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Commit 6ee723a6 authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Nicolas Pitre
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ARM: simplify __iounmap() when dealing with section based mapping 



Firstly, there is no need to have a double pointer here as we're only
walking the vmlist and not modifying it.

Secondly, for the same reason, we don't need a write lock but only a
read lock here, since the lock only protects the coherency of the list
nothing else.

Lastly, the reason for holding a lock is not what the comment says, so
let's remove that misleading piece of information.

Signed-off-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent 0536bdf3

arch/arm/mm/ioremap.c

+9 −11
Original line number Diff line number Diff line
@@ -314,26 +314,24 @@ void __iounmap(volatile void __iomem *io_addr) 
{

	void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);

#ifndef CONFIG_SMP

	struct vm_struct **p, *tmp;

	struct vm_struct *vm;



	/*

	 * If this is a section based mapping we need to handle it

	 * specially as the VM subsystem does not know how to handle

	 * such a beast. We need the lock here b/c we need to clear

	 * all the mappings before the area can be reclaimed

	 * by someone else.

	 * such a beast.

	 */

	write_lock(&vmlist_lock);

	for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {

		if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {

			if (tmp->flags & VM_ARM_SECTION_MAPPING) {

				unmap_area_sections((unsigned long)tmp->addr,

						    tmp->size);

	read_lock(&vmlist_lock);

	for (vm = vmlist; vm; vm = vm->next) {

		if ((vm->flags & VM_IOREMAP) && (vm->addr == addr)) {

			if (vm->flags & VM_ARM_SECTION_MAPPING) {

				unmap_area_sections((unsigned long)vm->addr,

						    vm->size);

			}

			break;

		}

	}

	write_unlock(&vmlist_lock);

	read_unlock(&vmlist_lock);

#endif



	vunmap(addr);