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* sysfs: Allow sysfs_notify_dirent to be called from interrupt context.Neil Brown2009-10-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | sysfs_notify_dirent is a simple atomic operation that can be used to alert user-space that new data can be read from a sysfs attribute. Unfortunately it cannot currently be called from non-process context because of its use of spin_lock which is sometimes taken with interrupts enabled. So change all lockers of sysfs_open_dirent_lock to disable interrupts, thus making sysfs_notify_dirent safe to be called from non-process context (as drivers/md does in md_safemode_timeout). sysfs_get_open_dirent is (documented as being) only called from process context, so it uses spin_lock_irq. Other places use spin_lock_irqsave. The usage for sysfs_notify_dirent in md_safemode_timeout was introduced in 2.6.28, so this patch is suitable for that and more recent kernels. Reported-by: Joel Andres Granados <jgranado@redhat.com> Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: file.c: use create_singlethread_workqueue()Andrew Morton2009-05-28
| | | | | | | | | | | We don't need a kernel thread per CPU for this application. Acked-by: Alex Chiang <achiang@hp.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: sysfs poll keep the poll rule of regular file.KOSAKI Motohiro2009-04-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, following test programs don't finished. % ruby -e ' Thread.new { sleep } File.read("/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies") ' strace expose the reason. ... open("/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies", O_RDONLY|O_LARGEFILE) = 3 ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbf9fa6b8) = -1 ENOTTY (Inappropriate ioctl for device) fstat64(3, {st_mode=S_IFREG|0444, st_size=4096, ...}) = 0 _llseek(3, 0, [0], SEEK_CUR) = 0 select(4, [3], NULL, NULL, NULL) = 1 (in [3]) read(3, "1400000 1300000 1200000 1100000 1"..., 4096) = 62 select(4, [3], NULL, NULL, NULL Because Ruby (the scripting language) VM assume select system-call against regular file don't block. it because SUSv3 says "Regular files shall always poll TRUE for reading and writing". see http://www.opengroup.org/onlinepubs/009695399/functions/poll.html it seems valid assumption. But sysfs_poll() don't keep this rule although sysfs file can read and write always. This patch restore proper poll behavior to sysfs. /sys/block/md*/md/sync_action polling application and another sysfs updating sensitive application still can use POLLERR and POLLPRI. Cc: Neil Brown <neilb@suse.de> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: don't use global workqueue in sysfs_schedule_callback()Alex Chiang2009-04-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A sysfs attribute using sysfs_schedule_callback() to commit suicide may end up calling device_unregister(), which will eventually call a driver's ->remove function. Drivers may call flush_scheduled_work() in their shutdown routines, in which case lockdep will complain with something like the following: ============================================= [ INFO: possible recursive locking detected ] 2.6.29-rc8-kk #1 --------------------------------------------- events/4/56 is trying to acquire lock: (events){--..}, at: [<ffffffff80257fc0>] flush_workqueue+0x0/0xa0 but task is already holding lock: (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230 other info that might help us debug this: 3 locks held by events/4/56: #0: (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230 #1: (&ss->work){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230 #2: (pci_remove_rescan_mutex){--..}, at: [<ffffffff803c10d1>] remove_callback+0x21/0x40 stack backtrace: Pid: 56, comm: events/4 Not tainted 2.6.29-rc8-kk #1 Call Trace: [<ffffffff8026dfcd>] validate_chain+0xb7d/0x1260 [<ffffffff8026eade>] __lock_acquire+0x42e/0xa40 [<ffffffff8026f148>] lock_acquire+0x58/0x80 [<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0 [<ffffffff8025800d>] flush_workqueue+0x4d/0xa0 [<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0 [<ffffffff80258070>] flush_scheduled_work+0x10/0x20 [<ffffffffa0144065>] e1000_remove+0x55/0xfe [e1000e] [<ffffffff8033ee30>] ? sysfs_schedule_callback_work+0x0/0x50 [<ffffffff803bfeb2>] pci_device_remove+0x32/0x70 [<ffffffff80441da9>] __device_release_driver+0x59/0x90 [<ffffffff80441edb>] device_release_driver+0x2b/0x40 [<ffffffff804419d6>] bus_remove_device+0xa6/0x120 [<ffffffff8043e46b>] device_del+0x12b/0x190 [<ffffffff8043e4f6>] device_unregister+0x26/0x70 [<ffffffff803ba969>] pci_stop_dev+0x49/0x60 [<ffffffff803baab0>] pci_remove_bus_device+0x40/0xc0 [<ffffffff803c10d9>] remove_callback+0x29/0x40 [<ffffffff8033ee4f>] sysfs_schedule_callback_work+0x1f/0x50 [<ffffffff8025769a>] run_workqueue+0x15a/0x230 [<ffffffff80257648>] ? run_workqueue+0x108/0x230 [<ffffffff8025846f>] worker_thread+0x9f/0x100 [<ffffffff8025bce0>] ? autoremove_wake_function+0x0/0x40 [<ffffffff802583d0>] ? worker_thread+0x0/0x100 [<ffffffff8025b89d>] kthread+0x4d/0x80 [<ffffffff8020d4ba>] child_rip+0xa/0x20 [<ffffffff8020cebc>] ? restore_args+0x0/0x30 [<ffffffff8025b850>] ? kthread+0x0/0x80 [<ffffffff8020d4b0>] ? child_rip+0x0/0x20 Although we know that the device_unregister path will never acquire a lock that a driver might try to acquire in its ->remove, in general we should never attempt to flush a workqueue from within the same workqueue, and lockdep rightly complains. So as long as sysfs attributes cannot commit suicide directly and we are stuck with this callback mechanism, put the sysfs callbacks on their own workqueue instead of the global one. This has the side benefit that if a suicidal sysfs attribute kicks off a long chain of ->remove callbacks, we no longer induce a long delay on the global queue. This also fixes a missing module_put in the error path introduced by sysfs-only-allow-one-scheduled-removal-callback-per-kobj.patch. We never destroy the workqueue, but I'm not sure that's a problem. Reported-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Alex Chiang <achiang@hp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: only allow one scheduled removal callback per kobjAlex Chiang2009-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The only way for a sysfs attribute to remove itself (without deadlock) is to use the sysfs_schedule_callback() interface. Vegard Nossum discovered that a poorly written sysfs ->store callback can repeatedly schedule remove callbacks on the same device over and over, e.g. $ while true ; do echo 1 > /sys/devices/.../remove ; done If the 'remove' attribute uses the sysfs_schedule_callback API and also does not protect itself from concurrent accesses, its callback handler will be called multiple times, and will eventually attempt to perform operations on a freed kobject, leading to many problems. Instead of requiring all callers of sysfs_schedule_callback to implement their own synchronization, provide the protection in the infrastructure. Now, sysfs_schedule_callback will only allow one scheduled callback per kobject. On subsequent calls with the same kobject, return -EAGAIN. This is a short term fix. The long term fix is to allow sysfs attributes to remove themselves directly, without any of this callback hokey pokey. [cornelia.huck@de.ibm.com: s390 ccwgroup bits] Reported-by: vegard.nossum@gmail.com Signed-off-by: Alex Chiang <achiang@hp.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: Make dir and name args to sysfs_notify() constTrent Piepho2008-10-16
| | | | | | | | | | | | | | Because they can be, and because code like this produces a warning if they're not: struct device_attribute dev_attr; sysfs_notify(&kobj, NULL, dev_attr.attr.name); Signed-off-by: Trent Piepho <tpiepho@freescale.com> CC: Neil Brown <neilb@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: Support sysfs_notify from atomic context with new sysfs_notify_direntNeil Brown2008-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | Support sysfs_notify from atomic context with new sysfs_notify_dirent sysfs_notify currently takes sysfs_mutex. This means that it cannot be called in atomic context. sysfs_mutex is sometimes held over a malloc (sysfs_rename_dir) so it can block on low memory. In md I want to be able to notify on a sysfs attribute from atomic context, and I don't want to block on low memory because I could be in the writeout path for freeing memory. So: - export the "sysfs_dirent" structure along with sysfs_get, sysfs_put and sysfs_get_dirent so I can get the sysfs_dirent that I want to notify on and hold it in an md structure. - split sysfs_notify_dirent out of sysfs_notify so the sysfs_dirent can be notified on with no blocking (just a spinlock). Signed-off-by: Neil Brown <neilb@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: crash debuggingAndrew Morton2008-10-16
