[U-Boot] [PATCH v3 3/3] mmc: Protect `mmc_initialize` from initilizing mmc multiple times

[Hans de Goede]

Hi,

On 29-05-15 16:55, Daniel Kochmański wrote:
> `mmc_initialize` might be called from various places and initializing
> list head of `mmc_devices` can lead to memory leaks.
>
> Signed-off-by: Daniel Kochmański <dkochmanski at turtle-solutions.eu>
> CC: Roy Spliet <r.spliet at ultimaker.com>
> Cc: Ian Campbell <ijc at hellion.org.uk>
> Cc: Hans De Goede <hdegoede at redhat.com>
> CC: Pantelis Antoniou <panto at antoniou-consulting.com>

Thanks I've merged this one into u-boot-sunxi/next, for inclusion
into u-boot v2015.10, I've fixed a few typos in the commit message
and clarified the commit message a bit.

Pantelis, since this is an mmc patch may we have your ack for this
one please? It is a dep for some sunxi changes so it is probably
easiest if I just merge it through the sunxi tree.

Some background, we are adding support for booting from nand,
and as such we need to make spl_boot_device() for sunxi
smarter. The sunxi BROM does not communicate where it has
loaded the SPL from, so we simply retrace it steps trying
mmc0 first and looking for a valid bootsignature there.

This means calling mmc_initialize() from spl_boot_device()
and if spl_boot_device() then finds a boot signature
and returns BOOT_DEVICE_MMC1, then later on
spl_mmc_load_image() will call mmc_initialize() a second
time, this patch protects against this second call and
turns the second call into a nop.

Regards,

Hans



> ---
>   drivers/mmc/mmc.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
> index 79e6fee..2959bde 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -1758,6 +1758,11 @@ static void do_preinit(void)
>
>   int mmc_initialize(bd_t *bis)
>   {
> +	static int initialized = 0;
> +	if (initialized)	/* Avoid initializing mmc multiple times */
> +		return 0;
> +	initialized = 1;
> +
>   	INIT_LIST_HEAD (&mmc_devices);
>   	cur_dev_num = 0;
>
>