Patchwork [3/4] MTD: blkdevs: make hotplug work

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Submitter Maxim Levitsky
Date Jan. 22, 2010, 3:35 p.m.
Message ID <1264174506.24012.21.camel@maxim-laptop>
Download mbox | patch
Permalink /patch/43486/
State New, archived
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Comments

Maxim Levitsky - Jan. 22, 2010, 3:35 p.m.
>From 368127067f4d39ba89096e4a5cb3be2dee361bad Mon Sep 17 00:00:00 2001
From: Maxim Levitsky <maximlevitsky@gmail.com>
Date: Fri, 22 Jan 2010 15:00:55 +0200
Subject: [PATCH 3/4] MTD: blkdevs: make hotplug work

This changes the blkdev common module for translation layers
to survive when underlying mtd device disappears.

To do so the following conceptual changes were made:

* disk queue and thread are now one per mtd device
 This was it is easy to flush and destroy the queue

* the struct mtd_blktrans_dev will now be freed automaticly when last user
 of the device quits.
 All existing translation layers are adjusted

* ->open and release function of the translation layer will never be called
 twise or more in the row.
 This makes code simplier.
 Also the ->release will be called just before mtd device disappears
 This and above is the only visable changes on the outside.

Tested with mtdblock, ssfdc and my own sm_ftl on top of physicly hotplugable
nand card.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
---
 drivers/mtd/ftl.c            |    1 -
 drivers/mtd/inftlcore.c      |    1 -
 drivers/mtd/mtd_blkdevs.c    |  237 ++++++++++++++++++++++++++---------------
 drivers/mtd/mtdblock.c       |    1 -
 drivers/mtd/mtdblock_ro.c    |    1 -
 drivers/mtd/mtdcore.c        |    3 +-
 drivers/mtd/nftlcore.c       |    1 -
 drivers/mtd/rfd_ftl.c        |    1 -
 drivers/mtd/ssfdc.c          |    1 -
 include/linux/mtd/blktrans.h |   13 ++-
 10 files changed, 160 insertions(+), 100 deletions(-)
Artem Bityutskiy - Jan. 22, 2010, 3:59 p.m.
On Fri, 2010-01-22 at 17:35 +0200, Maxim Levitsky wrote:
> >From 368127067f4d39ba89096e4a5cb3be2dee361bad Mon Sep 17 00:00:00 2001
> From: Maxim Levitsky <maximlevitsky@gmail.com>
> Date: Fri, 22 Jan 2010 15:00:55 +0200
> Subject: [PATCH 3/4] MTD: blkdevs: make hotplug work
> 
> This changes the blkdev common module for translation layers
> to survive when underlying mtd device disappears.
> 
> To do so the following conceptual changes were made:
> 
> * disk queue and thread are now one per mtd device
>  This was it is easy to flush and destroy the queue
> 
> * the struct mtd_blktrans_dev will now be freed automaticly when last user
>  of the device quits.
>  All existing translation layers are adjusted
> 
> * ->open and release function of the translation layer will never be called
>  twise or more in the row.
>  This makes code simplier.
>  Also the ->release will be called just before mtd device disappears
>  This and above is the only visable changes on the outside.
> 
> Tested with mtdblock, ssfdc and my own sm_ftl on top of physicly hotplugable
> nand card.
> 
> Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>

