[PATCH AUTOSEL 4.9 03/11] dmaengine: pch_dma.c: Avoid data race between probe and irq handler

[PATCH AUTOSEL 4.9 03/11] dmaengine: pch_dma.c: Avoid data race between probe and irq handler

[Sasha Levin]

From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

[ Upstream commit 2e45676a4d33af47259fa186ea039122ce263ba9 ]

pd->dma.dev is read in irq handler pd_irq().
However, it is set to pdev->dev after request_irq().
Therefore, set pd->dma.dev to pdev->dev before request_irq() to
avoid data race between pch_dma_probe() and pd_irq().

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Link: https://lore.kernel.org/r/20200416062335.29223-1-madhuparnabhowmik10@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/dma/pch_dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/pch_dma.c b/drivers/dma/pch_dma.c
index df95727dc2fba..8a0c70e4f7277 100644
--- a/drivers/dma/pch_dma.c
+++ b/drivers/dma/pch_dma.c
@@ -876,6 +876,7 @@ static int pch_dma_probe(struct pci_dev *pdev,
 	}
 
 	pci_set_master(pdev);
+	pd->dma.dev = &pdev->dev;
 
 	err = request_irq(pdev->irq, pd_irq, IRQF_SHARED, DRV_NAME, pd);
 	if (err) {
@@ -891,7 +892,6 @@ static int pch_dma_probe(struct pci_dev *pdev,
 		goto err_free_irq;
 	}
 
-	pd->dma.dev = &pdev->dev;
 
 	INIT_LIST_HEAD(&pd->dma.channels);
 
-- 
2.20.1

[PATCH AUTOSEL 4.9 04/11] dmaengine: mmp_tdma: Reset channel error on release

[Sasha Levin]

From: Lubomir Rintel <lkundrak@v3.sk>

[ Upstream commit 0c89446379218698189a47871336cb30286a7197 ]

When a channel configuration fails, the status of the channel is set to
DEV_ERROR so that an attempt to submit it fails. However, this status
sticks until the heat end of the universe, making it impossible to
recover from the error.

Let's reset it when the channel is released so that further use of the
channel with correct configuration is not impacted.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20200419164912.670973-5-lkundrak@v3.sk
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/dma/mmp_tdma.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/dma/mmp_tdma.c b/drivers/dma/mmp_tdma.c
index 13c68b6434ce2..15b4a44e60069 100644
--- a/drivers/dma/mmp_tdma.c
+++ b/drivers/dma/mmp_tdma.c
@@ -362,6 +362,8 @@ static void mmp_tdma_free_descriptor(struct mmp_tdma_chan *tdmac)
 		gen_pool_free(gpool, (unsigned long)tdmac->desc_arr,
 				size);
 	tdmac->desc_arr = NULL;
+	if (tdmac->status == DMA_ERROR)
+		tdmac->status = DMA_COMPLETE;
 
 	return;
 }
-- 
2.20.1

[PATCH AUTOSEL 4.9 07/11] dmaengine: dmatest: Fix iteration non-stop logic

[Sasha Levin]

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

[ Upstream commit b9f960201249f20deea586b4ec814669b4c6b1c0 ]

Under some circumstances, i.e. when test is still running and about to
time out and user runs, for example,

	grep -H . /sys/module/dmatest/parameters/*

the iterations parameter is not respected and test is going on and on until
user gives

	echo 0 > /sys/module/dmatest/parameters/run

This is not what expected.

The history of this bug is interesting. I though that the commit
  2d88ce76eb98 ("dmatest: add a 'wait' parameter")
is a culprit, but looking closer to the code I think it simple revealed the
broken logic from the day one, i.e. in the commit
  0a2ff57d6fba ("dmaengine: dmatest: add a maximum number of test iterations")
which adds iterations parameter.

So, to the point, the conditional of checking the thread to be stopped being
first part of conjunction logic prevents to check iterations. Thus, we have to
always check both conditions to be able to stop after given iterations.

Since it wasn't visible before second commit appeared, I add a respective
Fixes tag.

Fixes: 2d88ce76eb98 ("dmatest: add a 'wait' parameter")
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20200424161147.16895-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/dma/dmatest.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index 7dd46cf5ed845..7a028b57a7efb 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -505,8 +505,8 @@ static int dmatest_func(void *data)
 	flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
 
 	ktime = ktime_get();
-	while (!kthread_should_stop()
-	       && !(params->iterations && total_tests >= params->iterations)) {
+	while (!(kthread_should_stop() ||
+	       (params->iterations && total_tests >= params->iterations))) {
 		struct dma_async_tx_descriptor *tx = NULL;
 		struct dmaengine_unmap_data *um;
 		dma_addr_t srcs[src_cnt];
-- 
2.20.1