Commit 66983bc1 authored by Nikhil Rao's avatar Nikhil Rao Committed by Vinod Koul
Browse files

dmaengine: idxd: fix cdev locking for open and release 



add the wq lock in cdev open and release call. This fixes
race conditions observed in the open and close routines.

Fixes: 42d279f9 ("dmaengine: idxd: add char driver to expose submission portal to userland")
Signed-off-by: default avatarNikhil Rao <nikhil.rao@intel.com>
Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/159285824892.64944.2905413694915141834.stgit@djiang5-desk3.ch.intel.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 2f57b8d5

drivers/dma/idxd/cdev.c

+16 −3
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp) 
	struct idxd_device *idxd;

	struct idxd_wq *wq;

	struct device *dev;

	int rc = 0;



	wq = inode_wq(inode);

	idxd = wq->idxd;
@@ -81,17 +82,27 @@ static int idxd_cdev_open(struct inode *inode, struct file *filp) 


	dev_dbg(dev, "%s called: %d\n", __func__, idxd_wq_refcount(wq));



	if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq))

		return -EBUSY;



	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);

	if (!ctx)

		return -ENOMEM;



	mutex_lock(&wq->wq_lock);



	if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq)) {

		rc = -EBUSY;

		goto failed;

	}



	ctx->wq = wq;

	filp->private_data = ctx;

	idxd_wq_get(wq);

	mutex_unlock(&wq->wq_lock);

	return 0;



 failed:

	mutex_unlock(&wq->wq_lock);

	kfree(ctx);

	return rc;

}



static int idxd_cdev_release(struct inode *node, struct file *filep)
@@ -105,7 +116,9 @@ static int idxd_cdev_release(struct inode *node, struct file *filep) 
	filep->private_data = NULL;



	kfree(ctx);

	mutex_lock(&wq->wq_lock);

	idxd_wq_put(wq);

	mutex_unlock(&wq->wq_lock);

	return 0;

}