From 988aad2f111c768c66efc87d073c73ecb32b682c Mon Sep 17 00:00:00 2001 From: Dave Jiang Date: Thu, 12 Mar 2020 09:23:53 -0700 Subject: dmaengine: idxd: fix off by one on cdev dwq refcount 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 Link: https://lore.kernel.org/r/158403020187.10208.14117394394540710774.stgit@djiang5-desk3.ch.intel.com Signed-off-by: Vinod Koul --- 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 df47be612ebb..989b7a25ca61 100644 --- a/drivers/dma/idxd/cdev.c +++ b/drivers/dma/idxd/cdev.c @@ -81,9 +81,9 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp) dev = &idxd->pdev->dev; idxd_cdev = &wq->idxd_cdev; - 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); -- cgit