I'll try to find some time to review this later - I'm really busy
lately. But please, split this huge patch on smaller pieces - this will
help the reviewers a lot.
Maxim Levitsky - Jan. 22, 2010, 9:51 p.m.
On Fri, 2010-01-22 at 17:59 +0200, Artem Bityutskiy wrote: 
> On Fri, 2010-01-22 at 17:35 +0200, Maxim Levitsky wrote:
> > >From 368127067f4d39ba89096e4a5cb3be2dee361bad Mon Sep 17 00:00:00 2001
> > From: Maxim Levitsky <maximlevitsky@gmail.com>
> > Date: Fri, 22 Jan 2010 15:00:55 +0200
> > Subject: [PATCH 3/4] MTD: blkdevs: make hotplug work
> > 
> > This changes the blkdev common module for translation layers
> > to survive when underlying mtd device disappears.
> > 
> > To do so the following conceptual changes were made:
> > 
> > * disk queue and thread are now one per mtd device
> >  This was it is easy to flush and destroy the queue
> > 
> > * the struct mtd_blktrans_dev will now be freed automaticly when last user
> >  of the device quits.
> >  All existing translation layers are adjusted
> > 
> > * ->open and release function of the translation layer will never be called
> >  twise or more in the row.
> >  This makes code simplier.
> >  Also the ->release will be called just before mtd device disappears
> >  This and above is the only visable changes on the outside.
> > 
> > Tested with mtdblock, ssfdc and my own sm_ftl on top of physicly hotplugable
> > nand card.
> > 
> > Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
> 
> I'll try to find some time to review this later - I'm really busy
> lately. But please, split this huge patch on smaller pieces - this will
> help the reviewers a lot.
> 
Sure, but I afraid this won't be easy. To split the patch I will need
effectively to redo all the work from the beginning.
Isn't it possible just to review the mtd_blkdevs.c and blktrans.h as
if it was new driver?

This patch does touch all ftl drivers, but only removes the final free
of structure that holds or embeds the 'struct mtd_blktrans_dev'

Change in drivers/mtd/mtdcore.c is my mistake, this slipped from
previous patch, sorry.

Do you think its real to merge my work into 2.6.34 ?
What else should I do besides splitting this patch?

Best regards,
Maxim Levitsky

Patch

diff --git a/drivers/mtd/ftl.c b/drivers/mtd/ftl.c
index e56d6b4..62da9eb 100644
--- a/drivers/mtd/ftl.c
+++ b/drivers/mtd/ftl.c
@@ -1082,7 +1082,6 @@  static void ftl_remove_dev(struct mtd_blktrans_dev *dev)
 {
 	del_mtd_blktrans_dev(dev);
 	ftl_freepart((partition_t *)dev);
-	kfree(dev);
 }
 
 static struct mtd_blktrans_ops ftl_tr = {
diff --git a/drivers/mtd/inftlcore.c b/drivers/mtd/inftlcore.c
index 8aca552..015a7fe 100755
--- a/drivers/mtd/inftlcore.c
+++ b/drivers/mtd/inftlcore.c
@@ -139,7 +139,6 @@  static void inftl_remove_dev(struct mtd_blktrans_dev *dev)
 
 	kfree(inftl->PUtable);
 	kfree(inftl->VUtable);
-	kfree(inftl);
 }
 
 /*
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index c82e09b..04a875f 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -26,11 +26,6 @@ 
 
 static LIST_HEAD(blktrans_majors);
 
-struct mtd_blkcore_priv {
-	struct task_struct *thread;
-	struct request_queue *rq;
-	spinlock_t queue_lock;
-};
 
 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
 			       struct mtd_blktrans_dev *dev,
@@ -80,14 +75,13 @@  static int do_blktrans_request(struct mtd_blktrans_ops *tr,
 
 static int mtd_blktrans_thread(void *arg)
 {
-	struct mtd_blktrans_ops *tr = arg;
-	struct request_queue *rq = tr->blkcore_priv->rq;
+	struct mtd_blktrans_dev *dev = arg;
+	struct request_queue *rq = dev->rq;
 	struct request *req = NULL;
 
 	spin_lock_irq(rq->queue_lock);
 
 	while (!kthread_should_stop()) {
-		struct mtd_blktrans_dev *dev;
 		int res;
 
 		if (!req && !(req = blk_fetch_request(rq))) {
@@ -98,13 +92,10 @@  static int mtd_blktrans_thread(void *arg)
 			continue;
 		}
 
