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References: <20231207172010.1441468-1-aleksander.lobakin@intel.com> <20231207172010.1441468-7-aleksander.lobakin@intel.com>
In-Reply-To: <20231207172010.1441468-7-aleksander.lobakin@intel.com>
From:   Ilias Apalodimas <ilias.apalodimas@linaro.org>
Date:   Tue, 12 Dec 2023 18:14:09 +0200
Message-ID: <CAC_iWjKD4dq_YdhgOzSfgSX=tmu0ofD-2fCijfTinOq7heYitA@mail.gmail.com>
Subject: Re: [PATCH net-next v6 06/12] page_pool: constify some read-only
 function arguments
To:     Alexander Lobakin <aleksander.lobakin@intel.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
        Michal Kubiak <michal.kubiak@intel.com>,
        Larysa Zaremba <larysa.zaremba@intel.com>,
        Alexander Duyck <alexanderduyck@fb.com>,
        Yunsheng Lin <linyunsheng@huawei.com>,
        David Christensen <drc@linux.vnet.ibm.com>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        Paul Menzel <pmenzel@molgen.mpg.de>, netdev@vger.kernel.org,
        intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org
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On Thu, 7 Dec 2023 at 19:22, Alexander Lobakin
<aleksander.lobakin@intel.com> wrote:
>
> There are several functions taking pointers to data they don't modify.
> This includes statistics fetching, page and page_pool parameters, etc.
> Constify the pointers, so that call sites will be able to pass const
> pointers as well.
> No functional changes, no visible changes in functions sizes.
>
> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
> ---
>  include/net/page_pool/helpers.h | 10 +++++-----
>  net/core/page_pool.c            |  8 ++++----
>  2 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h
> index 7dc65774cde5..c860fad50d00 100644
> --- a/include/net/page_pool/helpers.h
> +++ b/include/net/page_pool/helpers.h
> @@ -58,7 +58,7 @@
>  /* Deprecated driver-facing API, use netlink instead */
>  int page_pool_ethtool_stats_get_count(void);
>  u8 *page_pool_ethtool_stats_get_strings(u8 *data);
> -u64 *page_pool_ethtool_stats_get(u64 *data, void *stats);
> +u64 *page_pool_ethtool_stats_get(u64 *data, const void *stats);
>
>  bool page_pool_get_stats(const struct page_pool *pool,
>                          struct page_pool_stats *stats);
> @@ -73,7 +73,7 @@ static inline u8 *page_pool_ethtool_stats_get_strings(u8 *data)
>         return data;
>  }
>
> -static inline u64 *page_pool_ethtool_stats_get(u64 *data, void *stats)
> +static inline u64 *page_pool_ethtool_stats_get(u64 *data, const void *stats)
>  {
>         return data;
>  }
> @@ -204,8 +204,8 @@ static inline void *page_pool_dev_alloc_va(struct page_pool *pool,
>   * Get the stored dma direction. A driver might decide to store this locally
>   * and avoid the extra cache line from page_pool to determine the direction.
>   */
> -static
> -inline enum dma_data_direction page_pool_get_dma_dir(struct page_pool *pool)
> +static inline enum dma_data_direction
> +page_pool_get_dma_dir(const struct page_pool *pool)
>  {
>         return pool->p.dma_dir;
>  }
> @@ -357,7 +357,7 @@ static inline void page_pool_free_va(struct page_pool *pool, void *va,
>   * Fetch the DMA address of the page. The page pool to which the page belongs
>   * must had been created with PP_FLAG_DMA_MAP.
>   */
> -static inline dma_addr_t page_pool_get_dma_addr(struct page *page)
> +static inline dma_addr_t page_pool_get_dma_addr(const struct page *page)
>  {
>         dma_addr_t ret = page->dma_addr;
>
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index 59aca3339222..4295aec0be40 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -121,9 +121,9 @@ int page_pool_ethtool_stats_get_count(void)
>  }
>  EXPORT_SYMBOL(page_pool_ethtool_stats_get_count);
>
> -u64 *page_pool_ethtool_stats_get(u64 *data, void *stats)
> +u64 *page_pool_ethtool_stats_get(u64 *data, const void *stats)
>  {
> -       struct page_pool_stats *pool_stats = stats;
> +       const struct page_pool_stats *pool_stats = stats;
>
>         *data++ = pool_stats->alloc_stats.fast;
>         *data++ = pool_stats->alloc_stats.slow;
> @@ -360,8 +360,8 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
>         return page;
>  }
>
> -static void page_pool_dma_sync_for_device(struct page_pool *pool,
> -                                         struct page *page,
> +static void page_pool_dma_sync_for_device(const struct page_pool *pool,
> +                                         const struct page *page,
>                                           unsigned int dma_sync_size)
>  {
>         dma_addr_t dma_addr = page_pool_get_dma_addr(page);
> --
> 2.43.0
>

Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>