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>

1 files changed, 84 insertions, 0 deletions

diff --git a/net/rds/rdma.h b/net/rds/rdma.h
new file mode 100644
index 000000000000..425512098b0b
--- /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