[PATCH] vfs: Adjust indentation in remap_verify_area

[PATCH] vfs: Adjust indentation in remap_verify_area

[Nathan Chancellor]

Clang warns:

../fs/read_write.c:1760:3: warning: misleading indentation; statement is
not part of the previous 'if' [-Wmisleading-indentation]
         if (unlikely((loff_t) (pos + len) < 0))
         ^
../fs/read_write.c:1757:2: note: previous statement is here
        if (unlikely(pos < 0 || len < 0))
        ^
1 warning generated.

This warning occurs because there is a space after the tab on this line.
Remove it so that the indentation is consistent with the Linux kernel
coding style and clang no longer warns.

Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer")
Link: https://github.com/ClangBuiltLinux/linux/issues/828
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 fs/read_write.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index 5bbf587f5bc1..c71e863163bd 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1757,7 +1757,7 @@ static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
 	if (unlikely(pos < 0 || len < 0))
 		return -EINVAL;
 
-	 if (unlikely((loff_t) (pos + len) < 0))
+	if (unlikely((loff_t) (pos + len) < 0))
 		return -EINVAL;
 
 	if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
-- 
2.24.1

Re: [PATCH] vfs: Adjust indentation in remap_verify_area

[Al Viro]

On Tue, Dec 17, 2019 at 08:23:51PM -0700, Nathan Chancellor wrote:
> Clang warns:
> 
> ../fs/read_write.c:1760:3: warning: misleading indentation; statement is
> not part of the previous 'if' [-Wmisleading-indentation]
>          if (unlikely((loff_t) (pos + len) < 0))
>          ^
> ../fs/read_write.c:1757:2: note: previous statement is here
>         if (unlikely(pos < 0 || len < 0))
>         ^
> 1 warning generated.
> 
> This warning occurs because there is a space after the tab on this line.
> Remove it so that the indentation is consistent with the Linux kernel
> coding style and clang no longer warns.
> 
> Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer")
> Link: https://github.com/ClangBuiltLinux/linux/issues/828
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

Egads...  This commit message is way, way over the top.

1) the warning is more obscure than the problem it points to.

2) simple "statement accidentally indented one column too deep"
would do just fine

3) crediting the tool is generally a good idea, but in situation
when the quality of warning is that low you'd be better paraphrasing
it and mentioning the tool that has pointed it out.  No need to quote
the verbiage.

[PATCH v2] vfs: Adjust indentation in remap_verify_area

[Nathan Chancellor]

Clang's -Wmisleading-indentation caught an instance in remap_verify_area
where there was a trailing space after a tab. Remove it to get rid of
the warning.

Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer")
Link: https://github.com/ClangBuiltLinux/linux/issues/828
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---

v1 -> v2:

* Trim warning and simplify patch explanation.

 fs/read_write.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/read_write.c b/fs/read_write.c
index 5bbf587f5bc1..c71e863163bd 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1757,7 +1757,7 @@ static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
 	if (unlikely(pos < 0 || len < 0))
 		return -EINVAL;
 
-	 if (unlikely((loff_t) (pos + len) < 0))
+	if (unlikely((loff_t) (pos + len) < 0))
 		return -EINVAL;
 
 	if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
-- 
2.24.1

Re: [PATCH v2] vfs: Adjust indentation in remap_verify_area

[David Sterba]

On Tue, Dec 17, 2019 at 10:16:35PM -0700, Nathan Chancellor wrote:
> Clang's -Wmisleading-indentation caught an instance in remap_verify_area
> where there was a trailing space after a tab. Remove it to get rid of
> the warning.
> 
> Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer")
> Link: https://github.com/ClangBuiltLinux/linux/issues/828
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> 
> v1 -> v2:
> 
> * Trim warning and simplify patch explanation.
> 
>  fs/read_write.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/read_write.c b/fs/read_write.c
> index 5bbf587f5bc1..c71e863163bd 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -1757,7 +1757,7 @@ static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
>  	if (unlikely(pos < 0 || len < 0))
>  		return -EINVAL;
>  
> -	 if (unlikely((loff_t) (pos + len) < 0))
> +	if (unlikely((loff_t) (pos + len) < 0))

Instead of just fixing whitespace, can we please fix the undefined
behaviour on this line? pos and len are signed types, there's a helper
to do that in a way that's UB-safe.

And btw here's a patch:

https://lore.kernel.org/linux-fsdevel/20190808123942.19592-1-dsterba@suse.com/

Re: [PATCH v2] vfs: Adjust indentation in remap_verify_area

[Nathan Chancellor]

On Wed, Dec 18, 2019 at 12:04:37PM +0100, David Sterba wrote:
> On Tue, Dec 17, 2019 at 10:16:35PM -0700, Nathan Chancellor wrote:
> > Clang's -Wmisleading-indentation caught an instance in remap_verify_area
> > where there was a trailing space after a tab. Remove it to get rid of
> > the warning.
> > 
> > Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer")
> > Link: https://github.com/ClangBuiltLinux/linux/issues/828
> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> > ---
> > 
> > v1 -> v2:
> > 
> > * Trim warning and simplify patch explanation.
> > 
> >  fs/read_write.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/read_write.c b/fs/read_write.c
> > index 5bbf587f5bc1..c71e863163bd 100644
> > --- a/fs/read_write.c
> > +++ b/fs/read_write.c
> > @@ -1757,7 +1757,7 @@ static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
> >  	if (unlikely(pos < 0 || len < 0))
> >  		return -EINVAL;
> >  
> > -	 if (unlikely((loff_t) (pos + len) < 0))
> > +	if (unlikely((loff_t) (pos + len) < 0))
> 
> Instead of just fixing whitespace, can we please fix the undefined
> behaviour on this line? pos and len are signed types, there's a helper
> to do that in a way that's UB-safe.
> 
> And btw here's a patch:
> 
> https://lore.kernel.org/linux-fsdevel/20190808123942.19592-1-dsterba@suse.com/

I do not particularly care how this warning gets fixed, just that it
does. I will review that patch like Nick did.

Cheers,
Nathan