linux-kernel - Re: [PATCH 2/3] dma-buf/heaps: replace kmap_atomic with kmap_local

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Message-ID: <CABdmKX2xEn8QjObqR3VNb=RqMZVNBiNtkfYWm8h_3Xc8KMkdag@mail.gmail.com>
Date: Tue, 1 Oct 2024 23:24:03 +0200
From: "T.J. Mercier" <tjmercier@...gle.com>
To: Pintu Kumar <quic_pintu@...cinc.com>
Cc: sumit.semwal@...aro.org, benjamin.gaignard@...labora.com, 
	Brian.Starkey@....com, jstultz@...gle.com, christian.koenig@....com, 
	linux-media@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
	linaro-mm-sig@...ts.linaro.org, linux-kernel@...r.kernel.org, joe@...ches.com, 
	skhan@...uxfoundation.org, pintu.ping@...il.com
Subject: Re: [PATCH 2/3] dma-buf/heaps: replace kmap_atomic with kmap_local_page

On Tue, Oct 1, 2024 at 7:51 PM Pintu Kumar <quic_pintu@...cinc.com> wrote:
>
> Use of kmap_atomic/kunmap_atomic is deprecated, use
> kmap_local_page/kunmap_local instead.
>
> This is reported by checkpatch.
> Also fix repeated word issue.
>
> WARNING: Deprecated use of 'kmap_atomic', prefer 'kmap_local_page' instead
> +                       void *vaddr = kmap_atomic(page);
>
> WARNING: Deprecated use of 'kunmap_atomic', prefer 'kunmap_local' instead
> +                       kunmap_atomic(vaddr);
>
> WARNING: Possible repeated word: 'by'
> +                        * has been killed by by SIGKILL
>
> total: 0 errors, 3 warnings, 405 lines checked
>
> Signed-off-by: Pintu Kumar <quic_pintu@...cinc.com>

Reviewed-by: T.J. Mercier <tjmercier@...gle.com>

The Android kernels have been doing this for over a year, so should be
pretty well tested at this point:
https://r.android.com/c/kernel/common/+/2500840

> ---
>  drivers/dma-buf/heaps/cma_heap.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c
> index 93be88b805fe..8c55431cc16c 100644
> --- a/drivers/dma-buf/heaps/cma_heap.c
> +++ b/drivers/dma-buf/heaps/cma_heap.c
> @@ -309,13 +309,13 @@ static struct dma_buf *cma_heap_allocate(struct dma_heap *heap,
>                 struct page *page = cma_pages;
>
>                 while (nr_clear_pages > 0) {
> -                       void *vaddr = kmap_atomic(page);
> +                       void *vaddr = kmap_local_page(page);
>
>                         memset(vaddr, 0, PAGE_SIZE);
> -                       kunmap_atomic(vaddr);
> +                       kunmap_local(vaddr);
>                         /*
>                          * Avoid wasting time zeroing memory if the process
> -                        * has been killed by by SIGKILL
> +                        * has been killed by SIGKILL.
>                          */
>                         if (fatal_signal_pending(current))
>                                 goto free_cma;
> --
> 2.17.1
>