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From: "Kővágó, Zoltán" <dirty.ice.hu@gmail.com>
To: qemu-devel@nongnu.org
Cc: Gerd Hoffmann <kraxel@redhat.com>
Subject: [Qemu-devel] [PATCH 25/25] usbaudio: change playback counters to 64 bit
Date: Sun, 25 Aug 2019 20:46:27 +0200
Message-ID: <e977b11c8259297cd38ada4d564c9ec31b2e4b35.1566755452.git.DirtY.iCE.hu@gmail.com> (raw)
In-Reply-To: <cover.1566755452.git.DirtY.iCE.hu@gmail.com>

With stereo playback, they need about 375 minutes of continuous audio
playback to overflow, which is usually not a problem (as stopping and
later resuming playback resets the counters).  But with 7.1 audio, they
only need about 95 minutes to overflow.

After the overflow, the buf->prod % USBAUDIO_PACKET_SIZE(channels)
assertion no longer holds true, which will result in overflowing the
buffer.  With 64 bit variables, it would take about 762000 years to
overflow.

Signed-off-by: Kővágó, Zoltán <DirtY.iCE.hu@gmail.com>
---
 hw/usb/dev-audio.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/hw/usb/dev-audio.c b/hw/usb/dev-audio.c
index e42bdfbdc1..ea604bbb8e 100644
--- a/hw/usb/dev-audio.c
+++ b/hw/usb/dev-audio.c
@@ -578,9 +578,9 @@ static const USBDesc desc_audio_multi = {
 
 struct streambuf {
     uint8_t *data;
-    uint32_t size;
-    uint32_t prod;
-    uint32_t cons;
+    size_t size;
+    uint64_t prod;
+    uint64_t cons;
 };
 
 static void streambuf_init(struct streambuf *buf, uint32_t size,
@@ -601,7 +601,7 @@ static void streambuf_fini(struct streambuf *buf)
 
 static int streambuf_put(struct streambuf *buf, USBPacket *p, uint32_t channels)
 {
-    uint32_t free = buf->size - (buf->prod - buf->cons);
+    int64_t free = buf->size - (buf->prod - buf->cons);
 
     if (free < USBAUDIO_PACKET_SIZE(channels)) {
         return 0;
@@ -610,6 +610,8 @@ static int streambuf_put(struct streambuf *buf, USBPacket *p, uint32_t channels)
         return 0;
     }
 
+    /* can happen if prod overflows */
+    assert(buf->prod % USBAUDIO_PACKET_SIZE(channels) == 0);
     usb_packet_copy(p, buf->data + (buf->prod % buf->size),
                     USBAUDIO_PACKET_SIZE(channels));
     buf->prod += USBAUDIO_PACKET_SIZE(channels);
@@ -618,10 +620,10 @@ static int streambuf_put(struct streambuf *buf, USBPacket *p, uint32_t channels)
 
 static uint8_t *streambuf_get(struct streambuf *buf, size_t *len)
 {
-    uint32_t used = buf->prod - buf->cons;
+    int64_t used = buf->prod - buf->cons;
     uint8_t *data;
 
-    if (!used) {
+    if (used <= 0) {
         *len = 0;
         return NULL;
     }
-- 
2.22.0



      parent reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-25 18:46 [Qemu-devel] [PATCH 00/25] Audio: Mixeng-free 5.1/7.1 audio support Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 01/25] audio: api for mixeng code free backends Kővágó, Zoltán
2019-08-27  5:43   ` Gerd Hoffmann
2019-08-25 18:46 ` [Qemu-devel] [PATCH 02/25] alsaaudio: port to the new audio backend api Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 03/25] coreaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 04/25] dsoundaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 05/25] noaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 06/25] ossaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 07/25] paaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 08/25] sdlaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 10/25] wavaudio: " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 11/25] audio: remove remains of the old " Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 12/25] audio: unify input and output mixeng buffer management Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 13/25] audio: remove hw->samples, buffer_size_in/out pcm_ops Kővágó, Zoltán
2019-08-27  5:48   ` Gerd Hoffmann
2019-08-25 18:46 ` [Qemu-devel] [PATCH 14/25] audio: common rate control code for timer based outputs Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 15/25] audio: split ctl_* functions into enable_* and volume_* Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 16/25] audio: add mixeng option (documentation) Kővágó, Zoltán
2019-08-26 13:35   ` Eric Blake
2019-08-26 20:04     ` Zoltán Kővágó
2019-08-25 18:46 ` [Qemu-devel] [PATCH 17/25] audio: make mixeng optional Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 19/25] audio: support more than two channels in volume setting Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 20/25] audio: replace shift in audio_pcm_info with bytes_per_frame Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 21/25] audio: basic support for multichannel audio Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 22/25] paaudio: channel-map option Kővágó, Zoltán
2019-08-25 18:46 ` [Qemu-devel] [PATCH 23/25] usb-audio: do not count on avail bytes actually available Kővágó, Zoltán
2019-08-25 18:46 ` Kővágó, Zoltán [this message]

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