[6/9] ipmi: Convert from tasklet to BH workqueue

Message ID 20240327160314.9982-7-apais@linux.microsoft.com (mailing list archive)
State Not Applicable
Headers
Series Convert Tasklets to BH Workqueues |

Commit Message

Allen Pais March 27, 2024, 4:03 p.m. UTC
  The only generic interface to execute asynchronously in the BH context is
tasklet; however, it's marked deprecated and has some design flaws. To
replace tasklets, BH workqueue support was recently added. A BH workqueue
behaves similarly to regular workqueues except that the queued work items
are executed in the BH context.

This patch converts drivers/infiniband/* from tasklet to BH workqueue.

Based on the work done by Tejun Heo <tj@kernel.org>
Branch: https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-6.10

Signed-off-by: Allen Pais <allen.lkml@gmail.com>
---
 drivers/char/ipmi/ipmi_msghandler.c | 30 ++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)
  

Comments

Corey Minyard March 27, 2024, 5:58 p.m. UTC | #1
On Wed, Mar 27, 2024 at 04:03:11PM +0000, Allen Pais wrote:
> The only generic interface to execute asynchronously in the BH context is
> tasklet; however, it's marked deprecated and has some design flaws. To
> replace tasklets, BH workqueue support was recently added. A BH workqueue
> behaves similarly to regular workqueues except that the queued work items
> are executed in the BH context.
> 
> This patch converts drivers/infiniband/* from tasklet to BH workqueue.

I think you mean drivers/char/ipmi/* here.

I believe that work queues items are execute single-threaded for a work
queue, so this should be good.  I need to test this, though.  It may be
that an IPMI device can have its own work queue; it may not be important
to run it in bh context.

