2019-02-26 07:33:16

by Wei Yang

Subject: [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
to define the attribute.

Signed-off-by: Wei Yang <[email protected]>
---
drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
index 039e0f91dba8..a1293cbd7adb 100644
--- a/drivers/firmware/qemu_fw_cfg.c
+++ b/drivers/firmware/qemu_fw_cfg.c
@@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
return 0;
}

-static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
+static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
+ char *buf)
{
return sprintf(buf, "%u\n", fw_cfg_rev);
}
-
-static const struct {
- struct attribute attr;
- ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
-} fw_cfg_rev_attr = {
- .attr = { .name = "rev", .mode = S_IRUSR },
- .show = fw_cfg_showrev,
-};
+static const struct kobj_attribute fw_cfg_rev_attr =
+ __ATTR_RO_MODE(fw_cfg_rev, 0400);

/* fw_cfg_sysfs_entry type */
struct fw_cfg_sysfs_entry {
--
2.19.1

2019-02-26 16:11:07

by Michael S. Tsirkin

Subject: Re: [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On Tue, Feb 26, 2019 at 03:31:59PM +0800, Wei Yang wrote:
> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
> to define the attribute.
>
> Signed-off-by: Wei Yang <[email protected]>
> ---
> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index 039e0f91dba8..a1293cbd7adb 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> return 0;
> }
>
> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
> + char *buf)
> {
> return sprintf(buf, "%u\n", fw_cfg_rev);
> }
> -
> -static const struct {
> - struct attribute attr;
> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
> -} fw_cfg_rev_attr = {
> - .attr = { .name = "rev", .mode = S_IRUSR },
> - .show = fw_cfg_showrev,
> -};
> +static const struct kobj_attribute fw_cfg_rev_attr =
> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
>
> /* fw_cfg_sysfs_entry type */
> struct fw_cfg_sysfs_entry {


Looks like this will change the name from "rev" to "fw_cfg_rev".
That's a userspace visible change which we should not do lightly.
> --
> 2.19.1

2019-02-26 18:46:25

by Philippe Mathieu-Daudé

Subject: Re: [Qemu-devel] [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

Hi Wei,

On 2/26/19 8:31 AM, Wei Yang wrote:
> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
> to define the attribute.
>
> Signed-off-by: Wei Yang <[email protected]>
> ---
> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
> 1 file changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> index 039e0f91dba8..a1293cbd7adb 100644
> --- a/drivers/firmware/qemu_fw_cfg.c
> +++ b/drivers/firmware/qemu_fw_cfg.c
> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> return 0;
> }
>
> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
> + char *buf)
> {
> return sprintf(buf, "%u\n", fw_cfg_rev);
> }
> -
> -static const struct {
> - struct attribute attr;
> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
> -} fw_cfg_rev_attr = {
> - .attr = { .name = "rev", .mode = S_IRUSR },
> - .show = fw_cfg_showrev,
> -};
> +static const struct kobj_attribute fw_cfg_rev_attr =
> + __ATTR_RO_MODE(fw_cfg_rev, 0400);

Why not keep S_IRUSR?

>
> /* fw_cfg_sysfs_entry type */
> struct fw_cfg_sysfs_entry {
>

2019-02-26 18:49:04

by Philippe Mathieu-Daudé

Subject: Re: [Qemu-devel] [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On 2/26/19 5:10 PM, Michael S. Tsirkin wrote:
> On Tue, Feb 26, 2019 at 03:31:59PM +0800, Wei Yang wrote:
>> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
>> to define the attribute.
>>
>> Signed-off-by: Wei Yang <[email protected]>
>> ---
>> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
>> 1 file changed, 4 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
>> index 039e0f91dba8..a1293cbd7adb 100644
>> --- a/drivers/firmware/qemu_fw_cfg.c
>> +++ b/drivers/firmware/qemu_fw_cfg.c
>> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
>> return 0;
>> }
>>
>> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
>> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
>> + char *buf)
>> {
>> return sprintf(buf, "%u\n", fw_cfg_rev);
>> }
>> -
>> -static const struct {
>> - struct attribute attr;
>> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
>> -} fw_cfg_rev_attr = {
>> - .attr = { .name = "rev", .mode = S_IRUSR },
>> - .show = fw_cfg_showrev,
>> -};
>> +static const struct kobj_attribute fw_cfg_rev_attr =
>> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
>>
>> /* fw_cfg_sysfs_entry type */
>> struct fw_cfg_sysfs_entry {
>
>
> Looks like this will change the name from "rev" to "fw_cfg_rev".
> That's a userspace visible change which we should not do lightly.

