| Message ID | 20180528155432.2864616-1-arnd@arndb.de (mailing list archive) |
|---|---|
| State | Rejected, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
On Mon, May 28 2018 at 11:54am -0400, Arnd Bergmann <arnd@arndb.de> wrote: > The return type of ACCESS_ONCE is configuration dependent and may be either > 'int' or 'long int' for the writecache_has_error() macro, so we get a warning > like this for either format string: > > In file included from drivers/md/dm-writecache.c:8: > drivers/md/dm-writecache.c: In function 'writecache_status': > drivers/md/dm-writecache.c:2227:10: error: format '%ld' expects argument of type 'long int', but argument 4 has type 'int' [-Werror=format=] > DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc), > ^~~~~~~~~~~~~~~~~~~~ > include/linux/device-mapper.h:549:46: note: in definition of macro 'DMEMIT' > 0 : scnprintf(result + sz, maxlen - sz, x)) > ^ > > The code is otherwise correct, so we just need to shut up the warning, > which can be done using an extra type cast. > > Fixes: bb15b431d650 ("dm: add writecache target") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Thanks, I've picked this up. -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
On Mon, 28 May 2018, Arnd Bergmann wrote: > The return type of ACCESS_ONCE is configuration dependent and may be either > 'int' or 'long int' for the writecache_has_error() macro, so we get a warning > like this for either format string: __builtin_expect returns always long, see the GCC documentation (it used to return int in very old gcc versions such as 2.96). I think this is a bug in the macro __branch_check__. The variable ______r should be long, but it is int. This bug may cause misbehavior of other kernel parts (i.e. truncation of long value to int), so it should be fixed in __branch_check__ - not in dm-writecache. Mikulas > In file included from drivers/md/dm-writecache.c:8: > drivers/md/dm-writecache.c: In function 'writecache_status': > drivers/md/dm-writecache.c:2227:10: error: format '%ld' expects argument of type 'long int', but argument 4 has type 'int' [-Werror=format=] > DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc), > ^~~~~~~~~~~~~~~~~~~~ > include/linux/device-mapper.h:549:46: note: in definition of macro 'DMEMIT' > 0 : scnprintf(result + sz, maxlen - sz, x)) > ^ > > The code is otherwise correct, so we just need to shut up the warning, > which can be done using an extra type cast. > > Fixes: bb15b431d650 ("dm: add writecache target") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/md/dm-writecache.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c > index 1ef06e738eb6..772ac3a57287 100644 > --- a/drivers/md/dm-writecache.c > +++ b/drivers/md/dm-writecache.c > @@ -2224,7 +2224,7 @@ static void writecache_status(struct dm_target *ti, status_type_t type, > > switch (type) { > case STATUSTYPE_INFO: > - DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc), > + DMEMIT("%ld %llu %llu %llu", (long)writecache_has_error(wc), > (unsigned long long)wc->n_blocks, (unsigned long long)wc->freelist_size, > (unsigned long long)wc->writeback_size); > break; > -- > 2.9.0 > -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c index 1ef06e738eb6..772ac3a57287 100644 --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -2224,7 +2224,7 @@ static void writecache_status(struct dm_target *ti, status_type_t type, switch (type) { case STATUSTYPE_INFO: - DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc), + DMEMIT("%ld %llu %llu %llu", (long)writecache_has_error(wc), (unsigned long long)wc->n_blocks, (unsigned long long)wc->freelist_size, (unsigned long long)wc->writeback_size); break;
The return type of ACCESS_ONCE is configuration dependent and may be either 'int' or 'long int' for the writecache_has_error() macro, so we get a warning like this for either format string: In file included from drivers/md/dm-writecache.c:8: drivers/md/dm-writecache.c: In function 'writecache_status': drivers/md/dm-writecache.c:2227:10: error: format '%ld' expects argument of type 'long int', but argument 4 has type 'int' [-Werror=format=] DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc), ^~~~~~~~~~~~~~~~~~~~ include/linux/device-mapper.h:549:46: note: in definition of macro 'DMEMIT' 0 : scnprintf(result + sz, maxlen - sz, x)) ^ The code is otherwise correct, so we just need to shut up the warning, which can be done using an extra type cast. Fixes: bb15b431d650 ("dm: add writecache target") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/md/dm-writecache.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)