-corey

> 
> Based on the work done by Tejun Heo <tj@kernel.org>
> Branch: https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-6.10
> 
> Signed-off-by: Allen Pais <allen.lkml@gmail.com>
> ---
>  drivers/char/ipmi/ipmi_msghandler.c | 30 ++++++++++++++---------------
>  1 file changed, 15 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> index b0eedc4595b3..fce2a2dbdc82 100644
> --- a/drivers/char/ipmi/ipmi_msghandler.c
> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> @@ -36,12 +36,13 @@
>  #include <linux/nospec.h>
>  #include <linux/vmalloc.h>
>  #include <linux/delay.h>
> +#include <linux/workqueue.h>
>  
>  #define IPMI_DRIVER_VERSION "39.2"
>  
>  static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void);
>  static int ipmi_init_msghandler(void);
> -static void smi_recv_tasklet(struct tasklet_struct *t);
> +static void smi_recv_work(struct work_struct *t);
>  static void handle_new_recv_msgs(struct ipmi_smi *intf);
>  static void need_waiter(struct ipmi_smi *intf);
>  static int handle_one_recv_msg(struct ipmi_smi *intf,
> @@ -498,13 +499,13 @@ struct ipmi_smi {
>  	/*
>  	 * Messages queued for delivery.  If delivery fails (out of memory
>  	 * for instance), They will stay in here to be processed later in a
> -	 * periodic timer interrupt.  The tasklet is for handling received
> +	 * periodic timer interrupt.  The work is for handling received
>  	 * messages directly from the handler.
>  	 */
>  	spinlock_t       waiting_rcv_msgs_lock;
>  	struct list_head waiting_rcv_msgs;
>  	atomic_t	 watchdog_pretimeouts_to_deliver;
> -	struct tasklet_struct recv_tasklet;
> +	struct work_struct recv_work;
>  
>  	spinlock_t             xmit_msgs_lock;
>  	struct list_head       xmit_msgs;
> @@ -704,7 +705,7 @@ static void clean_up_interface_data(struct ipmi_smi *intf)
>  	struct cmd_rcvr  *rcvr, *rcvr2;
>  	struct list_head list;
>  
> -	tasklet_kill(&intf->recv_tasklet);
> +	cancel_work_sync(&intf->recv_work);
>  
>  	free_smi_msg_list(&intf->waiting_rcv_msgs);
>  	free_recv_msg_list(&intf->waiting_events);
> @@ -1319,7 +1320,7 @@ static void free_user(struct kref *ref)
>  {
>  	struct ipmi_user *user = container_of(ref, struct ipmi_user, refcount);
>  
> -	/* SRCU cleanup must happen in task context. */
> +	/* SRCU cleanup must happen in work context. */
>  	queue_work(remove_work_wq, &user->remove_work);
>  }
>  
> @@ -3605,8 +3606,7 @@ int ipmi_add_smi(struct module         *owner,
>  	intf->curr_seq = 0;
>  	spin_lock_init(&intf->waiting_rcv_msgs_lock);
>  	INIT_LIST_HEAD(&intf->waiting_rcv_msgs);
> -	tasklet_setup(&intf->recv_tasklet,
> -		     smi_recv_tasklet);
> +	INIT_WORK(&intf->recv_work, smi_recv_work);
>  	atomic_set(&intf->watchdog_pretimeouts_to_deliver, 0);
>  	spin_lock_init(&intf->xmit_msgs_lock);
>  	INIT_LIST_HEAD(&intf->xmit_msgs);
> @@ -4779,7 +4779,7 @@ static void handle_new_recv_msgs(struct ipmi_smi *intf)
>  			 * To preserve message order, quit if we
>  			 * can't handle a message.  Add the message
>  			 * back at the head, this is safe because this
> -			 * tasklet is the only thing that pulls the
> +			 * work is the only thing that pulls the
>  			 * messages.
>  			 */
>  			list_add(&smi_msg->link, &intf->waiting_rcv_msgs);
> @@ -4812,10 +4812,10 @@ static void handle_new_recv_msgs(struct ipmi_smi *intf)
>  	}
>  }
>  
> -static void smi_recv_tasklet(struct tasklet_struct *t)
> +static void smi_recv_work(struct work_struct *t)
>  {
>  	unsigned long flags = 0; /* keep us warning-free. */
> -	struct ipmi_smi *intf = from_tasklet(intf, t, recv_tasklet);
> +	struct ipmi_smi *intf = from_work(intf, t, recv_work);
>  	int run_to_completion = intf->run_to_completion;
>  	struct ipmi_smi_msg *newmsg = NULL;
>  
> @@ -4866,7 +4866,7 @@ void ipmi_smi_msg_received(struct ipmi_smi *intf,
>  
>  	/*
>  	 * To preserve message order, we keep a queue and deliver from
> -	 * a tasklet.
> +	 * a work.
>  	 */
>  	if (!run_to_completion)
>  		spin_lock_irqsave(&intf->waiting_rcv_msgs_lock, flags);
> @@ -4887,9 +4887,9 @@ void ipmi_smi_msg_received(struct ipmi_smi *intf,
>  		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
>  
>  	if (run_to_completion)
> -		smi_recv_tasklet(&intf->recv_tasklet);
> +		smi_recv_work(&intf->recv_work);
>  	else
> -		tasklet_schedule(&intf->recv_tasklet);
> +		queue_work(system_bh_wq, &intf->recv_work);
>  }
>  EXPORT_SYMBOL(ipmi_smi_msg_received);
>  
> @@ -4899,7 +4899,7 @@ void ipmi_smi_watchdog_pretimeout(struct ipmi_smi *intf)
>  		return;
>  
>  	atomic_set(&intf->watchdog_pretimeouts_to_deliver, 1);
> -	tasklet_schedule(&intf->recv_tasklet);
> +	queue_work(system_bh_wq, &intf->recv_work);
>  }
>  EXPORT_SYMBOL(ipmi_smi_watchdog_pretimeout);
>  
> @@ -5068,7 +5068,7 @@ static bool ipmi_timeout_handler(struct ipmi_smi *intf,
>  				       flags);
>  	}
>  
> -	tasklet_schedule(&intf->recv_tasklet);
> +	queue_work(system_bh_wq, &intf->recv_work);
>  
>  	return need_timer;
>  }
> -- 
> 2.17.1
> 
>
  
Allen Pais March 28, 2024, 5:52 p.m. UTC | #2
On Wed, Mar 27, 2024 at 11:05 AM Corey Minyard <minyard@acm.org> wrote:
>
> On Wed, Mar 27, 2024 at 04:03:11PM +0000, Allen Pais wrote:
> > The only generic interface to execute asynchronously in the BH context is
> > tasklet; however, it's marked deprecated and has some design flaws. To
> > replace tasklets, BH workqueue support was recently added. A BH workqueue
> > behaves similarly to regular workqueues except that the queued work items
> > are executed in the BH context.
> >
> > This patch converts drivers/infiniband/* from tasklet to BH workqueue.
>
> I think you mean drivers/char/ipmi/* here.

