userfaultfd: call handle_userfault() for userfaultfd_missing() faults

[cascardo/linux.git] / drivers / tty / tty_buffer.c

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 4cf263d..5a3fa89 100644 (file)
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -291,12 +291,11 @@ static int __tty_buffer_request_room(struct tty_port *port, size_t size,
                        n->flags = flags;
                        buf->tail = n;
                        b->commit = b->used;
-                       /* paired w/ barrier in flush_to_ldisc(); ensures the
+                       /* paired w/ acquire in flush_to_ldisc(); ensures the
                         * latest commit value can be read before the head is
                         * advanced to the next buffer
                         */
-                       smp_wmb();
-                       b->next = n;
+                       smp_store_release(&b->next, n);
                } else if (change)
                        size = 0;
                else
@@ -445,7 +444,6 @@ receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count)
                if (count)
                        disc->ops->receive_buf(tty, p, f, count);
        }
-       head->read += count;
        return count;
 }
 
@@ -488,12 +486,11 @@ static void flush_to_ldisc(struct work_struct *work)
                if (atomic_read(&buf->priority))
                        break;
 
-               next = head->next;
-               /* paired w/ barrier in __tty_buffer_request_room();
+               /* paired w/ release in __tty_buffer_request_room();
                 * ensures commit value read is not stale if the head
                 * is advancing to the next buffer
                 */
-               smp_rmb();
+               next = smp_load_acquire(&head->next);
                count = head->commit - head->read;
                if (!count) {
                        if (next == NULL) {
@@ -508,6 +505,7 @@ static void flush_to_ldisc(struct work_struct *work)
                count = receive_buf(tty, head, count);
                if (!count)
                        break;
+               head->read += count;
        }
 
        mutex_unlock(&buf->lock);