Add missing module.h include to fix this:

  CC      arch/s390/kernel/stacktrace.o
arch/s390/kernel/stacktrace.c:84: warning: data definition has no type or storage class
arch/s390/kernel/stacktrace.c:84: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/s390/kernel/stacktrace.c:84: warning: parameter names (without types) in function declaration
arch/s390/kernel/stacktrace.c:97: warning: data definition has no type or storage class
arch/s390/kernel/stacktrace.c:97: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
arch/s390/kernel/stacktrace.c:97: warning: parameter names (without types) in function declaration
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>

Andrew Morton reported this against linux-next:

ERROR: ".save_stack_trace" [tests/backtracetest.ko] undefined!
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Cc: Holger Wolf <wolf@linux.vnet.ibm.com>
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

sparse gives us a few of these:
stacktrace.c:69:38: warning: incorrect type in argument 2
                    (different signedness)
stacktrace.c:69:38:    expected unsigned int *skip

Just get rid of the 'skip' argument since it is contained in the
struct stack_trace that gets passed anyway.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Simplify the stacktrace code:

 - remove the unused task argument to save_stack_trace, it's always
   current
 - remove the all_contexts flag, it's alwasy 0
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andi Kleen <ak@suse.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The latest kernel 2.6.19-rc1 triggers a bug in the s390 specific stack
trace code when compiled with gcc 3.4.
This patch fixes the latest lock dependency validator code (2.6.19-rc1)
on s390 gcc 3.4. The variable sp was fixed to r15 (which is the stack
pointer in the s390 abi) and assigned new values to r15. Therefore,
gcc 3.4 assigns a new value to r15 and does not restore it on exit (r15
is supposed to be call save) - the kernel stack is broken. Avoid trouble
by not assigning any new value to sp (r15).
Signed-off-by: NChristian Borntraeger <cborntra@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

- Remove unused all_contexts parameter
No caller used it
- Move skip argument into the structure (needed for
followon patches)

Cc: mingo@elte.hu
Signed-off-by: NAndi Kleen <ak@suse.de>

stacktrace interface for s390 as needed by lock validator.

[clg@fr.ibm.com: build fix]
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: NCedric Le Goater <clg@fr.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>