[PATCH v13 3/6] clk: Make clk API return per-user struct clk instances
From: Stephen Boyd <hidden>
Date: 2015-02-05 20:07:11
Also in:
linux-omap, lkml
Subsystem:
arm/clkdev support, the rest · Maintainers:
Russell King, Linus Torvalds
On 02/05/15 11:44, Sylwester Nawrocki wrote:
Hi Tomeu, On 23/01/15 12:03, Tomeu Vizoso wrote:quoted
int __clk_get(struct clk *clk) { - if (clk) { - if (!try_module_get(clk->owner)) + struct clk_core *core = !clk ? NULL : clk->core; + + if (core) { + if (!try_module_get(core->owner)) return 0; - kref_get(&clk->ref); + kref_get(&core->ref); } return 1; } -void __clk_put(struct clk *clk) +static void clk_core_put(struct clk_core *core) { struct module *owner; - if (!clk || WARN_ON_ONCE(IS_ERR(clk))) - return; + owner = core->owner; clk_prepare_lock(); - owner = clk->owner; - kref_put(&clk->ref, __clk_release); + kref_put(&core->ref, __clk_release); clk_prepare_unlock(); module_put(owner); } +void __clk_put(struct clk *clk) +{ + if (!clk || WARN_ON_ONCE(IS_ERR(clk))) + return; + + clk_core_put(clk->core); + kfree(clk);Why do we have kfree() here? clk_get() doesn't allocate the data structure being freed here. What happens if we do clk_get(), clk_put(), clk_get() on same clock? I suspect __clk_free_clk() should be called in __clk_release() callback instead, but then there is an issue of safely getting reference to struct clk from struct clk_core pointer. I tested linux-next on Odroid U3 and booting fails with oopses as below. There is no problems when the above kfree() is commented out.
Ah now I get it. You meant to say that of_clk_get_by_clkspec() doesn't return an allocated clk pointer. Let's fix that. ----8<---- From: Stephen Boyd <redacted> Subject: [PATCH] clkdev: Always allocate a struct clk in OF functions of_clk_get_by_clkspec() returns a struct clk pointer but it doesn't create a new handle for the consumers. Instead it just returns whatever the OF clk provider hands out. Let's create a per-user handle here so that clk_put() can properly unlink it and free it when the consumer is done. Fixes: 035a61c314eb "clk: Make clk API return per-user struct clk instances" Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com> Signed-off-by: Stephen Boyd <redacted> --- drivers/clk/clkdev.c | 44 +++++++++++++++++++++++--------------------- 1 file changed, 23 insertions(+), 21 deletions(-)
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 29a1ab7af4b8..00d747d09b2a 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c@@ -29,15 +29,8 @@ static DEFINE_MUTEX(clocks_mutex); #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) -/** - * of_clk_get_by_clkspec() - Lookup a clock form a clock provider - * @clkspec: pointer to a clock specifier data structure - * - * This function looks up a struct clk from the registered list of clock - * providers, an input is a clock specifier data structure as returned - * from the of_parse_phandle_with_args() function call. - */ -struct clk *of_clk_get_by_clkspec(struct of_phandle_args *clkspec) +static struct clk *__of_clk_get_by_clkspec(struct of_phandle_args *clkspec, + const char *dev_id, const char *con_id) { struct clk *clk;
@@ -47,6 +40,8 @@ struct clk *of_clk_get_by_clkspec(struct of_phandle_args *clkspec) of_clk_lock(); clk = __of_clk_get_from_provider(clkspec); + if (!IS_ERR(clk)) + clk = __clk_create_clk(__clk_get_hw(clk), dev_id, con_id); if (!IS_ERR(clk) && !__clk_get(clk)) clk = ERR_PTR(-ENOENT);
@@ -54,7 +49,21 @@ struct clk *of_clk_get_by_clkspec(struct of_phandle_args *clkspec) return clk; } -static struct clk *__of_clk_get(struct device_node *np, int index) +/** + * of_clk_get_by_clkspec() - Lookup a clock form a clock provider + * @clkspec: pointer to a clock specifier data structure + * + * This function looks up a struct clk from the registered list of clock + * providers, an input is a clock specifier data structure as returned + * from the of_parse_phandle_with_args() function call. + */ +struct clk *of_clk_get_by_clkspec(struct of_phandle_args *clkspec) +{ + return __of_clk_get_by_clkspec(clkspec, NULL, __func__); +} + +static struct clk *__of_clk_get(struct device_node *np, int index, + const char *dev_id, const char *con_id) { struct of_phandle_args clkspec; struct clk *clk;
@@ -68,7 +77,7 @@ static struct clk *__of_clk_get(struct device_node *np, int index) if (rc) return ERR_PTR(rc); - clk = of_clk_get_by_clkspec(&clkspec); + clk = __of_clk_get_by_clkspec(&clkspec, dev_id, con_id); of_node_put(clkspec.np); return clk;
@@ -76,12 +85,7 @@ static struct clk *__of_clk_get(struct device_node *np, int index) struct clk *of_clk_get(struct device_node *np, int index) { - struct clk *clk = __of_clk_get(np, index); - - if (!IS_ERR(clk)) - clk = __clk_create_clk(__clk_get_hw(clk), np->full_name, NULL); - - return clk; + return __of_clk_get(np, index, np->full_name, NULL); } EXPORT_SYMBOL(of_clk_get);
@@ -102,12 +106,10 @@ static struct clk *__of_clk_get_by_name(struct device_node *np, */ if (name) index = of_property_match_string(np, "clock-names", name); - clk = __of_clk_get(np, index); + clk = __of_clk_get(np, index, dev_id, name); if (!IS_ERR(clk)) { - clk = __clk_create_clk(__clk_get_hw(clk), dev_id, name); break; - } - else if (name && index >= 0) { + } else if (name && index >= 0) { if (PTR_ERR(clk) != -EPROBE_DEFER) pr_err("ERROR: could not get clock %s:%s(%i)\n", np->full_name, name ? name : "", index);
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