 My apologies, my scripts messed up the commit messages for this series.
Will have it fixed in v2.

>
> I believe that work queues items are execute single-threaded for a work
> queue, so this should be good.  I need to test this, though.  It may be
> that an IPMI device can have its own work queue; it may not be important
> to run it in bh context.

  Fair point. Could you please let me know once you have had a chance to test
these changes. Meanwhile, I will work on RFC wherein IPMI will have its own
workqueue.

 Thanks for taking time out to review.

- Allen

>
> -corey
>
> >
> > Based on the work done by Tejun Heo <tj@kernel.org>
> > Branch: https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-6.10
> >
> > Signed-off-by: Allen Pais <allen.lkml@gmail.com>
> > ---
> >  drivers/char/ipmi/ipmi_msghandler.c | 30 ++++++++++++++---------------
> >  1 file changed, 15 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> > index b0eedc4595b3..fce2a2dbdc82 100644
> > --- a/drivers/char/ipmi/ipmi_msghandler.c
> > +++ b/drivers/char/ipmi/ipmi_msghandler.c
> > @@ -36,12 +36,13 @@
> >  #include <linux/nospec.h>
> >  #include <linux/vmalloc.h>
> >  #include <linux/delay.h>
> > +#include <linux/workqueue.h>
> >
> >  #define IPMI_DRIVER_VERSION "39.2"
> >
> >  static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void);
> >  static int ipmi_init_msghandler(void);
> > -static void smi_recv_tasklet(struct tasklet_struct *t);
> > +static void smi_recv_work(struct work_struct *t);
> >  static void handle_new_recv_msgs(struct ipmi_smi *intf);
> >  static void need_waiter(struct ipmi_smi *intf);
> >  static int handle_one_recv_msg(struct ipmi_smi *intf,
> > @@ -498,13 +499,13 @@ struct ipmi_smi {
> >       /*
> >        * Messages queued for delivery.  If delivery fails (out of memory
> >        * for instance), They will stay in here to be processed later in a
> > -      * periodic timer interrupt.  The tasklet is for handling received
> > +      * periodic timer interrupt.  The work is for handling received
> >        * messages directly from the handler.
> >        */
> >       spinlock_t       waiting_rcv_msgs_lock;
> >       struct list_head waiting_rcv_msgs;
> >       atomic_t         watchdog_pretimeouts_to_deliver;
> > -     struct tasklet_struct recv_tasklet;
> > +     struct work_struct recv_work;
> >
> >       spinlock_t             xmit_msgs_lock;
> >       struct list_head       xmit_msgs;
> > @@ -704,7 +705,7 @@ static void clean_up_interface_data(struct ipmi_smi *intf)
> >       struct cmd_rcvr  *rcvr, *rcvr2;
> >       struct list_head list;
> >
> > -     tasklet_kill(&intf->recv_tasklet);
> > +     cancel_work_sync(&intf->recv_work);
> >
> >       free_smi_msg_list(&intf->waiting_rcv_msgs);
> >       free_recv_msg_list(&intf->waiting_events);
> > @@ -1319,7 +1320,7 @@ static void free_user(struct kref *ref)
> >  {
> >       struct ipmi_user *user = container_of(ref, struct ipmi_user, refcount);
> >
> > -     /* SRCU cleanup must happen in task context. */
> > +     /* SRCU cleanup must happen in work context. */
> >       queue_work(remove_work_wq, &user->remove_work);
> >  }
> >
> > @@ -3605,8 +3606,7 @@ int ipmi_add_smi(struct module         *owner,
> >       intf->curr_seq = 0;
> >       spin_lock_init(&intf->waiting_rcv_msgs_lock);
> >       INIT_LIST_HEAD(&intf->waiting_rcv_msgs);
> > -     tasklet_setup(&intf->recv_tasklet,
> > -                  smi_recv_tasklet);
