On Mon, Jan 08, 2018 at 10:50:50AM -0500, Zi Yan wrote:
> From: Zi Yan <zi.yan@xxxxxxxxxxxxxx>
>
> When CONFIG_DMA_ENGINE_RAID is enabled, unmap pool size can reach to
> 256. But in struct dmaengine_unmap_data, map_cnt is only u8, wrapping
> to 0, if the unmap pool is maximally used. This triggers BUG() when
> struct dmaengine_unmap_data is freed. Use u16 to fix the problem.
>
> Signed-off-by: Zi Yan <zi.yan@xxxxxxxxxxxxxx>
> ---
> include/linux/dmaengine.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index f838764993eb..861be5cab1df 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -470,7 +470,11 @@ typedef void (*dma_async_tx_callback_result)(void *dma_async_param,
> const struct dmaengine_result *result);
>
> struct dmaengine_unmap_data {
> +#if IS_ENABLED(CONFIG_DMA_ENGINE_RAID)
> + u16 map_cnt;
> +#else
> u8 map_cnt;
> +#endif
> u8 to_cnt;
> u8 from_cnt;
> u8 bidi_cnt;
Would that cause adverse performance, the data structure is not aligned
anymore. Dan was that a consideration while adding this?
--
~Vinod
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