linux.git/include/linux, branch v2.6.31

Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm

2009-09-05T20:51:07+00:00

* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
  dm snapshot: fix on disk chunk size validation
  dm exception store: split set_chunk_size
  dm snapshot: fix header corruption race on invalidation
  dm snapshot: refactor zero_disk_area to use chunk_io
  dm log: userspace add luid to distinguish between concurrent log instances
  dm raid1: do not allow log_failure variable to unset after being set
  dm log: remove incorrect field from userspace table output
  dm log: fix userspace status output
  dm stripe: expose correct io hints
  dm table: add more context to terse warning messages
  dm table: fix queue_limit checking device iterator
  dm snapshot: implement iterate devices
  dm multipath: fix oops when request based io fails when no paths

exec: do not sleep in TASK_TRACED under ->cred_guard_mutex

2009-09-05T18:30:42+00:00

Tom Horsley reports that his debugger hangs when it tries to read
/proc/pid_of_tracee/maps, this happens since

	"mm_for_maps: take ->cred_guard_mutex to fix the race with exec"
	04b836cbf19e885f8366bccb2e4b0474346c02d

commit in 2.6.31.

But the root of the problem lies in the fact that do_execve() path calls
tracehook_report_exec() which can stop if the tracer sets PT_TRACE_EXEC.

The tracee must not sleep in TASK_TRACED holding this mutex.  Even if we
remove ->cred_guard_mutex from mm_for_maps() and proc_pid_attr_write(),
another task doing PTRACE_ATTACH should not hang until it is killed or the
tracee resumes.

With this patch do_execve() does not use ->cred_guard_mutex directly and
we do not hold it throughout, instead:

	- introduce prepare_bprm_creds() helper, it locks the mutex
	  and calls prepare_exec_creds() to initialize bprm->cred.

	- install_exec_creds() drops the mutex after commit_creds(),
	  and thus before tracehook_report_exec()->ptrace_stop().

	  or, if exec fails,

	  free_bprm() drops this mutex when bprm->cred != NULL which
	  indicates install_exec_creds() was not called.

Reported-by: Tom Horsley 
Signed-off-by: Oleg Nesterov 
Acked-by: David Howells 
Cc: Roland McGrath 
Cc: James Morris 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

workqueues: introduce __cancel_delayed_work()

2009-09-05T18:30:42+00:00

cancel_delayed_work() has to use del_timer_sync() to guarantee the timer
function is not running after return.  But most users doesn't actually
need this, and del_timer_sync() has problems: it is not useable from
interrupt, and it depends on every lock which could be taken from irq.

Introduce __cancel_delayed_work() which calls del_timer() instead.

The immediate reason for this patch is
http://bugzilla.kernel.org/show_bug.cgi?id=13757
but hopefully this helper makes sense anyway.

As for 13757 bug, actually we need requeue_delayed_work(), but its
semantics are not yet clear.

Merge this patch early to resolves cross-tree interdependencies between
input and infiniband.

Signed-off-by: Oleg Nesterov 
Cc: Dmitry Torokhov 
Cc: Roland Dreier 
Cc: Stefan Richter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

dm log: userspace add luid to distinguish between concurrent log instances

2009-09-04T19:40:34+00:00

Device-mapper userspace logs (like the clustered log) are
identified by a universally unique identifier (UUID).  This
identifier is used to associate requests from the kernel to
a specific log in userspace.  The UUID must be unique everywhere,
since multiple machines may use this identifier when communicating
about a particular log, as is the case for cluster logs.

Sometimes, device-mapper/LVM may re-use a UUID.  This is the
case during pvmoves, when moving from one segment of an LV
to another, or when resizing a mirror, etc.  In these cases,
a new log is created with the same UUID and loaded in the
"inactive" slot.  When a device-mapper "resume" is issued,
the "live" table is deactivated and the new "inactive" table
becomes "live".  (The "inactive" table can also be removed
via a device-mapper 'clear' command.)

