From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Vinod Koul <vkoul@kernel.org>
Cc: dmaengine@vger.kernel.org, Hyun Kwon <hyun.kwon@xilinx.com>,
Michal Simek <michal.simek@xilinx.com>
Subject: Re: [PATCH 1/3] dmaengine: xilinx: dpdma: remove comparison of unsigned expression
Date: Wed, 22 Jul 2020 15:44:58 +0300 [thread overview]
Message-ID: <20200722124458.GF5833@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20200718135201.191881-1-vkoul@kernel.org>
Hi Vinod,
Thank you for the patch.
On Sat, Jul 18, 2020 at 07:21:59PM +0530, Vinod Koul wrote:
> xilinx_dpdma_config() channel id is unsigned int and compares with
> ZYNQMP_DPDMA_VIDEO0 which is zero, so remove this comparison
>
> drivers/dma/xilinx/xilinx_dpdma.c:1073:15: warning: comparison of
> unsigned expression in ‘>= 0’ is always true [-Wtype-limits] if
> (chan->id >= ZYNQMP_DPDMA_VIDEO0 && chan->id <= ZYNQMP_DPDMA_VIDEO2)
I didn't see that warning, how do you produce it ?
> Signed-off-by: Vinod Koul <vkoul@kernel.org>
> ---
> drivers/dma/xilinx/xilinx_dpdma.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/xilinx/xilinx_dpdma.c b/drivers/dma/xilinx/xilinx_dpdma.c
> index af88a6762ef4..8e602378f2dc 100644
> --- a/drivers/dma/xilinx/xilinx_dpdma.c
> +++ b/drivers/dma/xilinx/xilinx_dpdma.c
> @@ -1070,7 +1070,7 @@ static int xilinx_dpdma_config(struct dma_chan *dchan,
> * Abuse the slave_id to indicate that the channel is part of a video
> * group.
> */
> - if (chan->id >= ZYNQMP_DPDMA_VIDEO0 && chan->id <= ZYNQMP_DPDMA_VIDEO2)
> + if (chan->id <= ZYNQMP_DPDMA_VIDEO2)
While this doesn't affect the behaviour, I'm worried about the risk of
introducing bugs in the future if the ZYNQMP_DPDMA_VIDEO0 becomes
non-zero. On the other hand, that's part of the DT ABI, so it shouldn't
change. How about
switch (chan->id) {
case ZYNQMP_DPDMA_VIDEO0:
case ZYNQMP_DPDMA_VIDEO1:
case ZYNQMP_DPDMA_VIDEO2:
chan->video_group = config->slave_id != 0;
break;
}
instead ?
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> chan->video_group = config->slave_id != 0;
>
> spin_unlock_irqrestore(&chan->lock, flags);
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2020-07-22 12:45 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-18 13:51 [PATCH 1/3] dmaengine: xilinx: dpdma: remove comparison of unsigned expression Vinod Koul
2020-07-18 13:52 ` [PATCH 2/3] dmaengine: xilinx: dpdma: add missing kernel doc Vinod Koul
2020-07-22 12:45 ` Laurent Pinchart
2020-07-18 13:52 ` [PATCH 3/3] dmaengine: xilinx: dpdma: fix kernel doc format Vinod Koul
2020-07-22 13:11 ` Laurent Pinchart
2020-07-22 14:26 ` Vinod Koul
2020-07-22 14:51 ` Laurent Pinchart
2020-07-22 14:54 ` Vinod Koul
2020-07-22 16:18 ` Laurent Pinchart
2020-07-22 12:44 ` Laurent Pinchart [this message]
2020-07-22 14:25 ` [PATCH 1/3] dmaengine: xilinx: dpdma: remove comparison of unsigned expression Vinod Koul
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