writeback: simplify and split bdi_start_writeback

bdi_start_writeback now never gets a superblock passed, so we can just remove that case. And to further untangle the code and flatten the call stack split it into two trivial helpers for it's two callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

writeback: simplify and split bdi_start_writeback
bdi_start_writeback now never gets a superblock passed, so we can just remove that case. And to further untangle the code and flatten the call stack split it into two trivial helpers for it's two callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Christoph Hellwig · Jens Axboe
1 parent b8c2f3474f
Showing 3 changed files with 24 additions and 17 deletions Side-by-side Diff
fs/fs-writeback.c
include/linux/backing-dev.h
mm/page-writeback.c
@@ -200,7 +200,6 @@
 /**
  * bdi_start_writeback - start writeback
  * @bdi: the backing device to write from
- * @sb: write inodes from this super_block
  * @nr_pages: the number of pages to write
  *
  * Description:
  
  
  
@@ -209,25 +208,34 @@
  *   completion. Caller need not hold sb s_umount semaphore.
  *
  */
-void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb,
-			 long nr_pages)
+void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
 {
 	struct wb_writeback_args args = {
-		.sb		= sb,
 		.sync_mode	= WB_SYNC_NONE,
 		.nr_pages	= nr_pages,
 		.range_cyclic	= 1,
 	};
  
-	/*
-	 * We treat @nr_pages=0 as the special case to do background writeback,
-	 * ie. to sync pages until the background dirty threshold is reached.
-	 */
-	if (!nr_pages) {
-		args.nr_pages = LONG_MAX;
-		args.for_background = 1;
-	}
+	bdi_alloc_queue_work(bdi, &args);
+}
  
+/**
+ * bdi_start_background_writeback - start background writeback
+ * @bdi: the backing device to write from
+ *
+ * Description:
+ *   This does WB_SYNC_NONE background writeback. The IO is only
+ *   started when this function returns, we make no guarentees on
+ *   completion. Caller need not hold sb s_umount semaphore.
+ */
+void bdi_start_background_writeback(struct backing_dev_info *bdi)
+{
+	struct wb_writeback_args args = {
+		.sync_mode	= WB_SYNC_NONE,
+		.nr_pages	= LONG_MAX,
+		.for_background = 1,
+		.range_cyclic	= 1,
+	};
 	bdi_alloc_queue_work(bdi, &args);
 }
  
@@ -105,8 +105,8 @@
 int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
 void bdi_unregister(struct backing_dev_info *bdi);
 int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int);
-void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb,
-				long nr_pages);
+void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
+void bdi_start_background_writeback(struct backing_dev_info *bdi);
 int bdi_writeback_task(struct bdi_writeback *wb);
 int bdi_has_dirty_io(struct backing_dev_info *bdi);
 void bdi_arm_supers_timer(void);
@@ -597,7 +597,7 @@
 	    (!laptop_mode && ((global_page_state(NR_FILE_DIRTY)
 			       + global_page_state(NR_UNSTABLE_NFS))
 					  > background_thresh)))
-		bdi_start_writeback(bdi, NULL, 0);
+		bdi_start_background_writeback(bdi);
 }
  
 void set_page_dirty_balance(struct page *page, int page_mkwrite)
  
@@ -705,9 +705,8 @@
 	 * We want to write everything out, not just down to the dirty
 	 * threshold
 	 */
-
 	if (bdi_has_dirty_io(&q->backing_dev_info))
-		bdi_start_writeback(&q->backing_dev_info, NULL, nr_pages);
+		bdi_start_writeback(&q->backing_dev_info, nr_pages);
 }
  
 /*
...	...	@@ -200,7 +200,6 @@
200	200	/**
201	201	* bdi_start_writeback - start writeback
202	202	* @bdi: the backing device to write from
203		- * @sb: write inodes from this super_block
204	203	* @nr_pages: the number of pages to write
205	204	*
206	205	* Description:
207	206
208	207
209	208
...	...	@@ -209,25 +208,34 @@
209	208	* completion. Caller need not hold sb s_umount semaphore.
210	209	*
211	210	*/
212		-void bdi_start_writeback(struct backing_dev_info bdi, struct super_block sb,
213		- long nr_pages)
	211	+void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages)
214	212	{
215	213	struct wb_writeback_args args = {
216		- .sb = sb,
217	214	.sync_mode = WB_SYNC_NONE,
218	215	.nr_pages = nr_pages,
219	216	.range_cyclic = 1,
220	217	};
221	218
222		- /*
223		- * We treat @nr_pages=0 as the special case to do background writeback,
224		- * ie. to sync pages until the background dirty threshold is reached.
225		- */
226		- if (!nr_pages) {
227		- args.nr_pages = LONG_MAX;
228		- args.for_background = 1;
229		- }
	219	+ bdi_alloc_queue_work(bdi, &args);
	220	+}
230	221
	222	+/**
	223	+ * bdi_start_background_writeback - start background writeback
	224	+ * @bdi: the backing device to write from
	225	+ *
	226	+ * Description:
	227	+ * This does WB_SYNC_NONE background writeback. The IO is only
	228	+ * started when this function returns, we make no guarentees on
	229	+ * completion. Caller need not hold sb s_umount semaphore.
	230	+ */
	231	+void bdi_start_background_writeback(struct backing_dev_info *bdi)
	232	+{
	233	+ struct wb_writeback_args args = {
	234	+ .sync_mode = WB_SYNC_NONE,
	235	+ .nr_pages = LONG_MAX,
	236	+ .for_background = 1,
	237	+ .range_cyclic = 1,
	238	+ };
231	239	bdi_alloc_queue_work(bdi, &args);
232	240	}
233	241
...	...	@@ -105,8 +105,8 @@
105	105	int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
106	106	void bdi_unregister(struct backing_dev_info *bdi);
107	107	int bdi_setup_and_register(struct backing_dev_info , char , unsigned int);
108		-void bdi_start_writeback(struct backing_dev_info bdi, struct super_block sb,
109		- long nr_pages);
	108	+void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages);
	109	+void bdi_start_background_writeback(struct backing_dev_info *bdi);
110	110	int bdi_writeback_task(struct bdi_writeback *wb);
111	111	int bdi_has_dirty_io(struct backing_dev_info *bdi);
112	112	void bdi_arm_supers_timer(void);
...	...	@@ -597,7 +597,7 @@
597	597	(!laptop_mode && ((global_page_state(NR_FILE_DIRTY)
598	598	+ global_page_state(NR_UNSTABLE_NFS))
599	599	> background_thresh)))
600		- bdi_start_writeback(bdi, NULL, 0);
	600	+ bdi_start_background_writeback(bdi);
601	601	}
602	602
603	603	void set_page_dirty_balance(struct page *page, int page_mkwrite)
604	604
...	...	@@ -705,9 +705,8 @@
705	705	* We want to write everything out, not just down to the dirty
706	706	* threshold
707	707	*/
708		-
709	708	if (bdi_has_dirty_io(&q->backing_dev_info))
710		- bdi_start_writeback(&q->backing_dev_info, NULL, nr_pages);
	709	+ bdi_start_writeback(&q->backing_dev_info, nr_pages);
711	710	}
712	711
713	712	/*