dm thin: irqsave must always be used with the pool->lock spinlock

Commit c140e1c4e23 ("dm thin: use per thin device deferred bio lists")
incorrectly stopped disabling irqs when taking the pool's spinlock.

Irqs must be disabled when taking the pool's spinlock otherwise a thread
could spin_lock(), then get interrupted to service thin_endio() in
interrupt context, which would then deadlock in spin_lock_irqsave().

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
dm thin: fix rcu_read_lock being held in code that can sleep

Commit c140e1c4e23 ("dm thin: use per thin device deferred bio lists")
introduced the use of an rculist for all active thin devices.  The use
of rcu_read_lock() in process_deferred_bios() can result in a BUG if a
dm_bio_prison_cell must be allocated as a side-effect of bio_detain():

 BUG: sleeping function called from invalid context at mm/mempool.c:203
 in_atomic(): 1, irqs_disabled(): 0, pid: 6, name: kworker/u8:0
 3 locks held by kworker/u8:0/6:
   #0:  ("dm-" "thin"){.+.+..}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550
   #1:  ((&pool->worker)){+.+...}, at: [<ffffffff8106be42>] process_one_work+0x192/0x550
   #2:  (rcu_read_lock){.+.+..}, at: [<ffffffff816360b5>] do_worker+0x5/0x4d0

We can't process deferred bios with the rcu lock held, since
dm_bio_prison_cell allocation may block if the bio-prison's cell mempool
is exhausted.

To fix:

- Introduce a refcount and completion field to each thin_c

- Add thin_get/put methods for adjusting the refcount.  If the refcount
  hits zero then the completion is triggered.

- Initialise refcount to 1 when creating thin_c

- When iterating the active_thins list we thin_get() whilst the rcu
  lock is held.

- After the rcu lock is dropped we process the deferred bios for that
  thin.

- When destroying a thin_c we thin_put() and then wait for the
  completion -- to avoid a race between the worker thread iterating
  from that thin_c and destroying the thin_c.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
dm verity: fix biovecs hash calculation regression

Commit 003b5c5719f159f4f4bf97511c4702a0638313dd ("block: Convert drivers
to immutable biovecs") incorrectly converted biovec iteration in
dm-verity to always calculate the hash from a full biovec, but the
function only needs to calculate the hash from part of the biovec (up to
the calculated "todo" value).

Fix this issue by limiting hash input to only the requested data size.

This problem was identified using the cryptsetup regression test for
veritysetup (verity-compat-test).

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.14+
x86: LLVMLinux: Wrap -mno-80387 with cc-option

Wrap -mno-80387 gcc options with cc-option so they don't break
clang.

Signed-off-by: Behan Webster <behanw@converseincode.com>
Cc: torvalds@linux-foundation.org
Cc: dwmw2@infradead.org
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/1398145227-25053-1-git-send-email-behanw@converseincode.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
x86/vsmp: Fix irq routing

Correct IRQ routing in case a vSMP box is detected
but the  Interrupt Routing Comply (IRC) value is set to
"comply", which leads to incorrect IRQ routing.

Before the patch:

When a vSMP box was detected and IRC was set to "comply",
users (and the kernel) couldn't effectively set the
destination of the IRQs. This is because the hook inside
vsmp_64.c always setup all CPUs as the IRQ destination using
cpumask_setall() as the return value for IRQ allocation mask.
Later, this "overrided" mask caused the kernel to set the IRQ
destination to the lowest online CPU in the mask (CPU0 usually).

After the patch:

When the IRC is set to "comply", users (and the kernel) can control
the destination of the IRQs as we will not be changing the
default "apic->vector_allocation_domain".

Signed-off-by: Oren Twaig <oren@scalemp.com>
Acked-by: Shai Fultheim <shai@scalemp.com>
Link: http://lkml.kernel.org/r/1398669697-2123-1-git-send-email-oren@scalemp.com
[ Minor readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
dm thin: use INIT_WORK_ONSTACK in noflush_work to avoid ODEBUG warning

Use INIT_WORK_ONSTACK to silence "ODEBUG: object is on stack, but not
annotated".

Reported-by: Zdeněk Kabeláč <zkabelac@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
dm cache: fix writethrough mode quiescing in cache_map

Commit 2ee57d58735 ("dm cache: add passthrough mode") inadvertently
removed the deferred set reference that was taken in cache_map()'s
writethrough mode support.  Restore taking this reference.

This issue was found with code inspection.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Cc: stable@vger.kernel.org # 3.13+
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Peter Anvin:
 "Two very small changes: one fix for the vSMP Foundation platform, and
  one to help LLVM not choke on options it doesn't understand (although
  it probably should)"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/vsmp: Fix irq routing
  x86: LLVMLinux: Wrap -mno-80387 with cc-option
Merge tag 'dm-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "A few dm-thinp fixes for changes merged in 3.15-rc1.

  A dm-verity fix for an immutable biovec regression that affects 3.14+.

  A dm-cache fix to properly quiesce when using writethrough mode (3.14+)"

* tag 'dm-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache: fix writethrough mode quiescing in cache_map
  dm thin: use INIT_WORK_ONSTACK in noflush_work to avoid ODEBUG warning
  dm verity: fix biovecs hash calculation regression
  dm thin: fix rcu_read_lock being held in code that can sleep
  dm thin: irqsave must always be used with the pool->lock spinlock