At Thu, 16 Apr 2009 19:35:01 +0200,
Karsten Wiese wrote:
>
> Within 2.6.30's mergewindow, struct urb's transfer_buffer_length has become
> unsigned. This changed an "int > int" comparision to an "unsigned > int" one
> in snd_usb_122l.
Does this cause any error, i.e. a real bug? Otherwise this patch isn't
needed for stable kernel.
The change itself looks OK to me, though.
thanks,
Takashi
> Fix this by using a local int variable instead of urb->transfer_buffer_length
> in comparisions.
>
> Shorten playback_prep_freqn() a bit and tweak error-paths in
> usb_stream_prepare_playback().
>
> Signed-off-by: Karsten Wiese <fzu@xxxxxxxxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxx
> ---
> sound/usb/usx2y/usb_stream.c | 67 +++++++++++++++++++-----------------------
> 1 files changed, 30 insertions(+), 37 deletions(-)
>
> diff --git a/sound/usb/usx2y/usb_stream.c b/sound/usb/usx2y/usb_stream.c
> index 24393da..12ae034 100644
> --- a/sound/usb/usx2y/usb_stream.c
> +++ b/sound/usb/usx2y/usb_stream.c
> @@ -33,32 +33,26 @@ static unsigned usb_stream_next_packet_size(struct usb_stream_kernel *sk)
> static void playback_prep_freqn(struct usb_stream_kernel *sk, struct urb *urb)
> {
> struct usb_stream *s = sk->s;
> - unsigned l = 0;
> - int pack;
> -
> - urb->iso_frame_desc[0].offset = 0;
> - urb->iso_frame_desc[0].length = usb_stream_next_packet_size(sk);
> - sk->out_phase = sk->out_phase_peeked;
> - urb->transfer_buffer_length = urb->iso_frame_desc[0].length;
> -
> - for (pack = 1; pack < sk->n_o_ps; pack++) {
> - l = usb_stream_next_packet_size(sk);
> - if (s->idle_outsize + urb->transfer_buffer_length + l >
> - s->period_size)
> + int pack, lb = 0;
> +
> + for (pack = 0; pack < sk->n_o_ps; pack++) {
> + int l = usb_stream_next_packet_size(sk);
> + if (s->idle_outsize + lb + l > s->period_size)
> goto check;
>
> sk->out_phase = sk->out_phase_peeked;
> - urb->iso_frame_desc[pack].offset = urb->transfer_buffer_length;
> + urb->iso_frame_desc[pack].offset = lb;
> urb->iso_frame_desc[pack].length = l;
> - urb->transfer_buffer_length += l;
> + lb += l;
> }
> - snd_printdd(KERN_DEBUG "%i\n", urb->transfer_buffer_length);
> + snd_printdd(KERN_DEBUG "%i\n", lb);
>
> check:
> urb->number_of_packets = pack;
> - s->idle_outsize += urb->transfer_buffer_length - s->period_size;
> + urb->transfer_buffer_length = lb;
> + s->idle_outsize += lb - s->period_size;
> snd_printdd(KERN_DEBUG "idle=%i ul=%i ps=%i\n", s->idle_outsize,
> - urb->transfer_buffer_length, s->period_size);
> + lb, s->period_size);
> }
>
> static void init_pipe_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
> @@ -282,21 +276,20 @@ static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
> struct usb_stream *s = sk->s;
> struct urb *io;
> struct usb_iso_packet_descriptor *id, *od;
> - int p, l = 0;
> + int p = 0, lb = 0, l = 0;
>
> io = sk->idle_outurb;
> od = io->iso_frame_desc;
> - io->transfer_buffer_length = 0;
>
> - for (p = 0; s->sync_packet < 0; ++p, ++s->sync_packet) {
> + for (; s->sync_packet < 0; ++p, ++s->sync_packet) {
> struct urb *ii = sk->completed_inurb;
> id = ii->iso_frame_desc +
> ii->number_of_packets + s->sync_packet;
> l = id->actual_length;
>
> od[p].length = l;
> - od[p].offset = io->transfer_buffer_length;
> - io->transfer_buffer_length += l;
> + od[p].offset = lb;
> + lb += l;
> }
>
> for (;
> @@ -304,38 +297,38 @@ static int usb_stream_prepare_playback(struct usb_stream_kernel *sk,
> ++p, ++s->sync_packet) {
> l = inurb->iso_frame_desc[s->sync_packet].actual_length;
>
> - if (s->idle_outsize + io->transfer_buffer_length + l >
> - s->period_size)
> + if (s->idle_outsize + lb + l > s->period_size)
> goto check_ok;
>
> od[p].length = l;
> - od[p].offset = io->transfer_buffer_length;
> - io->transfer_buffer_length += l;
> + od[p].offset = lb;
> + lb += l;
> }
>
> check_ok:
> s->sync_packet -= inurb->number_of_packets;
> - if (s->sync_packet < -2 || s->sync_packet > 0) {
> + if (unlikely(s->sync_packet < -2 || s->sync_packet > 0)) {
> snd_printk(KERN_WARNING "invalid sync_packet = %i;"
> " p=%i nop=%i %i %x %x %x > %x\n",
> s->sync_packet, p, inurb->number_of_packets,
> - s->idle_outsize + io->transfer_buffer_length + l,
> - s->idle_outsize, io->transfer_buffer_length, l,
> + s->idle_outsize + lb + l,
> + s->idle_outsize, lb, l,
> s->period_size);
> return -1;
> }
> - if (io->transfer_buffer_length % s->cfg.frame_size) {
> + if (unlikely(lb % s->cfg.frame_size)) {
> snd_printk(KERN_WARNING"invalid outsize = %i\n",
> - io->transfer_buffer_length);
> + lb);
> return -1;
> }
> - s->idle_outsize += io->transfer_buffer_length - s->period_size;
> + s->idle_outsize += lb - s->period_size;
> io->number_of_packets = p;
> - if (s->idle_outsize > 0) {
> - snd_printk(KERN_WARNING "idle=%i\n", s->idle_outsize);
> - return -1;
> - }
> - return 0;
> + io->transfer_buffer_length = lb;
> + if (s->idle_outsize <= 0)
> + return 0;
> +
> + snd_printk(KERN_WARNING "idle=%i\n", s->idle_outsize);
> + return -1;
> }
>
> static void prepare_inurb(int number_of_packets, struct urb *iu)
> --
> 1.6.0.6
>
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