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authorMatthias Kaehlcke <matthias@kaehlcke.net>2009-07-14 22:04:29 +0200
committerDavid Woodhouse <David.Woodhouse@intel.com>2009-08-03 14:25:00 +0100
commitd676c11727815761e41a81b00c054b4bec452ae5 (patch)
tree9cdc40a1142010a545e41272a0c3b5ddc0d205fc /drivers/mtd/mtdblock.c
parent2bf961b7ccd69e108ac435c67e2b0522b403c578 (diff)
downloadlinaro-lsk-d676c11727815761e41a81b00c054b4bec452ae5.tar.gz
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>
Diffstat (limited to 'drivers/mtd/mtdblock.c')
-rw-r--r--drivers/mtd/mtdblock.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
index 208c6faa035..77db5ce24d9 100644
--- a/drivers/mtd/mtdblock.c
+++ b/drivers/mtd/mtdblock.c
@@ -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);
}