-		dev = req->rq_disk->private_data;
-		tr = dev->tr;
-
 		spin_unlock_irq(rq->queue_lock);
 
 		mutex_lock(&dev->lock);
-		res = do_blktrans_request(tr, dev, req);
+		res = do_blktrans_request(dev->tr, dev, req);
 		mutex_unlock(&dev->lock);
 
 		spin_lock_irq(rq->queue_lock);
@@ -123,8 +114,14 @@  static int mtd_blktrans_thread(void *arg)
 
 static void mtd_blktrans_request(struct request_queue *rq)
 {
-	struct mtd_blktrans_ops *tr = rq->queuedata;
-	wake_up_process(tr->blkcore_priv->thread);
+	struct mtd_blktrans_dev *dev = rq->queuedata;
+	struct request *req = NULL;
+
+	if (dev->deleted)
+		while ((req = blk_fetch_request(rq)) != NULL)
+			__blk_end_request_all(req, -ENODEV);
+	else
+		wake_up_process(dev->thread);
 }
 

@@ -132,72 +129,108 @@  static int blktrans_open(struct block_device *bdev, fmode_t mode)
 {
 	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
 	struct mtd_blktrans_ops *tr = dev->tr;
-	int ret = -ENODEV;
+	int ret = 0;
+
+	mutex_lock(&dev->lock);
+	if (dev->open++)
+		goto out;
 
-	if (!get_mtd_device(NULL, dev->mtd->index))
+	if (dev->deleted)
 		goto out;
 
+	ret = -ENODEV;
 	if (!try_module_get(tr->owner))
-		goto out_tr;
+		goto out;
 
-	/* FIXME: Locking. A hot pluggable device can go away
-	   (del_mtd_device can be called for it) without its module
-	   being unloaded. */
-	dev->mtd->usecount++;
+	if (__get_mtd_device(dev->mtd)) {
+		module_put(tr->owner);
+		goto out;
+	}
 
 	ret = 0;
 	if (tr->open && (ret = tr->open(dev))) {
-		dev->mtd->usecount--;
-		put_mtd_device(dev->mtd);
-	out_tr:
 		module_put(tr->owner);
+		__put_mtd_device(dev->mtd);
+		goto out;
 	}
  out:
+	mutex_unlock(&dev->lock);
 	return ret;
 }
 
+
 static int blktrans_release(struct gendisk *disk, fmode_t mode)
 {
 	struct mtd_blktrans_dev *dev = disk->private_data;
 	struct mtd_blktrans_ops *tr = dev->tr;
 	int ret = 0;
 
-	if (tr->release)
-		ret = tr->release(dev);
+	mutex_lock(&dev->lock);
+	dev->open--;
+	if (dev->open)
+		goto out;
 
-	if (!ret) {
-		dev->mtd->usecount--;
-		put_mtd_device(dev->mtd);
+	/* Free the private data */
+	if (dev->deleted) {
 		module_put(tr->owner);
+		mutex_unlock(&dev->lock);
+		kfree(dev);
+		return 0;
 	}
 
+	ret = tr->release ? tr->release(dev) : 0;
+	module_put(tr->owner);
+
+	if (dev->mtd)
+		__put_mtd_device(dev->mtd);
+out:
+	mutex_unlock(&dev->lock);
 	return ret;
 }
 
 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 {
 	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
+	int error;
+
+	mutex_lock(&dev->lock);
 
