rxe: Fix a sleep-in-atomic bug in post_one_send

The driver may sleep under a spin lock, and the function call path is:
post_one_send (acquire the lock by spin_lock_irqsave)
  init_send_wqe
    copy_from_user --> may sleep

There is no flow that makes "qp->is_user" true, and copy_from_user may
cause bug when a non-user pointer is used. So the lines of copy_from_user
and check of "qp->is_user" are removed.

Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 2 insertions, 7 deletions

diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 83d709e74dfb..073e66783f1d 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -740,13 +740,8 @@ static int init_send_wqe(struct rxe_qp *qp, struct ib_send_wr *ibwr,
 
                 sge = ibwr->sg_list;
                 for (i = 0; i < num_sge; i++, sge++) {
-                        if (qp->is_user && copy_from_user(p, (__user void *)
-                                            (uintptr_t)sge->addr, sge->length))
-                                return -EFAULT;
-
-                        else if (!qp->is_user)
-                                memcpy(p, (void *)(uintptr_t)sge->addr,
-                                       sge->length);
+                        memcpy(p, (void *)(uintptr_t)sge->addr,
+                                        sge->length);
 
                         p += sge->length;
                 }