linux.git/fs/sysfs/dir.c, branch v3.6

Merge tag 'driver-core-3.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2012-07-26T18:25:33+00:00

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 "

* 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 fix

2012-07-17T16:43:55+00:00

don't assume that KOBJ_NS_TYPE_NONE==0.  Also save a test-n-branch.

Cc: Eric W. Biederman 
Cc: Glauber Costa 
Cc: Tejun Heo 
Signed-off-by: Andrew Morton 
Acked-by: Serge E. Hallyn 
Signed-off-by: Greg Kroah-Hartman

sysfs: fail dentry revalidation after namespace change

2012-07-17T16:43:55+00:00

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 
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 
CC: Tejun Heo 
Reviewed-by: "Eric W. Biederman" 
Signed-off-by: Greg Kroah-Hartman

sysfs: just use d_materialise_unique()

2012-07-14T12:35:12+00:00

same as for nfs et.al.

Signed-off-by: Al Viro

sysfs: switch to ->s_d_op and ->d_release()

2012-07-14T12:35:06+00:00

a) ->d_iput() is wrong here - what we do to inode is completely usual, it's
dentry->d_fsdata that we want to drop.  Just use ->d_release().

b) switch to ->s_d_op - no need to play with d_set_d_op()

Signed-off-by: Al Viro

stop passing nameidata to ->lookup()

2012-07-14T12:34:32+00:00

Just the flags; only NFS cares even about that, but there are
legitimate uses for such argument.  And getting rid of that
completely would require splitting ->lookup() into a couple
of methods (at least), so let's leave that alone for now...

Signed-off-by: Al Viro

stop passing nameidata * to ->d_revalidate()

2012-07-14T12:34:14+00:00

Just the lookup flags.  Die, bastard, die...

Signed-off-by: Al Viro

sysfs: get rid of some lockdep false positives

2012-05-14T19:19:56+00:00

This patch (as1554) fixes a lockdep false-positive report.  The
problem arises because lockdep is unable to deal with the
tree-structured locks created by the device core and sysfs.

This particular problem involves a sysfs attribute method that
unregisters itself, not from the device it was called for, but from a
descendant device.  Lockdep doesn't understand the distinction and
reports a possible deadlock, even though the operation is safe.

This is the sort of thing that would normally be handled by using a
nested lock annotation; unfortunately it's not feasible to do that
here.  There's no sensible way to tell sysfs when attribute removal
occurs in the context of a parent attribute method.

As a workaround, the patch adds a new flag to struct attribute
telling sysfs not to inform lockdep when it acquires a readlock on a
sysfs_dirent instance for the attribute.  The readlock is still
acquired, but lockdep doesn't know about it and hence does not
complain about impossible deadlock scenarios.

Also added are macros for static initialization of attribute
structures with the ignore_lockdep flag set.  The three offending
attributes in the USB subsystem are converted to use the new macros.

Signed-off-by: Alan Stern 
Acked-by: Tejun Heo 
CC: Eric W. Biederman 
CC: Peter Zijlstra 
Signed-off-by: Greg Kroah-Hartman

sysfs: Removed dup_name entirely in sysfs_rename

2012-05-02T21:55:09+00:00

Since no one using "dup_name", removed it completely in sysfs_rename.

Signed-off-by: Sasikantha babu 
Signed-off-by: Greg Kroah-Hartman

sysfs: handle 'parent deleted before child added'

2012-04-10T21:48:51+00:00

In scsi at least two cases of the parent device being deleted before the
child is added have been observed.

1/ scsi is performing async scans and the device is removed prior to the
   async can thread running (can happen with an in-opportune / unlikely
   unplug during initial scan).

2/ libsas discovery event running after the parent port has been torn
   down (this is a bug in libsas).

Result in crash signatures like:
 BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
 IP: [] sysfs_create_dir+0x32/0xb6
 ...
 Process scsi_scan_8 (pid: 5417, threadinfo ffff88080bd16000, task ffff880801b8a0b0)
 Stack:
  00000000fffffffe ffff880813470628 ffff88080bd17cd0 ffff88080614b7e8
  ffff88080b45c108 00000000fffffffe ffff88080bd17d20 ffffffff8125e4a8
  ffff88080bd17cf0 ffffffff81075149 ffff88080bd17d30 ffff88080614b7e8
 Call Trace:
  [] kobject_add_internal+0x120/0x1e3
  [] ? trace_hardirqs_on+0xd/0xf
  [] kobject_add_varg+0x41/0x50
  [] kobject_add+0x64/0x66
  [] device_add+0x12d/0x63a

In this scenario the parent is still valid (because we have a
reference), but it has been device_del()'d which means its kobj->sd
pointer is NULL'd via:

 device_del()->kobject_del()->sysfs_remove_dir()

...and then sysfs_create_dir() (without this fix) goes ahead and
de-references parent_sd via sysfs_ns_type():

 return (sd->s_flags & SYSFS_NS_TYPE_MASK) >> SYSFS_NS_TYPE_SHIFT;

This scenario is being fixed in scsi/libsas, but if other subsystems
present the same ordering the system need not immediately crash.

Cc: Greg Kroah-Hartman 
Cc: James Bottomley 
Signed-off-by: Dan Williams 
Signed-off-by: Greg Kroah-Hartman