From: Andy Shevchenko Date: Mon, 7 Mar 2022 17:37:40 +0000 (+0200) Subject: spi: topcliff-pch: Prevent usage of potentially stale DMA device X-Git-Tag: v6.6.17~7985^2~12 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=80ab9012bbf1011f57c06b3c6e4ac3816c4a86f5;p=platform%2Fkernel%2Flinux-rpi.git spi: topcliff-pch: Prevent usage of potentially stale DMA device DMA device is expected to be available while SPI transfer is ongoing. Prevent usage of potentially stale DMA device by keeping reference count till the end of the transfer. Fixes: 4d986ffa036a ("spi: add missing pci_dev_put() before return") Reported-by: Christophe JAILLET Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20220307173740.80996-1-andriy.shevchenko@linux.intel.com Signed-off-by: Mark Brown --- diff --git a/drivers/spi/spi-topcliff-pch.c b/drivers/spi/spi-topcliff-pch.c index 8e1cc34..dfaa1d7 100644 --- a/drivers/spi/spi-topcliff-pch.c +++ b/drivers/spi/spi-topcliff-pch.c @@ -103,6 +103,7 @@ static int use_dma = 1; struct pch_spi_dma_ctrl { + struct pci_dev *dma_dev; struct dma_async_tx_descriptor *desc_tx; struct dma_async_tx_descriptor *desc_rx; struct pch_dma_slave param_tx; @@ -876,7 +877,6 @@ static void pch_spi_request_dma(struct pch_spi_data *data, int bpw) if (!chan) { dev_err(&data->master->dev, "ERROR: dma_request_channel FAILS(Tx)\n"); - data->use_dma = 0; goto out; } dma->chan_tx = chan; @@ -893,13 +893,15 @@ static void pch_spi_request_dma(struct pch_spi_data *data, int bpw) "ERROR: dma_request_channel FAILS(Rx)\n"); dma_release_channel(dma->chan_tx); dma->chan_tx = NULL; - data->use_dma = 0; goto out; } dma->chan_rx = chan; + dma->dma_dev = dma_dev; + return; out: pci_dev_put(dma_dev); + data->use_dma = 0; } static void pch_spi_release_dma(struct pch_spi_data *data) @@ -915,6 +917,8 @@ static void pch_spi_release_dma(struct pch_spi_data *data) dma_release_channel(dma->chan_rx); dma->chan_rx = NULL; } + + pci_dev_put(dma->dma_dev); } static void pch_spi_handle_dma(struct pch_spi_data *data, int *bpw)