[PATCH 04/45] writeback: remove unused nonblocking and congestion checks

[Wu Fengguang <fengguang.wu@intel.com>]

[-- Attachment #1: writeback-remove-congested-checks.patch --]
[-- Type: text/plain, Size: 6095 bytes --]

- 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.

CC: Chris Mason <chris.mason@oracle.com>
CC: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 drivers/staging/pohmelfs/inode.c |    9 ---------
 fs/afs/write.c                   |   16 +---------------
 fs/cifs/file.c                   |   10 ----------
 fs/fs-writeback.c                |    8 --------
 fs/gfs2/aops.c                   |   10 ----------
 fs/xfs/linux-2.6/xfs_aops.c      |    6 +-----
 mm/page-writeback.c              |   12 ------------
 7 files changed, 2 insertions(+), 69 deletions(-)

--- linux.orig/fs/fs-writeback.c	2009-10-06 23:31:54.000000000 +0800
+++ linux/fs/fs-writeback.c	2009-10-06 23:31:59.000000000 +0800
@@ -660,14 +660,6 @@ static void writeback_inodes_wb(struct b
 			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.
--- linux.orig/mm/page-writeback.c	2009-10-06 23:31:54.000000000 +0800
+++ linux/mm/page-writeback.c	2009-10-06 23:31:59.000000000 +0800
@@ -787,7 +787,6 @@ int write_cache_pages(struct address_spa
 		      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;
@@ -800,11 +799,6 @@ int write_cache_pages(struct address_spa
 	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 */
@@ -923,12 +917,6 @@ continue_unlock:
 					break;
 				}
 			}
-
-			if (wbc->nonblocking && bdi_write_congested(bdi)) {
-				wbc->encountered_congestion = 1;
-				done = 1;
-				break;
-			}
 		}
 		pagevec_release(&pvec);
 		cond_resched();
--- linux.orig/drivers/staging/pohmelfs/inode.c	2009-10-06 23:31:41.000000000 +0800
+++ linux/drivers/staging/pohmelfs/inode.c	2009-10-06 23:31:59.000000000 +0800
@@ -152,11 +152,6 @@ static int pohmelfs_writepages(struct ad
 	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 +243,6 @@ 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:
--- linux.orig/fs/afs/write.c	2009-10-06 23:31:41.000000000 +0800
+++ linux/fs/afs/write.c	2009-10-06 23:31:59.000000000 +0800
@@ -455,8 +455,6 @@ int afs_writepage(struct page *page, str
 	}
 
 	wbc->nr_to_write -= ret;
-	if (wbc->nonblocking && bdi_write_congested(bdi))
-		wbc->encountered_congestion = 1;
 
 	_leave(" = 0");
 	return 0;
@@ -529,11 +527,6 @@ static int afs_writepages_region(struct 
 
 		wbc->nr_to_write -= ret;
 
-		if (wbc->nonblocking && bdi_write_congested(bdi)) {
-			wbc->encountered_congestion = 1;
-			break;
-		}
-
 		cond_resched();
 	} while (index < end && wbc->nr_to_write > 0);
 
@@ -554,18 +547,11 @@ int afs_writepages(struct address_space 
 
 	_enter("");
 
-	if (wbc->nonblocking && bdi_write_congested(bdi)) {
-		wbc->encountered_congestion = 1;
-		_leave(" = 0 [congest]");
-		return 0;
-	}
-
 	if (wbc->range_cyclic) {
 		start = mapping->writeback_index;
 		end = -1;
 		ret = afs_writepages_region(mapping, wbc, start, end, &next);
-		if (start > 0 && wbc->nr_to_write > 0 && ret == 0 &&
-		    !(wbc->nonblocking && wbc->encountered_congestion))
+		if (start > 0 && wbc->nr_to_write > 0 && ret == 0)
 			ret = afs_writepages_region(mapping, wbc, 0, start,
 						    &next);
 		mapping->writeback_index = next;
--- linux.orig/fs/cifs/file.c	2009-10-06 23:31:41.000000000 +0800
+++ linux/fs/cifs/file.c	2009-10-06 23:31:59.000000000 +0800
@@ -1379,16 +1379,6 @@ static int cifs_writepages(struct addres
 		return generic_writepages(mapping, wbc);
 
 
-	/*
-	 * BB: Is this meaningful for a non-block-device file system?
-	 * If it is, we should test it again after we do I/O
-	 */
-	if (wbc->nonblocking && bdi_write_congested(bdi)) {
-		wbc->encountered_congestion = 1;
-		kfree(iov);
-		return 0;
-	}
-
 	xid = GetXid();
 
 	pagevec_init(&pvec, 0);
--- linux.orig/fs/gfs2/aops.c	2009-10-06 23:31:41.000000000 +0800
+++ linux/fs/gfs2/aops.c	2009-10-06 23:31:59.000000000 +0800
@@ -313,11 +313,6 @@ static int gfs2_write_jdata_pagevec(stru
 
 		if (ret || (--(wbc->nr_to_write) <= 0))
 			ret = 1;
-		if (wbc->nonblocking && bdi_write_congested(bdi)) {
-			wbc->encountered_congestion = 1;
-			ret = 1;
-		}
-
 	}
 	gfs2_trans_end(sdp);
 	return ret;
@@ -348,11 +343,6 @@ static int gfs2_write_cache_jdata(struct
 	int scanned = 0;
 	int range_whole = 0;
 
-	if (wbc->nonblocking && bdi_write_congested(bdi)) {
-		wbc->encountered_congestion = 1;
-		return 0;
-	}
-
 	pagevec_init(&pvec, 0);
 	if (wbc->range_cyclic) {
 		index = mapping->writeback_index; /* Start from prev offset */
--- linux.orig/fs/xfs/linux-2.6/xfs_aops.c	2009-10-06 23:31:41.000000000 +0800
+++ linux/fs/xfs/linux-2.6/xfs_aops.c	2009-10-06 23:31:59.000000000 +0800
@@ -890,12 +890,8 @@ xfs_convert_page(
 
 			bdi = inode->i_mapping->backing_dev_info;
 			wbc->nr_to_write--;
-			if (bdi_write_congested(bdi)) {
-				wbc->encountered_congestion = 1;
+			if (wbc->nr_to_write <= 0)
 				done = 1;
-			} else if (wbc->nr_to_write <= 0) {
-				done = 1;
-			}
 		}
 		xfs_start_page_writeback(page, !page_dirty, count);
 	}