linux-kernel - Re: [PATCH 1/2] dma/pool: trivial: add semicolon after label attributes

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Message-ID: <20230829151216.GA4211@lst.de>
Date:   Tue, 29 Aug 2023 17:12:16 +0200
From:   Christoph Hellwig <hch@....de>
To:     Robin Murphy <robin.murphy@....com>
Cc:     Chunhui He <hchunhui@...l.ustc.edu.cn>,
        Christoph Hellwig <hch@....de>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        iommu@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] dma/pool: trivial: add semicolon after label
 attributes

On Tue, Aug 29, 2023 at 03:22:22PM +0100, Robin Murphy wrote:
> AFAICS, what that clearly says is that *C++* label attributes can be 
> ambiguous. This is not C++ code. Even in C11, declarations still cannot be 
> labelled, so it should still be the case that, per the same GCC 
> documentation, "the ambiguity does not arise". And even if the language did 
> allow it, an inline declaration at that point at the end of a function 
> would be downright weird and against the kernel coding style anyway.
>
> So, I don't really see what's "better" about cluttering up C code with 
> unnecessary C++isms; it's just weird noise to me. The only thing I think it 
> *does* achieve is introduce the chance that the static checker brigade 
> eventually identifies a redundant semicolon and we get more patches to 
> remove it again.

Agreed.  Even more importantly that attribute looks rather questionable
to start with as it can be dropped by just moving the #endif a little:

diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 1acec2e228273f..da03c4a57cebe3 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -135,8 +135,8 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
 remove_mapping:
 #ifdef CONFIG_DMA_DIRECT_REMAP
 	dma_common_free_remap(addr, pool_size);
+free_page:
 #endif
-free_page: __maybe_unused
 	__free_pages(page, order);
 out:
 	return ret;