staging: gasket: gasket_mmap use PAGE_MASK

gasket_mmap use PAGE_MASK, instead of performing math on PAGE_SIZE, for
simplicity and clarity.

Reported-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Simon Que <sque@chromium.org>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/gasket/gasket_core.c b/drivers/staging/gasket/gasket_core.c
index 3cf918f..ae5febe 100644 (file)
--- a/drivers/staging/gasket/gasket_core.c
+++ b/drivers/staging/gasket/gasket_core.c
@@ -1591,7 +1591,7 @@ static int gasket_mmap(struct file *filp, struct vm_area_struct *vma)
        }
        driver_desc = gasket_dev->internal_desc->driver_desc;
 
-       if (vma->vm_start & (PAGE_SIZE - 1)) {
+       if (vma->vm_start & ~PAGE_MASK) {
                gasket_log_error(
                        gasket_dev, "Base address not page-aligned: 0x%p\n",
                        (void *)vma->vm_start);