diff options
Diffstat (limited to 'arch/i386/mm/ioremap.c')
| -rw-r--r-- | arch/i386/mm/ioremap.c | 37 |
1 files changed, 29 insertions, 8 deletions
diff --git a/arch/i386/mm/ioremap.c b/arch/i386/mm/ioremap.c index 5d09de8d1c6b..247fde76aaed 100644 --- a/arch/i386/mm/ioremap.c +++ b/arch/i386/mm/ioremap.c @@ -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 __iomem *)(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); |