drivers/block: replace use of system_wq with system_percpu_wq

Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistentcy cannot be addressed without refactoring the API.

system_unbound_wq should be the default workqueue so as not to enforce
locality constraints for random work whenever it's not required.

Adding system_dfl_wq to encourage its use when unbound work should be used.

queue_work() / queue_delayed_work() / mod_delayed_work() will now use the
new unbound wq: whether the user still use the old wq a warn will be
printed along with a wq redirect to the new one.

The old system_unbound_wq will be kept for a few release cycles.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 87b0b78249da3325023949585f4daf40486c9692..1188f32a5e5ea32ee016f3ae0764d8b3193494c7 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -311,7 +311,7 @@ static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
                if (args) {
                        INIT_WORK(&args->work, nbd_dead_link_work);
                        args->index = nbd->index;
-                       queue_work(system_wq, &args->work);
+                       queue_work(system_percpu_wq, &args->work);
                }
        }
        if (!nsock->dead) {

diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
index 107751721178d7109371615232ba4c8f5b5db054..3ab46bb0c23dbd5bca09b51db4786d68d8d93bb4 100644 (file)
--- a/drivers/block/sunvdc.c
+++ b/drivers/block/sunvdc.c
@@ -1188,7 +1188,7 @@ static void vdc_ldc_reset(struct vdc_port *port)
        }
 
        if (port->ldc_timeout)
-               mod_delayed_work(system_wq, &port->ldc_reset_timer_work,
+               mod_delayed_work(system_percpu_wq, &port->ldc_reset_timer_work,
                          round_jiffies(jiffies + HZ * port->ldc_timeout));
        mod_timer(&port->vio.timer, round_jiffies(jiffies + HZ));
        return;