linux-toradex.git/drivers/char/misc.c, branch v4.9.60

char: make misc_deregister a void function

2015-08-05T17:35:49+00:00

With well over 200+ users of this api, there are a mere 12 users that
actually checked the return value of this function.  And all of them
really didn't do anything with that information as the system or module
was shutting down no matter what.

So stop pretending like it matters, and just return void from
misc_deregister().  If something goes wrong in the call, you will get a
WARNING splat in the syslog so you know how to fix up your driver.
Other than that, there's nothing that can go wrong.

Cc: Alasdair Kergon 
Cc: Neil Brown 
Cc: Oleg Drokin 
Cc: Andreas Dilger 
Cc: "Michael S. Tsirkin" 
Cc: Wim Van Sebroeck 
Cc: Christine Caulfield 
Cc: David Teigland 
Cc: Mark Fasheh 
Acked-by: Joel Becker 
Acked-by: Alexandre Belloni 
Acked-by: Alessandro Zummo 
Acked-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

char: misc: fix error path

2015-07-27T17:30:47+00:00

Lets call remove_proc_entry() in the error path only if we have
successfully created "misc" in procfs.

Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman

char: misc: remove redundant ifdef

2015-07-27T17:30:47+00:00

The check for CONFIG_PROC_FS is not required as the check is being done
in proc_fs.h and incase CONFIG_PROC_FS is not defined then proc_create()
is defined as NULL.

Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman

char: misc: restore MISC_DYNAMIC_MINOR on device_create() failure

2015-05-31T21:38:21+00:00

On attempt to register a dynamic minor misc device its minor number is
updated to a virtual minor number prior to device_create() call,
however on error path misc->minor == MISC_DYNAMIC_MINOR is not
restored.

Following the rule of thumb that a function returning an error must
not change the state of the caller, assign MISC_DYNAMIC_MINOR back.

The problem is met in a sutuation, when subsys_initcall(misc_init) is
not yet called and misc_class is not created, but misc_register()
modifies statically defined ".minor = MISC_DYNAMIC_MINOR", therefore
implicitly changing the client's logic on next attempt (e.g. retrying
from deferred list) to register a misc device, whose minor number is
converted from dynamic to some unknown static one.

Signed-off-by: Vladimir Zapolskiy 
Signed-off-by: Greg Kroah-Hartman

drivers: char: misc.c: remove trailing whitespace

2015-05-24T19:11:55+00:00

Remove trailing whitespace from several lines in drivers/char/misc.c
This was done using scripts/cleanfile

Signed-off-by: Tal Shorer 
Signed-off-by: Greg Kroah-Hartman

misc: pass miscdevice through file's private_data

2015-04-03T14:15:30+00:00

Make the miscdevice accessible through the file's private_data.

Previously, this was done only when an open() file operation had been
registered. If no custom open() file operation was defined,
private_data was set to NULL.

This subtle quirk was confusing, to the point where kernel code
registered *empty* file open operations to have private_data point to
the misc device structure and avoid duplicating that logic.

And it could easily lead to bugs, where the addition or removal of a
custom open() file operation surprisingly changes the initial value of
a file's private_data structure.

To resolve this, we now place the miscdevice in the file's private_data
member unconditionally when open() is called.

Signed-off-by: Tom Van Braeckel 
Signed-off-by: Greg Kroah-Hartman

misc: Add attribute groups

2015-03-25T10:44:52+00:00

Add groups field to struct miscdevice for passing the attribute groups
at device creation.  In this way, the driver can avoid the manual call
of device_create_file() after the device registration, which is
basically a racy operation, in addition to the reduction of manual
device_remove_file() calls.

Signed-off-by: Takashi Iwai 
Signed-off-by: Greg Kroah-Hartman

char: misc: document behaviour of open()

2015-03-25T10:36:38+00:00

an open syscall now assignes file->private_data to a pointer to the
miscdevice structure. This reminds people not to duplicate code if
they want this and not to depend on it being NULL.

Signed-off-by: Martin Kepplinger 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-11-13T06:34:18+00:00

Pull vfs updates from Al Viro:
 "All kinds of stuff this time around; some more notable parts:

   - RCU'd vfsmounts handling
   - new primitives for coredump handling
   - files_lock is gone
   - Bruce's delegations handling series
   - exportfs fixes

  plus misc stuff all over the place"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (101 commits)
  ecryptfs: ->f_op is never NULL
  locks: break delegations on any attribute modification
  locks: break delegations on link
  locks: break delegations on rename
  locks: helper functions for delegation breaking
  locks: break delegations on unlink
  namei: minor vfs_unlink cleanup
  locks: implement delegations
  locks: introduce new FL_DELEG lock flag
  vfs: take i_mutex on renamed file
  vfs: rename I_MUTEX_QUOTA now that it's not used for quotas
  vfs: don't use PARENT/CHILD lock classes for non-directories
  vfs: pull ext4's double-i_mutex-locking into common code
  exportfs: fix quadratic behavior in filehandle lookup
  exportfs: better variable name
  exportfs: move most of reconnect_path to helper function
  exportfs: eliminate unused "noprogress" counter
  exportfs: stop retrying once we race with rename/remove
  exportfs: clear DISCONNECTED on all parents sooner
  exportfs: more detailed comment for path_reconnect
  ...

consolidate the reassignments of ->f_op in ->open() instances

2013-10-25T03:34:53+00:00

Signed-off-by: Al Viro