From 6aa806ba10b4c9514386dbe131b6ff6c17a3dd8b Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@suse.de>
Date: Mon, 12 Dec 2005 22:17:09 -0800
Subject: [PATCH] --- yaml --- r: 15093 b: refs/heads/master c:
 bf5421c309bb89e5106452bc840983b1b4754d61 h: refs/heads/master i:   15091:
 dcd9490b2c23df6e9fbcc906743185666f304615 v: v3

---
 [refs]                         |  2 +-
 trunk/arch/i386/mm/ioremap.c   | 37 ++++++++++++++++++++++++++--------
 trunk/arch/x86_64/mm/ioremap.c | 37 ++++++++++++++++++++++++++++------
 3 files changed, 61 insertions(+), 15 deletions(-)

diff --git a/[refs] b/[refs]
index a85ef1f730f0..375e11872dac 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5e9ef02ec00c70840661d174dc2f4862db471bb6
+refs/heads/master: bf5421c309bb89e5106452bc840983b1b4754d61
diff --git a/trunk/arch/i386/mm/ioremap.c b/trunk/arch/i386/mm/ioremap.c
index 5d09de8d1c6b..8498b5ac3955 100644
--- a/trunk/arch/i386/mm/ioremap.c
+++ b/trunk/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 *)(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);
diff --git a/trunk/arch/x86_64/mm/ioremap.c b/trunk/arch/x86_64/mm/ioremap.c
index ecf7acb5db9b..0d260e4492f7 100644
--- a/trunk/arch/x86_64/mm/ioremap.c
+++ b/trunk/arch/x86_64/mm/ioremap.c
@@ -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); 
 }