[PATCH 01/10] IB/core: Guarantee that a local_dma_lkey is available

Jason Gunthorpe
2015-07-22T23:34:34Z

Every single ULP requires a local_dma_lkey to do anything with
a QP, so let us ensure one exists for every PD created.

If the driver can supply a global local_dma_lkey then use that, otherwise
ask the driver to create a local use all physical memory MR associated
with the new PD.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Sagi Grimberg <sagig@dev.mellanox.co.il>
Acked-by: Christoph Hellwig <hch@infradead.org>
---
drivers/infiniband/core/verbs.c | 40 +++++++++++++++++++++++++++++++++++-----
include/rdma/ib_verbs.h | 2 ++
2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
index bac3fb406a74..1ddf06314f36 100644
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -213,24 +213,54 @@ EXPORT_SYMBOL(rdma_port_get_link_layer);

/* Protection domains */

+/* Return a pd for in-kernel use that has a local_dma_lkey which provides
+ local access to all physical memory. */
struct ib_pd *ib_alloc_pd(struct ib_device *device)
{
struct ib_pd *pd;
+ struct ib_device_attr devattr;
+ int rc;
+
+ rc = ib_query_device(device, &devattr);
+ if (rc)
+ return ERR_PTR(rc);

pd = device->alloc_pd(device, NULL, NULL);
+ if (IS_ERR(pd))
+ return pd;
+
+ pd->device = device;
+ pd->uobject = NULL;
+ pd->local_mr = NULL;
+ atomic_set(&pd->usecnt, 0);
+
+ if (devattr.device_cap_flags & IB_DEVICE_LOCAL_DMA_LKEY)
+ pd->local_dma_lkey = device->local_dma_lkey;
+ else {
+ struct ib_mr *mr;
+
+ mr = ib_get_dma_mr(pd, IB_ACCESS_LOCAL_WRITE);
+ if (IS_ERR(mr)) {
+ ib_dealloc_pd(pd);
+ return (struct ib_pd *)mr;
+ }

- if (!IS_ERR(pd)) {
- pd->device = device;
- pd->uobject = NULL;
- atomic_set(&pd->usecnt, 0);
+ pd->local_mr = mr;
+ pd->local_dma_lkey = pd->local_mr->lkey;
}
-
return pd;
}
+
EXPORT_SYMBOL(ib_alloc_pd);

int ib_dealloc_pd(struct ib_pd *pd)
{
+ if (pd->local_mr) {
+ if (ib_dereg_mr(pd->local_mr))
+ return -EBUSY;
+ pd->local_mr = NULL;
+ }
+
if (atomic_read(&pd->usecnt))
return -EBUSY;

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 986fddb08579..cfda95d7b067 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1255,6 +1255,8 @@ struct ib_pd {
struct ib_device *device;
struct ib_uobject *uobject;
atomic_t usecnt; /* count all resources */
+ struct ib_mr *local_mr;
+ u32 local_dma_lkey;
};

struct ib_xrcd {
--
2.1.4