mtd: mtd_blkdevs: Replace request handler kthread with a workqueue

By replacing a kthread with a workqueue, the code is now a bit clearer. There's also a slight reduction of code size (numbers apply for x86): Before: text data bss dec hex filename 3248 36 0 3284 cd4 drivers/mtd/mtd_blkdevs.o After: text data bss dec hex filename 3150 36 0 3186 c72 drivers/mtd/mtd_blkdevs.o Due to lack of real hardware, tests have been performed on an emulated environment with mtdswap and mtdblock over nandsim devices. Some real testing should be done, before merging this patch. Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

mtd: mtd_blkdevs: Replace request handler kthread with a workqueue
By replacing a kthread with a workqueue, the code is now a bit clearer. There's also a slight reduction of code size (numbers apply for x86): Before: text data bss dec hex filename 3248 36 0 3284 cd4 drivers/mtd/mtd_blkdevs.o After: text data bss dec hex filename 3150 36 0 3186 c72 drivers/mtd/mtd_blkdevs.o Due to lack of real hardware, tests have been performed on an emulated environment with mtdswap and mtdblock over nandsim devices. Some real testing should be done, before merging this patch. Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Ezequiel Garcia · Artem Bityutskiy
1 parent 9329c5eb5b
Showing 2 changed files with 18 additions and 33 deletions Side-by-side Diff
drivers/mtd/mtd_blkdevs.c
include/linux/mtd/blktrans.h
@@ -32,7 +32,6 @@
 #include <linux/hdreg.h>
 #include <linux/init.h>
 #include <linux/mutex.h>
-#include <linux/kthread.h>
 #include <asm/uaccess.h>
  
 #include "mtdcore.h"
  
  
@@ -121,16 +120,14 @@
  
 int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
 {
-	if (kthread_should_stop())
-		return 1;
-
 	return dev->bg_stop;
 }
 EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
  
-static int mtd_blktrans_thread(void *arg)
+static void mtd_blktrans_work(struct work_struct *work)
 {
-	struct mtd_blktrans_dev *dev = arg;
+	struct mtd_blktrans_dev *dev =
+		container_of(work, struct mtd_blktrans_dev, work);
 	struct mtd_blktrans_ops *tr = dev->tr;
 	struct request_queue *rq = dev->rq;
 	struct request *req = NULL;
@@ -138,7 +135,7 @@
  
 	spin_lock_irq(rq->queue_lock);
  
-	while (!kthread_should_stop()) {
+	while (1) {
 		int res;
  
 		dev->bg_stop = false;
@@ -156,15 +153,7 @@
 				background_done = !dev->bg_stop;
 				continue;
 			}
-			set_current_state(TASK_INTERRUPTIBLE);
-
-			if (kthread_should_stop())
-				set_current_state(TASK_RUNNING);
-
-			spin_unlock_irq(rq->queue_lock);
-			schedule();
-			spin_lock_irq(rq->queue_lock);
-			continue;
+			break;
 		}
  
 		spin_unlock_irq(rq->queue_lock);
@@ -185,8 +174,6 @@
 		__blk_end_request_all(req, -EIO);
  
 	spin_unlock_irq(rq->queue_lock);
-
-	return 0;
 }
  
 static void mtd_blktrans_request(struct request_queue *rq)
@@ -199,10 +186,8 @@
 	if (!dev)
 		while ((req = blk_fetch_request(rq)) != NULL)
 			__blk_end_request_all(req, -ENODEV);
-	else {
-		dev->bg_stop = true;
-		wake_up_process(dev->thread);
-	}
+	else
+		queue_work(dev->wq, &dev->work);
 }
  
 static int blktrans_open(struct block_device *bdev, fmode_t mode)
  
@@ -437,14 +422,13 @@
  
 	gd->queue = new->rq;
  
-	/* Create processing thread */
-	/* TODO: workqueue ? */
-	new->thread = kthread_run(mtd_blktrans_thread, new,
-			"%s%d", tr->name, new->mtd->index);
-	if (IS_ERR(new->thread)) {
-		ret = PTR_ERR(new->thread);
+	/* Create processing workqueue */
+	new->wq = alloc_workqueue("%s%d", 0, 0,
+				  tr->name, new->mtd->index);
+	if (!new->wq)
 		goto error4;
-	}
+	INIT_WORK(&new->work, mtd_blktrans_work);
+
 	gd->driverfs_dev = &new->mtd->dev;
  
 	if (new->readonly)
@@ -484,9 +468,8 @@
 	/* Stop new requests to arrive */
 	del_gendisk(old->disk);
  
-
-	/* Stop the thread */
-	kthread_stop(old->thread);
+	/* Stop workqueue. This will perform any pending request. */
+	destroy_workqueue(old->wq);
  
