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@nokia.com>
Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 344ac1037ee711d79b1a0e58fe992e66723363e3..e0b5f644217145aa7428fc9499cf97fa2aec4d0d 100644 (file)
--- 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 26529ebd59ccf3872fddca921c141184915fcf62..66bec4bf2b0a516b9b1cc1ab06bd0dbe6363d054 100644 (file)
--- 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__ */