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>

4 files changed, 61 insertions, 0 deletions

diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index 89c798eb57491f..3372d67ff139eb 100644
--- a/drivers/infiniband/core/uverbs.h
+++ b/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 */
diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 4cbef8c0663411..38a66fbef36db5 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/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)
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 91e4750fa3194b..ff092a0a94da0e 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/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,
 };
 
diff --git a/include/rdma/ib_user_verbs.h b/include/rdma/ib_user_verbs.h
index 58662c34a3de80..0edd3a6fe8f5f9 100644
--- a/include/rdma/ib_user_verbs.h
+++ b/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;