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 [thread overview]
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
next prev parent reply other threads:[~2019-04-10 22:52 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-10 22:03 [PATCH] afs: use correct format characters 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
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