linux-kernel - Re: [PATCH v2] device-dax: Auto-bind device after successful new

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Date:   Wed, 13 Feb 2019 09:06:16 +0100
From:   Brice Goglin <Brice.Goglin@...ia.fr>
To:     Dan Williams <dan.j.williams@...el.com>, linux-nvdimm@...ts.01.org
Cc:     Alexander Duyck <alexander.h.duyck@...ux.intel.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] device-dax: Auto-bind device after successful new_id

Thanks Dan, remove_id works now.

Brice


Le 13/02/2019 à 02:50, Dan Williams a écrit :
> The typical 'new_id' attribute behavior is to immediately attach a
> device to its driver after a new device-id is added. Implement this
> behavior for the dax bus.
>
> Reported-by: Alexander Duyck <alexander.h.duyck@...ux.intel.com>
> Reported-by: Brice Goglin <Brice.Goglin@...ia.fr>
> Cc: Dave Hansen <dave.hansen@...ux.intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>
> ---
> Changes since v1:
> * Fix the remove_id path since do_id_store() is shared with the new_id
>   path (Brice)
>
> Brice, this works for me. I'll push it out on libnvdimm-pending, or in
> the meantime you can apply this patch after reverting commit
> a9f1ffdb6a20 on the current state of the branch.
>
>  drivers/dax/bus.c |   24 ++++++++++++++++++------
>  1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
> index c620ad52d7e5..a410154d75fb 100644
> --- a/drivers/dax/bus.c
> +++ b/drivers/dax/bus.c
> @@ -57,8 +57,13 @@ static int dax_match_id(struct dax_device_driver *dax_drv, struct device *dev)
>  	return match;
>  }
>  
> +enum id_action {
> +	ID_REMOVE,
> +	ID_ADD,
> +};
> +
>  static ssize_t do_id_store(struct device_driver *drv, const char *buf,
> -		size_t count, bool add)
> +		size_t count, enum id_action action)
>  {
>  	struct dax_device_driver *dax_drv = to_dax_drv(drv);
>  	unsigned int region_id, id;
> @@ -77,7 +82,7 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf,
>  	mutex_lock(&dax_bus_lock);
>  	dax_id = __dax_match_id(dax_drv, buf);
>  	if (!dax_id) {
> -		if (add) {
> +		if (action == ID_ADD) {
>  			dax_id = kzalloc(sizeof(*dax_id), GFP_KERNEL);
>  			if (dax_id) {
>  				strncpy(dax_id->dev_name, buf, DAX_NAME_LEN);
> @@ -86,26 +91,33 @@ static ssize_t do_id_store(struct device_driver *drv, const char *buf,
>  				rc = -ENOMEM;
>  		} else
>  			/* nothing to remove */;
> -	} else if (!add) {
> +	} else if (action == ID_REMOVE) {
>  		list_del(&dax_id->list);
>  		kfree(dax_id);
>  	} else
>  		/* dax_id already added */;
>  	mutex_unlock(&dax_bus_lock);
> -	return rc;
> +
> +	if (rc < 0)
> +		return rc;
> +	if (action == ID_ADD)
> +		rc = driver_attach(drv);
> +	if (rc)
> +		return rc;
> +	return count;
>  }
>  
>  static ssize_t new_id_store(struct device_driver *drv, const char *buf,
>  		size_t count)
>  {
> -	return do_id_store(drv, buf, count, true);
> +	return do_id_store(drv, buf, count, ID_ADD);
>  }
>  static DRIVER_ATTR_WO(new_id);
>  
>  static ssize_t remove_id_store(struct device_driver *drv, const char *buf,
>  		size_t count)
>  {
> -	return do_id_store(drv, buf, count, false);
> +	return do_id_store(drv, buf, count, ID_REMOVE);
>  }
>  static DRIVER_ATTR_WO(remove_id);
>  
>