From f70f95b485d78838ad28dbec804b986d11ad7bb0 Mon Sep 17 00:00:00 2001 From: "Jiri Slaby (SUSE)" Date: Fri, 19 Apr 2024 10:09:31 +0200 Subject: [PATCH] serial: msm: check dma_map_sg() return value properly 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) Reported-by: Marek Szyprowski Tested-by: Marek Szyprowski Link: https://lore.kernel.org/r/20240419080931.30949-1-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/msm_serial.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index ae7a8e3cf467..0a9c5219df88 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -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 tty_port *tport = &port->state->port; struct msm_dma *dma = &msm_port->tx_dma; + unsigned int mapped; int ret; u32 val; sg_init_table(&dma->tx_sg, 1); kfifo_dma_out_prepare(&tport->xmit_fifo, &dma->tx_sg, 1, count); - ret = dma_map_sg(port->dev, &dma->tx_sg, 1, dma->dir); - if (ret) - return ret; + mapped = dma_map_sg(port->dev, &dma->tx_sg, 1, dma->dir); + if (!mapped) { + ret = -EIO; + goto zero_sg; + } dma->desc = dmaengine_prep_slave_sg(dma->chan, &dma->tx_sg, 1, DMA_MEM_TO_DEV, @@ -548,6 +551,7 @@ static int msm_handle_tx_dma(struct msm_port *msm_port, unsigned int count) return 0; unmap: dma_unmap_sg(port->dev, &dma->tx_sg, 1, dma->dir); +zero_sg: sg_init_table(&dma->tx_sg, 1); return ret; }