| Message ID | 1491200468-28463-1-git-send-email-m.szyprowski@samsung.com |
|---|---|
| State | Accepted |
| Commit | 768d64f491a530062ddad50e016fb27125f8bd7c |
| Headers | show |
| Series | [v3,1/3] serial: samsung: Use right device for DMA-mapping calls | expand |
On Mon, Apr 03, 2017 at 08:21:00AM +0200, Marek Szyprowski wrote: > 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) > [<c011aaa4>] (unwind_backtrace) from [<c01127c0>] (show_stack+0x20/0x24) > [<c01127c0>] (show_stack) from [<c06ba5d8>] (dump_stack+0x84/0xa0) > [<c06ba5d8>] (dump_stack) from [<c0139528>] (__warn+0x14c/0x180) > [<c0139528>] (__warn) from [<c01395a4>] (warn_slowpath_fmt+0x48/0x50) > [<c01395a4>] (warn_slowpath_fmt) from [<c072a114>] (check_unmap+0x8a0/0xf28) > [<c072a114>] (check_unmap) from [<c072a834>] (debug_dma_unmap_page+0x98/0xc8) > [<c072a834>] (debug_dma_unmap_page) from [<c0803874>] (s3c24xx_serial_shutdown+0x314/0x52c) > [<c0803874>] (s3c24xx_serial_shutdown) from [<c07f5124>] (uart_port_shutdown+0x54/0x88) > [<c07f5124>] (uart_port_shutdown) from [<c07f522c>] (uart_shutdown+0xd4/0x110) > [<c07f522c>] (uart_shutdown) from [<c07f6a8c>] (uart_hangup+0x9c/0x208) > [<c07f6a8c>] (uart_hangup) from [<c07c426c>] (__tty_hangup+0x49c/0x634) > [<c07c426c>] (__tty_hangup) from [<c07c78ac>] (tty_ioctl+0xc88/0x16e4) > [<c07c78ac>] (tty_ioctl) from [<c03b5f2c>] (do_vfs_ioctl+0xc4/0xd10) > [<c03b5f2c>] (do_vfs_ioctl) from [<c03b6bf4>] (SyS_ioctl+0x7c/0x8c) > [<c03b6bf4>] (SyS_ioctl) from [<c010b4a0>] (ret_fast_syscall+0x0/0x3c) > > Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com> > Fixes: 62c37eedb74c8 ("serial: samsung: add dma reqest/release functions") > CC: stable@vger.kernel.org # v4.10+ > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> > --- > This issue was there since adding DMA support, but this patch applies cleanly > only to v4.10+ kernels due to other changes in the surrounding code. > > v3: > - moved spinlock removal to separate patch, extended commit message Thanks for the changes, looks fine. Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Best regards, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Apr 03, 2017 at 08:21:01AM +0200, Marek Szyprowski wrote: > Spinlock taken only for dma_map_single() for TX buffer is completely > useless and doesn't protect anything, so remove it to simplify the code. > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > --- > drivers/tty/serial/samsung.c | 4 ---- > 1 file changed, 4 deletions(-) > Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Best regards, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index 7a17aedbf902..9f3759bdb44f 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -901,14 +901,13 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) return -ENOMEM; } - dma->rx_addr = dma_map_single(dma->rx_chan->device->dev, dma->rx_buf, + dma->rx_addr = dma_map_single(p->port.dev, dma->rx_buf, dma->rx_size, DMA_FROM_DEVICE); spin_lock_irqsave(&p->port.lock, flags); /* TX buffer */ - dma->tx_addr = dma_map_single(dma->tx_chan->device->dev, - p->port.state->xmit.buf, + dma->tx_addr = dma_map_single(p->port.dev, p->port.state->xmit.buf, UART_XMIT_SIZE, DMA_TO_DEVICE); spin_unlock_irqrestore(&p->port.lock, flags); @@ -922,7 +921,7 @@ static void s3c24xx_serial_release_dma(struct s3c24xx_uart_port *p) if (dma->rx_chan) { dmaengine_terminate_all(dma->rx_chan); - dma_unmap_single(dma->rx_chan->device->dev, dma->rx_addr, + dma_unmap_single(p->port.dev, dma->rx_addr, dma->rx_size, DMA_FROM_DEVICE); kfree(dma->rx_buf); dma_release_channel(dma->rx_chan); @@ -931,7 +930,7 @@ static void s3c24xx_serial_release_dma(struct s3c24xx_uart_port *p) if (dma->tx_chan) { dmaengine_terminate_all(dma->tx_chan); - dma_unmap_single(dma->tx_chan->device->dev, dma->tx_addr, + dma_unmap_single(p->port.dev, dma->tx_addr, UART_XMIT_SIZE, DMA_TO_DEVICE); dma_release_channel(dma->tx_chan); dma->tx_chan = NULL;
Driver should provide its own struct device for all DMA-mapping calls instead of extracting device pointer from DMA engine channel. Although this is harmless from the driver operation perspective on ARM architecture, it is always good to use the DMA mapping API in a proper way. This patch fixes following DMA API debug warning: WARNING: CPU: 0 PID: 0 at lib/dma-debug.c:1241 check_sync+0x520/0x9f4 samsung-uart 12c20000.serial: DMA-API: device driver tries to sync DMA memory it has not allocated [device address=0x000000006df0f580] [size=64 bytes] Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.11.0-rc1-00137-g07ca963 #51 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [<c011aaa4>] (unwind_backtrace) from [<c01127c0>] (show_stack+0x20/0x24) [<c01127c0>] (show_stack) from [<c06ba5d8>] (dump_stack+0x84/0xa0) [<c06ba5d8>] (dump_stack) from [<c0139528>] (__warn+0x14c/0x180) [<c0139528>] (__warn) from [<c01395a4>] (warn_slowpath_fmt+0x48/0x50) [<c01395a4>] (warn_slowpath_fmt) from [<c0729058>] (check_sync+0x520/0x9f4) [<c0729058>] (check_sync) from [<c072967c>] (debug_dma_sync_single_for_device+0x88/0xc8) [<c072967c>] (debug_dma_sync_single_for_device) from [<c0803c10>] (s3c24xx_serial_start_tx_dma+0x100/0x2f8) [<c0803c10>] (s3c24xx_serial_start_tx_dma) from [<c0804338>] (s3c24xx_serial_tx_chars+0x198/0x33c) Reported-by: Seung-Woo Kim <sw0312.kim@samsung.com> Fixes: 62c37eedb74c8 ("serial: samsung: add dma reqest/release functions") CC: stable@vger.kernel.org # v4.0+ Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> --- v3: - extended commit message v2: - fixed commit id in 'fixes' tag, added 'reviewed-by' tag --- drivers/tty/serial/samsung.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html