Smatch complains that:
fs/erofs/zdata.c:1047 z_erofs_scan_folio()
error: uninitialized symbol 'err'.
The issue is if we hit this (!(map->m_flags & EROFS_MAP_MAPPED)) {
condition then "err" isn't set. It's inside a loop so we would have to
hit that condition on every iteration. Initialize "err" to zero to
solve this.
Fixes: 5b9654efb6 ("erofs: teach z_erofs_scan_folios() to handle multi-page folios")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/f78ab50e-ed6d-4275-8dd4-a4159fa565a2@stanley.mountain
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>