On 28/12/11 12:46, Shashidhar hiremath wrote:
> From: Shashidhar Hiremath <shashidharh@xxxxxxxxxxxxxxx>
>
> The Patch adds a check to disable the IOCTL from running when the card is mounted
> or device is opened elsewhere.
What if someone wants to do that.
Generally the kernel does not prevent access to raw block devices
just because a file system is mounted on them, so I guess MMC should
not either.
>
> Signed-off-by: Shashidhar Hiremath <shashidharh@xxxxxxxxxxxxxxx>
> ---
> drivers/mmc/card/block.c | 6 ++++++
> 1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 0cad48a..e680929 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -387,6 +387,12 @@ static int mmc_blk_ioctl_cmd(struct block_device *bdev,
> err = -EINVAL;
> goto cmd_done;
> }
> + /* Disallow the IOCTL run if card is already mounted or device is
> + * opened elsewhere */
> + if (md->usage > 3) {
> + err = -EINVAL;
> + goto cmd_done;
> + }
Checking the usage will not work consistently e.g.
if there is a sysfs access or another ioctl access at the
same time, or just some other kernel user of the device.
>
> card = md->queue.card;
> if (IS_ERR(card)) {
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