md: change mddev 'chunk_sectors' from int to unsigned

Commit e2782f560c29 ("Revert "dm raid: remove unnecessary discard
limits for raid10"") exposed compiler warnings introduced by commit
e0910c8e4f87 ("dm raid: fix discard limits for raid1 and raid10"):

In file included from ./include/linux/kernel.h:14,
                 from ./include/asm-generic/bug.h:20,
                 from ./arch/x86/include/asm/bug.h:93,
                 from ./include/linux/bug.h:5,
                 from ./include/linux/mmdebug.h:5,
                 from ./include/linux/gfp.h:5,
                 from ./include/linux/slab.h:15,
                 from drivers/md/dm-raid.c:8:
drivers/md/dm-raid.c: In function ‘raid_io_hints’:
./include/linux/minmax.h:18:28: warning: comparison of distinct pointer types lacks a cast
  (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                            ^~
./include/linux/minmax.h:32:4: note: in expansion of macro ‘__typecheck’
   (__typecheck(x, y) && __no_side_effects(x, y))
    ^~~~~~~~~~~
./include/linux/minmax.h:42:24: note: in expansion of macro ‘__safe_cmp’
  __builtin_choose_expr(__safe_cmp(x, y), \
                        ^~~~~~~~~~
./include/linux/minmax.h:51:19: note: in expansion of macro ‘__careful_cmp’
 #define min(x, y) __careful_cmp(x, y, <)
                   ^~~~~~~~~~~~~
./include/linux/minmax.h:84:39: note: in expansion of macro ‘min’
  __x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
                                       ^~~
drivers/md/dm-raid.c:3739:33: note: in expansion of macro ‘min_not_zero’
   limits->max_discard_sectors = min_not_zero(rs->md.chunk_sectors,
                                 ^~~~~~~~~~~~

Fix this by changing the chunk_sectors member of 'struct mddev' from
int to 'unsigned int' to match the type used for the 'chunk_sectors'
member of 'struct queue_limits'.  Various MD code still uses 'int' but
none of it appears to ever make use of signed int; and storing
positive signed int in unsigned is perfectly safe.

Reported-by: Song Liu <songliubraving@fb.com>
Fixes: e2782f560c29 ("Revert "dm raid: remove unnecessary discard limits for raid10"")
Fixes: e0910c8e4f87 ("dm raid: fix discard limits for raid1 and raid10")
Cc: stable@vger,kernel.org # e0910c8e4f87 was marked for stable@
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 2175a5a..bb645bc 100644 (file)
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -311,7 +311,7 @@ struct mddev {
        int                             external;       /* metadata is
                                                         * managed externally */
        char                            metadata_type[17]; /* externally set*/
-       int                             chunk_sectors;
+       unsigned int                    chunk_sectors;
        time64_t                        ctime, utime;
        int                             level, layout;
        char                            clevel[16];
@@ -339,7 +339,7 @@ struct mddev {
         */
        sector_t                        reshape_position;
        int                             delta_disks, new_level, new_layout;
-       int                             new_chunk_sectors;
+       unsigned int                    new_chunk_sectors;
        int                             reshape_backwards;
 
        struct md_thread                *thread;        /* management thread */