mtd: ichxrom: maybe-uninitialized with gcc-4.9

pci_read_config_word() might fail and not initialize its output,
as pointed out by older versions of gcc when using the -Wmaybe-unintialized
flag:

drivers/mtd/maps/ichxrom.c: In function ‘ichxrom_cleanup’:
drivers/mtd/maps/ichxrom.c:63:2: error: ‘word’ is used uninitialized in this function [-Werror=uninitialized]

This is apparently a correct warning, though it does not show up
with newer compilers. Changing the code to not attempt to write
back uninitialized data into PCI config space is a correct
fix for the problem and avoids the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/drivers/mtd/maps/ichxrom.c b/drivers/mtd/maps/ichxrom.c
index e17d02ae03f0966419a8e42b5192967a98883b39..976d42f63aef6b45bc5489c79dd5283de238454e 100644 (file)
--- a/drivers/mtd/maps/ichxrom.c
+++ b/drivers/mtd/maps/ichxrom.c
@@ -57,10 +57,12 @@ static void ichxrom_cleanup(struct ichxrom_window *window)
 {
        struct ichxrom_map_info *map, *scratch;
        u16 word;
+       int ret;
 
        /* Disable writes through the rom window */
-       pci_read_config_word(window->pdev, BIOS_CNTL, &word);
-       pci_write_config_word(window->pdev, BIOS_CNTL, word & ~1);
+       ret = pci_read_config_word(window->pdev, BIOS_CNTL, &word);
+       if (!ret)
+               pci_write_config_word(window->pdev, BIOS_CNTL, word & ~1);
        pci_dev_put(window->pdev);
 
        /* Free all of the mtd devices */