diff options
| author | Geert Uytterhoeven <geert+renesas@glider.be> | 2019-06-24 14:38:18 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-08-06 19:05:21 +0200 |
| commit | 641b87ab129ac97577b3d25c19c8e677f6183907 (patch) | |
| tree | 45b24e1d844cd71ed8e0916e08ba9b573d196c59 | |
| parent | 6debf98d7702158532705bc698b1d8fb6b9612a6 (diff) | |
dmaengine: rcar-dmac: Reject zero-length slave DMA requests
[ Upstream commit 78efb76ab4dfb8f74f290ae743f34162cd627f19 ]
While the .device_prep_slave_sg() callback rejects empty scatterlists,
it still accepts single-entry scatterlists with a zero-length segment.
These may happen if a driver calls dmaengine_prep_slave_single() with a
zero len parameter. The corresponding DMA request will never complete,
leading to messages like:
rcar-dmac e7300000.dma-controller: Channel Address Error happen
and DMA timeouts.
Although requesting a zero-length DMA request is a driver bug, rejecting
it early eases debugging. Note that the .device_prep_dma_memcpy()
callback already rejects requests to copy zero bytes.
Reported-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Analyzed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/dma/sh/rcar-dmac.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c index 77b126525dac..19c7433e8309 100644 --- a/drivers/dma/sh/rcar-dmac.c +++ b/drivers/dma/sh/rcar-dmac.c @@ -1129,7 +1129,7 @@ rcar_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, struct rcar_dmac_chan *rchan = to_rcar_dmac_chan(chan); /* Someone calling slave DMA on a generic channel? */ - if (rchan->mid_rid < 0 || !sg_len) { + if (rchan->mid_rid < 0 || !sg_len || !sg_dma_len(sgl)) { dev_warn(chan->device->dev, "%s: bad parameter: len=%d, id=%d\n", __func__, sg_len, rchan->mid_rid); |