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Message-Id: <20200116173641.22137-201-sashal@kernel.org>
Date: Thu, 16 Jan 2020 12:36:30 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc: Peng Fan <peng.fan@....com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Sasha Levin <sashal@...nel.org>, linux-serial@...r.kernel.org
Subject: [PATCH AUTOSEL 4.9 241/251] tty: serial: pch_uart: correct usage of dma_unmap_sg
From: Peng Fan <peng.fan@....com>
[ Upstream commit 74887542fdcc92ad06a48c0cca17cdf09fc8aa00 ]
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@....com>
Link: https://lore.kernel.org/r/1573623259-6339-1-git-send-email-peng.fan@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
drivers/tty/serial/pch_uart.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 42caccb5e87e..30b577384a1d 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -252,6 +252,7 @@ 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;
@@ -806,9 +807,10 @@ 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);
}
@@ -1033,6 +1035,7 @@ 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++) {
--
2.20.1
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