On Wed, Jan 11, 2023 at 01:53:34AM +0530, Deepak R Varma wrote:
> Using DEFINE_SIMPLE_ATTRIBUTE macro with the debugfs_create_file()
> function adds the overhead of introducing a proxy file operation
> functions to wrap the original read/write inside file removal protection
> functions. This adds significant overhead in terms of introducing and
> managing the proxy factory file operations structure and function
> wrapping at runtime.
> As a replacement, a combination of DEFINE_DEBUGFS_ATTRIBUTE macro paired
> with debugfs_create_file_unsafe() is suggested to be used instead. The
> DEFINE_DEBUGFS_ATTRIBUTE utilises debugfs_file_get() and
> debugfs_file_put() wrappers to protect the original read and write
> function calls for the debug attributes. There is no need for any
> runtime proxy file operations to be managed by the debugfs core.
> Following coccicheck make command helped identify this change:
>
> make coccicheck M=drivers/gpu/drm/i915/ MODE=patch COCCI=./scripts/coccinelle/api/debugfs/debugfs_simple_attr.cocci
>
> Signed-off-by: Deepak R Varma <drv@xxxxxxxxx>
Acked-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Anyone up for testing this change?
I have never dealt with debugfs so dunno if the chnage will work or not.
Sam
> ---
> Note: Patch compile tested only.
>
> drivers/gpu/drm/panel/panel-sitronix-st7703.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7703.c b/drivers/gpu/drm/panel/panel-sitronix-st7703.c
> index 86a472b01360..22ed7e2b0e00 100644
> --- a/drivers/gpu/drm/panel/panel-sitronix-st7703.c
> +++ b/drivers/gpu/drm/panel/panel-sitronix-st7703.c
> @@ -510,15 +510,14 @@ static int allpixelson_set(void *data, u64 val)
> return 0;
> }
>
> -DEFINE_SIMPLE_ATTRIBUTE(allpixelson_fops, NULL,
> - allpixelson_set, "%llu\n");
> +DEFINE_DEBUGFS_ATTRIBUTE(allpixelson_fops, NULL, allpixelson_set, "%llu\n");
>
> static void st7703_debugfs_init(struct st7703 *ctx)
> {
> ctx->debugfs = debugfs_create_dir(DRV_NAME, NULL);
>
> - debugfs_create_file("allpixelson", 0600, ctx->debugfs, ctx,
> - &allpixelson_fops);
> + debugfs_create_file_unsafe("allpixelson", 0600, ctx->debugfs, ctx,
> + &allpixelson_fops);
> }
>
> static void st7703_debugfs_remove(struct st7703 *ctx)
> --
> 2.34.1
>
>
