/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (C) IBM Corporation, 2010
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*
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* Author: Anton Blanchard <anton@au.ibm.com>
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*/
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#include <linux/export.h>
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include <asm/checksum.h>
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#include <linux/uaccess.h>
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__wsum csum_and_copy_from_user(const void __user *src, void *dst,
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int len, __wsum sum, int *err_ptr)
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{
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unsigned int csum;
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might_sleep();
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allow_read_from_user(src, len);
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*err_ptr = 0;
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if (!len) {
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csum = 0;
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goto out;
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}
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if (unlikely((len < 0) || !access_ok(VERIFY_READ, src, len))) {
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*err_ptr = -EFAULT;
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csum = (__force unsigned int)sum;
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goto out;
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}
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csum = csum_partial_copy_generic((void __force *)src, dst,
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len, sum, err_ptr, NULL);
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if (unlikely(*err_ptr)) {
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int missing = __copy_from_user(dst, src, len);
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if (missing) {
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memset(dst + len - missing, 0, missing);
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*err_ptr = -EFAULT;
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} else {
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*err_ptr = 0;
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}
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csum = csum_partial(dst, len, sum);
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}
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out:
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prevent_read_from_user(src, len);
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return (__force __wsum)csum;
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}
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EXPORT_SYMBOL(csum_and_copy_from_user);
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__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
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__wsum sum, int *err_ptr)
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{
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unsigned int csum;
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might_sleep();
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allow_write_to_user(dst, len);
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*err_ptr = 0;
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if (!len) {
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csum = 0;
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goto out;
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}
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if (unlikely((len < 0) || !access_ok(VERIFY_WRITE, dst, len))) {
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*err_ptr = -EFAULT;
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csum = -1; /* invalid checksum */
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goto out;
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}
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csum = csum_partial_copy_generic(src, (void __force *)dst,
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len, sum, NULL, err_ptr);
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if (unlikely(*err_ptr)) {
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csum = csum_partial(src, len, sum);
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if (copy_to_user(dst, src, len)) {
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*err_ptr = -EFAULT;
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csum = -1; /* invalid checksum */
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}
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}
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out:
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prevent_write_to_user(dst, len);
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return (__force __wsum)csum;
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}
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EXPORT_SYMBOL(csum_and_copy_to_user);
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