Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d676c117 authored by Matthias Kaehlcke's avatar Matthias Kaehlcke Committed by David Woodhouse
Browse files

mtd: mtdblock: introduce mtdblks_lock 



The mtdblks array and its content are prone to race conditions. Introduce
the mutex mtdblks_lock in order to solve this.

[Amended by Artem Bityutskiy]

Signed-off-by: default avatarMatthias Kaehlcke <matthias@kaehlcke.net>
Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 2bf961b7

drivers/mtd/mtdblock.c

+15 −1
Original line number Diff line number Diff line
@@ -29,6 +29,8 @@ static struct mtdblk_dev { 
	enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;

} *mtdblks[MAX_MTD_DEVICES];



static struct mutex mtdblks_lock;



/*

 * Cache stuff...

 *
@@ -270,15 +272,19 @@ static int mtdblock_open(struct mtd_blktrans_dev *mbd) 


	DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");



	mutex_lock(&mtdblks_lock);

	if (mtdblks[dev]) {

		mtdblks[dev]->count++;

		mutex_unlock(&mtdblks_lock);

		return 0;

	}



	/* OK, it's not open. Create cache info for it */

	mtdblk = kzalloc(sizeof(struct mtdblk_dev), GFP_KERNEL);

	if (!mtdblk)

	if (!mtdblk) {

		mutex_unlock(&mtdblks_lock);

		return -ENOMEM;

	}



	mtdblk->count = 1;

	mtdblk->mtd = mtd;
@@ -291,6 +297,7 @@ static int mtdblock_open(struct mtd_blktrans_dev *mbd) 
	}



	mtdblks[dev] = mtdblk;

	mutex_unlock(&mtdblks_lock);



	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
@@ -304,6 +311,8 @@ static int mtdblock_release(struct mtd_blktrans_dev *mbd) 


   	DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");



	mutex_lock(&mtdblks_lock);



	mutex_lock(&mtdblk->cache_mutex);

	write_cached_data(mtdblk);

	mutex_unlock(&mtdblk->cache_mutex);
@@ -316,6 +325,9 @@ static int mtdblock_release(struct mtd_blktrans_dev *mbd) 
		vfree(mtdblk->cache_data);

		kfree(mtdblk);

	}



	mutex_unlock(&mtdblks_lock);



	DEBUG(MTD_DEBUG_LEVEL1, "ok\n");



	return 0;
@@ -376,6 +388,8 @@ static struct mtd_blktrans_ops mtdblock_tr = { 


static int __init init_mtdblock(void)

{

	mutex_init(&mtdblks_lock);



	return register_mtd_blktrans(&mtdblock_tr);

}