Commit ea46f797 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: seq: Add snd_seq_expand_var_event_at() helper 



Create a new variant of snd_seq_expand_var_event() for expanding the
data starting from the given byte offset.  It'll be used by the new
UMP sequencer code later.

Reviewed-by: default avatarJaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-19-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent f80e6d60

include/sound/seq_kernel.h

+2 −0
Original line number Diff line number Diff line
@@ -70,6 +70,8 @@ int snd_seq_kernel_client_ctl(int client, unsigned int cmd, void *arg); 
typedef int (*snd_seq_dump_func_t)(void *ptr, void *buf, int count);

int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char *buf,

			     int in_kernel, int size_aligned);

int snd_seq_expand_var_event_at(const struct snd_seq_event *event, int count,

				char *buf, int offset);

int snd_seq_dump_var_event(const struct snd_seq_event *event,

			   snd_seq_dump_func_t func, void *private_data);

sound/core/seq/seq_memory.c

+67 −19
Original line number Diff line number Diff line
@@ -63,8 +63,9 @@ static int get_var_len(const struct snd_seq_event *event) 
	return event->data.ext.len & ~SNDRV_SEQ_EXT_MASK;

}



int snd_seq_dump_var_event(const struct snd_seq_event *event,

			   snd_seq_dump_func_t func, void *private_data)

static int dump_var_event(const struct snd_seq_event *event,

			  snd_seq_dump_func_t func, void *private_data,

			  int offset, int maxlen)

{

	int len, err;

	struct snd_seq_event_cell *cell;
@@ -72,10 +73,16 @@ int snd_seq_dump_var_event(const struct snd_seq_event *event, 
	len = get_var_len(event);

	if (len <= 0)

		return len;

	if (len <= offset)

		return 0;

	if (maxlen && len > offset + maxlen)

		len = offset + maxlen;



	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {

		char buf[32];

		char __user *curptr = (char __force __user *)event->data.ext.ptr;

		curptr += offset;

		len -= offset;

		while (len > 0) {

			int size = sizeof(buf);

			if (len < size)
@@ -91,20 +98,35 @@ int snd_seq_dump_var_event(const struct snd_seq_event *event, 
		return 0;

	}

	if (!(event->data.ext.len & SNDRV_SEQ_EXT_CHAINED))

		return func(private_data, event->data.ext.ptr, len);

		return func(private_data, event->data.ext.ptr + offset,

			    len - offset);



	cell = (struct snd_seq_event_cell *)event->data.ext.ptr;

	for (; len > 0 && cell; cell = cell->next) {

		int size = sizeof(struct snd_seq_event);

		char *curptr = (char *)&cell->event;



		if (offset >= size) {

			offset -= size;

			len -= size;

			continue;

		}

		if (len < size)

			size = len;

		err = func(private_data, &cell->event, size);

		err = func(private_data, curptr + offset, size - offset);

		if (err < 0)

			return err;

		offset = 0;

		len -= size;

	}

	return 0;

}



int snd_seq_dump_var_event(const struct snd_seq_event *event,

			   snd_seq_dump_func_t func, void *private_data)

{

	return dump_var_event(event, func, private_data, 0, 0);

}

EXPORT_SYMBOL(snd_seq_dump_var_event);
@@ -132,11 +154,27 @@ static int seq_copy_in_user(void *ptr, void *src, int size) 
	return 0;

}



static int expand_var_event(const struct snd_seq_event *event,

			    int offset, int size, char *buf, bool in_kernel)

{

	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {

		if (! in_kernel)

			return -EINVAL;

		if (copy_from_user(buf,

				   (char __force __user *)event->data.ext.ptr + offset,

				   size))

			return -EFAULT;

		return 0;

	}

	return dump_var_event(event,

			     in_kernel ? seq_copy_in_kernel : seq_copy_in_user,

			     &buf, offset, size);

}



int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char *buf,

			     int in_kernel, int size_aligned)

{

	int len, newlen;

	int err;

	int len, newlen, err;



	len = get_var_len(event);

	if (len < 0)
@@ -146,25 +184,35 @@ int snd_seq_expand_var_event(const struct snd_seq_event *event, int count, char 
		newlen = roundup(len, size_aligned);

	if (count < newlen)

		return -EAGAIN;



	if (event->data.ext.len & SNDRV_SEQ_EXT_USRPTR) {

		if (! in_kernel)

			return -EINVAL;

		if (copy_from_user(buf, (void __force __user *)event->data.ext.ptr, len))

			return -EFAULT;

	} else {

		err = snd_seq_dump_var_event(event,

					     in_kernel ? seq_copy_in_kernel : seq_copy_in_user,

					     &buf);

	err = expand_var_event(event, 0, len, buf, in_kernel);

	if (err < 0)

		return err;

	}

	if (len != newlen)

		memset(buf + len, 0, newlen - len);

	return newlen;

}

EXPORT_SYMBOL(snd_seq_expand_var_event);



int snd_seq_expand_var_event_at(const struct snd_seq_event *event, int count,

				char *buf, int offset)

{

	int len, err;



	len = get_var_len(event);

	if (len < 0)

		return len;

	if (len <= offset)

		return 0;

	len -= offset;

	if (len > count)

		len = count;

	err = expand_var_event(event, offset, count, buf, true);

	if (err < 0)

		return err;

	return len;

}

EXPORT_SYMBOL_GPL(snd_seq_expand_var_event_at);



/*

 * release this cell, free extended data if available

 */