly clearing the buffer. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Ron <ron@debian.org> Fixes: 13c589d5b0ac ("sysfs: use seq_file when reading regular files") Cc: stable <stable@vger.kernel.org> # 3.13+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>