[PATCH rdma-next v2 13/15] RDMA/uverbs: Add new Unordered MR access flag

[Michael Gur]

Add a new Unordered access flag for MR registrations.
This access flag allows additional relaxing of the order of memory
accesses to the memory region.
Using this access flag allows for concurrent reads and writes of this MR
to be reordered.

This access flag is part of the optional access flags range, drivers
shouldn't fail registration for any value in this range and are expected
to treat them as best-effort.

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Reviewed-by: Yishai Hadas <yishaih@xxxxxxxxxx>
Signed-off-by: Michael Gur <michaelgur@xxxxxxxxxx>
---
 drivers/infiniband/core/umem.c          | 2 +-
 include/rdma/ib_verbs.h                 | 1 +
 include/uapi/rdma/ib_user_ioctl_verbs.h | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index b1ab4f0359b0..e07c5d439fbe 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -211,7 +211,7 @@ static struct ib_umem *__ib_umem_get_va(struct ib_device *device,
 	umem->dma_dir    = dir;
 	umem->owning_mm = mm = current->mm;
 	umem->dma_attrs = DMA_ATTR_REQUIRE_COHERENT;
-	if (access & IB_ACCESS_RELAXED_ORDERING)
+	if (access & (IB_ACCESS_RELAXED_ORDERING | IB_ACCESS_UNORDERED))
 		umem->dma_attrs |= DMA_ATTR_WEAK_ORDERING;
 
 	mmgrab(mm);
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index d6eaa3fee66e..29228226a236 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1505,6 +1505,7 @@ enum ib_access_flags {
 	IB_ACCESS_ON_DEMAND = IB_UVERBS_ACCESS_ON_DEMAND,
 	IB_ACCESS_HUGETLB = IB_UVERBS_ACCESS_HUGETLB,
 	IB_ACCESS_RELAXED_ORDERING = IB_UVERBS_ACCESS_RELAXED_ORDERING,
+	IB_ACCESS_UNORDERED = IB_UVERBS_ACCESS_UNORDERED,
 	IB_ACCESS_FLUSH_GLOBAL = IB_UVERBS_ACCESS_FLUSH_GLOBAL,
 	IB_ACCESS_FLUSH_PERSISTENT = IB_UVERBS_ACCESS_FLUSH_PERSISTENT,
 
diff --git a/include/uapi/rdma/ib_user_ioctl_verbs.h b/include/uapi/rdma/ib_user_ioctl_verbs.h
index 21f86cc7bb1f..ca8b8b8d28f2 100644
--- a/include/uapi/rdma/ib_user_ioctl_verbs.h
+++ b/include/uapi/rdma/ib_user_ioctl_verbs.h
@@ -62,6 +62,7 @@ enum ib_uverbs_access_flags {
 	IB_UVERBS_ACCESS_FLUSH_PERSISTENT = 1 << 9,
 
 	IB_UVERBS_ACCESS_RELAXED_ORDERING = IB_UVERBS_ACCESS_OPTIONAL_FIRST,
+	IB_UVERBS_ACCESS_UNORDERED = IB_UVERBS_ACCESS_OPTIONAL_FIRST << 1,
 	IB_UVERBS_ACCESS_OPTIONAL_RANGE =
 		((IB_UVERBS_ACCESS_OPTIONAL_LAST << 1) - 1) &
 		~(IB_UVERBS_ACCESS_OPTIONAL_FIRST - 1)
-- 
2.52.0