linux-kernel - Re: [RESEND][PATCH v8 2/5] dma-buf: heaps: Add heap helpers

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Message-ID: <20190923220849.ttwmt2xohptzznme@DESKTOP-E1NTVVP.localdomain>
Date:   Mon, 23 Sep 2019 22:08:55 +0000
From:   Brian Starkey <Brian.Starkey@....com>
To:     John Stultz <john.stultz@...aro.org>
CC:     lkml <linux-kernel@...r.kernel.org>,
        Laura Abbott <labbott@...hat.com>,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        Sumit Semwal <sumit.semwal@...aro.org>,
        Liam Mark <lmark@...eaurora.org>,
        Pratik Patel <pratikp@...eaurora.org>,
        Vincent Donnefort <Vincent.Donnefort@....com>,
        Sudipto Paul <Sudipto.Paul@....com>,
        "Andrew F . Davis" <afd@...com>,
        Christoph Hellwig <hch@...radead.org>,
        Chenbo Feng <fengc@...gle.com>,
        Alistair Strachan <astrachan@...gle.com>,
        Hridya Valsaraju <hridya@...gle.com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        nd <nd@....com>
Subject: Re: [RESEND][PATCH v8 2/5] dma-buf: heaps: Add heap helpers

Hi John,

On Fri, Sep 06, 2019 at 06:47:09PM +0000, John Stultz wrote:
> Add generic helper dmabuf ops for dma heaps, so we can reduce
> the amount of duplicative code for the exported dmabufs.
> 
> This code is an evolution of the Android ION implementation, so
> thanks to its original authors and maintainters:
>   Rebecca Schultz Zavin, Colin Cross, Laura Abbott, and others!
> 
> Cc: Laura Abbott <labbott@...hat.com>
> Cc: Benjamin Gaignard <benjamin.gaignard@...aro.org>
> Cc: Sumit Semwal <sumit.semwal@...aro.org>
> Cc: Liam Mark <lmark@...eaurora.org>
> Cc: Pratik Patel <pratikp@...eaurora.org>
> Cc: Brian Starkey <Brian.Starkey@....com>
> Cc: Vincent Donnefort <Vincent.Donnefort@....com>
> Cc: Sudipto Paul <Sudipto.Paul@....com>
> Cc: Andrew F. Davis <afd@...com>
> Cc: Christoph Hellwig <hch@...radead.org>
> Cc: Chenbo Feng <fengc@...gle.com>
> Cc: Alistair Strachan <astrachan@...gle.com>
> Cc: Hridya Valsaraju <hridya@...gle.com>
> Cc: dri-devel@...ts.freedesktop.org
> Reviewed-by: Benjamin Gaignard <benjamin.gaignard@...aro.org>
> Signed-off-by: John Stultz <john.stultz@...aro.org>

Two minor things below.

> ---
> v2:
> * Removed cache management performance hack that I had
>   accidentally folded in.
> * Removed stats code that was in helpers
> * Lots of checkpatch cleanups
> v3:
> * Uninline INIT_HEAP_HELPER_BUFFER (suggested by Christoph)
> * Switch to WARN on buffer destroy failure (suggested by Brian)
> * buffer->kmap_cnt decrementing cleanup (suggested by Christoph)
> * Extra buffer->vaddr checking in dma_heap_dma_buf_kmap
>   (suggested by Brian)
> * Switch to_helper_buffer from macro to inline function
>   (suggested by Benjamin)
> * Rename kmap->vmap (folded in from Andrew)
> * Use vmap for vmapping - not begin_cpu_access (folded in from
>   Andrew)
> * Drop kmap for now, as its optional (folded in from Andrew)
> * Fold dma_heap_map_user into the single caller (foled in from
>   Andrew)
> * Folded in patch from Andrew to track page list per heap not
>   sglist, which simplifies the tracking logic
> v4:
> * Moved dma-heap.h change out to previous patch
> v6:
> * Minor cleanups and typo fixes suggested by Brian
> v7:
> * Removed stray ;
> * Make init_heap_helper_buffer lowercase, as suggested by Christoph
> * Add dmabuf export helper to reduce boilerplate code
> v8:
> * Remove unused private_flags value
> * Condense dma_heap_buffer and heap_helper_buffer (suggested by
>   Christoph)
> * Fix indentation by using shorter argument names (suggested by
>   Christoph)
> * Add flush_kernel_vmap_range/invalidate_kernel_vmap_range calls
>   (suggested by Christoph)
> * Checkpatch whitespace fixups
> ---

...

> +
> +static void *dma_heap_buffer_vmap_get(struct heap_helper_buffer *buffer)
> +{
> +	void *vaddr;
> +
> +	if (buffer->vmap_cnt) {
> +		buffer->vmap_cnt++;
> +		return buffer->vaddr;
> +	}
> +	vaddr = dma_heap_map_kernel(buffer);
> +	if (WARN_ONCE(!vaddr,
> +		      "heap->ops->map_kernel should return ERR_PTR on error"))

Looks like the message is out-of-date here.

...

> +
> +/**
> + * struct heap_helper_buffer - helper buffer metadata
> + * @heap:		back pointer to the heap the buffer came from
> + * @dmabuf:		backing dma-buf for this buffer
> + * @size:		size of the buffer
> + * @flags:		buffer specific flags
> + * @priv_virt		pointer to heap specific private value
> + * @lock		mutext to protect the data in this structure
> + * @vmap_cnt		count of vmap references on the buffer
> + * @vaddr		vmap'ed virtual address
> + * @pagecount		number of pages in the buffer
> + * @pages		list of page pointers
> + * @attachment		list of device attachments

s/attachment/attachments/

With those fixed, feel free to add:

Reviewed-by: Brian Starkey <brian.starkey@....com>

Thanks,
-Brian