From: ratchov <ratchov@openbsd.org>
Date: Tue, 12 May 2015 18:05:43 +0000 (+0000)
Subject: Don't hold the audio mutex when calling uiomove(), as uiomove()
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=4ac461ca809b04c4b1f9d4a1bebcb76cf480058f;p=openbsd

Don't hold the audio mutex when calling uiomove(), as uiomove()
may sleep in case of a page fault
---

diff --git a/sys/dev/midi.c b/sys/dev/midi.c
index d2f00461b66..277682a932e 100644
--- a/sys/dev/midi.c
+++ b/sys/dev/midi.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: midi.c,v 1.34 2015/03/14 03:38:46 jsg Exp $	*/
+/*	$OpenBSD: midi.c,v 1.35 2015/05/12 18:05:43 ratchov Exp $	*/
 
 /*
  * Copyright (c) 2003, 2004 Alexandre Ratchov
@@ -141,11 +141,11 @@ midiread(dev_t dev, struct uio *uio, int ioflag)
 			count = mb->used;
 		if (count > uio->uio_resid)
 			count = uio->uio_resid;
+		mtx_leave(&audio_lock);
 		error = uiomovei(mb->data + mb->start, count, uio);
-		if (error) {
-			mtx_leave(&audio_lock);
+		if (error)
 			return error;
-		}
+		mtx_enter(&audio_lock);
 		MIDIBUF_REMOVE(mb, count);
 	}
 	mtx_leave(&audio_lock);
@@ -246,12 +246,13 @@ midiwrite(dev_t dev, struct uio *uio, int ioflag)
 	 * in the buffer to store at least one byte. If not then dont
 	 * start the write process.
 	 */
-
-	if ((ioflag & IO_NDELAY) && MIDIBUF_ISFULL(mb) && (uio->uio_resid > 0))
+	mtx_enter(&audio_lock);
+	if ((ioflag & IO_NDELAY) && MIDIBUF_ISFULL(mb) && (uio->uio_resid > 0)) {
+		mtx_leave(&audio_lock);
 		return EWOULDBLOCK;
+	}
 
 	while (uio->uio_resid > 0) {
-		mtx_enter(&audio_lock);
 		while (MIDIBUF_ISFULL(mb)) {
 			if (ioflag & IO_NDELAY) {
 				/*
@@ -279,15 +280,15 @@ midiwrite(dev_t dev, struct uio *uio, int ioflag)
 			count = MIDIBUF_AVAIL(mb);
 		if (count > uio->uio_resid)
 			count = uio->uio_resid;
+		mtx_leave(&audio_lock);
 		error = uiomovei(mb->data + MIDIBUF_END(mb), count, uio);
-		if (error) {
-			mtx_leave(&audio_lock);
+		if (error)
 			return error;
-		}
+		mtx_enter(&audio_lock);
 		mb->used += count;
 		midi_out_start(sc);
-		mtx_leave(&audio_lock);
 	}
+	mtx_leave(&audio_lock);
 	return 0;
 }