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Message-ID: <CAPDyKFphM60Z=W9PNR3=gSXF61_0eTPWYqcKubnzQSFeYabvRg@mail.gmail.com>
Date: Tue, 2 Apr 2013 11:23:47 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Mike Turquette <mturquette@...aro.org>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
patches@...aro.org, linaro-kernel@...ts.linaro.org,
rajagopal.venkat@...aro.org, davidb@...eaurora.org,
laurent.pinchart@...asonboard.com, tglx@...utronix.de
Subject: Re: [PATCH 1/2] clk: abstract locking out into helper functions
On 28 March 2013 21:59, Mike Turquette <mturquette@...aro.org> 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@...aro.org>
> Cc: Rajagopal Venkat <rajagopal.venkat@...aro.org>
> Cc: David Brown <davidb@...eaurora.org>
> Cc: Ulf Hansson <ulf.hansson@...aro.org>
> Tested-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> Reviewed-by: Thomas Gleixner <tglx@...utronix.de>
> ---
> 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@...aro.org>
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