+	error = -ENODEV;
+	if (dev->deleted)
+		goto out;
+
+	error = -ENOTTY;
 	if (dev->tr->getgeo)
-		return dev->tr->getgeo(dev, geo);
-	return -ENOTTY;
+		error = dev->tr->getgeo(dev, geo);
+out:
+	mutex_unlock(&dev->lock);
+	return error;
 }
 
 static int blktrans_ioctl(struct block_device *bdev, fmode_t mode,
 			      unsigned int cmd, unsigned long arg)
 {
 	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
-	struct mtd_blktrans_ops *tr = dev->tr;
+	int error = -ENODEV;
+
+	mutex_lock(&dev->lock);
+
+	if (dev->deleted)
+		goto out;
+
+	error = -ENOTTY;
 
 	switch (cmd) {
 	case BLKFLSBUF:
-		if (tr->flush)
-			return tr->flush(dev);
-		/* The core code did the work, we had nothing to do. */
-		return 0;
+		if (dev->tr->flush)
+			error = dev->tr->flush(dev);
+		break;
 	default:
-		return -ENOTTY;
+		break;
 	}
+out:
+	mutex_unlock(&dev->lock);
+	return error;
 }
 
 static const struct block_device_operations mtd_blktrans_ops = {
@@ -214,6 +247,7 @@  int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 	struct mtd_blktrans_dev *d;
 	int last_devnum = -1;
 	struct gendisk *gd;
+	int ret;
 
 	if (mutex_trylock(&mtd_table_mutex)) {
 		mutex_unlock(&mtd_table_mutex);
@@ -239,12 +273,13 @@  int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 		}
 		last_devnum = d->devnum;
 	}
+
+	ret = -EBUSY;
 	if (new->devnum == -1)
 		new->devnum = last_devnum+1;
 
-	if ((new->devnum << tr->part_bits) > 256) {
-		return -EBUSY;
-	}
+	if ((new->devnum << tr->part_bits) > 256)
+		goto error1;
 
 	list_add_tail(&new->list, &tr->devs);
  added:
@@ -252,11 +287,16 @@  int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 	if (!tr->writesect)
 		new->readonly = 1;
 
+
+	/* Create gendisk */
+	ret = -ENOMEM;
 	gd = alloc_disk(1 << tr->part_bits);
-	if (!gd) {
-		list_del(&new->list);
-		return -ENOMEM;
-	}
+
+	if (!gd)
+		goto error2;
+
+	new->disk = gd;
+	gd->private_data = new;
 	gd->major = tr->major;
 	gd->first_minor = (new->devnum) << tr->part_bits;
 	gd->fops = &mtd_blktrans_ops;
@@ -274,25 +314,58 @@  int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 		snprintf(gd->disk_name, sizeof(gd->disk_name),
 			 "%s%d", tr->name, new->devnum);
 
-	/* 2.5 has capacity in units of 512 bytes while still
-	   having BLOCK_SIZE_BITS set to 10. Just to keep us amused. */
 	set_capacity(gd, (new->size * tr->blksize) >> 9);
 
-	gd->private_data = new;
-	new->blkcore_priv = gd;
-	gd->queue = tr->blkcore_priv->rq;
+
+	/* Create the request queue */
+	spin_lock_init(&new->queue_lock);
+	new->rq = blk_init_queue(mtd_blktrans_request, &new->queue_lock);
+
+	if (!new->rq)
+		goto error3;
+
+	new->rq->queuedata = new;
+	blk_queue_logical_block_size(new->rq, tr->blksize);
+
+	if (tr->discard)
+		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
+					new->rq);
+
+	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);
+		goto error4;
+	}
+
 	gd->driverfs_dev = &new->mtd->dev;
 
 	if (new->readonly)
 		set_disk_ro(gd, 1);
 
+	new->open = 0;
 	add_disk(gd);
 
 	return 0;
+error4:
+	blk_cleanup_queue(new->rq);
+error3:
+	put_disk(new->disk);
+error2:
+	list_del(&new->list);
+error1:
+	kfree(new);
+	return ret;
 }
 
 int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
 {
+	unsigned long flags;
+
 	if (mutex_trylock(&mtd_table_mutex)) {
 		mutex_unlock(&mtd_table_mutex);
 		BUG();
@@ -300,9 +373,35 @@  int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
 
 	list_del(&old->list);
 