 	/* Kill current requests */
 	spin_lock_irqsave(&old->queue_lock, flags);
@@ -23,6 +23,7 @@
 #include <linux/mutex.h>
 #include <linux/kref.h>
 #include <linux/sysfs.h>
+#include <linux/workqueue.h>
  
 struct hd_geometry;
 struct mtd_info;
@@ -43,7 +44,8 @@
 	struct kref ref;
 	struct gendisk *disk;
 	struct attribute_group *disk_attributes;
-	struct task_struct *thread;
+	struct workqueue_struct *wq;
+	struct work_struct work;
 	struct request_queue *rq;
 	spinlock_t queue_lock;
 	void *priv;
...	...	@@ -32,7 +32,6 @@
32	32	#include <linux/hdreg.h>
33	33	#include <linux/init.h>
34	34	#include <linux/mutex.h>
35		-#include <linux/kthread.h>
36	35	#include <asm/uaccess.h>
37	36
38	37	#include "mtdcore.h"
39	38
40	39
...	...	@@ -121,16 +120,14 @@
121	120
122	121	int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
123	122	{
124		- if (kthread_should_stop())
125		- return 1;
126		-
127	123	return dev->bg_stop;
128	124	}
129	125	EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
130	126
131		-static int mtd_blktrans_thread(void *arg)
	127	+static void mtd_blktrans_work(struct work_struct *work)
132	128	{
133		- struct mtd_blktrans_dev *dev = arg;
	129	+ struct mtd_blktrans_dev *dev =
	130	+ container_of(work, struct mtd_blktrans_dev, work);
134	131	struct mtd_blktrans_ops *tr = dev->tr;
135	132	struct request_queue *rq = dev->rq;
136	133	struct request *req = NULL;
...	...	@@ -138,7 +135,7 @@
138	135
139	136	spin_lock_irq(rq->queue_lock);
140	137
141		- while (!kthread_should_stop()) {
	138	+ while (1) {
142	139	int res;
143	140
144	141	dev->bg_stop = false;
...	...	@@ -156,15 +153,7 @@
156	153	background_done = !dev->bg_stop;
157	154	continue;
158	155	}
159		- set_current_state(TASK_INTERRUPTIBLE);
160		-
161		- if (kthread_should_stop())
162		- set_current_state(TASK_RUNNING);
163		-
164		- spin_unlock_irq(rq->queue_lock);
165		- schedule();
166		- spin_lock_irq(rq->queue_lock);
167		- continue;
	156	+ break;
168	157	}
169	158
170	159	spin_unlock_irq(rq->queue_lock);
...	...	@@ -185,8 +174,6 @@
185	174	__blk_end_request_all(req, -EIO);
186	175
187	176	spin_unlock_irq(rq->queue_lock);
188		-
189		- return 0;
190	177	}
191	178
192	179	static void mtd_blktrans_request(struct request_queue *rq)
...	...	@@ -199,10 +186,8 @@
199	186	if (!dev)
200	187	while ((req = blk_fetch_request(rq)) != NULL)
201	188	__blk_end_request_all(req, -ENODEV);
202		- else {
203		- dev->bg_stop = true;
204		- wake_up_process(dev->thread);
205		- }
	189	+ else
	190	+ queue_work(dev->wq, &dev->work);
206	191	}
207	192
208	193	static int blktrans_open(struct block_device *bdev, fmode_t mode)
209	194
...	...	@@ -437,14 +422,13 @@
437	422
438	423	gd->queue = new->rq;
439	424
440		- /* Create processing thread */
441		- /* TODO: workqueue ? */
442		- new->thread = kthread_run(mtd_blktrans_thread, new,
443		- "%s%d", tr->name, new->mtd->index);
444		- if (IS_ERR(new->thread)) {
445		- ret = PTR_ERR(new->thread);
	425	+ /* Create processing workqueue */
	426	+ new->wq = alloc_workqueue("%s%d", 0, 0,
	427	+ tr->name, new->mtd->index);
	428	+ if (!new->wq)
446	429	goto error4;
447		- }
	430	+ INIT_WORK(&new->work, mtd_blktrans_work);
	431	+
448	432	gd->driverfs_dev = &new->mtd->dev;
449	433
450	434	if (new->readonly)
...	...	@@ -484,9 +468,8 @@
484	468	/* Stop new requests to arrive */
485	469	del_gendisk(old->disk);
486	470
487		-
488		- /* Stop the thread */
489		- kthread_stop(old->thread);
	471	+ /* Stop workqueue. This will perform any pending request. */
	472	+ destroy_workqueue(old->wq);
490	473
491	474	/* Kill current requests */
492	475	spin_lock_irqsave(&old->queue_lock, flags);
...	...	@@ -23,6 +23,7 @@
23	23	#include <linux/mutex.h>
24	24	#include <linux/kref.h>
25	25	#include <linux/sysfs.h>
	26	+#include <linux/workqueue.h>
26	27
27	28	struct hd_geometry;
28	29	struct mtd_info;
...	...	@@ -43,7 +44,8 @@
43	44	struct kref ref;
44	45	struct gendisk *disk;
45	46	struct attribute_group *disk_attributes;
46		- struct task_struct *thread;
	47	+ struct workqueue_struct *wq;
	48	+ struct work_struct work;
47	49	struct request_queue *rq;
48	50	spinlock_t queue_lock;
49	51	void *priv;