[lustre-devel] [PATCH 08/37] lustre: obdclass: don't copy ops structures in to new type.

[James Simmons <jsimmons@infradead.org>]

> The obd_ops and md_ops structures passed to class_register_type() are
> read-only, and have a lifetime that is exceeds the lifetime of the
> obd_type - they are static in a module which unregisters the type before
> being unloaded.
> 
> So there is no need to copy the ops, just store a pointer.
> 
> Also mark all the structures as read-only to confirm they don't get
> written.  This is best-practice for structures of function pointers.

Reviewed-by: James Simmons <jsimmons@infradead.org>
 
> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
>  drivers/staging/lustre/lustre/include/obd.h        |    4 ++--
>  drivers/staging/lustre/lustre/include/obd_class.h  |    3 ++-
>  drivers/staging/lustre/lustre/lmv/lmv_obd.c        |    4 ++--
>  drivers/staging/lustre/lustre/lov/lov_obd.c        |    2 +-
>  drivers/staging/lustre/lustre/mdc/mdc_request.c    |    4 ++--
>  drivers/staging/lustre/lustre/mgc/mgc_request.c    |    2 +-
>  drivers/staging/lustre/lustre/obdclass/genops.c    |   22 +++++---------------
>  .../staging/lustre/lustre/obdecho/echo_client.c    |    2 +-
>  drivers/staging/lustre/lustre/osc/osc_request.c    |    2 +-
>  9 files changed, 18 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/staging/lustre/lustre/include/obd.h b/drivers/staging/lustre/lustre/include/obd.h
> index a67eb9a14879..9cffda3741ce 100644
> --- a/drivers/staging/lustre/lustre/include/obd.h
> +++ b/drivers/staging/lustre/lustre/include/obd.h
> @@ -99,8 +99,8 @@ struct obd_info {
>  };
>  
>  struct obd_type {
> -	struct obd_ops		*typ_dt_ops;
> -	struct md_ops		*typ_md_ops;
> +	const struct obd_ops	*typ_dt_ops;
> +	const struct md_ops	*typ_md_ops;
>  	struct dentry		*typ_debugfs_entry;
>  	refcount_t		 typ_refcnt;
>  	struct lu_device_type	*typ_lu;
> diff --git a/drivers/staging/lustre/lustre/include/obd_class.h b/drivers/staging/lustre/lustre/include/obd_class.h
> index a61c7950393c..7c2e248a8110 100644
> --- a/drivers/staging/lustre/lustre/include/obd_class.h
> +++ b/drivers/staging/lustre/lustre/include/obd_class.h
> @@ -60,7 +60,8 @@ struct lu_device_type;
>  
>  /* genops.c */
>  struct obd_export *class_conn2export(struct lustre_handle *conn);
> -int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
> +int class_register_type(const struct obd_ops *dt_ops,
> +			const struct md_ops *md_ops,
>  			const char *name, struct lu_device_type *ldt);
>  int class_unregister_type(const char *name);
>  
> diff --git a/drivers/staging/lustre/lustre/lmv/lmv_obd.c b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
> index 1c7379b14f8c..35dff0e96bf7 100644
> --- a/drivers/staging/lustre/lustre/lmv/lmv_obd.c
> +++ b/drivers/staging/lustre/lustre/lmv/lmv_obd.c
> @@ -3044,7 +3044,7 @@ static int lmv_merge_attr(struct obd_export *exp,
>  	return 0;
>  }
>  
> -static struct obd_ops lmv_obd_ops = {
> +static const struct obd_ops lmv_obd_ops = {
>  	.owner			= THIS_MODULE,
>  	.setup			= lmv_setup,
>  	.cleanup		= lmv_cleanup,
> @@ -3061,7 +3061,7 @@ static struct obd_ops lmv_obd_ops = {
>  	.quotactl		= lmv_quotactl
>  };
>  
> -static struct md_ops lmv_md_ops = {
> +static const struct md_ops lmv_md_ops = {
>  	.get_root		= lmv_get_root,
>  	.null_inode		= lmv_null_inode,
>  	.close			= lmv_close,
> diff --git a/drivers/staging/lustre/lustre/lov/lov_obd.c b/drivers/staging/lustre/lustre/lov/lov_obd.c
> index fd769c39b482..bad9538706f0 100644
> --- a/drivers/staging/lustre/lustre/lov/lov_obd.c
> +++ b/drivers/staging/lustre/lustre/lov/lov_obd.c
> @@ -1332,7 +1332,7 @@ static int lov_quotactl(struct obd_device *obd, struct obd_export *exp,
>  	return rc;
>  }
>  
> -static struct obd_ops lov_obd_ops = {
> +static const struct obd_ops lov_obd_ops = {
>  	.owner		= THIS_MODULE,
>  	.setup		= lov_setup,
>  	.cleanup	= lov_cleanup,
> diff --git a/drivers/staging/lustre/lustre/mdc/mdc_request.c b/drivers/staging/lustre/lustre/mdc/mdc_request.c
> index db2c045aa1cd..72a5264b2d78 100644
> --- a/drivers/staging/lustre/lustre/mdc/mdc_request.c
> +++ b/drivers/staging/lustre/lustre/mdc/mdc_request.c
> @@ -2569,7 +2569,7 @@ static int mdc_process_config(struct obd_device *obd, u32 len, void *buf)