| | | | | | | | | | | | Print the name of the last-accessed sysfs file when we oops, to help track down oopses which occur in sysfs store/read handlers. Because these oopses tend to not leave any trace of the offending code in the stack traces. Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Use WARN() in fs/sysfsArjan van de Ven2008-07-26
| | | | | | | | | | Use WARN() instead of a printk+WARN_ON() pair; this way the message becomes part of the warning section for better reporting/collection. Also, with this, one fo the if() sections collapses entirely into the WARN(). Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sysfs: don't call notify_changeMiklos Szeredi2008-07-22
| | | | | | | | | | | | | | sysfs_chmod_file() calls notify_change() to change the permission bits on a sysfs file. Replace with explicit call to sysfs_setattr() and fsnotify_change(). This is equivalent, except that security_inode_setattr() is not called. This function is called by drivers, so the security checks do not make any sense. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* fs: replace remaining __FUNCTION__ occurrencesHarvey Harrison2008-04-30
| | | | | | | | __FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [SCSI] sysfs: make group is_valid return a mode_tJames Bottomley2008-04-22
| | | | | | | | | | | | | We have a problem in scsi_transport_spi in that we need to customise not only the visibility of the attributes, but also their mode. Fix this by making the is_visible() callback return a mode, with 0 indicating is not visible. Also add a sysfs_update_group() API to allow us to change either the visibility or mode of the files at any time on the fly. Acked-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* sysfs: refill attribute buffer when reading from offset 0Dan Williams2008-04-19
| | | | | | | | | | | | | | | | | | | Requiring userspace to close and re-open sysfs attributes has been the policy since before 2.6.12. It allows userspace to get a consistent snapshot of kernel state and consume it with incremental reads and seeks. Now, if the file position is zero the kernel assumes userspace wants to see the new value. The application for this change is to allow a userspace RAID metadata handler to check the state of an array without causing any memory allocations. Thus not causing writeback to a raid array that might be blocked waiting for userspace to take action. Cc: Neil Brown <neilb@suse.de> Acked-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* SYSFS: Explicitly include required header file slab.h.Robert P. J. Day2008-04-19
| | | | | | | | | | | After an experimental deletion of the unnecessary inclusion of <linux/slab.h> from the header file <linux/percpu.h>, the following files under fs/sysfs were exposed as needing to explicitly include <linux/slab.h>. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* driver core: debug for bad dev_attr_show() return value.Andrew Morton2008-03-25
| | | | | | | | | | Try to find the culprit who caused http://bugzilla.kernel.org/show_bug.cgi?id=10150 Cc: <balajirrao@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6Linus Torvalds2008-01-25
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (200 commits) [SCSI] usbstorage: use last_sector_bug flag universally [SCSI] libsas: abstract STP task status into a function [SCSI] ultrastor: clean up inline asm warnings [SCSI] aic7xxx: fix firmware build [SCSI] aacraid: fib context lock for management ioctls [SCSI] ch: remove forward declarations [SCSI] ch: fix device minor number management bug [SCSI] ch: handle class_device_create failure properly [SCSI] NCR5380: fix section mismatch [SCSI] sg: fix /proc/scsi/sg/devices when no SCSI devices [SCSI] IB/iSER: add logical unit reset support [SCSI] don't use __GFP_DMA for sense buffers if not required [SCSI] use dynamically allocated sense buffer [SCSI] scsi.h: add macro for enclosure bit of inquiry data [SCSI] sd: add fix for devices with last sector access problems [SCSI] fix pcmcia compile problem [SCSI] aacraid: add Voodoo Lite class of cards. [SCSI] aacraid: add new driver features flags [SCSI] qla2xxx: Update version number to 8.02.00-k7. [SCSI] qla2xxx: Issue correct MBC_INITIALIZE_FIRMWARE command. ...