We could name the function rev_show but this stay fragile, we'd also
need a comment "don't rename this".

>> --
>> 2.19.1
>

2019-02-26 18:50:50

by Michael S. Tsirkin

Subject: Re: [Qemu-devel] [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On Tue, Feb 26, 2019 at 07:47:35PM +0100, Philippe Mathieu-Daud? wrote:
> On 2/26/19 5:10 PM, Michael S. Tsirkin wrote:
> > On Tue, Feb 26, 2019 at 03:31:59PM +0800, Wei Yang wrote:
> >> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
> >> to define the attribute.
> >>
> >> Signed-off-by: Wei Yang <[email protected]>
> >> ---
> >> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
> >> 1 file changed, 4 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> >> index 039e0f91dba8..a1293cbd7adb 100644
> >> --- a/drivers/firmware/qemu_fw_cfg.c
> >> +++ b/drivers/firmware/qemu_fw_cfg.c
> >> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> >> return 0;
> >> }
> >>
> >> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
> >> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
> >> + char *buf)
> >> {
> >> return sprintf(buf, "%u\n", fw_cfg_rev);
> >> }
> >> -
> >> -static const struct {
> >> - struct attribute attr;
> >> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
> >> -} fw_cfg_rev_attr = {
> >> - .attr = { .name = "rev", .mode = S_IRUSR },
> >> - .show = fw_cfg_showrev,
> >> -};
> >> +static const struct kobj_attribute fw_cfg_rev_attr =
> >> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
> >>
> >> /* fw_cfg_sysfs_entry type */
> >> struct fw_cfg_sysfs_entry {
> >
> >
> > Looks like this will change the name from "rev" to "fw_cfg_rev".
> > That's a userspace visible change which we should not do lightly.
>
> We could name the function rev_show but this stay fragile, we'd also
> need a comment "don't rename this".

It's a given that one must not rename attributes.

> >> --
> >> 2.19.1
> >

2019-02-27 03:12:18

by Wei Yang

Subject: Re: [Qemu-devel] [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On Tue, Feb 26, 2019 at 07:45:46PM +0100, Philippe Mathieu-Daud? wrote:
>Hi Wei,
>
>On 2/26/19 8:31 AM, Wei Yang wrote:
>> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
>> to define the attribute.
>>
>> Signed-off-by: Wei Yang <[email protected]>
>> ---
>> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
>> 1 file changed, 4 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
>> index 039e0f91dba8..a1293cbd7adb 100644
>> --- a/drivers/firmware/qemu_fw_cfg.c
>> +++ b/drivers/firmware/qemu_fw_cfg.c
>> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
>> return 0;
>> }
>>
>> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
>> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
>> + char *buf)
>> {
>> return sprintf(buf, "%u\n", fw_cfg_rev);
>> }
>> -
>> -static const struct {
>> - struct attribute attr;
>> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
>> -} fw_cfg_rev_attr = {
>> - .attr = { .name = "rev", .mode = S_IRUSR },
>> - .show = fw_cfg_showrev,
>> -};
>> +static const struct kobj_attribute fw_cfg_rev_attr =
>> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
>
>Why not keep S_IRUSR?
>

Because scripts/checkpatch.pl suggest not use S_IRUSR :-)

I am not sure about the particular reason.

