| Message ID | 20200129181545.25302-1-dave@stgolabs.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | None | expand |
On Wed, Jan 29, 2020 at 10:15:45AM -0800, Davidlohr Bueso wrote: > We can avoid the unnecessary barrier on non LL/SC architectures, > such as x86. Instead, use the smp_mb__after_atomic() call. > > Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Reviewed-by: Johan Hovold <johan@kernel.org> > --- > drivers/usb/class/cdc-acm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c > index 62f4fb9b362f..0bc4b558f387 100644 > --- a/drivers/usb/class/cdc-acm.c > +++ b/drivers/usb/class/cdc-acm.c > @@ -842,7 +842,7 @@ static void acm_tty_unthrottle(struct tty_struct *tty) > clear_bit(ACM_THROTTLED, &acm->flags); > > /* Matches the smp_mb__after_atomic() in acm_read_bulk_callback(). */ > - smp_mb(); > + smp_mb__after_atomic(); > > acm_submit_read_urbs(acm, GFP_KERNEL); > } We have another barrier in USB serial which can also be relaxed this way. I'll post a patch shortly. Johan
ping? Can these please be picked up? On Wed, 29 Jan 2020, Davidlohr Bueso wrote: >We can avoid the unnecessary barrier on non LL/SC architectures, >such as x86. Instead, use the smp_mb__after_atomic() call. > >Signed-off-by: Davidlohr Bueso <dbueso@suse.de> >--- > drivers/usb/class/cdc-acm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > >diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c >index 62f4fb9b362f..0bc4b558f387 100644 >--- a/drivers/usb/class/cdc-acm.c >+++ b/drivers/usb/class/cdc-acm.c >@@ -842,7 +842,7 @@ static void acm_tty_unthrottle(struct tty_struct *tty) > clear_bit(ACM_THROTTLED, &acm->flags); > > /* Matches the smp_mb__after_atomic() in acm_read_bulk_callback(). */ >- smp_mb(); >+ smp_mb__after_atomic(); > > acm_submit_read_urbs(acm, GFP_KERNEL); > } >-- >2.16.4 >
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c index 62f4fb9b362f..0bc4b558f387 100644 --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -842,7 +842,7 @@ static void acm_tty_unthrottle(struct tty_struct *tty) clear_bit(ACM_THROTTLED, &acm->flags); /* Matches the smp_mb__after_atomic() in acm_read_bulk_callback(). */ - smp_mb(); + smp_mb__after_atomic(); acm_submit_read_urbs(acm, GFP_KERNEL); }
We can avoid the unnecessary barrier on non LL/SC architectures, such as x86. Instead, use the smp_mb__after_atomic() call. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> --- drivers/usb/class/cdc-acm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)