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spi: sh-msiof: Fix leaking of unused DMA descriptors 

If dmaengine_prep_slave_sg() or dmaengine_submit() fail, we may leak
unused DMA descriptors.

As per Documentation/dmaengine.txt, once a DMA descriptor has been
obtained, it must be submitted. Hence:
  - First prepare and submit all DMA descriptors,
  - Prepare the SPI controller for DMA,
  - Start DMA by calling dma_async_issue_pending(),
  - Make sure to call dmaengine_terminate_all() on all descriptors that
    haven't completed.

Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
Geert Uytterhoeven 2014-08-06 14:59:03 +02:00 committed by Mark Brown
parent 7d1311b93e
commit 3e81b59208
1 changed files with 43 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
drivers/spi/spi-sh-msiof.c
View File

@ -636,6 +636,26 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx,
dma_cookie_t cookie;
int ret;
/* First prepare and submit the DMA request(s), as this may fail */
if (rx) {
ier_bits |= IER_RDREQE | IER_RDMAE;
desc_rx = dmaengine_prep_slave_single(p->master->dma_rx,
p->rx_dma_addr, len, DMA_FROM_DEVICE,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc_rx) {
ret = -EAGAIN;
goto no_dma_rx;
}
desc_rx->callback = sh_msiof_dma_complete;
desc_rx->callback_param = p;
cookie = dmaengine_submit(desc_rx);
if (dma_submit_error(cookie)) {
ret = cookie;
goto no_dma_rx;
}
}
if (tx) {
ier_bits |= IER_TDREQE | IER_TDMAE;
dma_sync_single_for_device(p->master->dma_tx->device->dev,
@ -643,17 +663,23 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx,
desc_tx = dmaengine_prep_slave_single(p->master->dma_tx,
p->tx_dma_addr, len, DMA_TO_DEVICE,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc_tx)
return -EAGAIN;
if (!desc_tx) {
ret = -EAGAIN;
goto no_dma_tx;
}
if (rx) {
ier_bits |= IER_RDREQE | IER_RDMAE;
desc_rx = dmaengine_prep_slave_single(p->master->dma_rx,
p->rx_dma_addr, len, DMA_FROM_DEVICE,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc_rx)
return -EAGAIN;
/* No callback */
desc_tx->callback = NULL;
} else {
desc_tx->callback = sh_msiof_dma_complete;
desc_tx->callback_param = p;
}
cookie = dmaengine_submit(desc_tx);
if (dma_submit_error(cookie)) {
ret = cookie;
goto no_dma_tx;
}
}
/* 1 stage FIFO watermarks for DMA */
@ -666,37 +692,16 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx,
reinit_completion(&p->done);
if (rx) {
desc_rx->callback = sh_msiof_dma_complete;
desc_rx->callback_param = p;
cookie = dmaengine_submit(desc_rx);
if (dma_submit_error(cookie)) {
ret = cookie;
goto stop_ier;
}
/* Now start DMA */
if (tx)
dma_async_issue_pending(p->master->dma_rx);
}
if (tx) {
if (rx) {
/* No callback */
desc_tx->callback = NULL;
} else {
desc_tx->callback = sh_msiof_dma_complete;
desc_tx->callback_param = p;
}
cookie = dmaengine_submit(desc_tx);
if (dma_submit_error(cookie)) {
ret = cookie;
goto stop_rx;
}
if (rx)
dma_async_issue_pending(p->master->dma_tx);
}
ret = sh_msiof_spi_start(p, rx);
if (ret) {
dev_err(&p->pdev->dev, "failed to start hardware\n");
goto stop_tx;
goto stop_dma;
}
/* wait for tx fifo to be emptied / rx fifo to be filled */
@ -726,14 +731,14 @@ static int sh_msiof_dma_once(struct sh_msiof_spi_priv *p, const void *tx,
stop_reset:
sh_msiof_reset_str(p);
sh_msiof_spi_stop(p, rx);
stop_tx:
stop_dma:
if (tx)
dmaengine_terminate_all(p->master->dma_tx);
stop_rx:
no_dma_tx:
if (rx)
dmaengine_terminate_all(p->master->dma_rx);
stop_ier:
sh_msiof_write(p, IER, 0);
no_dma_rx:
return ret;
}