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From: Dmitry Osipenko <digetx@gmail.com>
To: "Laxman Dewangan" <ldewangan@nvidia.com>,
	"Vinod Koul" <vkoul@kernel.org>,
	"Dan Williams" <dan.j.williams@intel.com>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Jonathan Hunter" <jonathanh@nvidia.com>,
	"Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: dmaengine@vger.kernel.org, linux-tegra@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v5 03/14] dmaengine: tegra-apb: Prevent race conditions on channel's freeing
Date: Fri, 24 Jan 2020 02:03:14 +0300	[thread overview]
Message-ID: <20200123230325.3037-4-digetx@gmail.com> (raw)
In-Reply-To: <20200123230325.3037-1-digetx@gmail.com>

It's incorrect to check the channel's "busy" state without taking a lock.
That shouldn't cause any real troubles, nevertheless it's always better
not to have any race conditions in the code.

Acked-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/dma/tegra20-apb-dma.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 664e9c5df3ba..24ad3a5a04e3 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -1294,8 +1294,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
 
 	dev_dbg(tdc2dev(tdc), "Freeing channel %d\n", tdc->id);
 
-	if (tdc->busy)
-		tegra_dma_terminate_all(dc);
+	tegra_dma_terminate_all(dc);
 
 	spin_lock_irqsave(&tdc->lock, flags);
 	list_splice_init(&tdc->pending_sg_req, &sg_req_list);
-- 
2.24.0


WARNING: multiple messages have this Message-ID (diff)
From: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: "Laxman Dewangan"
	<ldewangan-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
	"Vinod Koul" <vkoul-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	"Dan Williams"
	<dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	"Thierry Reding"
	<thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"Jonathan Hunter"
	<jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
	"Michał Mirosław"
	<mirq-linux-CoA6ZxLDdyEEUmgCuDUIdw@public.gmane.org>
Cc: dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [PATCH v5 03/14] dmaengine: tegra-apb: Prevent race conditions on channel's freeing
Date: Fri, 24 Jan 2020 02:03:14 +0300	[thread overview]
Message-ID: <20200123230325.3037-4-digetx@gmail.com> (raw)
In-Reply-To: <20200123230325.3037-1-digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

It's incorrect to check the channel's "busy" state without taking a lock.
That shouldn't cause any real troubles, nevertheless it's always better
not to have any race conditions in the code.

Acked-by: Jon Hunter <jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Signed-off-by: Dmitry Osipenko <digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/dma/tegra20-apb-dma.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 664e9c5df3ba..24ad3a5a04e3 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -1294,8 +1294,7 @@ static void tegra_dma_free_chan_resources(struct dma_chan *dc)
 
 	dev_dbg(tdc2dev(tdc), "Freeing channel %d\n", tdc->id);
 
-	if (tdc->busy)
-		tegra_dma_terminate_all(dc);
+	tegra_dma_terminate_all(dc);
 
 	spin_lock_irqsave(&tdc->lock, flags);
 	list_splice_init(&tdc->pending_sg_req, &sg_req_list);
-- 
2.24.0

  parent reply	other threads:[~2020-01-23 23:11 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-23 23:03 [PATCH v5 00/14] NVIDIA Tegra APB DMA driver fixes and improvements Dmitry Osipenko
2020-01-23 23:03 ` Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 01/14] dmaengine: tegra-apb: Fix use-after-free Dmitry Osipenko
2020-01-29 10:56   ` Jon Hunter
2020-01-29 10:56     ` Jon Hunter
2020-01-29 14:38     ` Dmitry Osipenko
2020-01-29 14:38       ` Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 02/14] dmaengine: tegra-apb: Implement synchronization hook Dmitry Osipenko
2020-01-23 23:03   ` Dmitry Osipenko
2020-01-23 23:03 ` Dmitry Osipenko [this message]
2020-01-23 23:03   ` [PATCH v5 03/14] dmaengine: tegra-apb: Prevent race conditions on channel's freeing Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 04/14] dmaengine: tegra-apb: Clean up tasklet releasing Dmitry Osipenko
2020-01-23 23:03   ` Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 05/14] dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list Dmitry Osipenko
2020-01-29 11:01   ` Jon Hunter
2020-01-29 11:01     ` Jon Hunter
2020-01-29 14:39     ` Dmitry Osipenko
2020-01-29 14:39       ` Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 06/14] dmaengine: tegra-apb: Use devm_platform_ioremap_resource Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 07/14] dmaengine: tegra-apb: Use devm_request_irq Dmitry Osipenko
2020-01-23 23:03   ` Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 08/14] dmaengine: tegra-apb: Fix coding style problems Dmitry Osipenko
2020-01-29 11:03   ` Jon Hunter
2020-01-29 11:03     ` Jon Hunter
2020-01-29 14:31     ` Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 09/14] dmaengine: tegra-apb: Remove assumptions about unavailable runtime PM Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 10/14] dmaengine: tegra-apb: Keep clock enabled only during of DMA transfer Dmitry Osipenko
2020-01-23 23:03   ` Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 11/14] dmaengine: tegra-apb: Clean up suspend-resume Dmitry Osipenko
2020-01-23 23:03   ` Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 12/14] dmaengine: tegra-apb: Add missing of_dma_controller_free Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 13/14] dmaengine: tegra-apb: Allow to compile as a loadable kernel module Dmitry Osipenko
2020-01-23 23:03   ` Dmitry Osipenko
2020-01-23 23:03 ` [PATCH v5 14/14] dmaengine: tegra-apb: Remove MODULE_ALIAS Dmitry Osipenko
2020-01-23 23:03   ` Dmitry Osipenko

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