[patch] goldfish: locking bugs in goldfish_pipe_read_write()

[Dan Carpenter]

We recently messed up the error handling here.  We can return with the
pipe->lock held or sometimes we unlock twice by mistake.

Fixes: 2f3be88237a3 ('goldfish_pipe: Pin pages to memory while copying and 
other cleanups')
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>

diff --git a/drivers/platform/goldfish/goldfish_pipe.c 
b/drivers/platform/goldfish/goldfish_pipe.c
index e3fab9a..839df4a 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -313,7 +313,7 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, 
char __user *buffer,
                                     !is_write, 0, &page, NULL);
                up_read(&current->mm->mmap_sem);
                if (ret < 0)
-                       return ret;
+                       break;
 
                if (dev->version) {
                        /* Device version 1 or newer (qemu-android) expects the
@@ -400,22 +400,16 @@ static ssize_t goldfish_pipe_read_write(struct file 
*filp, char __user *buffer,
                while (test_bit(wakeBit, &pipe->flags)) {
                        if (wait_event_interruptible(
                                        pipe->wake_queue,
-                                       !test_bit(wakeBit, &pipe->flags))) {
-                               ret = -ERESTARTSYS;
-                               break;
-                       }
-
-                       if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags)) {
-                               ret = -EIO;
-                               break;
-                       }
+                                       !test_bit(wakeBit, &pipe->flags)))
+                               return -ERESTARTSYS;
+
+                       if (test_bit(BIT_CLOSED_ON_HOST, &pipe->flags))
+                               return -EIO;
                }
 
                /* Try to re-acquire the lock */
-               if (mutex_lock_interruptible(&pipe->lock)) {
-                       ret = -ERESTARTSYS;
-                       break;
-               }
+               if (mutex_lock_interruptible(&pipe->lock))
+                       return -ERESTARTSYS;
        }
        mutex_unlock(&pipe->lock);