mirrors/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-04-11 04:50:23 -04:00
Code Issues Packages Projects Releases Wiki Activity

greybus: loopback: convert loopback wake/sleep to a waitqueue

Browse Source 
Current code will incrementally poll for gb->type == 0 and sleep.
This type of polling strategy wastes cycles.

This patch changes the sleep strategy by introducing a wait-queue which
waits for gb->type != 0 or kthread_should_stop() to wake-up and work or
to wake-up and terminate.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Bryan O'Donoghue
2015-07-24 10:02:56 +01:00
committed by Greg Kroah-Hartman
parent c2939f41bc
commit 3dfe8aaaee
1 changed files with 19 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/staging/greybus/loopback.c
View File

@@ -31,6 +31,7 @@ struct gb_loopback {
u8 version_minor;
struct task_struct *task;
wait_queue_head_t wq;
int type;
u32 size;
@@ -113,15 +114,6 @@ static DEVICE_ATTR_RW(field)
static void gb_loopback_reset_stats(struct gb_loopback *gb);
static void gb_loopback_check_attr(struct gb_loopback *gb)
{
switch (gb->type) {
case GB_LOOPBACK_TYPE_PING:
case GB_LOOPBACK_TYPE_TRANSFER:
case GB_LOOPBACK_TYPE_SINK:
break;
default:
gb->type = 0;
break;
}
if (gb->ms_wait > GB_LOOPBACK_MS_WAIT_MAX)
gb->ms_wait = GB_LOOPBACK_MS_WAIT_MAX;
if (gb->size > gb->size_max)
@@ -129,6 +121,17 @@ static void gb_loopback_check_attr(struct gb_loopback *gb)
gb->error = 0;
gb->iteration_count = 0;
gb_loopback_reset_stats(gb);
switch (gb->type) {
case GB_LOOPBACK_TYPE_PING:
case GB_LOOPBACK_TYPE_TRANSFER:
case GB_LOOPBACK_TYPE_SINK:
wake_up(&gb->wq);
break;
default:
gb->type = 0;
break;
}
}
/* Time to send and receive one message */
@@ -397,11 +400,12 @@ static int gb_loopback_fn(void *data)
struct timeval tlat = {0, 0};
struct gb_loopback *gb = (struct gb_loopback *)data;
while (!kthread_should_stop()) {
if (!gb->type) {
msleep(1000);
continue;
}
while (1) {
if (!gb->type)
wait_event_interruptible(gb->wq, gb->type ||
kthread_should_stop());
if (kthread_should_stop())
break;
if (gb->iteration_max) {
if (gb->iteration_count < gb->iteration_max) {
gb->iteration_count++;
@@ -429,7 +433,6 @@ static int gb_loopback_fn(void *data)
gb->ts = gb->te;
if (gb->ms_wait)
msleep(gb->ms_wait);
}
return 0;
}
@@ -463,6 +466,7 @@ static int gb_loopback_connection_init(struct gb_connection *connection)
gb->size_max -= sizeof(struct gb_loopback_transfer_request);
gb_loopback_reset_stats(gb);
init_waitqueue_head(&gb->wq);
gb->task = kthread_run(gb_loopback_fn, gb, "gb_loopback");
if (IS_ERR(gb->task)) {
retval = PTR_ERR(gb->task);