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ALSA: seq: Add snd_seq_expand_var_event_at() helper

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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: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-19-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2023-05-23 09:53:39 +02:00
parent f80e6d60d6
commit ea46f79709
2 changed files with 69 additions and 19 deletions
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2
include/sound/seq_kernel.h
View File

@ -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);

86
sound/core/seq/seq_memory.c
View File

@ -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);
if (err < 0)
return err;
}
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
*/