Re: [PATCH 1/6] lib: include crc32.h conditionally on CONFIG_CRC32

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Using `#ifdef CONFIG_CRC32` breaks the build for modular drivers that rely on `eth_hw_addr_crc()`.
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commit 734658b27c8ae06b58089e30d3e39cd61c7d09d6
Author: Yury Norov <ynorov@nvidia.com>

lib: include crc32.h conditionally on CONFIG_CRC32

This commit restricts the inclusion of crc32.h and the definition of
eth_hw_addr_crc() in etherdevice.h to only when CONFIG_CRC32 is enabled.
This fixes implicit declaration errors when building tinyconfig where
CONFIG_BITREVERSE=n.

> diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
> index df8f88f63a706..d35be27a91a55 100644
> --- a/include/linux/etherdevice.h
> +++ b/include/linux/etherdevice.h
> @@ -20,7 +20,9 @@
>  #include <linux/if_ether.h>
>  #include <linux/netdevice.h>
>  #include <linux/random.h>
> +#ifdef CONFIG_CRC32
>  #include <linux/crc32.h>
> +#endif

Will this break the build for modular drivers?

CONFIG_CRC32 is a tristate option. When it is configured as a module (=m), the
build system defines CONFIG_CRC32_MODULE but not CONFIG_CRC32. Thus, the
preprocessor check evaluates to false.

Should this use #if IS_ENABLED(CONFIG_CRC32) instead to support both
built-in and modular configurations?

[ ... ]

> @@ -281,6 +283,7 @@ static inline void eth_hw_addr_random(struct net_device *dev)
>  	dev->addr_assign_type = NET_ADDR_RANDOM;
>  }
>  
> +#ifdef CONFIG_CRC32
>  /**
>   * eth_hw_addr_crc - Calculate CRC from netdev_hw_addr
>   * @ha: pointer to hardware address
> @@ -291,6 +294,7 @@ static inline u32 eth_hw_addr_crc(struct netdev_hw_addr *ha)
>  {
>  	return ether_crc(ETH_ALEN, ha->addr);
>  }
> +#endif

If CONFIG_CRC32 is built as a module, will modular network drivers that call
eth_hw_addr_crc() fail to compile due to an implicit declaration error since
this definition is hidden?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260430211351.658193-1-ynorov@nvidia.com?part=1