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-rw-r--r--drivers/infiniband/core/user_mad.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c
index 840ede9ae96..208c7f34323 100644
--- a/drivers/infiniband/core/user_mad.c
+++ b/drivers/infiniband/core/user_mad.c
@@ -777,6 +777,19 @@ 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;