Revert "writeback: introduce writeback_control.more_io to indicate more io"

This reverts commit 2e6883bdf49abd0e7f0d9b6297fc3be7ebb2250b, as
requested by Fengguang Wu.  It's not quite fully baked yet, and while
there are patches around to fix the problems it caused, they should get
more testing.  Says Fengguang: "I'll resend them both for -mm later on,
in a more complete patchset".

See

	http://bugzilla.kernel.org/show_bug.cgi?id=9738

for some of this discussion.

Requested-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 3 insertions, 9 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 0fca82021d76..300324bd563c 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -482,8 +482,6 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc)
                 if (wbc->nr_to_write <= 0)
                         break;
         }
-        if (!list_empty(&sb->s_more_io))
-                wbc->more_io = 1;
         return;         /* Leave any unwritten inodes on s_io */
 }
 
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index bef7d66601cb..c6148bbf1250 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -62,7 +62,6 @@ struct writeback_control {
         unsigned for_reclaim:1;         /* Invoked from the page allocator */
         unsigned for_writepages:1;      /* This is a writepages() call */
         unsigned range_cyclic:1;        /* range_start is cyclic */
-        unsigned more_io:1;             /* more io to be dispatched */
 };
 
 /*
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index d55cfcae2ef1..3d3848fa6324 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -558,7 +558,6 @@ static void background_writeout(unsigned long _min_pages)
                         global_page_state(NR_UNSTABLE_NFS) < background_thresh
                                 && min_pages <= 0)
                         break;
-                wbc.more_io = 0;
                 wbc.encountered_congestion = 0;
                 wbc.nr_to_write = MAX_WRITEBACK_PAGES;
                 wbc.pages_skipped = 0;
@@ -566,9 +565,8 @@ static void background_writeout(unsigned long _min_pages)
                 min_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
                 if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) {
                         /* Wrote less than expected */
-                        if (wbc.encountered_congestion || wbc.more_io)
-                                congestion_wait(WRITE, HZ/10);
-                        else
+                        congestion_wait(WRITE, HZ/10);
+                        if (!wbc.encountered_congestion)
                                 break;
                 }
         }
@@ -633,12 +631,11 @@ static void wb_kupdate(unsigned long arg)
                         global_page_state(NR_UNSTABLE_NFS) +
                         (inodes_stat.nr_inodes - inodes_stat.nr_unused);
         while (nr_to_write > 0) {
-                wbc.more_io = 0;
                 wbc.encountered_congestion = 0;
                 wbc.nr_to_write = MAX_WRITEBACK_PAGES;
                 writeback_inodes(&wbc);
                 if (wbc.nr_to_write > 0) {
-                        if (wbc.encountered_congestion || wbc.more_io)
+                        if (wbc.encountered_congestion)
                                 congestion_wait(WRITE, HZ/10);
                         else
                                 break;  /* All the old data is written */