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dmaengine: idxd: fix cdev locking for open and release

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

Fixes: 42d279f913 ("dmaengine: idxd: add char driver to expose submission portal to userland")
Signed-off-by: Nikhil Rao <nikhil.rao@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/159285824892.64944.2905413694915141834.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Nikhil Rao 2020-06-22 13:38:34 -07:00 committed by Vinod Koul
parent 2f57b8d576
commit 66983bc18f
1 changed files with 16 additions and 3 deletions
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19
drivers/dma/idxd/cdev.c
View file

@ -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;
}