RDS: RDMA support
Some transports may support RDMA features. This handles the
non-transport-specific parts, like pinning user pages and
tracking mapped regions.
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/rdma.h b/net/rds/rdma.h
new file mode 100644
index 0000000..4255120
--- /dev/null
+++ b/net/rds/rdma.h
@@ -0,0 +1,84 @@
+#ifndef _RDS_RDMA_H
+#define _RDS_RDMA_H
+
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+#include <linux/scatterlist.h>
+
+#include "rds.h"
+
+struct rds_mr {
+ struct rb_node r_rb_node;
+ atomic_t r_refcount;
+ u32 r_key;
+
+ /* A copy of the creation flags */
+ unsigned int r_use_once:1;
+ unsigned int r_invalidate:1;
+ unsigned int r_write:1;
+
+ /* This is for RDS_MR_DEAD.
+ * It would be nice & consistent to make this part of the above
+ * bit field here, but we need to use test_and_set_bit.
+ */
+ unsigned long r_state;
+ struct rds_sock *r_sock; /* back pointer to the socket that owns us */
+ struct rds_transport *r_trans;
+ void *r_trans_private;
+};
+
+/* Flags for mr->r_state */
+#define RDS_MR_DEAD 0
+
+struct rds_rdma_op {
+ u32 r_key;
+ u64 r_remote_addr;
+ unsigned int r_write:1;
+ unsigned int r_fence:1;
+ unsigned int r_notify:1;
+ unsigned int r_recverr:1;
+ unsigned int r_mapped:1;
+ struct rds_notifier *r_notifier;
+ unsigned int r_bytes;
+ unsigned int r_nents;
+ unsigned int r_count;
+ struct scatterlist r_sg[0];
+};
+
+static inline rds_rdma_cookie_t rds_rdma_make_cookie(u32 r_key, u32 offset)
+{
+ return r_key | (((u64) offset) << 32);
+}
+
+static inline u32 rds_rdma_cookie_key(rds_rdma_cookie_t cookie)
+{
+ return cookie;
+}
+
+static inline u32 rds_rdma_cookie_offset(rds_rdma_cookie_t cookie)
+{
+ return cookie >> 32;
+}
+
+int rds_get_mr(struct rds_sock *rs, char __user *optval, int optlen);
+int rds_free_mr(struct rds_sock *rs, char __user *optval, int optlen);
+void rds_rdma_drop_keys(struct rds_sock *rs);
+int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
+ struct cmsghdr *cmsg);
+int rds_cmsg_rdma_dest(struct rds_sock *rs, struct rds_message *rm,
+ struct cmsghdr *cmsg);
+int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
+ struct cmsghdr *cmsg);
+int rds_cmsg_rdma_map(struct rds_sock *rs, struct rds_message *rm,
+ struct cmsghdr *cmsg);
+void rds_rdma_free_op(struct rds_rdma_op *ro);
+void rds_rdma_send_complete(struct rds_message *rm, int);
+
+extern void __rds_put_mr_final(struct rds_mr *mr);
+static inline void rds_mr_put(struct rds_mr *mr)
+{
+ if (atomic_dec_and_test(&mr->r_refcount))
+ __rds_put_mr_final(mr);
+}
+
+#endif