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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: Nicolas Pitre <nicolas.pitre@linaro.org>
This commit is contained in:
Nicolas Pitre 2011-09-15 22:12:19 -04:00 committed by Nicolas Pitre
parent 0536bdf33f
commit 6ee723a657
1 changed files with 9 additions and 11 deletions
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20
arch/arm/mm/ioremap.c
View File

@ -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);