IB/uverbs: Support for query SRQ from userspace

Add support to uverbs to handle querying userspace SRQs (shared
receive queues), including adding an ABI for marshalling requests and
responses.  The kernel midlayer already has the underlying
ib_query_srq() function.
Signed-off-by: Dotan Barak <dotanb@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/uverbs.h

@@ -195,6 +195,7 @@ IB_UVERBS_DECLARE_CMD(attach_mcast);
 IB_UVERBS_DECLARE_CMD(detach_mcast);
 IB_UVERBS_DECLARE_CMD(create_srq);
 IB_UVERBS_DECLARE_CMD(modify_srq);
+IB_UVERBS_DECLARE_CMD(query_srq);
 IB_UVERBS_DECLARE_CMD(destroy_srq);
 
 #endif /* UVERBS_H */

drivers/infiniband/core/uverbs_cmd.c

@@ -2,6 +2,7 @@
  * Copyright (c) 2005 Topspin Communications.  All rights reserved.
  * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
  * Copyright (c) 2005 PathScale, Inc.  All rights reserved.
+ * Copyright (c) 2006 Mellanox Technologies.  All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
@@ -1923,6 +1924,49 @@ out:
 	return ret ? ret : in_len;
 }
 
+ssize_t ib_uverbs_query_srq(struct ib_uverbs_file *file,
+			    const char __user *buf,
+			    int in_len, int out_len)
+{
+	struct ib_uverbs_query_srq      cmd;
+	struct ib_uverbs_query_srq_resp resp;
+	struct ib_srq_attr              attr;
+	struct ib_srq                   *srq;
+	int                             ret;
+
+	if (out_len < sizeof resp)
+		return -ENOSPC;
+
+	if (copy_from_user(&cmd, buf, sizeof cmd))
+		return -EFAULT;
+
+	mutex_lock(&ib_uverbs_idr_mutex);
+
+	srq = idr_find(&ib_uverbs_srq_idr, cmd.srq_handle);
+	if (srq && srq->uobject->context == file->ucontext)
+		ret = ib_query_srq(srq, &attr);
+	else
+		ret = -EINVAL;
+
+	mutex_unlock(&ib_uverbs_idr_mutex);
+
+	if (ret)
+		goto out;
+
+	memset(&resp, 0, sizeof resp);
+
+	resp.max_wr    = attr.max_wr;
+	resp.max_sge   = attr.max_sge;
+	resp.srq_limit = attr.srq_limit;
+
+	if (copy_to_user((void __user *) (unsigned long) cmd.response,
+			 &resp, sizeof resp))
+		ret = -EFAULT;
+
+out:
+	return ret ? ret : in_len;
+}
+
 ssize_t ib_uverbs_destroy_srq(struct ib_uverbs_file *file,
 			      const char __user *buf, int in_len,
 			      int out_len)

drivers/infiniband/core/uverbs_main.c

@@ -108,6 +108,7 @@ static ssize_t (*uverbs_cmd_table[])(struct ib_uverbs_file *file,
 	[IB_USER_VERBS_CMD_DETACH_MCAST]  	= ib_uverbs_detach_mcast,
 	[IB_USER_VERBS_CMD_CREATE_SRQ]    	= ib_uverbs_create_srq,
 	[IB_USER_VERBS_CMD_MODIFY_SRQ]    	= ib_uverbs_modify_srq,
+	[IB_USER_VERBS_CMD_QUERY_SRQ]     	= ib_uverbs_query_srq,
 	[IB_USER_VERBS_CMD_DESTROY_SRQ]   	= ib_uverbs_destroy_srq,
 };
 

include/rdma/ib_user_verbs.h

@@ -2,6 +2,7 @@
  * Copyright (c) 2005 Topspin Communications.  All rights reserved.
  * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
  * Copyright (c) 2005 PathScale, Inc.  All rights reserved.
+ * Copyright (c) 2006 Mellanox Technologies.  All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
@@ -613,6 +614,20 @@ struct ib_uverbs_modify_srq {
 	__u64 driver_data[0];
 };
 
+struct ib_uverbs_query_srq {
+	__u64 response;
+	__u32 srq_handle;
+	__u32 reserved;
+	__u64 driver_data[0];
+};
+
+struct ib_uverbs_query_srq_resp {
+	__u32 max_wr;
+	__u32 max_sge;
+	__u32 srq_limit;
+	__u32 reserved;
+};
+
 struct ib_uverbs_destroy_srq {
 	__u64 response;
 	__u32 srq_handle;