From: Leon Romanovsky <leonro@mellanox.com>
Date: Wed, 21 Feb 2018 18:12:39 +0200
Subject: RDMA/uverbs: Move uncontext check before SRCU read lock
Patch-mainline: v4.17-rc1
Git-commit: 491d5c6a3023e303cc693b91d9b3a4d54471c944
References: bsc#1103992 FATE#326009

There is no need to take SRCU lock before checking
file->ucontext, so move it do it before it.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/core/uverbs_main.c |   15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -705,6 +705,10 @@ static ssize_t ib_uverbs_write(struct fi
 	if (ret)
 		return ret;
 
+	if (!file->ucontext &&
+	    (command != IB_USER_VERBS_CMD_GET_CONTEXT || extended))
+		return -EINVAL;
+
 	if (extended && count < (sizeof(hdr) + sizeof(ex_hdr)))
 		return -EINVAL;
 
@@ -721,12 +725,6 @@ static ssize_t ib_uverbs_write(struct fi
 		goto out;
 	}
 
-	if (!file->ucontext &&
-	    command != IB_USER_VERBS_CMD_GET_CONTEXT) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	if (!extended) {
 		if (hdr.in_words * 4 != count) {
 			ret = -EINVAL;
@@ -742,11 +740,6 @@ static ssize_t ib_uverbs_write(struct fi
 		struct ib_udata uhw;
 		size_t written_count = count;
 
-		if (!file->ucontext) {
-			ret = -EINVAL;
-			goto out;
-		}
-
 		if (copy_from_user(&ex_hdr, buf + sizeof(hdr), sizeof(ex_hdr))) {
 			ret = -EFAULT;
 			goto out;