From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: New bcache compiler warning (was: Re: bcache: Minor fixes from kbuild robot) Date: Mon, 17 Feb 2014 13:45:53 -0800 Message-ID: <20140217214553.GB11655@kmo> References: <530279EC.5010605@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Geert Uytterhoeven Cc: Randy Dunlap , Linux Kernel Mailing List , linux-bcache@vger.kernel.org List-Id: linux-bcache@vger.kernel.org On Mon, Feb 17, 2014 at 10:11:51PM +0100, Geert Uytterhoeven wrote: > On Mon, Feb 17, 2014 at 10:06 PM, Randy Dunlap wrote: > > On 02/17/2014 01:00 PM, Geert Uytterhoeven wrote: > >> On Fri, Feb 14, 2014 at 8:04 PM, Linux Kernel Mailing List > >> wrote: > >>> bcache: Minor fixes from kbuild robot > >> > >>> diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c > >>> index 4f6b594..3f74b4b 100644 > >>> --- a/drivers/md/bcache/bset.c > >>> +++ b/drivers/md/bcache/bset.c > >>> @@ -23,7 +23,7 @@ void bch_dump_bset(struct btree_keys *b, struct= bset *i, unsigned set) > >>> for (k =3D i->start; k < bset_bkey_last(i); k =3D next) { > >>> next =3D bkey_next(k); > >>> > >>> - printk(KERN_ERR "block %u key %zi/%u: ", set, > >>> + printk(KERN_ERR "block %u key %li/%u: ", set, > >>> (uint64_t *) k - i->d, i->keys); > >>> > >>> if (b->ops->key_dump) > >> > >> On 32-bit (m68k): > >> drivers/md/bcache/bset.c: In function =E2=80=98bch_dump_bset=E2=80= =99: > >> drivers/md/bcache/bset.c:27: warning: format =E2=80=98%li=E2=80=99= expects type =E2=80=98long > >> int=E2=80=99, but argument 3 has type =E2=80=98int=E2=80=99 > >> > >> What are you trying to print here? It looks a bit strange to me. > >> Technically, the difference between two pointers is of type ptrdif= f_. > >> The kernel had > >> > >> typedef __kernel_ptrdiff_t ptrdiff_t; > >> > >> and > >> > >> #if __BITS_PER_LONG !=3D 64 > >> typedef unsigned int __kernel_size_t; > >> typedef int __kernel_ssize_t; > >> typedef int __kernel_ptrdiff_t; > >> #else > >> typedef __kernel_ulong_t __kernel_size_t; > >> typedef __kernel_long_t __kernel_ssize_t; > >> typedef __kernel_long_t __kernel_ptrdiff_t; > >> #endif > >> > >> So I'd expect "%zi" to be the right way, and a quick test compile = on > >> 32-bit (m68k) > >> and 64-bit (amd64) comfirms that. What was wrong with it? > > > > The kernel supports 't' (%t) for ptrdiff_t (same as glibc), > > so %ti should work (or %tu). >=20 > Yes, that compiles without warnings, too. >=20 > And after more decyphering, "(uint64_t *) k - i->d" seems to be posit= ive, > so "%tu" should be OK. *swears* Actually, I'm just going to cast this to unsigned (that's defi= nitely safe here): commit 70bc49d421c793f73a772ae1f50622a39c6136d9 Author: Kent Overstreet Date: Mon Feb 17 13:44:06 2014 -0800 bcache: Fix another compiler warning on m68k =20 Use a bigger hammer this time =20 Signed-off-by: Kent Overstreet diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c index 3f74b4b074..5454164153 100644 --- a/drivers/md/bcache/bset.c +++ b/drivers/md/bcache/bset.c @@ -23,8 +23,8 @@ void bch_dump_bset(struct btree_keys *b, struct bset = *i, unsigned set) for (k =3D i->start; k < bset_bkey_last(i); k =3D next) { next =3D bkey_next(k); =20 - printk(KERN_ERR "block %u key %li/%u: ", set, - (uint64_t *) k - i->d, i->keys); + printk(KERN_ERR "block %u key %u/%u: ", set, + (unsigned) ((u64 *) k - i->d), i->keys); =20 if (b->ops->key_dump) b->ops->key_dump(b, k);