[patch] IB/rxe: fix error code in rxe_srq_from_init()

[Dan Carpenter]

If copy_to_user() fails then it returns the number of bytes not copied.
It would be between 1-4 here.  Later the callers dereference it leading
to an Oops.

It was sort of hard to fix this without making the code confusing so I
did a little cleanup.

Fixes: 443c15d23220 ('IB/rxe: Shared Receive Queue (SRQ) manipulation 
functions')
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>

diff --git a/drivers/infiniband/hw/rxe/rxe_srq.c 
b/drivers/infiniband/hw/rxe/rxe_srq.c
index 22c57d1..2a6e3cd 100644
--- a/drivers/infiniband/hw/rxe/rxe_srq.c
+++ b/drivers/infiniband/hw/rxe/rxe_srq.c
@@ -121,8 +121,7 @@ int rxe_srq_from_init(struct rxe_dev *rxe, struct rxe_srq 
*srq,
                           srq_wqe_size);
        if (!q) {
                pr_warn("unable to allocate queue for srq\n");
-               err = -ENOMEM;
-               goto err1;
+               return -ENOMEM;
        }
 
        srq->rq.queue = q;
@@ -130,15 +129,14 @@ int rxe_srq_from_init(struct rxe_dev *rxe, struct rxe_srq 
*srq,
        err = do_mmap_info(rxe, udata, false, context, q->buf,
                           q->buf_size, &q->ip);
        if (err)
-               goto err1;
+               return err;
 
-       if (udata && udata->outlen >= sizeof(struct mminfo) + sizeof(u32))
-               return copy_to_user(udata->outbuf + sizeof(struct mminfo),
-                       &srq->srq_num, sizeof(u32));
-       else
-               return 0;
-err1:
-       return err;
+       if (udata && udata->outlen >= sizeof(struct mminfo) + sizeof(u32)) {
+               if (copy_to_user(udata->outbuf + sizeof(struct mminfo),
+                                &srq->srq_num, sizeof(u32)))
+                       return -EFAULT;
+       }
+       return 0;
 }
 
 int rxe_srq_from_attr(struct rxe_dev *rxe, struct rxe_srq *srq,