>>
>> /* fw_cfg_sysfs_entry type */
>> struct fw_cfg_sysfs_entry {
>>

--
Wei Yang
Help you, Help me

2019-02-27 05:35:33

by Wei Yang

Subject: Re: [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On Tue, Feb 26, 2019 at 11:10:06AM -0500, Michael S. Tsirkin wrote:
>On Tue, Feb 26, 2019 at 03:31:59PM +0800, Wei Yang wrote:
>> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
>> to define the attribute.
>>
>> Signed-off-by: Wei Yang <[email protected]>
>> ---
>> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
>> 1 file changed, 4 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
>> index 039e0f91dba8..a1293cbd7adb 100644
>> --- a/drivers/firmware/qemu_fw_cfg.c
>> +++ b/drivers/firmware/qemu_fw_cfg.c
>> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
>> return 0;
>> }
>>
>> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
>> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
>> + char *buf)
>> {
>> return sprintf(buf, "%u\n", fw_cfg_rev);
>> }
>> -
>> -static const struct {
>> - struct attribute attr;
>> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
>> -} fw_cfg_rev_attr = {
>> - .attr = { .name = "rev", .mode = S_IRUSR },
>> - .show = fw_cfg_showrev,
>> -};
>> +static const struct kobj_attribute fw_cfg_rev_attr =
>> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
>>
>> /* fw_cfg_sysfs_entry type */
>> struct fw_cfg_sysfs_entry {
>
>
>Looks like this will change the name from "rev" to "fw_cfg_rev".
>That's a userspace visible change which we should not do lightly.

You are right, I should keep the interface untouched.

To keep it user un-visible, we could change like below:

- __ATTR_RO(fw_cfg_rev);
+ __ATTR_RO(rev);

Is this better for you?

>> --
>> 2.19.1

--
Wei Yang
Help you, Help me

2019-02-27 14:33:48

by Michael S. Tsirkin

Subject: Re: [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On Wed, Feb 27, 2019 at 01:33:19PM +0800, Wei Yang wrote:
> On Tue, Feb 26, 2019 at 11:10:06AM -0500, Michael S. Tsirkin wrote:
> >On Tue, Feb 26, 2019 at 03:31:59PM +0800, Wei Yang wrote:
> >> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
> >> to define the attribute.
> >>
> >> Signed-off-by: Wei Yang <[email protected]>
> >> ---
> >> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
> >> 1 file changed, 4 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> >> index 039e0f91dba8..a1293cbd7adb 100644
> >> --- a/drivers/firmware/qemu_fw_cfg.c
> >> +++ b/drivers/firmware/qemu_fw_cfg.c
> >> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> >> return 0;
> >> }
> >>
> >> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
> >> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
> >> + char *buf)
> >> {
> >> return sprintf(buf, "%u\n", fw_cfg_rev);
> >> }
> >> -
> >> -static const struct {
> >> - struct attribute attr;
> >> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
> >> -} fw_cfg_rev_attr = {
> >> - .attr = { .name = "rev", .mode = S_IRUSR },
> >> - .show = fw_cfg_showrev,
> >> -};
> >> +static const struct kobj_attribute fw_cfg_rev_attr =
> >> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
> >>
> >> /* fw_cfg_sysfs_entry type */
> >> struct fw_cfg_sysfs_entry {
> >
> >
> >Looks like this will change the name from "rev" to "fw_cfg_rev".
> >That's a userspace visible change which we should not do lightly.
>
> You are right, I should keep the interface untouched.
>
> To keep it user un-visible, we could change like below:
>
> - __ATTR_RO(fw_cfg_rev);
> + __ATTR_RO(rev);
>
> Is this better for you?


Also why use 0400 and not S_IRUSR?

> >> --
> >> 2.19.1
>
> --
> Wei Yang
> Help you, Help me

2019-02-27 14:33:51

by Michael S. Tsirkin

Subject: Re: [Qemu-devel] [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On Wed, Feb 27, 2019 at 11:07:16AM +0800, Wei Yang wrote:
> On Tue, Feb 26, 2019 at 07:45:46PM +0100, Philippe Mathieu-Daud? wrote:
> >Hi Wei,
> >
> >On 2/26/19 8:31 AM, Wei Yang wrote:
> >> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
> >> to define the attribute.
> >>
> >> Signed-off-by: Wei Yang <[email protected]>
> >> ---
> >> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
> >> 1 file changed, 4 insertions(+), 9 deletions(-)
> >>
> >> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
> >> index 039e0f91dba8..a1293cbd7adb 100644
> >> --- a/drivers/firmware/qemu_fw_cfg.c
> >> +++ b/drivers/firmware/qemu_fw_cfg.c
> >> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
> >> return 0;
> >> }
> >>
> >> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
> >> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
> >> + char *buf)
> >> {
> >> return sprintf(buf, "%u\n", fw_cfg_rev);
> >> }
> >> -
> >> -static const struct {
> >> - struct attribute attr;
> >> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
> >> -} fw_cfg_rev_attr = {
> >> - .attr = { .name = "rev", .mode = S_IRUSR },
> >> - .show = fw_cfg_showrev,
> >> -};
> >> +static const struct kobj_attribute fw_cfg_rev_attr =
> >> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
> >
> >Why not keep S_IRUSR?
> >
>
> Because scripts/checkpatch.pl suggest not use S_IRUSR :-)
>
> I am not sure about the particular reason.