>  	return count > 0 ? 0 : count;
>  }
>  
> -static struct obd_ops mdc_obd_ops = {
> +static const struct obd_ops mdc_obd_ops = {
>  	.owner			= THIS_MODULE,
>  	.setup			= mdc_setup,
>  	.precleanup		= mdc_precleanup,
> @@ -2591,7 +2591,7 @@ static struct obd_ops mdc_obd_ops = {
>  	.quotactl		= mdc_quotactl,
>  };
>  
> -static struct md_ops mdc_md_ops = {
> +static const struct md_ops mdc_md_ops = {
>  	.get_root		= mdc_get_root,
>  	.null_inode		= mdc_null_inode,
>  	.close			= mdc_close,
> diff --git a/drivers/staging/lustre/lustre/mgc/mgc_request.c b/drivers/staging/lustre/lustre/mgc/mgc_request.c
> index a6ee715921b8..3ff0bf1c4a22 100644
> --- a/drivers/staging/lustre/lustre/mgc/mgc_request.c
> +++ b/drivers/staging/lustre/lustre/mgc/mgc_request.c
> @@ -1817,7 +1817,7 @@ static int mgc_process_config(struct obd_device *obd, u32 len, void *buf)
>  	return rc;
>  }
>  
> -static struct obd_ops mgc_obd_ops = {
> +static const struct obd_ops mgc_obd_ops = {
>  	.owner          = THIS_MODULE,
>  	.setup          = mgc_setup,
>  	.precleanup     = mgc_precleanup,
> diff --git a/drivers/staging/lustre/lustre/obdclass/genops.c b/drivers/staging/lustre/lustre/obdclass/genops.c
> index a3437c2d07bb..d013e9a358f1 100644
> --- a/drivers/staging/lustre/lustre/obdclass/genops.c
> +++ b/drivers/staging/lustre/lustre/obdclass/genops.c
> @@ -142,8 +142,6 @@ static void class_sysfs_release(struct kobject *kobj)
>  	if (type->typ_lu)
>  		lu_device_type_fini(type->typ_lu);
>  
> -	kfree(type->typ_md_ops);
> -	kfree(type->typ_dt_ops);
>  	kfree(type);
>  }
>  
> @@ -154,7 +152,8 @@ static struct kobj_type class_ktype = {
>  
>  #define CLASS_MAX_NAME 1024
>  
> -int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
> +int class_register_type(const struct obd_ops *dt_ops,
> +			const struct md_ops *md_ops,
>  			const char *name,
>  			struct lu_device_type *ldt)
>  {
> @@ -179,17 +178,8 @@ int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
>  	type->typ_kobj.kset = lustre_kset;
>  	kobject_init(&type->typ_kobj, &class_ktype);
>  
> -	type->typ_dt_ops = kzalloc(sizeof(*type->typ_dt_ops), GFP_NOFS);
> -	type->typ_md_ops = kzalloc(sizeof(*type->typ_md_ops), GFP_NOFS);
> -
> -	if (!type->typ_dt_ops ||
> -	    !type->typ_md_ops)
> -		goto failed;
> -
> -	*type->typ_dt_ops = *dt_ops;
> -	/* md_ops is optional */
> -	if (md_ops)
> -		*type->typ_md_ops = *md_ops;
> +	type->typ_dt_ops = dt_ops;
> +	type->typ_md_ops = md_ops;
>  
>  	rc = kobject_add(&type->typ_kobj, &lustre_kset->kobj, "%s", name);
>  	if (rc)
> @@ -227,8 +217,8 @@ int class_unregister_type(const char *name)
>  		CERROR("type %s has refcount (%d)\n", name, refcount_read(&type->typ_refcnt));
>  		/* This is a bad situation, let's make the best of it */
>  		/* Remove ops, but leave the name for debugging */
> -		kfree(type->typ_dt_ops);
> -		kfree(type->typ_md_ops);
> +		type->typ_dt_ops = NULL;
> +		type->typ_md_ops = NULL;
>  		kobject_put(&type->typ_kobj);
>  		return -EBUSY;
>  	}
> diff --git a/drivers/staging/lustre/lustre/obdecho/echo_client.c b/drivers/staging/lustre/lustre/obdecho/echo_client.c
> index 317123fd27cb..baf34c85c4b5 100644
> --- a/drivers/staging/lustre/lustre/obdecho/echo_client.c
> +++ b/drivers/staging/lustre/lustre/obdecho/echo_client.c
> @@ -1676,7 +1676,7 @@ static int echo_client_disconnect(struct obd_export *exp)
>  	return rc;
>  }
>  
> -static struct obd_ops echo_client_obd_ops = {
> +static const struct obd_ops echo_client_obd_ops = {
>  	.owner			= THIS_MODULE,
>  	.iocontrol		= echo_client_iocontrol,
>  	.connect		= echo_client_connect,
> diff --git a/drivers/staging/lustre/lustre/osc/osc_request.c b/drivers/staging/lustre/lustre/osc/osc_request.c
> index 3fedfaf249c4..442b4355d946 100644
> --- a/drivers/staging/lustre/lustre/osc/osc_request.c
> +++ b/drivers/staging/lustre/lustre/osc/osc_request.c
> @@ -2988,7 +2988,7 @@ static int osc_process_config(struct obd_device *obd, u32 len, void *buf)
>  	return osc_process_config_base(obd, buf);
>  }
>  
> -static struct obd_ops osc_obd_ops = {
> +static const struct obd_ops osc_obd_ops = {
>  	.owner          = THIS_MODULE,
>  	.setup          = osc_setup,
>  	.precleanup     = osc_precleanup,
> 
> 
>