[PATCH] parisc: Fix vmap memory leak in ioremap()/iounmap()

[Helge Deller <deller@gmx.de>]

Sven noticed that calling ioremap() and iounmap() multiple times leads
to a vmap memory leak:
	vmap allocation for size 4198400 failed:
	use vmalloc=<size> to increase size

It seems we missed calling remove_vm_area() for ioummap().

Signed-off-by: Helge Deller <deller@gmx.de>
Noticed-by: Sven Schnelle <svens@stackframe.org>
Cc: <stable@vger.kernel.org>

diff --git a/arch/parisc/mm/ioremap.c b/arch/parisc/mm/ioremap.c
index 92a9b5f12f98..bcfa98aa134c 100644
--- a/arch/parisc/mm/ioremap.c
+++ b/arch/parisc/mm/ioremap.c
@@ -3,13 +3,14 @@
  * arch/parisc/mm/ioremap.c
  *
  * (C) Copyright 1995 1996 Linus Torvalds
- * (C) Copyright 2001-2006 Helge Deller <deller@gmx.de>
+ * (C) Copyright 2001-2019 Helge Deller <deller@gmx.de>
  * (C) Copyright 2005 Kyle McMartin <kyle@parisc-linux.org>
  */

 #include <linux/vmalloc.h>
 #include <linux/errno.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 #include <linux/io.h>
 #include <asm/pgalloc.h>

@@ -84,7 +85,8 @@ void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned l
 	addr = (void __iomem *) area->addr;
 	if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
 			       phys_addr, pgprot)) {
-		vfree(addr);
+		remove_vm_area((void __force *)addr);
+		kfree(area);
 		return NULL;
 	}

@@ -94,7 +96,24 @@ EXPORT_SYMBOL(__ioremap);

 void iounmap(const volatile void __iomem *addr)
 {
-	if (addr > high_memory)
-		return vfree((void *) (PAGE_MASK & (unsigned long __force) addr));
+	struct vm_struct *p, *o;
+
+	if (addr <= high_memory)
+		return;
+
+	addr = (volatile void __iomem *)
+		(PAGE_MASK & (unsigned long __force)addr);
+
+	p = find_vm_area((void __force *)addr);
+	if (!p) {
+		printk(KERN_ERR "iounmap: bad address %p\n", addr);
+		dump_stack();
+		return;
+	}
+
+	/* Finally remove it */
+	o = remove_vm_area((void __force *)addr);
+	BUG_ON(p != o || o == NULL);
+	kfree(p);
 }
 EXPORT_SYMBOL(iounmap);