Quoting Stephen Boyd (2014-09-05 17:00:00)
> On 09/04, Stephen Boyd wrote:
> >
> > I don't understand why we need to hold the prepare lock around
> > the kref_put(), so I changed the flow so that we don't do this
> > when we unregister a clock.
>
> Ok we hold the prepare mutex to make sure get and put are serialized.
> Good. Here's the interdiff to move the debugfs unregistration before
> the prepare lock and detect double unregisters without holding
> the prepare lock.
Looks good to me. I've rolled this into the original above and applied
it to clk-next.
Regards,
Mike
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 3c04d0d69b96..8ca28189e4e9 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -338,10 +338,14 @@ unlock:
> static void clk_debug_unregister(struct clk *clk)
> {
> mutex_lock(&clk_debug_lock);
> - hlist_del_init(&clk->debug_node);
> - mutex_unlock(&clk_debug_lock);
> + if (!clk->dentry)
> + goto out;
>
> + hlist_del_init(&clk->debug_node);
> debugfs_remove_recursive(clk->dentry);
> + clk->dentry = NULL;
> +out:
> + mutex_unlock(&clk_debug_lock);
> }
>
> struct dentry *clk_debugfs_add_file(struct clk *clk, char *name, umode_t mode,
> @@ -2065,14 +2069,15 @@ void clk_unregister(struct clk *clk)
> {
> unsigned long flags;
>
> - if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
> - return;
> + if (!clk || WARN_ON_ONCE(IS_ERR(clk)))
> + return;
> +
> + clk_debug_unregister(clk);
>
> clk_prepare_lock();
>
> if (clk->ops == &clk_nodrv_ops) {
> pr_err("%s: unregistered clock: %s\n", __func__, clk->name);
> - clk_prepare_unlock();
> return;
> }
> /*
> @@ -2097,11 +2102,9 @@ void clk_unregister(struct clk *clk)
> if (clk->prepare_count)
> pr_warn("%s: unregistering prepared clock: %s\n",
> __func__, clk->name);
> - clk_prepare_unlock();
> -
> - clk_debug_unregister(clk);
> -
> kref_put(&clk->ref, __clk_release);
> +
> + clk_prepare_unlock();
> }
> EXPORT_SYMBOL_GPL(clk_unregister);
>
> --
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> hosted by The Linux Foundation
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