f2fs: fix the starvation problem on cp_rwsem

This patch removes the logic previously introduced to address the starvation
on cp_rwsem.

One potential there-in bug is that we should cover the wait.list with spin_lock,
but the previous code broke this rule.

And, actually current rwsem handles this starvation issue reasonably, so that we
didn't need to do this before neither.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

2 files changed, 0 insertions, 14 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a955a59dfdbe..308967b71674 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -18,8 +18,6 @@
 #include <linux/crc32.h>
 #include <linux/magic.h>
 #include <linux/kobject.h>
-#include <linux/wait.h>
-#include <linux/sched.h>
 
 /*
  * For mount options
@@ -360,7 +358,6 @@ struct f2fs_sb_info {
         struct inode *meta_inode;               /* cache meta blocks */
         struct mutex cp_mutex;                  /* checkpoint procedure lock */
         struct rw_semaphore cp_rwsem;           /* blocking FS operations */
-        wait_queue_head_t cp_wait;              /* checkpoint wait queue */
         struct mutex node_write;                /* locking node writes */
         struct mutex writepages;                /* mutex for writepages() */
         int por_doing;                          /* recovery is doing or not */
@@ -516,13 +513,6 @@ static inline void clear_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f)
 
 static inline void f2fs_lock_op(struct f2fs_sb_info *sbi)
 {
-        /*
-         * If the checkpoint thread is waiting for cp_rwsem, add cuurent task
-         * into wait list to avoid the checkpoint thread starvation
-         */
-        while (!list_empty(&sbi->cp_rwsem.wait_list))
-                wait_event_interruptible(sbi->cp_wait,
-                                list_empty(&sbi->cp_rwsem.wait_list));
         down_read(&sbi->cp_rwsem);
 }
 
@@ -539,9 +529,6 @@ static inline void f2fs_lock_all(struct f2fs_sb_info *sbi)
 static inline void f2fs_unlock_all(struct f2fs_sb_info *sbi)
 {
         up_write(&sbi->cp_rwsem);
-
-        /* wake up all tasks blocked by checkpoint */
-        wake_up_all(&sbi->cp_wait);
 }
 
 /*
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 539c009d4138..3b786c85b5cd 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -841,7 +841,6 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
         spin_lock_init(&sbi->stat_lock);
         init_rwsem(&sbi->bio_sem);
         init_rwsem(&sbi->cp_rwsem);
-        init_waitqueue_head(&sbi->cp_wait);
         init_sb_info(sbi);
 
         /* get an inode for meta space */