writeback: harmonize writeback threads naming

The write-back code mixes words "thread" and "task" for the same things. This
is not a big deal, but still an inconsistency.

hch: a convention I tend to use and I've seen in various places
is to always use _task for the storage of the task_struct pointer,
and thread everywhere else.  This especially helps with having
foo_thread for the actual thread and foo_task for a global
variable keeping the task_struct pointer

This patch renames:
* 'bdi_add_default_flusher_task()' -> 'bdi_add_default_flusher_thread()'
* 'bdi_forker_task()'              -> 'bdi_forker_thread()'

because bdi threads are 'bdi_writeback_thread()', so these names are more
consistent.

This patch also amends commentaries and makes them refer the forker and bdi
threads as "thread", not "task".

Also, while on it, make 'bdi_add_default_flusher_thread()' declaration use
'static void' instead of 'void static' and make checkpatch.pl happy.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

3 files changed, 15 insertions, 15 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 261570deb22c..002be0ff2ab3 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -840,7 +840,7 @@ int bdi_writeback_thread(void *data)
 
                         /*
                          * Longest period of inactivity that we tolerate. If we
-                         * see dirty data again later, the task will get
+                         * see dirty data again later, the thread will get
                          * recreated automatically.
                          */
                         max_idle = max(5UL * 60 * HZ, wait_jiffies);
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index e536f3a74e60..f0936f5f85dd 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -50,7 +50,7 @@ struct bdi_writeback {
 
         unsigned long last_old_flush;           /* last old data flush */
 
-        struct task_struct      *task;          /* writeback task */
+        struct task_struct      *task;          /* writeback thread */
         struct list_head        b_dirty;        /* dirty inodes */
         struct list_head        b_io;           /* parked for writeback */
         struct list_head        b_more_io;      /* parked for more writeback */
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index ac78a3336181..4e9ed2a8521f 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -50,7 +50,7 @@ static struct timer_list sync_supers_timer;
 static int bdi_sync_supers(void *);
 static void sync_supers_timer_fn(unsigned long);
 
-static void bdi_add_default_flusher_task(struct backing_dev_info *bdi);
+static void bdi_add_default_flusher_thread(struct backing_dev_info *bdi);
 
 #ifdef CONFIG_DEBUG_FS
 #include <linux/debugfs.h>
@@ -279,10 +279,10 @@ static void bdi_flush_io(struct backing_dev_info *bdi)
 }
 
 /*
- * kupdated() used to do this. We cannot do it from the bdi_forker_task()
+ * kupdated() used to do this. We cannot do it from the bdi_forker_thread()
  * or we risk deadlocking on ->s_umount. The longer term solution would be
  * to implement sync_supers_bdi() or similar and simply do it from the
- * bdi writeback tasks individually.
+ * bdi writeback thread individually.
  */
 static int bdi_sync_supers(void *unused)
 {
@@ -318,7 +318,7 @@ static void sync_supers_timer_fn(unsigned long unused)
         bdi_arm_supers_timer();
 }
 
-static int bdi_forker_task(void *ptr)
+static int bdi_forker_thread(void *ptr)
 {
         struct bdi_writeback *me = ptr;
 
@@ -354,7 +354,7 @@ static int bdi_forker_task(void *ptr)
                             !bdi_has_dirty_io(bdi))
                                 continue;
 
-                        bdi_add_default_flusher_task(bdi);
+                        bdi_add_default_flusher_thread(bdi);
                 }
 
                 set_current_state(TASK_INTERRUPTIBLE);
@@ -376,7 +376,7 @@ static int bdi_forker_task(void *ptr)
 
                 /*
                  * This is our real job - check for pending entries in
-                 * bdi_pending_list, and create the tasks that got added
+                 * bdi_pending_list, and create the threads that got added
                  */
                 bdi = list_entry(bdi_pending_list.next, struct backing_dev_info,
                                  bdi_list);
@@ -387,7 +387,7 @@ static int bdi_forker_task(void *ptr)
                 wb->task = kthread_run(bdi_writeback_thread, wb, "flush-%s",
                                         dev_name(bdi->dev));
                 /*
-                 * If task creation fails, then readd the bdi to
+                 * If thread creation fails, then readd the bdi to
                  * the pending list and force writeout of the bdi
                  * from this forker thread. That will free some memory
                  * and we can try again.
@@ -430,10 +430,10 @@ static void bdi_add_to_pending(struct rcu_head *head)
 }
 
 /*
- * Add the default flusher task that gets created for any bdi
+ * Add the default flusher thread that gets created for any bdi
  * that has dirty data pending writeout
  */
-void static bdi_add_default_flusher_task(struct backing_dev_info *bdi)
+static void bdi_add_default_flusher_thread(struct backing_dev_info *bdi)
 {
         if (!bdi_cap_writeback_dirty(bdi))
                 return;
@@ -445,10 +445,10 @@ void static bdi_add_default_flusher_task(struct backing_dev_info *bdi)
         }
 
         /*
-         * Check with the helper whether to proceed adding a task. Will only
+         * Check with the helper whether to proceed adding a thread. Will only
          * abort if we two or more simultanous calls to
-         * bdi_add_default_flusher_task() occured, further additions will block
-         * waiting for previous additions to finish.
+         * bdi_add_default_flusher_thread() occured, further additions will
+         * block waiting for previous additions to finish.
          */
         if (!test_and_set_bit(BDI_pending, &bdi->state)) {
                 list_del_rcu(&bdi->bdi_list);
@@ -506,7 +506,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
         if (bdi_cap_flush_forker(bdi)) {
                 struct bdi_writeback *wb = &bdi->wb;
 
-                wb->task = kthread_run(bdi_forker_task, wb, "bdi-%s",
+                wb->task = kthread_run(bdi_forker_thread, wb, "bdi-%s",
                                                 dev_name(dev));
                 if (IS_ERR(wb->task)) {
                         wb->task = NULL;