On Fri, Jan 29, 2021 at 06:58:56PM +0000, Vinicius Tinti wrote:
> By enabling -Wunreachable-code-aggressive on Clang the following code
> paths are unreachable.
>
> Commit dd73b5d5cb67 ("ext4: convert dx_probe() to use the ERR_PTR
> convention")
> Commit ac27a0ec112a ("[PATCH] ext4: initial copy of files from ext3")
>
> Clang warns:
>
> fs/ext4/namei.c:831:17: warning: code will never be executed
> [-Wunreachable-code]
> unsigned n = count - 1;
> ^~~~~
> fs/ext4/namei.c:830:7: note: silence by adding parentheses to mark code as
> explicitly dead
> if (0) { // linear search cross check
> ^
> /* DISABLES CODE */ ( )
The commit message might be a little clearer if it were restructured a
bit, maybe something like so?
By enabling -Wunreachable-code-aggressive on Clang, the following code
paths are unreachable:
fs/ext4/namei.c:831:17: warning: code will never be executed
[-Wunreachable-code]
unsigned n = count - 1;
^~~~~
fs/ext4/namei.c:830:7: note: silence by adding parentheses to mark code as
explicitly dead
if (0) { // linear search cross check
^
/* DISABLES CODE */ ( )
This has been present since commit ac27a0ec112a ("[PATCH] ext4: initial
copy of files from ext3") and fs/ext3 had it present at the beginning of
git history so it is safe to remove.
> Signed-off-by: Vinicius Tinti <viniciustinti@xxxxxxxxx>
Regardless of the commit message, I believe this is the right way to get
rid of the warning:
Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> ---
> fs/ext4/namei.c | 15 ---------------
> 1 file changed, 15 deletions(-)
>
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index cf652ba3e74d..1f64dbd7237b 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -827,21 +827,6 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
> p = m + 1;
> }
>
> - if (0) { // linear search cross check
> - unsigned n = count - 1;
> - at = entries;
> - while (n--)
> - {
> - dxtrace(printk(KERN_CONT ","));
> - if (dx_get_hash(++at) > hash)
> - {
> - at--;
> - break;
> - }
> - }
> - ASSERT(at == p - 1);
> - }
> -
> at = p - 1;
> dxtrace(printk(KERN_CONT " %x->%u\n",
> at == entries ? 0 : dx_get_hash(at),
> --
> 2.25.1
>
