x86-decouple-page-fault-logic

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/mm/fault.c

@@ -1032,7 +1032,7 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
 	 * If we're in an interrupt, have no user context or are running
 	 * in an atomic region then we must not take the fault:
 	 */
-	if (unlikely(in_atomic() || !mm)) {
+	if (unlikely(in_atomic() || !mm || current->pagefault_disabled)) {
 		bad_area_nosemaphore(regs, error_code, address);
 		return;
 	}

arch/x86/mm/iomap_32.c

@@ -37,6 +37,7 @@ void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
 	enum fixed_addresses idx;
 	unsigned long vaddr;
 
+	preempt_disable();
 	pagefault_disable();
 
 	debug_kmap_atomic(type);
@@ -83,5 +84,6 @@ iounmap_atomic(void *kvaddr, enum km_type type)
 		kpte_clear_flush(kmap_pte-idx, vaddr);
 
 	pagefault_enable();
+	preempt_enable();
 }
 EXPORT_SYMBOL_GPL(iounmap_atomic);