mtd: ichxrom: maybe-uninitialized with gcc-4.9

commit e70dda0868fad0f74c46df21f7f45fec24f29879 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mtd/maps/ichxrom.c b/drivers/mtd/maps/ichxrom.c
index 8636bba422009a1f54ff58b1611acac54cbf9b45..6668c06140f29c91cc58ffd2120f682e97374878 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 */