diff options
| -rw-r--r-- | drivers/char/mem.c | 60 |
1 files changed, 19 insertions, 41 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index f0a90590cb1a..aaa9c24d4c14 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -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) |