sys/dev/drm/include/linux/pagemap.h

   1 /*
   2  * Copyright (c) 2015 François Tigeot
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #ifndef _LINUX_PAGEMAP_H_
  28 #define _LINUX_PAGEMAP_H_
  29
  30 #include <linux/mm.h>
  31 #include <linux/list.h>
  32 #include <linux/highmem.h>
  33 #include <linux/compiler.h>
  34 #include <asm/uaccess.h>
  35 #include <linux/gfp.h>
  36 #include <linux/bitops.h>
  37 #include <linux/hardirq.h>
  38
  39 static inline int
  40 fault_in_multipages_writeable(char __user *uaddr, int size)
  41 {
  42         int ret = 0;
  43         char __user *end = uaddr + size - 1;
  44
  45         if (unlikely(size == 0))
  46                 return ret;
  47
  48         /*
  49          * Writing zeroes into userspace here is OK, because we know that if
  50          * the zero gets there, we'll be overwriting it.
  51          */
  52         while (uaddr <= end) {
  53                 ret = subyte(uaddr, 0);
  54                 if (ret != 0)
  55                         return -EFAULT;
  56                 uaddr += PAGE_SIZE;
  57         }
  58
  59         /* Check whether the range spilled into the next page. */
  60         if (((unsigned long)uaddr & ~PAGE_MASK) ==
  61                         ((unsigned long)end & ~PAGE_MASK))
  62                 ret = subyte(end, 0);
  63
  64         return ret;
  65 }
  66
  67 static inline int
  68 fault_in_multipages_readable(const char __user *uaddr, int size)
  69 {
  70         char c;
  71         int ret = 0;
  72         const char __user *end = uaddr + size - 1;
  73
  74         if (unlikely(size == 0))
  75                 return ret;
  76
  77         while (uaddr <= end) {
  78                 ret = -copyin(uaddr, &c, 1);
  79                 if (ret != 0)
  80                         return -EFAULT;
  81                 uaddr += PAGE_SIZE;
  82         }
  83
  84         /* Check whether the range spilled into the next page. */
  85         if (((unsigned long)uaddr & ~PAGE_MASK) ==
  86                         ((unsigned long)end & ~PAGE_MASK)) {
  87                 ret = -copyin(end, &c, 1);
  88         }
  89
  90         return ret;
  91 }
  92
  93 #endif  /* _LINUX_PAGEMAP_H_ */