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serial: msm: check dma_map_sg() return value properly

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The -next commit f8fef2fa419f (tty: msm_serial: use
dmaengine_prep_slave_sg()), switched to using dma_map_sg(). But the
return value of dma_map_sg() is special: it returns number of elements
mapped. And not a standard error value.

The commit also forgot to reset dma->tx_sg in case of this failure.

Fix both these mistakes.

Thanks to Marek who helped debugging this.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20240419080931.30949-1-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Slaby (SUSE) 2024-04-19 10:09:31 +02:00 committed by Greg Kroah-Hartman
parent c6795fbffc
commit f70f95b485
1 changed files with 7 additions and 3 deletions
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10
drivers/tty/serial/msm_serial.c
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@ -499,15 +499,18 @@ static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
struct uart_port *port = &msm_port->uart; struct uart_port *port = &msm_port->uart;
struct tty_port *tport = &port->state->port; struct tty_port *tport = &port->state->port;
struct msm_dma *dma = &msm_port->tx_dma; struct msm_dma *dma = &msm_port->tx_dma;
unsigned int mapped;
int ret; int ret;
u32 val; u32 val;
sg_init_table(&dma->tx_sg, 1); sg_init_table(&dma->tx_sg, 1);
kfifo_dma_out_prepare(&tport->xmit_fifo, &dma->tx_sg, 1, count); kfifo_dma_out_prepare(&tport->xmit_fifo, &dma->tx_sg, 1, count);
ret = dma_map_sg(port->dev, &dma->tx_sg, 1, dma->dir); mapped = dma_map_sg(port->dev, &dma->tx_sg, 1, dma->dir);
if (ret) if (!mapped) {
return ret; ret = -EIO;
goto zero_sg;
}
dma->desc = dmaengine_prep_slave_sg(dma->chan, &dma->tx_sg, 1, dma->desc = dmaengine_prep_slave_sg(dma->chan, &dma->tx_sg, 1,
DMA_MEM_TO_DEV, DMA_MEM_TO_DEV,
@ -548,6 +551,7 @@ static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count)
return 0; return 0;
unmap: unmap:
dma_unmap_sg(port->dev, &dma->tx_sg, 1, dma->dir); dma_unmap_sg(port->dev, &dma->tx_sg, 1, dma->dir);
zero_sg:
sg_init_table(&dma->tx_sg, 1); sg_init_table(&dma->tx_sg, 1);
return ret; return ret;
} }