releases/4.9.52/bcache-correct-return-value-for-sysfs-attach-errors.patch

   1 From 77fa100f27475d08a569b9d51c17722130f089e7 Mon Sep 17 00:00:00 2001
   2 From: Tony Asleson <tasleson@redhat.com>
   3 Date: Wed, 6 Sep 2017 14:25:57 +0800
   4 Subject: bcache: Correct return value for sysfs attach errors
   5
   6 From: Tony Asleson <tasleson@redhat.com>
   7
   8 commit 77fa100f27475d08a569b9d51c17722130f089e7 upstream.
   9
  10 If you encounter any errors in bch_cached_dev_attach it will return
  11 a negative error code.  The variable 'v' which stores the result is
  12 unsigned, thus user space sees a very large value returned for bytes
  13 written which can cause incorrect user space behavior.  Utilize 1
  14 signed variable to use throughout the function to preserve error return
  15 capability.
  16
  17 Signed-off-by: Tony Asleson <tasleson@redhat.com>
  18 Acked-by: Coly Li <colyli@suse.de>
  19 Signed-off-by: Jens Axboe <axboe@kernel.dk>
  20 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  21
  22 ---
  23  drivers/md/bcache/sysfs.c |    4 ++--
  24  1 file changed, 2 insertions(+), 2 deletions(-)
  25
  26 --- a/drivers/md/bcache/sysfs.c
  27 +++ b/drivers/md/bcache/sysfs.c
  28 @@ -191,7 +191,7 @@ STORE(__cached_dev)
  29  {
  30         struct cached_dev *dc = container_of(kobj, struct cached_dev,
  31                                              disk.kobj);
  32 -       unsigned v = size;
  33 +       ssize_t v = size;
  34         struct cache_set *c;
  35         struct kobj_uevent_env *env;
  36
  37 @@ -226,7 +226,7 @@ STORE(__cached_dev)
  38                 bch_cached_dev_run(dc);
  39
  40         if (attr == &sysfs_cache_mode) {
  41 -               ssize_t v = bch_read_string_list(buf, bch_cache_modes + 1);
  42 +               v = bch_read_string_list(buf, bch_cache_modes + 1);
  43
  44                 if (v < 0)
  45                         return v;