n_r3964: fix lock imbalance

There is omitted BKunL in r3964_read.

Centralize the paths to one point with one unlock.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/char/n_r3964.c b/drivers/char/n_r3964.c
index d2e93e3..2e99158 100644 (file)
--- a/drivers/char/n_r3964.c
+++ b/drivers/char/n_r3964.c
@@ -1062,7 +1062,7 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
        struct r3964_client_info *pClient;
        struct r3964_message *pMsg;
        struct r3964_client_message theMsg;
-       int count;
+       int ret;
 
        TRACE_L("read()");
 
@@ -1074,8 +1074,8 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
                if (pMsg == NULL) {
                        /* no messages available. */
                        if (file->f_flags & O_NONBLOCK) {
-                               unlock_kernel();
-                               return -EAGAIN;
+                               ret = -EAGAIN;
+                               goto unlock;
                        }
                        /* block until there is a message: */
                        wait_event_interruptible(pInfo->read_wait,
@@ -1085,29 +1085,31 @@ static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
                /* If we still haven't got a message, we must have been signalled */
 
                if (!pMsg) {
-                       unlock_kernel();
-                       return -EINTR;
+                       ret = -EINTR;
+                       goto unlock;
                }
 
                /* deliver msg to client process: */
                theMsg.msg_id = pMsg->msg_id;
                theMsg.arg = pMsg->arg;
                theMsg.error_code = pMsg->error_code;
-               count = sizeof(struct r3964_client_message);
+               ret = sizeof(struct r3964_client_message);
 
                kfree(pMsg);
                TRACE_M("r3964_read - msg kfree %p", pMsg);
 
-               if (copy_to_user(buf, &theMsg, count)) {
-                       unlock_kernel();
-                       return -EFAULT;
+               if (copy_to_user(buf, &theMsg, ret)) {
+                       ret = -EFAULT;
+                       goto unlock;
                }
 
-               TRACE_PS("read - return %d", count);
-               return count;
+               TRACE_PS("read - return %d", ret);
+               goto unlock;
        }
+       ret = -EPERM;
+unlock:
        unlock_kernel();
-       return -EPERM;
+       return ret;
 }
 
 static ssize_t r3964_write(struct tty_struct *tty, struct file *file,