Re: [PATCH 2/3] mmc: Export ios settings for a host through debugfs

From: Pierre Ossman
Date: Sat Jun 28 2008 - 09:34:26 EST


On Thu, 26 Jun 2008 13:09:48 +0200
Haavard Skinnemoen <haavard.skinnemoen@xxxxxxxxx> wrote:

> From: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
>
> Export all the fields in struct mmc_ios under /sys/kernel/debug/<host>/ios
>
> Signed-off-by: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
> ---
> drivers/mmc/core/host.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/mmc/host.h | 13 +++++++++++
> 2 files changed, 68 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 93da502..2977f26 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -25,6 +25,54 @@
> #ifdef CONFIG_MMC_DEBUG_FS
> #include <linux/debugfs.h>
>
> +static void mmc_remove_ios_debugfs(struct mmc_ios *ios)
> +{
> + if (ios->dbg_root) {

You can save a bit of indentation if you do:

if (!ios->dbg_root)
return;

> +static int mmc_add_ios_debugfs(struct mmc_ios *ios, struct dentry *parent)
> +{
> + struct dentry *dir;
> +
> + dir = debugfs_create_dir("ios", parent);
> + if (!dir)
> + return -EBUSY; /* or whatever */

Is it undefined what a NULL return means here? I would have expected an
ERRPTR or ENOMEM.

> +#ifdef CONFIG_MMC_DEBUG_FS
> + struct dentry *dbg_root;
> + struct dentry *dbg_clock;
> + struct dentry *dbg_vdd;
> + struct dentry *dbg_bus_mode;
> + struct dentry *dbg_chip_select;
> + struct dentry *dbg_power_mode;
> + struct dentry *dbg_bus_width;
> + struct dentry *dbg_timing;
> +#endif

Can't we use debugfs' own bookkeeping to keep track of them? Saves us a
lot of noise in these structures.

--
-- Pierre Ossman

Linux kernel, MMC maintainer http://www.kernel.org
rdesktop, core developer http://www.rdesktop.org

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