Merge branch 'linus' into x86/x2apic

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c
index 840ede9ae96..268a2d23b7c 100644
--- a/drivers/infiniband/core/user_mad.c
+++ b/drivers/infiniband/core/user_mad.c
@@ -31,8 +31,6 @@
  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
- *
- * $Id: user_mad.c 5596 2006-03-03 01:00:07Z sean.hefty $
  */
 
 #include <linux/module.h>
@@ -777,6 +775,19 @@ static long ib_umad_compat_ioctl(struct file *filp, unsigned int cmd,
 }
 #endif
 
+/*
+ * ib_umad_open() does not need the BKL:
+ *
+ *  - umad_port[] accesses are protected by port_lock, the
+ *    ib_umad_port structures are properly reference counted, and
+ *    everything else is purely local to the file being created, so
+ *    races against other open calls are not a problem;
+ *  - the ioctl method does not affect any global state outside of the
+ *    file structure being operated on;
+ *  - the port is added to umad_port[] as the last part of module
+ *    initialization so the open method will either immediately run
+ *    -ENXIO, or all required initialization will be done.
+ */
 static int ib_umad_open(struct inode *inode, struct file *filp)
 {
 	struct ib_umad_port *port;