linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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 05/14] dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list
Date: Fri, 24 Jan 2020 02:03:16 +0300	[thread overview]
Message-ID: <20200123230325.3037-6-digetx@gmail.com> (raw)
In-Reply-To: <20200123230325.3037-1-digetx@gmail.com>

The interrupt handler puts a half-completed DMA descriptor on a free list
and then schedules tasklet to process bottom half of the descriptor that
executes client's callback, this creates possibility to pick up the busy
descriptor from the free list. Thus let's disallow descriptor's re-use
until it is fully processed.

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

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 1b8a11804962..aafad50d075e 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -281,7 +281,7 @@ static struct tegra_dma_desc *tegra_dma_desc_get(
 
 	/* Do not allocate if desc are waiting for ack */
 	list_for_each_entry(dma_desc, &tdc->free_dma_desc, node) {
-		if (async_tx_test_ack(&dma_desc->txd)) {
+		if (async_tx_test_ack(&dma_desc->txd) && !dma_desc->cb_count) {
 			list_del(&dma_desc->node);
 			spin_unlock_irqrestore(&tdc->lock, flags);
 			dma_desc->txd.flags = 0;
-- 
2.24.0


  parent reply	other threads:[~2020-01-23 23:10 UTC|newest]

Thread overview: 21+ 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 ` [PATCH v5 01/14] dmaengine: tegra-apb: Fix use-after-free Dmitry Osipenko
2020-01-29 10:56   ` Jon Hunter
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 ` [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 [this message]
2020-01-29 11:01   ` [PATCH v5 05/14] dmaengine: tegra-apb: Prevent race conditions of tasklet vs free list Jon Hunter
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 ` [PATCH v5 08/14] dmaengine: tegra-apb: Fix coding style problems Dmitry Osipenko
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 ` [PATCH v5 11/14] dmaengine: tegra-apb: Clean up suspend-resume 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 ` [PATCH v5 14/14] dmaengine: tegra-apb: Remove MODULE_ALIAS Dmitry Osipenko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200123230325.3037-6-digetx@gmail.com \
    --to=digetx@gmail.com \
    --cc=dan.j.williams@intel.com \
    --cc=dmaengine@vger.kernel.org \
    --cc=jonathanh@nvidia.com \
    --cc=ldewangan@nvidia.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-tegra@vger.kernel.org \
    --cc=mirq-linux@rere.qmqm.pl \
    --cc=thierry.reding@gmail.com \
    --cc=vkoul@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).