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: Matthias Kaehlcke <matthias@kaehlcke.net> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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@ -29,6 +29,8 @@ static struct mtdblk_dev {
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enum { STATE_EMPTY, STATE_CLEAN, STATE_DIRTY } cache_state;
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} *mtdblks[MAX_MTD_DEVICES];
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static struct mutex mtdblks_lock;
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/*
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* Cache stuff...
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*
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@ -270,15 +272,19 @@ static int mtdblock_open(struct mtd_blktrans_dev *mbd)
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DEBUG(MTD_DEBUG_LEVEL1,"mtdblock_open\n");
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mutex_lock(&mtdblks_lock);
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if (mtdblks[dev]) {
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mtdblks[dev]->count++;
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mutex_unlock(&mtdblks_lock);
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return 0;
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}
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/* OK, it's not open. Create cache info for it */
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mtdblk = kzalloc(sizeof(struct mtdblk_dev), GFP_KERNEL);
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if (!mtdblk)
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if (!mtdblk) {
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mutex_unlock(&mtdblks_lock);
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return -ENOMEM;
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}
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mtdblk->count = 1;
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mtdblk->mtd = mtd;
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@ -291,6 +297,7 @@ static int mtdblock_open(struct mtd_blktrans_dev *mbd)
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}
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mtdblks[dev] = mtdblk;
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mutex_unlock(&mtdblks_lock);
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DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
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@ -304,6 +311,8 @@ static int mtdblock_release(struct mtd_blktrans_dev *mbd)
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DEBUG(MTD_DEBUG_LEVEL1, "mtdblock_release\n");
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mutex_lock(&mtdblks_lock);
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mutex_lock(&mtdblk->cache_mutex);
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write_cached_data(mtdblk);
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mutex_unlock(&mtdblk->cache_mutex);
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@ -316,6 +325,9 @@ static int mtdblock_release(struct mtd_blktrans_dev *mbd)
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vfree(mtdblk->cache_data);
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kfree(mtdblk);
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}
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mutex_unlock(&mtdblks_lock);
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DEBUG(MTD_DEBUG_LEVEL1, "ok\n");
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return 0;
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@ -376,6 +388,8 @@ static struct mtd_blktrans_ops mtdblock_tr = {
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static int __init init_mtdblock(void)
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{
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mutex_init(&mtdblks_lock);
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return register_mtd_blktrans(&mtdblock_tr);
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}
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