> > +     INIT_WORK(&intf->recv_work, smi_recv_work);
> >       atomic_set(&intf->watchdog_pretimeouts_to_deliver, 0);
> >       spin_lock_init(&intf->xmit_msgs_lock);
> >       INIT_LIST_HEAD(&intf->xmit_msgs);
> > @@ -4779,7 +4779,7 @@ static void handle_new_recv_msgs(struct ipmi_smi *intf)
> >                        * To preserve message order, quit if we
> >                        * can't handle a message.  Add the message
> >                        * back at the head, this is safe because this
> > -                      * tasklet is the only thing that pulls the
> > +                      * work is the only thing that pulls the
> >                        * messages.
> >                        */
> >                       list_add(&smi_msg->link, &intf->waiting_rcv_msgs);
> > @@ -4812,10 +4812,10 @@ static void handle_new_recv_msgs(struct ipmi_smi *intf)
> >       }
> >  }
> >
> > -static void smi_recv_tasklet(struct tasklet_struct *t)
> > +static void smi_recv_work(struct work_struct *t)
> >  {
> >       unsigned long flags = 0; /* keep us warning-free. */
> > -     struct ipmi_smi *intf = from_tasklet(intf, t, recv_tasklet);
> > +     struct ipmi_smi *intf = from_work(intf, t, recv_work);
> >       int run_to_completion = intf->run_to_completion;
> >       struct ipmi_smi_msg *newmsg = NULL;
> >
> > @@ -4866,7 +4866,7 @@ void ipmi_smi_msg_received(struct ipmi_smi *intf,
> >
> >       /*
> >        * To preserve message order, we keep a queue and deliver from
> > -      * a tasklet.
> > +      * a work.
> >        */
> >       if (!run_to_completion)
> >               spin_lock_irqsave(&intf->waiting_rcv_msgs_lock, flags);
> > @@ -4887,9 +4887,9 @@ void ipmi_smi_msg_received(struct ipmi_smi *intf,
> >               spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
> >
> >       if (run_to_completion)
> > -             smi_recv_tasklet(&intf->recv_tasklet);
> > +             smi_recv_work(&intf->recv_work);
> >       else
> > -             tasklet_schedule(&intf->recv_tasklet);
> > +             queue_work(system_bh_wq, &intf->recv_work);
> >  }
> >  EXPORT_SYMBOL(ipmi_smi_msg_received);
> >
> > @@ -4899,7 +4899,7 @@ void ipmi_smi_watchdog_pretimeout(struct ipmi_smi *intf)
> >               return;
> >
> >       atomic_set(&intf->watchdog_pretimeouts_to_deliver, 1);
> > -     tasklet_schedule(&intf->recv_tasklet);
> > +     queue_work(system_bh_wq, &intf->recv_work);
> >  }
> >  EXPORT_SYMBOL(ipmi_smi_watchdog_pretimeout);
> >
> > @@ -5068,7 +5068,7 @@ static bool ipmi_timeout_handler(struct ipmi_smi *intf,
> >                                      flags);
> >       }
> >
> > -     tasklet_schedule(&intf->recv_tasklet);
> > +     queue_work(system_bh_wq, &intf->recv_work);
> >
> >       return need_timer;
> >  }
> > --
> > 2.17.1
> >
> >
>
  
Corey Minyard March 28, 2024, 7:23 p.m. UTC | #3
On Thu, Mar 28, 2024 at 10:52:16AM -0700, Allen wrote:
> On Wed, Mar 27, 2024 at 11:05 AM Corey Minyard <minyard@acm.org> wrote:
> >
> > I believe that work queues items are execute single-threaded for a work
> > queue, so this should be good.  I need to test this, though.  It may be
> > that an IPMI device can have its own work queue; it may not be important
> > to run it in bh context.
> 
>   Fair point. Could you please let me know once you have had a chance to test
> these changes. Meanwhile, I will work on RFC wherein IPMI will have its own
> workqueue.
> 
>  Thanks for taking time out to review.