Oh yea.

http://lkml.kernel.org/r/CA+55aFw5v23T-zvDZp-MmD_EYxF8WbafwwB59934FV7g21uMGQ@mail.gmail.com

maybe mention this in the commit log.

> >>
> >> /* fw_cfg_sysfs_entry type */
> >> struct fw_cfg_sysfs_entry {
> >>
>
> --
> Wei Yang
> Help you, Help me

2019-02-27 14:44:28

by Wei Yang

Subject: Re: [Qemu-devel] [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On Wed, Feb 27, 2019 at 08:54:58AM -0500, Michael S. Tsirkin wrote:
>On Wed, Feb 27, 2019 at 11:07:16AM +0800, Wei Yang wrote:
>> On Tue, Feb 26, 2019 at 07:45:46PM +0100, Philippe Mathieu-Daud? wrote:
>> >Hi Wei,
>> >
>> >On 2/26/19 8:31 AM, Wei Yang wrote:
>> >> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
>> >> to define the attribute.
>> >>
>> >> Signed-off-by: Wei Yang <[email protected]>
>> >> ---
>> >> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
>> >> 1 file changed, 4 insertions(+), 9 deletions(-)
>> >>
>> >> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
>> >> index 039e0f91dba8..a1293cbd7adb 100644
>> >> --- a/drivers/firmware/qemu_fw_cfg.c
>> >> +++ b/drivers/firmware/qemu_fw_cfg.c
>> >> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
>> >> return 0;
>> >> }
>> >>
>> >> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
>> >> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
>> >> + char *buf)
>> >> {
>> >> return sprintf(buf, "%u\n", fw_cfg_rev);
>> >> }
>> >> -
>> >> -static const struct {
>> >> - struct attribute attr;
>> >> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
>> >> -} fw_cfg_rev_attr = {
>> >> - .attr = { .name = "rev", .mode = S_IRUSR },
>> >> - .show = fw_cfg_showrev,
>> >> -};
>> >> +static const struct kobj_attribute fw_cfg_rev_attr =
>> >> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
>> >
>> >Why not keep S_IRUSR?
>> >
>>
>> Because scripts/checkpatch.pl suggest not use S_IRUSR :-)
>>
>> I am not sure about the particular reason.
>
>Oh yea.
>
>http://lkml.kernel.org/r/CA+55aFw5v23T-zvDZp-MmD_EYxF8WbafwwB59934FV7g21uMGQ@mail.gmail.com
>
>maybe mention this in the commit log.
>

Thanks :-)

>> >>
>> >> /* fw_cfg_sysfs_entry type */
>> >> struct fw_cfg_sysfs_entry {
>> >>
>>
>> --
>> Wei Yang
>> Help you, Help me

--
Wei Yang
Help you, Help me

2019-02-27 15:19:19

by Wei Yang

Subject: Re: [Qemu-devel] [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On Wed, Feb 27, 2019 at 08:51:11AM -0500, Michael S. Tsirkin wrote:
>On Wed, Feb 27, 2019 at 01:33:19PM +0800, Wei Yang wrote:
>> On Tue, Feb 26, 2019 at 11:10:06AM -0500, Michael S. Tsirkin wrote:
>> >On Tue, Feb 26, 2019 at 03:31:59PM +0800, Wei Yang wrote:
>> >> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
>> >> to define the attribute.
>> >>
>> >> Signed-off-by: Wei Yang <[email protected]>
>> >> ---
>> >> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
>> >> 1 file changed, 4 insertions(+), 9 deletions(-)
>> >>
>> >> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
>> >> index 039e0f91dba8..a1293cbd7adb 100644
>> >> --- a/drivers/firmware/qemu_fw_cfg.c
>> >> +++ b/drivers/firmware/qemu_fw_cfg.c
>> >> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
>> >> return 0;
>> >> }
>> >>
>> >> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
>> >> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
>> >> + char *buf)
>> >> {
>> >> return sprintf(buf, "%u\n", fw_cfg_rev);
>> >> }
>> >> -
>> >> -static const struct {
>> >> - struct attribute attr;
>> >> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
>> >> -} fw_cfg_rev_attr = {
>> >> - .attr = { .name = "rev", .mode = S_IRUSR },
>> >> - .show = fw_cfg_showrev,
>> >> -};
>> >> +static const struct kobj_attribute fw_cfg_rev_attr =
>> >> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
>> >>
>> >> /* fw_cfg_sysfs_entry type */
>> >> struct fw_cfg_sysfs_entry {
>> >
>> >
>> >Looks like this will change the name from "rev" to "fw_cfg_rev".
>> >That's a userspace visible change which we should not do lightly.
>>
>> You are right, I should keep the interface untouched.
>>
>> To keep it user un-visible, we could change like below:
>>
>> - __ATTR_RO(fw_cfg_rev);
>> + __ATTR_RO(rev);
>>
>> Is this better for you?
>
>
>Also why use 0400 and not S_IRUSR?
>

