linux-toradex.git/drivers/char/raw.c, branch v3.10.78

raw: test against runtime value of max_raw_minors

2014-02-22T20:41:27+00:00

commit 5bbb2ae3d6f896f8d2082d1eceb6131c2420b7cf upstream.

bind_get() checks the device number it is called with. It uses
MAX_RAW_MINORS for the upper bound. But MAX_RAW_MINORS is set at compile
time while the actual number of raw devices can be set at runtime. This
means the test can either be too strict or too lenient. And if the test
ends up being too lenient bind_get() might try to access memory beyond
what was allocated for "raw_devices".

So check against the runtime value (max_raw_minors) in this function.

Signed-off-by: Paul Bolle 
Acked-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

new helper: file_inode(file)

2013-02-23T04:31:31+00:00

Signed-off-by: Al Viro

blockdev: remove bd_block_size_semaphore again

2012-11-29T18:52:19+00:00

This reverts the block-device direct access code to the previous
unlocked code, now that fs/buffer.c no longer needs external locking.

With this, fs/block_dev.c is back to the original version, apart from a
whitespace cleanup that I didn't want to revert.

Signed-off-by: Linus Torvalds

Fix a crash when block device is read and block size is changed at the same time

2012-09-26T05:46:40+00:00

The kernel may crash when block size is changed and I/O is issued
simultaneously.

Because some subsystems (udev or lvm) may read any block device anytime,
the bug actually puts any code that changes a block device size in
jeopardy.

The crash can be reproduced if you place "msleep(1000)" to
blkdev_get_blocks just before "bh->b_size = max_blocks <<
inode->i_blkbits;".
Then, run "dd if=/dev/ram0 of=/dev/null bs=4k count=1 iflag=direct"
While it is waiting in msleep, run "blockdev --setbsz 2048 /dev/ram0"
You get a BUG.

The direct and non-direct I/O is written with the assumption that block
size does not change. It doesn't seem practical to fix these crashes
one-by-one there may be many crash possibilities when block size changes
at a certain place and it is impossible to find them all and verify the
code.

This patch introduces a new rw-lock bd_block_size_semaphore. The lock is
taken for read during I/O. It is taken for write when changing block
size. Consequently, block size can't be changed while I/O is being
submitted.

For asynchronous I/O, the patch only prevents block size change while
the I/O is being submitted. The block size can change when the I/O is in
progress or when the I/O is being finished. This is acceptable because
there are no accesses to block size when asynchronous I/O is being
finished.

The patch prevents block size changing while the device is mapped with
mmap.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Jens Axboe

switch device_get_devnode() and ->devnode() to umode_t *

2012-01-04T03:54:55+00:00

both callers of device_get_devnode() are only interested in lower 16bits
and nobody tries to return anything wider than 16bit anyway.

Signed-off-by: Al Viro

char: Convert vmalloc/memset to vzalloc

2011-09-15T11:55:03+00:00

Signed-off-by: Joe Perches 
Signed-off-by: Jiri Kosina

RAW driver: Remove call to kobject_put().

2011-05-07T00:52:32+00:00

If cdev_add() fails, there is no justification for subsequently
calling kobject_put().

Signed-off-by: Robert P. J. Day 
Signed-off-by: Greg Kroah-Hartman

Allow setting of number of raw devices as a module parameter

2011-05-07T00:52:31+00:00

Allow setting of maximal number of raw devices as a module parameter. This
requires changing of static array into a vmalloced one (the array is going to
be too large for kmalloc).

Signed-off-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

block: make blkdev_get/put() handle exclusive access

2010-11-13T10:55:17+00:00

Over time, block layer has accumulated a set of APIs dealing with bdev
open, close, claim and release.

* blkdev_get/put() are the primary open and close functions.

* bd_claim/release() deal with exclusive open.

* open/close_bdev_exclusive() are combination of open and claim and
  the other way around, respectively.

* bd_link/unlink_disk_holder() to create and remove holder/slave
  symlinks.

* open_by_devnum() wraps bdget() + blkdev_get().

The interface is a bit confusing and the decoupling of open and claim
makes it impossible to properly guarantee exclusive access as
in-kernel open + claim sequence can disturb the existing exclusive
open even before the block layer knows the current open if for another
exclusive access.  Reorganize the interface such that,

* blkdev_get() is extended to include exclusive access management.
  @holder argument is added and, if is @FMODE_EXCL specified, it will
  gain exclusive access atomically w.r.t. other exclusive accesses.

* blkdev_put() is similarly extended.  It now takes @mode argument and
  if @FMODE_EXCL is set, it releases an exclusive access.  Also, when
  the last exclusive claim is released, the holder/slave symlinks are
  removed automatically.

* bd_claim/release() and close_bdev_exclusive() are no longer
  necessary and either made static or removed.

* bd_link_disk_holder() remains the same but bd_unlink_disk_holder()
  is no longer necessary and removed.

* open_bdev_exclusive() becomes a simple wrapper around lookup_bdev()
  and blkdev_get().  It also has an unexpected extra bdev_read_only()
  test which probably should be moved into blkdev_get().

* open_by_devnum() is modified to take @holder argument and pass it to
  blkdev_get().

Most of bdev open/close operations are unified into blkdev_get/put()
and most exclusive accesses are tested atomically at the open time (as
it should).  This cleans up code and removes some, both valid and
invalid, but unnecessary all the same, corner cases.

open_bdev_exclusive() and open_by_devnum() can use further cleanup -
rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop
special features.  Well, let's leave them for another day.

Most conversions are straight-forward.  drbd conversion is a bit more
involved as there was some reordering, but the logic should stay the
same.

Signed-off-by: Tejun Heo 
Acked-by: Neil Brown 
Acked-by: Ryusuke Konishi 
Acked-by: Mike Snitzer 
Acked-by: Philipp Reisner 
Cc: Peter Osterlund 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Jan Kara 
Cc: Andrew Morton 
Cc: Andreas Dilger 
Cc: "Theodore Ts'o" 
Cc: Mark Fasheh 
Cc: Joel Becker 
Cc: Alex Elder 
Cc: Christoph Hellwig 
Cc: dm-devel@redhat.com
Cc: drbd-dev@lists.linbit.com
Cc: Leo Chen 
Cc: Scott Branden 
Cc: Chris Mason 
Cc: Steven Whitehouse 
Cc: Dave Kleikamp 
Cc: Joern Engel 
Cc: reiserfs-devel@vger.kernel.org
Cc: Alexander Viro

Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl

2010-10-22T17:52:56+00:00

* 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
  vfs: make no_llseek the default
  vfs: don't use BKL in default_llseek
  llseek: automatically add .llseek fop
  libfs: use generic_file_llseek for simple_attr
  mac80211: disallow seeks in minstrel debug code
  lirc: make chardev nonseekable
  viotape: use noop_llseek
  raw: use explicit llseek file operations
  ibmasmfs: use generic_file_llseek
  spufs: use llseek in all file operations
  arm/omap: use generic_file_llseek in iommu_debug
  lkdtm: use generic_file_llseek in debugfs
  net/wireless: use generic_file_llseek in debugfs
  drm: use noop_llseek