RDS: Do not call set_page_dirty() with irqs off

set_page_dirty() unconditionally re-enables interrupts, so
if we call it with irqs off, they will be on after the call,
and that's bad. This patch moves the call after we've re-enabled
interrupts in send_drop_to(), so it's safe.

Also, add BUG_ONs to let us know if we ever do call set_page_dirty
with interrupts off.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 12 insertions, 7 deletions

diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c
index 65e668defe42..cfb1d904ed00 100644
--- a/net/rds/ib_rdma.c
+++ b/net/rds/ib_rdma.c
@@ -440,6 +440,7 @@ static void __rds_ib_teardown_mr(struct rds_ib_mr *ibmr)
 
                         /* FIXME we need a way to tell a r/w MR
                          * from a r/o MR */
+                        BUG_ON(in_interrupt());
                         set_page_dirty(page);
                         put_page(page);
                 }
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index 4c64daa1f5d5..61b359d9dffd 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -438,8 +438,10 @@ void rds_rdma_free_op(struct rds_rdma_op *ro)
                 /* Mark page dirty if it was possibly modified, which
                  * is the case for a RDMA_READ which copies from remote
                  * to local memory */
-                if (!ro->r_write)
+                if (!ro->r_write) {
+                        BUG_ON(in_interrupt());
                         set_page_dirty(page);
+                }
                 put_page(page);
         }
 
diff --git a/net/rds/send.c b/net/rds/send.c
index 51e2def50b12..4629a0b63bbd 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -507,12 +507,13 @@ EXPORT_SYMBOL_GPL(rds_send_get_message);
  */
 void rds_send_remove_from_sock(struct list_head *messages, int status)
 {
-        unsigned long flags = 0; /* silence gcc :P */
+        unsigned long flags;
         struct rds_sock *rs = NULL;
         struct rds_message *rm;
 
-        local_irq_save(flags);
         while (!list_empty(messages)) {
+                int was_on_sock = 0;
+
                 rm = list_entry(messages->next, struct rds_message,
                                 m_conn_item);
                 list_del_init(&rm->m_conn_item);
@@ -527,7 +528,7 @@ void rds_send_remove_from_sock(struct list_head *messages, int status)
                  * while we're messing with it. It does not prevent the
                  * message from being removed from the socket, though.
                  */
-                spin_lock(&rm->m_rs_lock);
+                spin_lock_irqsave(&rm->m_rs_lock, flags);
                 if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
                         goto unlock_and_drop;
 
@@ -556,21 +557,22 @@ void rds_send_remove_from_sock(struct list_head *messages, int status)
                                         notifier->n_status = status;
                                 rm->m_rdma_op->r_notifier = NULL;
                         }
-                        rds_message_put(rm);
+                        was_on_sock = 1;
                         rm->m_rs = NULL;
                 }
                 spin_unlock(&rs->rs_lock);
 
 unlock_and_drop:
-                spin_unlock(&rm->m_rs_lock);
+                spin_unlock_irqrestore(&rm->m_rs_lock, flags);
                 rds_message_put(rm);
+                if (was_on_sock)
+                        rds_message_put(rm);
         }
 
         if (rs) {
                 rds_wake_sk_sleep(rs);
                 sock_put(rds_rs_to_sk(rs));
         }
-        local_irq_restore(flags);
 }
 
 /*