[PATCH 0/3] tools/mm: page_owner_sort: three input-handling fixes

[Henrique Godoy]

These three patches are fixes for tools/mm/page_owner_sort.c and are
independent of the out-of-bounds series posted a moment ago; they touch the
record reader and the array of records.

1/3 keeps a record that ends the file.  A dump whose last record is not
    followed by an empty line loses that record: ten records load as nine,
    and the tenth disappears without a word.

2/3 stops reading a full buffer as the end of the file.  read_block()
    returns -1 both at the end of the file and when a record does not fit
    in BUF_SIZE, so a dump carrying a long record is sorted as if the file
    ended there:

      $ ./page_owner_sort dump.txt out.txt
      loaded 0

    With the patch it reports the record that does not fit, with the name
    of the file, and exits with a non-zero status.

3/3 grows the array of records instead of deriving its size from
    st.st_size / 100.  A dump whose records are shorter than 100 bytes
    holds more records than that, so a valid input is rejected:

      $ ./page_owner_sort dump.txt out.txt
      max_size too small??

    Measured on a dump of 200 records of 93 bytes: before, no output at
    all; after, all 200 records sorted.

The three inputs above are the reproduction cases: 9 records loaded before
and 10 after, "loaded 0" before and an error naming the file after, and
"max_size too small??" before and 200 records after.

The output of the tool on a realistic dump is byte for byte the same before
and after the series, and checkpatch --strict reports 0 errors, 0 warnings
and 0 checks on each patch.