From 500fcc08a32bfd54f11951ba81530775df15c474 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Mon, 3 Apr 2017 08:21:00 +0200 Subject: [PATCH] serial: samsung: Add missing checks for dma_map_single failure This patch adds missing checks for dma_map_single() failure and proper error reporting. Although this issue was harmless on ARM architecture, it is always good to use the DMA mapping API in a proper way. This patch fixes the following DMA API debug warning: WARNING: CPU: 1 PID: 3785 at lib/dma-debug.c:1171 check_unmap+0x8a0/0xf28 dma-pl330 121a0000.pdma: DMA-API: device driver failed to check map error[device address=0x000000006e0f9000] [size=4096 bytes] [mapped as single] Modules linked in: CPU: 1 PID: 3785 Comm: (agetty) Tainted: G W 4.11.0-rc1-00137-g07ca963-dirty #59 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [] (unwind_backtrace) from [] (show_stack+0x20/0x24) [] (show_stack) from [] (dump_stack+0x84/0xa0) [] (dump_stack) from [] (__warn+0x14c/0x180) [] (__warn) from [] (warn_slowpath_fmt+0x48/0x50) [] (warn_slowpath_fmt) from [] (check_unmap+0x8a0/0xf28) [] (check_unmap) from [] (debug_dma_unmap_page+0x98/0xc8) [] (debug_dma_unmap_page) from [] (s3c24xx_serial_shutdown+0x314/0x52c) [] (s3c24xx_serial_shutdown) from [] (uart_port_shutdown+0x54/0x88) [] (uart_port_shutdown) from [] (uart_shutdown+0xd4/0x110) [] (uart_shutdown) from [] (uart_hangup+0x9c/0x208) [] (uart_hangup) from [] (__tty_hangup+0x49c/0x634) [] (__tty_hangup) from [] (tty_ioctl+0xc88/0x16e4) [] (tty_ioctl) from [] (do_vfs_ioctl+0xc4/0xd10) [] (do_vfs_ioctl) from [] (SyS_ioctl+0x7c/0x8c) [] (SyS_ioctl) from [] (ret_fast_syscall+0x0/0x3c) Reported-by: Seung-Woo Kim Fixes: 62c37eedb74c8 ("serial: samsung: add dma reqest/release functions") CC: stable@vger.kernel.org # v4.10+ Signed-off-by: Marek Szyprowski Reviewed-by: Bartlomiej Zolnierkiewicz Reviewed-by: Shuah Khan Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/samsung.c | 31 ++++++++++++++++++++++++------- 1 file changed, 24 insertions(+), 7 deletions(-) diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index 9f3759bdb44fbc..ca0bcd7fd61f15 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -859,7 +859,7 @@ static void s3c24xx_serial_break_ctl(struct uart_port *port, int break_state) static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) { struct s3c24xx_uart_dma *dma = p->dma; - unsigned long flags; + int ret; /* Default slave configuration parameters */ dma->rx_conf.direction = DMA_DEV_TO_MEM; @@ -884,8 +884,8 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) dma->tx_chan = dma_request_chan(p->port.dev, "tx"); if (IS_ERR(dma->tx_chan)) { - dma_release_channel(dma->rx_chan); - return PTR_ERR(dma->tx_chan); + ret = PTR_ERR(dma->tx_chan); + goto err_release_rx; } dmaengine_slave_config(dma->tx_chan, &dma->tx_conf); @@ -894,15 +894,17 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) dma->rx_size = PAGE_SIZE; dma->rx_buf = kmalloc(dma->rx_size, GFP_KERNEL); - if (!dma->rx_buf) { - dma_release_channel(dma->rx_chan); - dma_release_channel(dma->tx_chan); - return -ENOMEM; + ret = -ENOMEM; + goto err_release_tx; } dma->rx_addr = dma_map_single(p->port.dev, dma->rx_buf, dma->rx_size, DMA_FROM_DEVICE); + if (dma_mapping_error(p->port.dev, dma->rx_addr)) { + ret = -EIO; + goto err_free_rx; + } spin_lock_irqsave(&p->port.lock, flags); @@ -911,8 +913,23 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) UART_XMIT_SIZE, DMA_TO_DEVICE); spin_unlock_irqrestore(&p->port.lock, flags); + if (dma_mapping_error(p->port.dev, dma->tx_addr)) { + ret = -EIO; + goto err_unmap_rx; + } return 0; + +err_unmap_rx: + dma_unmap_single(p->port.dev, dma->rx_addr, dma->rx_size, + DMA_FROM_DEVICE); +err_free_rx: + kfree(dma->rx_buf); +err_release_tx: + dma_release_channel(dma->tx_chan); +err_release_rx: + dma_release_channel(dma->rx_chan); + return ret; } static void s3c24xx_serial_release_dma(struct s3c24xx_uart_port *p)