[PATCH WW 01/13] reservation: cross-device reservation support, v4

[Jerome Glisse]

On Thu, Jun 27, 2013 at 01:48:16PM +0200, Maarten Lankhorst wrote:
> This adds support for a generic reservations framework that can be
> hooked up to ttm and dma-buf and allows easy sharing of reservations
> across devices.
> 
> The idea is that a dma-buf and ttm object both will get a pointer
> to a struct reservation_object, which has to be reserved before
> anything is done with the contents of the dma-buf.
> 
> Changes since v1:
>  - Fix locking issue in ticket_reserve, which could cause mutex_unlock
>    to be called too many times.
> Changes since v2:
>  - All fence related calls and members have been taken out for now,
>    what's left is the bare minimum to be useful for ttm locking conversion.
> Changes since v3:
>  - Removed helper functions too. The documentation has an example
>    implementation for locking. With the move to ww_mutex there is no
>    need to have much logic any more.
> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>

Reviewed-by: Jerome Glisse <jglisse at redhat.com>

> ---
>  Documentation/DocBook/device-drivers.tmpl |  2 +
>  drivers/base/Makefile                     |  2 +-
>  drivers/base/reservation.c                | 39 +++++++++++++++++++
>  include/linux/reservation.h               | 62 +++++++++++++++++++++++++++++++
>  4 files changed, 104 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/base/reservation.c
>  create mode 100644 include/linux/reservation.h
> 
> diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl
> index c36892c..f0648a8 100644
> --- a/Documentation/DocBook/device-drivers.tmpl
> +++ b/Documentation/DocBook/device-drivers.tmpl
> @@ -126,6 +126,8 @@ X!Edrivers/base/interface.c
>       </sect1>
>       <sect1><title>Device Drivers DMA Management</title>
>  !Edrivers/base/dma-buf.c
> +!Edrivers/base/reservation.c
> +!Iinclude/linux/reservation.h
>  !Edrivers/base/dma-coherent.c
>  !Edrivers/base/dma-mapping.c
>       </sect1>
> diff --git a/drivers/base/Makefile b/drivers/base/Makefile
> index 4e22ce3..48029aa 100644
> --- a/drivers/base/Makefile
> +++ b/drivers/base/Makefile
> @@ -10,7 +10,7 @@ obj-$(CONFIG_CMA) += dma-contiguous.o
>  obj-y			+= power/
>  obj-$(CONFIG_HAS_DMA)	+= dma-mapping.o
>  obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
> -obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf.o
> +obj-$(CONFIG_DMA_SHARED_BUFFER) += dma-buf.o reservation.o
>  obj-$(CONFIG_ISA)	+= isa.o
>  obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
>  obj-$(CONFIG_NUMA)	+= node.o
> diff --git a/drivers/base/reservation.c b/drivers/base/reservation.c
> new file mode 100644
> index 0000000..a73fbf3
> --- /dev/null
> +++ b/drivers/base/reservation.c
> @@ -0,0 +1,39 @@
> +/*
> + * Copyright (C) 2012-2013 Canonical Ltd
> + *
> + * Based on bo.c which bears the following copyright notice,
> + * but is dual licensed:
> + *
> + * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
> + * All Rights Reserved.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the
> + * "Software"), to deal in the Software without restriction, including
> + * without limitation the rights to use, copy, modify, merge, publish,
> + * distribute, sub license, and/or sell copies of the Software, and to
> + * permit persons to whom the Software is furnished to do so, subject to
> + * the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the
> + * next paragraph) shall be included in all copies or substantial portions
> + * of the Software.
> + *
> + * 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 NON-INFRINGEMENT. IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
> + *
> + **************************************************************************/
> +/*
> + * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
> + */
> +
> +#include <linux/reservation.h>
> +#include <linux/export.h>
> +
> +DEFINE_WW_CLASS(reservation_ww_class);
> +EXPORT_SYMBOL(reservation_ww_class);
> diff --git a/include/linux/reservation.h b/include/linux/reservation.h
> new file mode 100644
> index 0000000..e9ee806
> --- /dev/null
> +++ b/include/linux/reservation.h
> @@ -0,0 +1,62 @@
> +/*
> + * Header file for reservations for dma-buf and ttm
> + *
> + * Copyright(C) 2011 Linaro Limited. All rights reserved.
> + * Copyright (C) 2012-2013 Canonical Ltd
> + * Copyright (C) 2012 Texas Instruments
> + *
> + * Authors:
> + * Rob Clark <rob.clark at linaro.org>
> + * Maarten Lankhorst <maarten.lankhorst at canonical.com>
> + * Thomas Hellstrom <thellstrom-at-vmware-dot-com>
> + *
> + * Based on bo.c which bears the following copyright notice,
> + * but is dual licensed:
> + *
> + * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
> + * All Rights Reserved.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the
> + * "Software"), to deal in the Software without restriction, including
> + * without limitation the rights to use, copy, modify, merge, publish,
> + * distribute, sub license, and/or sell copies of the Software, and to
> + * permit persons to whom the Software is furnished to do so, subject to
> + * the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the
> + * next paragraph) shall be included in all copies or substantial portions
> + * of the Software.
> + *
> + * 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 NON-INFRINGEMENT. IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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 _LINUX_RESERVATION_H
> +#define _LINUX_RESERVATION_H
> +
> +#include <linux/mutex.h>
> +
> +extern struct ww_class reservation_ww_class;
> +
> +struct reservation_object {
> +	struct ww_mutex lock;
> +};
> +
> +static inline void
> +reservation_object_init(struct reservation_object *obj)
> +{
> +	ww_mutex_init(&obj->lock, &reservation_ww_class);
> +}
> +
> +static inline void
> +reservation_object_fini(struct reservation_object *obj)
> +{
> +	ww_mutex_destroy(&obj->lock);
> +}
> +
> +#endif /* _LINUX_RESERVATION_H */
> -- 
> 1.8.3.1
> 
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