From 2cb7c9cb426660b5ed58b643d9e7dd5d50ba901f Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 11 May 2015 17:52:09 +0200 Subject: sched/preempt, mm/kmap: Explicitly disable/enable preemption in kmap_atomic_* The existing code relies on pagefault_disable() implicitly disabling preemption, so that no schedule will happen between kmap_atomic() and kunmap_atomic(). Let's make this explicit, to prepare for pagefault_disable() not touching preemption anymore. Reviewed-and-tested-by: Thomas Gleixner Signed-off-by: David Hildenbrand Signed-off-by: Peter Zijlstra (Intel) Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner 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/1431359540-32227-5-git-send-email-dahi@linux.vnet.ibm.com Signed-off-by: Ingo Molnar --- arch/microblaze/mm/highmem.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/microblaze') diff --git a/arch/microblaze/mm/highmem.c b/arch/microblaze/mm/highmem.c index 5a92576fad92..2fcc5a52d84d 100644 --- a/arch/microblaze/mm/highmem.c +++ b/arch/microblaze/mm/highmem.c @@ -37,7 +37,7 @@ void *kmap_atomic_prot(struct page *page, pgprot_t prot) unsigned long vaddr; int idx, type; - /* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */ + preempt_disable(); pagefault_disable(); if (!PageHighMem(page)) return page_address(page); @@ -63,6 +63,7 @@ void __kunmap_atomic(void *kvaddr) if (vaddr < __fix_to_virt(FIX_KMAP_END)) { pagefault_enable(); + preempt_enable(); return; } @@ -84,5 +85,6 @@ void __kunmap_atomic(void *kvaddr) #endif kmap_atomic_idx_pop(); pagefault_enable(); + preempt_enable(); } EXPORT_SYMBOL(__kunmap_atomic); -- cgit v1.2.3