Re: [PATCH 1/2] clk: abstract locking out into helper functions

[Ulf Hansson]

On 28 March 2013 21:59, Mike Turquette <mturquette@xxxxxxxxxx> wrote:
> Create locking helpers for the global mutex and global spinlock.  The
> definitions of these helpers will be expanded upon in the next patch
> which introduces reentrancy into the locking scheme.
>
> Signed-off-by: Mike Turquette <mturquette@xxxxxxxxxx>
> Cc: Rajagopal Venkat <rajagopal.venkat@xxxxxxxxxx>
> Cc: David Brown <davidb@xxxxxxxxxxxxxx>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Tested-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> ---
> Changes since v5:
>  * pass flags by value instead of by reference in clk_enable_{un}lock
>
>  drivers/clk/clk.c |   99 +++++++++++++++++++++++++++++++++--------------------
>  1 file changed, 61 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 5e8ffff..0b5d612 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -27,6 +27,29 @@ static HLIST_HEAD(clk_root_list);
>  static HLIST_HEAD(clk_orphan_list);
>  static LIST_HEAD(clk_notifier_list);
>
> +/***           locking             ***/
> +static void clk_prepare_lock(void)
> +{
> +       mutex_lock(&prepare_lock);
> +}
> +
> +static void clk_prepare_unlock(void)
> +{
> +       mutex_unlock(&prepare_lock);
> +}
> +
> +static unsigned long clk_enable_lock(void)
> +{
> +       unsigned long flags;
> +       spin_lock_irqsave(&enable_lock, flags);
> +       return flags;
> +}
> +
> +static void clk_enable_unlock(unsigned long flags)
> +{
> +       spin_unlock_irqrestore(&enable_lock, flags);
> +}
> +
>  /***        debugfs support        ***/
>
>  #ifdef CONFIG_COMMON_CLK_DEBUG
> @@ -69,7 +92,7 @@ static int clk_summary_show(struct seq_file *s, void *data)
>         seq_printf(s, "   clock                        enable_cnt  prepare_cnt  rate\n");
>         seq_printf(s, "---------------------------------------------------------------------\n");
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         hlist_for_each_entry(c, &clk_root_list, child_node)
>                 clk_summary_show_subtree(s, c, 0);
> @@ -77,7 +100,7 @@ static int clk_summary_show(struct seq_file *s, void *data)
>         hlist_for_each_entry(c, &clk_orphan_list, child_node)
>                 clk_summary_show_subtree(s, c, 0);
>
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return 0;
>  }
> @@ -130,7 +153,7 @@ static int clk_dump(struct seq_file *s, void *data)
>
>         seq_printf(s, "{");
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         hlist_for_each_entry(c, &clk_root_list, child_node) {
>                 if (!first_node)
> @@ -144,7 +167,7 @@ static int clk_dump(struct seq_file *s, void *data)
>                 clk_dump_subtree(s, c, 0);
>         }
>
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         seq_printf(s, "}");
>         return 0;
> @@ -316,7 +339,7 @@ static int __init clk_debug_init(void)
>         if (!orphandir)
>                 return -ENOMEM;
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         hlist_for_each_entry(clk, &clk_root_list, child_node)
>                 clk_debug_create_subtree(clk, rootdir);
> @@ -326,7 +349,7 @@ static int __init clk_debug_init(void)
>
>         inited = 1;
>
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return 0;
>  }
> @@ -372,7 +395,7 @@ static void clk_disable_unused_subtree(struct clk *clk)
>         hlist_for_each_entry(child, &clk->children, child_node)
>                 clk_disable_unused_subtree(child);
>
> -       spin_lock_irqsave(&enable_lock, flags);
> +       flags = clk_enable_lock();
>
>         if (clk->enable_count)
>                 goto unlock_out;
> @@ -393,7 +416,7 @@ static void clk_disable_unused_subtree(struct clk *clk)
>         }
>
>  unlock_out:
> -       spin_unlock_irqrestore(&enable_lock, flags);
> +       clk_enable_unlock(flags);
>
>  out:
>         return;
> @@ -403,7 +426,7 @@ static int clk_disable_unused(void)
>  {
>         struct clk *clk;
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         hlist_for_each_entry(clk, &clk_root_list, child_node)
>                 clk_disable_unused_subtree(clk);
> @@ -417,7 +440,7 @@ static int clk_disable_unused(void)
>         hlist_for_each_entry(clk, &clk_orphan_list, child_node)
>                 clk_unprepare_unused_subtree(clk);
>
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return 0;
>  }
> @@ -600,9 +623,9 @@ void __clk_unprepare(struct clk *clk)
>   */
>  void clk_unprepare(struct clk *clk)
>  {
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>         __clk_unprepare(clk);
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>  }
>  EXPORT_SYMBOL_GPL(clk_unprepare);
>
> @@ -648,9 +671,9 @@ int clk_prepare(struct clk *clk)
>  {
>         int ret;
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>         ret = __clk_prepare(clk);
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return ret;
>  }
> @@ -692,9 +715,9 @@ void clk_disable(struct clk *clk)
>  {
>         unsigned long flags;
>