After looking and thinking about it a bit, a BH context is still
probably the best for this.

I have tested this patch under load and various scenarios and it seems
to work ok.  So:

Tested-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Corey Minyard <cminyard@mvista.com>

Or I can take this into my tree.

-corey

> 
> - Allen
> 
> >
> > -corey
> >
> > >
> > > Based on the work done by Tejun Heo <tj@kernel.org>
> > > Branch: https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-610
> > >
> > > Signed-off-by: Allen Pais <allen.lkml@gmail.com>
> > > ---
> > >  drivers/char/ipmi/ipmi_msghandler.c | 30 ++++++++++++++---------------
> > >  1 file changed, 15 insertions(+), 15 deletions(-)
> > >
> > > diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> > > index b0eedc4595b3..fce2a2dbdc82 100644
> > > --- a/drivers/char/ipmi/ipmi_msghandler.c
> > > +++ b/drivers/char/ipmi/ipmi_msghandler.c
> > > @@ -36,12 +36,13 @@
> > >  #include <linux/nospec.h>
> > >  #include <linux/vmalloc.h>
> > >  #include <linux/delay.h>
> > > +#include <linux/workqueue.h>
> > >
> > >  #define IPMI_DRIVER_VERSION "39.2"
> > >
> > >  static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void);
> > >  static int ipmi_init_msghandler(void);
> > > -static void smi_recv_tasklet(struct tasklet_struct *t);
> > > +static void smi_recv_work(struct work_struct *t);
> > >  static void handle_new_recv_msgs(struct ipmi_smi *intf);
> > >  static void need_waiter(struct ipmi_smi *intf);
> > >  static int handle_one_recv_msg(struct ipmi_smi *intf,
> > > @@ -498,13 +499,13 @@ struct ipmi_smi {
> > >       /*
> > >        * Messages queued for delivery.  If delivery fails (out of memory
> > >        * for instance), They will stay in here to be processed later in a
> > > -      * periodic timer interrupt.  The tasklet is for handling received
> > > +      * periodic timer interrupt.  The work is for handling received
> > >        * messages directly from the handler.
> > >        */
> > >       spinlock_t       waiting_rcv_msgs_lock;
> > >       struct list_head waiting_rcv_msgs;
> > >       atomic_t         watchdog_pretimeouts_to_deliver;
> > > -     struct tasklet_struct recv_tasklet;
> > > +     struct work_struct recv_work;
> > >
> > >       spinlock_t             xmit_msgs_lock;
> > >       struct list_head       xmit_msgs;
> > > @@ -704,7 +705,7 @@ static void clean_up_interface_data(struct ipmi_smi *intf)
> > >       struct cmd_rcvr  *rcvr, *rcvr2;
> > >       struct list_head list;
> > >
> > > -     tasklet_kill(&intf->recv_tasklet);
> > > +     cancel_work_sync(&intf->recv_work);
> > >
> > >       free_smi_msg_list(&intf->waiting_rcv_msgs);
> > >       free_recv_msg_list(&intf->waiting_events);
> > > @@ -1319,7 +1320,7 @@ static void free_user(struct kref *ref)
> > >  {
> > >       struct ipmi_user *user = container_of(ref, struct ipmi_user, refcount);
> > >
> > > -     /* SRCU cleanup must happen in task context. */
> > > +     /* SRCU cleanup must happen in work context. */
> > >       queue_work(remove_work_wq, &user->remove_work);
> > >  }
> > >
> > > @@ -3605,8 +3606,7 @@ int ipmi_add_smi(struct module         *owner,
> > >       intf->curr_seq = 0;