| * [SCSI] sysfs: fix the sysfs_add_file_to_group interfacesJames Bottomley2008-01-23
| | | | | | | | | | | | | | | | | | | | | | I can't see a reason why these shouldn't work on every group. However, they only seem to work on named groups. This patch allows the group functions to work on anonymous groups (those with NULL names). Acked-by: Tejun Heo <htejun@gmail.com> Acked-by: Kay Sievers <kay.sievers@vrfy.org> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* | Driver Core: kill subsys_attribute and default sysfs opsKay Sievers2008-01-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the no longer needed subsys_attributes, they are all converted to the more sensical kobj_attributes. There is no longer a magic fallback in sysfs attribute operations, all kobjects which create simple attributes need explicitely a ktype assigned, which tells the core what was intended here. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | kobject: remove struct kobj_type from struct ksetGreg Kroah-Hartman2008-01-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't need a "default" ktype for a kset. We should set this explicitly every time for each kset. This change is needed so that we can make ksets dynamic, and cleans up one of the odd, undocumented assumption that the kset/kobject/ktype model has. This patch is based on a lot of help from Kay Sievers. Nasty bug in the block code was found by Dave Young <hidave.darkstar@gmail.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | sysfs: remove SPIN_LOCK_UNLOCKEDJiri Slaby2008-01-24
|/ | | | | | | | | | SPIN_LOCK_UNLOCKED is deprecated, use DEFINE_SPINLOCK instead Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Tejun Heo <teheo@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: fix off-by-one error in fill_read_buffer()Miao Xie2007-11-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I found that there is a off-by-one problem in the following code. Version: 2.6.24-rc2 File: fs/sysfs/file.c:118-122 Function: fill_read_buffer -------------------------------------------------------------------- count = ops->show(kobj, attr_sd->s_attr.attr, buffer->page); sysfs_put_active_two(attr_sd); BUG_ON(count > (ssize_t)PAGE_SIZE); -------------------------------------------------------------------- Because according to the specification of the sysfs and the implement of the show methods, the show methods return the number of bytes which would be generated for the given input, excluding the trailing null.So if the return value of the show methods equals PAGE_SIZE - 1, the buffer is full in fact. And if the return value equals PAGE_SIZE, the resulting string was already truncated,or buffer overflow occurred. This patch fixes an off-by-one error in fill_read_buffer. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Tejun Heo <teheo@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: trivial: fix sysfs_create_file kerneldoc spelling mistakeChris Malley2007-10-19
| | | | | | | Spelling error in sysfs_create_file kerneldoc. Signed-off-by: Chris Malley <mail@chrismalley.co.uk> Signed-off-by: Adrian Bunk <bunk@kernel.org>
* sysfs: add copyrightsTejun Heo2007-10-12
| | | | | | | | | Sysfs has gone through considerable amount of reimplementation. Add copyrights. Any objections? :-) Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: move sysfs file poll implementation to sysfs_open_direntTejun Heo2007-10-12
| | | | | | | | | | | | | | | | | | | | | | | | | Sysfs file poll implementation is scattered over sysfs and kobject. Event numbering is done in sysfs_dirent but wait itself is done on kobject. This not only unecessarily bloats both kobject and sysfs_dirent but is also buggy - if a sysfs_dirent is removed while there still are pollers, the associaton betwen the kobject and sysfs_dirent breaks and kobject may be freed with the pollers still sleeping on it. This patch moves whole poll implementation into sysfs_open_dirent. Each time a sysfs_open_dirent is created, event number restarts from 1 and pollers sleep on sysfs_open_dirent. As event sequence number is meaningless without any open file and pollers should have open file and thus sysfs_open_dirent, this ephemeral event counting works and is a saner implementation. This patch fixes the dnagling sleepers bug and reduces the sizes of kobject and sysfs_dirent by one pointer. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: implement sysfs_open_direntTejun Heo2007-10-12
| | | | | | | | | | | | | | | Implement sysfs_open_dirent which represents an open file (attribute) sysfs_dirent. A file sysfs_dirent with one or more open files have one sysfs_dirent and all sysfs_buffers (one for each open instance) are linked to it. sysfs_open_dirent doesn't actually do anything yet but will be used to off-load things which are specific for open file sysfs_dirent from it. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: make s_elem an anonymous unionTejun Heo2007-10-12
| | | | | | | | | | Make s_elem an anonymous union. Prefixing with s_elem makes things needlessly longer without any advantage. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: kill unnecessary NULL pointer check in sysfs_release()Tejun Heo2007-10-12
