From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Peter Ujfalusi <peter.ujfalusi@gmail.com>,
Vinod Koul <vkoul@kernel.org>, Sasha Levin <sashal@kernel.org>,
dmaengine@vger.kernel.org
Subject: [PATCH AUTOSEL 5.13 06/24] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available
Date: Tue, 10 Aug 2021 10:14:47 -0400 [thread overview]
Message-ID: <20210810141505.3117318-6-sashal@kernel.org> (raw)
In-Reply-To: <20210810141505.3117318-1-sashal@kernel.org>
From: Peter Ujfalusi <peter.ujfalusi@gmail.com>
[ Upstream commit eda97cb095f2958bbad55684a6ca3e7d7af0176a ]
If the router_xlate can not find the controller in the available DMA
devices then it should return with -EPORBE_DEFER in a same way as the
of_dma_request_slave_channel() does.
The issue can be reproduced if the event router is registered before the
DMA controller itself and a driver would request for a channel before the
controller is registered.
In of_dma_request_slave_channel():
1. of_dma_find_controller() would find the dma_router
2. ofdma->of_dma_xlate() would fail and returned NULL
3. -ENODEV is returned as error code
with this patch we would return in this case the correct -EPROBE_DEFER and
the client can try to request the channel later.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Link: https://lore.kernel.org/r/20210717190021.21897-1-peter.ujfalusi@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/of-dma.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index ec00b20ae8e4..ac61ecda2926 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -67,8 +67,12 @@ static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec,
return NULL;
ofdma_target = of_dma_find_controller(&dma_spec_target);
- if (!ofdma_target)
- return NULL;
+ if (!ofdma_target) {
+ ofdma->dma_router->route_free(ofdma->dma_router->dev,
+ route_data);
+ chan = ERR_PTR(-EPROBE_DEFER);
+ goto err;
+ }
chan = ofdma_target->of_dma_xlate(&dma_spec_target, ofdma_target);
if (IS_ERR_OR_NULL(chan)) {
@@ -89,6 +93,7 @@ static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec,
}
}
+err:
/*
* Need to put the node back since the ofdma->of_dma_route_allocate
* has taken it for generating the new, translated dma_spec
--
2.30.2
prev parent reply other threads:[~2021-08-10 14:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-10 14:14 [PATCH AUTOSEL 5.13 01/24] dmaengine: xilinx_dma: Fix read-after-free bug when terminating transfers Sasha Levin
2021-08-10 14:14 ` [PATCH AUTOSEL 5.13 02/24] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe() Sasha Levin
2021-08-10 14:14 ` Sasha Levin [this message]
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