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	xtensa: support highmem in aliasing cache flushing code	2014-08-14 11:59:23 +04:00
fault.c	mm/fault, arch: Use pagefault_disable() to check for disabled pagefaults in the handler	2015-05-19 08:39:15 +02:00
highmem.c	sched/preempt, mm/kmap: Explicitly disable/enable preemption in kmap_atomic_*	2015-05-19 08:39:14 +02:00
init.c	xtensa: nommu: clean up memory map dump	2014-10-21 13:28:58 +04:00
Makefile	xtensa: nommu: don't build most of the cache flushing code	2014-10-21 13:28:50 +04:00
misc.S	xtensa: implement clear_user_highpage and copy_user_highpage	2014-08-14 11:59:20 +04:00
mmu.c	xtensa: allow fixmap and kmap span more than one page table	2014-08-14 11:59:18 +04:00
tlb.c	xtensa: optimize local_flush_tlb_kernel_range	2014-04-06 21:29:17 +04:00