| | | | | | | | | | | In sysfs_release(), sysfs_buffer pointed to by filp->private_data is guaranteed to exist. Kill the unnecessary NULL check. This also makes the code more consistent with the counterpart in fs/sysfs/bin.c. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: kill unnecessary sysfs_get() in open pathsTejun Heo2007-10-12
| | | | | | | | | | | | | There's no reason to get an extra reference to sysfs_dirent for an open file. Open file has a reference to the dentry which in turn has a reference to sysfs_dirent. This is fairly obvious as otherwise open itself won't be able to access the sysfs_dirent. Kill the extra sysfs_get() and matching sysfs_put(). Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: kill sysfs_update_file()Tejun Heo2007-10-12
| | | | | | | | | | | | | | sysfs_update_file() depends on inode->i_mtime but sysfs iondes are now reclaimable making the reported modification time unreliable. There's only one user (pci hotplug) of this notification mechanism and it reportedly isn't utilized from userland. Kill sysfs_update_file(). Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: fix sysfs_chmod_file() such that it updates sd->s_mode tooTejun Heo2007-10-12
| | | | | | | | | | | | sysfs_chmod_file() looked and updated only inode of the target file. Dentry and inode are reclaimable and the update mode data will go away when the inode is reclaimed. This patch makes sysfs_chmod_file() update sd->s_mode too such that the change is permanent. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: Introduce sysfs_rename_mutexEric W. Biederman2007-10-12
| | | | | | | | | | | | | | | | | | | | | Looking carefully at the rename code we have a subtle dependency that the structure of sysfs not change while we are performing a rename. If the parent directory of the object we are renaming changes while the rename is being performed nasty things could happen when we go to release our locks. So introduce a sysfs_rename_mutex to prevent this highly unlikely theoretical issue. In addition hold sysfs_rename_mutex over all calls to sysfs_get_dentry. Allowing sysfs_get_dentry to be simplified in the future. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: Fix typos in fs/sysfs/file.cRolf Eike Beer2007-10-12
| | | | | | | Signed-off-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: make sysfs_add_one() automatically check for duplicate entryTejun Heo2007-10-12
| | | | | | | | | | | | Make sysfs_add_one() check for duplicate entry and return -EEXIST if such entry exists. This simplifies node addition code a bit. This patch doesn't introduce any noticeable behavior change. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: make sysfs_add/remove_one() call link/unlink_sibling() implictlyTejun Heo2007-10-12
| | | | | | | | | | | | | | | | | When adding or removing a sysfs_dirent, the user used to be required to call link/unlink separately. It was for two reasons - code looked like that before sysfs_addrm_cxt conversion and to avoid looping through parent_sd->children list twice during removal. Performance optimization during removal just isn't worth it. Make sysfs_add/remove_one() call sysfs_link/unlink_sibing() implicitly. This makes code simpler albeit slightly less efficient. This change doesn't introduce any noticeable behavior change. Signed-off-by: Tejun Heo <htejun@gmail.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs/file.c - use mutex instead of semaphoreDave Young2007-10-12
| | | | | | | | Use mutex instead of semaphore in sysfs/file.c : sys_buffer. Signed-off-by: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: cosmetic clean up on node creation failure pathsTejun Heo2007-07-18
| | | | | | | | | | | | | | | | | | | | | | Node addition failure is detected by testing return value of sysfs_addfm_finish() which returns the number of added and removed nodes. As the function is called as the last step of addition right on top of error handling block, the if blocks looked like the following. if (sysfs_addrm_finish(&acxt)) success handling, usually return; /* fall through to error handling */ This is the opposite of usual convention in sysfs and makes the code difficult to understand. This patch inverts the test and makes those blocks look more like others. Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Gabriel C <nix.or.die@googlemail.com> Cc: Miles Lane <miles.lane@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: make directory dentries and inodes reclaimableTejun Heo2007-07-11