> > >       spin_lock_init(&intf->waiting_rcv_msgs_lock);
> > >       INIT_LIST_HEAD(&intf->waiting_rcv_msgs);
> > > -     tasklet_setup(&intf->recv_tasklet,
> > > -                  smi_recv_tasklet);
> > > +     INIT_WORK(&intf->recv_work, smi_recv_work);
> > >       atomic_set(&intf->watchdog_pretimeouts_to_deliver, 0);
> > >       spin_lock_init(&intf->xmit_msgs_lock);
> > >       INIT_LIST_HEAD(&intf->xmit_msgs);
> > > @@ -4779,7 +4779,7 @@ static void handle_new_recv_msgs(struct ipmi_smi *intf)
> > >                        * To preserve message order, quit if we
> > >                        * can't handle a message.  Add the message
> > >                        * back at the head, this is safe because this
> > > -                      * tasklet is the only thing that pulls the
> > > +                      * work is the only thing that pulls the
> > >                        * messages.
> > >                        */
> > >                       list_add(&smi_msg->link, &intf->waiting_rcv_msgs);
> > > @@ -4812,10 +4812,10 @@ static void handle_new_recv_msgs(struct ipmi_smi *intf)
> > >       }
> > >  }
> > >
> > > -static void smi_recv_tasklet(struct tasklet_struct *t)
> > > +static void smi_recv_work(struct work_struct *t)
> > >  {
> > >       unsigned long flags = 0; /* keep us warning-free. */
> > > -     struct ipmi_smi *intf = from_tasklet(intf, t, recv_tasklet);
> > > +     struct ipmi_smi *intf = from_work(intf, t, recv_work);
> > >       int run_to_completion = intf->run_to_completion;
> > >       struct ipmi_smi_msg *newmsg = NULL;
> > >
> > > @@ -4866,7 +4866,7 @@ void ipmi_smi_msg_received(struct ipmi_smi *intf,
> > >
> > >       /*
> > >        * To preserve message order, we keep a queue and deliver from
> > > -      * a tasklet.
> > > +      * a work.
> > >        */
> > >       if (!run_to_completion)
> > >               spin_lock_irqsave(&intf->waiting_rcv_msgs_lock, flags);
> > > @@ -4887,9 +4887,9 @@ void ipmi_smi_msg_received(struct ipmi_smi *intf,
> > >               spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
> > >
> > >       if (run_to_completion)
> > > -             smi_recv_tasklet(&intf->recv_tasklet);
> > > +             smi_recv_work(&intf->recv_work);
> > >       else
> > > -             tasklet_schedule(&intf->recv_tasklet);
> > > +             queue_work(system_bh_wq, &intf->recv_work);
> > >  }
> > >  EXPORT_SYMBOL(ipmi_smi_msg_received);
> > >
> > > @@ -4899,7 +4899,7 @@ void ipmi_smi_watchdog_pretimeout(struct ipmi_smi *intf)
> > >               return;
> > >
> > >       atomic_set(&intf->watchdog_pretimeouts_to_deliver, 1);
> > > -     tasklet_schedule(&intf->recv_tasklet);
> > > +     queue_work(system_bh_wq, &intf->recv_work);
> > >  }
> > >  EXPORT_SYMBOL(ipmi_smi_watchdog_pretimeout);
> > >
> > > @@ -5068,7 +5068,7 @@ static bool ipmi_timeout_handler(struct ipmi_smi *intf,
> > >                                      flags);
> > >       }
> > >
> > > -     tasklet_schedule(&intf->recv_tasklet);
> > > +     queue_work(system_bh_wq, &intf->recv_work);
> > >
> > >       return need_timer;
> > >  }
> > > --
> > > 2.17.1
> > >
> > >
> >
> 
> 
> -- 
>        - Allen
>
  
