Re: [PATCH v15 2/4] dmaengine: tegra: Add tegra gpcdma driver

Dmitry Osipenko
2021-12-16T17:42:32Z

16.12.2021 20:11, Akhil R пишет:
> +static int tegra_dma_terminate_all(struct dma_chan *dc)
> +{
> + struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc);
> + unsigned long wcount = 0;
> + unsigned long status;
> + unsigned long flags;
> + int err;
> +
> + raw_spin_lock_irqsave(&tdc->lock, flags);
> +
> + if (!tdc->dma_desc) {
> + raw_spin_unlock_irqrestore(&tdc->lock, flags);
> + return 0;
> + }
> +
> + if (!tdc->busy)
> + goto skip_dma_stop;
> +
> + if (tdc->tdma->chip_data->hw_support_pause)
> + err = tegra_dma_pause(tdc);
> + else
> + err = tegra_dma_stop_client(tdc);
> +
> + if (err) {
> + raw_spin_unlock_irqrestore(&tdc->lock, flags);
> + return err;
> + }
> +
> + status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS);
> + if (status & TEGRA_GPCDMA_STATUS_ISE_EOC) {
> + dev_dbg(tdc2dev(tdc), "%s():handling isr\n", __func__);
> + tegra_dma_xfer_complete(tdc);
> + status = tdc_read(tdc, TEGRA_GPCDMA_CHAN_STATUS);
> + }
> +
> + wcount = tdc_read(tdc, TEGRA_GPCDMA_CHAN_XFER_COUNT);
> + tegra_dma_stop(tdc);
> +
> + tdc->dma_desc->bytes_transferred +=
> + tdc->dma_desc->bytes_requested - (wcount * 4);
> +
> +skip_dma_stop:
> + tegra_dma_sid_free(tdc);
> + vchan_free_chan_resources(&tdc->vc);
> + kfree(&tdc->vc);

You really going to kfree the head of tegra_dma_channel here? Once
again, this code was 100% untested :/

You're not allowed to free channel from the dma_terminate_all()
callback. This callback terminates submitted descs, that's it.