linux-stable.git/drivers/char/mem.c, branch linux-4.8.y

shmem: get_unmapped_area align huge page

2016-07-26T23:19:19+00:00

Provide a shmem_get_unmapped_area method in file_operations, called at
mmap time to decide the mapping address.  It could be conditional on
CONFIG_TRANSPARENT_HUGEPAGE, but save #ifdefs in other places by making
it unconditional.

shmem_get_unmapped_area() first calls the usual mm->get_unmapped_area
(which we treat as a black box, highly dependent on architecture and
config and executable layout).  Lots of conditions, and in most cases it
just goes with the address that chose; but when our huge stars are
rightly aligned, yet that did not provide a suitable address, go back to
ask for a larger arena, within which to align the mapping suitably.

There have to be some direct calls to shmem_get_unmapped_area(), not via
the file_operations: because of the way shmem_zero_setup() is called to
create a shmem object late in the mmap sequence, when MAP_SHARED is
requested with MAP_ANONYMOUS or /dev/zero.  Though this only matters
when /proc/sys/vm/shmem_huge has been set.

Link: http://lkml.kernel.org/r/1466021202-61880-29-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Hugh Dickins 
Signed-off-by: Kirill A. Shutemov 

Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86/mm/pat, /dev/mem: Remove superfluous error message

2016-07-08T09:52:58+00:00

Currently it's possible for broken (or malicious) userspace to flood a
kernel log indefinitely with messages a-la

	Program dmidecode tried to access /dev/mem between f0000->100000

because range_is_allowed() is case of CONFIG_STRICT_DEVMEM being turned on
dumps this information each and every time devmem_is_allowed() fails.

Reportedly userspace that is able to trigger contignuous flow of these
messages exists.

It would be possible to rate limit this message, but that'd have a
questionable value; the administrator wouldn't get information about all
the failing accessess, so then the information would be both superfluous
and incomplete at the same time :)

Returning EPERM (which is what is actually happening) is enough indication
for userspace what has happened; no need to log this particular error as
some sort of special condition.

Signed-off-by: Jiri Kosina 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Josh Poimboeuf 
Cc: Kees Cook 
Cc: Linus Torvalds 
Cc: Luis R. Rodriguez 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Toshi Kani 
Link: http://lkml.kernel.org/r/alpine.LNX.2.00.1607081137020.24757@cbobk.fhfr.pm
Signed-off-by: Ingo Molnar

drivers: char: mem: fix IS_ERROR_VALUE usage

2016-03-05T20:19:39+00:00

IS_ERR_VALUE macro should be used only with unsigned long type.
Specifically it works incorrectly with longer types.

The patch follows conclusion from discussion on LKML [1][2].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2120927
[2]: http://permalink.gmane.org/gmane.linux.kernel/2150581

Signed-off-by: Andrzej Hajda 
Acked-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

wrappers for ->i_mutex access

2016-01-22T23:04:28+00:00

parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested},
inode_foo(inode) being mutex_foo(&inode->i_mutex).

Please, use those for access to ->i_mutex; over the coming cycle
->i_mutex will become rwsem, with ->lookup() done with it held
only shared.

Signed-off-by: Al Viro

switch drivers/char/mem.c to ->read_iter/->write_iter

2015-04-12T02:29:40+00:00

Note that _these_ guys have ->read() and ->write() left in place - they are
eqiuvalent to what we'd get if we replaced those with NULL, but we are
talking about hot paths here.

Signed-off-by: Al Viro

make new_sync_{read,write}() static

2015-04-12T02:29:40+00:00

All places outside of core VFS that checked ->read and ->write for being NULL or
called the methods directly are gone now, so NULL {read,write} with non-NULL
{read,write}_iter will do the right thing in all cases.

Signed-off-by: Al Viro

fs: move struct kiocb to fs.h

2015-03-26T00:28:11+00:00

struct kiocb now is a generic I/O container, so move it to fs.h.
Also do a #include diet for aio.h while we're at it.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

Merge tag 'char-misc-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2015-02-15T18:48:44+00:00

Pull char / misc patches from Greg KH:
 "Here's the big char/misc driver update for 3.20-rc1.

  Lots of little things in here, all described in the changelog.
  Nothing major or unusual, except maybe the binder selinux stuff, which
  was all acked by the proper selinux people and they thought it best to
  come through this tree.

  All of this has been in linux-next with no reported issues for a while"

* tag 'char-misc-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (90 commits)
  coresight: fix function etm_writel_cp14() parameter order
  coresight-etm: remove check for unknown Kconfig macro
  coresight: fixing CPU hwid lookup in device tree
  coresight: remove the unnecessary function coresight_is_bit_set()
  coresight: fix the debug AMBA bus name
  coresight: remove the extra spaces
  coresight: fix the link between orphan connection and newly added device
  coresight: remove the unnecessary replicator property
  coresight: fix the replicator subtype value
  pdfdocs: Fix 'make pdfdocs' failure for 'uio-howto.tmpl'
  mcb: Fix error path of mcb_pci_probe
  virtio/console: verify device has config space
  ti-st: clean up data types (fix harmless memory corruption)
  mei: me: release hw from reset only during the reset flow
  mei: mask interrupt set bit on clean reset bit
  extcon: max77693: Constify struct regmap_config
  extcon: adc-jack: Release IIO channel on driver remove
  extcon: Remove duplicated include from extcon-class.c
  Drivers: hv: vmbus: hv_process_timer_expiration() can be static
  Drivers: hv: vmbus: serialize Offer and Rescind offer
  ...

fs: introduce f_op->mmap_capabilities for nommu mmap support

2015-01-20T21:02:58+00:00

Since "BDI: Provide backing device capability information [try #3]" the
backing_dev_info structure also provides flags for the kind of mmap
operation available in a nommu environment, which is entirely unrelated
to it's original purpose.

Introduce a new nommu-only file operation to provide this information to
the nommu mmap code instead.  Splitting this from the backing_dev_info
structure allows to remove lots of backing_dev_info instance that aren't
otherwise needed, and entirely gets rid of the concept of providing a
backing_dev_info for a character device.  It also removes the need for
the mtd_inodefs filesystem.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Tejun Heo 
Acked-by: Brian Norris 
Signed-off-by: Jens Axboe

drivers: char: mem: Fix Missing blank line issues

2015-01-12T13:04:11+00:00

Fixes "Missing a blank line after declarations" reported by
checkpatch.

This patch introduces no functional changes.

Signed-off-by: Rob Ward 
Signed-off-by: Greg Kroah-Hartman