The commit referenced below performs additional checking on
devices used for DMA. Specifically it checks that
device->dma_mask != NULL
Rdma_rxe uses this device when pinning MR memory but did not
set the value of dma_mask. In fact rdma_rxe does not perform
any DMA operations so the value is never used but is checked.
This patch gives dma_mask a valid value extracted from the device
backing the ndev used by rxe.
Without this patch rdma_rxe does not function.
N.B. This patch needs to be applied before the recent fix to add back
IB_USER_VERBS_CMD_POST_SEND to uverbs_cmd_mask.
Dennis Dallesandro reported that Parav's similar patch did not apply
cleanly to rxe. This one does to for-next head of tree as of yesterday.
Fixes: f959dcd6ddfd2 ("dma-direct: Fix potential NULL pointer dereference")
Signed-off-by: Bob Pearson <rpearson@xxxxxxx>
---
drivers/infiniband/sw/rxe/rxe_verbs.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 7652d53af2c1..c857e83323ed 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -1128,19 +1128,32 @@ int rxe_register_device(struct rxe_dev *rxe, const char *ibdev_name)
int err;
struct ib_device *dev = &rxe->ib_dev;
struct crypto_shash *tfm;
+ u64 dma_mask;
strlcpy(dev->node_desc, "rxe", sizeof(dev->node_desc));
dev->node_type = RDMA_NODE_IB_CA;
dev->phys_port_cnt = 1;
dev->num_comp_vectors = num_possible_cpus();
- dev->dev.parent = rxe_dma_device(rxe);
dev->local_dma_lkey = 0;
addrconf_addr_eui48((unsigned char *)&dev->node_guid,
rxe->ndev->dev_addr);
dev->dev.dma_parms = &rxe->dma_parms;
dma_set_max_seg_size(&dev->dev, UINT_MAX);
- dma_set_coherent_mask(&dev->dev, dma_get_required_mask(&dev->dev));
+
+ /* rdma_rxe never does real DMA but does rely on
+ * pinning user memory in MRs to avoid page faults
+ * in responder and completer tasklets. This code
+ * supplies a valid dma_mask from the underlying
+ * network device. It is never used but is checked.
+ */
+ dev->dev.parent = rxe_dma_device(rxe);
+ dma_mask = *(dev->dev.parent->dma_mask);
+ err = dma_coerce_mask_and_coherent(&dev->dev, dma_mask);
+ if (err) {
+ pr_warn("dma_mask not supported\n");
+ return err;
+ }
dev->uverbs_cmd_mask |= BIT_ULL(IB_USER_VERBS_CMD_REQ_NOTIFY_CQ);
--
2.27.0
