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From: Dave Jiang <dave.jiang@intel.com>
To: vkoul@kernel.org
Cc: dmaengine@vger.kernel.org
Subject: [PATCH v2] dmaengine: idxd: fix off by one on cdev dwq refcount
Date: Thu, 12 Mar 2020 09:23:53 -0700	[thread overview]
Message-ID: <158403020187.10208.14117394394540710774.stgit@djiang5-desk3.ch.intel.com> (raw)

The refcount check for dedicated workqueue (dwq) is off by one and allows
more than 1 user to open the char device. Fix check so only a single user
can open the device.

Fixes: 42d279f9137a ("dmaengine: idxd: add char driver to expose submission portal to userland")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---

v2: Vinod: Fix spelling error in commit message.

 drivers/dma/idxd/cdev.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index d58144eca6e8..ff49847e37a8 100644
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -79,9 +79,9 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp)
 	idxd = wq->idxd;
 	dev = &idxd->pdev->dev;
 
-	dev_dbg(dev, "%s called\n", __func__);
+	dev_dbg(dev, "%s called: %d\n", __func__, idxd_wq_refcount(wq));
 
-	if (idxd_wq_refcount(wq) > 1 && wq_dedicated(wq))
+	if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq))
 		return -EBUSY;
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);


             reply	other threads:[~2020-03-12 16:24 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-12 16:23 Dave Jiang [this message]
2020-03-23  6:02 ` [PATCH v2] dmaengine: idxd: fix off by one on cdev dwq refcount Vinod Koul

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