blob: 4eb04641376d1ea5a7eaa577e3ee3a722dbf08c1 [file] [log] [blame]
From 05845fa312df22c1f0e728f89c212ba7dedce1ae Mon Sep 17 00:00:00 2001
From: Peng Fan <peng.fan@nxp.com>
Date: Wed, 13 Nov 2019 05:37:42 +0000
Subject: [PATCH] tty: serial: pch_uart: correct usage of dma_unmap_sg
commit 74887542fdcc92ad06a48c0cca17cdf09fc8aa00 upstream.
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>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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++) {
--
2.7.4