提交 bf5421c3 编写于 作者: A Andi Kleen 提交者: Linus Torvalds

[PATCH] i386/x86-64: Don't call change_page_attr with a spinlock held

It's illegal because it can sleep.

Use a two step lookup scheme instead.  First look up the vm_struct, then
change the direct mapping, then finally unmap it.  That's ok because nobody
can change the particular virtual address range as long as the vm_struct is
still in the global list.

Also added some LinuxDoc documentation to iounmap.
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
上级 5e9ef02e
......@@ -223,9 +223,15 @@ void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
}
EXPORT_SYMBOL(ioremap_nocache);
/**
* iounmap - Free a IO remapping
* @addr: virtual address from ioremap_*
*
* Caller must ensure there is only one unmapping for the same pointer.
*/
void iounmap(volatile void __iomem *addr)
{
struct vm_struct *p;
struct vm_struct *p, *o;
if ((void __force *)addr <= high_memory)
return;
......@@ -239,22 +245,37 @@ void iounmap(volatile void __iomem *addr)
addr < phys_to_virt(ISA_END_ADDRESS))
return;
write_lock(&vmlist_lock);
p = __remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
if (!p) {
printk(KERN_WARNING "iounmap: bad address %p\n", addr);
addr = (volatile void *)(PAGE_MASK & (unsigned long __force)addr);
/* Use the vm area unlocked, assuming the caller
ensures there isn't another iounmap for the same address
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);
if (!p) {
printk("iounmap: bad address %p\n", addr);
dump_stack();
goto out_unlock;
return;
}
/* Reset the direct mapping. Can block */
if ((p->flags >> 20) && p->phys_addr < virt_to_phys(high_memory) - 1) {
change_page_attr(virt_to_page(__va(p->phys_addr)),
p->size >> PAGE_SHIFT,
PAGE_KERNEL);
global_flush_tlb();
}
out_unlock:
write_unlock(&vmlist_lock);
/* Finally remove it */
o = remove_vm_area((void *)addr);
BUG_ON(p != o || o == NULL);
kfree(p);
}
EXPORT_SYMBOL(iounmap);
......
......@@ -247,9 +247,15 @@ void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
return __ioremap(phys_addr, size, _PAGE_PCD);
}
/**
* iounmap - Free a IO remapping
* @addr: virtual address from ioremap_*
*
* Caller must ensure there is only one unmapping for the same pointer.
*/
void iounmap(volatile void __iomem *addr)
{
struct vm_struct *p;
struct vm_struct *p, *o;
if (addr <= high_memory)
return;
......@@ -257,12 +263,31 @@ void iounmap(volatile void __iomem *addr)
addr < phys_to_virt(ISA_END_ADDRESS))
return;
write_lock(&vmlist_lock);
p = __remove_vm_area((void *)((unsigned long)addr & PAGE_MASK));
if (!p)
addr = (volatile void *)(PAGE_MASK & (unsigned long __force)addr);
/* Use the vm area unlocked, assuming the caller
ensures there isn't another iounmap for the same address
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);
if (!p) {
printk("iounmap: bad address %p\n", addr);
else if (p->flags >> 20)
dump_stack();
return;
}
/* Reset the direct mapping. Can block */
if (p->flags >> 20)
ioremap_change_attr(p->phys_addr, p->size, 0);
write_unlock(&vmlist_lock);
/* Finally remove it */
o = remove_vm_area((void *)addr);
BUG_ON(p != o || o == NULL);
kfree(p);
}
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