Subject: linux-next: build warning after merge of the vhost tree

From: Stephen Rothwell <[email-masked]>
Date: Mon, 16 Dec 2019 14:49:40 +1100

Hi all,

After merging the vhost tree, today's linux-next build (powerpc
ppc64_defconfig) produced this warning:

In file included from include/linux/list.h:9,
                 from include/linux/preempt.h:11,
                 from include/linux/spinlock.h:51,
                 from include/linux/seqlock.h:36,
                 from include/linux/time.h:6,
                 from include/linux/stat.h:19,
                 from include/linux/fcntl.h:5,
                 from include/linux/eventfd.h:12,
                 from drivers/vhost/vhost.c:13:
drivers/vhost/vhost.c: In function 'vhost_log_write':
include/linux/kernel.h:844:29: warning: comparison of distinct pointer types lacks a cast
  844 |   (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
      |                             ^~
include/linux/kernel.h:858:4: note: in expansion of macro '__typecheck'
  858 |   (__typecheck(x, y) && __no_side_effects(x, y))
      |    ^~~~~~~~~~~
include/linux/kernel.h:868:24: note: in expansion of macro '__safe_cmp'
  868 |  __builtin_choose_expr(__safe_cmp(x, y), \
      |                        ^~~~~~~~~~
include/linux/kernel.h:877:19: note: in expansion of macro '__careful_cmp'
  877 | #define min(x, y) __careful_cmp(x, y, <)
      |                   ^~~~~~~~~~~~~
drivers/vhost/vhost.c:1968:11: note: in expansion of macro 'min'
 1968 |   u64 l = min(log[i].len, len);
      |           ^~~

Introduced by commit

  b072ae74df17 ("vhost: use vhost_desc instead of vhost_log")

vhost_log::len was u64 and vhost_desc::len is u32 and len is u64.

-- 
Cheers,
Stephen Rothwell