1 files changed, 20 insertions, 28 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 29c41f4418c..66719f9d294 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -88,21 +88,15 @@ static inline int uncached_access(struct file *file, unsigned long addr)
 }
 
 #ifndef ARCH_HAS_VALID_PHYS_ADDR_RANGE
-static inline int valid_phys_addr_range(unsigned long addr, size_t *count)
+static inline int valid_phys_addr_range(unsigned long addr, size_t count)
 {
-	unsigned long end_mem;
-
-	end_mem = __pa(high_memory);
-	if (addr >= end_mem)
+	if (addr + count > __pa(high_memory))
 		return 0;
 
-	if (*count > end_mem - addr)
-		*count = end_mem - addr;
-
 	return 1;
 }
 
-static inline int valid_mmap_phys_addr_range(unsigned long addr, size_t *size)
+static inline int valid_mmap_phys_addr_range(unsigned long addr, size_t size)
 {
 	return 1;
 }
@@ -119,7 +113,7 @@ static ssize_t read_mem(struct file * file, char __user * buf,
 	ssize_t read, sz;
 	char *ptr;
 
-	if (!valid_phys_addr_range(p, &count))
+	if (!valid_phys_addr_range(p, count))
 		return -EFAULT;
 	read = 0;
 #ifdef __ARCH_HAS_NO_PAGE_ZERO_MAPPED
@@ -177,7 +171,7 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
 	unsigned long copied;
 	void *ptr;
 
-	if (!valid_phys_addr_range(p, &count))
+	if (!valid_phys_addr_range(p, count))
 		return -EFAULT;
 
 	written = 0;
@@ -216,11 +210,9 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
 
 		copied = copy_from_user(ptr, buf, sz);
 		if (copied) {
-			ssize_t ret;
-
-			ret = written + (sz - copied);
-			if (ret)
-				return ret;
+			written += sz - copied;
+			if (written)
+				break;
 			return -EFAULT;
 		}
 		buf += sz;
@@ -251,7 +243,7 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 {
 	size_t size = vma->vm_end - vma->vm_start;
 
-	if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, &size))
+	if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, size))
 		return -EINVAL;
 
 	vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
@@ -456,11 +448,9 @@ do_write_kmem(void *p, unsigned long realp, const char __user * buf,
 
 		copied = copy_from_user(ptr, buf, sz);
 		if (copied) {
-			ssize_t ret;
-
-			ret = written + (sz - copied);
-			if (ret)
-				return ret;
+			written += sz - copied;
+			if (written)
+				break;
 			return -EFAULT;
 		}
 		buf += sz;
@@ -514,11 +504,10 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
 			if (len) {
 				written = copy_from_user(kbuf, buf, len);
 				if (written) {
-					ssize_t ret;
-
+					if (wrote + virtr)
+						break;
 					free_page((unsigned long)kbuf);
-					ret = wrote + virtr + (len - written);
-					return ret ? ret : -EFAULT;
+					return -EFAULT;
 				}
 			}
 			len = vwrite(kbuf, (char *)p, len);
@@ -563,8 +552,11 @@ static ssize_t write_port(struct file * file, const char __user * buf,
 		return -EFAULT;
 	while (count-- > 0 && i < 65536) {
 		char c;
-		if (__get_user(c, tmp)) 
+		if (__get_user(c, tmp)) {
+			if (tmp > buf)
+				break;
 			return -EFAULT; 
+		}
 		outb(c,i);
 		i++;
 		tmp++;
@@ -907,7 +899,7 @@ static const struct {
 	unsigned int		minor;
 	char			*name;
 	umode_t			mode;
-	struct file_operations	*fops;
+	const struct file_operations	*fops;
 } devlist[] = { /* list of minor devices */
 	{1, "mem",     S_IRUSR | S_IWUSR | S_IRGRP, &mem_fops},
 	{2, "kmem",    S_IRUSR | S_IWUSR | S_IRGRP, &kmem_fops},