| | | | | | | | | | | | | | | | | | | | | This patch makes dentries and inodes for sysfs directories reclaimable. * sysfs_notify() is modified to walk sysfs_dirent tree instead of dentry tree. * sysfs_update_file() and sysfs_chmod_file() use sysfs_get_dentry() to grab the victim dentry. * sysfs_rename_dir() and sysfs_move_dir() grab all dentries using sysfs_get_dentry() on startup. * Dentries for all shadowed directories are pinned in memory to serve as lookup start point. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: restructure add/remove paths and fix inode updateTejun Heo2007-07-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original add/remove code had the following problems. * parent's timestamps are updated on dentry instantiation. this is incorrect with reclaimable files. * updating parent's timestamps isn't synchronized. * parent nlink update assumes the inode is accessible which won't be true once directory dentries are made reclaimable. This patch restructures add/remove paths to resolve the above problems. Add/removal are done in the following steps. 1. sysfs_addrm_start() : acquire locks including sysfs_mutex and other resources. 2-a. sysfs_add_one() : add new sd. linking the new sd into the children list is caller's responsibility. 2-b. sysfs_remove_one() : remove a sd. unlinking the sd from the children list is caller's responsibility. 3. sysfs_addrm_finish() : release all resources and clean up. Steps 2-a and/or 2-b can be repeated multiple times. Parent's inode is looked up during sysfs_addrm_start(). If available (always at the moment), it's pinned and nlink is updated as sd's are added and removed. Timestamps are updated during finish if any sd has been added or removed. If parent's inode is not available during start, sysfs_mutex ensures that parent inode is not created till add/remove is complete. All the complexity is contained inside the helper functions. Especially, dentry/inode handling is properly hidden from the rest of sysfs which now mostly operate on sysfs_dirents. As an added bonus, codes which use these helpers to add and remove sysfs_dirents are now more structured and simpler. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: use sysfs_mutex to protect the sysfs_dirent treeTejun Heo2007-07-11
| | | | | | | | | | | | | | As kobj sysfs dentries and inodes are gonna be made reclaimable, i_mutex can't be used to protect sysfs_dirent tree. Use sysfs_mutex globally instead. As the whole tree is protected with sysfs_mutex, there is no reason to keep sysfs_rename_sem. Drop it. While at it, add docbook comments to functions which require sysfs_mutex locking. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: make kobj point to sysfs_dirent instead of dentryTejun Heo2007-07-11
| | | | | | | | | | | | As kobj sysfs dentries and inodes are gonna be made reclaimable, dentry can't be used as naming token for sysfs file/directory, replace kobj->dentry with kobj->sd. The only external interface change is shadow directory handling. All other changes are contained in kobj and sysfs. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: implement sysfs_find_dirent() and sysfs_get_dirent()Tejun Heo2007-07-11
| | | | | | | | | | Implement sysfs_find_dirent() and sysfs_get_dirent(). sysfs_dirent_exist() is replaced by sysfs_find_dirent(). These will be used to make directory entries reclamiable. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: kill unnecessary attribute->ownerTejun Heo2007-07-11
| | | | | | | | | | | | | | | | | | | | | | | | | | sysfs is now completely out of driver/module lifetime game. After deletion, a sysfs node doesn't access anything outside sysfs proper, so there's no reason to hold onto the attribute owners. Note that often the wrong modules were accounted for as owners leading to accessing removed modules. This patch kills now unnecessary attribute->owner. Note that with this change, userland holding a sysfs node does not prevent the backing module from being unloaded. For more info regarding lifetime rule cleanup, please read the following message. http://article.gmane.org/gmane.linux.kernel/510293 (tweaked by Greg to not delete the field just yet, to make it easier to merge things properly.) Signed-off-by: Tejun Heo <htejun@gmail.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: kill attribute file orphaningTejun Heo2007-07-11
| | | | | | | | | | | Now that sysfs_dirent can be disconnected from kobject on deletion, there is no need to orphan each attribute files. All [bin_]attribute nodes are automatically orphaned when the parent node is deleted. Kill attribute file orphaning. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: implement sysfs_dirent active reference and immediate disconnectTejun Heo2007-07-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sysfs: implement sysfs_dirent active reference and immediate disconnect Opening a sysfs node references its associated kobject, so userland can arbitrarily prolong lifetime of a kobject which complicates lifetime rules in drivers. This patch implements active reference and makes the association between kobject and sysfs immediately breakable. Now each sysfs_dirent has two reference counts - s_count and s_active. s_count is a regular reference count which guarantees that the containing sysfs_dirent is accessible. As long as s_count reference is held, all sysfs internal fields in sysfs_dirent are accessible including s_parent and s_name. The newly added s_active is active reference count. This is acquired by invoking sysfs_get_active() and