* [PATCH] powerpc: eeh_event: convert semaphore to completion
@ 2018-12-10 21:51 Arnd Bergmann
2018-12-10 23:18 ` Oliver
2018-12-22 9:54 ` Michael Ellerman
0 siblings, 2 replies; 4+ messages in thread
From: Arnd Bergmann @ 2018-12-10 21:51 UTC (permalink / raw)
To: Russell Currey, Sam Bobroff, Oliver O'Halloran,
Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
Cc: Alexey Kardashevskiy, linuxppc-dev, linux-kernel, Arnd Bergmann
For this use case, completions and semaphores are equivalent,
but semaphores are an awkward interface that should generally
be avoided, so use the completion instead.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
arch/powerpc/kernel/eeh_event.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/kernel/eeh_event.c b/arch/powerpc/kernel/eeh_event.c
index 61c9356bf9c9..227e57f980df 100644
--- a/arch/powerpc/kernel/eeh_event.c
+++ b/arch/powerpc/kernel/eeh_event.c
@@ -35,7 +35,7 @@
*/
static DEFINE_SPINLOCK(eeh_eventlist_lock);
-static struct semaphore eeh_eventlist_sem;
+static DECLARE_COMPLETION(eeh_eventlist_event);
static LIST_HEAD(eeh_eventlist);
/**
@@ -55,7 +55,7 @@ static int eeh_event_handler(void * dummy)
struct eeh_pe *pe;
while (!kthread_should_stop()) {
- if (down_interruptible(&eeh_eventlist_sem))
+ if (wait_for_completion_interruptible(&eeh_eventlist_event))
break;
/* Fetch EEH event from the queue */
@@ -102,9 +102,6 @@ int eeh_event_init(void)
struct task_struct *t;
int ret = 0;
- /* Initialize semaphore */
- sema_init(&eeh_eventlist_sem, 0);
-
t = kthread_run(eeh_event_handler, NULL, "eehd");
if (IS_ERR(t)) {
ret = PTR_ERR(t);
@@ -142,7 +139,7 @@ int eeh_send_failure_event(struct eeh_pe *pe)
spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
/* For EEH deamon to knick in */
- up(&eeh_eventlist_sem);
+ complete(&eeh_eventlist_event);
return 0;
}
--
2.20.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] powerpc: eeh_event: convert semaphore to completion
2018-12-10 21:51 [PATCH] powerpc: eeh_event: convert semaphore to completion Arnd Bergmann
@ 2018-12-10 23:18 ` Oliver
2018-12-10 23:33 ` Sam Bobroff
2018-12-22 9:54 ` Michael Ellerman
1 sibling, 1 reply; 4+ messages in thread
From: Oliver @ 2018-12-10 23:18 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Sam Bobroff, Linux Kernel Mailing List, aik, Paul Mackerras,
linuxppc-dev
On Tue, Dec 11, 2018 at 8:52 AM Arnd Bergmann <arnd@arndb.de> wrote:
>
> For this use case, completions and semaphores are equivalent,
> but semaphores are an awkward interface that should generally
> be avoided, so use the completion instead.
IIRC Sam has been reworking the locking used inside of EEH so this is
probably going to clash with his changes. Converting to a completion
is probably a good idea, but we might want to do it as a part of his
series since it's going to collide with this anyway.
Sam, what do you think?
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> arch/powerpc/kernel/eeh_event.c | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/kernel/eeh_event.c b/arch/powerpc/kernel/eeh_event.c
> index 61c9356bf9c9..227e57f980df 100644
> --- a/arch/powerpc/kernel/eeh_event.c
> +++ b/arch/powerpc/kernel/eeh_event.c
> @@ -35,7 +35,7 @@
> */
>
> static DEFINE_SPINLOCK(eeh_eventlist_lock);
> -static struct semaphore eeh_eventlist_sem;
> +static DECLARE_COMPLETION(eeh_eventlist_event);
> static LIST_HEAD(eeh_eventlist);
>
> /**
> @@ -55,7 +55,7 @@ static int eeh_event_handler(void * dummy)
> struct eeh_pe *pe;
>
> while (!kthread_should_stop()) {
> - if (down_interruptible(&eeh_eventlist_sem))
> + if (wait_for_completion_interruptible(&eeh_eventlist_event))
> break;
>
> /* Fetch EEH event from the queue */
> @@ -102,9 +102,6 @@ int eeh_event_init(void)
> struct task_struct *t;
> int ret = 0;
>
> - /* Initialize semaphore */
> - sema_init(&eeh_eventlist_sem, 0);
> -
> t = kthread_run(eeh_event_handler, NULL, "eehd");
> if (IS_ERR(t)) {
> ret = PTR_ERR(t);
> @@ -142,7 +139,7 @@ int eeh_send_failure_event(struct eeh_pe *pe)
> spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
>
> /* For EEH deamon to knick in */
> - up(&eeh_eventlist_sem);
> + complete(&eeh_eventlist_event);
>
> return 0;
> }
> --
> 2.20.0
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] powerpc: eeh_event: convert semaphore to completion
2018-12-10 23:18 ` Oliver
@ 2018-12-10 23:33 ` Sam Bobroff
0 siblings, 0 replies; 4+ messages in thread
From: Sam Bobroff @ 2018-12-10 23:33 UTC (permalink / raw)
To: Oliver
Cc: Arnd Bergmann, aik, Linux Kernel Mailing List, Paul Mackerras,
linuxppc-dev
[-- Attachment #1: Type: text/plain, Size: 2508 bytes --]
On Tue, Dec 11, 2018 at 10:18:31AM +1100, Oliver wrote:
> On Tue, Dec 11, 2018 at 8:52 AM Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > For this use case, completions and semaphores are equivalent,
> > but semaphores are an awkward interface that should generally
> > be avoided, so use the completion instead.