Allen Pais March 28, 2024, 7:41 p.m. UTC | #4
> > > I believe that work queues items are execute single-threaded for a work
> > > queue, so this should be good.  I need to test this, though.  It may be
> > > that an IPMI device can have its own work queue; it may not be important
> > > to run it in bh context.
> >
> >   Fair point. Could you please let me know once you have had a chance to test
> > these changes. Meanwhile, I will work on RFC wherein IPMI will have its own
> > workqueue.
> >
> >  Thanks for taking time out to review.
>
> After looking and thinking about it a bit, a BH context is still
> probably the best for this.
>
> I have tested this patch under load and various scenarios and it seems
> to work ok.  So:
>
> Tested-by: Corey Minyard <cminyard@mvista.com>
> Acked-by: Corey Minyard <cminyard@mvista.com>
>
> Or I can take this into my tree.
>
> -corey

 Thank you very much. I think it should be okay for you to carry it into
your tree.

- Allen
  
Corey Minyard March 28, 2024, 7:52 p.m. UTC | #5
On Thu, Mar 28, 2024 at 12:41:22PM -0700, Allen wrote:
> > > > I believe that work queues items are execute single-threaded for a work
> > > > queue, so this should be good.  I need to test this, though.  It may be
> > > > that an IPMI device can have its own work queue; it may not be important
> > > > to run it in bh context.
> > >
> > >   Fair point. Could you please let me know once you have had a chance to test
> > > these changes. Meanwhile, I will work on RFC wherein IPMI will have its own
> > > workqueue.
> > >
> > >  Thanks for taking time out to review.
> >
> > After looking and thinking about it a bit, a BH context is still
> > probably the best for this.
> >
> > I have tested this patch under load and various scenarios and it seems
> > to work ok.  So:
> >
> > Tested-by: Corey Minyard <cminyard@mvista.com>
> > Acked-by: Corey Minyard <cminyard@mvista.com>
> >
> > Or I can take this into my tree.
> >
> > -corey
> 
>  Thank you very much. I think it should be okay for you to carry it into
> your tree.

Ok, it's in my for-next tree.  I fixed the directory reference, and I
changed all the comments where you changed "tasklet" to "work" to
instead say "workqueue".

-corey

> 
> - Allen
>
  
Allen Pais March 28, 2024, 7:58 p.m. UTC | #6
> > > >
> > > >   Fair point. Could you please let me know once you have had a chance to test
> > > > these changes. Meanwhile, I will work on RFC wherein IPMI will have its own
> > > > workqueue.
> > > >
> > > >  Thanks for taking time out to review.
> > >
> > > After looking and thinking about it a bit, a BH context is still
> > > probably the best for this.
> > >
> > > I have tested this patch under load and various scenarios and it seems
> > > to work ok.  So:
> > >
> > > Tested-by: Corey Minyard <cminyard@mvista.com>
> > > Acked-by: Corey Minyard <cminyard@mvista.com>
> > >
> > > Or I can take this into my tree.
> > >
> > > -corey
> >
> >  Thank you very much. I think it should be okay for you to carry it into
> > your tree.
>
> Ok, it's in my for-next tree.  I fixed the directory reference, and I
> changed all the comments where you changed "tasklet" to "work" to
> instead say "workqueue".
>

 Thank you very much for fixing it.

- Allen
  

Patch

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index b0eedc4595b3..fce2a2dbdc82 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -36,12 +36,13 @@ 
 #include <linux/nospec.h>
 #include <linux/vmalloc.h>
 #include <linux/delay.h>
+#include <linux/workqueue.h>
 
 #define IPMI_DRIVER_VERSION "39.2"
 
 static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void);
 static int ipmi_init_msghandler(void);
-static void smi_recv_tasklet(struct tasklet_struct *t);
+static void smi_recv_work(struct work_struct *t);
 static void handle_new_recv_msgs(struct ipmi_smi *intf);
 static void need_waiter(struct ipmi_smi *intf);
 static int handle_one_recv_msg(struct ipmi_smi *intf,
@@ -498,13 +499,13 @@  struct ipmi_smi {
 	/*
 	 * Messages queued for delivery.  If delivery fails (out of memory
 	 * for instance), They will stay in here to be processed later in a
-	 * periodic timer interrupt.  The tasklet is for handling received
+	 * periodic timer interrupt.  The work is for handling received
 	 * messages directly from the handler.
 	 */
 	spinlock_t       waiting_rcv_msgs_lock;
 	struct list_head waiting_rcv_msgs;
 	atomic_t	 watchdog_pretimeouts_to_deliver;
-	struct tasklet_struct recv_tasklet;
+	struct work_struct recv_work;
 
 	spinlock_t             xmit_msgs_lock;
 	struct list_head       xmit_msgs;
@@ -704,7 +705,7 @@  static void clean_up_interface_data(struct ipmi_smi *intf)
 	struct cmd_rcvr  *rcvr, *rcvr2;
 	struct list_head list;
 
