[Cocci] [PATCH v13 3/6] clk: Make clk API return per-user struct clk instances

Hello,
Julia asked me to have a look and see if I can help.

On 02/02/2015 23:50, Mike Turquette wrote:

Quoting Stephen Boyd (2015-02-02 14:35:59)

quoted

On 02/02/15 13:31, Julia Lawall wrote:

quoted

On Mon, 2 Feb 2015, Stephen Boyd wrote:

quoted

Julia,

Is there a way we can write a coccinelle script to check for this? The
goal being to find all drivers that are comparing struct clk pointers or
attempting to dereference them. There are probably other frameworks that
could use the same type of check (regulator, gpiod, reset, pwm, etc.).
Probably anything that has a get/put API.

Comparing or dereferencing pointers of a particular type should be
straightforward to check for.  Is there an example of how to use the
parent_index value to fix the problem?

I'm not sure how to fix this case with parent_index values generically.
I imagine it would be highly specific to the surrounding code to the
point where we couldn't fix it automatically. For example, if it's a clk
consumer (not provider like in this case) using an index wouldn't be the
right fix. We would need some sort of clk API that we don't currently
have and I would wonder why clock consumers even care to compare such
pointers in the first place.

Ack. Is there precedent for a "Don't do that" kind of response?

Regards,
Mike

quoted

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I have found these three cases using Coccinnelle in the mach-omap2
directory.



./arch/arm/mach-omap2/clkt_clksel.c

@@ -67,7 +67,6 @@ static const struct clksel *_get_clksel_
                 return NULL;

         for (clks = clk->clksel; clks->parent; clks++)
                 if (clks->parent == src_clk)
                         break; /* Found the requested parent */

         if (!clks->parent) {

./arch/arm/mach-omap2/dpll3xxx.c

@@ -551,7 +549,6 @@ int omap3_noncore_dpll_set_rate(struct c
         if (!dd)
                 return -EINVAL;

         if (__clk_get_parent(hw->clk) != dd->clk_ref)
                 return -EINVAL;

         if (dd->last_rounded_rate == 0)

./arch/arm/mach-omap2/timer.c

@@ -298,7 +298,6 @@ static int __init omap_dm_timer_init_one
         if (IS_ERR(src))
                 return PTR_ERR(src);

         if (clk_get_parent(timer->fclk) != src) {
                 r = clk_set_parent(timer->fclk, src);
                 if (r < 0) {
                         pr_warn("%s: %s cannot set source\n", __func__,

Are they instances of your issue?
Do you have any suggestion on how to fix them?
If you want me to I can enlarge the search to other directories.


Quentin