[ARM] fix section-based ioremap

Tomi Valkeinen reports:
  Running with latest linux-omap kernel on OMAP3 SDP board, I have
  problem with iounmap(). It looks like iounmap() does not properly
  free large areas. Below is a test which fails for me in 6-7 loops.

	for (i = 0; i < 200; ++i) {
		vaddr = ioremap(paddr, size);
		if (!vaddr) {
			printk("couldn't ioremap\n");
			break;
		}
		iounmap(vaddr);
	}

The changes to vmalloc.c weren't reflected in the ARM ioremap
implementation.  Turns out the fix is rather simple.

Tested-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
Tested-by: Matt Gerassimoff <mgeras@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/ioremap.c

@@ -138,7 +138,7 @@ void __check_kvm_seq(struct mm_struct *mm)
  */
 static void unmap_area_sections(unsigned long virt, unsigned long size)
 {
-	unsigned long addr = virt, end = virt + (size & ~SZ_1M);
+	unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
 	pgd_t *pgd;
 
 	flush_cache_vunmap(addr, end);
@@ -337,10 +337,7 @@ void __iounmap(volatile void __iomem *io_addr)
 	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
 #ifndef CONFIG_SMP
 	struct vm_struct **p, *tmp;
-#endif
-	unsigned int section_mapping = 0;
 
-#ifndef CONFIG_SMP
 	/*
 	 * If this is a section based mapping we need to handle it
 	 * specially as the VM subsystem does not know how to handle
@@ -352,11 +349,8 @@ void __iounmap(volatile void __iomem *io_addr)
 	for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
 		if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {
 			if (tmp->flags & VM_ARM_SECTION_MAPPING) {
-				*p = tmp->next;
 				unmap_area_sections((unsigned long)tmp->addr,
 						    tmp->size);
-				kfree(tmp);
-				section_mapping = 1;
 			}
 			break;
 		}
@@ -364,7 +358,6 @@ void __iounmap(volatile void __iomem *io_addr)
 	write_unlock(&vmlist_lock);
 #endif
 
-	if (!section_mapping)
-		vunmap(addr);
+	vunmap(addr);
 }
 EXPORT_SYMBOL(__iounmap);