[Patch v2 3/4] uio_hv_generic: Adjust ring size according to system page alignment

[longli@linuxonhyperv.com]

From: Long Li <longli@microsoft.com>

Following the ring header, the ring data should align to system page
boundary. Adjust the size if necessary.

Cc: stable@vger.kernel.org
Fixes: 95096f2fbd10 ("uio-hv-generic: new userspace i/o driver for VMBus")
Signed-off-by: Long Li <longli@microsoft.com>
---
 drivers/uio/uio_hv_generic.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
index 08385b04c4ab..dfc5f0e1a254 100644
--- a/drivers/uio/uio_hv_generic.c
+++ b/drivers/uio/uio_hv_generic.c
@@ -256,6 +256,12 @@ hv_uio_probe(struct hv_device *dev,
 	if (!ring_size)
 		ring_size = SZ_2M;
 
+	/*
+	 * Adjust ring size if necessary to have the ring data region page
+	 * aligned
+	 */
+	ring_size = VMBUS_RING_SIZE(ring_size);
+
 	pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
 		return -ENOMEM;
-- 
2.34.1