mmc: pxamci: fix potential oops

As reported by Dan in his report in [1], there is a potential NULL
pointer derefence if these conditions are met :
 - there is no platform_data provided, ie. host->pdata = NULL

Fix this by only using the platform data ro_invert when a gpio for
read-only is provided by the platform data.

This doesn't appear yet as every pxa board provides a platform_data, and
calls pxa_set_mci_info() with a non NULL pointer.

[1] [bug report] mmc: pxamci: fix card detect with slot-gpio API.
The commit fd546ee6a7dc ("mmc: pxamci: fix card detect with slot-gpio
API") from Sep 26, 2015, leads to the following static checker warning:

	drivers/mmc/host/pxamci.c:809 pxamci_probe()
	warn: variable dereferenced before check 'host->pdata' (see line 798)

Fixes: fd546ee6a7dc ("mmc: pxamci: fix card detect with slot-gpio API")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/pxamci.c b/drivers/mmc/host/pxamci.c
index 86fac3e..c763b40 100644 (file)
--- a/drivers/mmc/host/pxamci.c
+++ b/drivers/mmc/host/pxamci.c
@@ -789,14 +789,16 @@ static int pxamci_probe(struct platform_device *pdev)
                gpio_direction_output(gpio_power,
                                      host->pdata->gpio_power_invert);
        }
-       if (gpio_is_valid(gpio_ro))
+       if (gpio_is_valid(gpio_ro)) {
                ret = mmc_gpio_request_ro(mmc, gpio_ro);
-       if (ret) {
-               dev_err(&pdev->dev, "Failed requesting gpio_ro %d\n", gpio_ro);
-               goto out;
-       } else {
-               mmc->caps2 |= host->pdata->gpio_card_ro_invert ?
-                       0 : MMC_CAP2_RO_ACTIVE_HIGH;
+               if (ret) {
+                       dev_err(&pdev->dev, "Failed requesting gpio_ro %d\n",
+                               gpio_ro);
+                       goto out;
+               } else {
+                       mmc->caps2 |= host->pdata->gpio_card_ro_invert ?
+                               0 : MMC_CAP2_RO_ACTIVE_HIGH;
+               }
        }
 
        if (gpio_is_valid(gpio_cd))