Re: [PATCH 6/9] ipmi: Convert from tasklet to BH workqueue
On Wed, Mar 27, 2024 at 04:03:11PM +, 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
> Branch: https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-6.10
>
> Signed-off-by: Allen Pais
> ---
> 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
> #include
> #include
> +#include
>
> #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)
Re: [PATCH 6/9] ipmi: Convert from tasklet to BH workqueue
On Thu, Mar 28, 2024 at 10:52:16AM -0700, Allen wrote:
> On Wed, Mar 27, 2024 at 11:05 AM Corey Minyard 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
Acked-by: Corey Minyard
Or I can take this into my tree.
-corey
>
> - Allen
>
> >
> > -corey
> >
> > >
> > > Based on the work done by Tejun Heo
> > > Branch: https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-610
> > >
> > > Signed-off-by: Allen Pais
> > > ---
> > > 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
> > > #include
> > > #include
> > > +#include
> > >
> > > #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
Re: [PATCH 6/9] ipmi: Convert from tasklet to BH workqueue
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 > > Acked-by: Corey Minyard > > > > 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 >
Re: [PATCH] treewide: const qualify ctl_tables where applicable
On Thu, Jan 09, 2025 at 02:16:39PM +0100, Joel Granados wrote:
> Add the const qualifier to all the ctl_tables in the tree except the
> ones in ./net dir. The "net" sysctl code is special as it modifies the
> arrays before passing it on to the registration function.
>
...
> diff --git a/drivers/char/ipmi/ipmi_poweroff.c
> b/drivers/char/ipmi/ipmi_poweroff.c
> index 941d2dcc8c9d..de84f59468a9 100644
> --- a/drivers/char/ipmi/ipmi_poweroff.c
> +++ b/drivers/char/ipmi/ipmi_poweroff.c
> @@ -650,7 +650,7 @@ static struct ipmi_smi_watcher smi_watcher = {
> #ifdef CONFIG_PROC_FS
> #include
>
> -static struct ctl_table ipmi_table[] = {
> +static const struct ctl_table ipmi_table[] = {
> { .procname = "poweroff_powercycle",
> .data = &poweroff_powercycle,
> .maxlen = sizeof(poweroff_powercycle),
For the IPMI portion:
Acked-by: Corey Minyard
