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| author |   Peng Fan <peng.fan@nxp.com> | 2019-11-13 05:37:42 +0000 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-13 21:54:15 +0800 |
| commit | 74887542fdcc92ad06a48c0cca17cdf09fc8aa00 (patch) | |
| tree | 10227f52e3eec4716e44540ad8b1e7a3297f5028 /drivers/tty | |
| parent | tty: serial: imx: use the sg count from dma_map_sg (diff) | |
| download | linux-dev-74887542fdcc92ad06a48c0cca17cdf09fc8aa00.tar.xz linux-dev-74887542fdcc92ad06a48c0cca17cdf09fc8aa00.zip | |
tty: serial: pch_uart: correct usage of dma_unmap_sg
Per Documentation/DMA-API-HOWTO.txt,
To unmap a scatterlist, just call:
dma_unmap_sg(dev, sglist, nents, direction);
.. note::
The 'nents' argument to the dma_unmap_sg call must be
the _same_ one you passed into the dma_map_sg call,
it should _NOT_ be the 'count' value _returned_ from the
dma_map_sg call.
However in the driver, priv->nent is directly assigned with value
returned from dma_map_sg, and dma_unmap_sg use priv->nent for unmap,
this breaks the API usage.
So introduce a new entry orig_nent to remember 'nents'.
Fixes: da3564ee027e ("pch_uart: add multi-scatter processing")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Link: https://lore.kernel.org/r/1573623259-6339-1-git-send-email-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/pch_uart.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c index 6157213a8359..c16234bca78f 100644 --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -233,6 +233,7 @@ struct eg20t_port { struct dma_chan *chan_rx; struct scatterlist *sg_tx_p; int nent; + int orig_nent; struct scatterlist sg_rx; int tx_dma_use; void *rx_buf_virt; @@ -787,9 +788,10 @@ static void pch_dma_tx_complete(void *arg) } xmit->tail &= UART_XMIT_SIZE - 1; async_tx_ack(priv->desc_tx); - dma_unmap_sg(port->dev, sg, priv->nent, DMA_TO_DEVICE); + dma_unmap_sg(port->dev, sg, priv->orig_nent, DMA_TO_DEVICE); priv->tx_dma_use = 0; priv->nent = 0; + priv->orig_nent = 0; kfree(priv->sg_tx_p); pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_TX_INT); } @@ -1010,6 +1012,7 @@ static unsigned int dma_handle_tx(struct eg20t_port *priv) dev_err(priv->port.dev, "%s:dma_map_sg Failed\n", __func__); return 0; } + priv->orig_nent = num; priv->nent = nent; for (i = 0; i < nent; i++, sg++) { |