bdi: separate out congested state into a separate struct
authorTejun Heo <tj@kernel.org>
Fri, 22 May 2015 21:13:35 +0000 (17:13 -0400)
committerJens Axboe <axboe@fb.com>
Tue, 2 Jun 2015 14:33:35 +0000 (08:33 -0600)
commit4aa9c692e052cf6db99db62a8fe0543e5c455da7
tree378d5b44e7ec769dd4dfc9ac5ab2447fdb1f50a4
parent8395cd9f813d5d7ed9870e642230acfcfc1e8a0a
bdi: separate out congested state into a separate struct

Currently, a wb's (bdi_writeback) congestion state is carried in its
->state field; however, cgroup writeback support will require multiple
wb's sharing the same congestion state.  This patch separates out
congestion state into its own struct - struct bdi_writeback_congested.
A new field wb field, wb_congested, points to its associated congested
struct.  The default wb, bdi->wb, always points to bdi->wb_congested.

While this patch adds a layer of indirection, it doesn't introduce any
behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
include/linux/backing-dev-defs.h
include/linux/backing-dev.h
mm/backing-dev.c