[bug report] mm-add-apply_to_existing_pages-helper-fix

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Andrew Morton,

The patch 3264ba9274f5: "mm-add-apply_to_existing_pages-helper-fix"
from Dec 11, 2019, leads to the following static checker warning:

	mm/memory.c:2166 __apply_to_page_range()
	error: uninitialized symbol 'err'.

mm/memory.c
  2144  static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
  2145                                   unsigned long size, pte_fn_t fn,
  2146                                   void *data, bool create)
  2147  {
  2148          pgd_t *pgd;
  2149          unsigned long next;
  2150          unsigned long end = addr + size;
  2151          int err;
  2152  
  2153          if (WARN_ON(addr >= end))
  2154                  return -EINVAL;
  2155  
  2156          pgd = pgd_offset(mm, addr);
  2157          do {
  2158                  next = pgd_addr_end(addr, end);
  2159                  if (!create && pgd_none_or_clear_bad(pgd))
  2160                          continue;
                                ^^^^^^^^^
It feels unlikely that we would always hit this continue but Smatch
complains.

  2161                  err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create);
  2162                  if (err)
  2163                          break;
  2164          } while (pgd++, addr = next, addr != end);
  2165  
  2166          return err;
  2167  }

regards,
dan carpenter