diff mbox series

[2/5] firewire: core: add local API to queue work item to workqueue specific to isochronous contexts

Message ID 20240904125155.461886-3-o-takashi@sakamocchi.jp (mailing list archive)
State New
Headers
Series firewire: use sleepable workqueue to handle 1394 OHCI IT/IR context events |

Checks

Context Check Description
media-ci/media-ci fail Failed to cherry-pick patch on top of media-staging

Commit Message

Takashi Sakamoto Sept. 4, 2024, 12:51 p.m. UTC 
  In the previous commit, the workqueue is added per the instance of fw_card
structure for isochronous contexts. The workqueue is designed to be used by
the implementation of fw_card_driver structure underlying the fw_card.

This commit adds some local APIs to be used by the implementation.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
---
 drivers/firewire/core-iso.c | 30 ++++++++++++++++++++++++++++--
 drivers/firewire/core.h     | 10 ++++++++++
 include/linux/firewire.h    |  1 +
 3 files changed, 39 insertions(+), 2 deletions(-)

Comments

Takashi Iwai Sept. 4, 2024, 4:07 p.m. UTC | #1 
On Wed, 04 Sep 2024 14:51:51 +0200,
Takashi Sakamoto wrote:
> 
> In the previous commit, the workqueue is added per the instance of fw_card
> structure for isochronous contexts. The workqueue is designed to be used by
> the implementation of fw_card_driver structure underlying the fw_card.
> 
> This commit adds some local APIs to be used by the implementation.
> 
> Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
> ---
>  drivers/firewire/core-iso.c | 30 ++++++++++++++++++++++++++++--
>  drivers/firewire/core.h     | 10 ++++++++++
>  include/linux/firewire.h    |  1 +
>  3 files changed, 39 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/firewire/core-iso.c b/drivers/firewire/core-iso.c
> index 101433b8bb51..af76fa1823f1 100644
> --- a/drivers/firewire/core-iso.c
> +++ b/drivers/firewire/core-iso.c
> @@ -211,21 +211,47 @@ EXPORT_SYMBOL(fw_iso_context_queue_flush);
>  
>  int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
>  {
> +	int err;
> +
>  	trace_isoc_outbound_flush_completions(ctx);
>  	trace_isoc_inbound_single_flush_completions(ctx);
>  	trace_isoc_inbound_multiple_flush_completions(ctx);
>  
> -	return ctx->card->driver->flush_iso_completions(ctx);
> +	might_sleep();
> +
> +	// Avoid dead lock due to programming mistake.
> +	if (WARN_ON(current_work() == &ctx->work))
> +		return 0;

Maybe WARN_ON_ONCE() would be safer if it's supposed to be called
frequently.  Otherwise it can spam too much.
Ditto for fw_iso_context_stop().


thanks,

Takashi
Takashi Sakamoto Sept. 5, 2024, 8:07 a.m. UTC | #2 
Hi,

On Wed, Sep 04, 2024 at 06:07:20PM +0200, Takashi Iwai wrote:
> On Wed, 04 Sep 2024 14:51:51 +0200,
> Takashi Sakamoto wrote:
> > 
> > In the previous commit, the workqueue is added per the instance of fw_card
> > structure for isochronous contexts. The workqueue is designed to be used by
> > the implementation of fw_card_driver structure underlying the fw_card.
> > 
> > This commit adds some local APIs to be used by the implementation.
> > 
> > Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
> > ---
> >  drivers/firewire/core-iso.c | 30 ++++++++++++++++++++++++++++--
> >  drivers/firewire/core.h     | 10 ++++++++++
> >  include/linux/firewire.h    |  1 +
> >  3 files changed, 39 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/firewire/core-iso.c b/drivers/firewire/core-iso.c
> > index 101433b8bb51..af76fa1823f1 100644
> > --- a/drivers/firewire/core-iso.c
> > +++ b/drivers/firewire/core-iso.c
> > @@ -211,21 +211,47 @@ EXPORT_SYMBOL(fw_iso_context_queue_flush);
> >  
> >  int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
> >  {
> > +	int err;
> > +
> >  	trace_isoc_outbound_flush_completions(ctx);
> >  	trace_isoc_inbound_single_flush_completions(ctx);
> >  	trace_isoc_inbound_multiple_flush_completions(ctx);
> >  
> > -	return ctx->card->driver->flush_iso_completions(ctx);
> > +	might_sleep();
> > +
> > +	// Avoid dead lock due to programming mistake.
> > +	if (WARN_ON(current_work() == &ctx->work))
> > +		return 0;
> 
> Maybe WARN_ON_ONCE() would be safer if it's supposed to be called
> frequently.  Otherwise it can spam too much.
> Ditto for fw_iso_context_stop().

Thanks for your suggestion. Indeed, the kernel API would be called so
frequently, and the *_ONCE macro would be safer. I'll post another patch
for it, since posting updated series of changes to all of receivers is a
bit cumbersome to me...


Thanks

Takashi Sakamoto
diff mbox series

Patch

diff --git a/drivers/firewire/core-iso.c b/drivers/firewire/core-iso.c
index 101433b8bb51..af76fa1823f1 100644
--- a/drivers/firewire/core-iso.c
+++ b/drivers/firewire/core-iso.c
@@ -211,21 +211,47 @@  EXPORT_SYMBOL(fw_iso_context_queue_flush);
 
 int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
 {
+	int err;
+
 	trace_isoc_outbound_flush_completions(ctx);
 	trace_isoc_inbound_single_flush_completions(ctx);
 	trace_isoc_inbound_multiple_flush_completions(ctx);
 
-	return ctx->card->driver->flush_iso_completions(ctx);
+	might_sleep();
+
+	// Avoid dead lock due to programming mistake.
+	if (WARN_ON(current_work() == &ctx->work))
+		return 0;
+
+	disable_work_sync(&ctx->work);
+
+	err = ctx->card->driver->flush_iso_completions(ctx);
+
+	enable_work(&ctx->work);
+
+	return err;
 }
 EXPORT_SYMBOL(fw_iso_context_flush_completions);
 
 int fw_iso_context_stop(struct fw_iso_context *ctx)
 {
+	int err;
+
 	trace_isoc_outbound_stop(ctx);
 	trace_isoc_inbound_single_stop(ctx);
 	trace_isoc_inbound_multiple_stop(ctx);
 
-	return ctx->card->driver->stop_iso(ctx);
+	might_sleep();
+
+	// Avoid dead lock due to programming mistake.
+	if (WARN_ON(current_work() == &ctx->work))
+		return 0;
+
+	err = ctx->card->driver->stop_iso(ctx);
+
+	cancel_work_sync(&ctx->work);
+
+	return err;
 }
 EXPORT_SYMBOL(fw_iso_context_stop);
 
diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index 96ae366889e0..2874f316156a 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -159,6 +159,16 @@  int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count);
 int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
 			  enum dma_data_direction direction);
 
+static inline void fw_iso_context_init_work(struct fw_iso_context *ctx, work_func_t func)
+{
+	INIT_WORK(&ctx->work, func);
+}
+
+static inline void fw_iso_context_queue_work(struct fw_iso_context *ctx)
+{
+	queue_work(ctx->card->isoc_wq, &ctx->work);
+}
+
 
 /* -topology */
 
diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index 10e135d60824..72f497b61739 100644
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -511,6 +511,7 @@  union fw_iso_callback {
 
 struct fw_iso_context {
 	struct fw_card *card;
+	struct work_struct work;
 	int type;
 	int channel;
 	int speed;