This is interesting. The scripts/checkpatch.pl suggest to use 0400.

I am not sure why the script give this suggestion. Maybe we need to fix
the script?

>> >> --
>> >> 2.19.1
>>
>> --
>> Wei Yang
>> Help you, Help me

--
Wei Yang
Help you, Help me

2019-02-28 00:50:26

by Wei Yang

Subject: Re: [PATCH] fw_cfg: use __ATTR_RO_MODE to define rev sysfs

On Wed, Feb 27, 2019 at 08:51:11AM -0500, Michael S. Tsirkin wrote:
>On Wed, Feb 27, 2019 at 01:33:19PM +0800, Wei Yang wrote:
>> On Tue, Feb 26, 2019 at 11:10:06AM -0500, Michael S. Tsirkin wrote:
>> >On Tue, Feb 26, 2019 at 03:31:59PM +0800, Wei Yang wrote:
>> >> Leverage __ATTR_RO_MODE to define rev sysfs instead of using open code
>> >> to define the attribute.
>> >>
>> >> Signed-off-by: Wei Yang <[email protected]>
>> >> ---
>> >> drivers/firmware/qemu_fw_cfg.c | 13 ++++---------
>> >> 1 file changed, 4 insertions(+), 9 deletions(-)
>> >>
>> >> diff --git a/drivers/firmware/qemu_fw_cfg.c b/drivers/firmware/qemu_fw_cfg.c
>> >> index 039e0f91dba8..a1293cbd7adb 100644
>> >> --- a/drivers/firmware/qemu_fw_cfg.c
>> >> +++ b/drivers/firmware/qemu_fw_cfg.c
>> >> @@ -296,18 +296,13 @@ static int fw_cfg_do_platform_probe(struct platform_device *pdev)
>> >> return 0;
>> >> }
>> >>
>> >> -static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
>> >> +static ssize_t fw_cfg_rev_show(struct kobject *k, struct kobj_attribute *a,
>> >> + char *buf)
>> >> {
>> >> return sprintf(buf, "%u\n", fw_cfg_rev);
>> >> }
>> >> -
>> >> -static const struct {
>> >> - struct attribute attr;
>> >> - ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
>> >> -} fw_cfg_rev_attr = {
>> >> - .attr = { .name = "rev", .mode = S_IRUSR },
>> >> - .show = fw_cfg_showrev,
>> >> -};
>> >> +static const struct kobj_attribute fw_cfg_rev_attr =
>> >> + __ATTR_RO_MODE(fw_cfg_rev, 0400);
>> >>
>> >> /* fw_cfg_sysfs_entry type */
>> >> struct fw_cfg_sysfs_entry {
>> >
>> >
>> >Looks like this will change the name from "rev" to "fw_cfg_rev".
>> >That's a userspace visible change which we should not do lightly.
>>
>> You are right, I should keep the interface untouched.
>>
>> To keep it user un-visible, we could change like below:
>>
>> - __ATTR_RO(fw_cfg_rev);
>> + __ATTR_RO(rev);
>>
>> Is this better for you?
>
>
>Also why use 0400 and not S_IRUSR?
>

In case this is the proper way to use 0400 and after keeping the name
un-changed, would you mind I sending v2 for this?

>> >> --
>> >> 2.19.1
>>
>> --
>> Wei Yang
>> Help you, Help me

--
Wei Yang
Help you, Help me