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ALSA: core: Add memory copy helpers between iov_iter and iomem 

Add two more helpers for copying memory between iov_iter and iomem,
which will be used by the new PCM copy ops in a few drivers.
The existing helpers became wrappers of those now.

Note that copy_from/to_iter() returns the copied bytes, hence the
error condition is adjusted accordingly.

Link: https://lore.kernel.org/r/20230815190136.8987-4-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2023-08-15 21:01:14 +02:00
parent cf393babb3
commit 561b4fa9c1
2 changed files with 53 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/sound/pcm.h
View File

@ -1559,6 +1559,11 @@ static inline u64 pcm_format_to_bits(snd_pcm_format_t pcm_format)
#define pcm_dbg(pcm, fmt, args...) \
dev_dbg((pcm)->card->dev, fmt, ##args)
/* helpers for copying between iov_iter and iomem */
int copy_to_iter_fromio(struct iov_iter *itert, const void __iomem *src,
size_t count);
int copy_from_iter_toio(void __iomem *dst, struct iov_iter *iter, size_t count);
struct snd_pcm_status64 {
snd_pcm_state_t state; /* stream state */
u8 rsvd[4];

56
sound/core/memory.c
View File

@ -9,6 +9,7 @@
#include <linux/io.h>
#include <linux/uaccess.h>
#include <sound/core.h>
#include <sound/pcm.h>
/**
* copy_to_user_fromio - copy data from mmio-space to user-space
@ -21,9 +22,30 @@
* Return: Zero if successful, or non-zero on failure.
*/
int copy_to_user_fromio(void __user *dst, const volatile void __iomem *src, size_t count)
{
struct iov_iter iter;
if (import_ubuf(ITER_DEST, dst, count, &iter))
return -EFAULT;
return copy_to_iter_fromio(&iter, (const void __iomem *)src, count);
}
EXPORT_SYMBOL(copy_to_user_fromio);
/**
* copy_to_iter_fromio - copy data from mmio-space to iov_iter
* @dst: the destination iov_iter
* @src: the source pointer on mmio
* @count: the data size to copy in bytes
*
* Copies the data from mmio-space to iov_iter.
*
* Return: Zero if successful, or non-zero on failure.
*/
int copy_to_iter_fromio(struct iov_iter *dst, const void __iomem *src,
size_t count)
{
#if defined(__i386__) || defined(CONFIG_SPARC32)
return copy_to_user(dst, (const void __force*)src, count) ? -EFAULT : 0;
return copy_to_iter((const void __force *)src, count, dst) == count ? 0 : -EFAULT;
#else
char buf[256];
while (count) {
@ -31,16 +53,15 @@ int copy_to_user_fromio(void __user *dst, const volatile void __iomem *src, size
if (c > sizeof(buf))
c = sizeof(buf);
memcpy_fromio(buf, (void __iomem *)src, c);
if (copy_to_user(dst, buf, c))
if (copy_to_iter(buf, c, dst) != c)
return -EFAULT;
count -= c;
dst += c;
src += c;
}
return 0;
#endif
}
EXPORT_SYMBOL(copy_to_user_fromio);
EXPORT_SYMBOL(copy_to_iter_fromio);
/**
* copy_from_user_toio - copy data from user-space to mmio-space
@ -53,23 +74,42 @@ EXPORT_SYMBOL(copy_to_user_fromio);
* Return: Zero if successful, or non-zero on failure.
*/
int copy_from_user_toio(volatile void __iomem *dst, const void __user *src, size_t count)
{
struct iov_iter iter;
if (import_ubuf(ITER_SOURCE, (void __user *)src, count, &iter))
return -EFAULT;
return copy_from_iter_toio((void __iomem *)dst, &iter, count);
}
EXPORT_SYMBOL(copy_from_user_toio);
/**
* copy_from_iter_toio - copy data from iov_iter to mmio-space
* @dst: the destination pointer on mmio-space
* @src: the source iov_iter
* @count: the data size to copy in bytes
*
* Copies the data from iov_iter to mmio-space.
*
* Return: Zero if successful, or non-zero on failure.
*/
int copy_from_iter_toio(void __iomem *dst, struct iov_iter *src, size_t count)
{
#if defined(__i386__) || defined(CONFIG_SPARC32)
return copy_from_user((void __force *)dst, src, count) ? -EFAULT : 0;
return copy_from_iter((void __force *)dst, count, src) == count ? 0 : -EFAULT;
#else
char buf[256];
while (count) {
size_t c = count;
if (c > sizeof(buf))
c = sizeof(buf);
if (copy_from_user(buf, src, c))
if (copy_from_iter(buf, c, src) != c)
return -EFAULT;
memcpy_toio(dst, buf, c);
count -= c;
dst += c;
src += c;
}
return 0;
#endif
}
EXPORT_SYMBOL(copy_from_user_toio);
EXPORT_SYMBOL(copy_from_iter_toio);