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usbaudio: change playback counters to 64 bit

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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>
Message-id: ff866985ed369f1e18ea7c70da6a7fce8e241deb.1570996490.git.DirtY.iCE.hu@gmail.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Kővágó, Zoltán 2019-10-13 21:58:06 +02:00 committed by Gerd Hoffmann
parent 3e44607e93
commit 670777a915
1 changed files with 8 additions and 6 deletions

14
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;
}