Re: [PATCH] powerpc/cell/axon_msi: replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE

From: Michael Ellerman
Date: Tue Dec 21 2021 - 19:08:50 EST


cgel.zte@xxxxxxxxx writes:
> From: Changcheng Deng <deng.changcheng@xxxxxxxxxx>
>
> Fix the following coccicheck warning:
> ./arch/powerpc/platforms/cell/axon_msi.c: 456: 0-23: WARNING: fops_msic
> should be defined with DEFINE_DEBUGFS_ATTRIBUTE
>
> Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE for
> debugfs files.

But it also says:

//# Rationale: DEFINE_SIMPLE_ATTRIBUTE + debugfs_create_file()
//# imposes some significant overhead as compared to
//# DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe().

Your patch doesn't change it to use debugfs_create_file_unsafe(),
shouldn't it?

cheers

> diff --git a/arch/powerpc/platforms/cell/axon_msi.c b/arch/powerpc/platforms/cell/axon_msi.c
> index 354a58c1e6f2..47bb0ae8d6c9 100644
> --- a/arch/powerpc/platforms/cell/axon_msi.c
> +++ b/arch/powerpc/platforms/cell/axon_msi.c
> @@ -453,7 +453,7 @@ static int msic_get(void *data, u64 *val)
> return 0;
> }
>
> -DEFINE_SIMPLE_ATTRIBUTE(fops_msic, msic_get, msic_set, "%llu\n");
> +DEFINE_DEBUGFS_ATTRIBUTE(fops_msic, msic_get, msic_set, "%llu\n");
>
> void axon_msi_debug_setup(struct device_node *dn, struct axon_msic *msic)
> {
> --
> 2.25.1