From: Nikolay Borisov <nborisov@suse.com>
To: Qu Wenruo <wqu@suse.com>, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 7/9] btrfs-progs: Fix Wmaybe-uninitialized warning
Date: Fri, 16 Nov 2018 10:13:02 +0200 [thread overview]
Message-ID: <05314eb4-29e5-8c30-05ca-5566ec12eb83@suse.com> (raw)
In-Reply-To: <20181116075426.4142-8-wqu@suse.com>
On 16.11.18 г. 9:54 ч., Qu Wenruo wrote:
> The only location is the following code:
>
> int level = path->lowest_level + 1;
> BUG_ON(path->lowest_level + 1 >= BTRFS_MAX_LEVEL);
> while(level < BTRFS_MAX_LEVEL) {
> slot = path->slots[level] + 1;
> ...
> }
> path->slots[level] = slot;
>
> Again, it's the stupid compiler needs some hint for the fact that
> we will always enter the while loop for at least once, thus @slot should
> always be initialized.
>
> Fix it by assign level after the BUG_ON(), so the stupid compiler knows
> we will always go into the while loop.
>
> Signed-off-by: Qu Wenruo <wqu@suse.com>
I don't get this warning on gcc 7.3. Also from your changelog it's not
really clear what the compiler is confused about.
Codewise lgtm:
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
> ---
> ctree.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/ctree.c b/ctree.c
> index 46e2ccedc0bf..9c9cb0dfdbf2 100644
> --- a/ctree.c
> +++ b/ctree.c
> @@ -2961,11 +2961,12 @@ int btrfs_next_sibling_tree_block(struct btrfs_fs_info *fs_info,
> struct btrfs_path *path)
> {
> int slot;
> - int level = path->lowest_level + 1;
> + int level;
> struct extent_buffer *c;
> struct extent_buffer *next = NULL;
>
> BUG_ON(path->lowest_level + 1 >= BTRFS_MAX_LEVEL);
> + level = path->lowest_level + 1;
> while(level < BTRFS_MAX_LEVEL) {
> if (!path->nodes[level])
> return 1;
>
next prev parent reply other threads:[~2018-11-16 8:13 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-16 7:54 [PATCH 0/9] btrfs-progs: Make W=1 clean (no "again") Qu Wenruo
2018-11-16 7:54 ` [PATCH 1/9] btrfs-progs: Makefile.extrawarn: Import cc-disable-warning Qu Wenruo
2018-12-04 11:04 ` David Sterba
2018-11-16 7:54 ` [PATCH 2/9] btrfs-progs: fix gcc8 default build warning caused by '-Wformat-truncation' Qu Wenruo
2018-12-04 11:10 ` David Sterba
2018-12-04 12:21 ` Qu Wenruo
2018-11-16 7:54 ` [PATCH 3/9] btrfs-progs: Makefile.extrawarn: Don't warn on sign compare Qu Wenruo
2018-11-16 8:00 ` [PATCH v1.1 " Qu Wenruo
2018-12-04 11:10 ` David Sterba
2018-11-16 7:54 ` [PATCH 4/9] btrfs-progs: Fix Wempty-body warning Qu Wenruo
2018-11-16 8:01 ` Nikolay Borisov
2018-11-16 7:54 ` [PATCH 5/9] btrfs-progs: Fix Wimplicit-fallthrough warning Qu Wenruo
2018-11-16 8:04 ` Nikolay Borisov
2018-11-16 8:10 ` Qu Wenruo
2018-11-16 7:54 ` [PATCH 6/9] btrfs-progs: Fix Wsuggest-attribute=format warning Qu Wenruo
2018-11-16 8:06 ` Nikolay Borisov
2018-11-16 7:54 ` [PATCH 7/9] btrfs-progs: Fix Wmaybe-uninitialized warning Qu Wenruo
2018-11-16 8:13 ` Nikolay Borisov [this message]
2018-11-16 8:16 ` Qu Wenruo
2018-11-16 8:22 ` [PATCH v1.1 " Qu Wenruo
2018-11-16 8:24 ` Nikolay Borisov
2018-12-04 12:17 ` [PATCH " David Sterba
2018-12-04 12:22 ` Adam Borowski
2018-12-04 12:42 ` Nikolay Borisov
2018-12-05 5:38 ` Qu Wenruo
2018-11-16 7:54 ` [PATCH 8/9] btrfs-progs: Fix Wtype-limits warning Qu Wenruo
2018-11-16 8:07 ` Nikolay Borisov
2018-11-16 7:54 ` [PATCH 9/9] btrfs-progs: Cleanup warning reported by -Wmissing-prototypes except free space tree Qu Wenruo
2018-11-16 8:04 ` [PATCH v1.1 9/9] btrfs-progs: Cleanup warning reported by -Wmissing-prototypes Qu Wenruo
2018-11-16 8:14 ` Nikolay Borisov
2018-12-04 12:22 ` David Sterba
2018-12-04 12:24 ` Qu Wenruo
2018-12-04 12:48 ` David Sterba
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