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1b2ff639ff
We introduced a couple of helpers for copying iomem over iov_iter, and the functions were formed like the former copy_from/to_user(), and the return value was adjusted to 0/-EFAULT, which made the code transition a bit easier at that time. OTOH, the standard copy_from/to_iter() functions have different argument orders and the return value, and this difference can be confusing. It's not only confusing but dangerous; actually I did write a wrong code due to that once :-< For reducing the confusion, this patch changes the syntax of those helpers to align with the standard copy_from/to_iter(). The argument order is changed and the return value is the size of copied bytes. The callers of those functions are updated accordingly, too. Link: https://patch.msgid.link/20241230114903.4959-1-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
127 lines
3.1 KiB
C
127 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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*
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* Misc memory accessors
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*/
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#include <linux/export.h>
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#include <linux/io.h>
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#include <linux/uaccess.h>
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#include <sound/core.h>
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#include <sound/pcm.h>
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/**
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* copy_to_user_fromio - copy data from mmio-space to user-space
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* @dst: the destination pointer on user-space
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* @src: the source pointer on mmio
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* @count: the data size to copy in bytes
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*
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* Copies the data from mmio-space to user-space.
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*
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* Return: Zero if successful, or non-zero on failure.
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*/
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int copy_to_user_fromio(void __user *dst, const volatile void __iomem *src, size_t count)
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{
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struct iov_iter iter;
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if (import_ubuf(ITER_DEST, dst, count, &iter))
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return -EFAULT;
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if (copy_to_iter_fromio((const void __iomem *)src, count, &iter) != count)
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return -EFAULT;
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return 0;
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}
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EXPORT_SYMBOL(copy_to_user_fromio);
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/**
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* copy_to_iter_fromio - copy data from mmio-space to iov_iter
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* @src: the source pointer on mmio
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* @count: the data size to copy in bytes
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* @dst: the destination iov_iter
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*
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* Copies the data from mmio-space to iov_iter.
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*
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* Return: number of bytes to be copied
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*/
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size_t copy_to_iter_fromio(const void __iomem *src, size_t count,
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struct iov_iter *dst)
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{
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#if defined(__i386__) || defined(CONFIG_SPARC32)
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return copy_to_iter((const void __force *)src, count, dst);
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#else
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char buf[256];
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size_t res = 0;
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while (count) {
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size_t c = count;
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if (c > sizeof(buf))
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c = sizeof(buf);
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memcpy_fromio(buf, (void __iomem *)src, c);
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if (copy_to_iter(buf, c, dst) != c)
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return res;
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count -= c;
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src += c;
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res += c;
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}
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return res;
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#endif
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}
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EXPORT_SYMBOL(copy_to_iter_fromio);
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/**
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* copy_from_user_toio - copy data from user-space to mmio-space
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* @dst: the destination pointer on mmio-space
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* @src: the source pointer on user-space
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* @count: the data size to copy in bytes
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*
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* Copies the data from user-space to mmio-space.
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*
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* Return: Zero if successful, or non-zero on failure.
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*/
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int copy_from_user_toio(volatile void __iomem *dst, const void __user *src, size_t count)
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{
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struct iov_iter iter;
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if (import_ubuf(ITER_SOURCE, (void __user *)src, count, &iter))
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return -EFAULT;
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if (copy_from_iter_toio((void __iomem *)dst, count, &iter) != count)
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return -EFAULT;
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return 0;
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}
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EXPORT_SYMBOL(copy_from_user_toio);
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/**
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* copy_from_iter_toio - copy data from iov_iter to mmio-space
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* @dst: the destination pointer on mmio-space
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* @count: the data size to copy in bytes
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* @src: the source iov_iter
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*
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* Copies the data from iov_iter to mmio-space.
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*
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* Return: number of bytes to be copied
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*/
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size_t copy_from_iter_toio(void __iomem *dst, size_t count,
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struct iov_iter *src)
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{
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#if defined(__i386__) || defined(CONFIG_SPARC32)
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return copy_from_iter((void __force *)dst, count, src);
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#else
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char buf[256];
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size_t res = 0;
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while (count) {
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size_t c = count;
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if (c > sizeof(buf))
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c = sizeof(buf);
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if (copy_from_iter(buf, c, src) != c)
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return res;
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memcpy_toio(dst, buf, c);
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count -= c;
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dst += c;
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res += c;
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}
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return res;
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#endif
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}
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EXPORT_SYMBOL(copy_from_iter_toio);
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