On Mon, Jul 13, 2020 at 06:54:22PM +0300, Oded Gabbay wrote: > From: Ofir Bitton <[email protected]> > > Instead of using standard dma-fence mechanism designed for GPU's, we > introduce our own implementation based on the former one. This > implementation is much more sparse than the original, contains only > mandatory functionality required by the driver.
Sad you can't use the in-kernel code for this, I really don't understand what's wrong with using it as-is. Daniel, why do we need/want duplicate code floating around in the tree like this? Copying code leads to errors, here's some documentation ones: > --- /dev/null > +++ b/drivers/misc/habanalabs/hl_dma_fence.c > @@ -0,0 +1,338 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Fence mechanism for dma-buf and to allow for asynchronous dma access Is that what this still does? > + * > + * Copyright (C) 2012 Canonical Ltd > + * Copyright (C) 2012 Texas Instruments > + * > + * Authors: > + * Rob Clark <[email protected]> > + * Maarten Lankhorst <[email protected]> > + * > + * The dma_fence module is a copy of dma-fence at drivers/dma-buf. "The hl_dma_fence" module... And is it a stand-alone module? Or just a single file? > + * This was done due to an explicit request by GPU developers who asked not > + * to use the dma-buf module because we aren't part of DRM subsystem. Why is dma-buf only for use for DRM? If it is, should the symbol namespace be set to that to catch users that want to use it for their own code? > + * This copy was stripped from all extra features that habanalabs driver > + * doesn't use, including the uapi interface dma-buf exposes. > + * In addition, we removed the callbacks because the only usage is from > inside > + * habanalabs driver > + */ > + > +#include "hl_dma_fence.h" > +#include "habanalabs.h" > +#include <linux/slab.h> > +#include <linux/export.h> > +#include <linux/atomic.h> > +#include <linux/sched/signal.h> > + > +/** > + * DOC: DMA fences overview > + * > + * DMA fences, represented by &struct hl_dma_fence, are the kernel internal > + * synchronization primitive for DMA operations like GPU rendering, video > + * encoding/decoding, or displaying buffers on a screen. I don't think this is correct anymore, right? :( > --- /dev/null > +++ b/drivers/misc/habanalabs/hl_dma_fence.h > @@ -0,0 +1,148 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * Fence mechanism for dma-buf to allow for asynchronous dma access > + * > + * Copyright (C) 2012 Canonical Ltd > + * Copyright (C) 2012 Texas Instruments > + * > + * Authors: > + * Rob Clark <[email protected]> > + * Maarten Lankhorst <[email protected]> > + * > + * The dma_fence module is a copy of dma-fence at drivers/dma-buf. Same comments here for the .h file. thanks, greg k-h