-	del_gendisk(old->blkcore_priv);
-	put_disk(old->blkcore_priv);
+	/* stop new requests to arrive */
+	del_gendisk(old->disk);
+
+
+	/* flush current requests */
+	spin_lock_irqsave(&old->queue_lock, flags);
+	old->deleted = 1;
+	blk_start_queue(old->rq);
+	spin_unlock_irqrestore(&old->queue_lock, flags);
+
+
+	/* Stop the thread */
+	kthread_stop(old->thread);
 
+	/* Tell trans driver to release the device */
+	mutex_lock(&old->lock);
+
+	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;
+	mutex_unlock(&old->lock);
+
+	blk_cleanup_queue(old->rq);
 	return 0;
 }
 
@@ -343,9 +442,6 @@  int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
 	if (!blktrans_notifier.list.next)
 		register_mtd_user(&blktrans_notifier);
 
-	tr->blkcore_priv = kzalloc(sizeof(*tr->blkcore_priv), GFP_KERNEL);
-	if (!tr->blkcore_priv)
-		return -ENOMEM;
 
 	mutex_lock(&mtd_table_mutex);
 
@@ -353,39 +449,12 @@  int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
 	if (ret) {
 		printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
 		       tr->name, tr->major, ret);
-		kfree(tr->blkcore_priv);
 		mutex_unlock(&mtd_table_mutex);
 		return ret;
 	}
-	spin_lock_init(&tr->blkcore_priv->queue_lock);
-
-	tr->blkcore_priv->rq = blk_init_queue(mtd_blktrans_request, &tr->blkcore_priv->queue_lock);
-	if (!tr->blkcore_priv->rq) {
-		unregister_blkdev(tr->major, tr->name);
-		kfree(tr->blkcore_priv);
-		mutex_unlock(&mtd_table_mutex);
-		return -ENOMEM;
-	}
-
-	tr->blkcore_priv->rq->queuedata = tr;
-	blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize);
-	if (tr->discard)
-		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
-					tr->blkcore_priv->rq);
 
 	tr->blkshift = ffs(tr->blksize) - 1;
 
-	tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
-			"%sd", tr->name);
-	if (IS_ERR(tr->blkcore_priv->thread)) {
-		ret = PTR_ERR(tr->blkcore_priv->thread);
-		blk_cleanup_queue(tr->blkcore_priv->rq);
-		unregister_blkdev(tr->major, tr->name);
-		kfree(tr->blkcore_priv);
-		mutex_unlock(&mtd_table_mutex);
-		return ret;
-	}
-
 	INIT_LIST_HEAD(&tr->devs);
 	list_add(&tr->list, &blktrans_majors);
 
@@ -405,8 +474,6 @@  int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
 
 	mutex_lock(&mtd_table_mutex);
 
-	/* Clean up the kernel thread */
-	kthread_stop(tr->blkcore_priv->thread);
 
 	/* Remove it from the list of active majors */
 	list_del(&tr->list);
@@ -414,13 +481,9 @@  int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
 	list_for_each_entry_safe(dev, next, &tr->devs, list)
 		tr->remove_dev(dev);
 
-	blk_cleanup_queue(tr->blkcore_priv->rq);
 	unregister_blkdev(tr->major, tr->name);
-
 	mutex_unlock(&mtd_table_mutex);
 
-	kfree(tr->blkcore_priv);
-
 	BUG_ON(!list_empty(&tr->devs));
 	return 0;
 }
diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
index 9f41b1a..d8322cc 100644
--- a/drivers/mtd/mtdblock.c
+++ b/drivers/mtd/mtdblock.c
@@ -368,7 +368,6 @@  static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
 {
 	del_mtd_blktrans_dev(dev);
-	kfree(dev);
 }
 
