mtd_blkdevs: Add background processing support

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=c7519dbf6f4b4408229d279d799c938ffdd06f21
Commit:     c7519dbf6f4b4408229d279d799c938ffdd06f21
Parent:     13ce77f46c79a3839e4c2ff9722c9416c165f498
Author:     Jarkko Lavinen <jarkko.lavinen at nokia.com>
AuthorDate: Mon Feb 14 16:16:09 2011 +0200
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Fri Mar 11 14:22:46 2011 +0000

    mtd_blkdevs: Add background processing support
    
    Add a new background method into mtd_blktrans_ops, add background support
    into mtd_blktrans_thread(), and add mtd_blktrans_cease_background().
    
    If the mtd blktrans dev has the background support, the thread will
    call background function when the request queue becomes empty. The background
    operation may run as long as needs to until
    mtd_blktrans_cease_background() tells to stop.
    
    Signed-off-by: Jarkko Lavinen <jarkko.lavinen at nokia.com>
    Tested-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
 drivers/mtd/mtd_blkdevs.c    |   26 ++++++++++++++++++++++++++
 include/linux/mtd/blktrans.h |    2 ++
 2 files changed, 28 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 344ac10..e0b5f64 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -119,11 +119,22 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr,
 	}
 }
 
+int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev)
+{
+	if (kthread_should_stop())
+		return 1;
+
+	return !elv_queue_empty(dev->rq);
+}
+EXPORT_SYMBOL_GPL(mtd_blktrans_cease_background);
+
 static int mtd_blktrans_thread(void *arg)
 {
 	struct mtd_blktrans_dev *dev = arg;
+	struct mtd_blktrans_ops *tr = dev->tr;
 	struct request_queue *rq = dev->rq;
 	struct request *req = NULL;
+	int background_done = 0;
 
 	spin_lock_irq(rq->queue_lock);
 
@@ -131,6 +142,19 @@ static int mtd_blktrans_thread(void *arg)
 		int res;
 
 		if (!req && !(req = blk_fetch_request(rq))) {
+			if (tr->background && !background_done) {
+				spin_unlock_irq(rq->queue_lock);
+				mutex_lock(&dev->lock);
+				tr->background(dev);
+				mutex_unlock(&dev->lock);
+				spin_lock_irq(rq->queue_lock);
+				/*
+				 * Do background processing just once per idle
+				 * period.
+				 */
+				background_done = 1;
+				continue;
+			}
 			set_current_state(TASK_INTERRUPTIBLE);
 
 			if (kthread_should_stop())
@@ -152,6 +176,8 @@ static int mtd_blktrans_thread(void *arg)
 
 		if (!__blk_end_request_cur(req, res))
 			req = NULL;
+
+		background_done = 0;
 	}
 
 	if (req)
diff --git a/include/linux/mtd/blktrans.h b/include/linux/mtd/blktrans.h
index 26529eb..66bec4b 100644
--- a/include/linux/mtd/blktrans.h
+++ b/include/linux/mtd/blktrans.h
@@ -62,6 +62,7 @@ struct mtd_blktrans_ops {
 		     unsigned long block, char *buffer);
 	int (*discard)(struct mtd_blktrans_dev *dev,
 		       unsigned long block, unsigned nr_blocks);
+	void (*background)(struct mtd_blktrans_dev *dev);
 
 	/* Block layer ioctls */
 	int (*getgeo)(struct mtd_blktrans_dev *dev, struct hd_geometry *geo);
@@ -85,6 +86,7 @@ extern int register_mtd_blktrans(struct mtd_blktrans_ops *tr);
 extern int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr);
 extern int add_mtd_blktrans_dev(struct mtd_blktrans_dev *dev);
 extern int del_mtd_blktrans_dev(struct mtd_blktrans_dev *dev);
+extern int mtd_blktrans_cease_background(struct mtd_blktrans_dev *dev);
 
 
 #endif /* __MTD_TRANS_H__ */