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

Allen Pais
2024-03-27T16:03:27Z

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(-)

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