Existing check of `fn` against NULL inside OF match table
is redundant. Remove the check.
Signed-off-by: Mukesh Ojha <[email protected]>
Cc: Rob Herring <[email protected]>
Cc: Frank Rowand <[email protected]>
Cc: Pantelis Antoniou <[email protected]>
Cc: [email protected]
---
include/linux/of.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/of.h b/include/linux/of.h
index e240992..b86c00a 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1283,13 +1283,13 @@ static inline int of_get_available_child_count(const struct device_node *np)
static const struct of_device_id __of_table_##name \
__used __section(__##table##_of_table) \
= { .compatible = compat, \
- .data = (fn == (fn_type)NULL) ? fn : fn }
+ .data = fn }
#else
#define _OF_DECLARE(table, name, compat, fn, fn_type) \
static const struct of_device_id __of_table_##name \
__attribute__((unused)) \
= { .compatible = compat, \
- .data = (fn == (fn_type)NULL) ? fn : fn }
+ .data = fn }
#endif
typedef int (*of_init_fn_2)(struct device_node *, struct device_node *);
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center,
Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project
On 3/20/19 3:49 AM, Mukesh Ojha wrote:
> Existing check of `fn` against NULL inside OF match table
> is redundant. Remove the check.
>
> Signed-off-by: Mukesh Ojha <[email protected]>
> Cc: Rob Herring <[email protected]>
> Cc: Frank Rowand <[email protected]>
> Cc: Pantelis Antoniou <[email protected]>
> Cc: [email protected]
> ---
> include/linux/of.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/of.h b/include/linux/of.h
> index e240992..b86c00a 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -1283,13 +1283,13 @@ static inline int of_get_available_child_count(const struct device_node *np)
> static const struct of_device_id __of_table_##name \
> __used __section(__##table##_of_table) \
> = { .compatible = compat, \
> - .data = (fn == (fn_type)NULL) ? fn : fn }
> + .data = fn }
> #else
> #define _OF_DECLARE(table, name, compat, fn, fn_type) \
> static const struct of_device_id __of_table_##name \
> __attribute__((unused)) \
> = { .compatible = compat, \
> - .data = (fn == (fn_type)NULL) ? fn : fn }
> + .data = fn }
> #endif
>
> typedef int (*of_init_fn_2)(struct device_node *, struct device_node *);
>
The check is not redundant and does serve a purpose.
The purpose is not very obvious on the surface, but it is checking that
the function fn() is of the proper type.
An example of a compiler warning with a bad function type is created
by applying the following patch:
drivers/of/unittest.c:62:1: warning: comparison of distinct pointer types lacks a cast [enabled by default]
Note that you need to have CONFIG_UNITTEST enabled to compile unittest.c.
Line 62 is
OF_DECLARE_1(__unittest_of_table, unittest_setup_2_bad, "unittest_compat",
---
drivers/of/unittest.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
Index: b/drivers/of/unittest.c
===================================================================
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -45,6 +45,23 @@ static struct unittest_results {
failed; \
})
+struct of_device_id __unittest_of_table;
+
+static void __init unittest_setup_1_good(struct device_node *np)
+{
+}
+
+static void __init unittest_setup_2_bad(struct device_node *np_1,
+ struct device_node *np_2)
+{
+}
+
+OF_DECLARE_1(__unittest_of_table, unittest_setup_1_good, "unittest_compat",
+ unittest_setup_1_good);
+
+OF_DECLARE_1(__unittest_of_table, unittest_setup_2_bad, "unittest_compat",
+ unittest_setup_2_bad);
+
static void __init of_unittest_find_node_by_name(void)
{
struct device_node *np;
On 3/21/2019 1:25 AM, Frank Rowand wrote:
> On 3/20/19 3:49 AM, Mukesh Ojha wrote:
>> Existing check of `fn` against NULL inside OF match table
>> is redundant. Remove the check.
>>
>> Signed-off-by: Mukesh Ojha <[email protected]>
>> Cc: Rob Herring <[email protected]>
>> Cc: Frank Rowand <[email protected]>
>> Cc: Pantelis Antoniou <[email protected]>
>> Cc: [email protected]
>> ---
>> include/linux/of.h | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/include/linux/of.h b/include/linux/of.h
>> index e240992..b86c00a 100644
>> --- a/include/linux/of.h
>> +++ b/include/linux/of.h
>> @@ -1283,13 +1283,13 @@ static inline int of_get_available_child_count(const struct device_node *np)
>> static const struct of_device_id __of_table_##name \
>> __used __section(__##table##_of_table) \
>> = { .compatible = compat, \
>> - .data = (fn == (fn_type)NULL) ? fn : fn }
>> + .data = fn }
>> #else
>> #define _OF_DECLARE(table, name, compat, fn, fn_type) \
>> static const struct of_device_id __of_table_##name \
>> __attribute__((unused)) \
>> = { .compatible = compat, \
>> - .data = (fn == (fn_type)NULL) ? fn : fn }
>> + .data = fn }
>> #endif
>>
>> typedef int (*of_init_fn_2)(struct device_node *, struct device_node *);
>>
> The check is not redundant and does serve a purpose.
>
> The purpose is not very obvious on the surface, but it is checking that
> the function fn() is of the proper type.
Frank,
Thanks for taking out time to explain the stuff, Yeah some miscellaneous
driver can do this type of mistake.
-Mukesh
> An example of a compiler warning with a bad function type is created
> by applying the following patch:
>
> drivers/of/unittest.c:62:1: warning: comparison of distinct pointer types lacks a cast [enabled by default]
>
> Note that you need to have CONFIG_UNITTEST enabled to compile unittest.c.
>
> Line 62 is
> OF_DECLARE_1(__unittest_of_table, unittest_setup_2_bad, "unittest_compat",
>
> ---
> drivers/of/unittest.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> Index: b/drivers/of/unittest.c
> ===================================================================
> --- a/drivers/of/unittest.c
> +++ b/drivers/of/unittest.c
> @@ -45,6 +45,23 @@ static struct unittest_results {
> failed; \
> })
>
> +struct of_device_id __unittest_of_table;
> +
> +static void __init unittest_setup_1_good(struct device_node *np)
> +{
> +}
> +
> +static void __init unittest_setup_2_bad(struct device_node *np_1,
> + struct device_node *np_2)
> +{
> +}
> +
> +OF_DECLARE_1(__unittest_of_table, unittest_setup_1_good, "unittest_compat",
> + unittest_setup_1_good);
> +
> +OF_DECLARE_1(__unittest_of_table, unittest_setup_2_bad, "unittest_compat",
> + unittest_setup_2_bad);
> +
> static void __init of_unittest_find_node_by_name(void)
> {
> struct device_node *np;