> -       spin_lock_irqsave(&enable_lock, flags);
> +       flags = clk_enable_lock();
>         __clk_disable(clk);
> -       spin_unlock_irqrestore(&enable_lock, flags);
> +       clk_enable_unlock(flags);
>  }
>  EXPORT_SYMBOL_GPL(clk_disable);
>
> @@ -745,9 +768,9 @@ int clk_enable(struct clk *clk)
>         unsigned long flags;
>         int ret;
>
> -       spin_lock_irqsave(&enable_lock, flags);
> +       flags = clk_enable_lock();
>         ret = __clk_enable(clk);
> -       spin_unlock_irqrestore(&enable_lock, flags);
> +       clk_enable_unlock(flags);
>
>         return ret;
>  }
> @@ -792,9 +815,9 @@ long clk_round_rate(struct clk *clk, unsigned long rate)
>  {
>         unsigned long ret;
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>         ret = __clk_round_rate(clk, rate);
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return ret;
>  }
> @@ -889,13 +912,13 @@ unsigned long clk_get_rate(struct clk *clk)
>  {
>         unsigned long rate;
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
>                 __clk_recalc_rates(clk, 0);
>
>         rate = __clk_get_rate(clk);
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return rate;
>  }
> @@ -1100,7 +1123,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
>         int ret = 0;
>
>         /* prevent racing with updates to the clock topology */
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         /* bail early if nothing to do */
>         if (rate == clk->rate)
> @@ -1132,7 +1155,7 @@ int clk_set_rate(struct clk *clk, unsigned long rate)
>         clk_change_rate(top);
>
>  out:
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return ret;
>  }
> @@ -1148,9 +1171,9 @@ struct clk *clk_get_parent(struct clk *clk)
>  {
>         struct clk *parent;
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>         parent = __clk_get_parent(clk);
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return parent;
>  }
> @@ -1294,19 +1317,19 @@ static int __clk_set_parent(struct clk *clk, struct clk *parent)
>                 __clk_prepare(parent);
>
>         /* FIXME replace with clk_is_enabled(clk) someday */
> -       spin_lock_irqsave(&enable_lock, flags);
> +       flags = clk_enable_lock();
>         if (clk->enable_count)
>                 __clk_enable(parent);
> -       spin_unlock_irqrestore(&enable_lock, flags);
> +       clk_enable_unlock(flags);
>
>         /* change clock input source */
>         ret = clk->ops->set_parent(clk->hw, i);
>
>         /* clean up old prepare and enable */
> -       spin_lock_irqsave(&enable_lock, flags);
> +       flags = clk_enable_lock();
>         if (clk->enable_count)
>                 __clk_disable(old_parent);
> -       spin_unlock_irqrestore(&enable_lock, flags);
> +       clk_enable_unlock(flags);
>
>         if (clk->prepare_count)
>                 __clk_unprepare(old_parent);
> @@ -1338,7 +1361,7 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
>                 return -ENOSYS;
>
>         /* prevent racing with updates to the clock topology */
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         if (clk->parent == parent)
>                 goto out;
> @@ -1367,7 +1390,7 @@ int clk_set_parent(struct clk *clk, struct clk *parent)
>         __clk_reparent(clk, parent);
>
>  out:
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return ret;
>  }
> @@ -1390,7 +1413,7 @@ int __clk_init(struct device *dev, struct clk *clk)
>         if (!clk)
>                 return -EINVAL;
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         /* check to see if a clock with this name is already registered */
>         if (__clk_lookup(clk->name)) {
> @@ -1514,7 +1537,7 @@ int __clk_init(struct device *dev, struct clk *clk)
>         clk_debug_register(clk);
>
>  out:
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return ret;
>  }
> @@ -1748,7 +1771,7 @@ int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
>         if (!clk || !nb)
>                 return -EINVAL;
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         /* search the list of notifiers for this clk */
>         list_for_each_entry(cn, &clk_notifier_list, node)
> @@ -1772,7 +1795,7 @@ int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
>         clk->notifier_count++;
>
>  out:
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return ret;
>  }
> @@ -1797,7 +1820,7 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
>         if (!clk || !nb)
>                 return -EINVAL;
>
> -       mutex_lock(&prepare_lock);
> +       clk_prepare_lock();
>
>         list_for_each_entry(cn, &clk_notifier_list, node)
>                 if (cn->clk == clk)
> @@ -1818,7 +1841,7 @@ int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
>                 ret = -ENOENT;
>         }
>
> -       mutex_unlock(&prepare_lock);
> +       clk_prepare_unlock();
>
>         return ret;
>  }
> --
> 1.7.10.4
>

Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
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