IB/hfi1: Fix user context tail allocation for DMA_RTAIL

The following code fails to allocate a buffer for the
tail address that the hardware DMAs into when the user
context DMA_RTAIL is set.

if (HFI1_CAP_KGET_MASK(rcd->flags, DMA_RTAIL)) {
	rcd->rcvhdrtail_kvaddr = dma_zalloc_coherent(
		&dd->pcidev->dev, PAGE_SIZE, &dma_hdrqtail,
                gfp_flags);
	if (!rcd->rcvhdrtail_kvaddr)
		goto bail_free;
	rcd->rcvhdrqtailaddr_dma = dma_hdrqtail;
}

So the rcvhdrtail_kvaddr would then be NULL.

The mmap logic fails to check for a NULL rcvhdrtail_kvaddr.

The fix is to test for both user and kernel DMA_TAIL options
during the allocation as well as testing for a NULL
rcvhdrtail_kvaddr during the mmap processing.

Additionally, all downstream testing of the capmask for DMA_RTAIL
have been eliminated in favor of testing rcvhdrtail_kvaddr.

Cc: <stable@vger.kernel.org> # 4.9.x
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c
index c9d23c37a371..0fc4aa9455c3 100644
--- a/drivers/infiniband/hw/hfi1/file_ops.c
+++ b/drivers/infiniband/hw/hfi1/file_ops.c
@@ -505,7 +505,7 @@ static int hfi1_file_mmap(struct file *fp, struct vm_area_struct *vma)
 			ret = -EINVAL;
 			goto done;
 		}
-		if (flags & VM_WRITE) {
+		if ((flags & VM_WRITE) || !uctxt->rcvhdrtail_kvaddr) {
 			ret = -EPERM;
 			goto done;
 		}