linux/arch/m68k/mm
David Hildenbrand 70ffdb9393 mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler
Introduce faulthandler_disabled() and use it to check for irq context and
disabled pagefaults (via pagefault_disable()) in the pagefault handlers.

Please note that we keep the in_atomic() checks in place - to detect
whether in irq context (in which case preemption is always properly
disabled).

In contrast, preempt_disable() should never be used to disable pagefaults.
With !CONFIG_PREEMPT_COUNT, preempt_disable() doesn't modify the preempt
counter, and therefore the result of in_atomic() differs.
We validate that condition by using might_fault() checks when calling
might_sleep().

Therefore, add a comment to faulthandler_disabled(), describing why this
is needed.

faulthandler_disabled() and pagefault_disable() are defined in
linux/uaccess.h, so let's properly add that include to all relevant files.

This patch is based on a patch from Thomas Gleixner.

Reviewed-and-tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bigeasy@linutronix.de
Cc: borntraeger@de.ibm.com
Cc: daniel.vetter@intel.com
Cc: heiko.carstens@de.ibm.com
Cc: herbert@gondor.apana.org.au
Cc: hocko@suse.cz
Cc: hughd@google.com
Cc: mst@redhat.com
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: schwidefsky@de.ibm.com
Cc: yang.shi@windriver.com
Link: http://lkml.kernel.org/r/1431359540-32227-7-git-send-email-dahi@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-19 08:39:15 +02:00
..
cache.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k 2012-01-26 12:43:57 -08:00
fault.c mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler 2015-05-19 08:39:15 +02:00
hwtest.c m68k: Reformat arch/m68k/mm/hwtest.c 2014-10-03 10:50:56 +02:00
init.c m68k/mm: Eliminate memset after alloc_bootmem_pages 2014-11-10 09:56:44 +01:00
kmap.c m68k/mm: kmap spelling/grammar fixes 2013-12-30 21:01:11 +01:00
Makefile m68k: compile appropriate mm arch files for ColdFire MMU support 2011-12-30 10:20:39 +10:00
mcfmmu.c m68k: move to a single instance of free_initmem() 2012-11-14 08:50:56 +01:00
memory.c m68k: fix ColdFire clear cache operation 2012-07-17 15:49:34 +10:00
motorola.c m68k: Increase initial mapping to 8 or 16 MiB if possible 2014-05-28 10:11:54 +02:00
sun3kmap.c m68k: missing exports 2007-07-20 08:24:49 -07:00
sun3mmu.c m68k: move to a single instance of free_initmem() 2012-11-14 08:50:56 +01:00