[PATCH v6] tty: 8250: fix a missing check for pci_ioremap_bar

[Aditya Pakki]

pci_ioremap_bar could fail. The patch returns in case of failure to
acquire IOMEM. It also releases the acquired resource in the exit path.

Signed-off-by: Aditya Pakki <pakki...@umn.edu>

---
v5: change pci_iounmap to iounmap to pass kbuild errors in other arch
v4: Missed resource release in dma_probe failure.
v3: Change the order of pci_iounmap and dw_dma_remove
v2: Failed to release resource in exit path and incorrect code in non
DMA case, suggested by Andy Shevchenko
v1: Missed return by default in CONFIG_SERIAL_8250_DMA, suggested by
Jiri Slaby
---
 drivers/tty/serial/8250/8250_lpss.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_lpss.c 
b/drivers/tty/serial/8250/8250_lpss.c
index 53ca9ba6ab4b..c7c7bf5d7e5e 100644
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -170,14 +170,18 @@ static void qrk_serial_setup_dma(struct lpss8250 *lpss, 
struct uart_port *port)
        int ret;
 
        chip->dev = &pdev->dev;
+       chip->pdata = &qrk_serial_dma_pdata;
        chip->irq = pci_irq_vector(pdev, 0);
        chip->regs = pci_ioremap_bar(pdev, 1);
-       chip->pdata = &qrk_serial_dma_pdata;
+       if (!chip->regs)
+               return;
 
        /* Falling back to PIO mode if DMA probing fails */
        ret = dw_dma_probe(chip);
-       if (ret)
+       if (ret) {
+               iounmap(chip->regs);
                return;
+       }
 
        pci_try_set_mwi(pdev);
 
@@ -199,7 +203,10 @@ static void qrk_serial_exit_dma(struct lpss8250 *lpss)
 
        if (!param->dma_dev)
                return;
+
        dw_dma_remove(&lpss->dma_chip);
+
+       iounmap(&lpss->dma_chip->regs);
 }
 #else  /* CONFIG_SERIAL_8250_DMA */
 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port 
*port) {}
-- 
2.17.1