writeback: remove unused nonblocking and congestion checks

- no one is calling wb_writeback and write_cache_pages with
  wbc.nonblocking=1 any more
- lumpy pageout will want to do nonblocking writeback without the
  congestion wait

So remove the congestion checks as suggested by Chris.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Alex Elder <aelder@sgi.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

4 files changed, 1 insertions, 39 deletions

diff --git a/drivers/staging/pohmelfs/inode.c b/drivers/staging/pohmelfs/inode.c
index c94de3139223..f69b7783027f 100644
--- a/drivers/staging/pohmelfs/inode.c
+++ b/drivers/staging/pohmelfs/inode.c
@@ -143,7 +143,6 @@ static int pohmelfs_writepages(struct address_space *mapping, struct writeback_c
         struct inode *inode = mapping->host;
         struct pohmelfs_inode *pi = POHMELFS_I(inode);
         struct pohmelfs_sb *psb = POHMELFS_SB(inode->i_sb);
-        struct backing_dev_info *bdi = mapping->backing_dev_info;
         int err = 0;
         int done = 0;
         int nr_pages;
@@ -152,11 +151,6 @@ static int pohmelfs_writepages(struct address_space *mapping, struct writeback_c
         int scanned = 0;
         int range_whole = 0;
 
-        if (wbc->nonblocking && bdi_write_congested(bdi)) {
-                wbc->encountered_congestion = 1;
-                return 0;
-        }
-
         if (wbc->range_cyclic) {
                 index = mapping->writeback_index; /* Start from prev offset */
                 end = -1;
@@ -248,10 +242,6 @@ retry:
 
                         if (wbc->nr_to_write <= 0)
                                 done = 1;
-                        if (wbc->nonblocking && bdi_write_congested(bdi)) {
-                                wbc->encountered_congestion = 1;
-                                done = 1;
-                        }
 
                         continue;
 out_continue:
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 0793961f7699..49bc1b8e8f19 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -639,14 +639,6 @@ static void writeback_inodes_wb(struct bdi_writeback *wb,
                         continue;
                 }
 
-                if (wbc->nonblocking && bdi_write_congested(wb->bdi)) {
-                        wbc->encountered_congestion = 1;
-                        if (!is_blkdev_sb)
-                                break;          /* Skip a congested fs */
-                        requeue_io(inode);
-                        continue;               /* Skip a congested blockdev */
-                }
-
                 /*
                  * Was this inode dirtied after sync_sb_inodes was called?
                  * This keeps sync from extra jobs and livelock.
@@ -770,7 +762,6 @@ static long wb_writeback(struct bdi_writeback *wb,
                         break;
 
                 wbc.more_io = 0;
-                wbc.encountered_congestion = 0;
                 wbc.nr_to_write = MAX_WRITEBACK_PAGES;
                 wbc.pages_skipped = 0;
                 writeback_inodes_wb(wb, &wbc);
diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index c2e30eea74dc..70f989895d15 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -904,16 +904,9 @@ xfs_convert_page(
 
         if (startio) {
                 if (count) {
-                        struct backing_dev_info *bdi;
-
-                        bdi = inode->i_mapping->backing_dev_info;
                         wbc->nr_to_write--;
-                        if (bdi_write_congested(bdi)) {
-                                wbc->encountered_congestion = 1;
-                                done = 1;
-                        } else if (wbc->nr_to_write <= 0) {
+                        if (wbc->nr_to_write <= 0)
                                 done = 1;
-                        }
                 }
                 xfs_start_page_writeback(page, !page_dirty, count);
         }
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 2c5d79236ead..0b19943ecf8b 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -821,7 +821,6 @@ int write_cache_pages(struct address_space *mapping,
                       struct writeback_control *wbc, writepage_t writepage,
                       void *data)
 {
-        struct backing_dev_info *bdi = mapping->backing_dev_info;
         int ret = 0;
         int done = 0;
         struct pagevec pvec;
@@ -834,11 +833,6 @@ int write_cache_pages(struct address_space *mapping,
         int range_whole = 0;
         long nr_to_write = wbc->nr_to_write;
 
-        if (wbc->nonblocking && bdi_write_congested(bdi)) {
-                wbc->encountered_congestion = 1;
-                return 0;
-        }
-
         pagevec_init(&pvec, 0);
         if (wbc->range_cyclic) {
                 writeback_index = mapping->writeback_index; /* prev offset */
@@ -957,12 +951,6 @@ continue_unlock:
                                         break;
                                 }
                         }
-
-                        if (wbc->nonblocking && bdi_write_congested(bdi)) {
-                                wbc->encountered_congestion = 1;
-                                done = 1;
-                                break;
-                        }
                 }
                 pagevec_release(&pvec);
                 cond_resched();