[PATCH] memory: tegra20-emc: replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE

[PATCH] memory: tegra20-emc: replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE

[Bo Liu]

Fix the following coccicheck warning:
 drivers/memory/tegra/tegra20-emc.c:902:0-23: WARNING:
  tegra_emc_debug_max_rate_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE
 drivers/memory/tegra/tegra20-emc.c:872:0-23: WARNING:
  tegra_emc_debug_min_rate_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE

Signed-off-by: Bo Liu <liubo03@inspur.com>
---
 drivers/memory/tegra/tegra20-emc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
index bd4e37b6552d..c2b4caccfae9 100644
--- a/drivers/memory/tegra/tegra20-emc.c
+++ b/drivers/memory/tegra/tegra20-emc.c
@@ -869,7 +869,7 @@ static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
 	return 0;
 }
 
-DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
+DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
 			tegra_emc_debug_min_rate_get,
 			tegra_emc_debug_min_rate_set, "%llu\n");
 
@@ -899,7 +899,7 @@ static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
 	return 0;
 }
 
-DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
+DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
 			tegra_emc_debug_max_rate_get,
 			tegra_emc_debug_max_rate_set, "%llu\n");
 
-- 
2.27.0

Re: [PATCH] memory: tegra20-emc: replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE

[Thierry Reding]

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On Tue, Nov 01, 2022 at 04:16:11AM -0400, Bo Liu wrote:
> Fix the following coccicheck warning:
>  drivers/memory/tegra/tegra20-emc.c:902:0-23: WARNING:
>   tegra_emc_debug_max_rate_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE
>  drivers/memory/tegra/tegra20-emc.c:872:0-23: WARNING:
>   tegra_emc_debug_min_rate_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE
> 
> Signed-off-by: Bo Liu <liubo03@inspur.com>
> ---
>  drivers/memory/tegra/tegra20-emc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

This seems incomplete: the rationale in that debugfs cocci script says
that DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe() is the
pattern to use vs. the less efficient DEFINE_SIMPLE_ATTRIBUTE +
debugfs_create_file(). So this patch should probably use the unsafe
function variant at the same time to take full advantage.

Thierry

> 
> diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
> index bd4e37b6552d..c2b4caccfae9 100644
> --- a/drivers/memory/tegra/tegra20-emc.c
> +++ b/drivers/memory/tegra/tegra20-emc.c
> @@ -869,7 +869,7 @@ static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
>  	return 0;
>  }
>  
> -DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
> +DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
>  			tegra_emc_debug_min_rate_get,
>  			tegra_emc_debug_min_rate_set, "%llu\n");
>  
> @@ -899,7 +899,7 @@ static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
>  	return 0;
>  }
>  
> -DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
> +DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
>  			tegra_emc_debug_max_rate_get,
>  			tegra_emc_debug_max_rate_set, "%llu\n");
>  
> -- 
> 2.27.0
> 

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Re: [PATCH] memory: tegra20-emc: replace DEFINE_SIMPLE_ATTRIBUTE with DEFINE_DEBUGFS_ATTRIBUTE

[Thierry Reding]

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On Tue, Nov 01, 2022 at 12:52:14PM +0100, Thierry Reding wrote:
> On Tue, Nov 01, 2022 at 04:16:11AM -0400, Bo Liu wrote:
> > Fix the following coccicheck warning:
> >  drivers/memory/tegra/tegra20-emc.c:902:0-23: WARNING:
> >   tegra_emc_debug_max_rate_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE
> >  drivers/memory/tegra/tegra20-emc.c:872:0-23: WARNING:
> >   tegra_emc_debug_min_rate_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE
> > 
> > Signed-off-by: Bo Liu <liubo03@inspur.com>
> > ---
> >  drivers/memory/tegra/tegra20-emc.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> This seems incomplete: the rationale in that debugfs cocci script says
> that DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe() is the
> pattern to use vs. the less efficient DEFINE_SIMPLE_ATTRIBUTE +
> debugfs_create_file(). So this patch should probably use the unsafe
> function variant at the same time to take full advantage.

That said, I'm not even sure if these attributes would qualify for
debugfs_create_file_unsafe() since there's really no protection against
removal.

Overall that cocci seems a bit misleading in that it makes these changes
seem like trivial conversions. Only converting DEFINE_SIMPLE_ATTRIBUTE()
to DEFINE_DEBUGFS_ATTRIBUTE() is basically a noop, except that debugfs
has a little more overhead (for example debugfs_attr_read() wraps
simple_attr_read()), so I'm not sure if that's worth doing on its own.

Thierry

> > 
> > diff --git a/drivers/memory/tegra/tegra20-emc.c b/drivers/memory/tegra/tegra20-emc.c
> > index bd4e37b6552d..c2b4caccfae9 100644
> > --- a/drivers/memory/tegra/tegra20-emc.c
> > +++ b/drivers/memory/tegra/tegra20-emc.c
> > @@ -869,7 +869,7 @@ static int tegra_emc_debug_min_rate_set(void *data, u64 rate)
> >  	return 0;
> >  }
> >  
> > -DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
> > +DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_min_rate_fops,
> >  			tegra_emc_debug_min_rate_get,
> >  			tegra_emc_debug_min_rate_set, "%llu\n");
> >  
> > @@ -899,7 +899,7 @@ static int tegra_emc_debug_max_rate_set(void *data, u64 rate)
> >  	return 0;
> >  }
> >  
> > -DEFINE_SIMPLE_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
> > +DEFINE_DEBUGFS_ATTRIBUTE(tegra_emc_debug_max_rate_fops,
> >  			tegra_emc_debug_max_rate_get,
> >  			tegra_emc_debug_max_rate_set, "%llu\n");
> >  
> > -- 
> > 2.27.0
> > 



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