Re: [PATCH V2] tty: serial: fsl_lpuart: use the sg count from dma_map_sg

[gregkh@xxxxxxxxxxxxxxxxxxx]

On Thu, Nov 07, 2019 at 02:50:11AM +0000, Peng Fan wrote:
> From: Peng Fan <peng.fan@xxxxxxx>
> 
> The dmaengine_prep_slave_sg needs to use sg count returned
> by dma_map_sg, not use sport->dma_tx_nents, because the return
> value of dma_map_sg is not always same with "nents".
> 
> When enabling iommu for lpuart + edma, iommu framework may concatenate
> two sgs into one.
> 
> Fixes: 6250cc30c4c4e ("tty: serial: fsl_lpuart: Use scatter/gather DMA for Tx")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
> ---
> 
> V2:
>  Assign ret to sport->dma_tx_nents, then we no need to fix dma_unmap_sg
>  Hi Greg,
>   I saw v1 patch merged to tty-next, please help to replace with V2 if this
>   is ok for you, or you need I have a follow up fix for v1.

I can not "replace" anything, my tree does not rebase, sorry.  Please
send fix-up patches on top of it if there is any changes that need to
happen.

thanks,

greg k-h