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/dev/mem: introduce size_inside_page()

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Introduce size_inside_page() to replace duplicate /dev/mem code.

Also apply it to /dev/kmem, whose alignment logic was buggy.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Wu Fengguang 2009-12-14 17:58:07 -08:00 committed by Linus Torvalds
parent 4ea2f43f28
commit f222318e9c
1 changed files with 19 additions and 41 deletions
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60
drivers/char/mem.c
View file

@ -34,6 +34,19 @@
# include <linux/efi.h>
#endif
static inline unsigned long size_inside_page(unsigned long start,
unsigned long size)
{
unsigned long sz;
if (-start & (PAGE_SIZE - 1))
sz = -start & (PAGE_SIZE - 1);
else
sz = PAGE_SIZE;
return min_t(unsigned long, sz, size);
}
/*
* Architectures vary in how they handle caching for addresses
* outside of main memory.
@ -141,15 +154,7 @@ static ssize_t read_mem(struct file * file, char __user * buf,
#endif
while (count > 0) {
/*
* Handle first page in case it's not aligned
*/
if (-p & (PAGE_SIZE - 1))
sz = -p & (PAGE_SIZE - 1);
else
sz = PAGE_SIZE;
sz = min_t(unsigned long, sz, count);
sz = size_inside_page(p, count);
if (!range_is_allowed(p >> PAGE_SHIFT, count))
return -EPERM;
@ -208,15 +213,7 @@ static ssize_t write_mem(struct file * file, const char __user * buf,
#endif
while (count > 0) {
/*
* Handle first page in case it's not aligned
*/
if (-p & (PAGE_SIZE - 1))
sz = -p & (PAGE_SIZE - 1);
else
sz = PAGE_SIZE;
sz = min_t(unsigned long, sz, count);
sz = size_inside_page(p, count);
if (!range_is_allowed(p >> PAGE_SHIFT, sz))
return -EPERM;
@ -429,15 +426,7 @@ static ssize_t read_kmem(struct file *file, char __user *buf,
}
#endif
while (low_count > 0) {
/*
* Handle first page in case it's not aligned
*/
if (-p & (PAGE_SIZE - 1))
sz = -p & (PAGE_SIZE - 1);
else
sz = PAGE_SIZE;
sz = min_t(unsigned long, sz, low_count);
sz = size_inside_page(p, low_count);
/*
* On ia64 if a page has been mapped somewhere as
@ -461,10 +450,8 @@ static ssize_t read_kmem(struct file *file, char __user *buf,
if (!kbuf)
return -ENOMEM;
while (count > 0) {
int len = count;
int len = size_inside_page(p, count);
if (len > PAGE_SIZE)
len = PAGE_SIZE;
len = vread(kbuf, (char *)p, len);
if (!len)
break;
@ -509,15 +496,8 @@ do_write_kmem(void *p, unsigned long realp, const char __user * buf,
while (count > 0) {
char *ptr;
/*
* Handle first page in case it's not aligned
*/
if (-realp & (PAGE_SIZE - 1))
sz = -realp & (PAGE_SIZE - 1);
else
sz = PAGE_SIZE;
sz = min_t(unsigned long, sz, count);
sz = size_inside_page(realp, count);
/*
* On ia64 if a page has been mapped somewhere as
@ -577,10 +557,8 @@ static ssize_t write_kmem(struct file * file, const char __user * buf,
if (!kbuf)
return wrote ? wrote : -ENOMEM;
while (count > 0) {
int len = count;
int len = size_inside_page(p, count);
if (len > PAGE_SIZE)
len = PAGE_SIZE;
written = copy_from_user(kbuf, buf, len);
if (written) {
if (wrote + virtr)