Re: [PATCH RFC 01/10] IB/core: Add a generic way to execute an operation on a uobject

[Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>]

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On Wed, Apr 19, 2017 at 06:20:16PM +0300, Matan Barak wrote:
> The ioctl infrastructure treats all user-objects in the same manner.
> It gets an id from the user-space and by using the object type and
> operation mentioned in the action specification, it executes this
> operation. An operation is split to two stages. The first one is
> carried out before executing the handler and the second one is
> executed afterwards.
>
> In order to abstract these details from the ioctl infrastructure
> layer, we add uverbs_get_uobject_from_context and
> uverbs_finalize_object functions which corresponds to the first
> and second stages respectively.
>
> Signed-off-by: Matan Barak <matanb-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>
> ---
>  drivers/infiniband/core/rdma_core.c | 51 ++++++++++++++++++++++++++++++++++++
>  drivers/infiniband/core/rdma_core.h | 16 ++++++++++++
>  include/rdma/uverbs_ioctl.h         | 52 +++++++++++++++++++++++++++++++++++++
>  3 files changed, 119 insertions(+)
>  create mode 100644 include/rdma/uverbs_ioctl.h
>
> diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c
> index 41c31a2..269fa7f 100644
> --- a/drivers/infiniband/core/rdma_core.c
> +++ b/drivers/infiniband/core/rdma_core.c
> @@ -35,6 +35,7 @@
>  #include <rdma/ib_verbs.h>
>  #include <rdma/uverbs_types.h>
>  #include <linux/rcupdate.h>
> +#include <rdma/uverbs_ioctl.h>
>  #include "uverbs.h"
>  #include "core_priv.h"
>  #include "rdma_core.h"
> @@ -625,3 +626,53 @@ void uverbs_initialize_ucontext(struct ib_ucontext *ucontext)
>  	.needs_kfree_rcu = false,
>  };
>
> +struct ib_uobject *uverbs_get_uobject_from_context(const struct uverbs_obj_type *type_attrs,
> +						   struct ib_ucontext *ucontext,
> +						   enum uverbs_idr_access access,
> +						   int id)
> +{
> +	switch (access) {
> +	case UVERBS_ACCESS_READ:
> +		return rdma_lookup_get_uobject(type_attrs, ucontext, id, false);
> +	case UVERBS_ACCESS_DESTROY:
> +	case UVERBS_ACCESS_WRITE:
> +		return rdma_lookup_get_uobject(type_attrs, ucontext, id, true);
> +	case UVERBS_ACCESS_NEW:
> +		return rdma_alloc_begin_uobject(type_attrs, ucontext);
> +	default:
> +		WARN_ON(true);
> +		return ERR_PTR(-EOPNOTSUPP);
> +	}
> +}
> +
> +int uverbs_finalize_object(struct ib_uobject *uobj,
> +			   enum uverbs_idr_access access,
> +			   bool commit)
> +{
> +	int ret = 0;
> +
> +	switch (access) {
> +	case UVERBS_ACCESS_READ:
> +		rdma_lookup_put_uobject(uobj, false);
> +		break;
> +	case UVERBS_ACCESS_WRITE:
> +		rdma_lookup_put_uobject(uobj, true);
> +		break;
> +	case UVERBS_ACCESS_DESTROY:
> +		if (commit)
> +			ret = rdma_remove_commit_uobject(uobj);
> +		else
> +			rdma_lookup_put_uobject(uobj, true);
> +		break;
> +	case UVERBS_ACCESS_NEW:
> +		if (commit)
> +			ret = rdma_alloc_commit_uobject(uobj);
> +		else
> +			rdma_alloc_abort_uobject(uobj);
> +		break;
> +	default:
> +		WARN_ON(true);
> +	}
> +
> +	return ret;
> +}
> diff --git a/drivers/infiniband/core/rdma_core.h b/drivers/infiniband/core/rdma_core.h
> index 1b82e7f..5a1da24 100644
> --- a/drivers/infiniband/core/rdma_core.h
> +++ b/drivers/infiniband/core/rdma_core.h
> @@ -39,6 +39,7 @@
>
>  #include <linux/idr.h>
>  #include <rdma/uverbs_types.h>
> +#include <rdma/uverbs_ioctl.h>
>  #include <rdma/ib_verbs.h>
>  #include <linux/mutex.h>
>
> @@ -75,4 +76,19 @@
>   */
>  void uverbs_close_fd(struct file *f);
>
> +/*
> + * Get an ib_uobject that corresponds to the given id from ucontext, assuming
> + * the object is from the given type. Lock it to the required access.
> + * This function could create (access == NEW) or destroy (access == DESTROY)
> + * objects if required. The action will be finalized only when
> + * uverbs_finalize_object is called.
> + */
> +struct ib_uobject *uverbs_get_uobject_from_context(const struct uverbs_obj_type *type_attrs,
> +						   struct ib_ucontext *ucontext,
> +						   enum uverbs_idr_access access,
> +						   int id);
> +int uverbs_finalize_object(struct ib_uobject *uobj,
> +			   enum uverbs_idr_access access,
> +			   bool commit);
> +
>  #endif /* RDMA_CORE_H */
> diff --git a/include/rdma/uverbs_ioctl.h b/include/rdma/uverbs_ioctl.h
> new file mode 100644
> index 0000000..a18468e
> --- /dev/null
> +++ b/include/rdma/uverbs_ioctl.h
> @@ -0,0 +1,52 @@
> +/*
> + * Copyright (c) 2016, Mellanox Technologies inc.  All rights reserved.
> + *
> + * This software is available to you under a choice of one of two
> + * licenses.  You may choose to be licensed under the terms of the GNU
> + * General Public License (GPL) Version 2, available from the file
> + * COPYING in the main directory of this source tree, or the
> + * OpenIB.org BSD license below:
> + *
> + *     Redistribution and use in source and binary forms, with or
> + *     without modification, are permitted provided that the following
> + *     conditions are met:
> + *
> + *      - Redistributions of source code must retain the above
> + *        copyright notice, this list of conditions and the following
> + *        disclaimer.
> + *
> + *      - Redistributions in binary form must reproduce the above
> + *        copyright notice, this list of conditions and the following
> + *        disclaimer in the documentation and/or other materials
> + *        provided with the distribution.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
> + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
> + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
> + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
> + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
> + * SOFTWARE.
> + */
> +
> +#ifndef _UVERBS_IOCTL_
> +#define _UVERBS_IOCTL_
> +
> +#include <rdma/uverbs_types.h>
> +
> +/*
> + * =======================================
> + *	Verbs action specifications
> + * =======================================
> + */
> +
> +enum uverbs_idr_access {
> +	UVERBS_ACCESS_READ,
> +	UVERBS_ACCESS_WRITE,
> +	UVERBS_ACCESS_NEW,
> +	UVERBS_ACCESS_DESTROY
> +};

Does it make sense to have MODIFY too?

> +
> +#endif
> +
> --
> 1.8.3.1
>
> --
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