Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1214129

Re: [PATCH 05/10] ALSA: axd: add buffers manipulation files

Show all headers | View raw

[Multipart message — attachments visible in raw view] - view raw

On Mon, Aug 24, 2015 at 01:39:14PM +0100, Qais Yousef wrote:

> +	/*
> +	 * must ensure we have one access at a time to the queue and rd_idx
> +	 * to be preemption and SMP safe
> +	 * Sempahores will ensure that we will only read after a complete write
> +	 * has finished, so we will never read and write from the same location.
> +	 */

In what way will sempahores ensure that we will only read after a
complete write?

> +	buf = bufferq->queue[bufferq->rd_idx];

So buffers are always retired in the same order that they are acquired?

> +int axd_bufferq_put(struct axd_bufferq *bufferq, char *buf, int buf_size)
> +{
> +	int ret;
> +
> +	if (!bufferq->queue)
> +		return 0;
> +
> +	if (buf_size < 0)
> +		buf_size = bufferq->stride;

We've got strides as well?  What is that?

> +void axd_bufferq_abort_take(struct axd_bufferq *bufferq)
> +{
> +	if (axd_bufferq_is_empty(bufferq)) {
> +		bufferq->abort_take = 1;
> +		up(&bufferq->rd_sem);
> +	}
> +}
> +
> +void axd_bufferq_abort_put(struct axd_bufferq *bufferq)
> +{
> +	if (axd_bufferq_is_full(bufferq)) {
> +		bufferq->abort_put = 1;
> +		up(&bufferq->wr_sem);
> +	}
> +}

These look *incredibly* racy.  Why are they here and why are they safe?

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 00/10] Add support for img AXD audio hardware decoder Qais Yousef <qais.yousef@imgtec.com> - 2015-08-24 14:40 +0200
  [PATCH 04/10] ALSA: axd: add fw binary header manipulation files Qais Yousef <qais.yousef@imgtec.com> - 2015-08-24 14:40 +0200
  [PATCH 09/10] ALSA: axd: add alsa compress offload operations Qais Yousef <qais.yousef@imgtec.com> - 2015-08-24 14:50 +0200
  [PATCH 05/10] ALSA: axd: add buffers manipulation files Qais Yousef <qais.yousef@imgtec.com> - 2015-08-24 14:50 +0200
    Re: [PATCH 05/10] ALSA: axd: add buffers manipulation files Mark Brown <broonie@kernel.org> - 2015-08-26 20:50 +0200
      Re: [PATCH 05/10] ALSA: axd: add buffers manipulation files Qais Yousef <qais.yousef@imgtec.com> - 2015-08-27 16:30 +0200
        Re: [PATCH 05/10] ALSA: axd: add buffers manipulation files Mark Brown <broonie@kernel.org> - 2015-08-29 11:50 +0200
          Re: [PATCH 05/10] ALSA: axd: add buffers manipulation files Qais Yousef <qais.yousef@imgtec.com> - 2015-09-01 12:10 +0200
            Re: [PATCH 05/10] ALSA: axd: add buffers manipulation files Mark Brown <broonie@kernel.org> - 2015-09-03 14:40 +0200
  [PATCH 08/10] ALSA: axd: add low level AXD platform setup files Qais Yousef <qais.yousef@imgtec.com> - 2015-08-24 14:50 +0200
  [PATCH 10/10] ALSA: axd: add Makefile Qais Yousef <qais.yousef@imgtec.com> - 2015-08-24 14:50 +0200
  Re: [PATCH 00/10] Add support for img AXD audio hardware decoder Mark Brown <broonie@kernel.org> - 2015-08-26 20:10 +0200
    Re: [PATCH 00/10] Add support for img AXD audio hardware decoder Qais Yousef <qais.yousef@imgtec.com> - 2015-08-27 11:10 +0200
  Re: [PATCH 03/10] ALSA: add AXD Audio Processing IP alsa driver Mark Brown <broonie@kernel.org> - 2015-08-26 20:40 +0200
    Re: [PATCH 03/10] ALSA: add AXD Audio Processing IP alsa driver Qais Yousef <qais.yousef@imgtec.com> - 2015-08-27 14:20 +0200
      Re: [PATCH 03/10] ALSA: add AXD Audio Processing IP alsa driver Mark Brown <broonie@kernel.org> - 2015-08-27 17:40 +0200
        Re: [PATCH 03/10] ALSA: add AXD Audio Processing IP alsa driver Qais Yousef <qais.yousef@imgtec.com> - 2015-08-28 11:30 +0200
          Re: [PATCH 03/10] ALSA: add AXD Audio Processing IP alsa driver Mark Brown <broonie@kernel.org> - 2015-09-03 14:50 +0200
  Re: [PATCH 06/10] ALSA: axd: add basic files for sending/receiving  axd cmds Mark Brown <broonie@kernel.org> - 2015-08-26 21:20 +0200
    Re: [PATCH 06/10] ALSA: axd: add basic files for sending/receiving  axd cmds Qais Yousef <qais.yousef@imgtec.com> - 2015-08-27 17:50 +0200
      Re: [PATCH 06/10] ALSA: axd: add basic files for sending/receiving  axd cmds Mark Brown <broonie@kernel.org> - 2015-08-29 12:20 +0200
        Re: [PATCH 06/10] ALSA: axd: add basic files for sending/receiving  axd cmds Qais Yousef <qais.yousef@imgtec.com> - 2015-09-01 12:50 +0200
          Re: [PATCH 06/10] ALSA: axd: add basic files for sending/receiving  axd cmds Mark Brown <broonie@kernel.org> - 2015-09-03 14:50 +0200

csiph-web