 static struct mtd_blktrans_ops mtdblock_tr = {
diff --git a/drivers/mtd/mtdblock_ro.c b/drivers/mtd/mtdblock_ro.c
index 852165f..54ff288 100644
--- a/drivers/mtd/mtdblock_ro.c
+++ b/drivers/mtd/mtdblock_ro.c
@@ -49,7 +49,6 @@  static void mtdblock_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 static void mtdblock_remove_dev(struct mtd_blktrans_dev *dev)
 {
 	del_mtd_blktrans_dev(dev);
-	kfree(dev);
 }
 
 static struct mtd_blktrans_ops mtdblock_tr = {
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 96b4a05..0e86208 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -540,7 +540,6 @@  void put_mtd_device(struct mtd_info *mtd)
 	__put_mtd_device(mtd);
 	mutex_unlock(&mtd_table_mutex);
 
-	module_put(mtd->owner);
 }
 
 void __put_mtd_device(struct mtd_info *mtd)
@@ -550,6 +549,8 @@  void __put_mtd_device(struct mtd_info *mtd)
 
 	if (mtd->put_device)
 		mtd->put_device(mtd);
+
+	module_put(mtd->owner);
 }
 
 /* default_mtd_writev - default mtd writev method for MTD devices that
diff --git a/drivers/mtd/nftlcore.c b/drivers/mtd/nftlcore.c
index 1002e18..a4578bf 100644
--- a/drivers/mtd/nftlcore.c
+++ b/drivers/mtd/nftlcore.c
@@ -126,7 +126,6 @@  static void nftl_remove_dev(struct mtd_blktrans_dev *dev)
 	del_mtd_blktrans_dev(dev);
 	kfree(nftl->ReplUnitTable);
 	kfree(nftl->EUNtable);
-	kfree(nftl);
 }
 
 /*
diff --git a/drivers/mtd/rfd_ftl.c b/drivers/mtd/rfd_ftl.c
index d2aa9c4..63b83c0 100644
--- a/drivers/mtd/rfd_ftl.c
+++ b/drivers/mtd/rfd_ftl.c
@@ -817,7 +817,6 @@  static void rfd_ftl_remove_dev(struct mtd_blktrans_dev *dev)
 	vfree(part->sector_map);
 	kfree(part->header_cache);
 	kfree(part->blocks);
-	kfree(part);
 }
 
 static struct mtd_blktrans_ops rfd_ftl_tr = {
diff --git a/drivers/mtd/ssfdc.c b/drivers/mtd/ssfdc.c
index 3f67e00..81c4ecd 100644
--- a/drivers/mtd/ssfdc.c
+++ b/drivers/mtd/ssfdc.c
@@ -375,7 +375,6 @@  static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev)
 
 	del_mtd_blktrans_dev(dev);
 	kfree(ssfdc->logic_block_map);
-	kfree(ssfdc);
 }
 
 static int ssfdcr_readsect(struct mtd_blktrans_dev *dev,
diff --git a/include/linux/mtd/blktrans.h b/include/linux/mtd/blktrans.h
index 8b4aa05..054b053 100644
--- a/include/linux/mtd/blktrans.h
+++ b/include/linux/mtd/blktrans.h
@@ -24,10 +24,15 @@  struct mtd_blktrans_dev {
 	int devnum;
 	unsigned long size;
 	int readonly;
-	void *blkcore_priv; /* gendisk in 2.5, devfs_handle in 2.4 */
-};
+	int deleted;
+	int open;
 
-struct blkcore_priv; /* Differs for 2.4 and 2.5 kernels; private */
+	struct gendisk *disk;
+	struct task_struct *thread;
+	struct request_queue *rq;
+	spinlock_t queue_lock;
+	void *priv;
+};
 
 struct mtd_blktrans_ops {
 	char *name;
@@ -60,8 +65,6 @@  struct mtd_blktrans_ops {
 	struct list_head devs;
 	struct list_head list;
 	struct module *owner;
-
-	struct mtd_blkcore_priv *blkcore_priv;
 };
 
 extern int register_mtd_blktrans(struct mtd_blktrans_ops *tr);