The branch releng/14.1 has been updated by christos:
URL:
https://cgit.FreeBSD.org/src/commit/?id=a4a473104ec4a42c66f1b9a09736954ebad43e7e
commit a4a473104ec4a42c66f1b9a09736954ebad43e7e
Author: Christos Margiolis <chris...@freebsd.org>
AuthorDate: 2024-05-09 19:07:48 +0000
Commit: Christos Margiolis <chris...@freebsd.org>
CommitDate: 2024-05-22 13:20:42 +0000
sound: Remove nmix variable from mixer_oss_mixerinfo()
nmix is used to compare against oss_mixerinfo->dev, which is a
user-supplied value to select the mixer device (if not -1, in which case
we'll select the default one) we want to fetch the information of. It is
also used to set oss_mixerinfo->dev in case it is -1.
However, nmix is at best redundant, since we have the loop counter
already (i), and confusing at worst.
For example, suppose a system with 3 mixer devices. We call
SNDCTL_MIXERINFO with oss_mixerinfo->dev=1, meaning we want to get
information for /dev/mixer1. Suppose /dev/mixer0 detaches while inside
the loop, so we'll hit the loop's "continue" case, and nmix won't get
incremented (i.e will stay 0 for now). At this point nmix counts 1
device less, so when it reaches 1, we'll be fetching /dev/mixer2's
information instead of /dev/mixer1's.
This is also true in case the mixer device disappears prior to the call
to mixer_oss_mixerinfo().
Simply remove nmix and use the loop counter to both set
oss_mixerinfo->dev and check against it in case a non -1 value is
supplied.
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Reviewed by: dev_submerge.ch
Differential Revision: https://reviews.freebsd.org/D45135
(cherry picked from commit 2f31a5eb75f1e47b5c49f574e8ce48d2c863e9d3)
(cherry picked from commit 8b4e2ba31d1b171f688cb630f1827ec397ecaacb)
Approved by: re (cperciva)
---
sys/dev/sound/pcm/mixer.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/sys/dev/sound/pcm/mixer.c b/sys/dev/sound/pcm/mixer.c
index 0645089ac503..31a633afb380 100644
--- a/sys/dev/sound/pcm/mixer.c
+++ b/sys/dev/sound/pcm/mixer.c
@@ -1430,7 +1430,7 @@ mixer_oss_mixerinfo(struct cdev *i_dev, oss_mixerinfo *mi)
{
struct snddev_info *d;
struct snd_mixer *m;
- int nmix, i;
+ int i;
/*
* If probing the device handling the ioctl, make sure it's a mixer
@@ -1441,7 +1441,6 @@ mixer_oss_mixerinfo(struct cdev *i_dev, oss_mixerinfo *mi)
d = NULL;
m = NULL;
- nmix = 0;
/*
* There's a 1:1 relationship between mixers and PCM devices, so
@@ -1461,7 +1460,7 @@ mixer_oss_mixerinfo(struct cdev *i_dev, oss_mixerinfo *mi)
if (d->mixer_dev != NULL && d->mixer_dev->si_drv1 != NULL &&
((mi->dev == -1 && d->mixer_dev == i_dev) ||
- mi->dev == nmix)) {
+ mi->dev == i)) {
m = d->mixer_dev->si_drv1;
mtx_lock(m->lock);
@@ -1473,7 +1472,7 @@ mixer_oss_mixerinfo(struct cdev *i_dev, oss_mixerinfo *mi)
* sure to unlock when existing.
*/
bzero((void *)mi, sizeof(*mi));
- mi->dev = nmix;
+ mi->dev = i;
snprintf(mi->id, sizeof(mi->id), "mixer%d", i);
strlcpy(mi->name, m->name, sizeof(mi->name));
mi->modify_counter = m->modify_counter;
@@ -1537,8 +1536,7 @@ mixer_oss_mixerinfo(struct cdev *i_dev, oss_mixerinfo *mi)
mi->legacy_device = i;
*/
mtx_unlock(m->lock);
- } else
- ++nmix;
+ }
PCM_UNLOCK(d);
