[PATCH rdma-next] RDMA/mana_ib: advertise pow2 RC SQ support to user space

[Snehal Sanghvi <snsanghvi@linux.microsoft.com>]

From: Snehal Sanghvi <snsanghvi@microsoft.com>

The send queue of an RC QP normally needs an extra rollback area in
shared memory. With fixed-size WQEs the rollback can be derived from the
WQE size alone, so an adapter supporting it can accept a plain
power-of-two send queue and the rollback area becomes unnecessary.

Report the adapter capability to user space with a new comp_mask bit in
the alloc ucontext response, so that user space can request a
power-of-two RC send queue when the adapter supports it.

Signed-off-by: Snehal Sanghvi <snsanghvi@microsoft.com>
Reviewed-by: Konstantin Taranov <kotaranov@microsoft.com>
---
 drivers/infiniband/hw/mana/main.c    | 2 ++
 drivers/infiniband/hw/mana/mana_ib.h | 1 +
 include/uapi/rdma/mana-abi.h         | 1 +
 3 files changed, 4 insertions(+)

diff --git a/drivers/infiniband/hw/mana/main.c b/drivers/infiniband/hw/mana/main.c
index 83a97f1c5c..672bd3f650 100644
--- a/drivers/infiniband/hw/mana/main.c
+++ b/drivers/infiniband/hw/mana/main.c
@@ -248,6 +248,8 @@ int mana_ib_alloc_ucontext(struct ib_ucontext *ibcontext,
 	ucontext->doorbell = doorbell_page;
 	ucmd_resp.comp_mask = MANA_IB_UCNTX_ALLOC_PDN_SUPPORT;
 	ucmd_resp.comp_mask |= MANA_IB_UCNTX_RC_EXT_SUPPORT;
+	if (mdev->adapter_caps.feature_flags & MANA_IB_FEATURE_RC_QP_SQ_POW2_SUPPORT)
+		ucmd_resp.comp_mask |= MANA_IB_UCNTX_RC_SQ_POW2_SUPPORT;
 	ret = ib_respond_udata(udata, ucmd_resp);
 	if (ret)
 		return ret;
diff --git a/drivers/infiniband/hw/mana/mana_ib.h b/drivers/infiniband/hw/mana/mana_ib.h
index 1be33ed8bd..4da110b302 100644
--- a/drivers/infiniband/hw/mana/mana_ib.h
+++ b/drivers/infiniband/hw/mana/mana_ib.h
@@ -268,6 +268,7 @@ enum mana_ib_adapter_features {
 	MANA_IB_FEATURE_DEV_COUNTERS_SUPPORT = BIT(5),
 	MANA_IB_FEATURE_MULTI_PORTS_SUPPORT = BIT(6),
 	MANA_IB_FEATURE_MSN_IN_WQE_SUPPORT = BIT(7),
+	MANA_IB_FEATURE_RC_QP_SQ_POW2_SUPPORT = BIT(14),
 	MANA_IB_FEATURE_MULTI_PORT_GSI_SUPPORT = BIT(15),
 };
 
diff --git a/include/uapi/rdma/mana-abi.h b/include/uapi/rdma/mana-abi.h
index c9a2417666..ebc9a655b8 100644
--- a/include/uapi/rdma/mana-abi.h
+++ b/include/uapi/rdma/mana-abi.h
@@ -111,6 +111,7 @@ struct mana_ib_create_qp_rss_resp {
 enum mana_ib_ucontext_support {
 	MANA_IB_UCNTX_ALLOC_PDN_SUPPORT = 1 << 0,
 	MANA_IB_UCNTX_RC_EXT_SUPPORT = 1 << 1,
+	MANA_IB_UCNTX_RC_SQ_POW2_SUPPORT = 1 << 2,
 };
 
 struct mana_ib_alloc_ucontext_resp {
-- 
2.43.0