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    Subject[POC 18/23] module: Refactor add_unformed_module()
    Date
    The livepatching code will need to add another condition to avoid
    waiting. Let's make the code slightly less hairy.

    Of course, it is a matter of taste. The main ideas of refactoring:

    + Make it clear what happens when old->state == MODULE_STATE_LIVE.

    + Make it more clear when we are leaving the function immediately
    and when we are doing some extra actions.

    + Be able to add another check that has to be done outside
    module_mutex and can result into an immediate return.

    Signed-off-by: Petr Mladek <pmladek@suse.com>
    ---
    kernel/module.c | 28 +++++++++++++++-------------
    1 file changed, 15 insertions(+), 13 deletions(-)

    diff --git a/kernel/module.c b/kernel/module.c
    index b3f11524f8f9..ac45d465ff23 100644
    --- a/kernel/module.c
    +++ b/kernel/module.c
    @@ -3721,28 +3721,30 @@ static int add_unformed_module(struct module *mod)
    again:
    mutex_lock(&module_mutex);
    old = find_module_all(mod->name, strlen(mod->name), true);
    +
    if (old != NULL) {
    - if (old->state != MODULE_STATE_LIVE) {
    - /* Wait in case it fails to load. */
    + if (old->state == MODULE_STATE_LIVE) {
    mutex_unlock(&module_mutex);
    - err = wait_event_interruptible(module_wq,
    - finished_loading(mod->name));
    - if (err)
    - goto out_unlocked;
    - goto again;
    + return -EEXIST;
    }
    - err = -EEXIST;
    - goto out;
    +
    + /* Wait in case it fails to load. */
    + mutex_unlock(&module_mutex);
    + err = wait_event_interruptible(module_wq,
    + finished_loading(mod->name));
    + if (err)
    + return err;
    +
    + /* Did the load succeded or failed? */
    + goto again;
    }
    +
    mod_update_bounds(mod);
    list_add_rcu(&mod->list, &modules);
    mod_tree_insert(mod);
    - err = 0;

    -out:
    mutex_unlock(&module_mutex);
    -out_unlocked:
    - return err;
    + return 0;
    }

    static int complete_formation(struct module *mod, struct load_info *info)
    --
    2.16.4
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