patch-2.3.6 linux/arch/i386/mm/ioremap.c

• Lines: 35
• Date: Thu Jun 3 14:17:51 1999
• Orig file: v2.3.5/linux/arch/i386/mm/ioremap.c
• Orig date: Fri Nov 27 15:03:14 1998

diff -u --recursive --new-file v2.3.5/linux/arch/i386/mm/ioremap.c linux/arch/i386/mm/ioremap.c
@@ -93,12 +93,17 @@
 {
 	void * addr;
 	struct vm_struct * area;
-	unsigned long offset;
+	unsigned long offset, last_addr;
+
+	/* Don't allow wraparound or zero size */
+	last_addr = phys_addr + size - 1;
+	if (!size || last_addr < phys_addr)
+		return NULL;
 
 	/*
 	 * Don't remap the low PCI/ISA area, it's always mapped..
 	 */
-	if (phys_addr >= 0xA0000 && (phys_addr+size) <= 0x100000)
+	if (phys_addr >= 0xA0000 && last_addr < 0x100000)
 		return phys_to_virt(phys_addr);
 
 	/*
@@ -112,13 +117,7 @@
 	 */
 	offset = phys_addr & ~PAGE_MASK;
 	phys_addr &= PAGE_MASK;
-	size = PAGE_ALIGN(size + offset);
-
-	/*
-	 * Don't allow mappings that wrap..
-	 */
-	if (!size || size > phys_addr + size)
-		return NULL;
+	size = PAGE_ALIGN(last_addr) - phys_addr;
 
 	/*
 	 * Ok, go for it..