[PATCH 01/15] drm/tegra: Map cmdbuf once for reloc processing

[Thierry Reding]

On Mon, Nov 18, 2019 at 11:35:22AM +0100, Daniel Vetter wrote:
> A few reasons to drop kmap:
> 
> - For native objects all we do is look at obj->vaddr anyway, so might
>   as well not call functions for every page.
> 
> - Reloc-processing on dma-buf is ... questionable.
> 
> - Plus most dma-buf that bother kernel cpu mmaps give you at least
>   vmap, much less kmaps. And all the ones relevant for arm-soc are
>   again doing a obj->vaddr game anyway, there's no real kmap going on
>   on arm it seems.
> 
> Plus this seems to be the only real in-tree user of dma_buf_kmap, and
> I'd like to get rid of that.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> Cc: Thierry Reding <thierry.reding at gmail.com>
> Cc: linux-tegra at vger.kernel.org
> ---
>  drivers/gpu/host1x/job.c | 21 +++++++--------------
>  1 file changed, 7 insertions(+), 14 deletions(-)

This looks correct to me, and running some of the grate project's tests
against this works just fine, so:

Reviewed-by: Thierry Reding <treding at nvidia.com>
Tested-by: Thierry Reding <treding at nvidia.com>

> diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
> index 25ca54de8fc5..60b2fedd0061 100644
> --- a/drivers/gpu/host1x/job.c
> +++ b/drivers/gpu/host1x/job.c
> @@ -244,8 +244,7 @@ static unsigned int pin_job(struct host1x *host, struct host1x_job *job)
>  
>  static int do_relocs(struct host1x_job *job, struct host1x_job_gather *g)
>  {
> -	u32 last_page = ~0;
> -	void *cmdbuf_page_addr = NULL;
> +	void *cmdbuf_addr = NULL;
>  	struct host1x_bo *cmdbuf = g->bo;
>  	unsigned int i;
>  
> @@ -267,28 +266,22 @@ static int do_relocs(struct host1x_job *job, struct host1x_job_gather *g)
>  			goto patch_reloc;
>  		}
>  
> -		if (last_page != reloc->cmdbuf.offset >> PAGE_SHIFT) {
> -			if (cmdbuf_page_addr)
> -				host1x_bo_kunmap(cmdbuf, last_page,
> -						 cmdbuf_page_addr);
> +		if (!cmdbuf_addr) {
> +			cmdbuf_addr = host1x_bo_mmap(cmdbuf);
>  
> -			cmdbuf_page_addr = host1x_bo_kmap(cmdbuf,
> -					reloc->cmdbuf.offset >> PAGE_SHIFT);
> -			last_page = reloc->cmdbuf.offset >> PAGE_SHIFT;
> -
> -			if (unlikely(!cmdbuf_page_addr)) {
> +			if (unlikely(!cmdbuf_addr)) {
>  				pr_err("Could not map cmdbuf for relocation\n");
>  				return -ENOMEM;
>  			}
>  		}
>  
> -		target = cmdbuf_page_addr + (reloc->cmdbuf.offset & ~PAGE_MASK);
> +		target = cmdbuf_addr + reloc->cmdbuf.offset;
>  patch_reloc:
>  		*target = reloc_addr;
>  	}
>  
> -	if (cmdbuf_page_addr)
> -		host1x_bo_kunmap(cmdbuf, last_page, cmdbuf_page_addr);
> +	if (cmdbuf_addr)
> +		host1x_bo_munmap(cmdbuf, cmdbuf_addr);
>  
>  	return 0;
>  }
> -- 
> 2.24.0
> 
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