-Deny use of a char mtd device to map as block device.
-mutex_init when mtd structure is available.
-fixme applied : check device size is a multiple of erasesize.
-mutex_destroy on each device in block2mtd_exit and add_device failure.

Signed-off-by: Fabian Frederick <f...@skynet.be>
---
 drivers/mtd/devices/block2mtd.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c
index d9fd87a..be67731 100644
--- a/drivers/mtd/devices/block2mtd.c
+++ b/drivers/mtd/devices/block2mtd.c
@@ -209,7 +209,6 @@ static void block2mtd_free_device(struct block2mtd_dev *dev)
 }
 
 
-/* FIXME: ensure that mtd->size % erase_size == 0 */
 static struct block2mtd_dev *add_device(char *devname, int erase_size)
 {
        const fmode_t mode = FMODE_READ | FMODE_WRITE | FMODE_EXCL;
@@ -244,21 +243,27 @@ static struct block2mtd_dev *add_device(char *devname, 
int erase_size)
        }
        dev->blkdev = bdev;
 
-       if (MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) {
+       if ((MAJOR(bdev->bd_dev) == MTD_BLOCK_MAJOR) ||
+           (MAJOR(bdev->bd_dev) == MTD_CHAR_MAJOR)) {
                pr_err("attempting to use an MTD device as a block device\n");
                goto devinit_err;
        }
 
-       mutex_init(&dev->write_mutex);
 
        /* Setup the MTD structure */
        /* make the name contain the block device in */
        name = kasprintf(GFP_KERNEL, "block2mtd: %s", devname);
+
        if (!name)
                goto devinit_err;
+
+       if ((long)dev->blkdev->bd_inode->i_size % erase_size) {
+               pr_err("erasesize must be a divisor of device size\n");
+               goto devinit_err;
+       }
 
+       mutex_init(&dev->write_mutex);
        dev->mtd.name = name;
-
        dev->mtd.size = dev->blkdev->bd_inode->i_size & PAGE_MASK;
        dev->mtd.erasesize = erase_size;
        dev->mtd.writesize = 1;
@@ -274,7 +279,7 @@ static struct block2mtd_dev *add_device(char *devname, int 
erase_size)
 
        if (mtd_device_register(&dev->mtd, NULL, 0)) {
                /* Device didn't get added, so free the entry */
-               goto devinit_err;
+               goto register_err;
        }
        list_add(&dev->list, &blkmtd_device_list);
        pr_info("mtd%d: [%s] erase_size = %dKiB [%d]\n",
@@ -283,6 +288,8 @@ static struct block2mtd_dev *add_device(char *devname, int 
erase_size)
                dev->mtd.erasesize >> 10, dev->mtd.erasesize);
        return dev;
 
+register_err:
+       mutex_destroy(&dev->write_mutex);
 devinit_err:
        block2mtd_free_device(dev);
        return NULL;
@@ -448,6 +455,7 @@ static void block2mtd_exit(void)
                struct block2mtd_dev *dev = list_entry(pos, typeof(*dev), list);
                block2mtd_sync(&dev->mtd);
                mtd_device_unregister(&dev->mtd);
+               mutex_destroy(&dev->write_mutex);
                pr_info("mtd%d: [%s] removed\n",
                        dev->mtd.index,
                        dev->mtd.name + strlen("block2mtd: "));
-- 
1.8.1.4
--
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