dax: bdev_direct_access() may sleep
dax: bdev_direct_access() may sleep

The brd driver is the only in-tree driver that may sleep currently.
After some discussion on linux-fsdevel, we decided that any driver
may choose to sleep in its ->direct_access method.  To ensure that all
callers of bdev_direct_access() are prepared for this, add a call
to might_sleep().

Signed-off-by: Matthew Wilcox <ed1245e46949b7b8f2bca25d41520ebc8aeefcf8@intel.com>
Signed-off-by: Al Viro <de609eb4d5d70b1d38ec6642adbfc33a2781f63c@zeniv.linux.org.uk>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs