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>

3 files changed, 46 insertions, 0 deletions

diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index 89c798e..3372d67 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 4cbef8c..38a66fb 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 91e4750..ff092a0 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,
 };