>
> IIRC Sam has been reworking the locking used inside of EEH so this is
> probably going to clash with his changes. Converting to a completion
> is probably a good idea, but we might want to do it as a part of his
> series since it's going to collide with this anyway.
>
> Sam, what do you think?
It's such a small change, I don't think it will cause any problems for
the rework. Anyway it seems like a good change, so I'd prefer to see it
go in :-)
Cheers,
Sam.
> >
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > arch/powerpc/kernel/eeh_event.c | 9 +++------
> > 1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/powerpc/kernel/eeh_event.c b/arch/powerpc/kernel/eeh_event.c
> > index 61c9356bf9c9..227e57f980df 100644
> > --- a/arch/powerpc/kernel/eeh_event.c
> > +++ b/arch/powerpc/kernel/eeh_event.c
> > @@ -35,7 +35,7 @@
> > */
> >
> > static DEFINE_SPINLOCK(eeh_eventlist_lock);
> > -static struct semaphore eeh_eventlist_sem;
> > +static DECLARE_COMPLETION(eeh_eventlist_event);
> > static LIST_HEAD(eeh_eventlist);
> >
> > /**
> > @@ -55,7 +55,7 @@ static int eeh_event_handler(void * dummy)
> > struct eeh_pe *pe;
> >
> > while (!kthread_should_stop()) {
> > - if (down_interruptible(&eeh_eventlist_sem))
> > + if (wait_for_completion_interruptible(&eeh_eventlist_event))
> > break;
> >
> > /* Fetch EEH event from the queue */
> > @@ -102,9 +102,6 @@ int eeh_event_init(void)
> > struct task_struct *t;
> > int ret = 0;
> >
> > - /* Initialize semaphore */
> > - sema_init(&eeh_eventlist_sem, 0);
> > -
> > t = kthread_run(eeh_event_handler, NULL, "eehd");
> > if (IS_ERR(t)) {
> > ret = PTR_ERR(t);
> > @@ -142,7 +139,7 @@ int eeh_send_failure_event(struct eeh_pe *pe)
> > spin_unlock_irqrestore(&eeh_eventlist_lock, flags);
> >
> > /* For EEH deamon to knick in */
> > - up(&eeh_eventlist_sem);
> > + complete(&eeh_eventlist_event);
> >
> > return 0;
> > }
> > --
> > 2.20.0
> >
>
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: powerpc: eeh_event: convert semaphore to completion
2018-12-10 21:51 [PATCH] powerpc: eeh_event: convert semaphore to completion Arnd Bergmann
2018-12-10 23:18 ` Oliver
@ 2018-12-22 9:54 ` Michael Ellerman
1 sibling, 0 replies; 4+ messages in thread
From: Michael Ellerman @ 2018-12-22 9:54 UTC (permalink / raw)
To: Arnd Bergmann, Russell Currey, Sam Bobroff,
Oliver O'Halloran, Benjamin Herrenschmidt, Paul Mackerras
Cc: Alexey Kardashevskiy, linuxppc-dev, linux-kernel, Arnd Bergmann
On Mon, 2018-12-10 at 21:51:57 UTC, Arnd Bergmann wrote:
> For this use case, completions and semaphores are equivalent,
> but semaphores are an awkward interface that should generally
> be avoided, so use the completion instead.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/2fea82db113e4422ef5c8e62099088
cheers
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-12-10 23:18 ` Oliver
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2018-12-22 9:54 ` Michael Ellerman
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