it's the caller's responsibility to ensure sysfs_dirent itself is accessible (should be holding s_count one way or the other). Dereferencing sysfs_dirent to access objects out of sysfs proper requires active reference. This includes access to the associated kobjects, attributes and ops. The active references can be drained and denied by calling sysfs_deactivate(). All active sysfs_dirents must be deactivated after deletion but before the default reference is dropped. This enables immediate disconnect of sysfs nodes. Once a sysfs_dirent is deleted, it won't access any entity external to sysfs proper. Because attr/bin_attr ops access both the node itself and its parent for kobject, they need to hold active references to both. sysfs_get/put_active_two() helpers are provided to help grabbing both references. Parent's is acquired first and released last. Unlike other operations, mmapped area lingers on after mmap() is finished and the module implement implementing it and kobj need to stay referenced till all the mapped pages are gone. This is accomplished by holding one set of active references to the bin_attr and its parent if there have been any mmap during lifetime of an openfile. The references are dropped when the openfile is released. This change makes sysfs lifetime rules independent from both kobject's and module's. It not only fixes several race conditions caused by sysfs not holding onto the proper module when referencing kobject, but also helps fixing and simplifying lifetime management in driver model and drivers by taking sysfs out of the equation. Please read the following message for more info. http://article.gmane.org/gmane.linux.kernel/510293 Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: make sysfs_dirent->s_element a unionTejun Heo2007-07-11
| | | | | | | | | | | | | | | | | | | | | Make sd->s_element a union of sysfs_elem_{dir|symlink|attr|bin_attr} and rename it to s_elem. This is to achieve... * some level of type checking : changing symlink to point to sysfs_dirent instead of kobject is much safer and less painful now. * easier / standardized dereferencing * allow sysfs_elem_* to contain more than one entry Where possible, pointer is obtained by directly deferencing from sd instead of going through other entities. This reduces dependencies to dentry, inode and kobject. to_attr() and to_bin_attr() are unused now and removed. This is in preparation of object reference simplification. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: add sysfs_dirent->s_nameTejun Heo2007-07-11
| | | | | | | | | | | | | | | | | Add s_name to sysfs_dirent. This is to further reduce dependency to the associated dentry. Name is copied for directories and symlinks but not for attributes. Where possible, name dereferences are converted to use sd->s_name. sysfs_symlink->link_name and sysfs_get_name() are unused now and removed. This change allows symlink to be implemented using sysfs_dirent tree proper, which is the last remaining dentry-dependent sysfs walk. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sysfs: consolidate sysfs_dirent creation functionsTejun Heo2007-07-11
| | | | | | | | | | | | | | | | | | | | | Currently there are four functions to create sysfs_dirent - __sysfs_new_dirent(), sysfs_new_dirent(), __sysfs_make_dirent() and sysfs_make_dirent(). Other than sysfs_make_dirent(), no function has two users if calls to implement other functions are excluded. This patch consolidates sysfs_dirent creation functions into the following two. * sysfs_new_dirent() : allocate and initialize * sysfs_attach_dirent() : attach to sysfs_dirent hierarchy and/or associate with dentry This simplifies interface and gives callers more flexibility. This is in preparation of object reference simplification. Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* use simple_read_from_buffer() in fs/Akinobu Mita2007-05-09
| | | | | | | | | | Cleanup using simple_read_from_buffer() in binfmt_misc, configfs, and sysfs. Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Joel Becker <joel.becker@oracle.com> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* remove "struct subsystem" as it is no longer neededGreg Kroah-Hartman2007-05-02
| | | | | | | | | | | We need to work on cleaning up the relationship between kobjects, ksets and ktypes. The removal of 'struct subsystem' is the first step of this, especially as it is not really needed at all. Thanks to Kay for fixing the bugs in this patch. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* device_schedule_callback() needs a module referenceAlan Stern2007-04-27
| | | | | | | | | | | | | | | This patch (as896b) fixes an oversight in the design of device_schedule_callback(). It is necessary to acquire a reference to the module owning the callback routine, to prevent the module from being unloaded before the callback can run. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Cc: Satyam Sharma <satyam.sharma@gmail.com> Cc: Neil Brown <neilb@suse.de> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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