[PATCH rdma-next v3 07/17] RDMA/uverbs: Add CQ buffer UMEM attribute and driver helpers

[Jiri Pirko <jiri@resnulli.us>]

From: Jiri Pirko <jiri@nvidia.com>

Add UVERBS_ATTR_CREATE_CQ_BUF_UMEM and two driver-facing
wrappers, ib_umem_get_cq_buf() and ib_umem_get_cq_buf_or_va(),
that pin a CQ buffer umem from it. The wrappers reuse the
existing legacy CQ buffer-attr filler.

Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
v2->v3:
- new patch
---
 drivers/infiniband/core/umem.c                | 48 +++++++++++++++++++
 drivers/infiniband/core/uverbs_std_types_cq.c |  2 +
 include/rdma/ib_umem.h                        | 19 ++++++++
 include/uapi/rdma/ib_user_ioctl_cmds.h        |  1 +
 4 files changed, 70 insertions(+)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index f720de8cb162..04684411c82e 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -427,6 +427,54 @@ static int uverbs_create_cq_get_buffer_desc(struct uverbs_attr_bundle *attrs,
 	return -ENODATA;
 }
 
+/**
+ * ib_umem_get_cq_buf - Pin a CQ buffer umem from per-command attributes.
+ * @device:  IB device.
+ * @udata:   uverbs udata bundle (may be NULL).
+ * @size:    minimum required CQ buffer length.
+ * @access:  IB access flags.
+ *
+ * Resolves the CQ buffer from the new UMEM attribute or the legacy
+ * CQ buffer attributes. There is no UHW VA fallback, so the caller
+ * must arrange its own backing (typically an in-kernel allocation)
+ * when no source is available.
+ *
+ * Return: caller-owned umem on success; NULL when no source supplied
+ * a buffer; ERR_PTR(...) on error.
+ */
+struct ib_umem *ib_umem_get_cq_buf(struct ib_device *device,
+				   struct ib_udata *udata, size_t size,
+				   int access)
+{
+	return ib_umem_get(device, udata, UVERBS_ATTR_CREATE_CQ_BUF_UMEM,
+			   uverbs_create_cq_get_buffer_desc, false, 0,
+			   size, access);
+}
+EXPORT_SYMBOL(ib_umem_get_cq_buf);
+
+/**
+ * ib_umem_get_cq_buf_or_va - Pin a CQ buffer umem with UHW VA fallback.
+ * @device:  IB device.
+ * @udata:   uverbs udata bundle (may be NULL).
+ * @addr:    UHW user VA used when no per-command attribute matched.
+ * @size:    minimum required CQ buffer length.
+ * @access:  IB access flags.
+ *
+ * Like ib_umem_get_cq_buf(), but pins @addr/@size when neither the
+ * UMEM attribute nor the legacy CQ buffer attributes are supplied.
+ *
+ * Return: caller-owned umem on success, ERR_PTR(...) on error.
+ */
+struct ib_umem *ib_umem_get_cq_buf_or_va(struct ib_device *device,
+					 struct ib_udata *udata, u64 addr,
+					 size_t size, int access)
+{
+	return ib_umem_get(device, udata, UVERBS_ATTR_CREATE_CQ_BUF_UMEM,
+			   uverbs_create_cq_get_buffer_desc, true, addr,
+			   size, access);
+}
+EXPORT_SYMBOL(ib_umem_get_cq_buf_or_va);
+
 /**
  * ib_umem_get_cq_tmp - Temporary CQ buffer umem getter.
  * @device: IB device.
diff --git a/drivers/infiniband/core/uverbs_std_types_cq.c b/drivers/infiniband/core/uverbs_std_types_cq.c
index 711bad0aa8a3..05d1294762c0 100644
--- a/drivers/infiniband/core/uverbs_std_types_cq.c
+++ b/drivers/infiniband/core/uverbs_std_types_cq.c
@@ -215,6 +215,8 @@ DECLARE_UVERBS_NAMED_METHOD(
 	UVERBS_ATTR_PTR_IN(UVERBS_ATTR_CREATE_CQ_BUFFER_OFFSET,
 			   UVERBS_ATTR_TYPE(u64),
 			   UA_OPTIONAL),
+	UVERBS_ATTR_UMEM(UVERBS_ATTR_CREATE_CQ_BUF_UMEM,
+			 UA_OPTIONAL),
 	UVERBS_ATTR_UHW());
 
 static int UVERBS_HANDLER(UVERBS_METHOD_CQ_DESTROY)(
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index afe12a1bedb0..174788a0640d 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -92,6 +92,12 @@ struct ib_umem *ib_umem_get(struct ib_device *device, struct ib_udata *udata,
 			    u16 attr_id,
 			    ib_umem_buf_desc_filler_t legacy_filler,
 			    bool va_fallback, u64 addr, size_t size, int access);
+struct ib_umem *ib_umem_get_cq_buf(struct ib_device *device,
+				   struct ib_udata *udata, size_t size,
+				   int access);
+struct ib_umem *ib_umem_get_cq_buf_or_va(struct ib_device *device,
+					 struct ib_udata *udata, u64 addr,
+					 size_t size, int access);
 struct ib_umem *ib_umem_get_cq_tmp(struct ib_device *device,
 				   struct uverbs_attr_bundle *attrs);
 
@@ -208,6 +214,19 @@ ib_umem_get(struct ib_device *device, struct ib_udata *udata, u16 attr_id,
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
+static inline struct ib_umem *ib_umem_get_cq_buf(struct ib_device *device,
+						 struct ib_udata *udata,
+						 size_t size, int access)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+static inline struct ib_umem *ib_umem_get_cq_buf_or_va(struct ib_device *device,
+						       struct ib_udata *udata,
+						       u64 addr, size_t size,
+						       int access)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
 static inline struct ib_umem *
 ib_umem_get_cq_tmp(struct ib_device *device, struct uverbs_attr_bundle *attrs)
 {
diff --git a/include/uapi/rdma/ib_user_ioctl_cmds.h b/include/uapi/rdma/ib_user_ioctl_cmds.h
index 72041c1b0ea5..02835b7fd76d 100644
--- a/include/uapi/rdma/ib_user_ioctl_cmds.h
+++ b/include/uapi/rdma/ib_user_ioctl_cmds.h
@@ -117,6 +117,7 @@ enum uverbs_attrs_create_cq_cmd_attr_ids {
 	UVERBS_ATTR_CREATE_CQ_BUFFER_LENGTH,
 	UVERBS_ATTR_CREATE_CQ_BUFFER_FD,
 	UVERBS_ATTR_CREATE_CQ_BUFFER_OFFSET,
+	UVERBS_ATTR_CREATE_CQ_BUF_UMEM,
 };
 
 enum uverbs_attrs_destroy_cq_cmd_attr_ids {
-- 
2.53.0