git: b4c32d67d40a - main - sound: Simplify logic in dsp_io_ops()

The branch main has been updated by christos:

URL: https://cgit.FreeBSD.org/src/commit/?id=b4c32d67d40a862620aa3e565ed0cb9ad59f1e60

commit b4c32d67d40a862620aa3e565ed0cb9ad59f1e60
Author:     Christos Margiolis <christos@FreeBSD.org>
AuthorDate: 2025-11-21 16:14:13 +0000
Commit:     Christos Margiolis <christos@FreeBSD.org>
CommitDate: 2025-11-21 16:14:13 +0000

    sound: Simplify logic in dsp_io_ops()
    
    Use CHN_LOCK()/CHN_UNLOCK() directly, instead of
    dsp_lock_chans()/dsp_unlock_chans(). These functions are useful when we
    want to potentially lock both channels. Here we know which channel we
    are locking, so we can just lock it directly. This way we get rid of the
    prio variable as well.
    
    Related to runpid again, there is no reason to assign it when
    CHN_F_RUNNING is not set. channel->pid (as well as channel->comm) is
    always assigned in dsp_chn_alloc().
    
    Get rid of runpid. I do not see how we can end up with channel->pid
    (td->td_proc->p_pid) not matching buf->uio_td->td_proc->p_pid.
    
    Also improve errno values.
    
    Sponsored by:   The FreeBSD Foundation
    MFC after:      1 week
    Reviewed by:    markj
    Differential Revision:  https://reviews.freebsd.org/D53736
---
 sys/dev/sound/pcm/dsp.c | 32 ++++++++++----------------------
 1 file changed, 10 insertions(+), 22 deletions(-)

diff --git a/sys/dev/sound/pcm/dsp.c b/sys/dev/sound/pcm/dsp.c
index 1ae090f252c2..cb8b5414973c 100644
--- a/sys/dev/sound/pcm/dsp.c
+++ b/sys/dev/sound/pcm/dsp.c
@@ -464,8 +464,7 @@ dsp_io_ops(struct dsp_cdevpriv *priv, struct uio *buf)
 	struct snddev_info *d;
 	struct pcm_channel *ch;
 	int (*chn_io)(struct pcm_channel *, struct uio *);
-	int prio, ret;
-	pid_t runpid;
+	int ret;
 
 	d = priv->sc;
 	if (!DSP_REGISTERED(d))
@@ -475,37 +474,27 @@ dsp_io_ops(struct dsp_cdevpriv *priv, struct uio *buf)
 
 	switch (buf->uio_rw) {
 	case UIO_READ:
-		prio = FREAD;
 		ch = priv->rdch;
 		chn_io = chn_read;
 		break;
 	case UIO_WRITE:
-		prio = FWRITE;
 		ch = priv->wrch;
 		chn_io = chn_write;
 		break;
 	}
-
-	runpid = buf->uio_td->td_proc->p_pid;
-
-	dsp_lock_chans(priv, prio);
-
-	if (ch == NULL || !(ch->flags & CHN_F_BUSY)) {
-		if (priv->rdch != NULL || priv->wrch != NULL)
-			dsp_unlock_chans(priv, prio);
+	if (ch == NULL) {
 		PCM_GIANT_EXIT(d);
-		return (EBADF);
+		return (ENXIO);
 	}
+	CHN_LOCK(ch);
 
-	if (ch->flags & (CHN_F_MMAP | CHN_F_DEAD) ||
-	    (ch->flags & CHN_F_RUNNING && ch->pid != runpid)) {
-		dsp_unlock_chans(priv, prio);
+	if (!(ch->flags & CHN_F_BUSY) ||
+	    (ch->flags & (CHN_F_MMAP | CHN_F_DEAD))) {
+		CHN_UNLOCK(ch);
 		PCM_GIANT_EXIT(d);
-		return (EINVAL);
-	} else if (!(ch->flags & CHN_F_RUNNING)) {
+		return (ENXIO);
+	} else if (!(ch->flags & CHN_F_RUNNING))
 		ch->flags |= CHN_F_RUNNING;
-		ch->pid = runpid;
-	}
 
 	/*
 	 * chn_read/write must give up channel lock in order to copy bytes
@@ -517,8 +506,7 @@ dsp_io_ops(struct dsp_cdevpriv *priv, struct uio *buf)
 	ch->inprog--;
 
 	CHN_BROADCAST(&ch->cv);
-
-	dsp_unlock_chans(priv, prio);
+	CHN_UNLOCK(ch);
 
 	PCM_GIANT_LEAVE(d);