Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h

Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h as all arch
files that #include the former also #include the latter.  See:

	grep -rl asm-generic/cmpxchg-local[.]h arch/ | sort > b
	grep -rl asm-generic/cmpxchg[.]h arch/ | sort > a
	comm a b

This simplifies the disintegration of asm-generic/system.h for arches that
don't have their own.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Create asm-generic/barrier.h

Create asm-generic/barrier.h and move the barrier definitions from
asm-generic/system.h to it.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h

Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h
to simplify disintegration of asm/system.h.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Split the switch_to() wrapper out of asm-generic/system.h

Split the switch_to() wrapper out of asm-generic/system.h into its own
asm-generic/system.h as part of the asm/system.h disintegration.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Split arch_align_stack() out from asm-generic/system.h

Split arch_align_stack() out from asm-generic/system.h into its own header of
asm-generic/exec.h as part of the asm/system.h disintegration.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Disintegrate asm/system.h for OpenRISC

Disintegrate asm/system.h for OpenRISC.  Not compiled.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
cc: linux@lists.openrisc.net
Move all declarations of free_initmem() to linux/mm.h

Move all declarations of free_initmem() to linux/mm.h so that there's only one
and it's used by everything.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-c6x-dev@linux-c6x.org
cc: microblaze-uclinux@itee.uq.edu.au
cc: linux-sh@vger.kernel.org
cc: sparclinux@vger.kernel.org
cc: x86@kernel.org
cc: linux-mm@kvack.org
Add #includes needed to permit the removal of asm/system.h

asm/system.h is a cause of circular dependency problems because it contains
commonly used primitive stuff like barrier definitions and uncommonly used
stuff like switch_to() that might require MMU definitions.

asm/system.h has been disintegrated by this point on all arches into the
following common segments:

 (1) asm/barrier.h

     Moved memory barrier definitions here.

 (2) asm/cmpxchg.h

     Moved xchg() and cmpxchg() here.  #included in asm/atomic.h.

 (3) asm/bug.h

     Moved die() and similar here.

 (4) asm/exec.h

     Moved arch_align_stack() here.

 (5) asm/elf.h

     Moved AT_VECTOR_SIZE_ARCH here.

 (6) asm/switch_to.h

     Moved switch_to() here.

Signed-off-by: David Howells <dhowells@redhat.com>
Remove all #inclusions of asm/system.h

Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
Delete all instances of asm/system.h

Delete all instances of asm/system.h as they should be redundant by this
point.

Signed-off-by: David Howells <dhowells@redhat.com>
dm exception store: fix init error path

Call the correct exit function on failure in dm_exception_store_init.

Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm crypt: fix mempool deadlock

This patch fixes a possible deadlock in dm-crypt's mempool use.

Currently, dm-crypt reserves a mempool of MIN_BIO_PAGES reserved pages.
It allocates first MIN_BIO_PAGES with non-failing allocation (the allocation
cannot fail and waits until the mempool is refilled). Further pages are
allocated with different gfp flags that allow failing.

Because allocations may be done in parallel, this code can deadlock. Example:
There are two processes, each tries to allocate MIN_BIO_PAGES and the processes
run simultaneously.
It may end up in a situation where each process allocates (MIN_BIO_PAGES / 2)
pages. The mempool is exhausted. Each process waits for more pages to be freed
to the mempool, which never happens.

To avoid this deadlock scenario, this patch changes the code so that only
the first page is allocated with non-failing gfp mask. Allocation of further
pages may fail.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm crypt: add missing error handling

Always set io->error to -EIO when an error is detected in dm-crypt.

There were cases where an error code would be set only if we finish
processing the last sector. If there were other encryption operations in
flight, the error would be ignored and bio would be returned with
success as if no error happened.

This bug is present in kcryptd_crypt_write_convert, kcryptd_crypt_read_convert
and kcryptd_async_done.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@kernel.org
Reviewed-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm thin: fix stacked bi_next usage

Avoid using the bi_next field for the holder of a cell when deferring
bios because a stacked device below might change it.  Store the
holder in a new field in struct cell instead.

When a cell is created, the bio that triggered creation (the holder) was
added to the same bio list as subsequent bios.  In some cases we pass
this holder bio directly to devices underneath.  If those devices use
the bi_next field there will be trouble...

This also simplifies some code that had to work out which bio was the
holder.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm persistent data: fix btree rebalancing after remove

When we remove an entry from a node we sometimes rebalance with it's
two neighbours.  This wasn't being done correctly; in some cases
entries have to move all the way from the right neighbour to the left
neighbour, or vice versa.  This patch pretty much re-writes the
balancing code to fix it.

This code is barely used currently; only when you delete a thin
device, and then only if you have hundreds of them in the same pool.
Once we have discard support, which removes mappings, this will be used
much more heavily.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm: document sysfs entries

Describe attributes provided by device-mapper in /sys/block.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm: add persistent data to MAINTAINERS

Update device-mapper MAINTAINERS entry to mention quilt working tree location
and persistent-data subdirectory.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm uevent: no longer experimental

Drop EXPERIMENTAL tag from dm-uevent.

It's not changed for a while and some userspace tools are relying upon it.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm raid: no longer experimental

The dm raid module (using md) is becoming the preferred way of creating long-lived
mirrors through userspace LVM so remove the EXPERIMENTAL tag.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
dm thin: correct comments

Remove documentation for unimplemented 'trim' message.

I'd planned a 'trim' target message for shrinking thin devices, but
this is better handled via the discard ioctl.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>