[PATCH 03/17] blktrans: track open and close calls.

From: Maxim Levitsky
Date: Sat Jan 30 2010 - 10:06:55 EST


This patch adds tracking for open and close calls.
Now trans ->open and ->release are never called twise in a row
->release is also called once before mtd device disappers

Proper locking will be added in follow up patch

Signed-off-by: Maxim Levitsky <maximlevitsky@xxxxxxxxx>
---
drivers/mtd/mtd_blkdevs.c | 18 ++++++++++++++++++
include/linux/mtd/blktrans.h | 1 +
2 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 93c87af..966398b 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -128,6 +128,9 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode)
if (!get_mtd_device(NULL, dev->mtd->index))
goto out;

+ if (dev->open++)
+ goto out;
+
if (!try_module_get(tr->owner))
goto out_tr;

@@ -153,6 +156,10 @@ static int blktrans_release(struct gendisk *disk, fmode_t mode)
struct mtd_blktrans_ops *tr = dev->tr;
int ret = 0;

+ dev->open--;
+ if (dev->open)
+ return 0;
+
if (tr->release)
ret = tr->release(dev);

@@ -304,6 +311,7 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
if (new->readonly)
set_disk_ro(gd, 1);

+ new->open = 0;
add_disk(gd);

return 0;
@@ -333,6 +341,16 @@ int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
/* Stop the thread */
kthread_stop(old->thread);

+ if (old->open) {
+ if (old->tr->release)
+ old->tr->release(old);
+ put_mtd_device(old->mtd);
+ }
+
+ /* From now on, no calls into trans can be made */
+ /* Mtd device will be gone real soon now */
+ old->mtd = NULL;
+
blk_cleanup_queue(old->rq);
return 0;
}
diff --git a/include/linux/mtd/blktrans.h b/include/linux/mtd/blktrans.h
index a4b3928..507f7b2 100644
--- a/include/linux/mtd/blktrans.h
+++ b/include/linux/mtd/blktrans.h
@@ -24,6 +24,7 @@ struct mtd_blktrans_dev {
int devnum;
unsigned long size;
int readonly;
+ int open;
struct gendisk *disk;
struct task_struct *thread;
struct request_queue *rq;
--
1.6.3.3

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