On Fri, Dec 7, 2012 at 3:44 PM, Pekka Enberg <penberg at kernel.org> wrote:
> On Thu, Dec 6, 2012 at 6:09 PM, Joonsoo Kim <js1304 at gmail.com> wrote:
>> The purpose of iterating a vmlist is finding vm area with specific
>> virtual address. find_vm_area() is provided for this purpose
>> and more efficient, because it uses a rbtree.
>> So change it.
>
> You no longer take the 'vmlist_lock'. This is safe, because...?
>
I think it's because find_vm_area() -> find_vmap_area() will use
vmap_area_lock instead.
>> Cc: Chris Metcalf <cmetcalf at tilera.com>
>> Cc: Guan Xuetao <gxt at mprc.pku.edu.cn>
>> Cc: Thomas Gleixner <tglx at linutronix.de>
>> Cc: Ingo Molnar <mingo at redhat.com>
>> Cc: "H. Peter Anvin" <hpa at zytor.com>
>> Signed-off-by: Joonsoo Kim <js1304 at gmail.com>
>>
>> diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c
>> index de0de0c..862782d 100644
>> --- a/arch/tile/mm/pgtable.c
>> +++ b/arch/tile/mm/pgtable.c
>> @@ -592,12 +592,7 @@ void iounmap(volatile void __iomem *addr_in)
>> in parallel. Reuse of the virtual address is prevented by
>> leaving it in the global lists until we're done with it.
>> cpa takes care of the direct mappings. */
>> - read_lock(&vmlist_lock);
>> - for (p = vmlist; p; p = p->next) {
>> - if (p->addr == addr)
>> - break;
>> - }
>> - read_unlock(&vmlist_lock);
>> + p = find_vm_area((void *)addr);
>>
>> if (!p) {
>> pr_err("iounmap: bad address %p\n", addr);
>> diff --git a/arch/unicore32/mm/ioremap.c b/arch/unicore32/mm/ioremap.c
>> index b7a6055..13068ee 100644
>> --- a/arch/unicore32/mm/ioremap.c
>> +++ b/arch/unicore32/mm/ioremap.c
>> @@ -235,7 +235,7 @@ EXPORT_SYMBOL(__uc32_ioremap_cached);
>> void __uc32_iounmap(volatile void __iomem *io_addr)
>> {
>> void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
>> - struct vm_struct **p, *tmp;
>> + struct vm_struct *vm;
>>
>> /*
>> * If this is a section based mapping we need to handle it
>> @@ -244,17 +244,10 @@ void __uc32_iounmap(volatile void __iomem *io_addr)
>> * all the mappings before the area can be reclaimed
>> * by someone else.
>> */
>> - write_lock(&vmlist_lock);
>> - for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
>> - if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {
>> - if (tmp->flags & VM_UNICORE_SECTION_MAPPING) {
>> - unmap_area_sections((unsigned long)tmp->addr,
>> - tmp->size);
>> - }
>> - break;
>> - }
>> - }
>> - write_unlock(&vmlist_lock);
>> + vm = find_vm_area(addr);
>> + if (vm && (vm->flags & VM_IOREMAP) &&
>> + (vm->flags & VM_UNICORE_SECTION_MAPPING))
>> + unmap_area_sections((unsigned long)vm->addr, vm->size);
>>
>> vunmap(addr);
>> }
>> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
>> index 78fe3f1..9a1e658 100644
>> --- a/arch/x86/mm/ioremap.c
>> +++ b/arch/x86/mm/ioremap.c
>> @@ -282,12 +282,7 @@ void iounmap(volatile void __iomem *addr)
>> in parallel. Reuse of the virtual address is prevented by
>> leaving it in the global lists until we're done with it.
>> cpa takes care of the direct mappings. */
>> - read_lock(&vmlist_lock);
>> - for (p = vmlist; p; p = p->next) {
>> - if (p->addr == (void __force *)addr)
>> - break;
>> - }
>> - read_unlock(&vmlist_lock);
>> + p = find_vm_area((void __force *)addr);
>>
>> if (!p) {
>> printk(KERN_ERR "iounmap: bad address %p\n", addr);
>> --
>> 1.7.9.5
--
Thanks,
--Bob
