The 'registered' flag is internally used by kmsg_dump_register()
and kmsg_dump_unregister() to track multiple registrations of the
same dumper.
It's protected by printk's internal dump_list_lock, and must thus
be accessed only from there. Mark it as private.
Signed-off-by: Ahmed S. Darwish <[email protected]>
---
include/linux/kmsg_dump.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
index 2e7a1e032c71..7c08cb58259a 100644
--- a/include/linux/kmsg_dump.h
+++ b/include/linux/kmsg_dump.h
@@ -36,7 +36,7 @@ enum kmsg_dump_reason {
* @dump: Call into dumping code which will retrieve the data with
* through the record iterator
* @max_reason: filter for highest reason number that should be dumped
- * @registered: Flag that specifies if this is already registered
+ * @registered: Flag that specifies if this is already registered (private)
*/
struct kmsg_dumper {
struct list_head list;
--
2.21.0
On (03/10/19 21:03), Ahmed S. Darwish wrote:
> The 'registered' flag is internally used by kmsg_dump_register()
> and kmsg_dump_unregister() to track multiple registrations of the
> same dumper.
>
> It's protected by printk's internal dump_list_lock, and must thus
> be accessed only from there. Mark it as private.
>
> Signed-off-by: Ahmed S. Darwish <[email protected]>
> ---
> include/linux/kmsg_dump.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
> index 2e7a1e032c71..7c08cb58259a 100644
> --- a/include/linux/kmsg_dump.h
> +++ b/include/linux/kmsg_dump.h
> @@ -36,7 +36,7 @@ enum kmsg_dump_reason {
> * @dump: Call into dumping code which will retrieve the data with
> * through the record iterator
> * @max_reason: filter for highest reason number that should be dumped
> - * @registered: Flag that specifies if this is already registered
> + * @registered: Flag that specifies if this is already registered (private)
> */
> struct kmsg_dumper {
> struct list_head list;
Do we really do this thing?
$ git grep "(private)" include/linux/
include/linux/kmsg_dump.h: * @list: Entry in the dumper list (private)
include/linux/uwb.h: * specific (private) DevAddr (UWB_RSV_TARGET_DEVADDR).
-ss
On Mon 2019-03-11 21:49:05, Sergey Senozhatsky wrote:
> On (03/10/19 21:03), Ahmed S. Darwish wrote:
> > The 'registered' flag is internally used by kmsg_dump_register()
> > and kmsg_dump_unregister() to track multiple registrations of the
> > same dumper.
> >
> > It's protected by printk's internal dump_list_lock, and must thus
> > be accessed only from there. Mark it as private.
> >
> > Signed-off-by: Ahmed S. Darwish <[email protected]>
> > ---
> > include/linux/kmsg_dump.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
> > index 2e7a1e032c71..7c08cb58259a 100644
> > --- a/include/linux/kmsg_dump.h
> > +++ b/include/linux/kmsg_dump.h
> > @@ -36,7 +36,7 @@ enum kmsg_dump_reason {
> > * @dump: Call into dumping code which will retrieve the data with
> > * through the record iterator
> > * @max_reason: filter for highest reason number that should be dumped
> > - * @registered: Flag that specifies if this is already registered
> > + * @registered: Flag that specifies if this is already registered (private)
> > */
> > struct kmsg_dumper {
> > struct list_head list;
>
>
> Do we really do this thing?
Good question.
> $ git grep "(private)" include/linux/
> include/linux/kmsg_dump.h: * @list: Entry in the dumper list (private)
This is another field in the same structure. There are 4 other fields
that are described as private by extra comment. Thefore this patch
might make it more consistent.
Well, I am not sure if it is worth it. Andrew?
> include/linux/uwb.h: * specific (private) DevAddr (UWB_RSV_TARGET_DEVADDR).
Best Regards,
Petr
On (03/12/19 10:18), Petr Mladek wrote:
> > > * @max_reason: filter for highest reason number that should be dumped
> > > - * @registered: Flag that specifies if this is already registered
> > > + * @registered: Flag that specifies if this is already registered (private)
> > > */
> > > struct kmsg_dumper {
> > > struct list_head list;
> >
[..]
> This is another field in the same structure. There are 4 other fields
> that are described as private by extra comment. Thefore this patch
> might make it more consistent.
Well, no objections from my side. At the same time nothing in kmsg_dump.h
suggests that "(private)" stands for "protected by logbuf_lock". Even more,
that struct has another "private" members, which are protected by
logbuf_lock - cur_idx, next_idx, cur_srq, next_seq; except when they are
not (see kmsg_dump_get_line_nolock() and other _nolock() functions). So
"private" has conflicting meanings.
struct kmsg_dumper {
struct list_head list;
void (*dump)(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason);
enum kmsg_dump_reason max_reason;
bool active;
bool registered;
/* private state of the kmsg iterator */
u32 cur_idx;
u32 next_idx;
u64 cur_seq;
u64 next_seq;
};
>
> Well, I am not sure if it is worth it. Andrew?
>
Agreed.
-ss
Hi,
On Mon, Mar 11, 2019 at 09:49:05PM +0900, Sergey Senozhatsky wrote:
> On (03/10/19 21:03), Ahmed S. Darwish wrote:
> > The 'registered' flag is internally used by kmsg_dump_register()
> > and kmsg_dump_unregister() to track multiple registrations of the
> > same dumper.
> >
> > It's protected by printk's internal dump_list_lock, and must thus
> > be accessed only from there. Mark it as private.
> >
> > Signed-off-by: Ahmed S. Darwish <[email protected]>
> > ---
> > include/linux/kmsg_dump.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/linux/kmsg_dump.h b/include/linux/kmsg_dump.h
> > index 2e7a1e032c71..7c08cb58259a 100644
> > --- a/include/linux/kmsg_dump.h
> > +++ b/include/linux/kmsg_dump.h
> > @@ -36,7 +36,7 @@ enum kmsg_dump_reason {
> > * @dump: Call into dumping code which will retrieve the data with
> > * through the record iterator
> > * @max_reason: filter for highest reason number that should be dumped
> > - * @registered: Flag that specifies if this is already registered
> > + * @registered: Flag that specifies if this is already registered (private)
> > */
> > struct kmsg_dumper {
> > struct list_head list;
>
>
> Do we really do this thing?
>
>
> $ git grep "(private)" include/linux/
> include/linux/kmsg_dump.h: * @list: Entry in the dumper list (private)
> include/linux/uwb.h: * specific (private) DevAddr (UWB_RSV_TARGET_DEVADDR).
>
Hmmm, while writing a kmsg_dumper for [1], I noticed that struct
kmsg_dumper is:
/**
* struct kmsg_dumper - kernel crash message dumper structure
* @list: Entry in the dumper list (private) <== *
* ...
* @registered: Flag that specifies if this is already registered
*/
struct kmsg_dumper {
struct list_head list;
...
bool registered;
/* private state of the kmsg iterator */ <== *
...
};
_All_ private members are annotated (<== *), so this gave the
impression that 'bool registered' was public..
Then I discovered from printk.c code that it's actually private,
and protected by the printk's internal dump_list_lock...
So this trivial patch was submitted for consistency.
thanks,
[1] https://lore.kernel.org/lkml/20190310013142.GA3376@darwi-home-pc
--
darwi
http://darwish.chasingpointers.com