2022-10-19 15:09:10

by John Ogness

Subject: [PATCH printk v2 09/38] netconsole: use console_is_enabled()

Replace (console->flags & CON_ENABLED) usage with console_is_enabled().

Signed-off-by: John Ogness <[email protected]>
---
drivers/net/netconsole.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index bdff9ac5056d..073e59a06f21 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -332,7 +332,7 @@ static ssize_t enabled_store(struct config_item *item,
}

if (enabled) { /* true */
- if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) {
+ if (nt->extended && !console_is_enabled(&netconsole_ext)) {
netconsole_ext.flags |= CON_ENABLED;
register_console(&netconsole_ext);
}
@@ -915,7 +915,7 @@ static int __init init_netconsole(void)
if (err)
goto undonotifier;

- if (netconsole_ext.flags & CON_ENABLED)
+ if (console_is_enabled(&netconsole_ext))
register_console(&netconsole_ext);
register_console(&netconsole);
pr_info("network logging started\n");
--
2.30.2

2022-10-21 13:40:03

by Petr Mladek

Subject: Re: [PATCH printk v2 09/38] netconsole: use console_is_enabled()

On Wed 2022-10-19 17:01:31, John Ogness wrote:
> Replace (console->flags & CON_ENABLED) usage with console_is_enabled().
>
> Signed-off-by: John Ogness <[email protected]>

The change is straightforward:

Reviewed-by: Petr Mladek <[email protected]>

The comment below is just a lamentation about the netconsole code.

> ---
> drivers/net/netconsole.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
> index bdff9ac5056d..073e59a06f21 100644
> --- a/drivers/net/netconsole.c
> +++ b/drivers/net/netconsole.c
> @@ -332,7 +332,7 @@ static ssize_t enabled_store(struct config_item *item,
> }
>
> if (enabled) { /* true */
> - if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) {
> + if (nt->extended && !console_is_enabled(&netconsole_ext)) {
> netconsole_ext.flags |= CON_ENABLED;
> register_console(&netconsole_ext);
> }
> @@ -915,7 +915,7 @@ static int __init init_netconsole(void)
> if (err)
> goto undonotifier;
>
> - if (netconsole_ext.flags & CON_ENABLED)
> + if (console_is_enabled(&netconsole_ext))
> register_console(&netconsole_ext);
> register_console(&netconsole);
> pr_info("network logging started\n");

Just for record:

This looks like a (mis)use of CON_ENABLED flag. It took me some time
to understand why pre-enabled consoles are handled special way in
register_console(). I partly documented it in
try_enable_preferred_console():

/*
* Some consoles, such as pstore and netconsole, can be enabled even
* without matching. Accept the pre-enabled consoles only when match()
* and setup() had a chance to be called.
*/
if (console_is_enabled(newcon) && (c->user_specified == user_specified))
return 0;

In my bottom driver, I have a patch cleaning this. It is part of a bigger
clean up that is not ready for upstream :-/

Best Regards,
Petr

2022-11-04 15:28:56

by John Ogness

Subject: Re: [PATCH printk v2 09/38] netconsole: use console_is_enabled()

On 2022-10-21, Petr Mladek <[email protected]> wrote:
>> diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
>> index bdff9ac5056d..073e59a06f21 100644
>> --- a/drivers/net/netconsole.c
>> +++ b/drivers/net/netconsole.c
>> @@ -332,7 +332,7 @@ static ssize_t enabled_store(struct config_item *item,
>> }
>>
>> if (enabled) { /* true */
>> - if (nt->extended && !(netconsole_ext.flags & CON_ENABLED)) {
>> + if (nt->extended && !console_is_enabled(&netconsole_ext)) {
>> netconsole_ext.flags |= CON_ENABLED;
>> register_console(&netconsole_ext);
>> }
>> @@ -915,7 +915,7 @@ static int __init init_netconsole(void)
>> if (err)
>> goto undonotifier;
>>
>> - if (netconsole_ext.flags & CON_ENABLED)
>> + if (console_is_enabled(&netconsole_ext))
>> register_console(&netconsole_ext);
>> register_console(&netconsole);
>> pr_info("network logging started\n");
>
> This looks like a (mis)use of CON_ENABLED flag.

Yes. When @netconsole_ext is registered, CON_ENABLED is always set. So
it should be set in the static initialization. The first hunk should be
using the new console_is_registered(). The second hunk should be using a
local @extended bool variable. Also, in cleanup_netconsole() it should
check if the console is registered:

if (console_is_registered(&netconsole_ext))
unregister_console(&netconsole_ext);

I will make all of these changes for v3. Then there will be no
checking/setting of CON_ENABLED in the driver.

John Ogness