LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Nick Desaulniers <ndesaulniers@google.com>
To: Louis Taylor <louis@kragniz.eu>
Cc: David Howells <dhowells@redhat.com>,
	linux-afs@lists.infradead.org,
	LKML <linux-kernel@vger.kernel.org>,
	clang-built-linux@googlegroups.com
Subject: Re: [PATCH v2] afs: use correct format characters
Date: Wed, 10 Apr 2019 15:52:25 -0700
Message-ID: <CAKwvOdmCHfRZ8miaCie=f2Fd_2QoJAnhS7TC8T0NYyQdcop9zA@mail.gmail.com> (raw)
In-Reply-To: <20190410224124.6901-1-louis@kragniz.eu>

On Wed, Apr 10, 2019 at 3:41 PM Louis Taylor <louis@kragniz.eu> wrote:
>
> When compiling with -Wformat, clang warns:
>
> fs/afs/flock.c:632:29: warning: format specifies type 'short' but the argument has type
>       'unsigned char' [-Wformat]
>         _leave(" = %d [%hd]", ret, fl->fl_type);
>                        ~~~         ^~~~~~~~~~~
>
> fs/afs/dir.c:138:11: warning: format specifies type 'unsigned short' but
> the argument has type 'int' [-Wformat]
>        ntohs(dbuf->blocks[tmp].hdr.magic));
>        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> fl_type is declared as an unsigned char unconditionally in
> include/linux/fs.h, so use the correct format characters.

Thanks for the v2, probably should include a note about ntohs.  That
case in particular looks more complicated, due to the definition of
ntohs (which uses __swab16).

If you keep the previous flag of %04hx, but add an explicit cast to
u16, does the warning go away? If so, that might be a better fix.

- ntohs(dbuf->blocks[tmp].hdr.magic));
+ (u16)ntohs(dbuf->blocks[tmp].hdr.magic));

?

Particularly, I'm curious about the return type of GNU C statement
expressions, in the definition of __swab16 if __HAVE_BUILTIN_BSWAP16__
is not defined.

>
> Link: https://github.com/ClangBuiltLinux/linux/issues/378
> Signed-off-by: Louis Taylor <louis@kragniz.eu>
> ---
>  fs/afs/dir.c   | 2 +-
>  fs/afs/flock.c | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/afs/dir.c b/fs/afs/dir.c
> index 8a2562e3a316..4ceaec94e9c5 100644
> --- a/fs/afs/dir.c
> +++ b/fs/afs/dir.c
> @@ -133,7 +133,7 @@ static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
>         dbuf = kmap(page);
>         for (tmp = 0; tmp < qty; tmp++) {
>                 if (dbuf->blocks[tmp].hdr.magic != AFS_DIR_MAGIC) {
> -                       printk("kAFS: %s(%lx): bad magic %d/%d is %04hx\n",
> +                       printk("kAFS: %s(%lx): bad magic %d/%d is %04x\n",
>                                __func__, dvnode->vfs_inode.i_ino, tmp, qty,
>                                ntohs(dbuf->blocks[tmp].hdr.magic));
>                         trace_afs_dir_check_failed(dvnode, off, i_size);
> diff --git a/fs/afs/flock.c b/fs/afs/flock.c
> index 6a0174258382..be4c3f6a3178 100644
> --- a/fs/afs/flock.c
> +++ b/fs/afs/flock.c
> @@ -629,7 +629,7 @@ static int afs_do_getlk(struct file *file, struct file_lock *fl)
>
>         ret = 0;
>  error:
> -       _leave(" = %d [%hd]", ret, fl->fl_type);
> +       _leave(" = %d [%hhu]", ret, fl->fl_type);
>         return ret;
>  }

-
Thanks,
~Nick Desaulniers

  reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-10 22:03 [PATCH] " Louis Taylor
2019-04-10 22:27 ` Nick Desaulniers
2019-04-10 22:41 ` [PATCH v2] " Louis Taylor
2019-04-10 22:52   ` Nick Desaulniers [this message]
2019-04-12 15:48     ` David Laight
2019-04-10 23:00 ` [PATCH] " Joe Perches
2019-04-11 16:31   ` Linus Torvalds
2019-04-11 17:41     ` Nick Desaulniers

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAKwvOdmCHfRZ8miaCie=f2Fd_2QoJAnhS7TC8T0NYyQdcop9zA@mail.gmail.com' \
    --to=ndesaulniers@google.com \
    --cc=clang-built-linux@googlegroups.com \
    --cc=dhowells@redhat.com \
    --cc=linux-afs@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=louis@kragniz.eu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git
	git clone --mirror https://lore.kernel.org/lkml/10 lkml/git/10.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git