On Mon, Oct 04 2021 at 4:06P -0400,
Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> wrote:
> dm_get_target_type() doesn't check error return from request_module().
> Change to check for error and return NULL instead of trying to get
> target type again which would fail.
>
> Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/md/dm-target.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c
> index 64dd0b34fcf4..0789e9f91d3a 100644
> --- a/drivers/md/dm-target.c
> +++ b/drivers/md/dm-target.c
> @@ -41,17 +41,22 @@ static struct target_type *get_target_type(const char *name)
> return tt;
> }
>
> -static void load_module(const char *name)
> +static int load_module(const char *name)
> {
> - request_module("dm-%s", name);
> + return request_module("dm-%s", name);
> }
>
> struct target_type *dm_get_target_type(const char *name)
> {
> struct target_type *tt = get_target_type(name);
> + int ret;
>
> if (!tt) {
> - load_module(name);
> + ret = load_module(name);
> + if (ret < 0) {
> + pr_err("Module %s load failed %d\n", name, ret);
> + return NULL;
> + }
> tt = get_target_type(name);
> }
>
> --
> 2.30.2
>
While I appreciate your intent, the reality is that multiple targets
may be made available in a given module. And so loading one dm module
may bring in access to N targets. There isn't a rigid 1:1 mapping of
target modules to names. And there may not even be a loadable module
that has the name dm-${name} -- but that doesn't mean the target_type
won;t have been loaded into DM for it to access.
So all said, your patch is bogus and would break DM and user
experience:
Nacked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
But thanks for raising your concern.
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