ipq806x: request the first free loop device dynamically for the nbg6817 sysupgrade

Instead of hardcoding /dev/loop0, it's safer to query for the first
free loop device and assign that dynamically. While /dev/loop0 is a
reasonable assumption immediately following "losetup --detach-all",
detaching the mounted overlay is no longer strictly necessary once
dual-boot support has been added for the nbg6817.

Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>

diff --git a/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh b/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh
index dcd66ea2caba5d94421984dcc07dc91952369764..cf2acfcc174d5d08e9a50f9e5fca63a19d7fcb9b 100644 (file)
--- a/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh
+++ b/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh
@@ -47,23 +47,24 @@ zyxel_do_flash() {
        }
 
        # Mount loop for rootfs_data
-       losetup -o $offset /dev/loop0 "${rootfs}" || {
+       local loopdev="$(losetup -f)"
+       losetup -o $offset $loopdev $rootfs || {
                echo "Failed to mount looped rootfs_data."
                sleep 10
                reboot -f
        }
 
        echo "Format new rootfs_data at position ${offset}."
-       mkfs.ext4 -F -L rootfs_data /dev/loop0
+       mkfs.ext4 -F -L rootfs_data $loopdev
        mkdir /tmp/new_root
-       mount -t ext4 /dev/loop0 /tmp/new_root && {
+       mount -t ext4 $loopdev /tmp/new_root && {
                echo "Saving config to rootfs_data at position ${offset}."
                cp -v /tmp/sysupgrade.tgz /tmp/new_root/
                umount /tmp/new_root
        }
 
        # Cleanup
-       losetup -d /dev/loop0 >/dev/null 2>&1
+       losetup -d $loopdev >/dev/null 2>&1
        sync
        umount -a
        reboot -f