RDS: Implement atomic operations
Implement a CMSG-based interface to do FADD and CSWP ops.
Alter send routines to handle atomic ops.
Add atomic counters to stats.
Add xmit_atomic() to struct rds_transport
Inline rds_ib_send_unmap_rdma into unmap_rm
Signed-off-by: Andy Grover <andy.grover@oracle.com>
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 4fda330..a7019df 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -719,3 +719,76 @@
return __rds_rdma_map(rs, CMSG_DATA(cmsg), &rm->m_rdma_cookie, &rm->rdma.m_rdma_mr);
}
+
+/*
+ * Fill in rds_message for an atomic request.
+ */
+int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm,
+ struct cmsghdr *cmsg)
+{
+ struct page *page = NULL;
+ struct rds_atomic_args *args;
+ int ret = 0;
+
+ if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_atomic_args))
+ || rm->atomic.op_active)
+ return -EINVAL;
+
+ args = CMSG_DATA(cmsg);
+
+ if (cmsg->cmsg_type == RDS_CMSG_ATOMIC_CSWP) {
+ rm->atomic.op_type = RDS_ATOMIC_TYPE_CSWP;
+ rm->atomic.op_swap_add = args->cswp.swap;
+ rm->atomic.op_compare = args->cswp.compare;
+ } else {
+ rm->atomic.op_type = RDS_ATOMIC_TYPE_FADD;
+ rm->atomic.op_swap_add = args->fadd.add;
+ }
+
+ rm->m_rdma_cookie = args->cookie;
+ rm->atomic.op_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME);
+ rm->atomic.op_recverr = rs->rs_recverr;
+ rm->atomic.op_sg = rds_message_alloc_sgs(rm, 1);
+
+ /* verify 8 byte-aligned */
+ if (args->local_addr & 0x7) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ ret = rds_pin_pages(args->local_addr, 1, &page, 1);
+ if (ret != 1)
+ goto err;
+ ret = 0;
+
+ sg_set_page(rm->atomic.op_sg, page, 8, offset_in_page(args->local_addr));
+
+ if (rm->atomic.op_notify || rm->atomic.op_recverr) {
+ /* We allocate an uninitialized notifier here, because
+ * we don't want to do that in the completion handler. We
+ * would have to use GFP_ATOMIC there, and don't want to deal
+ * with failed allocations.
+ */
+ rm->atomic.op_notifier = kmalloc(sizeof(*rm->atomic.op_notifier), GFP_KERNEL);
+ if (!rm->atomic.op_notifier) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ rm->atomic.op_notifier->n_user_token = args->user_token;
+ rm->atomic.op_notifier->n_status = RDS_RDMA_SUCCESS;
+ }
+
+ rm->atomic.op_rkey = rds_rdma_cookie_key(rm->m_rdma_cookie);
+ rm->atomic.op_remote_addr = args->remote_addr + rds_rdma_cookie_offset(args->cookie);
+
+ rm->atomic.op_active = 1;
+
+ return ret;
+err:
+ if (page)
+ put_page(page);
+ kfree(rm->atomic.op_notifier);
+
+ return ret;
+}