Merge branch 'akpm' (rest of patches from Andrew)
Merge the left-over patches from Andrew Morton.
This merges the remaining two patches from Andrew's pile of "little bit
more MM". I mulled it over, and we emailed back and forth with Josef,
and he pointed out where I was wrong.
Rule #51 of kernel maintenance: when somebody makes it clear that they
know the code better than you did, stop arguing and just apply the damn
patch.
Add a third patch by me to add a comment for the case that I had thought
was buggy and Josef corrected me on.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
filemap: add a comment about FAULT_FLAG_RETRY_NOWAIT behavior
filemap: drop the mmap_sem for all blocking operations
filemap: kill page_cache_read usage in filemap_fault