The above two issues were colliding.  More than one log was being
created with the same UUID, and there was no way to distinguish
between them.  So, sometimes the wrong log would be swapped
out during the exchange.

The solution is to create a locally unique identifier,
'luid', to go along with the UUID.  This new identifier is used
to determine exactly which log is being referenced by the kernel
when the log exchange is made.  The identifier is not
universally safe, but it does not need to be, since
create/destroy/suspend/resume operations are bound to a specific
machine; and these are the operations that make up the exchange.

Signed-off-by: Jonathan Brassow 
Signed-off-by: Alasdair G Kergon

dm stripe: expose correct io hints

2009-09-04T19:40:25+00:00

Set sensible I/O hints for striped DM devices in the topology
infrastructure added for 2.6.31 for userspace tools to
obtain via sysfs.

Add .io_hints to 'struct target_type' to allow the I/O hints portion
(io_min and io_opt) of the 'struct queue_limits' to be set by each
target and implement this for dm-stripe.

Signed-off-by: Mike Snitzer 
Signed-off-by: Alasdair G Kergon

lmb: Also remove __init from lmb_end_of_RAM() declaration in lmb.h

2009-09-01T03:30:14+00:00

My previous patch (commit 4f8ee2c9cc: "lmb: Remove __init from
lmb_end_of_DRAM()") removed __init in lmb.c but missed the fact that it
was also marked as such in the .h

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Linus Torvalds

flex_array: convert element_nr formals to unsigned

2009-08-27T03:06:52+00:00

It's problematic to allow signed element_nr's or total's to be passed as
part of the flex array API.

flex_array_alloc() allows total_nr_elements to be set to a negative
quantity, which is obviously erroneous.

flex_array_get() and flex_array_put() allows negative array indices in
dereferencing an array part, which could address memory mapped before
struct flex_array.

The fix is to convert all existing element_nr formals to be qualified as
unsigned.  Existing checks to compare it to total_nr_elements or the max
array size based on element_size need not be changed.

Signed-off-by: David Rientjes 
Cc: Dave Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

flex_array: declare parts member to have incomplete type

2009-08-27T03:06:52+00:00

The `parts' member of struct flex_array should evaluate to an incomplete
type so that sizeof() cannot be used and C99 does not require the
zero-length specification.

Signed-off-by: David Rientjes 
Acked-by: Dave Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: fix hugetlb bug due to user_shm_unlock call

2009-08-24T19:53:01+00:00

2.6.30's commit 8a0bdec194c21c8fdef840989d0d7b742bb5d4bc removed
user_shm_lock() calls in hugetlb_file_setup() but left the
user_shm_unlock call in shm_destroy().

In detail:
Assume that can_do_hugetlb_shm() returns true and hence user_shm_lock()
is not called in hugetlb_file_setup(). However, user_shm_unlock() is
called in any case in shm_destroy() and in the following
atomic_dec_and_lock(&up->__count) in free_uid() is executed and if
up->__count gets zero, also cleanup_user_struct() is scheduled.

Note that sched_destroy_user() is empty if CONFIG_USER_SCHED is not set.
However, the ref counter up->__count gets unexpectedly non-positive and
the corresponding structs are freed even though there are live
references to them, resulting in a kernel oops after a lots of
shmget(SHM_HUGETLB)/shmctl(IPC_RMID) cycles and CONFIG_USER_SCHED set.

Hugh changed Stefan's suggested patch: can_do_hugetlb_shm() at the
time of shm_destroy() may give a different answer from at the time
of hugetlb_file_setup().  And fixed newseg()'s no_id error path,
which has missed user_shm_unlock() ever since it came in 2.6.9.

Reported-by: Stefan Huber 
Signed-off-by: Hugh Dickins 
Tested-by: Stefan Huber 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds

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

2009-08-24T19:25:27+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: ucb1400_ts - enable interrupt unconditionally
  Input: ucb1400_ts - enable ADC Filter
  Input: wacom - don't use on-stack memory for report buffers
  Input: iforce - support new revision of ACT LABS Force RS
  Input: joydev - decouple axis and button map ioctls from input constants