-	tasklet_kill(&intf->recv_tasklet);
+	cancel_work_sync(&intf->recv_work);
 
 	free_smi_msg_list(&intf->waiting_rcv_msgs);
 	free_recv_msg_list(&intf->waiting_events);
@@ -1319,7 +1320,7 @@  static void free_user(struct kref *ref)
 {
 	struct ipmi_user *user = container_of(ref, struct ipmi_user, refcount);
 
-	/* SRCU cleanup must happen in task context. */
+	/* SRCU cleanup must happen in work context. */
 	queue_work(remove_work_wq, &user->remove_work);
 }
 
@@ -3605,8 +3606,7 @@  int ipmi_add_smi(struct module         *owner,
 	intf->curr_seq = 0;
 	spin_lock_init(&intf->waiting_rcv_msgs_lock);
 	INIT_LIST_HEAD(&intf->waiting_rcv_msgs);
-	tasklet_setup(&intf->recv_tasklet,
-		     smi_recv_tasklet);
+	INIT_WORK(&intf->recv_work, smi_recv_work);
 	atomic_set(&intf->watchdog_pretimeouts_to_deliver, 0);
 	spin_lock_init(&intf->xmit_msgs_lock);
 	INIT_LIST_HEAD(&intf->xmit_msgs);
@@ -4779,7 +4779,7 @@  static void handle_new_recv_msgs(struct ipmi_smi *intf)
 			 * To preserve message order, quit if we
 			 * can't handle a message.  Add the message
 			 * back at the head, this is safe because this
-			 * tasklet is the only thing that pulls the
+			 * work is the only thing that pulls the
 			 * messages.
 			 */
 			list_add(&smi_msg->link, &intf->waiting_rcv_msgs);
@@ -4812,10 +4812,10 @@  static void handle_new_recv_msgs(struct ipmi_smi *intf)
 	}
 }
 
-static void smi_recv_tasklet(struct tasklet_struct *t)
+static void smi_recv_work(struct work_struct *t)
 {
 	unsigned long flags = 0; /* keep us warning-free. */
-	struct ipmi_smi *intf = from_tasklet(intf, t, recv_tasklet);
+	struct ipmi_smi *intf = from_work(intf, t, recv_work);
 	int run_to_completion = intf->run_to_completion;
 	struct ipmi_smi_msg *newmsg = NULL;
 
@@ -4866,7 +4866,7 @@  void ipmi_smi_msg_received(struct ipmi_smi *intf,
 
 	/*
 	 * To preserve message order, we keep a queue and deliver from
-	 * a tasklet.
+	 * a work.
 	 */
 	if (!run_to_completion)
 		spin_lock_irqsave(&intf->waiting_rcv_msgs_lock, flags);
@@ -4887,9 +4887,9 @@  void ipmi_smi_msg_received(struct ipmi_smi *intf,
 		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
 
 	if (run_to_completion)
-		smi_recv_tasklet(&intf->recv_tasklet);
+		smi_recv_work(&intf->recv_work);
 	else
-		tasklet_schedule(&intf->recv_tasklet);
+		queue_work(system_bh_wq, &intf->recv_work);
 }
 EXPORT_SYMBOL(ipmi_smi_msg_received);
 
@@ -4899,7 +4899,7 @@  void ipmi_smi_watchdog_pretimeout(struct ipmi_smi *intf)
 		return;
 
 	atomic_set(&intf->watchdog_pretimeouts_to_deliver, 1);
-	tasklet_schedule(&intf->recv_tasklet);
+	queue_work(system_bh_wq, &intf->recv_work);
 }
 EXPORT_SYMBOL(ipmi_smi_watchdog_pretimeout);
 
@@ -5068,7 +5068,7 @@  static bool ipmi_timeout_handler(struct ipmi_smi *intf,
 				       flags);
 	}
 
-	tasklet_schedule(&intf->recv_tasklet);
+	queue_work(system_bh_wq, &intf->recv_work);
 
 	return need_timer;
 }