CIFS: SMBD: Implement RDMA memory registration
Memory registration is used for transferring payload via RDMA read or write.
After I/O is done, memory registrations are recovered and reused. This
process can be time consuming and is done in a work queue.
Signed-off-by: Long Li <longli@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
diff --git a/fs/cifs/smbdirect.h b/fs/cifs/smbdirect.h
index 27453ef..fdb8df8 100644
--- a/fs/cifs/smbdirect.h
+++ b/fs/cifs/smbdirect.h
@@ -90,6 +90,29 @@ struct smbd_connection {
int receive_credit_target;
int fragment_reassembly_remaining;
+ /* Memory registrations */
+ /* Maximum number of RDMA read/write outstanding on this connection */
+ int responder_resources;
+ /* Maximum number of SGEs in a RDMA write/read */
+ int max_frmr_depth;
+ /*
+ * If payload is less than or equal to the threshold,
+ * use RDMA send/recv to send upper layer I/O.
+ * If payload is more than the threshold,
+ * use RDMA read/write through memory registration for I/O.
+ */
+ int rdma_readwrite_threshold;
+ enum ib_mr_type mr_type;
+ struct list_head mr_list;
+ spinlock_t mr_list_lock;
+ /* The number of available MRs ready for memory registration */
+ atomic_t mr_ready_count;
+ atomic_t mr_used_count;
+ wait_queue_head_t wait_mr;
+ struct work_struct mr_recovery_work;
+ /* Used by transport to wait until all MRs are returned */
+ wait_queue_head_t wait_for_mr_cleanup;
+
/* Activity accoutning */
/* Pending reqeusts issued from upper layer */
int smbd_send_pending;
@@ -262,6 +285,36 @@ void smbd_destroy(struct smbd_connection *info);
int smbd_recv(struct smbd_connection *info, struct msghdr *msg);
int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst);
+enum mr_state {
+ MR_READY,
+ MR_REGISTERED,
+ MR_INVALIDATED,
+ MR_ERROR
+};
+
+struct smbd_mr {
+ struct smbd_connection *conn;
+ struct list_head list;
+ enum mr_state state;
+ struct ib_mr *mr;
+ struct scatterlist *sgl;
+ int sgl_count;
+ enum dma_data_direction dir;
+ union {
+ struct ib_reg_wr wr;
+ struct ib_send_wr inv_wr;
+ };
+ struct ib_cqe cqe;
+ bool need_invalidate;
+ struct completion invalidate_done;
+};
+
+/* Interfaces to register and deregister MR for RDMA read/write */
+struct smbd_mr *smbd_register_mr(
+ struct smbd_connection *info, struct page *pages[], int num_pages,
+ int tailsz, bool writing, bool need_invalidate);
+int smbd_deregister_mr(struct smbd_mr *mr);
+
#else
#define cifs_rdma_enabled(server) 0
struct smbd_connection {};