Commit 561b4fa9 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

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: default avatarTakashi Iwai <tiwai@suse.de>
parent cf393bab

include/sound/pcm.h

+5 −0
Original line number Diff line number Diff line
@@ -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];

sound/core/memory.c

+48 −8
Original line number Diff line number Diff line
@@ -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);