diff options
| author | Wu Fengguang <fengguang.wu@intel.com> | 2010-02-05 15:00:52 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-02-23 07:37:54 -0800 |
| commit | 0e1104ada32d242bc6169a2ce4eb19ec4febb813 (patch) | |
| tree | b88ece901a05b130a94852d230665ae980bf5c77 /drivers/char | |
| parent | 06eeea406c93680a55dd333971638af7289f8f7b (diff) | |
/dev/mem: introduce size_inside_page()
commit f222318e9c3a315723e3524fb9d6566b2430db44 upstream
/dev/mem: introduce size_inside_page()
[ cebbert@redhat.com : backport to 2.6.32 ]
[ subset of original patch, for just /dev/kmem ]
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>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/mem.c | 40 |
1 files changed, 17 insertions, 23 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index a074fceb67d3..1ffb6dd3eae4 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -35,6 +35,19 @@ # 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. @@ -430,15 +443,7 @@ 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 @@ -462,10 +467,8 @@ 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; @@ -510,15 +513,8 @@ 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 @@ -578,10 +574,8 @@ 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; if (len) { written = copy_from_user(kbuf, buf, len); if (written) { |