From: Koba Ko <koba.ko@canonical.com>
To: Vinod Koul <vkoul@kernel.org>,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
Jerry Snitselaar <jsnitsel@redhat.com>,
Jie Hai <haijie1@huawei.com>, Dave Jiang <dave.jiang@intel.com>
Subject: [PATCH V2] dmaengine: Fix client_count is countered one more incorrectly.
Date: Sat, 1 Oct 2022 01:36:52 +0800 [thread overview]
Message-ID: <20220930173652.1251349-1-koba.ko@canonical.com> (raw)
If the passed client_count is 0,
it would be incremented by balance_ref_count first
then increment one more.
This would cause client_count to 2.
cat /sys/class/dma/dma0chan*/in_use
2
2
2
Fixes: d2f4f99db3e9 ("dmaengine: Rework dma_chan_get")
Signed-off-by: Koba Ko <koba.ko@canonical.com>
Reviewed-by: Jie Hai <haijie1@huawei.com>
Test-by: Jie Hai <haijie1@huawei.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
---
V2: Remove [3/3] on subject.
---
drivers/dma/dmaengine.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 2cfa8458b51be..78f8a9f3ad825 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -451,7 +451,8 @@ static int dma_chan_get(struct dma_chan *chan)
/* The channel is already in use, update client count */
if (chan->client_count) {
__module_get(owner);
- goto out;
+ chan->client_count++;
+ return 0;
}
if (!try_module_get(owner))
@@ -470,11 +471,11 @@ static int dma_chan_get(struct dma_chan *chan)
goto err_out;
}
+ chan->client_count++;
+
if (!dma_has_cap(DMA_PRIVATE, chan->device->cap_mask))
balance_ref_count(chan);
-out:
- chan->client_count++;
return 0;
err_out:
--
2.25.1
next reply other threads:[~2022-09-30 17:37 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-30 17:36 Koba Ko [this message]
2022-09-30 18:39 ` [PATCH V2] dmaengine: Fix client_count is countered one more incorrectly Joel Savitz
2022-11-02 18:07 ` Jerry Snitselaar
2022-11-04 13:25 ` Vinod Koul
2022-11-04 15:36 ` Jerry Snitselaar
2022-11-05 7:18 ` Vinod Koul
2022-11-16 6:32 ` Koba Ko
2022-11-22 2:06 ` Koba Ko
-- strict thread matches above, loose matches on Subject: below --
2022-11-22 17:46 Joel Savitz
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