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usb/c67x00: Replace tasklet with work

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Tasklets have long been deprecated as being too heavy on the system
by running in irq context - and this is not a performance critical
path. If a higher priority process wants to run, it must wait for
the tasklet to finish before doing so.

c67x00_do_work() will now run in process context and have further
concurrency (tasklets being serialized among themselves), but this
is done holding the c67x00->lock, so it should be fine. Furthermore,
this patch fixes the usage of the lock in the callback as otherwise
it would need to be irq-safe.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210113031537.79859-1-dave@stgolabs.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Davidlohr Bueso
2021-01-12 19:15:37 -08:00
committed by Greg Kroah-Hartman
parent 7cbcd008e1
commit 60b4c9d5c6
2 changed files with 8 additions and 6 deletions
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2
drivers/usb/c67x00/c67x00-hcd.h
View File

@@ -76,7 +76,7 @@ struct c67x00_hcd {
u16 next_td_addr; u16 next_td_addr;
u16 next_buf_addr; u16 next_buf_addr;
struct tasklet_struct tasklet; struct work_struct work;
struct completion endpoint_disable; struct completion endpoint_disable;

12
drivers/usb/c67x00/c67x00-sched.c
View File

@@ -1123,24 +1123,26 @@ static void c67x00_do_work(struct c67x00_hcd *c67x00)
/* -------------------------------------------------------------------------- */ /* -------------------------------------------------------------------------- */
static void c67x00_sched_tasklet(struct tasklet_struct *t) static void c67x00_sched_work(struct work_struct *work)
{ {
struct c67x00_hcd *c67x00 = from_tasklet(c67x00, t, tasklet); struct c67x00_hcd *c67x00;
c67x00 = container_of(work, struct c67x00_hcd, work);
c67x00_do_work(c67x00); c67x00_do_work(c67x00);
} }
void c67x00_sched_kick(struct c67x00_hcd *c67x00) void c67x00_sched_kick(struct c67x00_hcd *c67x00)
{ {
tasklet_hi_schedule(&c67x00->tasklet); queue_work(system_highpri_wq, &c67x00->work);
} }
int c67x00_sched_start_scheduler(struct c67x00_hcd *c67x00) int c67x00_sched_start_scheduler(struct c67x00_hcd *c67x00)
{ {
tasklet_setup(&c67x00->tasklet, c67x00_sched_tasklet); INIT_WORK(&c67x00->work, c67x00_sched_work);
return 0; return 0;
} }
void c67x00_sched_stop_scheduler(struct c67x00_hcd *c67x00) void c67x00_sched_stop_scheduler(struct c67x00_hcd *c67x00)
{ {
tasklet_kill(&c67x00->tasklet); cancel_work_sync(&c67x00->work);
} }