Q: Swap Locking Reinstatement

[ebiederm+eric@npwt.net (Eric W. Biederman)]

Recently the swap lockmap has been readded.

Was that just as a low cost sanity check, to use especially while
there were bugs in some of the low level disk drivers?

Was there something that really needs the swap lockmap?

The reason I am asking is that this causes conflicts with my shmfs
kernel patches.  I directly read/write swap pages through a variation
of rw_swap_page, and during I/O they must stay in the page cache, but
_not_ on the swapper inode, and the way the swap lockmap is currently
implemented causes a problem.

Eric