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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 5.10 06/20] dmaengine: of-dma: router_xlate to return -EPROBE_DEFER if controller is not yet available
Date: Tue, 10 Aug 2021 10:15:24 -0400	[thread overview]
Message-ID: <20210810141538.3117707-6-sashal@kernel.org> (raw)
In-Reply-To: <20210810141538.3117707-1-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 8a4f608904b9..4be433482053 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)) {
@@ -79,6 +83,7 @@ static struct dma_chan *of_dma_router_xlate(struct of_phandle_args *dma_spec,
 		chan->route_data = route_data;
 	}
 
+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


  parent reply	other threads:[~2021-08-10 14:17 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-10 14:15 [PATCH AUTOSEL 5.10 01/20] dmaengine: xilinx_dma: Fix read-after-free bug when terminating transfers Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 02/20] dmaengine: usb-dmac: Fix PM reference leak in usb_dmac_probe() Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 03/20] spi: spi-mux: Add module info needed for autoloading Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 04/20] net: xfrm: Fix end of loop tests for list_for_each_entry Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 05/20] ARM: dts: am43x-epos-evm: Reduce i2c0 bus speed for tps65218 Sasha Levin
2021-08-10 14:15 ` Sasha Levin [this message]
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 07/20] scsi: pm80xx: Fix TMF task completion race condition Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 08/20] scsi: megaraid_mm: Fix end of loop tests for list_for_each_entry() Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 09/20] scsi: scsi_dh_rdac: Avoid crash during rdac_bus_attach() Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 10/20] scsi: core: Avoid printing an error if target_alloc() returns -ENXIO Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 11/20] scsi: core: Fix capacity set to zero after offlinining device Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 12/20] drm/amdgpu: fix the doorbell missing when in CGPG issue for renoir Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 13/20] qede: fix crash in rmmod qede while automatic debug collection Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 14/20] ARM: dts: nomadik: Fix up interrupt controller node names Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 16/20] Revert "ACPICA: Fix memory leak caused by _CID repair function" Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 17/20] net: usb: pegasus: Check the return value of get_geristers() and friends; Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 18/20] net: usb: lan78xx: don't modify phy_device state concurrently Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 19/20] drm/amd/display: Fix Dynamic bpp issue with 8K30 with Navi 1X Sasha Levin
2021-08-10 14:15 ` [PATCH AUTOSEL 5.10 20/20] drm/amd/display: workaround for hard hang on HPD on native DP Sasha Levin

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